Evaluation of Small Form Factor Fiber Optic Interconnects for the NASA Electronics Parts and Packaging Program (NEPP)

NASA Technical Reports Server (NTRS)

Ott, Melanie; Thomes, W. Joe; Blair, Diana; Chuska, Rick; Switzer, Rob

2010-01-01

The Diamond AVIM optical fiber connector has been used for over a decade in flight environments. AVIM which stands for Aviation Intermediate Maintenance is always referenced as a fiber optic connector type from the DIN (Deutsches Institut fur Normung) family of optical fiber connectors. The newly available Mini AVIM and DMI (Definition Multimedia Interface) connectors also by Diamond provide similar features as the high performance AVIM with the added benefits of being small form factor for board mount and internal box use where long connectors and strain relief can not be accommodated. Transceiver, fiber laser technology and receiver optic technology based on small sized constraints will benefit the most by the reduction in connector form factor. It is for this reason that the Mini AVIM is being evaluated for multimode and single mode optical fiber use in both fiber based and cable based packaging configurations. In a fiber based termination, there are no cable materials to bond to the connector. The only bonding that is conducted is the mounting of the fiber with epoxy to the connector ferrules (which are called DMI ferrules). In a cable configuration, the compatibility of the connector subcomponents along with the upjacketing materials of the cable around the fiber needs to be considered carefully for termination fabrication. Cabled terminations will show greater insertion loss and high probability of failures during thermal cycling testing. This is due to the stressing of the combination of materials that each have different Coefficients of Thermal Expansion (CTE's) and that are bonded together to the connector subcomponents. As the materials flex during thermal excursions, forces are applied to the termination and can make the system fail if the grouping of materials (per their CTE's) are not compatible and this includes cable materials, epoxies, ferrule and connector body components. For this evaluation, multimode 100 micron core step index fiber was used for the fiber terminated condition, and single mode SMF-28 upjacketed with W.L. Gore Flexlite was used for the cabled configuration. For background purposes, a comparison is presented here for information purposes between the high performance AVIM connector features and the Mini AVIM small form factor connectors. Basic connector features are described here.

Single-Fiber Optical Link For Video And Control

NASA Technical Reports Server (NTRS)

Galloway, F. Houston

1993-01-01

Single optical fiber carries control signals to remote television cameras and video signals from cameras. Fiber replaces multiconductor copper cable, with consequent reduction in size. Repeaters not needed. System works with either multimode- or single-mode fiber types. Nonmetallic fiber provides immunity to electromagnetic interference at suboptical frequencies and much less vulnerable to electronic eavesdropping and lightning strikes. Multigigahertz bandwidth more than adequate for high-resolution television signals.

Apparatus for synthesis of a solar spectrum

DOEpatents

Sopori, Bhushan L.

1993-01-01

A xenon arc lamp and a tungsten filament lamp provide light beams that together contain all the wavelengths required to accurately simulate a solar spectrum. Suitable filter apparatus selectively direct visible and ultraviolet light from the xenon arc lamp into two legs of a trifurcated randomized fiber optic cable. Infrared light selectively filtered from the tungsten filament lamp is directed into the third leg of the fiber optic cable. The individual optic fibers from the three legs are brought together in a random fashion into a single output leg. The output beam emanating from the output leg of the trifurcated randomized fiber optic cable is extremely uniform and contains wavelengths from each of the individual filtered light beams. This uniform output beam passes through suitable collimation apparatus before striking the surface of the solar cell being tested. Adjustable aperture apparatus located between the lamps and the input legs of the trifurcated fiber optic cable can be selectively adjusted to limit the amount of light entering each leg, thereby providing a means of "fine tuning" or precisely adjusting the spectral content of the output beam. Finally, an adjustable aperture apparatus may also be placed in the output beam to adjust the intensity of the output beam without changing the spectral content and distribution of the output beam.

EGR distribution and fluctuation probe based on CO.sub.2 measurements

DOEpatents

Parks, II, James E; Partridge, Jr., William P; Yoo, Ji Hyung

2015-04-07

A diagnostic system having a single-port EGR probe and a method for using the same. The system includes a light source, an EGR probe, a detector and a processor. The light source may provide a combined light beam composed of light from a mid-infrared signal source and a mid-infrared reference source. The signal source may be centered at 4.2 .mu.m and the reference source may be centered at 3.8 .mu.m. The EGR probe may be a single-port probe with internal optics and a sampling chamber with two flow cells arranged along the light path in series. The optics may include a lens for focusing the light beam and a mirror for reflecting the light beam received from a pitch optical cable to a catch optical cable. The signal and reference sources are modulated at different frequencies, thereby allowing them to be separated and the signal normalized by the processor.

Radhard optical patchcords and packaging for satellites using liquid crystal polymers

NASA Astrophysics Data System (ADS)

O'Riorden, S.; Mahapatra, A.

2017-11-01

There are many advantages to employing fiber optics for high capacity satellite communication. However, optical cables can be susceptible to high radiation, temperature extremes and vacuum environment. Any hardware used in these systems must be rugged, durable and immune to the detrimental effects of the aforementioned conditions. Standard COTS optical fiber will darken when exposed to high levels of radiation limiting the effectiveness of the communications system. Of particular concern to satellites in GEO are energetic electrons, bursts of heavy particles due to solar storms which can cause total dose and single event effects (SEE). Conventional fiber optic cables have several issues performing in high radiation environments. Linden has patented and developed a novel cable using an extruded layer of Liquid Crystal Polymer (LCP) applied to commercially available fiber. Total dose effects are minimized by shielding with Liquid Crystal Polymer jacketing. It is a simple, inexpensive way to increase the radiation shielding and mechanical performance of cables in satellites while concomitantly providing hermeticity and thus increased fatigue factor for optical glass. • LCPs exposed to 5000 Mrad dose of gamma rays retain in excess of 90% of their mechanical properties. • LCPs exposed to 1 Mrad radiation dose with energetic protons retain almost 100% of their mechanical strength. Tensile modulus increases with exposure to the radiation. • Weight for weight the proton absorbing power of LCP is 25% better than that of aluminum. We will present experimental data on radhard optical patchcords.

New method for path-length equalization of long single-mode fibers for interferometry

NASA Astrophysics Data System (ADS)

Anderson, M.; Monnier, J. D.; Ozdowy, K.; Woillez, J.; Perrin, G.

2014-07-01

The ability to use single mode (SM) fibers for beam transport in optical interferometry offers practical advantages over conventional long vacuum pipes. One challenge facing fiber transport is maintaining constant differential path length in an environment where environmental thermal variations can lead to cm-level variations from day to night. We have fabricated three composite cables of length 470 m, each containing 4 copper wires and 3 SM fibers that operate at the astronomical H band (1500-1800 nm). Multiple fibers allow us to test performance of a circular core fiber (SMF28), a panda-style polarization-maintaining (PM) fiber, and a lastly a specialty dispersion-compensated PM fiber. We will present experimental results using precision electrical resistance measurements of the of a composite cable beam transport system. We find that the application of 1200 W over a 470 m cable causes the optical path difference in air to change by 75 mm (+/- 2 mm) and the resistance to change from 5.36 to 5.50Ω. Additionally, we show control of the dispersion of 470 m of fiber in a single polarization using white light interference fringes (λc=1575 nm, Δλ=75 nm) using our method.

High-stability 48-core bendable and movable optical cable for FAST telescope optical transmission system

NASA Astrophysics Data System (ADS)

Liu, Hongfei; Pan, Gaofeng; Lin, Zhong; Liu, Cheng; Zhu, Wenbai; Nan, Rendong; Li, Chunsheng; Gao, Guanjun; Luo, Wenyong; Jin, Chengjin; Song, Jinyou

2017-11-01

The construction of FAST telescope was completed in Guizhou province of China in September 2016, and a kind of novel high-stability 48-core bendable and movable optical cable was developed and applied in analog data optical transmission system of FAST. Novel structure and selective material of this optical cable ensure high stability of optical power in the process of cables round-trip motion when telescope is tracking a radio source. The 105 times bend and stretch accelerated experiment for this optical cable was implemented, and real-time optical and RF signal power fluctuation were measured. The physical structure of optical cables after 105 times round-trip motion is in good condition; the real-time optical power attenuation fluctuation is smaller than 0.044 dB; the real-time RF power fluctuation is smaller than 0.12 dB. The optical cable developed in this letter meets the requirement of FAST and has been applied in FAST telescope.

Optimization of Connector Position Offset for Bandwidth Enhancement of a Multimode Optical Fiber Link

NASA Technical Reports Server (NTRS)

Rawat, Banmali

2000-01-01

The multimode fiber bandwidth enhancement techniques to meet the Gigabit Ethernet standards for local area networks (LAN) of the Kennedy Space Center and other NASA centers have been discussed. Connector with lateral offset coupling between single mode launch fiber cable and the multimode fiber cable has been thoroughly investigated. An optimization of connector position offset for 8 km long optical fiber link at 1300 nm with 9 micrometer diameter single mode fiber (SMF) and 50 micrometer diameter multimode fiber (MMF) coupling has been obtained. The optimization is done in terms of bandwidth, eye-pattern, and bit pattern measurements. It is simpler, is a highly practical approach and is cheaper as no additional cost to manufacture the offset type of connectors is involved.

Technology Validation of Optical Fiber Cables for Space Flight Environments

NASA Technical Reports Server (NTRS)

Ott, Melanie N.; Friedberg, Patricia; Day, John H. (Technical Monitor)

2000-01-01

Periodically, commercially available (COTS) optical fiber cable assemblies are characterized for space flight usage under the NASA Electronic Parts and Packaging Program (NEPP). The purpose of this is to provide a family of optical fiber cable options to a variety of different harsh environments typical to space flight missions. The optical fiber cables under test are evaluated to bring out known failure mechanisms that are expected to occur during a typical mission. The tests used to characterize COTS cables include: (1) vacuum exposure, (2) thermal cycling, and (3) radiation exposure. Presented here are the results of the testing conducted at NASA Goddard Space Flight Center on COTS optical fiber cables over this past year. Several optical fiber cables were characterized for their thermal stability both during and after thermal cycling. The results show how much preconditioning is necessary for a variety of available cables to remain thermally stable in a space flight environment. Several optical fibers of dimensions 100/140/172 microns were characterized for their radiation effects at -125 C using the dose rate requirements of International Space Station. One optical fiber cable in particular was tested for outgassing to verify whether an acrylate coated fiber could be used in a space flight optical cable configuration.

Multiparameter fiber optic sensing system for monitoring enhanced geothermal systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Challener, William A

2014-12-04

The goal of this project was to design, fabricate and test an optical fiber cable which supports multiple sensing modalities for measurements in the harsh environment of enhanced geothermal systems. To accomplish this task, optical fiber was tested at both high temperatures and strains for mechanical integrity, and in the presence of hydrogen for resistance to darkening. Both single mode (SM) and multimode (MM) commercially available optical fiber were identified and selected for the cable based on the results of these tests. The cable was designed and fabricated using a tube-within-tube construction containing two MM fibers and one SM fiber,more » and without supporting gel that is not suitable for high temperature environments. Commercial fiber optic sensing instruments using Raman DTS (distributed temperature sensing), Brillouin DTSS (distributed temperature and strain sensing), and Raleigh COTDR (coherent optical time domain reflectometry) were selected for field testing. A microelectromechanical systems (MEMS) pressure sensor was designed, fabricated, packaged, and calibrated for high pressure measurements at high temperatures and spliced to the cable. A fiber Bragg grating (FBG) temperature sensor was also spliced to the cable. A geothermal well was selected and its temperature and pressure were logged. The cable was then deployed in the well in two separate field tests and measurements were made on these different sensing modalities. Raman DTS measurements were found to be accurate to ±5°C, even with some residual hydrogen darkening. Brillouin DTSS measurements were in good agreement with the Raman results. The Rayleigh COTDR instrument was able to detect some acoustic signatures, but was generally disappointing. The FBG sensor was used to determine the effects of hydrogen darkening, but drift over time made it unreliable as a temperature or pressure sensor. The MEMS sensor was found to be highly stable and accurate to better than its 0.1% calibration.« less

Fiber optic sensor system for detecting movement or position of a rotating wheel bearing

DOEpatents

Veeser, Lynn R.; Rodriguez, Patrick J.; Forman, Peter R.; Monahan, Russell E.; Adler, Jonathan M.

1997-01-01

An improved fiber optic sensor system and integrated sensor bearing assembly for detecting movement or position of a rotating wheel bearing having a multi-pole tone ring which produces an alternating magnetic field indicative of movement and position of the rotating member. A magneto-optical material, such as a bismuth garnet iron (B.I.G.) crystal, having discrete magnetic domains is positioned in the vicinity of the tone ring so that the domains align themselves to the magnetic field generated by the tone ring. A single fiber optic cable, preferably single mode fiber, carries light generated by a source of light to the B.I.G. crystal. The light passes through the B.I.G. crystal and is refracted at domain boundaries in the crystal. The intensity of the refracted light is indicative of the amount of alignment of the domains and therefore the strength of the magnetic field. The refracted light is carried by the fiber optic cable to an optic receiver where the intensity is measured and an electrical signal is generated and sent to a controller indicating the frequency of the changes in light intensity and therefore the rotational speed of the rotating wheel bearing.

Photonic-powered cable assembly

DOEpatents

Sanderson, Stephen N.; Appel, Titus James; Wrye, IV, Walter C.

2013-01-22

A photonic-cable assembly includes a power source cable connector ("PSCC") coupled to a power receive cable connector ("PRCC") via a fiber cable. The PSCC electrically connects to a first electronic device and houses a photonic power source and an optical data transmitter. The fiber cable includes an optical transmit data path coupled to the optical data transmitter, an optical power path coupled to the photonic power source, and an optical feedback path coupled to provide feedback control to the photonic power source. The PRCC electrically connects to a second electronic device and houses an optical data receiver coupled to the optical transmit data path, a feedback controller coupled to the optical feedback path to control the photonic power source, and a photonic power converter coupled to the optical power path to convert photonic energy received over the optical power path to electrical energy to power components of the PRCC.

Photonic-powered cable assembly

DOEpatents

Sanderson, Stephen N; Appel, Titus James; Wrye, IV, Walter C

2014-06-24

A photonic-cable assembly includes a power source cable connector ("PSCC") coupled to a power receive cable connector ("PRCC") via a fiber cable. The PSCC electrically connects to a first electronic device and houses a photonic power source and an optical data transmitter. The fiber cable includes an optical transmit data path coupled to the optical data transmitter, an optical power path coupled to the photonic power source, and an optical feedback path coupled to provide feedback control to the photonic power source. The PRCC electrically connects to a second electronic device and houses an optical data receiver coupled to the optical transmit data path, a feedback controller coupled to the optical feedback path to control the photonic power source, and a photonic power converter coupled to the optical power path to convert photonic energy received over the optical power path to electrical energy to power components of the PRCC.

Photonic Materials and Devices for RF (mmW) Sensing and Imaging

DTIC Science & Technology

2012-12-31

wave encoding thereby eliminating the need for bulky LO distribution cables. Also, optical processing techniques can be utilized to provide simple... optical powers, can be close to unity and low -noise photodetectors make the detection of exceedingly low power millimeter-waves practical. In... optically -filtering the modulated signal to pass only a single sideband and detecting the resultant optical signal with a low -noise photodetector we have

46 CFR 111.60-6 - Fiber optic cable.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Fiber optic cable. 111.60-6 Section 111.60-6 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-6 Fiber optic cable. Each fiber optic cable must— (a) Be...

46 CFR 111.60-6 - Fiber optic cable.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Fiber optic cable. 111.60-6 Section 111.60-6 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-6 Fiber optic cable. Each fiber optic cable must— (a) Be...

46 CFR 111.60-6 - Fiber optic cable.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Fiber optic cable. 111.60-6 Section 111.60-6 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-6 Fiber optic cable. Each fiber optic cable must— (a) Be...

46 CFR 111.60-6 - Fiber optic cable.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Fiber optic cable. 111.60-6 Section 111.60-6 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-6 Fiber optic cable. Each fiber optic cable must— (a) Be...

46 CFR 111.60-6 - Fiber optic cable.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Fiber optic cable. 111.60-6 Section 111.60-6 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-6 Fiber optic cable. Each fiber optic cable must— (a) Be...

Power inverter with optical isolation

DOEpatents

Duncan, Paul G.; Schroeder, John Alan

2005-12-06

An optically isolated power electronic power conversion circuit that includes an input electrical power source, a heat pipe, a power electronic switch or plurality of interconnected power electronic switches, a mechanism for connecting the switch to the input power source, a mechanism for connecting comprising an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or input bus bars, an optically isolated drive circuit connected to the switch, a heat sink assembly upon which the power electronic switch or switches is mounted, an output load, a mechanism for connecting the switch to the output load, the mechanism for connecting including an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or output bus bars, at least one a fiber optic temperature sensor mounted on the heat sink assembly, at least one fiber optic current sensor mounted on the load interconnection cable and/or output bus bar, at least one fiber optic voltage sensor mounted on the load interconnection cable and/or output bus bar, at least one fiber optic current sensor mounted on the input power interconnection cable and/or input bus bar, and at least one fiber optic voltage sensor mounted on the input power interconnection cable and/or input bus bar.

Distributed Fiber Optic Sensor for Early Detection of Rocky Slopes Movements

NASA Astrophysics Data System (ADS)

Minardo, Aldo; Picarelli, Luciano; Coscetta, Agnese; Zeni, Giovanni; Esposito, Giuseppe; Sacchi, Marco; Matano, Fabio; Caccavale, Mauro; Luigi, Zeni

2014-05-01

Distributed optical fiber sensors have in recent years gained considerable attention in structural and environmental monitoring due to specific advantages that, apart from the classical advantages common to all optical fiber sensors such as immunity to electromagnetic interferences, high sensitivity, small size and possibility to be embedded into the structures, multiplexing and remote interrogation capabilities [1], offer the unique feature of allowing the exploitation of a telecommunication grade optical fiber cable as the sensing element to measure deformation and temperature profiles over very long distances. In particular, distributed optical fiber sensors based on stimulated Brillouin scattering (SBS) through the so-called Brillouin Optical Time Domain Analysis (BOTDA), allow to measure strain and temperature profiles up to tens of kilometers with a strain accuracy of ±10µɛ and a temperature accuracy of ±1°C [2]. They have already been successfully employed in the monitoring of large civil and geotechnical structures such as bridges, tunnels, dams, pipelines allowing to identify and localize any kind of failures that can occur during their construction and operation [3,4]. In this paper we present the application of BOTDA to the monitoring of movements in a rocky slope, showing how the sensing optical fiber cable is able to detect the formation and follow the growth of fractures, and to identify their location along the slope, as well. The experimental results have been achieved on a test field located in the area of Naples (Italy), where a single mode optical fiber sensing cable has been deployed along a yellow tuffs slope, by spot gluing the cable with epoxy adhesive. In order to assess the validity of the proposed approach, a few existing cracks have been artificially enlarged and the magnitude and location of the induced strain peaks have been clearly identified by the sensing device. It should be emphasized that, due to the distributed nature of the sensor, no preliminary information about the possible displacement locations of rocks are required in advance. The sensing cable can be simply deployed in a zig-zag pattern path along the slope, for hundreds of meters, and the system will remotely detect and locate any displacements wherever they occur along the fiber cable path, so representing a powerful tool for early warning against possible rock slides. [1] J. M. López-Higuera, L. R. Cobo, A. Q. Incera, A. Cobo, " Fiber Optic Sensors in Structural Health Monitoring", Journal of Lightwave Technology, Vol. 29, pp.586-608, 2011. [2] A. Minardo, R. Bernini, L. Zeni, "Numerical analysis of single pulse and differential pulse-width pair BOTDA systems in the high spatial resolution regime", Optics Express, vol. 19, pp. 19233-19244, 2011. [3] A. Minardo, R. Bernini, L. Amato, L. Zeni, "Bridge monitoring using Brillouin fiber-optic sensors", IEEE Sensor Journal, Vol. 12 (1), pp. 145-150, 2012. [4] R. Bernini, A. Minardo, S. Ciaramella, V. Minutolo, L. Zeni, "Distributed strain measurement along a concrete beam via stimulated Brillouin scattering in optical fibers", International Journal of Geophysics, Vol. 2011, pp. 1-5, doi:10.1155/2011/710941, 2011.

Fiber optic cables for severe environment

NASA Astrophysics Data System (ADS)

Massarani, M. G.

1982-10-01

The most severe challenges to the fiber optic cable are related to nuclear weapons testing and other military applications. Nuclear experiments are conducted in deep underground holes. Cables connect the experimental device to recording stations positioned at a certain distance from ground zero. Attractive features provided by fiber optic cable technology include large cost advantages in cable purchase price, savings in handling cost due to the lighter weight, immunity to electromagnetic pulses (EMP), and the capability to transmit high data rates. Details of underground nuclear testing are discussed, taking into account the underground nuclear test environment, and questions of fiber optic cable design for the underground experiments. The use of fiber optics for the Ground Launched Cruise Missile Weapons System (GLCM) is also considered. Attention is given to the GLCM environment, and the proposed cable for GLCM application.

Comparison of Distributed Acoustic Sensing (DAS) from Fiber-Optic Cable to Three Component Geophones in an Underground Mine

NASA Astrophysics Data System (ADS)

Speece, M. A.; Nesladek, N. J.; Kammerer, C.; Maclaughlin, M.; Wang, H. F.; Lord, N. E.

2017-12-01

We conducted experiments in the Underground Education Mining Center on the Montana Tech campus, Butte, Montana, to make a direct comparison between Digital Acoustic Sensing (DAS) and three-component geophones in a mining setting. The sources used for this project where a vertical sledgehammer, oriented shear sledgehammer, and blasting caps set off in both unstemmed and stemmed drillholes. Three-component Geospace 20DM geophones were compared with three different types of fiber-optic cable: (1) Brugg strain, (2) Brugg temperature, and (3) Optical Cable Corporation strain. We attached geophones to the underground mine walls and on the ground surface above the mine. We attached fiber-optic cables to the mine walls and placed fiber-optic cable in boreholes drilled through an underground pillar. In addition, we placed fiber-optic cables in a shallow trench at the surface of the mine. We converted the DAS recordings from strain rate to strain prior to comparison with the geophone data. The setup of the DAS system for this project led to a previously unknown triggering problem that compromised the early samples of the DAS traces often including the first-break times on the DAS records. Geophones clearly recorded the explosives; however, the large amount of energy and its close distance from the fiber-optic cables seemed to compromise the entire fiber loop. The underground hammer sources produced a rough match between the DAS records and the geophone records. However, the sources on the surface of the mine, specifically the sources oriented inline with the fiber-optic cables, produced a close match between the fiber-optic traces and the geophone traces. All three types of fiber-optic cable that were in the mine produced similar results, and one type did not clearly outperform the others. Instead, the coupling of the cable to rock appears to be the most important factor determining DAS data quality. Moreover, we observed the importance of coupling in the boreholes, where fiber-optic cables that were pressed against the rock face with a spacer outperformed fiber-optic cables that were fully embedded within the grout filling the inside of the borehole.

On the mechanical coupling of a fiber optic cable used for distributed acoustic/vibration sensing applications—a theoretical consideration

NASA Astrophysics Data System (ADS)

Reinsch, Thomas; Thurley, Tom; Jousset, Philippe

2017-12-01

In recent years, fiber optic cables are increasingly used for the acquisition of dynamic strain changes for seismic surveys. When considering seismic amplitudes, one of the first questions arising is the mechanical coupling between optical fiber and the surrounding medium. Here we analyse the interaction of ground movement with a typical telecom-grade fiber optic cable from an existing telecommunication network deployed in a sand filled trench at the surface. Within the cable, the optical fiber is embedded in a gel-filled plastic tube. We apply Hooke’s law to calculate the stress needed to strain the optical fiber throughout the cable structure. In case the stress magnitude at the cable-sand interface as well as the gel-optical fiber interface is below the yield strength of the respective material, sand and gel, it can be regarded as an elastic medium. Hence, a multilayer radial symmetric model can be used to calculate the coupling of the optical fiber with the surrounding medium. We show that the transfer function has a -3 dB lower cut-off wavelength of about 22 m. The magnitude response of this telecom-grade fiber optic cable is therefore almost perfect at typical low frequency seismic waves. The approach presented here can be applied to various cable designs to estimate the strain transfer between ground movement and an optical fiber.

Fibre-optic distributed temperature sensing in combined sewer systems.

PubMed

Schilperoort, R P S; Clemens, F H L R

2009-01-01

This paper introduces the application of fibre-optic distributed temperature sensing (DTS) in combined sewer systems. The DTS-technique uses a fibre-optic cable that is inserted into a combined sewer system in combination with a laser instrument that performs measurements and logs the data. The DTS-technique allows monitoring in-sewer temperatures with dense spatial and temporal resolutions. The installation of a fibre-optic cable in a combined sewer system has proven feasible. The use of a single instrument in an easy accessible and safe location that can simultaneously monitor up to several hundreds of monitoring locations makes the DTS set-up easy in use and nearly free of maintenance. Temperature data from a one-week monitoring campaign in an 1,850 m combined sewer system shows the level of detail with which in-sewer processes that affect wastewater temperatures can be studied. Individual discharges from house-connections can be tracked in time and space. With a dedicated cable configuration the confluence of wastewater flows can be observed with a potential to derive the relative contributions of contributary flows to a total flow. Also, the inflow and in-sewer propagation of stormwater can be monitored.

A USB 2.0 computer interface for the UCO/Lick CCD cameras

NASA Astrophysics Data System (ADS)

Wei, Mingzhi; Stover, Richard J.

2004-09-01

The new UCO/Lick Observatory CCD camera uses a 200 MHz fiber optic cable to transmit image data and an RS232 serial line for low speed bidirectional command and control. Increasingly RS232 is a legacy interface supported on fewer computers. The fiber optic cable requires either a custom interface board that is plugged into the mainboard of the image acquisition computer to accept the fiber directly or an interface converter that translates the fiber data onto a widely used standard interface. We present here a simple USB 2.0 interface for the UCO/Lick camera. A single USB cable connects to the image acquisition computer and the camera's RS232 serial and fiber optic cables plug into the USB interface. Since most computers now support USB 2.0 the Lick interface makes it possible to use the camera on essentially any modern computer that has the supporting software. No hardware modifications or additions to the computer are needed. The necessary device driver software has been written for the Linux operating system which is now widely used at Lick Observatory. The complete data acquisition software for the Lick CCD camera is running on a variety of PC style computers as well as an HP laptop.

Walkaway-VSP survey using distributed optical fiber in China oilfield

NASA Astrophysics Data System (ADS)

Wu, Junjun; Yu, Gang; Zhang, Qinghong; Li, Yanpeng; Cai, Zhidong; Chen, Yuanzhong; Liu, Congwei; Zhao, Haiying; Li, Fei

2017-10-01

Distributed acoustic sensing (DAS) is a new type of replacement technology for geophysical geophone. DAS system is similar to high-density surface seismic geophone array. In the stage of acquisition, DAS can obtain the full well data with one shot. And it can provide enhanced vertical seismic profile (VSP) imaging and monitor fluids and pressures changes in the hydrocarbon production reservoir. Walkaway VSP data acquired over a former producing well in north eastern China provided a rich set of very high quality data. A standard VSP data pre-processing workflow was applied, followed by pre-stack Kirchhoff time migration. In the DAS pre-processing step we were faced with additional and special challenges: strong coherent noise due to cable slapping and ringing along the borehole casing. The single well DAS Walkaway VSP images provide a good result with higher vertical and lateral resolution than the surface seismic in the objective area. This paper reports on lessons learned in the handling of the wireline cable and subsequent special DAS data processing steps developed to remediate some of the practical wireline deployment issues. Optical wireline cable as a conveyance of fiber optic cables for VSP in vertical wells will open the use of the DAS system to much wider applications.

Fiber optical cable and connector system (FOCCoS) for PFS/ Subaru

NASA Astrophysics Data System (ADS)

de Oliveira, Antonio Cesar; de Oliveira, Lígia Souza; de Arruda, Marcio V.; Souza Marrara, Lucas; dos Santos, Leandro H.; Ferreira, Décio; dos Santos, Jesulino B.; Rosa, Josimar A.; Junior, Orlando V.; Pereira, Jeferson M.; Castilho, Bruno; Gneiding, Clemens; Junior, Laerte S.; de Oliveira, Claudia M.; Gunn, James; Ueda, Akitoshi; Takato, Naruhisa; Shimono, Atsushi; Sugai, Hajime; Karoji, Hiroshi; Kimura, Masahiko; Tamura, Naoyuki; Wang, Shiang-Yu; Murray, Graham; Le Mignant, David; Madec, Fabrice; Jaquet, Marc; Vives, Sebastien; Fisher, Charlie; Braun, David; Schwochert, Mark; Reiley, Daniel J.

2014-07-01

FOCCoS, "Fiber Optical Cable and Connector System" has the main function of capturing the direct light from the focal plane of Subaru Telescope using optical fibers, each one with a microlens in its tip, and conducting this light through a route containing connectors to a set of four spectrographs. The optical fiber cable is divided in 3 different segments called Cable A, Cable B and Cable C. Multi-fibers connectors assure precise connection among all optical fibers of the segments, providing flexibility for instrument changes. To assure strong and accurate connection, these sets are arranged inside two types of assemblies: the Tower Connector, for connection between Cable C and Cable B; and the Gang Connector, for connection between Cable B and Cable A. Throughput tests were made to evaluate the efficiency of the connections. A lifetime test connection is in progress. Cable C is installed inside the PFI, Prime Focus Instrument, where each fiber tip with a microlens is bonded to the end of the shaft of a 2-stage piezo-electric rotatory motor positioner; this assembly allows each fiber to be placed anywhere within its patrol region, which is 9.5mm diameter.. Each positioner uses a fiber arm to support the ferrule, the microlens, and the optical fiber. 2400 of these assemblies are arranged on a motor bench plate in a hexagonal-closed-packed disposition. All optical fibers from Cable C, protected by tubes, pass through the motors' bench plate, three modular plates and a strain relief box, terminating at the Tower Connector. Cable B is permanently installed at Subaru Telescope structure, as a link between Cable C and Cable A. This cable B starts at the Tower Connector device, placed on a lateral structure of the telescope, and terminates at the Gang Connector device. Cable B will be routed to minimize the compression, torsion and bending caused by the cable weight and telescope motion. In the spectrograph room, Cable A starts at the Gang Connector, crosses a distribution box and terminates in a slit device. Each slit device receives approximately 600 optical fibers, linearly arrayed in a curve for better orientation of the light to the spectrograph collimator mirror. Four sets of Gang Connectors, distribution boxes and Slit devices complete one Cable A. This paper will review the general design of the FOCCoS subsystem, methods used to manufacture the involved devices, and the needed tests results to evaluate the total efficiency of the set.

FOCCoS for Subaru PFS

NASA Astrophysics Data System (ADS)

Cesar de Oliveira, Antonio; Souza de Oliveira, Ligia; de Arruda, Marcio V.; Bispo dos Santos, Jesulino; Souza Marrara, Lucas; Bawden de Paula Macanhan, Vanessa; Batista de Carvalho Oliveira, João.; de Paiva Vilaça, Rodrigo; Dominici, Tania P.; Sodré, Laerte; Mendes de Oliveira, Claudia; Karoji, Hiroshi; Sugai, Hajime; Shimono, Atsushi; Tamura, Naoyuki; Takato, Naruhisa; Ueda, Akitoshi

2012-09-01

The Fiber Optical Cable and Connector System (FOCCoS), provides optical connection between 2400 positioners and a set of spectrographs by an optical fibers cable as part of Subaru PFS instrument. Each positioner retains one fiber entrance attached at a microlens, which is responsible for the F-ratio transformation into a larger one so that difficulties of spectrograph design are eased. The optical fibers cable will be segmented in 3 parts at long of the way, cable A, cable B and cable C, connected by a set of multi-fibers connectors. Cable B will be permanently attached at the Subaru telescope. The first set of multi-fibers connectors will connect the cable A to the cable C from the spectrograph system at the Nasmith platform. The cable A, is an extension of a pseudo-slit device obtained with the linear disposition of the extremities of the optical fibers and fixed by epoxy at a base of composite substrate. The second set of multi-fibers connectors will connect the other extremity of cable A to the cable B, which is part of the positioner's device structure. The optical fiber under study for this project is the Polymicro FBP120170190, which has shown very encouraging results. The kind of test involves FRD measurements caused by stress induced by rotation and twist of the fiber extremity, similar conditions to those produced by positioners of the PFS instrument. The multi-fibers connector under study is produced by USCONEC Company and may connect 32 optical fibers. The tests involve throughput of light and stability after many connections and disconnections. This paper will review the general design of the FOCCoS subsystem, methods used to fabricate the devices involved and the tests results necessary to evaluate the total efficiency of the set.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nekoogar, Faranak; Reynolds, Matthew; Lefton, Scott

A secure passive RFID tag system comprises at least one base station and at least one passive RFID tag. The tag includes a fiber optic cable with the cable ends sealed within the tag and the middle portion forming an external loop. The loop may be secured to at least portions of an object. The tag transmits and receives an optical signal through the fiber optic cable, and the cable is configured to be damaged or broken in response to removal or tampering attempts, wherein the optical signal is significantly altered if the cable is damaged or broken. The tagmore » transmits the optical signal in response to receiving a radio signal from the base station and compares the transmitted optical signal to the received optical signal. If the transmitted optical signal and the received optical signal are identical, the tag transmits an affirmative radio signal to the base station.« less

Fiber Optic Cable Assemblies for Space Flight 2: Thermal and Radiation Effects

NASA Technical Reports Server (NTRS)

Ott, Melanie N.

1998-01-01

Goddard Space Flight Center is conducting a search for space flight worthy fiber optic cable assemblies that will benefit all projects at all of the NASA centers. This paper is number two in a series of papers being issued as a result of this task to define and qualify space grade fiber optic cable assemblies. Though to qualify and use a fiber optic cable in space requires treatment of the cable assembly as a system, it is very important to understand the design and behavior of its parts. This paper addresses that need, providing information on cable components shrinkage testing and radiation testing results from recent experiments at Goddard Space Flight Center.

Cooperative Microsystems and Neural Interfaces

DTIC Science & Technology

2009-03-04

polyimide coil for wireless power/data transfer F. Solzbacher, University of Utah – K. Shenoy, Stanford • Demonstrated wireless operation of implanted...Approach: Collapse cable into a single biocompatible optical fiber. Challenge: develop and demonstrate low power multi-channel data acquisition chip

Laser Optics/Combustion Diagnostics.

DTIC Science & Technology

1986-07-01

of Blackbody at Various Temperatures (K). . . 153 21 Transmission Attenuation of Quartz Fiber ... ............ .. 155 22 Schematic Diagram of Receiver...transfer pro- time-multiplexed via different lengths of fiber -optic cable to gram (machine code) of the TN- 1710 controls the handshak- a single...linewidths depend upon temperature, pressure, and , composition of the medium as well as the J value of the line. Collisional effects, as demonstrated for

Small, Optically-Driven Power Source

NASA Technical Reports Server (NTRS)

Cockrum, Richard H.; Wang, Ke-Li J.

1988-01-01

Power transmitted along fiber-optic cables. Transmitted as infrared light along fiber-optic cable, converted to electricity to supply small electronic circuit. Power source and circuit remains electrically isolated from each other for safety or reduces electromagnetic interference. Array of diodes made by standard integrated-circuit techniques and packaged for mounting at end of fiber-optic cable.

Communications Via Undersea Cables: Present And Future

NASA Astrophysics Data System (ADS)

Paul, D. K.

1985-11-01

Advances in fiber optic technology in the past few years have firmly established the superiority of optical fiber to coaxial cables, particularly for large-capacity, long-haul transmission systems. Recently, several undersea fiber optic cable systems have been proposed by both common and noncommon carriers. This paper addresses the techno-economic implications of these applications, and includes a brief review of the current status of undersea cable technology and a projection of future demand and capabilities. The prospects for using high-speed, multifiber undersea cable systems for international communications, extension of these systems through fiber optic terrestrial distribution, and future developmental trends are critically assessed.

Integrated Structural and Cable Connector

NASA Technical Reports Server (NTRS)

Totah, R. S.

1982-01-01

Ball-and-socket coupling includes fiber-optic cable. Three steps couple two parts of fiber-optic cable: ball is inserted into socket; cone is released in, and cable moves toward plug. Sleeve is pulled to end of its travel and cable and plug are mated. Device is a quick-connect/disconnect coupling that has application in hazardous environments, such as space, undersea and nuclear installations.

System for effecting underwater coupling of optical fiber cables characterized by a novel lateral arm cable capture mechanism

NASA Astrophysics Data System (ADS)

Hillenbrand, Christopher F.

1995-03-01

A submarine trails one fiber optic cable and an undersea vehicle is controlled by this first cable. A missile/torpedo trails a second cable that is to be coupled to the first cable. The second cable has a segment suspended vertically underwater between a buoyant pod and a sea anchor type buoy. The undersea vehicle, or autonomous undersea vehicle, (AUV) hunts for the pod by conventional homing components, and cable capturing arms on the vehicle direct the cable's movement relative to the vehicle into a pod mating position that achieves optical coupling of the two cables. In one embodiment two arms are pivotably mounted to the vehicle's sides so one arm captures the suspended cable segment directing it into a slot so a male socket in the underside of the pod mates with a female socket in the slot. Another embodiment accomplishes the same result with a device in which the arms are formed as the off-shoots of a forked cable pickup device in the nose of the AUV.

Active optical cable for intrasatellite communications

NASA Astrophysics Data System (ADS)

Blasco, J.; Cano, D.; Navasquillo, O.; Esteban, M. A.

2017-11-01

DAS Photonics and Airbus Defence and Space (Spain) have been working for more than six years in the concept of an Active Optical Cable (AOC) for copper cable substitution. The main advantages that AOC offers are significant mass and size saving, better flexibility and routing of the cable and immunity to EMI.

Integrated Networks.

ERIC Educational Resources Information Center

Robinovitz, Stewart

1987-01-01

A strategy for integrated data and voice networks implemented at the University of Michigan is described. These networks often use multi-technologies, multi-vendors, and multi-transmission media that will be fused into a single integrated network. Transmission media include twisted-pair wire, coaxial cable, fiber optics, and microwave. (Author/MLW)

Characterization of the Twelve Channel 100/140 Micron Optical Fiber, Ribbon Cable and MTP Array Connector Assembly for Space Flight Environments

NASA Technical Reports Server (NTRS)

Ott, Melanie N.; Macmurphy, Shawn; Friedberg, Patricia; Day, John H. (Technical Monitor)

2002-01-01

Presented here is the second set of testing conducted by the Technology Validation Laboratory for Photonics at NASA Goddard Space Flight Center on the 12 optical fiber ribbon cable with MTP array connector for space flight environments. In the first set of testing the commercial 62.5/125 cable assembly was characterized using space flight parameters. The testing showed that the cable assembly would survive a typical space flight mission with the exception of a vacuum environment. Two enhancements were conducted to the existing technology to better suit the vacuum environment as well as the existing optoelectronics and increase the reliability of the assembly during vibration. The MTP assembly characterized here has a 100/140 optical commercial fiber and non outgassing connector and cable components. The characterization for this enhanced fiber optic cable assembly involved vibration, thermal and radiation testing. The data and results of this characterization study are presented which include optical in-situ testing.

Low temperature monitoring system for subsurface barriers

DOEpatents

Vinegar, Harold J [Bellaire, TX; McKinzie, II Billy John [Houston, TX

2009-08-18

A system for monitoring temperature of a subsurface low temperature zone is described. The system includes a plurality of freeze wells configured to form the low temperature zone, one or more lasers, and a fiber optic cable coupled to at least one laser. A portion of the fiber optic cable is positioned in at least one freeze well. At least one laser is configured to transmit light pulses into a first end of the fiber optic cable. An analyzer is coupled to the fiber optic cable. The analyzer is configured to receive return signals from the light pulses.

Manufacturing Methods and Technology Program for Ruggedized Tactical Fiber Optic Cable.

DTIC Science & Technology

1979-10-26

cores manufactured on this unit since the improvements were incorporated. An automatic diameter control unit with a laser micrometer sensor has been...fiber optic sensor systems for the TACA-MO aircraft and power encoding, an 18-port single fiber data bus for the Autonetics information transfer...echnica del Estado, Santiago, Chile in 1958. He received a degree in Industrial Chemical Engineering from Escuela de Ingenieros Industriales , Santiago

Qualification of Fiber Optic Cables for Martian Extreme Temperature Environments

NASA Technical Reports Server (NTRS)

Ramesham, Rajeshuni; Lindensmith, Christian A.; Roberts, William T.; Rainen, Richard A.

2011-01-01

Means have been developed for enabling fiber optic cables of the Laser Induced Breakdown Spectrometer instrument to survive ground operations plus the nominal 670 Martian conditions that include Martian summer and winter seasons. The purpose of this development was to validate the use of the rover external fiber optic cabling of ChemCam for space applications under the extreme thermal environments to be encountered during the Mars Science Laboratory (MSL) mission. Flight-representative fiber optic cables were subjected to extreme temperature thermal cycling of the same diurnal depth (or delta T) as expected in flight, but for three times the expected number of in-flight thermal cycles. The survivability of fiber optic cables was tested for 600 cumulative thermal cycles from -130 to +15 C to cover the winter season, and another 1,410 cumulative cycles from -105 to +40 C to cover the summer season. This test satisfies the required 3 times the design margin that is a total of 2,010 thermal cycles (670 x 3). This development test included functional optical transmission tests during the course of the test. Transmission of the fiber optic cables was performed prior to and after 1,288 thermal cycles and 2,010 thermal cycles. No significant changes in transmission were observed on either of the two representative fiber cables subject through the 3X MSL mission life that is 2,010 thermal cycles.

Multi-fibers connectors systems for FOCCoS-PFS-Subaru

NASA Astrophysics Data System (ADS)

de Oliveira, Antonio Cesar; de Oliveira, Ligia Souza; Souza Marrara, Lucas; dos Santos, Leandro Henrique; Vital de Arruda, Marcio; dos Santos, Jesulino Bispo; Ferreira, Décio; Rosa, Josimar Aparecido; de Paiva Vilaça, Rodrigo; Sodré, Laerte; de Oliveira, Claudia Mendes; Gunn, James E.

2014-07-01

The Fiber Optical Cable and Connector System (FOCCoS), provides optical connection between 2400 positioners and a set of spectrographs through optical fibers cables as part of PFS instrument for Subaru telescope. The optical fiber cable will be segmented in 3 parts along the route, cable A, cable B and cable C, connected by a set of multi-fiber connectors. The company USCONEC produces the multi-fiber connector under study. The USCONEC 32F model can connect 32 optical fibers in a 4 x 8 matrix arrangement. The ferrules are made of a durable composite, Polyphenylene Sulfide (PPS) based thermoplastic. The connections are held in place by a push-on/pull-off latch, and the connector can also be distinguished by a pair of metal guide pins that protrude from the front of the connector. Two fibers per connector will be used for monitoring the connection procedure. It was found to be easy to polish and it is small enough to be mounted in groups. Highly multiplexed instruments like PFS require a fiber connector system that can deliver excellent optical performance and reliability. PFS requires two different types of structures to organize the connectors. The Tower Connector system, with 80 multi-fiber connectors, will be a group of connectors for connecting cable B (Telescope Structure) with cable C (Positioners Plate). The Gang Connector system is a group of 8 gang connectors, each one with 12 multi-fibers connectors, for connecting cable B (Telescope Structure) with cable A (Spectrograph). The bench tests with these connector systems and the chosen fibers should measure the throughput of light and the stability after many connections and disconnections. In this paper we describe tests and procedures to evaluate the throughput and FRD increment. The lifetime of the ferrules is also in evaluation.

A novel method for surface defect inspection of optic cable with short-wave infrared illuminance

NASA Astrophysics Data System (ADS)

Chen, Xiaohong; Liu, Ning; You, Bo; Xiao, Bin

2016-07-01

Intelligent on-line detection of cable quality is a crucial issue in optic cable factory, and defects on the surface of optic cable can dramatically depress cable grade. Manual inspection in optic cable quality cannot catch up with the development of optic cable industry due to its low detection efficiency and huge human cost. Therefore, real-time is highly demanded by industry in order to replace the subjective and repetitive process of manual inspection. For this reason, automatic cable defect inspection has been a trend. In this paper, a novel method for surface defect inspection of optic cable with short-wave infrared illuminance is presented. The special condition of short-wave infrared cannot only provide illumination compensation for the weak illumination environment, but also can avoid the problem of exposure when using visible light illuminance, which affects the accuracy of inspection algorithm. A series of image processing algorithms are set up to analyze cable image for the verification of real-time and veracity of the detection method. Unlike some existing detection algorithms which concentrate on the characteristics of defects with an active search way, the proposed method removes the non-defective areas of the image passively at the same time of image processing, which reduces a large amount of computation. OTSU algorithm is used to convert the gray image to the binary image. Furthermore, a threshold window is designed to eliminate the fake defects, and the threshold represents the considered minimum size of defects ε . Besides, a new regional suppression method is proposed to deal with the edge burrs of the cable, which shows the superior performance compared with that of Open-Close operation of mathematical morphological in the boundary processing. Experimental results of 10,000 samples show that the rates of miss detection and false detection are 2.35% and 0.78% respectively when ε equals to 0.5 mm, and the average processing period of one frame image is 2.39 ms. All the improvements have been verified in the paper to show the ability of our inspection method for optic cable.

System for effecting underwater coupling of optical fiber cables characterized by a novel V-probe cable capture mechanism

NASA Astrophysics Data System (ADS)

Hillenbrand, Christopher F.; Barron, Thomas D.; Nugent, David M.

1995-03-01

A submarine trails one fiber optic cable and an undersea vehicle is controlled by this first cable. A missile/torpedo trails a second cable that is to be coupled to the first cable. The second cable has a segment suspended vertically underwater between a buoyant pod and a sea anchor type buoy. The undersea vehicle, or Autonomous Undersea Vehicle, (AUV) hunts for the pod by conventional homing means. A forked cable pickup device in the nose of the AUV captures the suspended cable segment directing it into a slot so a male socket in the underside of the pod mates with a female socket in the slot.

Study on the mechanical analysis and the testing technology of the optical fiber cables released from the bobbin

NASA Astrophysics Data System (ADS)

Wang, Rong; Li, Zhen-hua; Bian, Bao-min; Liu, Cheng-lin; Ji, Yun-jing

2014-12-01

Accurate measurements of forces applied to the optical cable reels with high spinning speeds, will render information on the breakdown of optical fibers, and thus improve the odds of success and un-winding efficiency. In this paper we analyze and deduce the cable wire stress at high pay-off speeds. A high-sensitive opti-mechanical testing sensory device is designed to measure both the axial tension of the cables and the radial pressure of the cable reels at varying stress points simultaneously. The time resolution of this new device is less than 0.015ms, the response time is up to 15μs, and its sensitivity is about 500pc/N, which satisfies the mechanical testing requirements at high spinning speeds. In addition, the spinning speed of 260m/s led to the break-down of the optical fibers, and the spinning speed of 250m/s tested finally led to a deceleration near the end of the broken fibers. It is obvious that this kit can meet the requirement to obtain the periodic signals of the varying forces for each layer and each turn of optical fiber cables. Moreover, we found that the pay-off fiber cable is safe with the unwinding speed of 250m/s and the break-down of optical cables happens during the deceleration process. However, it is under the unwinding speed of 260m/s that pay-off fiber cables broke during the experiment. The abnormal breakdown signals are captured at these unwinding speeds, respectively.

Thermal injury secondary to laparoscopic fiber-optic cables.

PubMed

Hindle, A Katharine; Brody, Fred; Hopkins, Vernon; Rosales, Greg; Gonzalez, Florencia; Schwartz, Arnold

2009-08-01

Laparoscopy requires a reliable light source to provide adequate visualization. However, thermal energy is produced as a by-product from the optical cable. This study attempts to quantify the degree of possible thermal damage secondary to the fiber-optic light source. Using a digital thermometer, temperature measurements were recorded at the tip of optical cables from five different light sources (Karl Storz, Inc., Tuttlingen, Germany). Temperature measurements were recorded with new and old bulbs. The tip of the cable was applied to surgical drapes and the time to charring was recorded. Subsequently, the tip of the optical cable was applied to a porcine model and tissue samples were obtained after varying amounts of time (5, 15, 30, 60, and 90 s). Sections of the damaged tissue were prepared for microscopic evaluation. Parameters for thermal injury included extent of epidermal, dermal, and subcutaneous fat damage and necrosis. The lateral extent and depth of injury were measured. The maximum temperature at the tip of the optical cable varied between 119.5 degrees C and 268.6 degrees C. When surgical drapes were exposed to the tip of the light source, the time to char was 3-6 s. The degree and volume of injury increased with longer exposure times, and significant injury was recorded with the optical cable 3 mm from the skin. This study demonstrates that the temperature at the tip of the optical light cord can induce extensive damage. The by-product of light, heat, can produce immediate superficial tissue necrosis that can extend into the subcutaneous fat even when the optical tip is not in direct contact with the skin. In addition, our study shows the variation in temperature that exists between light sources and bulb status. Overall, surgeons must realize and respect the potential complications associated with optical technology.

Optics vs copper: from the perspective of "Thunderbolt" interconnect technology

NASA Astrophysics Data System (ADS)

Cheng, Hengju; Krause, Christine; Ko, Jamyuen; Gao, Miaobin; Liu, Guobin; Wu, Huichin; Qi, Mike; Lam, Chun-Chit

2013-02-01

Interconnect technology has been progressed at a very fast pace for the past decade. The signaling rates have steadily increased from 100:Mb/s to 25Gb/s. In every generation of interconnect technology evolution, optics always seems to take over at first, however, at the end, the cost advantage of copper wins over. Because of this, optical interconnects are limited to longer distance links where the attenuation in copper cable is too large for the integrated circuits to compensate. Optical interconnect has long been viewed as the premier solution in compared with copper interconnect. With the release of Thunderbolt technology, we are entering a new era in consumer electronics that runs at 10Gb/s line rate (20Gb/s throughput per connector interface). Thunderbolt interconnect technology includes both active copper cables and active optical cables as the transmission media which have very different physical characteristics. In order for optics to succeed in consumer electronics, several technology hurdles need to be cleared. For example, the optical cable needs to handle the consumer abuses such as pinch and bend. Also, the optical engine used in the active optical cable needs to be physically very small so that we don't change the looks and feels of the cable/connector. Most importantly, the cost of optics needs to come down significantly to effectively compete with the copper solution. Two interconnect technologies are compared and discussed on the relative cost, power consumption, form factor, density, and future scalability.

Fiber-optic security monitoring sensor

NASA Astrophysics Data System (ADS)

Englund, Marja; Ipatti, Ari; Karioja, Pentti

1997-09-01

In security monitoring, fiber-optic sensors are advantageous because strong and rugged optical fibers are thin, light, flexible and immune to electromagnetic interference. Optical fibers packaged into cables, such as, building and underground cables, can be used to detect even slightest disturbances, movements, vibrations, pressure changes and impacts along their entire length. When running an optical cable around a structure, and when using speckle pattern recognition technique for alarm monitoring, the distributed monitoring of the structure is possible. The sensing cable can be strung along fences, buried underground, embedded into concrete, mounted on walls, floors and ceilings, or wrapped around the specific components. In this paper, a fiber-optic security monitoring sensor based on speckle pattern monitoring is described. The description of the measuring method and the results of the experimental fiber installations are given. The applicability of embedded and surface mounted fibers to monitor the pressure and impact induced vibrations of fences and concrete structures as well as the loosening of critical parts in a power plant machinery were demonstrated in field and laboratory conditions. The experiences related to the applications and optical cable types are also discussed.

Fiber optic security monitoring sensor

NASA Astrophysics Data System (ADS)

Englund, Marja; Ipatti, Ari; Karioja, Pentti

1997-09-01

In security monitoring, fiber-optic sensors are advantageous because strong and rugged optical fibers are thin, light, flexible and immune to electromagnetic interference. Optical fibers packaged into cables, such as, building and underground cables, can be used to detect even slightest disturbances, movements, vibrations, pressure changes and impacts along their entire length. When running an optical cable around a structure, and when using speckle pattern recognition technique for alarm monitoring, the distributed monitoring of the structure is possible. The sensing cable can be strung along fences, buried underground, embedded into concrete, mounted on walls, floors and ceilings, or wrapped around the specific components. In this paper, a fiber-optic security monitoring sensor based on speckle pattern monitoring is described. The description of the measuring method and the results of the experimental fiber installations are given. The applicability of embedded and surface mounted fibers to monitor the pressure and impact induced vibrations of fences and concrete structures as well as the loosening of critical parts in a power plant machinery were demonstrated in field and laboratory conditions. The experiences related to the applications and optical cable types are also discussed.

Lightning vulnerability of fiber-optic cables.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinez, Leonard E.; Caldwell, Michele

2008-06-01

One reason to use optical fibers to transmit data is for isolation from unintended electrical energy. Using fiber optics in an application where the fiber cable/system penetrates the aperture of a grounded enclosure serves two purposes: first, it allows for control signals to be transmitted where they are required, and second, the insulating properties of the fiber system help to electrically isolate the fiber terminations on the inside of the grounded enclosure. A fundamental question is whether fiber optic cables can allow electrical energy to pass through a grounded enclosure, with a lightning strike representing an extreme but very importantmore » case. A DC test bed capable of producing voltages up to 200 kV was used to characterize electrical properties of a variety of fiber optic cable samples. Leakage current in the samples were measured with a micro-Ammeter. In addition to the leakage current measurements, samples were also tested to DC voltage breakdown. After the fiber optic cables samples were tested with DC methods, they were tested under representative lightning conditions at the Sandia Lightning Simulator (SLS). Simulated lightning currents of 30 kA and 200 kA were selected for this test series. This paper documents measurement methods and test results for DC high voltage and simulated lightning tests performed at the Sandia Lightning Simulator on fiber optic cables. The tests performed at the SLS evaluated whether electrical energy can be conducted inside or along the surface of a fiber optic cable into a grounded enclosure under representative lightning conditions.« less

Applications Of Measurement Techniques To Develop Small-Diameter, Undersea Fiber Optic Cables

NASA Astrophysics Data System (ADS)

Kamikawa, Neil T.; Nakagawa, Arthur T.

1984-12-01

Attenuation, strain, and optical time domain reflectometer (OTDR) measurement techniques were applied successfully in the development of a minimum-diameter, electro-optic sea floor cable. Temperature and pressure models for excess attenuation in polymer coated, graded-index fibers were investigated analytically and experimentally using these techniques in the laboratory. The results were used to select a suitable fiber for the cable. Measurements also were performed on these cables during predeployment and sea-trial testing to verify laboratory results. Application of the measurement techniques and results are summarized in this paper.

Effect of Solar Radiation on Fiber Optic Cables Used in Distributed Temperature Sensing (DTS) Applications

NASA Astrophysics Data System (ADS)

Neilson, B. T.; Hatch, C. E.; Bingham, Q. G.; Tyler, S. W.

2008-12-01

In recent years, distributed temperature sensing (DTS) has enjoyed steady increases in the number and diversity of applications. Because fiber optic cables used for DTS are typically sheathed in dark materials resistant to UV deterioration, the question arises of how shortwave solar radiation penetrating a water column influences the accuracy of absolute DTS-derived temperatures. Initial calculations of these affects considered: shortwave radiation as a function of time of day, water depth, and water clarity; fiber optic cable dimensions; and fluid velocity. These indicate that for clear waterbodies with low velocities and shallow depths, some heating on the cable is likely during peak daily solar radiation. Given higher water velocities, substantial increases in turbidity, and/or deeper water, there should be negligible solar heating on the cable. To confirm these calculations, a field study was conducted to test the effects of solar radiation by installing two types of fiber optic cable at multiple, uniform depths in a trapezoidal canal with constant flow determined by a controlled release from Porcupine Dam near Paradise, Utah. Cables were installed in water depths from 0.05 to 0.79 m in locations of faster (center of canal) and slower (sidewall) water velocities. Thermister strings were installed at the same depths, but shielded from solar radiation and designed to record absolute water temperatures. Calculations predict that at peak solar radiation, in combination with shallow depths and slow velocities, typical fiber-optic cable is likely to experience heating greater than the ambient water column. In this study, DTS data show differences of 0.1-0.2°C in temperatures as seen by cables separated vertically by 0.31 m on the sidewall and center of the channel. Corresponding thermister data showed smaller vertical differences (~0.03-0.1°C) suggesting thermal stratification was also present in the canal. However, the magnitude of the DTS differences could not be fully explained by stratification alone. Additional information from cables installed in a shallow, near-zero velocity pool showed significantly higher temperature differences with cable depth when compared to the cable in the higher-velocity canal flows. This indicates a higher potential for heating of fiber-optic cable in stagnant, shallow waters. With sufficient water velocities and depths, the effect of shortwave solar radiation on DTS measurement accuracy via heating of the fiber- optic cable is negligible. Particular care in experimental design is recommended in shallow or low-velocity systems, including consideration of solar radiation, and independent quantification of (or calibration for) absolute temperatures.

47 CFR 32.2422 - Underground cable.

Code of Federal Regulations, 2013 CFR

2013-10-01

... cable. This subsidiary record category shall include the original cost of optical fiber cable and other..., Buried Cable. (d) The cost of cables leading from the main distributing frame or equivalent to central...

47 CFR 32.2422 - Underground cable.

Code of Federal Regulations, 2010 CFR

2010-10-01

... cable. This subsidiary record category shall include the original cost of optical fiber cable and other..., Buried Cable. (d) The cost of cables leading from the main distributing frame or equivalent to central...

47 CFR 32.2422 - Underground cable.

Code of Federal Regulations, 2014 CFR

2014-10-01

... cable. This subsidiary record category shall include the original cost of optical fiber cable and other..., Buried Cable. (d) The cost of cables leading from the main distributing frame or equivalent to central...

47 CFR 32.2422 - Underground cable.

Code of Federal Regulations, 2011 CFR

2011-10-01

... cable. This subsidiary record category shall include the original cost of optical fiber cable and other..., Buried Cable. (d) The cost of cables leading from the main distributing frame or equivalent to central...

47 CFR 32.2422 - Underground cable.

Code of Federal Regulations, 2012 CFR

2012-10-01

... cable. This subsidiary record category shall include the original cost of optical fiber cable and other..., Buried Cable. (d) The cost of cables leading from the main distributing frame or equivalent to central...

Miniature and Molecularly Specific Optical Screening Technologies for Breast Cancer

DTIC Science & Technology

2008-10-01

commercially available dual-channel transimpedance amplifier circuit boards (Boston Electronics, TWAMP). Preliminary results with the imaging probe...connected to a current amplifier via a coaxial cable for diffuse reflectance measurements. This new probe is named P4-3 and schematics of the system and...probe. With the single pixel device a single-channel current amplifier (Terahertz Technologies, PDA-750) could easily read and collect the photocurrent

Modeling of a 10-km optical link exploiting power-over-fiber for cabled submarine observatories

NASA Astrophysics Data System (ADS)

Dimitriadou, Evangelia; Ghisa, Laura; Quintard, Véronique; Guégan, Mikael; Pérennou, André

2017-11-01

The modeling of the simultaneous propagation of high-power and bidirectional data along the same 10-km-long single-mode fiber is discussed. The intense signal carries the energy needed to supply an instrument in the context of cabled submarine observatories. The considered mathematical description takes into account the fiber's nonlinear behavior in terms of Raman and Brillouin scattering to describe spectral propagation in the static regime. By testing our model against measurements, its validity is evaluated. Preliminary results are promising and reveal the path to follow for its improvement.

Fiber optic submarine cables cuts cost modeling and cable protection aspects

NASA Astrophysics Data System (ADS)

Al-Lawati, Ali

2015-03-01

This work presents a model to calculate costs associated with submarine fiber optic cable cuts. It accounts for both fixed and variable factors determining cost of fixing cables and restoring data transmission. It considers duration of a cut, capacity of fibers, number of fiber pairs and expected number of cuts during cable life time. Moreover, it provides templates for initial feasibility assessments by comparing cut costs to cost of different cable protection schemes. It offers a needed tool to assist in guiding decision makers in selecting type of cable, length and depth of cable burial in terms of increase in initial investment due to adapting such protection methods, and compare it to cost of cuts repair and alternative restoration paths for data.

Synopsis of fiber optics in harsh environments

NASA Astrophysics Data System (ADS)

Pirich, Ronald

2014-09-01

Fiber optic technology is making significant advances for use in a number of harsh environments, such as air and space platforms. Many of these applications involve integration into systems which make extensive use of optical fiber for high bandwidth signal transmission. The large signal transmission bandwidth of optical fiber has a large and positive impact on the overall performance and weight of the cable harness. There are many benefits of fiber optic systems for air and space harsh environment applications, including minimal electromagnetic interference and environmental effects, lightweight and smaller diameter cables, greater bandwidth, integrated prognostics and diagnostics and the ability to be easily upgraded. To qualify and use a fiber optic cable in space and air harsh environments requires treatment of the cable assembly as a system and understanding the design and behavior of its parts. Many parameters affect an optical fiber's ability to withstand a harsh temperature and radiation environment. The space radiation environment is dependent on orbital altitude, inclination and time, contains energetic magnetically-trapped electrons in the outer Van Allen radiation belt, trapped protons in the inner belt and solar event protons and ions. Both transient and permanent temperature and radiation have an attenuation effect on the performance of the cable fiber. This paper presents an overview of defining fiber optic system and component performance by identifying operating and storage environmental requirements, using appropriate standards to be used in fiber optic cable assembly manufacturing and integration, developing inspection methods and fixtures compliant with the selected standards and developing a fiber optic product process that assures compliance with each design requirement.

Twelve Channel Optical Fiber Connector Assembly: From Commercial Off the Shelf to Space Flight Use

NASA Technical Reports Server (NTRS)

Ott, Melaine N.

1998-01-01

The commercial off the shelf (COTS) twelve channel optical fiber MTP array connector and ribbon cable assembly is being validated for space flight use and the results of this study to date are presented here. The interconnection system implemented for the Parallel Fiber Optic Data Bus (PFODB) physical layer will include a 100/140 micron diameter optical fiber in the cable configuration among other enhancements. As part of this investigation, the COTS 62.5/125 microns optical fiber cable assembly has been characterized for space environment performance as a baseline for improving the performance of the 100/140 micron diameter ribbon cable for the Parallel FODB application. Presented here are the testing and results of random vibration and thermal environmental characterization of this commercial off the shelf (COTS) MTP twelve channel ribbon cable assembly. This paper is the first in a series of papers which will characterize and document the performance of Parallel FODB's physical layer from COTS to space flight worthy.

A 4-channel coil array interconnection by analog direct modulation optical link for 1.5-T MRI.

PubMed

Yuan, Jing; Wei, Juan; Shen, Gary X

2008-10-01

Optical glass fiber shows great advantages over coaxial cables in terms of electromagnetic interference, thus, it should be considered a potential alternative for magnetic resonance imaging (MRI) receive coil interconnection, especially for a large number coil array at high field. In this paper, we propose a 4-channel analog direct modulation optical link for a 1.5-T MRI coil array interconnection. First, a general direct modulated optical link is compared to an external modulated optical link. And then the link performances of the proposed direct modulated optical link, including power gain, frequency response, and dynamic range, are analyzed and measured. Phantom and in vivo head images obtained using this optical link are demonstrated for comparison with those obtained by cable connections. The signal-to-noise (SNR) analysis shows that the optical link achieves 6%-8% SNR a improvement over coaxial cables by elimination of electrical interference between cables during MR signal transmission.

Microinterferometer transducer

DOEpatents

Corey, III, Harry S.

1979-01-01

An air-bearing microinterferometer transducer is provided for increased accuracy, range and linearity over conventional displacement transducers. A microinterferometer system is housed within a small compartment of an air-bearing displacement transducer housing. A movable cube corner reflector of the interferometer is mounted to move with the displacement gauging probe of the transducer. The probe is disposed for axial displacement by means of an air-bearing. Light from a single frequency laser is directed into an interferometer system within the transducer housing by means of a self-focusing fiber optic cable to maintain light coherency. Separate fringe patterns are monitored by a pair of fiber optic cables which transmit the patterns to a detecting system. The detecting system includes a bidirectional counter which counts the light pattern fringes according to the direction of movement of the probe during a displacement gauging operation.

Thermal coefficient of delay for various coaxial and fiber-optic cables

NASA Technical Reports Server (NTRS)

Lutes, G. F.; Diener, W.

1989-01-01

Data are presented on the thermal coefficient of delay for various coaxial and fiber optic cables, as measured by the Frequency and Timing Systems Engineering Group and the Time and Frequency Systems Research Group. The measured pressure coefficient of delay is also given for the air-dielectric coaxial cables. A description of the measurement method and a description of each of the cables and its use at JPL and in the DSN are included. An improvement in frequency and phase stability by a factor of ten is possible with the use of fiber optics.

Reliability in fiber optic cable harness manufacturing

NASA Astrophysics Data System (ADS)

McCoy, Bruce M.

Key aspects of manufacturing cable harnesses for aircraft and spacecraft that incorporate optical fiber/cables along with traditional wiring are discussed. Issues regarding feasibility of automation of assembly processes, manual assembly, testing, installation, quality assurance, reliability and maintainability are addressed. Training procedures, formal training programs, and their results are reviewed.

Wide-area-distributed storage system for a multimedia database

NASA Astrophysics Data System (ADS)

Ueno, Masahiro; Kinoshita, Shigechika; Kuriki, Makato; Murata, Setsuko; Iwatsu, Shigetaro

1998-12-01

We have developed a wide-area-distribution storage system for multimedia databases, which minimizes the possibility of simultaneous failure of multiple disks in the event of a major disaster. It features a RAID system, whose member disks are spatially distributed over a wide area. Each node has a device, which includes the controller of the RAID and the controller of the member disks controlled by other nodes. The devices in the node are connected to a computer, using fiber optic cables and communicate using fiber-channel technology. Any computer at a node can utilize multiple devices connected by optical fibers as a single 'virtual disk.' The advantage of this system structure is that devices and fiber optic cables are shared by the computers. In this report, we first described our proposed system, and a prototype was used for testing. We then discussed its performance; i.e., how to read and write throughputs are affected by data-access delay, the RAID level, and queuing.

Fiber optic controls for aircraft engines - Issues and implications

NASA Technical Reports Server (NTRS)

Dasgupta, Samhita; Poppel, Gary L.; Anderson, William P.

1991-01-01

Some of the issues involved with the application of fiber-optic controls for aircraft engines in the harsh operating environment are addressed, with emphasis on fiber-optic temperature, pressure, position, and speed sensors. Criteria are established to evaluate the optical modulation technique, the sensor/control unit interconnection, and the electrooptic architecture. Single mode and polarization dependent sensor types, sensors which depend on the reflection and/or transmission of light through the engine environment, and intensity-based analog sensors are eliminated as a possible candidate for engine implementation. Fiber-optic harnesses tested for their optical integrity, temperature stability, and mechanical strength, exhibit a capacity to meet mechanical strength requirements and still gain a significant reduction in cable weight.

15 CFR 2301.2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... primary television or radio broadcast station, including, but not limited to, coaxial cable, optical fiber..., optical fiber communications equipment, and other means of transmitting, emitting, storing, and receiving..., and coaxial or fiber optic cable. Noncommercial educational broadcast station or public broadcast...

15 CFR 2301.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... primary television or radio broadcast station, including, but not limited to, coaxial cable, optical fiber..., optical fiber communications equipment, and other means of transmitting, emitting, storing, and receiving..., and coaxial or fiber optic cable. Noncommercial educational broadcast station or public broadcast...

15 CFR 2301.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... primary television or radio broadcast station, including, but not limited to, coaxial cable, optical fiber..., optical fiber communications equipment, and other means of transmitting, emitting, storing, and receiving..., and coaxial or fiber optic cable. Noncommercial educational broadcast station or public broadcast...

47 CFR 32.2426 - Intrabuilding network cable.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) Nonmetallic cable. This subsidiary record category shall include the original cost of optical fiber cable and... between buildings on one customer's same premises. Intrabuilding network cables are used to distribute...

47 CFR 32.2426 - Intrabuilding network cable.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) Nonmetallic cable. This subsidiary record category shall include the original cost of optical fiber cable and... between buildings on one customer's same premises. Intrabuilding network cables are used to distribute...

47 CFR 32.2426 - Intrabuilding network cable.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) Nonmetallic cable. This subsidiary record category shall include the original cost of optical fiber cable and... between buildings on one customer's same premises. Intrabuilding network cables are used to distribute...

7 CFR 1755.406 - Shield or armor ground resistance measurements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... or armor ground resistance measurements shall be made on completed lengths of copper cable and wire... measurement shall be made between the copper cable and wire shield and ground and between the fiber optic... instructions. (d) Applicable results. (1) For all new copper cable and wire facilities and all new fiber optic...

7 CFR 1755.406 - Shield or armor ground resistance measurements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... or armor ground resistance measurements shall be made on completed lengths of copper cable and wire... measurement shall be made between the copper cable and wire shield and ground and between the fiber optic... instructions. (d) Applicable results. (1) For all new copper cable and wire facilities and all new fiber optic...

7 CFR 1755.406 - Shield or armor ground resistance measurements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... or armor ground resistance measurements shall be made on completed lengths of copper cable and wire... measurement shall be made between the copper cable and wire shield and ground and between the fiber optic... instructions. (d) Applicable results. (1) For all new copper cable and wire facilities and all new fiber optic...

Fiber Optic Cable Thermal Preparation to Ensure Stable Operation

NASA Technical Reports Server (NTRS)

Thoames Jr, William J.; Chuska, Rick F.; LaRocca, Frank V.; Switzer, Robert C.; Macmurphy, Shawn L.; Ott, Melanie N.

2008-01-01

Fiber optic cables are widely used in modern systems that must provide stable operation during exposure to changing environmental conditions. For example, a fiber optic cable on a satellite may have to reliably function over a temperature range of -50 C up to 125 C. While the system requirements for a particular application will dictate the exact method by which the fibers should be prepared, this work will examine multiple ruggedized fibers prepared in different fashions and subjected to thermal qualification testing. The data show that if properly conditioned the fiber cables can provide stable operation, but if done incorrectly, they will have large fluctuations in transmission.

Distributed Fiber Optic Sensors for Earthquake Detection and Early Warning

NASA Astrophysics Data System (ADS)

Karrenbach, M. H.; Cole, S.

2016-12-01

Fiber optic cables placed along pipelines, roads or other infrastructure provide dense sampling of passing seismic wavefields. Laser interrogation units illuminate the fiber over its entire length, and strain at desired points along the fiber can be determined from the reflected signal. Single-mode optical fibers up to 50 km in length can provide a distributed acoustic sensing system (DAS) where the acoustic bandwidth of each channel is limited only by the round-trip time over the length of the cable (0.0005 s for a 50 km cable). Using a 10 m spatial resolution results in 4000 channels sampled at 2.5 kHz spanning a 40 km-long fiber deployed along a pipeline. The inline strain field is averaged along the fiber over a 10 m section of the cable at each desired spatial sample, creating a virtual sensor location. Typically, a dynamic strain sensitivity of sub-nanometers within each gauge along the entire length of the fiber can be achieved. This sensitivity corresponds to a particle displacement figure of approximately -90 dB ms-2Hz-½. Such a fiber optic sensor is not as sensitive as long-period seismometers used in earthquake networks, but given the large number of channels, small to medium-sized earthquakes can be detected, depending on distance from the array, and can be located with precision through arrival time inversions. We show several examples of earthquake recordings using distributed fiber optic arrays that were deployed originally for other purposes. A 480 km long section of a pipeline in Turkey was actively monitored with a DAS fiber optic system for activities in the immediate vicinity of the pipeline. The densely spaced sensor array along the pipeline detected earthquakes of 3.6 - 7.2 magnitude range, centered near Van, Turkey. Secondly, a fiber optic system located along a rail line near the Salton Sea in California was used to create a smaller scale fiber optic sensor array, on which earthquakes with magnitudes 2.2 - 2.7 were recorded from epicenters up to 65 km away. Our analysis shows that existing fiber optic installations along infrastructure could be combined to form a large aperture array with tens of thousands of channels for epicenter estimation and for early warning purposes, augmenting existing earthquake sensor networks.

Optical pin apparatus for measuring the arrival time and velocity of shock waves and particles

DOEpatents

Benjamin, R.F.

1983-10-18

An apparatus for the detection of the arrival and for the determination of the velocity of disturbances such as shock-wave fronts and/or projectiles. Optical pins using fluid-filled microballoons as the light source and an optical fiber as a link to a photodetector have been used to investigate shock-waves and projectiles. A microballoon filled with a noble gas is affixed to one end of a fiber-optic cable, and the other end of the cable is attached to a high-speed streak camera. As the shock-front or projectile compresses the microballoon, the gas inside is heated and compressed producing a bright flash of light. The flash of light is transmitted via the optic cable to the streak camera where it is recorded. One image-converter streak camera is capable of recording information from more than 100 microballoon-cable combinations simultaneously.

Optical pin apparatus for measuring the arrival time and velocity of shock waves and particles

DOEpatents

Benjamin, Robert F.

1987-01-01

An apparatus for the detection of the arrival and for the determination of the velocity of disturbances such as shock-wave fronts and/or projectiles. Optical pins using fluid-filled microballoons as the light source and an optical fiber as a link to a photodetector have been used to investigate shock-waves and projectiles. A microballoon filled with a noble gas is affixed to one end of a fiber-optic cable, and the other end of the cable is attached to a high-speed streak camera. As the shock-front or projectile compresses the microballoon, the gas inside is heated and compressed producing a bright flash of light. The flash of light is transmitted via the optic cable to the streak camera where it is recorded. One image-converter streak camera is capable of recording information from more than 100 microballoon-cable combinations simultaneously.

Optical pin apparatus for measuring the arrival time and velocity of shock waves and particles

DOEpatents

Benjamin, R.F.

1987-03-10

An apparatus is disclosed for the detection of the arrival and for the determination of the velocity of disturbances such as shock-wave fronts and/or projectiles. Optical pins using fluid-filled microballoons as the light source and an optical fiber as a link to a photodetector have been used to investigate shock-waves and projectiles. A microballoon filled with a noble gas is affixed to one end of a fiber-optic cable, and the other end of the cable is attached to a high-speed streak camera. As the shock-front or projectile compresses the microballoon, the gas inside is heated and compressed producing a bright flash of light. The flash of light is transmitted via the optic cable to the streak camera where it is recorded. One image-converter streak camera is capable of recording information from more than 100 microballoon-cable combinations simultaneously. 3 figs.

Local Area Networks.

ERIC Educational Resources Information Center

Marks, Kenneth E.; Nielsen, Steven

1991-01-01

Discusses cabling that is needed in local area networks (LANs). Types of cables that may be selected are described, including twisted pair, coaxial cables (or ethernet), and fiber optics; network topologies, the manner in which the cables are laid out, are considered; and cable installation issues are discussed. (LRW)

Unusual Attenuation Recovery Process After Fiber Optic Cable Irradiation

NASA Astrophysics Data System (ADS)

Konečná, Z.; Plaček, V.; Havránek, P.

2017-11-01

At present, the number of optical cables in nuclear power plants has been increasing. Fiber optic cables are commonly used at nuclear power plants in instrumentation and control systems but they are usually used in environments without radiation. Nevertheless, currently, the number of applications in NPP containment with radiation is increasing. One of the most prevalent effects of radiation exposure is an increase of signal attenuation (signal loss). This is the result of fiber darkening due to radiation exposure and it is the main limitation factor in application of fiber optics in radiation environment. However, after the irradiation, the fiber optics go through a “recovery process” during which the optical properties improve again; i.e. attenuation decreases. However, we have found cable, where the expected healing process after few days changed its trend and the attenuation increased again to a value well above the attenuation just after the irradiation. This paper describes experiments that were carried out to explain this unusual recovery behaviour.

Proceedings of the 48th International Wire and Cable Symposium (48th) Held in Atlantic City, New Jersey on 15-18 November 1999

DTIC Science & Technology

1999-11-18

telecommunications and data processing installations, Berlin Offenbach: vde - verlag 4. DIN EN 187000: Specification of optical fiber cables...Berlin Offenbach : vde - verlag 5. DIN EN 188000: Specification of optical fibers, Berlin Offenbach : vde - verlag 6. IEC 60793-1: Optical fibers, Part 1...subsystem of customer premises up to a frequency of 100 MHz. The technical requirements of these balanced cabling systems are defined in the standards EN

Visible-Near Infrared (VNIR) and Shortwave Infrared (SWIR) Spectral Variability of Urban Materials

DTIC Science & Technology

2013-03-01

extension). FieldSpec 4 spectrometer unit is contained in the backpack. The fiber optic cable and power cable for the contact probe are seen...spectroradiometer foreoptic (lens) is typically between 1 degree and 25 degrees when using natural lighting (or artificially lit in lab) but a bare fiber ... fiber optic cable and power cable for the contact probe are seen. In operation, the spectrometer is allowed to warm up prior to use for at least 30

Fiber optics for aircraft engine/inlet control

NASA Technical Reports Server (NTRS)

Baumbick, R. J.

1981-01-01

NASA programs that focus on the use of fiber optics for aircraft engine/inlet control are reviewed. Fiber optics for aircraft control is attractive because of its inherent immunity to EMI and RFI noise. Optical signals can be safely transmitted through areas that contain flammable or explosive materials. The use of optics also makes remote sensing feasible by eliminating the need for electrical wires to be connected between sensors and computers. Using low-level optical signals to control actuators is also feasible when power is generated at the actuator. Each application of fiber optics for aircraft control has different requirements for both the optical cables and the optical connectors. Sensors that measure position and speed by using slotted plates can use lossy cables and bundle connectors if data transfer is in the parallel mode. If position and speed signals are multiplexed, cable and connector requirements change. Other sensors that depend on changes in transmission through materials require dependable characteristics of both the optical cables and the optical connectors. A variety of sensor types are reviewed, including rotary position encoders, tachometers, temperature sensors, and blade tip clearance sensors for compressors and turbines. Research on a gallium arsenide photoswitch for optically switched actuators that operate at 250 C is also described.

30 CFR 7.402 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... wires not insulated from one another, suitable for carrying an electric current. Electric Cable. An assembly of one or more insulated conductors of electric current under a common or integral jacket. A cable... the primary electric current or power is transmitted. Signaling Cable. A fiber optic cable, or a cable...

30 CFR 7.402 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... wires not insulated from one another, suitable for carrying an electric current. Electric Cable. An assembly of one or more insulated conductors of electric current under a common or integral jacket. A cable... the primary electric current or power is transmitted. Signaling Cable. A fiber optic cable, or a cable...

30 CFR 7.402 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... wires not insulated from one another, suitable for carrying an electric current. Electric Cable. An assembly of one or more insulated conductors of electric current under a common or integral jacket. A cable... the primary electric current or power is transmitted. Signaling Cable. A fiber optic cable, or a cable...

A novel approach for studying submarine faults: the FOCUS project (FOCUS = Fiber Optic Cable Use for Seafloor studies of earthquake hazard and deformation)

NASA Astrophysics Data System (ADS)

Gutscher, M. A.; Royer, J. Y.; Graindorge, D.; Murphy, S.; Klingelhoefer, F.; Cattaneo, A.; Barreca, G.; Quetel, L.; Petersen, F.; Riccobene, G.; Urlaub, M.; Krastel, S.; Gross, F.; Kopp, H.

2017-12-01

Two-thirds of the earth's surface is covered by water and thus largely inaccessible to modern networks of seismological instruments. A novel use of fiber optic cables could help improve hazard assessment and increase early warning capability. Laser reflectometry using BOTDR (Brillouin Optical Time Domain Reflectometry), commonly used for structural health monitoring of large-scale engineering structures (e.g. - bridges, dams, pipelines, etc.) can measure very small strains (< 1 mm) at very large distances (10 - 200 km). This technique has never been used to monitor deformation caused by active faults on the seafloor. The objective of the FOCUS project is to demonstrate that this technique can measure small (1 - 2 cm) displacements on a primary test site offshore Sicily where the recently mapped North Alfeo Fault crosses the Catania EMSO seafloor observatory, 28 km long fiber optic cable. Two other EMSO test sites with fiber optic cables, the 100 km long Capo Passero (SE Sicily) and the 2 km long cable off Molene Island (W France) will also be studied. Initial reflectometry tests were performed on these three cables using a Febus BOTDR interrogator in June and July 2017. Unexpectedly high dynamic noise levels (corresponding to strains of 200 - 500 mm/m) were observed on the Molene cable, likely due to the high-energy, shallow water, open ocean environment. The tests on the EMSO infrastructure in Sicily indicated low experimental noise levels (20 - 30 mm/m) out to a distance of 15 km. BOTDR observations will have to be calibrated by other independent measurements. Therefore, targeted marine geophysical surveys of the seafloor along the trace of the cable and faults are planned, with the use of seafloor geodetic instruments to quantify fault displacement. Once the BOTDR fault-monitoring technique has been tested, demonstrated and calibrated offshore Eastern Sicily, the goal is to expand it to other fiber optic cable networks, either existing research networks in earthquake hazard zones (Japan, Cascadia) or to the Mediterranean region through access to retired (decommissioned) telecommunication cables or development of dual-use cables (two of the anticipated outcomes of the FOCUS project). This represents a potentially tremendous breakthrough in seismology, tectonics and natural hazard early warning capability.

State-of-the-art fiber optics for short distance frequency reference distribution

NASA Astrophysics Data System (ADS)

Lutes, G. F.; Primas, L. E.

1989-05-01

A number of recently developed fiber-optic components that hold the promise of unprecedented stability for passively stabilized frequency distribution links are characterized. These components include a fiber-optic transmitter, an optical isolator, and a new type of fiber-optic cable. A novel laser transmitter exhibits extremely low sensitivity to intensity and polarization changes of reflected light due to cable flexure. This virtually eliminates one of the shortcomings in previous laser transmitters. A high-isolation, low-loss optical isolator has been developed which also virtually eliminates laser sensitivity to changes in intensity and polarization of reflected light. A newly developed fiber has been tested. This fiber has a thermal coefficient of delay of less than 0.5 parts per million per deg C, nearly 20 times lower than the best coaxial hardline cable and 10 times lower than any previous fiber-optic cable. These components are highly suitable for distribution systems with short extent, such as within a Deep Space Communications Complex. Here, these new components are described and the test results presented.

State-of-the-art fiber optics for short distance frequency reference distribution

NASA Technical Reports Server (NTRS)

Lutes, G. F.; Primas, L. E.

1989-01-01

A number of recently developed fiber-optic components that hold the promise of unprecedented stability for passively stabilized frequency distribution links are characterized. These components include a fiber-optic transmitter, an optical isolator, and a new type of fiber-optic cable. A novel laser transmitter exhibits extremely low sensitivity to intensity and polarization changes of reflected light due to cable flexure. This virtually eliminates one of the shortcomings in previous laser transmitters. A high-isolation, low-loss optical isolator has been developed which also virtually eliminates laser sensitivity to changes in intensity and polarization of reflected light. A newly developed fiber has been tested. This fiber has a thermal coefficient of delay of less than 0.5 parts per million per deg C, nearly 20 times lower than the best coaxial hardline cable and 10 times lower than any previous fiber-optic cable. These components are highly suitable for distribution systems with short extent, such as within a Deep Space Communications Complex. Here, these new components are described and the test results presented.

Strain distribution in thin concrete pavement panels under three-point loading to failure with pre-pulse-pump Brillouin optical time domain analysis (Presentation Video)

NASA Astrophysics Data System (ADS)

Bao, Yi; Cain, John; Chen, Yizheng; Huang, Ying; Chen, Genda; Palek, Leonard

2015-04-01

Thin concrete panels reinforced with alloy polymer macro-synthetic fibers have recently been introduced to rapidly and cost-effectively improve the driving condition of existing roadways by laying down a fabric sheet on the roadways, casting a thin layer of concrete, and then cutting the layer into panels. This study is aimed to understand the strain distribution and potential crack development of concrete panels under three-point loading. To this end, six full-size 6ft×6ft×3in concrete panels were tested to failure in the laboratory. They were instrumented with three types of single-mode optical fiber sensors whose performance and ability to measure the strain distribution and detect cracks were compared. Each optical fiber sensor was spliced and calibrated, and then attached to a fabric sheet using adhesive. A thin layer of mortar (0.25 ~ 0.5 in thick) was cast on the fabric sheet. The three types of distributed sensors were bare SM-28e+ fiber, SM-28e+ fiber with a tight buffer, and concrete crack cable, respectively. The concrete crack cable consisted of one SM-28e+ optical fiber with a tight buffer, one SM-28e+ optical fiber with a loose buffer for temperature compensation, and an outside protective tight sheath. Distributed strains were collected from the three optical fiber sensors with pre-pulse-pump Brillouin optical time domain analysis in room temperature. Among the three sensors, the bare fiber was observed to be most fragile during construction and operation, but most sensitive to strain change or micro-cracks. The concrete crack cable was most rugged, but not as sensitive to micro-cracks and robust in micro-crack measurement as the bare fiber. The ruggedness and sensitivity of the fiber with a tight buffer were in between the bare fiber and the concrete crack cable. The strain distribution resulted from the three optical sensors are in good agreement, and can be applied to successfully locate cracks in the concrete panels. It was observed that the three types of fibers were functional until the concrete panels have experienced inelastic deformation, making the distributed strain sensing technology promising for real applications in pavement engineering.

FY-79 - development of fiber optics connector technology for large space systems

NASA Technical Reports Server (NTRS)

Campbell, T. G.

1980-01-01

The development of physical concepts for integrating fiber optic connectors and cables with structural concepts proposed for the LSST is discussed. Emphasis is placed on remote connections using integrated cables.

77 FR 28353 - Foreign-Trade Zone 45-Portland, OR, Notification of Proposed Production Activity, Shimadzu USA...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-14

...; filter paper; technical books and manuals; textile-covered foam shielding; ceramic hardware and fittings... cables (including fiber optic cable); insulators; filters; lenses; mirrors; prisms; other optical...

Non-perturbing voltage measurement in a coaxial cable with slab-coupled optical sensors.

PubMed

Stan, Nikola; Seng, Frederick; Shumway, LeGrand; King, Rex; Schultz, Stephen

2017-08-20

Voltage in a coaxial cable is measured by an electric-field optical fiber sensor exploiting the proportionality of voltage and electric field in a fixed structure. The sensor is inserted in a hole drilled through the dielectric of the RG-218 coaxial cable and sealed with epoxy to displace all air and prevent the adverse effects of charge buildup during high-voltage measurements. It is shown that the presence of the sensor in the coaxial cable does not significantly increase electrical reflections in the cable. A slab-coupled optical fiber sensor (SCOS) is used for its compact size and dielectric make. The dynamic range of 50 dB is shown experimentally with detection of signals as low as 1 V and up to 157 kV. A low corner of 0.3 Hz is demonstrated and the SCOS is shown to be able to measure 90 ns rise time.

Using passive fiber-optic distributed temperature sensing to estimate soil water content at a discontinuous permafrost site

NASA Astrophysics Data System (ADS)

Wagner, A. M.; Lindsey, N.; Ajo Franklin, J. B.; Gelvin, A.; Saari, S.; Ekblaw, I.; Ulrich, C.; Dou, S.; James, S. R.; Martin, E. R.; Freifeld, B. M.; Bjella, K.; Daley, T. M.

2016-12-01

We present preliminary results from an experimental study targeting the use of passive fiber-optic distributed temperature sensing (DTS) in a variety of geometries to estimate moisture content evolution in a dynamic permafrost system. A 4 km continuous 2D array of multi-component fiber optic cable (6 SM/6 MM) was buried at the Fairbanks Permafrost Experiment Station to investigate the possibility of using fiber optic distributed sensing as an early detection system for permafrost thaw. A heating experiment using 120 60 Watt heaters was conducted in a 140 m2 area to artificially thaw the topmost section of permafrost. The soils at the site are primarily silt but some disturbed areas include backfilled gravel to depths of approximately 1.0 m. Where permafrost exists, the depth to permafrost ranges from 1.5 to approximately 5 m. The experiment was also used to spatially estimate soil water content distribution throughout the fiber optic array. The horizontal fiber optic cable was buried at depths between 10 and 20 cm. Soil temperatures were monitored with a DTS system at 25 cm increments along the length of the fiber. At five locations, soil water content time-domain reflectometer (TDR) probes were also installed at two depths, in line with the fiber optic cable and 15 to 25 cm below the cable. The moisture content along the fiber optic array was estimated using diurnal effects from the dual depth temperature measurements. In addition to the horizontally installed fiber optic cable, vertical lines of fiber optic cable were also installed inside and outside the heater plot to a depth of 10 m in small diameter (2 cm) boreholes. These arrays were installed in conjunction with thermistor strings and are used to monitor the thawing process and to cross correlate with soil temperatures at the depth of the TDR probes. Results will be presented from the initiation of the artificial thawing through subsequent freeze-up. A comparison of the DTS measured temperatures and thermistors in vertically installed PVC pipes will also be shown. Initial results from a thermal model of the artificial heating experiment and the model's correlation to the actual soil temperature measurements will also be presented. These results show the possibility of using fiber optic cable to measure moisture contents along a longer array with only limited control points.

Complete Fiber/Copper Cable Solution for Long-Term Temperature and Pressure Measurement in Supercritical Reservoirs and EGS Wells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pastouret, Alan; Gooijer, Frans; Overton, Bob

High Temperature insulated wire and optical fiber cable is a key enabling technology for the Geothermal Technologies Program (GTP). Without insulated electrical wires and optical fiber, downhole temperature and pressure sensors, flow meters and gauges cannot communicate with the surface. Unfortunately, there are currently no insulated electrical wire or fiber cable constructions capable of surviving for extended periods of deployment in a geothermal well (240-325°C) or supercritical (374°C) reservoir. This has severely hindered engineered reservoir creation, management and utilization, as hot zones and cool water intrusions cannot be understood over time. The lack of a insulated electrical wire and fibermore » cable solution is a fundamental limitation to the viability of this energy source. The High Temperature Downhole Tools target specification is development of tools and sensors for logging and monitoring wellbore conditions at depths of up to 10,000 meters and temperatures up to 374oC. It well recognized in the industry that no current electronic or fiber cable can be successfully deployed in a well and function successfully for more a few days at temperatures over 240oC. The goal of this project was to raise this performance level significantly. Prysmian Group’s objective in this project was to develop a complete, multi-purpose cable solution for long-term deployment in geothermal wells/reservoirs that can be used with the widest variety of sensors. In particular, the overall project objective was to produce a manufacturable cable design that can perform without serious degradation: • At temperatures up to 374°C; • At pressures up to 220 bar; • In a hydrogen-rich environment; and • For the life of the well (> 5 years). This cable incorporates: • Specialty optical fibers, with specific glass chemistry and high temperature and pressure protective coatings for data communication and distributed temperature and pressure sensing, and • High-temperature insulated wire conductors Prysmian Group has developed a geothermal fiber optic cable (GFOC) solution which incorporates novel glass chemistry for optical fibers to operate at the required bandwidths in high temperature/high pressure hydrogen rich environments with fiber protection, high temperature insulated conductors and protective cladding for cable components. The cable solution has been tested in a geothermal installation for 10 months. The electrical insulation and optical fibers have been validated through laboratory testing to ensure successful operation for greater than 5 years at 300°C, with the possibility of higher temperatures depending on the particular well environment. With the 300°C optical fiber and electrical insulation developments completed and validated in laboratory tests the greatest challenge to a complete 300°C cable solution was protecting the optical fibers in the cable. Optical fibers are typically incased in a protective tube where the tube is filled with a gel. The gel serves as mechanical protection, prevent moisture ingress, and can include hydrogen scavenging materials. A suitable gel for use at 300°C could not be identified and an industrialized alternative was not fully attained. Despite the problems encountered and the lower long-term operating temperature of the cable solution, the project showed success in developing a complete cable solution for a large portion of the geothermal wells in operation today. Further work to obtain the higher long-term temperature goal of the project can be achieved based on the knowledge gained in the current project. This project is significant for many reasons including the new materials science, manufacturing technology, energy independence, and jobs created and will create.« less

Effect of Concrete Creep on the displacement of single tower single cable plane Extradosed Cable-stayed Bridge

NASA Astrophysics Data System (ADS)

Shi, Jing-xian; Ran, Zhi-hong

2018-03-01

Extradossed Cable-stayed Bridge is both cable-stayed Bridge and Continuous rigid frame bridge mechanics feature, Beam is the main force components, cable is supplement.This article combined with a single tower and single cable plane Extradossed cable-stayed bridge in Yunnan, use different creep calculation models and analysis deflection caused by creep effects. The results showing that deflection caused by creep effect is smaller than the same span continuous rigid frame bridge, the value is about 2cm. On the other hand the deflection is increasing with ambient humidity decreases, therefore in the dry environment the calculation model is relatively large in the pre-camber. In the choice of RC creep model is significant in the dry areas.

An optimal method for producing low-stress fibre optic cables for astronomy

NASA Astrophysics Data System (ADS)

Murray, Graham; Tamura, Naoyuki; Takato, Naruhisa; Ekpenyong, Paul; Jenkins, Daniel; Leeson, Kim; Trezise, Shaun; Butterley, Timothy; Gunn, James; Ferreira, Decio; Oliveira, Ligia; Sodre, Laerte

2017-09-01

An increasing number of astronomical spectrographs employ optical fibres to collect and deliver light. For integral-field and high multiplex multi-object survey instruments, fibres offer unique flexibility in instrument design by enabling spectrographs to be located remotely from the telescope focal plane where the fibre inputs are deployed. Photon-starved astronomical observations demand optimum efficiency from the fibre system. In addition to intrinsic absorption loss in optical fibres, another loss mechanism, so-called focal ratio degradation (FRD) must be considered. A fundamental cause of FRD is stress, therefore low stress fibre cables that impart minimum FRD are essential. The FMOS fibre instrument for Subaru Telescope employed a highly effective cable solution developed at Durham University. The method has been applied again for the PFS project, this time in collaboration with a company, PPC Broadband Ltd. The process, planetary stranding, is adapted from the manufacture of large fibre-count, large diameter marine telecommunications cables. Fibre bundles describe helical paths through the cable, incorporating additional fibre per unit length. As a consequence fibre stress from tension and bend-induced `race-tracking' is minimised. In this paper stranding principles are explained, covering the fundamentals of stranded cable design. The authors describe the evolution of the stranding production line and the numerous steps in the manufacture of the PFS prototype cable. The results of optical verification tests are presented for each stage of cable production, confirming that the PFS prototype performs exceptionally well. The paper concludes with an outline of future on-telescope test plans.

Total radiated power, infrared output, and heat generation by cold light sources at the distal end of endoscopes and fiber optic bundle of light cables.

PubMed

Hensman, C; Hanna, G B; Drew, T; Moseley, H; Cuschieri, A

1998-04-01

Skin burns and ignition of drapes have been reported with the use of cold light sources. The aim of the study was to document the temperature generated by cold light sources and to correlate this with the total radiated power and infrared output. The temperature, total radiated power, and infrared output were measured as a function of time at the end of the endoscope (which is inserted into the operative field) and the end of the fiber optic bundle of the light cable (which connects the cable to the light port of the endoscope) using halogen and xenon light sources. The highest temperature recorded at the end of the endoscope was 95 degrees C. The temperature measured at the optical fiber location of the endoscope was higher than at its lens surface (p < 0.0001). At the end of the fiber optic bundle of light cables, the temperature reached 225 degrees C within 15 s. The temperature recorded at the optical fiber location of all endoscopes and light cables studied rose significantly over a period of 10 min to reach its maximum (p <0.0001) and then leveled off for the duration of the study (30 min). The infrared output accounted only for 10% of the total radiated power. High temperatures are reached by 10 min at the end of fiber optic bundle of light cables and endoscopes with both halogen and xenon light sources. This heat generation is largely due to the radiated power in the visible light spectrum.

Flight testing of a fiber optic temperature sensor

NASA Technical Reports Server (NTRS)

Finney, M. J.; Tregay, G. W.; Calabrese, P. R.

1993-01-01

A fiber optic temperature sensor (FOTS) system consisting of an optical probe, a flexible fiber optic cable, and an electro-optic signal processor was fabricated to measure the gas temperature in a turbine engine. The optical probe contained an emissive source embedded in a sapphire lightguide coupled to a fiber-optic jumper cable and was retrofitted into an existing thermocouple probe housing. The flexible fiber optic cable was constructed with 200 micron core, polyimide-coated fiber and was ruggedized for an aircraft environment. The electro-optic signal processing unit was used to ratio the intensities of two wavelength intervals and provided an analog output value of the indicated temperature. Subsequently, this optical sensor system was installed on a NASA Dryden F-15 Highly Integrated Digital Electronic Control (HIDEC) Aircraft Engine and several flight tests were conducted. Over the course of flight testing, the FOTS system's response was proportional to the average of the existing thermocouples sensing the changes in turbine engine thermal conditions.

29 CFR 1910.331 - Scope.

Code of Federal Regulations, 2013 CFR

2013-07-01

... wiring. Installations of other outside conductors on the premises. (4) Optical fiber cable. Installations of optical fiber cable where such installations are made along with electric conductors. Note: See... of utilization equipment used for purposes other than generating, transmitting, or distributing...

29 CFR 1910.331 - Scope.

Code of Federal Regulations, 2014 CFR

2014-07-01

... wiring. Installations of other outside conductors on the premises. (4) Optical fiber cable. Installations of optical fiber cable where such installations are made along with electric conductors. Note: See... of utilization equipment used for purposes other than generating, transmitting, or distributing...

7 CFR 1755.901 - Incorporation by Reference.

Code of Federal Regulations, 2011 CFR

2011-01-01

..., Digital Systems and Networks, Transmission media characteristics—Optical fibre cables, Characteristics of... Systems and Media, Digital Systems and Networks, Transmission media characteristics—Optical fibre cables... National Archives and Records Administration (NARA). For information on the availability of these materials...

Fiber Coupled Laser Diodes with Even Illumination Pattern

NASA Technical Reports Server (NTRS)

Howard, Richard T. (Inventor)

2007-01-01

An optical fiber for evenly illuminating a target. The optical fiber is coupled to a laser emitting diode and receives laser light. The la ser light travels through the fiber optic and exits at an exit end. T he exit end has a diffractive optical pattern formed thereon via etch ing, molding or cutting, to reduce the Gaussian profile present in co nventional fiber optic cables The reduction of the Gaussian provides an even illumination from the fiber optic cable.

Optical fiber cable chemical stripping fixture

NASA Technical Reports Server (NTRS)

Kolasinski, John R. (Inventor); Coleman, Alexander M. (Inventor)

1995-01-01

An elongated fixture handle member is connected to a fixture body member with both members having interconnecting longitudinal central axial bores for the passage of an optical cable therethrough. The axial bore of the fixture body member, however, terminates in a shoulder stop for the outer end of a jacket of the optical cable covering both an optical fiber and a coating therefor, with an axial bore of reduced diameter continuing from the shoulder stop forward for a predetermined desired length to the outer end of the fixture body member. A subsequent insertion of the fixture body member including the above optical fiber elements into a chemical stripping solution results in a softening of the exposed external coating thereat which permits easy removal thereof from the optical fiber while leaving a desired length coated fiber intact within the fixture body member.

Field test of optical and electrical fire detectors in simulated fire scenes in a cable tunnel

NASA Astrophysics Data System (ADS)

Fan, Dian; Ding, Hongjun; Wang, Dorothy Y.; Jiang, Desheng

2014-06-01

This paper presents the testing results of three types of fire detectors: electrical heat sensing cable, optical fiber Raman temperature sensing detector, and optical fiber Bragg grating (FBG) temperature sensing detector, in two simulated fire scenes in a cable tunnel. In the small-scale fire with limited thermal radiation and no flame, the fire alarm only comes from the heat sensors which directly contact with the heat source. In the large-scale fire with about 5 °C/min temperature rising speed within a 3-m span, the fire alarm response time of the fiber Raman sensor and FBG sensors was about 30 seconds. The test results can be further used for formulating regulation for early fire detection in cable tunnels.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kertzscher, G; Beddar, S

Purpose: To study the promising potential of inorganic scintillator detectors (ISDs) and investigate various unwanted luminescence properties which may compromise their accuracy. Methods: The ISDs were comprised of a ruby crystal coupled to a polymethyl methacrylate (PMMA) fiber-optic cable and a charged coupled device camera. A new type of ISD was manufactured and included a long-pass filter that was sandwiched between the crystal and the fiber-optic cable. The purpose of the filter was to suppress the Cerenkov and fluorescence background light induced in the PMMA (the stem signal) from striking the ruby crystal, generating unwanted ruby excitation. A variety ofmore » experiments were performed to characterize the ruby based ISDs. The relative contribution of the induced ruby signal and the stem signal were quantified while exposing the detector and a bare fiber-optic cable to a high dose rate (HDR) brachytherapy (BT) source, respectively. The unwanted ruby excitation was quantified while irradiating the fiber-optic cable with the detector volume shielded. Other experiments addressed time-dependent luminescence properties and a comparison to other commonly used organic scintillator detectors (BCF-12, BCF-60). Results: When the BT source dwelled 0.5 cm away from the fiber-optic cable, the unwanted ruby excitation amounted to >5% of the total signal if the source-distance from the scintillator was >7 cm. However, the unwanted excitation was suppressed to <1% if the ISD incorporated an optic filter. The stem signal was suppressed with a 20 nm band-pass filter and was <3% as long as the source-distance was <7 cm. The ruby based ISDs generated signal up to 20(40) times that of BCF-12(BCF-60). Conclusion: The study presents solutions to unwanted luminescence properties of ruby based ISDs for HDR BT. An optic filter should be sandwiched between the scintillator volume and the fiber-optic cable to prevent the stem signal to excite the ruby crystal.« less

Optical fibers for the distribution of frequency and timing references

NASA Technical Reports Server (NTRS)

Lutes, G. F.

1981-01-01

An optical fiber communications link was installed for the purpose of evaluating the applicability of optical fiber technology to the distribution of frequency and timing reference signals. It incorporated a 1.5km length of optical fiber cable containing two multimode optical fibers. The two fibers were welded together at one end of the cable to attain a path length of 3km. Preliminary measurements made on this link, including Allan variance and power spectral density of phase noise are reported.

High Speed and High Spatial Density Parameter Measurement Using Fiber Optic Sensing Technology

NASA Technical Reports Server (NTRS)

Richards, William Lance (Inventor); Piazza, Anthony (Inventor); Parker, Allen R. Jr. (Inventor); Hamory, Philip J (Inventor); Chan, Hon Man (Inventor)

2017-01-01

The present invention is an improved fiber optic sensing system (FOSS) having the ability to provide both high spatial resolution and high frequency strain measurements. The inventive hybrid FOSS fiber combines sensors from high acquisition speed and low spatial resolution Wavelength-Division Multiplexing (WDM) systems and from low acquisition speed and high spatial resolution Optical Frequency Domain Reflection (OFDR) systems. Two unique light sources utilizing different wavelengths are coupled with the hybrid FOSS fiber to generate reflected data from both the WDM sensors and OFDR sensors operating on a single fiber optic cable without incurring interference from one another. The two data sets are then de-multiplexed for analysis, optionally with conventionally-available WDM and OFDR system analyzers.

Diagnostic system for measuring temperature, pressure, CO2 concentration and H2O concentration in a fluid stream

DOE Office of Scientific and Technical Information (OSTI.GOV)

Partridge, Jr., William P.; Jatana, Gurneesh Singh; Yoo, Ji-Hyung

A diagnostic system for measuring temperature, pressure, CO.sub.2 concentration and H.sub.2O concentration in a fluid stream is described. The system may include one or more probes that sample the fluid stream spatially, temporally and over ranges of pressure and temperature. Laser light sources are directed down pitch optical cables, through a lens and to a mirror, where the light sources are reflected back, through the lens to catch optical cables. The light travels through the catch optical cables to detectors, which provide electrical signals to a processer. The processer utilizes the signals to calculate CO.sub.2 concentration based on the temperaturesmore » derived from H.sub.2O vapor concentration. A probe for sampling CO.sub.2 and H.sub.2O vapor concentrations is also disclosed. Various mechanical features interact together to ensure the pitch and catch optical cables are properly aligned with the lens during assembly and use.« less

Diagnostic system for measuring temperature, pressure, CO.sub.2 concentration and H.sub.2O concentration in a fluid stream

DOE Office of Scientific and Technical Information (OSTI.GOV)

Partridge, Jr., William P.; Jatana, Gurneesh Singh; Yoo, Ji Hyung

A diagnostic system for measuring temperature, pressure, CO.sub.2 concentration and H.sub.2O concentration in a fluid stream is described. The system may include one or more probes that sample the fluid stream spatially, temporally and over ranges of pressure and temperature. Laser light sources are directed down pitch optical cables, through a lens and to a mirror, where the light sources are reflected back, through the lens to catch optical cables. The light travels through the catch optical cables to detectors, which provide electrical signals to a processer. The processer utilizes the signals to calculate CO.sub.2 concentration based on the temperaturesmore » derived from H.sub.2O vapor concentration. A probe for sampling CO.sub.2 and H.sub.2O vapor concentrations is also disclosed. Various mechanical features interact together to ensure the pitch and catch optical cables are properly aligned with the lens during assembly and use.« less

Mapping variability of soil water content and flux across 1-1000 m scales using the Actively Heated Fiber Optic method

NASA Astrophysics Data System (ADS)

Sayde, Chadi; Buelga, Javier Benitez; Rodriguez-Sinobas, Leonor; El Khoury, Laureine; English, Marshall; van de Giesen, Nick; Selker, John S.

2014-09-01

The Actively Heated Fiber Optic (AHFO) method is shown to be capable of measuring soil water content several times per hour at 0.25 m spacing along cables of multiple kilometers in length. AHFO is based on distributed temperature sensing (DTS) observation of the heating and cooling of a buried fiber-optic cable resulting from an electrical impulse of energy delivered from the steel cable jacket. The results presented were collected from 750 m of cable buried in three 240 m colocated transects at 30, 60, and 90 cm depths in an agricultural field under center pivot irrigation. The calibration curve relating soil water content to the thermal response of the soil to a heat pulse of 10 W m-1 for 1 min duration was developed in the lab. This calibration was found applicable to the 30 and 60 cm depth cables, while the 90 cm depth cable illustrated the challenges presented by soil heterogeneity for this technique. This method was used to map with high resolution the variability of soil water content and fluxes induced by the nonuniformity of water application at the surface.

Measurement of the temperature distribution inside the power cable using distributed temperature system

NASA Astrophysics Data System (ADS)

Jaros, Jakub; Liner, Andrej; Papes, Martin; Vasinek, Vladimir; Mach, Veleslav; Hruby, David; Kajnar, Tomas; Perecar, Frantisek

2015-01-01

Nowadays, the power cables are manufactured to fulfill the following condition - the highest allowable temperature of the cable during normal operation and the maximum allowable temperature at short circuit conditions cannot exceed the condition of the maximum allowable internal temperature. The distribution of the electric current through the conductor leads to the increase of the amplitude of electrons in the crystal lattice of the cables material. The consequence of this phenomenon is the increase of friction and the increase of collisions between particles inside the material, which causes the temperature increase of the carrying elements. The temperature increase is unwanted phenomena, because it is causing losses. In extreme cases, the long-term overload leads to the cable damaging or fire. This paper deals with the temperature distribution measurement inside the power cables using distributed temperature system. With cooperation with Kabex company, the tube containing optical fibers was installed into the center of power cables. These fibers, except telecommunications purposes, can be also used as sensors in measurements carrying out with distributed temperature system. These systems use the optical fiber as a sensor and allow the continual measurement of the temperature along the whole cable in real time with spatial resolution 1 m. DTS systems are successfully deployed in temperature measurement applications in industry areas yet. These areas include construction, drainage, hot water etc. Their advantages are low cost, resistance to electromagnetic radiation and the possibility of real time monitoring at the distance of 8 km. The location of the optical fiber in the center of the power cable allows the measurement of internal distribution of the temperature during overloading the cable. This measurement method can be also used for prediction of short-circuit and its exact location.

Square-lashing technique in segmental spinal instrumentation: a biomechanical study.

PubMed

Arlet, Vincent; Draxinger, Kevin; Beckman, Lorne; Steffen, Thomas

2006-07-01

Sublaminar wires have been used for many years for segmental spinal instrumentation in scoliosis surgery. More recently, stainless steel wires have been replaced by titanium cables. However, in rigid scoliotic curves, sublaminar wires or simple cables can either brake or pull out. The square-lashing technique was devised to avoid complications such as cable breakage or lamina cutout. The purpose of the study was therefore to test biomechanically the pull out and failure mode of simple sublaminar constructs versus the square-lashing technique. Individual vertebrae were subjected to pullout testing having one of two different constructs (single loop and square lashing) using either monofilament wire or multifilament cables. Four different methods of fixation were therefore tested: single wire construct, square-lashing wiring construct, single cable construct, and square-lashing cable construct. Ultimate failure load and failure mechanism were recorded. For the single wire the construct failed 12/16 times by wire breakage with an average ultimate failure load of 793 N. For the square-lashing wire the construct failed with pedicle fracture in 14/16, one bilateral lamina fracture, and one wire breakage. Ultimate failure load average was 1,239 N For the single cable the construct failed 12/16 times due to cable breakage (average force 1,162 N). 10/12 of these breakages were where the cable looped over the rod. For the square-lashing cable all of these constructs (16/16) failed by fracture of the pedicle with an average ultimate failure load of 1,388 N. The square-lashing construct had a higher pullout strength than the single loop and almost no cutting out from the lamina. The square-lashing technique with cables may therefore represent a new advance in segmental spinal instrumentation.

Fiber optic interconnect and optoelectronic packaging challenges for future generation avionics

NASA Astrophysics Data System (ADS)

Beranek, Mark W.

2007-02-01

Forecasting avionics industry fiber optic interconnect and optoelectronic packaging challenges that lie ahead first requires an assumption that military avionics architectures will evolve from today's centralized/unified concept based on gigabit laser, optical-to-electrical-to-optical switching and optical backplane technology, to a future federated/distributed or centralized/unified concept based on gigabit tunable laser, electro-optical switch and add-drop wavelength division multiplexing (WDM) technology. The requirement to incorporate avionics optical built-in test (BIT) in military avionics fiber optic systems is also assumed to be correct. Taking these assumptions further indicates that future avionics systems engineering will use WDM technology combined with photonic circuit integration and advanced packaging to form the technical basis of the next generation military avionics onboard local area network (LAN). Following this theme, fiber optic cable plants will evolve from today's multimode interconnect solution to a single mode interconnect solution that is highly installable, maintainable, reliable and supportable. Ultimately optical BIT for fiber optic fault detection and isolation will be incorporated as an integral part of a total WDM-based avionics LAN solution. Cost-efficient single mode active and passive photonic component integration and packaging integration is needed to enable reliable operation in the harsh military avionics application environment. Rugged multimode fiber-based transmitters and receivers (transceivers) with in-package optical BIT capability are also needed to enable fully BIT capable single-wavelength fiber optic links on both legacy and future aerospace platforms.

The Need for US Coast Guard Underwater Mission Development

DTIC Science & Technology

2013-04-23

vehicles and proliferation of fiber optic cables, raising the level of human interactions in the underwater environment. Besides the benefits from the...unmanned underwater vehicles, proliferation of fiber optic cables, and observation posts on the ocean floor will raise the level of human interactions...world’s demand for wood grows.39 As technology progresses, undersea infrastructure will continue to expand. Already, underwater fiber optic communication

Ruby-based inorganic scintillation detectors for 192Ir brachytherapy

NASA Astrophysics Data System (ADS)

Kertzscher, Gustavo; Beddar, Sam

2016-11-01

We tested the potential of ruby inorganic scintillation detectors (ISDs) for use in brachytherapy and investigated various unwanted luminescence properties that may compromise their accuracy. The ISDs were composed of a ruby crystal coupled to a poly(methyl methacrylate) fiber-optic cable and a charge-coupled device camera. The ISD also included a long-pass filter that was sandwiched between the ruby crystal and the fiber-optic cable. The long-pass filter prevented the Cerenkov and fluorescence background light (stem signal) induced in the fiber-optic cable from striking the ruby crystal, which generates unwanted photoluminescence rather than the desired radioluminescence. The relative contributions of the radioluminescence signal and the stem signal were quantified by exposing the ruby detectors to a high-dose-rate brachytherapy source. The photoluminescence signal was quantified by irradiating the fiber-optic cable with the detector volume shielded. Other experiments addressed time-dependent luminescence properties and compared the ISDs to commonly used organic scintillator detectors (BCF-12, BCF-60). When the brachytherapy source dwelled 0.5 cm away from the fiber-optic cable, the unwanted photoluminescence was reduced from  >5% to  <1% of the total signal as long as the ISD incorporated the long-pass filter. The stem signal was suppressed with a band-pass filter and was  <3% as long as the source distance from the scintillator was  <7 cm. Some ruby crystals exhibited time-dependent luminescence properties that altered the ruby signal by  >5% within 10 s from the onset of irradiation and after the source had retracted. The ruby-based ISDs generated signals of up to 20 times that of BCF-12-based detectors. The study presents solutions to unwanted luminescence properties of ruby-based ISDs for high-dose-rate brachytherapy. An optic filter should be sandwiched between the ruby crystal and the fiber-optic cable to suppress the photoluminescence. Furthermore, we recommend avoiding ruby crystals that exhibit significant time-dependent luminescence.

Ruby-based inorganic scintillation detectors for 192Ir brachytherapy

PubMed Central

Kertzscher, Gustavo; Beddar, Sam

2016-01-01

We tested the potential of ruby inorganic scintillation detectors (ISDs) for use in brachytherapy and investigated various unwanted luminescence properties that may compromise their accuracy. The ISDs were composed of a ruby crystal coupled to a poly(methyl methacrylate) fiber-optic cable and a charge-coupled device camera. The ISD also included a long-pass filter that was sandwiched between the ruby crystal and the fiber-optic cable. The long-pass filter prevented the Cerenkov and fluorescence background light (stem signal) induced in the fiber-optic cable from striking the ruby crystal, which generates unwanted photoluminescence rather than the desired radioluminescence. The relative contributions of the radioluminescence signal and the stem signal were quantified by exposing the ruby detectors to a high-dose-rate brachytherapy source. The photoluminescence signal was quantified by irradiating the fiber-optic cable with the detector volume shielded. Other experiments addressed time-dependent luminescence properties and compared the ISDs to commonly used organic scintillator detectors (BCF-12, BCF-60). When the brachytherapy source dwelled 0.5 cm away from the fiber-optic cable, the unwanted photoluminescence was reduced from > 5% to < 1% of the total signal as long as the ISD incorporated the long-pass filter. The stem signal was suppressed with a band-pass filter and was < 3% as long as the source distance from the scintillator was < 7 cm. Some ruby crystals exhibited time-dependent luminescence properties that altered the ruby signal by > 5% within 10 s from the onset of irradiation and after the source had retracted. The ruby-based ISDs generated signals of up to 20 times that of BCF-12-based detectors. The study presents solutions to unwanted luminescence properties of ruby-based ISDs for high-dose-rate brachytherapy. An optic filter should be sandwiched between the ruby crystal and the fiber-optic cable to suppress the photoluminescence. Furthermore, we recommend avoiding ruby crystals that exhibit significant time-dependent luminescence. PMID:27740947

Ruby-based inorganic scintillation detectors for 192Ir brachytherapy.

PubMed

Kertzscher, Gustavo; Beddar, Sam

2016-11-07

We tested the potential of ruby inorganic scintillation detectors (ISDs) for use in brachytherapy and investigated various unwanted luminescence properties that may compromise their accuracy. The ISDs were composed of a ruby crystal coupled to a poly(methyl methacrylate) fiber-optic cable and a charge-coupled device camera. The ISD also included a long-pass filter that was sandwiched between the ruby crystal and the fiber-optic cable. The long-pass filter prevented the Cerenkov and fluorescence background light (stem signal) induced in the fiber-optic cable from striking the ruby crystal, which generates unwanted photoluminescence rather than the desired radioluminescence. The relative contributions of the radioluminescence signal and the stem signal were quantified by exposing the ruby detectors to a high-dose-rate brachytherapy source. The photoluminescence signal was quantified by irradiating the fiber-optic cable with the detector volume shielded. Other experiments addressed time-dependent luminescence properties and compared the ISDs to commonly used organic scintillator detectors (BCF-12, BCF-60). When the brachytherapy source dwelled 0.5 cm away from the fiber-optic cable, the unwanted photoluminescence was reduced from  >5% to  <1% of the total signal as long as the ISD incorporated the long-pass filter. The stem signal was suppressed with a band-pass filter and was  <3% as long as the source distance from the scintillator was  <7 cm. Some ruby crystals exhibited time-dependent luminescence properties that altered the ruby signal by  >5% within 10 s from the onset of irradiation and after the source had retracted. The ruby-based ISDs generated signals of up to 20 times that of BCF-12-based detectors. The study presents solutions to unwanted luminescence properties of ruby-based ISDs for high-dose-rate brachytherapy. An optic filter should be sandwiched between the ruby crystal and the fiber-optic cable to suppress the photoluminescence. Furthermore, we recommend avoiding ruby crystals that exhibit significant time-dependent luminescence.

Using Fiber Optic Distributed Acoustic Sensing to Measure Hydromechanics in a Crystalline Rock Aquifer

NASA Astrophysics Data System (ADS)

Ciervo, C.; Becker, M.; Cole, M. C.; Coleman, T.; Mondanos, M.

2016-12-01

Measuring hydromechanical behavior in fractured rock is important for hydraulic fracturing and stimulation in petroleum reservoirs, predicting thermal effects in geothermal fields, and monitoring geologic carbon sequestration injection. We present a new method for measuring geomechanical response to fluid pressure in fractures that employs fiber optic Distributed Acoustic Sensing (DAS). DAS was designed to measure acoustic and seismic signals, often in petroleum wells. DAS seismic monitoring has been proposed as a particularly useful tool for performing seismic testing for carbon sequestration and geothermal projects because fiber optic cable is able to withstand high temperatures and pressures. DAS measures seismic vibration in the Hz to kHz frequency range by measuring strain rate in the fiber optic cable. We adapted this technology to measure rock strain in response to periodic hydraulic pulses in the mHz frequency range. A field experiment was conducted in a low-permeability fractured crystalline bedrock to test the ability of DAS to measure hydromechanical response to periodic pumping and injection. The fiber optic cable was coupled to the borehole wall using a flexible liner designed with an air coupled transducer to measure fluid pressure. Both strain and pressure were measured across a known fracture zone hydraulically connected to the pumping/injection well 30 m away. Periodic strain with amplitudes as small as 50 nm were measured in response to head amplitudes of 2 mm. Clean strain signals were detected at all tested periods of hydraulic oscillation ranging from 2 to 18 minutes. A non-linear relationship was found between opening and closing of the fracture (as measured by cable strain) and fluid pressure in the fracture. The response was also sensitive to the fiber optic cable design. This field test suggests potential for measuring hydraulic connectivity and hydromechanical behavior in fractured formations through cementing fiber optic cable in wellbores outside of well casings.

Subcarrier Wave Quantum Key Distribution in Telecommunication Network with Bitrate 800 kbit/s

NASA Astrophysics Data System (ADS)

Gleim, A. V.; Nazarov, Yu. V.; Egorov, V. I.; Smirnov, S. V.; Bannik, O. I.; Chistyakov, V. V.; Kynev, S. M.; Anisimov, A. A.; Kozlov, S. A.; Vasiliev, V. N.

2015-09-01

In the course of work on creating the first quantum communication network in Russia we demonstrated quantum key distribution in metropolitan optical network infrastructure. A single-pass subcarrier wave quantum cryptography scheme was used in the experiments. BB84 protocol with strong reference was chosen for performing key distribution. The registered sifted key rate in an optical cable with 1.5 dB loss was 800 Kbit/s. Signal visibility exceeded 98%, and quantum bit error rate value was 1%. The achieved result is a record for this type of systems.

Single-mode glass waveguide technology for optical interchip communication on board level

NASA Astrophysics Data System (ADS)

Brusberg, Lars; Neitz, Marcel; Schröder, Henning

2012-01-01

The large bandwidth demand in long-distance telecom networks lead to single-mode fiber interconnects as result of low dispersion, low loss and dense wavelength multiplexing possibilities. In contrast, multi-mode interconnects are suitable for much shorter lengths up to 300 meters and are promising for optical links between racks and on board level. Active optical cables based on multi-mode fiber links are at the market and research in multi-mode waveguide integration on board level is still going on. Compared to multi-mode, a single-mode waveguide has much more integration potential because of core diameters of around 20% of a multi-mode waveguide by a much larger bandwidth. But light coupling in single-mode waveguides is much more challenging because of lower coupling tolerances. Together with the silicon photonics technology, a single-mode waveguide technology on board-level will be the straight forward development goal for chip-to-chip optical interconnects integration. Such a hybrid packaging platform providing 3D optical single-mode links bridges the gap between novel photonic integrated circuits and the glass fiber based long-distance telecom networks. Following we introduce our 3D photonic packaging approach based on thin glass substrates with planar integrated optical single-mode waveguides for fiber-to-chip and chip-to-chip interconnects. This novel packaging approach merges micro-system packaging and glass integrated optics. It consists of a thin glass substrate with planar integrated singlemode waveguide circuits, optical mirrors and lenses providing an integration platform for photonic IC assembly and optical fiber interconnect. Thin glass is commercially available in panel and wafer formats and characterizes excellent optical and high-frequency properties. That makes it perfect for microsystem packaging. The paper presents recent results in single-mode waveguide technology on wafer level and waveguide characterization. Furthermore the integration in a hybrid packaging process and design issues are discussed.

Investigation into longitudinal placement of fiber-optic cable in Interstate right-of-way in Louisiana : technical assistance report.

DOT National Transportation Integrated Search

1995-11-01

Fiber-optic cable is recognized as one of the most efficient and reliable mediums of telecommunication available today. The last decade has witnessed an enormous growth in this form of telecommunication. However, one of its major disadvantages is tha...

Disposable telemetry cable deployment system

DOEpatents

Holcomb, David Joseph

2000-01-01

A disposable telemetry cable deployment system for facilitating information retrieval while drilling a well includes a cable spool adapted for insertion into a drill string and an unarmored fiber optic cable spooled onto the spool cable and having a downhole end and a stinger end. Connected to the cable spool is a rigid stinger which extends through a kelly of the drilling apparatus. A data transmission device for transmitting data to a data acquisition system is disposed either within or on the upper end of the rigid stinger.

Phase 9 Fiber Optic Cable Microbending and Temperature Cycling Tests

NASA Technical Reports Server (NTRS)

Abushagur, Mustafa A.G.; Huang, Po T.; Hand, Larry

1996-01-01

Optical fibers represent the back bone of the current communications networks. Their performance in the field lacks long term testing data because of the continuous evolution of the manufacturing of fibers and cables. An optical fiber cable that is installed in NASA's KSC has experienced a dramatic increase in attenuation after three years of use from 0.7 dB/km to 7 dB/km in some fibers. A thorough study is presented to assess the causes of such an attenuation increase. Material and chemical decomposition testing showed that there are no changes in the composition of the fiber which might have caused the increase in attenuation. Microbending and heat cycling tests were performed on the cable and individual fibers. It was found that the increase in attenuation is due to microbending caused by excessive stress exerted on the fibers. This was the result of manufacturing and installation irregularities.

Light Water Reactor Sustainability Program: Evaluation of Localized Cable Test Methods for Nuclear Power Plant Cable Aging Management Programs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glass, Samuel W.; Fifield, Leonard S.; Hartman, Trenton S.

This Pacific Northwest National Laboratory (PNNL) milestone report describes progress to date on the investigation of nondestructive test (NDE) methods focusing particularly on local measurements that provide key indicators of cable aging and damage. The work includes a review of relevant literature as well as hands-on experimental verification of inspection capabilities. As NPPs consider applying for second, or subsequent, license renewal (SLR) to extend their operating period from 60 years to 80 years, it important to understand how the materials installed in plant systems and components will age during that time and develop aging management programs (AMPs) to assure continuedmore » safe operation under normal and design basis events (DBE). Normal component and system tests typically confirm the cables can perform their normal operational function. The focus of the cable test program is directed toward the more demanding challenge of assuring the cable function under accident or DBE. Most utilities already have a program associated with their first life extension from 40 to 60 years. Regrettably, there is neither a clear guideline nor a single NDE that can assure cable function and integrity for all cables. Thankfully, however, practical implementation of a broad range of tests allows utilities to develop a practical program that assures cable function to a high degree. The industry has adopted 50% elongation at break (EAB) relative to the un-aged cable condition as the acceptability standard. All tests are benchmarked against the cable EAB test. EAB is a destructive test so the test programs must apply an array of other NDE tests to assure or infer the overall set of cable’s system integrity. These cable NDE programs vary in rigor and methodology. As the industry gains experience with the efficacy of these programs, it is expected that implementation practice will converge to a more common approach. This report addresses the range of local NDE cable tests that are or could be practically implemented in a field test situation. These tests include: visual, infrared thermography, interdigital capacitance, indenter, relaxation time indenter, dynamic mechanical analyzer, infrared/near-infrared spectrometry, ultrasound, and distributed fiber optic temperature measurement.« less

Miniaturized tool for optogenetics based on an LED and an optical fiber interfaced by a silicon housing.

PubMed

Schwaerzle, M; Elmlinger, P; Paul, O; Ruther, P

2014-01-01

This paper reports on the design, simulation, fabrication and characterization of a tool for optogenetic experiments based on a light emitting diode (LED). A minimized silicon (Si) interface houses the LED and aligns it to an optical fiber. With a Si housing size of 550×500×380 μm(3) and an electrical interconnection of the LED by a highly flexible polyimide (PI) ribbon cable is the system very variable. PI cables and Si housings are fabricated using established microsystem technologies. A 270×220×50 μm(3) bare LED chip is flip-chip-bonded onto the PI cable. The Si housing is adhesively attached to the PI cable, thereby hosting the LED in a recess. An opposite recess guides the optical fiber with a diameter of 125 μm. An aperture in-between restricts the emitted LED light to the fiber core. The optical fiber is adhesively fixed into the Si housing recess. An optical output intensity at the fiber end facet of 1.71 mW/mm(2) was achieved at a duty cycle of 10 % and a driving current of 30 mA.

The temperature and tension characteristics of the FBGs embedded in the polythene sheath of an optical cable

NASA Astrophysics Data System (ADS)

Chen, Guanghui; Zhao, Ming; Sha, Jianbo; Zhang, Jun; Wu, Bingyan; Lin, Chen; Zhang, Mingliang; Gao, Kan

2015-10-01

The five of FBG were embedded in the PE sheath of a tether optical cable, which has about 18mm diameter and 7000mm length. The temperature and tension characteristics of the FBGs embedded in the polythene (PE) sheath had been demonstrated quantitatively. The Bragg wavelength of the embedded FBG shift linearly with the change of pulling force loaded on the tether optical cable and its tension sensitivity is about 3.75 pm/kg. The results of temperature experiment suggest the embedded FBG have been sensitized by PE material, so that its temperature sensitivity increase from 9.37pm/°C to about 12.51pm/°C.

The Design of Passive Optical Networking+Ethernet over Coaxial Cable Access Networking and Video-on-Demand Services Carrying

NASA Astrophysics Data System (ADS)

Ji, Wei

2013-07-01

Video on demand is a very attractive service used for entertainment, education, and other purposes. The design of passive optical networking+Ethernet over coaxial cable accessing and a home gateway system is proposed. The network integrates the passive optical networking and Ethernet over coaxial cable to provide high dedicated bandwidth for the metropolitan video-on-demand services. Using digital video broadcasting, IP television protocol, unicasting, and broadcasting mechanisms maximizes the system throughput. The home gateway finishes radio frequency signal receiving and provides three kinds of interfaces for high-definition video, voice, and data, which achieves triple-play and wire/wireless access synchronously.

Heterogeneous 3D optrode with variable spatial resolution for optogenetic stimulation and electrophysiological recording.

PubMed

Ayub, Suleman; Barz, Falk; Paul, Oliver; Ruther, Patrick

2016-08-01

We report on the concept, development, and geometrical, optical as well as electrical characterization of the first three-dimensional (3D) optrode. This new device allows to optically interact with neuronal cells and simultaneously record their response with a high spatial resolution. Our design is based on a single-shank optical stimulation component and a multi-shank recording probe stacked together in a delicate assembly process. The electrical connection of both components is ensured by using flexible polyimide (PI) ribbon cables. The highly accurate relative positioning and precise alignment of the optical and electrical components in 3D with an optical output power at 460 nm well above 5 mW/mm2 and an all-electrical interface makes this device a promising tool for optogenetic experiments in neuroscientific research.

Feasibility of using cone penetrometer truck (CPT) to install time domain reflectometry (TDR) and fiber optic slope failure detectors in pavement structures.

DOT National Transportation Integrated Search

2011-02-01

A new method of cable installation using a heavy-duty Cone Penetration Test : (CPT) truck was developed and practiced successfully in this study. The coaxial and fiber : optic cables were pushed along with the cone rods by the hydraulic system integr...

Head-mounted LED for optogenetic experiments of freely-behaving animal

NASA Astrophysics Data System (ADS)

Kwon, Ki Yong; Gnade, Andrew G.; Rush, Alexander D.; Patten, Craig D.

2016-03-01

Recent developments in optogenetics have demonstrated the ability to target specific types of neurons with sub-millisecond temporal precision via direct optical stimulation of genetically modified neurons in the brain. In most applications, the beam of a laser is coupled to an optical fiber, which guides and delivers the optical power to the region of interest. Light emitting diodes (LEDs) are an alternative light source for optogenetics and they provide many advantages over a laser based system including cost, size, illumination stability, and fast modulation. Their compact size and low power consumption make LEDs suitable light sources for a wireless optogenetic stimulation system. However, the coupling efficiency of an LED's output light into an optical fiber is lower than a laser due to its noncollimated output light. In typical chronic optogenetic experiment, the output of the light source is transmitted to the brain through a patch cable and a fiber stub implant, and this configuration requires two fiber-to-fiber couplings. Attenuation within the patch cable is potential source of optical power loss. In this study, we report and characterize a recently developed light delivery method for freely-behaving animal experiments. We have developed a head-mounted light source that maximizes the coupling efficiency of an LED light source by eliminating the need for a fiber optic cable. This miniaturized LED is designed to couple directly to the fiber stub implant. Depending on the desired optical power output, the head-mounted LED can be controlled by either a tethered (high power) or battery-powered wireless (moderate power) controller. In the tethered system, the LED is controlled through 40 gauge micro coaxial cable which is thinner, more flexible, and more durable than a fiber optic cable. The battery-powered wireless system uses either infrared or radio frequency transmission to achieve real-time control. Optical, electrical, mechanical, and thermal characteristics of the head-mounted LED were evaluated.

Application of Optical Diagnosis to Aged Low-Voltage Cable Insulation in Nuclear Plants

NASA Astrophysics Data System (ADS)

Katagiri, Junichi; Takezawa, Yoshitaka; Shouji, Hiroshi

We have developed a novel non-destructive optical diagnosis technique for low-voltage cable insulations used in nuclear power plants. The key features of this diagnosis are the use of two wavelengths to measure the change in reflective absorbance (ΔAR), the use of polarized light to measure crystallinity and the use of element volatilizing to measure fluorescence. Chemical kinetics is used to predict the lifetimes of the cable insulations. When cable insulations darken and harden by time degradation, the ΔAR and depolarization parameters increase. This means that the cross-linking density in the cable insulations increases due to deterioration reactions. When the cross-linking density of insulation increases, its elasticity, corresponding to the material's life, increases. Similarly, as the crystallinity increases due to the change in the high-order structure of the insulating resin caused by irradiation, its elongation property decreases. The elongation property of insulation is one of the most important parameters that can be used to evaluate material lifetimes, because it relates to elasticity. The ΔAR correlated with the elongation property, and the correlation coefficient of an accelerated experiment using model pieces was over 0.9. Thus, we concluded that this optical diagnosis should be applied to evaluate the degradation of cable insulations used in nuclear power plants.

Demonstration of a Low Cost, High-Speed Fiber Optic Transceiver

DTIC Science & Technology

2002-09-01

200 610 (2) 800 600 (3) Diameter of cable(s) (mm) 0.125 3 7 (4) 100×10 (5) Weight (5 m cable, kg) (6) 0.008 0.1 0.51 0.5 Reliability ( MTTF hrs...Based on 1E7 hour MTTF number from Honeywell preliminary data sheet (8) Based on 12 VCSELs, log-normal distribution, σ = 0.225 Technical...A009 on Form DD 1423-1 Optical Link for Radar Digital Processor Andrew Davidson, Terri L. Dooley, Grant R. Emmel, Robert A. Marsland, and

Airborne-Fiber Optics Manufacturing Technology, Aircraft Installation Processes.

DTIC Science & Technology

1980-08-19

but the impact is minor. With simpler equipment and techniques there may be a J’ 1 -, long- term savings potential. Overall costs and benefits of...4/72 1 * lh427 ,. . . ... .. - - . .. . 4.0 ASSEMBLY OF FIBER OPTIC CABLES AND HARNESSES 4.1 CABLE IDENTIFICATION (Marking) 4.1.1 Physically identify...FIBER OPTICS MANUFACTURING TECHNOLOGY Aircraft Installation Processes G Kosmos ~ ~ 19 August 1980 I 2 Final Report: May 1978 - June 1980 . 1 Prepared for

GEOS-20 m cable boom mechanism

NASA Technical Reports Server (NTRS)

Schmidt, B. K.; Suttner, K.

1977-01-01

The GEOS cable boom mechanism allows the controlled deployment of a 20 m long cable in a centrifugal force field. In launch configuration the flat cable is reeled on a 240 mm diameter drum. The electrical connection between the rotating drum and the stationary housing is accomplished via a flexlead positioned inside the drum. Active motion control of this drum is achieved by a self locking worm gear, driven by a stepper motor. The deployment length of the cable is monitored by an optical length indicator, sensing black bars engraved on the cable surface.

Ultrafast FADC multiplexer

NASA Astrophysics Data System (ADS)

Mirzoyan, R.; Cortina, J.; Lorenz, E.; Martinez, M.; Ostankov, A.; Paneque, D.

2002-10-01

Ultrafast Flash amplitude-to-digital converters (FADCs) are still very expensive. Here we propose a multiplexing scheme allowing one in common trigger mode to read out multiple signal sources by using a single FADC channel. Usual coaxial cables can be used in the multiplexer as analog signal delay elements. The limited bandwidth of the coaxial cable, depending on its type and length will set an upper limit to the number of multiplexed channels. Better bandwidth and the correspondingly higher number of multiplexed channels one can obtain when using the technique of transmission of analog signals via optical fibers. Low-cost vertical cavity surface emitting laser (VCSEL) diodes can be used as converters of fast electrical signals into near infrared light. Multiplexing can be an economically priced solution when one needs ultrafast digitization of hundreds of fast signal channels.

75 FR 47583 - Application to Rescind Presidential Permit; Joint Application for Presidential Permit; British...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-06

... facilities authorized by Presidential Permit No. PP-22, as amended, include seven single conductor 132 kilovolt (kV) submarine cables and three single conductor 260 kV DC submarine cables. These cables do not...

Electro-Optic Fabrics for the Warrior of the 21st Century - Phase II

DTIC Science & Technology

2010-01-01

46 28. Effect of 1000 cycles of hex- abrasion testing on Fire Wire cable .................................... 46 UNCLASSIFIED vi 29. Close...49 32. Effect of 2000 cycles of hex- abrasion testing on Fire Wire cable .................................... 49 33. Effect of 4000 cycles of...hex- abrasion testing on Fire Wire cable .................................... 50 34. Effect of 2000 cycles of hex- abrasion testing on USB v2 cable

Laser Safety Method For Duplex Open Loop Parallel Optical Link

DOEpatents

Baumgartner, Steven John; Hedin, Daniel Scott; Paschal, Matthew James

2003-12-02

A method and apparatus are provided to ensure that laser optical power does not exceed a "safe" level in an open loop parallel optical link in the event that a fiber optic ribbon cable is broken or otherwise severed. A duplex parallel optical link includes a transmitter and receiver pair and a fiber optic ribbon that includes a designated number of channels that cannot be split. The duplex transceiver includes a corresponding transmitter and receiver that are physically attached to each other and cannot be detached therefrom, so as to ensure safe, laser optical power in the event that the fiber optic ribbon cable is broken or severed. Safe optical power is ensured by redundant current and voltage safety checks.

30 CFR 7.403 - Application requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Electric Cables, Signaling Cables, and Cable Splice Kits § 7.403 Application requirements. (a) Electric cables and signaling cables. A single... product: (1) Product information: (i) Cable type (for example, G or G-GC). (ii) Construction (for example...

30 CFR 7.403 - Application requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Electric Cables, Signaling Cables, and Cable Splice Kits § 7.403 Application requirements. (a) Electric cables and signaling cables. A single... product: (1) Product information: (i) Cable type (for example, G or G-GC). (ii) Construction (for example...

30 CFR 7.403 - Application requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Electric Cables, Signaling Cables, and Cable Splice Kits § 7.403 Application requirements. (a) Electric cables and signaling cables. A single... product: (1) Product information: (i) Cable type (for example, G or G-GC). (ii) Construction (for example...

7 CFR 1755.3 - Field trials.

Code of Federal Regulations, 2014 CFR

2014-01-01

...) Trunk carriers; (iii) Subscriber carrier; (iv) Point-to-point radio (Microwave); (v) Coaxial cable system electronics; (vi) Fiber optic cable system electronics; (vii) Multiplex equipment; (viii) Mobile...

7 CFR 1755.3 - Field trials.

Code of Federal Regulations, 2013 CFR

2013-01-01

...) Trunk carriers; (iii) Subscriber carrier; (iv) Point-to-point radio (Microwave); (v) Coaxial cable system electronics; (vi) Fiber optic cable system electronics; (vii) Multiplex equipment; (viii) Mobile...

7 CFR 1755.3 - Field trials.

Code of Federal Regulations, 2012 CFR

2012-01-01

...) Trunk carriers; (iii) Subscriber carrier; (iv) Point-to-point radio (Microwave); (v) Coaxial cable system electronics; (vi) Fiber optic cable system electronics; (vii) Multiplex equipment; (viii) Mobile...

Permanent installation of fibre-optic DTS cables in boreholes for temperature monitoring

NASA Astrophysics Data System (ADS)

Henninges, J.; Schrötter, J.; Erbas, K.; Böde, S.; Huenges, E.

2003-04-01

Temperature measurements have become an important tool for the monitoring of dynamic processes in the subsurface both in academia and industry. An innovative experimental design for the monitoring of spatial and temporal variations of temperature along boreholes was developed and successfully applied under extreme arctic conditions during a field experiment, which was carried out within the framework of the Mallik 2002 Production Research Well Program*. Three 40 m spaced, 1200 m deep wells were equipped with permanent fibre-optic sensor cables and the variation of temperature was measured deploying the Distributed Temperature Sensing (DTS) technology. The used DTS system enables the simultaneous online registration of temperature profiles along the three boreholes with a maximum spatial resolution of 0.25 m and a minimum sampling interval of 7 sec. After an individual calibration of the fibre-optic sensor cables a resolution of 0.3 °C of the measured temperature data could be achieved. A special feature of the experiment design is the installation of the sensor cables outside the borehole casing. The fibre-optic cables were attached to the outer side of the casing at every connector within intervals of approx. 12 m with cable clamps. The clamps enable a defined positioning of the cable around the perimeter of the casing and are protecting the cable from mechanical damage during installation. After completion the sensor cables are located in the cement annulus between casing and borehole wall. As an example of the performance of the described temperature logging technology data from the reaming of a 300 m thick cement plug inside the borehole is displayed, offering a unique opportunity to explore thermal processes in the near vicinity of a borehole during drilling. The temperature changes image the progress of the drill bit as well as changes in the mud circulation. Furthermore, local effects can be observed that relate to local thermal properties and technical features of the cable installation. (*) The program participants include 8 partners; The Geological Survey of Canada (GSC), The Japan National Oil Corporation (JNOC), GeoForschungsZentrum Potsdam (GFZ), United States Geological Survey (USGS), United States Department of the Energy (USDOE), India Ministry of Petroleum and Natural Gas (MOPNG)/Gas Authority of India (GAIL) and the Chevron-BP-Burlington joint venture group.

Preliminary photovoltaic arc-fault prognostic tests using sacrificial fiber optic cabling.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Jay Dean; Blemel, Kenneth D.; Peter, Francis

2013-02-01

Through the New Mexico Small Business Assistance Program, Sandia National Laboratories worked with Sentient Business Systems, Inc. to develop and test a novel photovoltaic (PV) arc-fault detection system. The system operates by pairing translucent polymeric fiber optic sensors with electrical circuitry so that any external abrasion to the system or internal heating causes the fiber optic connection to fail or detectably degrade. A periodic pulse of light is sent through the optical path using a transmitter-receiver pair. If the receiver does not detect the pulse, an alarm is sounded and the PV system can be de-energized. This technology has themore » unique ability to prognostically determine impending failures to the electrical system in two ways: (a) the optical connection is severed prior to physical abrasion or cutting of PV DC electrical conductors, and (b) the polymeric fiber optic cable melts via Joule heating before an arc-fault is established through corrosion. Three arc-faults were created in different configurations found in PV systems with the integrated fiber optic system to determine the feasibility of the technology. In each case, the fiber optic cable was broken and the system annunciated the fault.« less

The GEOS-20 m Cable Boom Mechanism

NASA Technical Reports Server (NTRS)

Schmidt, G. K.; Suttner, K.

1977-01-01

The GEOS Cable Boom Mechanism which allows the controlled deployment of a 20 m long cable in a centrifugal force field is described. In launch configuration the flat cable is reeled on a 240 mm diameter drum. The electrical connection between the rotating drum and the stationary housing is accomplished via a flexlead positioned inside the drum. Active motion control of this drum is achieved by a self locking worm gear, driven by a stepper motor. The deployment length of the cable is monitored by an optical length indicator, sensing black bars engraved on the cable surface.

Influences of Excess Oscillation of Voltage Pulse and Discharge Mode on NO Removal Using Barrier-Type Plasma Reactor

NASA Astrophysics Data System (ADS)

Kadowaki, Kazunori; Suzuki, Yoshiaki; Ihori, Haruo; Kitani, Isamu

This paper presents experimental results of NO removal from a simulated exhausted-gas using a barrier type reactor with screw electrodes subjected to polarity-reversed voltage pulses. The polarity-reversed pulse was produced by direct grounding of a charged coaxial cable because a traveling wave voltage was negatively reflected at the grounding end with a change in its polarity and then it propagated to the plasma reactor at the opposite end. Influence of cable length on NO removal was studied for two kinds of cable connection, single-connected cable and parallel-connected cables. NO removal ratio for a 50m-long cable was lower than that for much shorter cables in both single and parallel connections when the applied voltage became high. Energy efficiency for NO removal also increased with decreasing the cable length. This was because excess discharges during the voltage oscillation caused by the large stored energy in the long cable resulted in reproduction of NO molecules. Energy efficiency was further improved by changing the discharge mode from dielectric barrier discharge (DBD) to surface discharge (SD). Energy efficiency was up to 110g/kWh with 55% NO removal ratio and 34g/kWh with 100% NO removal ratio by using a single 10m-long cable in SD mode.

Fibre Optic Connections And Method For Using Same

DOEpatents

Chan, Benson; Cohen, Mitchell S.; Fortier, Paul F.; Freitag, Ladd W.; Hall, Richard R.; Johnson, Glen W.; Lin, How Tzu; Sherman, John H.

2004-03-30

A package is described that couples a twelve channel wide fiber optic cable to a twelve channel Vertical Cavity Surface Emitting Laser (VCSEL) transmitter and a multiple channel Perpendicularly Aligned Integrated Die (PAID) receiver. The package allows for reduction in the height of the assembly package by vertically orienting certain dies parallel to the fiber optic cable and horizontally orienting certain other dies. The assembly allows the vertically oriented optoelectronic dies to be perpendicularly attached to the horizontally oriented laminate via a flexible circuit.

Medical devices utilizing optical fibers for simultaneous power, communications and control

DOEpatents

Fitch, Joseph P.; Matthews, Dennis L.; Hagans, Karla G.; Lee, Abraham P.; Krulevitch, Peter; Benett, William J.; Clough, Robert E.; DaSilva, Luiz B.; Celliers, Peter M.

2003-06-10

A medical device is constructed in the basic form of a catheter having a distal end for insertion into and manipulation within a body and a proximal end providing for a user to control the manipulation of the distal end within the body. A fiberoptic cable is disposed within the catheter and having a distal end proximate to the distal end of the catheter and a proximal end for external coupling of laser light energy. A laser-light-to-mechanical-power converter is connected to receive light from the distal end of the fiber optic cable and may include a photo-voltaic cell and an electromechanical motor or a heat-sensitive photo-thermal material. An electronic sensor is connected to receive electrical power from said distal end of the fiberoptic cable and is connected to provide signal information about a particular physical environment and communicated externally through the fiberoptic cable to the proximal end thereof. A mechanical sensor is attached to the distal end of the fiberoptic cable and connected to provide light signal information about a particular physical environment and communicated externally through the fiberoptic cable.

Development and qualification of a fiber optic cable for Martian environments

NASA Astrophysics Data System (ADS)

Lindensmith, C. A.; Roberts, W. T.; Meacham, M.; Ott, M. N.; LaRocca, F.; Thomes, W. J.

2017-11-01

ChemCam is an instrument suite on the Mars Science Laboratory (MSL) mission that will launch to Mars in 2011. MSL is a rover-type lander that is capable of exploring large territories over the mission lifetime and includes a number of instruments for analysing rocks and soil. ChemCam includes a laser induced breakdown spectroscopy (LIBS) [1] instrument that samples the surface chemistry of target objects within about 10 m of the rover without having to physically move to the target to obtain emission spectra in the 240 nm to 800 nm range. The ChemCam laser and sensing telescope are mounted on the rover Remote Sensing Mast (RSM) and have 360 degrees of azimuthal range, and 180 degrees of vertical range, allowing sampling of any object within range and line-of-sight of the mast top. This capability can be used to select targets for further analysis by other MSL instruments. The LIBS portion of ChemCam is split between the top of the RSM and inside the rover body. The laser and the telescope are located atop the mast and rotate to select and observe targets. The three spectrometers (UV, VIS, and NIR) are located inside the rover body, along with a demultiplexer (demux) that splits the signal into the three bands. The signal from the telescope is transmitted to the demux by the fiber optic cable that is the subject of this paper. The fiber optic cable (FOC) is a single 5.7-m long, broadband, mult-mode fiber that connects the telescope and demux and is exposed to the full martian environment in some places and subjected to significant temperature gradients as it runs from interior areas to exterior areas.

ATM over hybrid fiber-coaxial cable networks: practical issues in deploying residential ATM services

NASA Astrophysics Data System (ADS)

Laubach, Mark

1996-11-01

Residential broadband access network technology based on asynchronous transfer modem (ATM) will soon reach commercial availability. The capabilities provided by ATM access network promise integrated services bandwidth available in excess of those provided by traditional twisted pair copper wire public telephone networks. ATM to the side of the home placed need quality of service capability closest to the subscriber allowing immediate support for Internet services and traditional voice telephony. Other services such as desktop video teleconferencing and enhanced server-based application support can be added as part of future evolution of the network. Additionally, advanced subscriber home networks can be supported easily. This paper presents an updated summary of the standardization efforts for the ATM over HFC definition work currently taking place in the ATM forum's residential broadband working group and the standards progress in the IEEE 802.14 cable TV media access control and physical protocol working group. This update is fundamental for establishing the foundation for delivering ATM-based integrated services via a cable TV network. An economic model for deploying multi-tiered services is presenting showing that a single-tier service is insufficient for a viable cable operator business. Finally, the use of an ATM based system lends itself well to various deployment scenarios of synchronous optical networks (SONET).

High-Resolution Monitoring of Soil Water Dynamics in a Vegetated Hillslope by Active Distributed Temperature Sensing

NASA Astrophysics Data System (ADS)

Ciocca, F.; Krause, S.; Blaen, P.; Hannah, D. M.; Chalari, A.; Mondanos, M.; Abesser, C.

2016-12-01

Water and thermal conditions in the shallow vadose zone can be very complex and dynamic across a range of spatiotemporal scales. The efficient analysis of such dynamics requires technologies capable of precise and high-resolution monitoring of soil temperature and moisture across multiple scales. Optical fibre distributed temperature sensors (DTS) allows for precise temperature measurements at high spatio-temporal resolution, over several kilometres of optical fibre cable. In addition to passive temperature monitoring, hybrid optical cables with embedded metal conductors can be electrically heated and allow for distributed heat pulses. Such Active-DTS technique involves the analysis of temperatures during both heating and cooling phases of an optical fibre cable buried in the soil in order to provide distributed soil moisture estimates. In summer 2015, three loops of a 500m hybrid-optical cable have been deployed at 10cm, 25cm and 40cm depths along a hillslope with juvenile forest. Active-DTS surveys have been conducted with the aim to: (i) monitor the post-installation soil settling around the cable; (ii) analyse different heating strategies (intensity, duration) of the cable; (iii) establish a method for inferring soil moisture from Active-DTS results and validate with independent soil moisture readings from point probes; (iv) monitor the soil moisture response to short forcing events such as storms and artificial irrigation. Results from the surveys will be presented, and first assumptions on how the obtained soil water dynamics can be associated to specific triggers such as precipitation, evapotranspiration, soil inclination, will be discussed. This research is part of the British National Environmental Research Council (NERC) funded Distributed intelligent Heat Pulse System (DiHPS) project and is realised in the context of the Free Air Carbon Enrichment (FACE) experiment, in collaboration with the Birmingham Institute of Forest Research (BIFoR).

Fiber optic multiplex optical transmission system

NASA Technical Reports Server (NTRS)

Bell, C. H. (Inventor)

1977-01-01

A multiplex optical transmission system which minimizes external interference while simultaneously receiving and transmitting video, digital data, and audio signals is described. Signals are received into subgroup mixers for blocking into respective frequency ranges. The outputs of these mixers are in turn fed to a master mixer which produces a composite electrical signal. An optical transmitter connected to the master mixer converts the composite signal into an optical signal and transmits it over a fiber optic cable to an optical receiver which receives the signal and converts it back to a composite electrical signal. A de-multiplexer is coupled to the output of the receiver for separating the composite signal back into composite video, digital data, and audio signals. A programmable optic patch board is interposed in the fiber optic cables for selectively connecting the optical signals to various receivers and transmitters.

Development of a single-phase 30 m HTS power cable

NASA Astrophysics Data System (ADS)

Cho, Jeonwook; Bae, Joon-Han; Kim, Hae-Jong; Sim, Ki-Deok; Kim, Seokho; Jang, Hyun-Man; Lee, Chang-Young; Kim, Dong-Wook

2006-05-01

HTS power transmission cables appear to be the replacement and retrofitting of underground cables in urban areas and HTS power transmission cable offers a number of technical and economic merits compared to the normal conductor cable system. A 30 m long, single-phase 22.9 kV class HTS power transmission cable system has been developed by Korea Electrotechnology Research Institute (KERI), LS Cable Ltd., and Korea Institute of Machinery and Materials (KIMM), which is one of the 21st century frontier project in Korea since 2001. The HTS power cable has been developed, cooled down and tested to obtain realistic thermal and electrical data on HTS power cable system. The evaluation results clarified such good performance of HTS cable that DC critical current of the HTS cable was 3.6 kA and AC loss was 0.98 W/m at 1260 Arms and shield current was 1000 Arms. These results proved the basic properties for 22.9 kV HTS power cable. As a next step, we have been developing a 30 m, three-phase 22.9 kV, 50 MV A HTS power cable system and long term evaluation is in progress now.

Biomechanical performance of different cable and wire cerclage configurations.

PubMed

Lenz, Mark; Perren, Stephan Marcel; Richards, Robert Geoff; Mückley, Thomas; Hofmann, Gunther Olaf; Gueorguiev, Boyko; Windolf, Markus

2013-01-01

Cerclage technology is regaining interest due to the increasing number of periprosthetic fractures. Different wiring techniques have been formerly proposed and have hibernated over years. Hereby, they are compared to current cerclage technology. Seven groups (n = 6) of different cable cerclage (Ø1.7 mm, crimp closure) configurations (one single cerclage looped once around the shells, one single cerclage looped twice, two cerclages each looped once) and solid wire cerclages (Ø1.5 mm, twist closure) (same configurations as cable cerclages, and two braided wires, twisted around each other looped once) fixed two cortical half shells of human femoral shaft mounted on a testing jig. Sinusoidal cyclic loading with constantly increasing force (0.1 N/cycle) was applied starting at 50 N peak load. Cerclage pretension (P), load leading to onset of plastic deformation (D) and load at total failure (T) were identified. Statistical differences between the groups were detected by univariate ANOVA. Double looped cables (P442N ± 129; D1334N ± 319; T2734N ± 330) performed significantly better (p < 0.05) than single looped cables (P292N ± 56; D646N ± 108; T1622N ± 171) and were comparable to two single cables (P392N ± 154; D1191N ± 334; T2675N ± 361). Double looped wires (P335N ± 49; D752N ± 119; T1359N ± 80) were significantly better (p < 0.05) than single looped wires (P181N ± 16; D343N ± 33; T606N ± 109) and performed similarly to single looped cables. Braided wires (P119N ± 26; D225N ± 55; T919N ± 197) exhibited early loss of pretension and plastic deformation. Double looped cerclages provided a better fixation stability compared to a single looped cerclage. Double looped wires were comparable to a single looped cable. The use of braided wires could not be recommended mechanically.

Bed conduction impact on fiber optic distributed temperature sensing water temperature measurements

NASA Astrophysics Data System (ADS)

O'Donnell Meininger, T.; Selker, J. S.

2015-02-01

Error in distributed temperature sensing (DTS) water temperature measurements may be introduced by contact of the fiber optic cable sensor with bed materials (e.g., seafloor, lakebed, streambed). Heat conduction from the bed materials can affect cable temperature and the resulting DTS measurements. In the Middle Fork John Day River, apparent water temperature measurements were influenced by cable sensor contact with aquatic vegetation and fine sediment bed materials. Affected cable segments measured a diurnal temperature range reduced by 10% and lagged by 20-40 min relative to that of ambient stream temperature. The diurnal temperature range deeper within the vegetation-sediment bed material was reduced 70% and lagged 240 min relative to ambient stream temperature. These site-specific results illustrate the potential magnitude of bed-conduction impacts with buried DTS measurements. Researchers who deploy DTS for water temperature monitoring should understand the importance of the environment into which the cable is placed on the range and phase of temperature measurements.

Technical Note: Bed conduction impact on fiber optic DTS water temperature measurements

NASA Astrophysics Data System (ADS)

O'Donnell Meininger, T.; Selker, J. S.

2014-07-01

Error in Distributed Temperature Sensor (DTS) water temperature measurements may be introduced by contact of the fiber optic cable sensor with bed materials (e.g., seafloor, lakebed, stream bed). Heat conduction from the bed materials can affect cable temperature and the resulting DTS measurements. In the Middle Fork John Day River, apparent water temperature measurements were influenced by cable sensor contact with aquatic vegetation and fine sediment bed materials. Affected cable segments measured a diurnal temperature range reduced by 10% and lagged by 20-40 min relative to that of ambient stream temperature. The diurnal temperature range deeper within the vegetation-sediment bed material was reduced 70% and lagged 240 min relative to ambient stream temperature. These site-specific results illustrate the potential magnitude of bed-conduction impacts with buried DTS measurements. Researchers who deploy DTS for water temperature monitoring should understand the importance of the environment into which the cable is placed on the range and phase of temperature measurements.

Ergonomic design considerations for an optical data link between a warfighter's head and body-worn technologies

NASA Astrophysics Data System (ADS)

Trew, Noel; Linn, Aaron; Nelson, Zac; Burnett, Greg; Sedillo, Mike

2012-06-01

Today, warfighters are burdened by a web of cables linking technologies that span the head and torso regions of the body. These cables help to provide interoperability between helmet-worn peripherals such as head mounted displays (HMDs), cameras, and communication equipment with chest-worn computers and radios. Although promoting enhanced capabilities, this cabling also poses snag hazards and makes it difficult for the warfighter to extricate himself from his kit when necessary. A newly developed wireless personal area network (WPAN), one that uses optical transceivers, may prove to be an acceptable alternative to traditional cabling. Researchers at the Air Force Research Laboratory's 711th Human Performance Wing are exploring how best to mount the WPAN transceivers to the body in order to facilitate unimpeded data transfer while also maintaining the operator's natural range of motion. This report describes the two-step research process used to identify the performance limitations and usability of a body-worn optical wireless system. Firstly, researchers characterized the field of view for the current generation of optical WPAN transceivers. Then, this field of view was compared with anthropometric data describing the range of motion of the cervical vertebrae to see if the data link would be lost at the extremes of an operator's head movement. Finally, this report includes an additional discussion of other possible military applications for an optical WPAN.

7 CFR 1755.903 - Fiber optic service entrance cables.

Code of Federal Regulations, 2010 CFR

2010-01-01

... group or core designs must consist of 12 fibers or less. (3) When threads or tapes are used as core...: Cable designs must meet the requirements of Part 7, Testing and Test Methods, of ICEA S-110-717... testing. (1) The tests described in this section are intended for acceptance of cable designs and major...

7 CFR 1755.903 - Fiber optic service entrance cables.

Code of Federal Regulations, 2012 CFR

2012-01-01

... group or core designs must consist of 12 fibers or less. (3) When threads or tapes are used as core...: Cable designs must meet the requirements of Part 7, Testing and Test Methods, of ICEA S-110-717... testing. (1) The tests described in this section are intended for acceptance of cable designs and major...

7 CFR 1755.903 - Fiber optic service entrance cables.

Code of Federal Regulations, 2014 CFR

2014-01-01

... group or core designs must consist of 12 fibers or less. (3) When threads or tapes are used as core...: Cable designs must meet the requirements of Part 7, Testing and Test Methods, of ICEA S-110-717... testing. (1) The tests described in this section are intended for acceptance of cable designs and major...

7 CFR 1755.903 - Fiber optic service entrance cables.

Code of Federal Regulations, 2011 CFR

2011-01-01

... group or core designs must consist of 12 fibers or less. (3) When threads or tapes are used as core...: Cable designs must meet the requirements of Part 7, Testing and Test Methods, of ICEA S-110-717... testing. (1) The tests described in this section are intended for acceptance of cable designs and major...

7 CFR 1755.903 - Fiber optic service entrance cables.

Code of Federal Regulations, 2013 CFR

2013-01-01

... group or core designs must consist of 12 fibers or less. (3) When threads or tapes are used as core...: Cable designs must meet the requirements of Part 7, Testing and Test Methods, of ICEA S-110-717... testing. (1) The tests described in this section are intended for acceptance of cable designs and major...

Effects of ascending and descending climbers on space elevator cable dynamics

NASA Astrophysics Data System (ADS)

Ishikawa, Yoji; Otsuka, Kiyotoshi; Yamagiwa, Yoshiki; Doi, Hinata

2018-04-01

Based on a mass-point model, the cable dynamics of a space elevator during a climber's travel motion are examined. The cable response during a single operation of one ascending or descending climber is analyzed first, and then, based on the results, the cable dynamics for simultaneous operation of an ascending and a descending climber are evaluated. For the single operation, bending is significant when the climber is traveling near the Earth's surface. The cable also inclines with periodic oscillation as a result of a Coriolis force corresponding to the climber velocity. However, simultaneous operation of ascending and descending climbers can suppress the inclination of the cable by almost a factor of ten. In simultaneous operation, compared to single operation, a descending climber has a smaller amplitude of libration angle and less cable bending, while an ascending climber has a smaller amplitude when the climber is traveling at a higher altitude with climber velocities of 200 km/h and 400 km/h. The phase of the oscillation of the overall cable is found to be close to that of the descending climber. Cable bending is suppressed for any examined climber velocity, but the dependency of this suppression of displacement on climber velocity is not found. In summary, simultaneous operation can surely suppress the inclination of the cable via the cancellation of Coriolis forces by the two climbers.

Controlling the Optical and Magnetic Properties of Nanostructured Cuprous Oxide Synthesized from Waste Electric Cables

NASA Astrophysics Data System (ADS)

Abdelbasir, S. M.; El-Sheikh, S. M.; Rashad, M. M.; Rayan, D. A.

2018-03-01

Cuprous oxide Cu2O nanopowders were purposefully synthesised from waste electric cables (WECs) via a simple precipitation route at room temperature using lactose as a reducing agent. In this regard, dimethyl sulfoxide (DMSO) was first applied as an organic solvent for the dissolution of the cable insulating materials. Several parameters were investigated during dissolution of WECs such as dissolution temperature, time and solid/liquid ratio to determine the dissolution percentage of the insulating materials in DMSO. The morphology and the optical properties of the formed Cu2O particles were investigated using X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy and UV-visible-near IR spectrophotometer. XRD data confirmed the presence of single crystalline phase of Cu2O nanoparticles. FE-SEM and TEM images revealed spherical, cubic and octahedral shapes with the various particle sizes ranged from 16 to 57 nm depending on the synthesis conditions. A possible mechanism explaining the Cu2O nanostructures formation was proposed. The band gap energies of the Cu2O nanostructures were estimated and the values were located between 1.5 and 2.08 eV. Photoluminescence spectroscopy analysis clearly showed a noticeably blue-shifted emission for the synthesized samples compared to spectrum of the bulk. Eventually, magnetic properties of the synthesized nanoparticles have been measured by vibrating sample magnetometer and the attained results implied that the synthesized particles are weakly ferromagnetic in nature at normal temperature.

Deck and Cable Dynamic Testing of a Single-span Bridge Using Radar Interferometry and Videometry Measurements

NASA Astrophysics Data System (ADS)

Piniotis, George; Gikas, Vassilis; Mpimis, Thanassis; Perakis, Harris

2016-03-01

This paper presents the dynamic testing of a roadway, single-span, cable-stayed bridge for a sequence of static load and ambient vibration monitoring scenarios. Deck movements were captured along both sideways of the bridge using a Digital Image Correlation (DIC) and a Ground-based Microwave Interfererometer (GBMI) system. Cable vibrations were measured at a single point location on each of the six cables using the GBMI technique. Dynamic testing involves three types of analyses; firstly, vibration analysis and modal parameter estimation (i. e., natural frequencies and modal shapes) of the deck using the combined DIC and GBMI measurements. Secondly, dynamic testing of the cables is performed through vibration analysis and experimental computation of their tension forces. Thirdly, the mechanism of cable-deck dynamic interaction is studied through their Power Spectra Density (PSD) and the Short Time Fourier Transform (STFT) analyses. Thereby, the global (deck and cable) and local (either deck or cable) bridge modes are identified, serving a concrete benchmark of the current state of the bridge for studying the evolution of its structural performance in the future. The level of synergy and complementarity between the GBMI and DIC techniques for bridge monitoring is also examined and assessed.

Research and Development on Ultra-Lightweight Low-Loss Optical Fiber Communication Cable.

DTIC Science & Technology

FIBER OPTICS TRANSMISSION LINES, LIGHTWEIGHT), GLASS , FIBERS , ORGANIC COATINGS, POLYURETHANE RESINS, SOLUTIONS(GENERAL), POWDERS, ELECTROSTATICS...EXTRUSION, RUGGEDIZED EQUIPMENT, BROADBAND, OPTICAL COMMUNICATIONS, TACTICAL COMMUNICATIONS, FIBER OPTICS, LOSSES.

Ultrasonic imaging using optoelectronic transmitters.

PubMed

Emery, C D; Casey, H C; Smith, S W

1998-04-01

Conventional ultrasound scanners utilize electronic transmitters and receivers at the scanner with a separate coaxial cable connected to each transducer element in the handle. The number of transducer elements determines the size and weight of the transducer cable assembly that connects the imaging array to the scanner. 2-D arrays that allow new imaging modalities to be introduced significantly increase the channel count making the transducer cable assembly more difficult to handle. Therefore, reducing the size and increasing the flexibility of the transducer cable assembly is a concern. Fiber optics can be used to transmit signals optically and has distinct advantages over standard coaxial cable to increase flexibility and decrease the weight of the transducer cable for larger channel numbers. The use of fiber optics to connect the array and the scanner entails the use of optoelectronics such as detectors and laser diodes to send and receive signals. In transmit, optoelectronics would have to be designed to produce high-voltage wide-bandwidth pulses across the transducer element. In this paper, we describe a 48 channel ultrasound system having 16 optoelectronic transmitters and 32 conventional electronic receivers. We investigated both silicon avalanche photodiodes (APD's) and GaAs lateral photoconductive semiconductor switches (PCSS's) for producing the transmit pulses. A Siemens SI-1200 scanner and a 2.25 MHz linear array were used to compare the optoelectronic system to a conventional electronic transmit system. Transmit signal results and images in tissue mimicking of cysts and tumors are provided for comparison.

Microminiaturized minimally invasive intravascular micro-mechanical systems powered and controlled via fiber-optic cable

DOEpatents

Fitch, J.P.; Hagans, K.; Clough, R.; Matthews, D.L.; Lee, A.P.; Krulevitch, P.A.; Benett, W.J.; Silva, L. Da; Celliers, P.M.

1998-03-03

A micro-mechanical system for medical procedures is constructed in the basic form of a catheter having a distal end for insertion into and manipulation within a body and a near end providing for a user to control the manipulation of the distal end within the body. A fiber-optic cable is disposed within the catheter and having a distal end proximate to the distal end of the catheter and a near end for external coupling of laser light energy. A microgripper is attached to the distal end of the catheter and providing for the gripping or releasing of an object within the body. A laser-light-to-mechanical-power converter is connected to receive laser light from the distal end of the fiber-optic cable and connected to mechanically actuate the microgripper. 22 figs.

Instrument for measuring dispersional distortions in optical fibers and cables

NASA Astrophysics Data System (ADS)

Alishev, Y. V.; Maryenko, A. A.; Smirnov, Y. V.; Uryadov, V. N.; Sinkevich, V. I.

1985-03-01

An instrument was developed and built for measuring the dispersional distortions in optical fibers and cables on the basis of pulse widening. The instrument consists of a laser as a light source, a master oscillator, an optical transmitter, an optical shunt with mode mixer, an optical receiver, a fiber length measuring device, a smoothly adjustable delay line, and a stroboscopic oscillograph. The optical transmitter contains a semiconductor laser with GaAs-GaAlAs diheterostructure and modulator with pulse generating avalanche-breakdown transistors. The optical receiver contains a germanium photodiode with internal amplification and photoreceiver amplifier with microwave bipolar germanium transistors. Matching of the instrument to the tested fiber line is done by passing radiation into the latter from an auxiliary small He-Ne laser through a directional coupler.

Solar radiative heating of fiber-optic cables used to monitor temperatures in water

NASA Astrophysics Data System (ADS)

Neilson, Bethany T.; Hatch, Christine E.; Ban, Heng; Tyler, Scott W.

2010-08-01

In recent years, applications of distributed temperature sensing (DTS) have increased in number and diversity. Because fiber-optic cables used for DTS are typically sheathed in dark UV-resistant materials, the question arises as to how shortwave solar radiation penetrating a water column influences the accuracy of absolute DTS-derived temperatures in aquatic applications. To quantify these effects, we completed a modeling effort that accounts for the effects of radiation and convection on a submersed cable to predict when solar heating may be important. Results indicate that for cables installed at shallow depths in clear, low-velocity water bodies, measurable heating of the cable is likely during peak solar radiation. However, at higher velocities, increased turbidity and/or greater depths, the effects of solar heating are immeasurable. A field study illustrated the effects of solar radiation by installing two types of fiber-optic cable at multiple water depths (from 0.05 to 0.8 m) in the center and along the sidewall of a trapezoidal canal. Thermistors were installed at similar depths and shielded from solar radiation to record absolute water temperatures. During peak radiation, thermistor data showed small temperature differences (˜0.003°C-0.04°C) between depths suggesting minor thermal stratification in the canal center. DTS data from cables at these same depths show differences of 0.01°C-0.17°C. The DTS differences cannot be explained by stratification alone and are likely evidence of additional heating from solar radiation. Sidewall thermistor strings also recorded stratification. However, corresponding DTS data suggested that bed conduction overwhelmed the effects of solar radiation.

Locating illicit connections in storm water sewers using fiber-optic distributed temperature sensing.

PubMed

Hoes, O A C; Schilperoort, R P S; Luxemburg, W M J; Clemens, F H L R; van de Giesen, N C

2009-12-01

A newly developed technique using distributed temperature sensing (DTS) has been developed to find illicit household sewage connections to storm water systems in the Netherlands. DTS allows for the accurate measurement of temperature along a fiber-optic cable, with high spatial (2m) and temporal (30s) resolution. We inserted a fiber-optic cable of 1300m in two storm water drains. At certain locations, significant temperature differences with an intermittent character were measured, indicating inflow of water that was not storm water. In all cases, we found that foul water from households or companies entered the storm water system through an illicit sewage connection. The method of using temperature differences for illicit connection detection in storm water networks is discussed. The technique of using fiber-optic cables for distributed temperature sensing is explained in detail. The DTS method is a reliable, inexpensive and practically feasible method to detect illicit connections to storm water systems, which does not require access to private property.

STS-43 MS Adamson checks OCTW experiment on OV-104's aft flight deck

NASA Image and Video Library

1991-08-11

STS043-04-038 (2-11 Aug 1991) --- Astronaut James C. Adamson, STS-43 mission specialist, checks on an experiment on Atlantis? flight deck. Part of the experiment, Optical Communications Through the Shuttle Window (OCTW), can be seen mounted in upper right. The OCTW system consists of two modules, one inside the orbiter crew cabin (as pictured here) and one in the payload bay. The crew compartment version houses an optoelectronic transmitter/receiver pair for video and digital subsystems, test circuitry and interface circuitry. The payload bay module serves as a repeater station. During operation a signal is transmitted through the shuttle window to a bundle of optical fiber cables mounted in the payload bay near an aft window. The cables carry optical signals from the crew compartment equipment to the OCTW payload bay module. The signals are returned via optical fiber cable to the aft flight deck window, retransmitted through the window, and received by the crew compartment equipment.

Cable delay compensator for microwave signal distribution over optical fibers

NASA Astrophysics Data System (ADS)

Primas, Lori E.

1990-12-01

The basic principles of microwave fiber-optic systems are outlined with emphasis on fiber-optic cable delay compensators (CDC). Degradation of frequency and phase stability is considered, and it is pointed out that the long-term stability of a fiber-optic link is degraded by group delay variations due to temperature fluctuations in the optical fiber and low-frequency noise characteristics of the laser. A CDC employing a voltage-controlled oscillator to correct for phase variations in the optical fiber is presented, and the static as well as dynamic closed-loop analyses of the fiber-optic CDC are discussed. A constructed narrow-band fiber-optic CDC is shown to reduce phase variations caused by temperature fluctuations by a factor of 400. A wide-band CDC utilizing a temperature-controlled coil of fiber to compensate for phase delay is also proposed.

High temperature superconductors as a technological discontinuity in the power cable industry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beales, T.P.; McCormack, J.S.

1994-12-31

The advent of superconductivity above 77 K represents to the power cable industry a technological discontinuity analogous to that seen in the copper telecommunications industry by the arrival of optical fibres. This phenomenon is discussed along with technical criteria and performance targets needed for high temperature superconducting wire to have an economic impact in transmission cables.

High temperature superconductors as a technological discontinuity in the power cable industry

NASA Technical Reports Server (NTRS)

Beales, T. P.; Mccormack, J. S.

1995-01-01

The advent of superconductivity above 77 K represents to the power cable industry a technological discontinuity analogous to that seen in the copper telecommunications industry by the arrival of optical fibers. This phenomenon is discussed along with technical criteria and performance targets needed for high temperature superconducting wire to have an economic impact in transmission cables.

Turbidimeter Design and Analysis: A Review on Optical Fiber Sensors for the Measurement of Water Turbidity

PubMed Central

Omar, Ahmad Fairuz Bin; MatJafri, Mohd Zubir Bin

2009-01-01

Turbidimeters operate based on the optical phenomena that occur when incident light through water body is scattered by the existence of foreign particles which are suspended within it. This review paper elaborates on the standards and factors that may influence the measurement of turbidity. The discussion also focuses on the optical fiber sensor technologies that have been applied within the lab and field environment and have been implemented in the measurement of water turbidity and concentration of particles. This paper also discusses and compares results from three different turbidimeter designs that use various optical components. Mohd Zubir and Bashah and Daraigan have introduced a design which has simple configurations. Omar and MatJafri, on the other hand, have established a new turbidimeter design that makes use of optical fiber cable as the light transferring medium. The application of fiber optic cable to the turbidimeter will present a flexible measurement technique, allowing measurements to be made online. Scattered light measurement through optical fiber cable requires a highly sensitive detector to interpret the scattered light signal. This has made the optical fiber system have higher sensitivity in measuring turbidity compared to the other two simple turbidimeters presented in this paper. Fiber optic sensors provide the potential for increased sensitivity over large concentration ranges. However, many challenges must be examined to develop sensors that can collect reliable turbidity measurements in situ. PMID:22408507

Chemical-Sensing Cables Detect Potential Threats

NASA Technical Reports Server (NTRS)

2007-01-01

Intelligent Optical Systems Inc. (IOS) completed Phase I and II Small Business Innovation Research (SBIR) contracts with NASA's Langley Research Center to develop moisture- and pH-sensitive sensors to detect corrosion or pre-corrosive conditions, warning of potentially dangerous conditions before significant structural damage occurs. This new type of sensor uses a specially manufactured optical fiber whose entire length is chemically sensitive, changing color in response to contact with its target, and demonstrated to detect potentially corrosive moisture incursions to within 2 cm. After completing the work with NASA, the company received a Defense Advanced Research Projects Agency (DARPA) Phase III SBIR to develop the sensors further for detecting chemical warfare agents, for which they proved just as successful. The company then worked with the U.S. Department of Defense (DoD) to fine tune the sensors for detecting potential threats, such as toxic industrial compounds and nerve agents. In addition to the work with government agencies, Intelligent Optical Systems has sold the chemically sensitive fiber optic cables to major automotive and aerospace companies, who are finding a variety of uses for the devices. Marketed under the brand name Distributed Intrinsic Chemical Agent Sensing and Transmission (DICAST), these unique continuous-cable fiber optic chemical sensors can serve in a variety of applications: Corrosive-condition monitoring, aiding experimentation with nontraditional power sources, as an economical means of detecting chemical release in large facilities, as an inexpensive "alarm" systems to alert the user to a change in the chemical environment anywhere along the cable, or in distance-resolved optical time domain reflectometry systems to provide detailed profiles of chemical concentration versus length.

A miniature cable-driven robot for crawling on the heart.

PubMed

Patronik, N A; Zenati, M A; Riviere, C N

2005-01-01

This document describes the design and preliminary testing of a cable-driven robot for the purpose of traveling on the surface of the beating heart to administer therapy. This methodology obviates mechanical stabilization and lung deflation, which are typically required during minimally invasive cardiac surgery. Previous versions of the robot have been remotely actuated through push-pull wires, while visual feedback was provided by fiber optic transmission. Although these early models were able to perform locomotion in vivo on porcine hearts, the stiffness of the wire-driven transmission and fiber optic camera limited the mobility of the robots. The new prototype described in this document is actuated by two antagonistic cable pairs, and contains a color CCD camera located in the front section of the device. These modifications have resulted in superior mobility and visual feedback. The cable-driven prototype has successfully demonstrated prehension, locomotion, and tissue dye injection during in vitro testing with a poultry model.

A physical layer perspective on access network sharing

NASA Astrophysics Data System (ADS)

Pfeiffer, Thomas

2015-12-01

Unlike in copper or wireless networks, there is no sharing of resources in fiber access networks yet, other than bit stream access or cable sharing, in which the fibers of a cable are let to one or multiple operators. Sharing optical resources on a single fiber among multiple operators or different services has not yet been applied. While this would allow for a better exploitation of installed infrastructures, there are operational issues which still need to be resolved, before this sharing model can be implemented in networks. Operating multiple optical systems and services over a common fiber plant, autonomously and independently from each other, can result in mutual distortions on the physical layer. These distortions will degrade the performance of the involved systems, unless precautions are taken in the infrastructure hardware to eliminate or to reduce them to an acceptable level. Moreover, the infrastructure needs to be designed such as to support different system technologies and to ensure a guaranteed quality of the end-to-end connections. In this paper, suitable means are proposed to be introduced in fiber access infrastructures that will allow for shared utilization of the fibers while safeguarding the operational needs and business interests of the involved parties.

A direct modulated optical link for MRI RF receive coil interconnection.

PubMed

Yuan, Jing; Wei, Juan; Shen, G X

2007-11-01

Optical glass fiber is a promising alternative to traditional coaxial cables for MRI RF receive coil interconnection to avoid any crosstalk and electromagnetic interference between multiple channels. A direct modulated optical link is proposed for MRI coil interconnection in this paper. The link performances of power gain, frequency response and dynamic range are measured. Phantom and in vivo human head images have been demonstrated by the connection of this direct modulated optical link to a head coil on a 0.3T MRI scanner for the first time. Comparable image qualities to coaxial cable link verify the feasibility of using the optical link for imaging with minor modification on the existing scanners. This optical link could also be easily extended for multi-channel array interconnections at high field of 1.5 T.

AUV Commercialization - Who’s Leading the Pack?

DTIC Science & Technology

2000-09-01

the Theseus and ARCS, is designing a deep water commercial site survey AUV for Fugro GeoServices Inc. Called the Explorer, the vehicle will conduct...ISE has the ARCS and the Theseus vehicles and Perry Technologies has the MUST. These vehicles have each performed some dramatic operations including the...deployment of fiber optic cables. In the case of Theseus , the fiber optic cable was deployed under the ice pack. Mid-size vehicles include those from

JPRS Report, Science & Technology, China.

DTIC Science & Technology

1992-12-16

Optic Cable Ltd., with a gross investment of US$12.60 million; this firm will market the LXE bundle- tube lightweight fiber optic cable product...trap. There are four types of chemical generators commonly used to produce 02(’A): bubbler, atomizer, wet wall tube array and rotating disk. The...used in small COIL experiments. Figure 2 is a schematic diagram of the device. Chlorine gas passes through a bubbler (glass tube with many drilled

High-power fiber optic cable with integrated active sensors for live process monitoring

NASA Astrophysics Data System (ADS)

Blomster, Ola; Blomqvist, Mats; Bergstrand, Hans; Pålsson, Magnus

2012-03-01

In industrial applications using high-brilliance lasers at power levels up to and exceeding 20 kW and similarly direct diode lasers of 10 kW, there is an increasing demand to continuously monitor component status even in passive components such as fiber-optic cables. With fiber-optic cables designed according to the European Automotive Industry fiber standard interface there is room for integrating active sensors inside the connectors. In this paper we present the integrated active sensors in the new Optoskand QD fiber-optic cable designed to handle extreme levels of power losses, and how these sensors can be employed in industrial manufacturing. The sensors include photo diodes for detection of scattered light inside the fiber connector, absolute temperature of the fiber connector, difference in temperature of incoming and outgoing cooling water, and humidity measurement inside the fiber connector. All these sensors are connected to the fiber interlock system, where interlock break enable functions can be activated when measured signals are higher than threshold levels. It is a very fast interlock break system as the control of the signals is integrated in the electronics inside the fiber connector. Also, since all signals can be logged it is possible to evaluate what happened inside the connector before the interlock break instance. The communication to the fiber-optic connectors is via a CAN interface. Thus it is straightforward to develop the existing laser host control to also control the CAN-messages from the QD sensors.

Optical design of a color film recorder with PLZT modulators

NASA Astrophysics Data System (ADS)

Carson, John F.

1990-08-01

A continuous tone colour film recorder was constructed that exposes 8 x 10 inch ISO 100 daylight-balanced sheet film in ten minutes at a resolution of 1000 pixels/inch. A rotating drum is used for line scan and a leadscrew driven by a stepper motor for page scan. Film loading and unloading is automatic. Light from a stationary xenon arc lamp is split into red green and blue channel components and conducted to a translating optical system by multimode optical fiber cables. Each colour component is then modulated by a small-area PLZT light valve. An annular portion of the modulated light beam is reflected to a photodetector whose signal is used for closed-loop modulator control. The central transmitted portion of the modulated beam is combined with the other colour components into a single beam. This beam illuminates an aperture that is imaged onto the film. An overview of the mechanical electrical and optical concepts will be presented with emphasis on the optical design. 1.

Readout Strategy of an Electro-optical Coupled PET Detector for Time-of-Flight PET/MRI

PubMed Central

Bieniosek, M F; Olcott, P D; Levin, C S

2013-01-01

Combining PET with MRI in a single system provides clinicians with complementary molecular and anatomical information. However, existing integrated PET/MRI systems do not have time-of-flight PET capabilities. This work describes an MRI-compatible front-end electronic system with ToF capabilities. The approach employs a fast arrival-time pickoff comparator to digitize the timing information, and a laser diode to drive a 10m fiber-optic cable to optically transmit asynchronous timing information to a photodiode receiver readout system. The comparator and this electo-optical link show a combined 11.5ps fwhm jitter in response to a fast digital pulse. When configured with LYSO scintillation crystals and Hamamatsu MPPC silicon photo-multipliers the comparator and electro-optical link achieved a 511keV coincidence time resolution of 254.7ps +/− 8.0ps fwhm with 3×3×20mm crystals and 166.5 +/− 2.5ps fwhm with 3×3×5mm crystals. PMID:24061218

Statistical characteristics of excess fiber length in loose tubes of optical cable

NASA Astrophysics Data System (ADS)

Andreev, Vladimir A.; Gavryushin, Sergey A.; Popov, Boris V.; Popov, Victor B.; Vazhdaev, Michael A.

2017-04-01

This paper presents an analysis of the data measurements of excess fiber length in the loose tubes of optical cable during the post-process quality control of ready-made products. At determining estimates of numerical characteristics of excess fiber length method of results processing of direct multiple equally accurate measurements has been used. The results of experimental research of the excess length value at the manufacturing technology of loose tube remains constant.

Fiber Optic Cable Feedthrough and Sealing

NASA Technical Reports Server (NTRS)

Fan, Robert J.

1998-01-01

A novel fiberoptic hermetic bulkhead feedthrough has been developed which will offer cryogenic sealing at leak rates of 10(exp -11) cc/sec helium. This feedthrough was developed for NASA in response to needs for a hermetically sealed feedthrough which could withstand a range of temperatures from low cryogenic (-196 C), due to liquid fuels and oxidizers, to high temperatures (+200 C) encountered in the proximity of combustion gasses. The development effort will be reported from conceptual design of single and multi-channel feedthrough units with single interconnection interfaces to units with double-ended interconnection interfaces. Various combinations of fiber/buffers are reported with recommendations based on test results. A comprehensive series of environmental and mechanical tests were performed to evaluate the feedthroughs in adverse conditions. Test results are reported including insertion loss, salt spray, sinusoidal vibration, random vibration, mechanical shock, thermal shock and humidity. A second set of feedthrough units was exposed to 3 different types of radiation. Optical transmittance changes during the tests were monitored and leak rate testing was done after each test. State-of-the-art technology in optical fiber feedthroughs constructed with polycrystalline ceramic is presented.

Fiber optics spectrochemical emission sensors

DOEpatents

Griffin, Jeffrey W.; Olsen, Khris B.

1992-01-01

A method of in situ monitoring of a body of a fluid stored in a tank or groundwater or vadose zone gases in a well for the presence of selected chemical species uses a probe insertable into the well or tank via a cable and having electrical apparatus for exciting selected chemical species in the body of fluid. The probe can have a pair of electrodes for initiating a spark or a plasma cell for maintaining a plasma to excite the selected chemical species. The probe also has optical apparatus for receiving optical emissions emitted by the excited species and optically transmitting the emissions via the cable to an analysis location outside the well. The analysis includes detecting a selected wavelength in the emissions indicative of the presence of the selected chemical species. A plurality of probes can be suspended at an end of a respective cable, with the transmitting and analyzing steps for each probe being synchronized sequentially for one set of support equipment and instrumentation to monitor at multiple test points. The optical apparatus is arranged about the light guide axis so that the selected chemical species are excited the fluid in alignment with the light guide axis and optical emissions are received from the excited chemical species along such axis.

Fiber optics spectrochemical emission sensors

DOEpatents

Griffin, J.W.; Olsen, K.B.

1992-02-04

A method is described of in situ monitoring of a body of a fluid stored in a tank or groundwater or vadose zone gases in a well for the presence of selected chemical species. The method uses a probe insertable into the well or tank via a cable and having an electrical apparatus for exciting selected chemical species in the body of fluid. The probe can have a pair of electrodes for initiating a spark or a plasma cell for maintaining a plasma to excite the selected chemical species. The probe also has an optical apparatus for receiving optical emissions emitted by the excited species and optically transmitting the emissions via the cable to an analysis location outside the well. The analysis includes detecting a selected wavelength in the emissions indicative of the presence of the selected chemical species. A plurality of probes can be suspended at an end of a respective cable, with the transmitting and analyzing steps for each probe being synchronized sequentially for one set of support equipment and instrumentation to monitor at multiple test points. The optical apparatus is arranged about the light guide axis so that the selected chemical species are excited in the fluid in alignment with the light guide axis. Optical emissions are received from the excited chemical species along such axis. 18 figs.

Damping Estimation from Free Decay Responses of Cables with MR Dampers.

PubMed

Weber, Felix; Distl, Hans

2015-01-01

This paper discusses the damping measurements on cables with real-time controlled MR dampers that were performed on a laboratory scale single strand cable and on cables of the Sutong Bridge, China. The control approach aims at producing amplitude and frequency independent cable damping which is confirmed by the tests. The experimentally obtained cable damping in comparison to the theoretical value due to optimal linear viscous damping reveals that support conditions of the cable anchors, force tracking errors in the actual MR damper force, energy spillover to higher modes, and excitation and sensor cables hanging on the stay cable must be taken into consideration for the interpretation of the identified cable damping values.

Damping Estimation from Free Decay Responses of Cables with MR Dampers

PubMed Central

Weber, Felix; Distl, Hans

2015-01-01

This paper discusses the damping measurements on cables with real-time controlled MR dampers that were performed on a laboratory scale single strand cable and on cables of the Sutong Bridge, China. The control approach aims at producing amplitude and frequency independent cable damping which is confirmed by the tests. The experimentally obtained cable damping in comparison to the theoretical value due to optimal linear viscous damping reveals that support conditions of the cable anchors, force tracking errors in the actual MR damper force, energy spillover to higher modes, and excitation and sensor cables hanging on the stay cable must be taken into consideration for the interpretation of the identified cable damping values. PMID:26167537

Transients control in Raman fiber amplifiers

NASA Astrophysics Data System (ADS)

Freitas, Marcio; Givigi, Sidney N., Jr.; Klein, Jackson; Calmon, Luiz C.; de Almeida, Ailson R.

2004-11-01

Raman fiber amplifiers (RFA) are being used in optical transmission communication systems in the recent years due to their advantages in comparison to erbium-doped fiber amplifiers (EDFA). Recently the analysis of RFAs dynamic response and transients control has become important in order to predict the system response to add/drop of channels or cable cuts in optical systems, and avoid impairments caused by the power transients. Fast signal power transients in the surviving channels are caused by the cross-gain saturation effect in RFA and the slope of the gain saturation characteristics determines the steady-state surviving channel power excursion. We are presenting the modeling and analysis of power transients and its control using a pump control method for a single and multi-pump scheme.

Modular Seafloor and Water Column Systems for the Ocean Observatories Initiative Cabled Array

NASA Astrophysics Data System (ADS)

Delaney, J. R.; Manalang, D.; Harrington, M.; Tilley, J.; Dosher, J.; Cram, G.; Harkins, G.; McGuire, C.; Waite, P.; McRae, E.; McGinnis, T.; Kenney, M.; Siani, C.; Michel-Hart, N.; Denny, S.; Boget, E.; Kawka, O. E.; Daly, K. L.; Luther, D. S.; Kelley, D. S.; Milcic, M.

2016-02-01

Over the past decade, cabled ocean observatories have become an increasingly important way to collect continuous real-time data at remote subsea locations. This has led to the development of a class of subsea systems designed and built specifically to distribute power and bandwidth among sensing instrumentation on the seafloor and throughout the water column. Such systems are typically powered by shore-based infrastructure and involve networks of fiber optic and electrical cabling that provide real-time data access and control of remotely deployed instrumentation. Several subsea node types were developed and/or adapted for cabled use in order to complete the installation of the largest North American scientific cabled observatory in Oct, 2014. The Ocean Observatories Initiative (OOI) Cabled Array, funded by the US National Science Foundation, consists of a core infrastructure that includes 900 km of fiber optic/electrical cables, seven primary nodes, 18 seafloor junction boxes, three mooring-mounted winched profiling systems, and three wire-crawling profiler systems. In aggregate, the installed infrastructure has 200 dedicated scientific instrument ports (of which 120 are currently assigned), and is capable of further expansion. The installed system has a 25-year design life for reliable, sustained monitoring; and all nodes, profilers and instrument packages are ROV-serviceable. Now in it's second year of operation, the systems that comprise the Cabled Array are providing reliable, 24/7 real-time data collection from deployed instrumentation, and offer a modular and scalable class of subsea systems for ocean observing. This presentation will provide an overview of the observatory-class subsystems of the OOI Cabled Array, focusing on the junction boxes, moorings and profilers that power and communicate with deployed instrumentation.

Superconducting ac cable

NASA Astrophysics Data System (ADS)

Schmidt, F.

1980-11-01

The components of a superconducting 110 kV ac cable for power ratings or = 2000 MVA were developed. The cable design is of the semiflexible type, with a rigid cryogenic envelope containing a flexible hollow coaxial cable core. The cable core consists of spirally wound Nb-A1 composite wires electrically insulated by high pressure polyethylene tape wrappings. A 35 m long single phase test cable with full load terminals rated at 110 kV and 10 kA was constructed and successfully tested. The results obtained prove the technical feasibility and capability of this cable design.

On the measurement of intensity correlations from laboratory and astronomical sources with SPADs and SNSPDs

NASA Astrophysics Data System (ADS)

Schroeder, Edward; Mauskopf, Philip; Pilyavsky, Genady; Sinclair, Adrian; Smith, Nathan; Bryan, Sean; Mani, Hamdi; Morozov, Dmitry; Berggren, Karl; Zhu, Di; Smirnov, Konstantin; Vakhtomin, Yuriy

2016-08-01

We describe the performance of detector modules containing silicon single photon avalanche photodiodes (SPADs) and superconducting nanowire single photon detectors (SNSPDs) to be used for intensity interferometry. The SPADs are mounted in fiber-coupled and free-space coupled packages. The SNSPDs are mounted in a small liquid helium cryostat coupled to single mode fiber optic cables which pass through a hermetic feed-through. The detectors are read out with microwave amplifiers and FPGA-based coincidence electronics. We present progress on measurements of intensity correlations from incoherent sources including gas-discharge lamps and stars with these detectors. From the measured laboratory performance of the correlation system, we estimate the sensitivity to intensity correlations from stars using commercial telescopes and larger existing research telescopes.

Bimorphic polymeric photomechanical actuator

NASA Technical Reports Server (NTRS)

Sarkisov, Sergey S. (Inventor); Curley, Michael J. (Inventor); Adamovsky, Grigory (Inventor); Sarkisov, Jr., Sergey S. (Inventor); Fields, Aisha B. (Inventor)

2006-01-01

A bimorphic polymeric photomechanical actuator, in one embodiment using polyvinylidene fluoride (PVDF) as a photosensitive body, transmitting light over fiber optic cables, and controlling the shape and pulse duration of the light pulse to control movement of the actuator. Multiple light beams are utilized to generate different ranges of motion for the actuator from a single photomechanical body and alternative designs use multiple light beams and multiple photomechanical bodies to provide controlled movement. Actuator movement using one or more ranges of motion is utilized to control motion to position an actuating element in three dimensional space.

Fiber Optics Technology.

ERIC Educational Resources Information Center

Burns, William E.

1986-01-01

Discusses various applications of fiber optics technology: information systems, industrial robots, medicine, television, transportation, and training. Types of jobs that will be available with fiber optics training (such as electricians and telephone cable installers and splicers) are examined. (CT)

Copper link evaluations/solutions for fiber channel, SSA, SONET, ATM, and other services through 4 Gb/sec: basic information, test results, and evaluation

NASA Astrophysics Data System (ADS)

Leib, Michael J.

1995-10-01

Technitrol, the original designer of MIL-STD-1553 transformers, the original military 1Mb/s LAN, has advanced the state of the art one further notch, introducing a series of transceivers that allow high speed (through 1 Gb/s) data transmission over copper wire instead of fiber optic cable. One such device can be employed to implement the Fiber Channel Interface as defined by hte X3T11 ANSI Fibre Channel Committee using either mini coax, Type 1 shielded twisted pair, twinax or video cable. The technology now exists to upgrade data transmission rates on current physical media to speeds formerly only available with fiber optic cabling. Copper transceiver technology provides a cost effective alternative for dealing with demanding high speed applications such as high speed serial data transfer, high speed disk and tape storage transfer, imaging telemetry, radar, and other avionics applications. Eye diagrams will be presented to show that excellent data transmission at rates of 1 gigabit/sec with low jitter is capable over mini coax at distances to approximately 50 meters, shielded twisted pair and twinax cable to distances of 105 meters, and video cable to distances of 175 meters. Distances are further at lower data rates. As a member of the X3T11 ANSI Fiber Channel Committee, Technitrol has developed a Physical Media (copper wire) Dependant (PMD) transceiver not only compliant with the Fibre Channel Specifications but exceeding the specifications by a factor greater than four. Conceivably, this opens high speed interconnections for today's high data rate requirements to copper cabling systems. Fibre Optic problems need not be dealt with to obtain data transfers for high speed information transfers.

Buying Fiber-Optic Networks.

ERIC Educational Resources Information Center

Fickes, Michael

2003-01-01

Describes consortia formed by college and university administrators to buy, manage, and maintain their own fiber-optic networks with the goals of cutting costs of leasing fiber-optic cable and planning for the future. Growth capacity is the real advantage of owning fiber-optic systems. (SLD)

"Double-Cable" Conjugated Polymers with Linear Backbone toward High Quantum Efficiencies in Single-Component Polymer Solar Cells.

PubMed

Feng, Guitao; Li, Junyu; Colberts, Fallon J M; Li, Mengmeng; Zhang, Jianqi; Yang, Fan; Jin, Yingzhi; Zhang, Fengling; Janssen, René A J; Li, Cheng; Li, Weiwei

2017-12-27

A series of "double-cable" conjugated polymers were developed for application in efficient single-component polymer solar cells, in which high quantum efficiencies could be achieved due to the optimized nanophase separation between donor and acceptor parts. The new double-cable polymers contain electron-donating poly(benzodithiophene) (BDT) as linear conjugated backbone for hole transport and pendant electron-deficient perylene bisimide (PBI) units for electron transport, connected via a dodecyl linker. Sulfur and fluorine substituents were introduced to tune the energy levels and crystallinity of the conjugated polymers. The double-cable polymers adopt a "face-on" orientation in which the conjugated BDT backbone and the pendant PBI units have a preferential π-π stacking direction perpendicular to the substrate, favorable for interchain charge transport normal to the plane. The linear conjugated backbone acts as a scaffold for the crystallization of the PBI groups, to provide a double-cable nanophase separation of donor and acceptor phases. The optimized nanophase separation enables efficient exciton dissociation as well as charge transport as evidenced from the high-up to 80%-internal quantum efficiency for photon-to-electron conversion. In single-component organic solar cells, the double-cable polymers provide power conversion efficiency up to 4.18%. This is one of the highest performances in single-component organic solar cells. The nanophase-separated design can likely be used to achieve high-performance single-component organic solar cells.

Burning Characteristics and Flammability of PVC Cables in Groups

NASA Technical Reports Server (NTRS)

Mikado, T.; Akita, K.

1988-01-01

Because burning cables represent a danger of increasing secondary damage it is of utmost importance for disaster prevention to correctly evaluate the combustion characteristics of cable. However, in many cases cable is laid out in bundles complicating the combustion characteristics. A situation has developed where group cable characteristics are not completely understood. A new method is developed for testing the combustion of high polymer type cable and earlier reports gave comparative combustion measurement results. It was learned that there is considerable difference between the combustion characteristics of the grouped cables and those of single cables. This study is supplemental research concerning the special behavior of group PVC cables, throwing some light on their combustion characteristics.

7 CFR 1755.900 - Abbreviations and Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... to §§ 1755.901 and 1755.902: (a) Abbreviations. (1) ADSSAll dielectric self-supporting; (2...) Dielectric cable means a cable which has neither metallic members nor other electrically conductive materials... means any fiber made of dielectric material that guides light. (24) Optical point discontinuities means...

7 CFR 1755.900 - Abbreviations and Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... to §§ 1755.901 and 1755.902: (a) Abbreviations. (1) ADSSAll dielectric self-supporting; (2...) Dielectric cable means a cable which has neither metallic members nor other electrically conductive materials... means any fiber made of dielectric material that guides light. (24) Optical point discontinuities means...

Fiber-optic proximity sensor

NASA Technical Reports Server (NTRS)

Bejczy, A. K.; Hermann, W. A.; Primus, H. C.

1980-01-01

Proximity sensor for mechanical hand of remote manipulator incorporates fiber optics to conduct signals between light source and light detector. Fiber optics are not prone to noise from electromagnetic interference and radio-frequency interference as are sensors using long electrical cables.

Strength of cerclage fixation systems: a biomechanical study.

PubMed

Incavo, S J; Difazio, F; Wilder, D

1990-11-01

This study examined the load to failure ratio and stiffness of eight different cerclage techniques commonly used in the clinical management of fractures. For a single-loop cerclage, titanium cable was the strongest, while stainless steel wire secured with a commercial tightener was the weakest (P < 0.05). When a single-loop configuration is necessary (i.e. trochanteric attachment) a cable system is superior to cerclage wiring. A double-wrap of either cable or wire was considerably stronger than any single-wrap cerclage technique and stronger than two cerclage wires (P < 0.05). Copyright © 1990. Published by Elsevier Ltd.

Evaluation of Fibre Lifetime in Optical Ground Wire Transmission Lines

NASA Astrophysics Data System (ADS)

Grunvalds, R.; Ciekurs, A.; Porins, J.; Supe, A.

2017-06-01

In the research, measurements of polarisation mode dispersion of two OPGWs (optical ground wire transmission lines), in total four fibres, have been carried out, and the expected lifetime of the infrastructure has been assessed on the basis of these measurements. The cables under consideration were installed in 1995 and 2011, respectively. Measurements have shown that polarisation mode dispersion values for cable installed in 1995 are four times higher than that for cable installed in 2011, which could mainly be explained by technological differences in fibre production and lower fibre polarisation mode dispersion requirements in 1995 due to lack of high-speed (over 10 Gbit/s) optical transmission systems. The calculation methodology of non-refusal work and refusal probabilities, using the measured polarisation mode dispersion parameters, is proposed in the paper. Based on reliability calculations, the expected lifetime is then predicted, showing that all measured fibres most likely will be operational within minimum theoretical service life of 25 years accepted by the industry.

Cable Tester Box

NASA Technical Reports Server (NTRS)

Lee, Jason H.

2011-01-01

Cables are very important electrical devices that carry power and signals across multiple instruments. Any fault in a cable can easily result in a catastrophic outcome. Therefore, verifying that all cables are built to spec is a very important part of Electrical Integration Procedures. Currently, there are two methods used in lab for verifying cable connectivity. (1) Using a Break-Out Box and an ohmmeter this method is time-consuming but effective for custom cables and (2) Commercial Automated Cable Tester Boxes this method is fast, but to test custom cables often requires pre-programmed configuration files, and cables used on spacecraft are often uniquely designed for specific purposes. The idea is to develop a semi-automatic continuity tester that reduces human effort in cable testing, speeds up the electrical integration process, and ensures system safety. The JPL-Cable Tester Box is developed to check every single possible electrical connection in a cable in parallel. This system indicates connectivity through LED (light emitting diode) circuits. Users can choose to test any pin/shell (test node) with a single push of a button, and any other nodes that are shorted to the test node, even if they are in the same connector, will light up with the test node. The JPL-Cable Tester Boxes offers the following advantages: 1. Easy to use: The architecture is simple enough that it only takes 5 minutes for anyone to learn how operate the Cable Tester Box. No pre-programming and calibration are required, since this box only checks continuity. 2. Fast: The cable tester box checks all the possible electrical connections in parallel at a push of a button. If a cable normally takes half an hour to test, using the Cable Tester Box will improve the speed to as little as 60 seconds to complete. 3. Versatile: Multiple cable tester boxes can be used together. As long as all the boxes share the same electrical potential, any number of connectors can be tested together.

Packaging optical sensors for the real world

NASA Astrophysics Data System (ADS)

Kachmar, Wayne; Nardone, Kenneth C.

2007-09-01

Optical fiber based sensing has now moved from laboratory demonstrations to actual applications in the real world. This has necessitated an entirely new area of extrusion - the packaging (cabling) of optical fibers and sensor arrays to protect them from the intended environment and installation handling while not masking or attenuating the phenomenon that is being sensed. Although each application presents new and unique challenges, the goal is to create a packaging concept for fiber sensors. Fiber sensing applications can be narrowed down to the five items below: 1. Conventional cable packages 2. Assembled (typically by hand) discrete sensor packages 3. Package enhanced sensors (where the packaging improves the effect of the sensor) 4. Linear sensor installation packaging 5. Scalar packaging (where the cabling adds to the range of the sensor) The above applications can be accomplished in a number of ways, and methods are still being developed in this relatively new science. Some of the new technology methods being explored include: UV cured liquids; Voided space cores; Conventional cable extrusion & its determination of mechanical characteristics. This paper reviews the pluses and minuses of the above methods and how their combination ultimately determines how the fiber or sensor array is to be jacketed in order to meet the specific application requirements. This paper will also review non-standard material characteristics, strength members and their role in measuring strain and stress values along with the overall influence of packaging on optical fibers and sensor arrays.

Feasibility of Locating Leakages in Sewage Pressure Pipes Using the Distributed Temperature Sensing Technology.

PubMed

Apperl, Benjamin; Pressl, Alexander; Schulz, Karsten

2017-01-01

The cost effective maintenance of underwater pressure pipes for sewage disposal in Austria requires the detection and localization of leakages. Extrusion of wastewater in lakes can heavily influence the water and bathing quality of surrounding waters. The Distributed Temperature Sensing (DTS) technology is a widely used technique for oil and gas pipeline leakage detection. While in pipeline leakage detection, fiber optic cables are installed permanently at the outside or within the protective sheathing of the pipe; this paper aims at testing the feasibility of detecting leakages with temporary introduced fiber optic cable inside the pipe. The detection and localization were tested in a laboratory experiment. The intrusion of water from leakages into the pipe, producing a local temperature drop, served as indicator for leakages. Measurements were taken under varying measurement conditions, including the number of leakages as well as the positioning of the fiber optic cable. Experiments showed that leakages could be detected accurately with the proposed methodology, when measuring resolution, temperature gradient and measurement time were properly selected. Despite the successful application of DTS for leakage detection in this lab environment, challenges in real system applications may arise from temperature gradients within the pipe system over longer distances and the placement of the cable into the real pipe system.

Towards co-packaging of photonics and microelectronics in existing manufacturing facilities

NASA Astrophysics Data System (ADS)

Janta-Polczynski, Alexander; Cyr, Elaine; Bougie, Jerome; Drouin, Alain; Langlois, Richard; Childers, Darrell; Takenobu, Shotaro; Taira, Yoichi; Lichoulas, Ted W.; Kamlapurkar, Swetha; Engelmann, Sebastian; Fortier, Paul; Boyer, Nicolas; Barwicz, Tymon

2018-02-01

The impact of integrated photonics on optical interconnects is currently muted by challenges in photonic packaging and in the dense integration of photonic modules with microelectronic components on printed circuit boards. Single mode optics requires tight alignment tolerance for optical coupling and maintaining this alignment in a cost-efficient package can be challenging during thermal excursions arising from downstream microelectronic assembly processes. In addition, the form factor of typical fiber connectors is incompatible with the dense module integration expected on printed circuit boards. We have implemented novel approaches to interfacing photonic chips to standard optical fibers. These leverage standard high throughput microelectronic assembly tooling and self-alignment techniques resulting in photonic packaging that is scalable in manufacturing volume and in the number of optical IOs per chip. In addition, using dense optical fiber connectors with space-efficient latching of fiber patch cables results in compact module size and efficient board integration, bringing the optics closer to the logic chip to alleviate bandwidth bottlenecks. This packaging direction is also well suited for embedding optics in multi-chip modules, including both photonic and microelectronic chips. We discuss the challenges and rewards in this type of configuration such as thermal management and signal integrity.

Experimental validation of ultrasonic guided modes in electrical cables by optical interferometry.

PubMed

Mateo, Carlos; de Espinosa, Francisco Montero; Gómez-Ullate, Yago; Talavera, Juan A

2008-03-01

In this work, the dispersion curves of elastic waves propagating in electrical cables and in bare copper wires are obtained theoretically and validated experimentally. The theoretical model, based on Gazis equations formulated according to the global matrix methodology, is resolved numerically. Viscoelasticity and attenuation are modeled theoretically using the Kelvin-Voigt model. Experimental tests are carried out using interferometry. There is good agreement between the simulations and the experiments despite the peculiarities of electrical cables.

Demonstrated survivability of a high temperature optical fiber cable on a 1500 pound thrust rocket chamber

NASA Technical Reports Server (NTRS)

Sovie, Amy L.

1992-01-01

A demonstration of the ability of an existing optical fiber cable to survive the harsh environment of a rocket engine was performed at the NASA Lewis Research Center. The intent of this demonstration was to prove the feasibility of applying fiber optic technology to rocket engine instrumentation systems. Extreme thermal transient tests were achieved by wrapping a high temperature optical fiber, which was cablized for mechanical robustness, around the combustion chamber outside wall of a 1500 lb Hydrogen-Oxygen rocket engine. Additionally, the fiber was wrapped around coolant inlet pipes which were subject to near liquid hydrogen temperatures. Light from an LED was sent through the multimode fiber, and output power was monitored as a function of time while the engine was fired. The fiber showed no mechanical damage after 419 firings during which it was subject to transients from 30 K to 350 K, and total exposure time to near liquid hydrogen temperatures in excess of 990 seconds. These extreme temperatures did cause attenuation greater than 3 dB, but the signal was fully recovered at room temperature. This experiment demonstrates that commercially available optical fiber cables can survive the environment seen by a typical rocket engine instrumentation system, and disclose a temperature-dependent attenuation observed during exposure to near liquid hydrogen temperatures.

Frequency domain reflectometry NDE for aging cables in nuclear power plants

NASA Astrophysics Data System (ADS)

Glass, S. W.; Jones, A. M.; Fifield, L. S.; Hartman, T. S.

2017-02-01

Degradation of the cable jacket, electrical insulation, and other cable components of installed cables within nuclear power plants (NPPs) is known to occur as a function of age, temperature, radiation, and other environmental factors. Although system tests verify cable function under normal loads, demonstration of some cable's ability to perform under exceptional loads associated with design-basis events is essential to assuring plant integrity. The cable's ability to perform safely over the initial 40-year planned and licensed life has generally been demonstrated and there have been very few age-related cable failures. With greater than 1000 km of power, control, instrumentation, and other cables typically found in an NPP, replacing all the cables would be a severe cost burden. Justification for life extension to 60 and 80 years requires a cable aging management program that includes condition monitoring to justify cable performance under normal operation as well as accident conditions. A variety of tests are available to assess various aspects of electrical and mechanical cable performance, but none are suitable for all cable configurations nor does any single test confirm all features of interest. One particularly promising test that is beginning to be used more and more by utilities is frequency domain reflectometry (FDR). FDR is a nondestructive electrical inspection technique used to detect and localize faults in power and communication system conductors along the length of a cable from a single connection point. FDR detects discontinuities in the electrical impedance that arise due to cable splices or similar changes along the path of the conductor pair. In addition, FDR has the potential to provide sensitivity to insulation degradation by detecting small changes in impedance between the cable conductors being examined. The technique is also sensitive to cable bends, the particular lay of the cable in tray, proximity to other cable, and other factors that bear consideration when interpreting the test results. This paper examines various influences on the FDR approach and compares results of three different instruments to assess accelerated aging damage among several NPP representative cables.

Space Flight Cable Model Development

NASA Technical Reports Server (NTRS)

Spak, Kaitlin

2013-01-01

This work concentrates the modeling efforts presented in last year's VSGC conference paper, "Model Development for Cable-Harnessed Beams." The focus is narrowed to modeling of space-flight cables only, as a reliable damped cable model is not yet readily available and is necessary to continue modeling cable-harnessed space structures. New experimental data is presented, eliminating the low-frequency noise that plagued the first year's efforts. The distributed transfer function method is applied to a single section of space flight cable for Euler-Bernoulli and shear beams. The work presented here will be developed into a damped cable model that can be incorporated into an interconnected beam-cable system. The overall goal of this work is to accurately predict natural frequencies and modal damping ratios for cabled space structures.

Breaking wire detection and strain distribution of seven-wire steel cables with acoustic emission and optical fiber sensors.

DOT National Transportation Integrated Search

2013-09-01

Cable-stayed bridges have been increasingly used as river-crossing links in highway and railway transportation networks. In the event : of an abnormal situation, they can not only impact the local and national economy but also threaten the safety of ...

Design of an optical fiber cable link for lightning instrumentation. [wideband pulse recording system

NASA Technical Reports Server (NTRS)

Grove, C. H.; Phillips, R. L.; Wojtasinski, R. J.

1975-01-01

A lightning instrumentation system was designed to record current magnitudes of lightning strikes that hit a launch pad service structure at NASA's Kennedy Space Center. The instrumentation system consists of a lightning ground rod with a current sensor coil, an optical transmitter, an optical fiber cable link, a detector receiver, and a recording system. The transmitter is a wideband pulse transformer driving an IR LED emitter. The transmitter operates linearly as a transducer. A low loss fiber bundle provides isolation of the recorder system from the electromagnetic field of the lightning strike. The output of an optical detector receiver module is sampled and recorded in digital format. The significant factors considered in the design were dynamic range, linearity, mechanical configuration, electromagnetic isolation, and temperature compensation.

Compact multiwavelength transmitter module for multimode fiber optic ribbon cable

DOEpatents

Deri, Robert J.; Pocha, Michael D.; Larson, Michael C.; Garrett, Henry E.

2002-01-01

A compact multiwavelength transmitter module for multimode fiber optic ribbon cable, which couples light from an M.times.N array of emitters onto N fibers, where the M wavelength may be distributed across two or more vertical-cavity surface-emitting laser (VCSEL) chips, and combining emitters and multiplexer into a compact package that is compatible with placement on a printed circuit board. A key feature is bringing together two emitter arrays fabricated on different substrates--each array designed for a different wavelength--into close physical proximity. Another key feature is to compactly and efficiently combine the light from two or more clusters of optical emitters, each in a different wavelength band, into a fiber ribbon.

Optical Electronics. Electronics Module 9. Instructor's Guide.

ERIC Educational Resources Information Center

Franken, Bill

This module is the ninth of 10 modules in the competency-based electronics series. Introductory materials include a listing of competencies addressed in the module, a parts/equipment list, and a cross reference table of instructional materials. Five instructional units cover: fiber optic cable; optical coupler; lasers and masers; optical displays;…

Fiber optic (flight quality) sensors for advanced aircraft propulsion

NASA Technical Reports Server (NTRS)

Poppel, Gary L.

1994-01-01

Development of flight prototype, fiber-optic sensing system components for measuring nine sensed parameters (three temperatures, two speeds, three positions, and one flame) on an F404-400 aircraft engine is described. Details of each sensor's design, functionality, and environmental testing, and the electro-optics architecture for sensor signal conditioning are presented. Eight different optical sensing techniques were utilized. Design, assembly, and environmental testing of an engine-mounted, electro-optics chassis unit (EOU), providing MIL-C-1553 data output, are related. Interconnection cables and connectors between the EOU and the sensors are identified. Results of sensor/cable/circuitry integrated testing, and installation and ground testing of the sensor system on an engine in October 1993 and April 1994 are given, including comparisons with the engine control system's electrical sensors. Lessons learned about the design, fabrication, testing, and integration of the sensor system components are included.

Leaky coaxial cable signal transmission for remote facilities

NASA Astrophysics Data System (ADS)

Smith, S. F.; Crutcher, R. I.

To develop reliable communications methods to meet the rigorous requirements for nuclear hot cells and similar environments, including control of cranes, transporters, and advanced servomanipulators, the Consolidated Fuel Reprocessing Program (CFRP) at Oak Ridge National Laboratory (ORNL) has conducted extensive tests of numerous technologies to determine their applicability to remote operations. To alleviate the need for large bundles of cables that must accommodate crane/transporter motion relative to the boundaries of the cell, several transmission techniques are available, including slotted-line radio-frequency couplers, infrared beams, fiber-optic cables, free-space microwave, and inductively coupled leaky coaxial cable. This paper discusses the general characteristics, mode of operation, and proposed implementation of leaky coaxial cable technology in a waste-handling facility scheduled to be built in the near future at ORNL. In addition, specific system hardware based around the use of leaky coaxial cable is described in detail. Finally, data from a series of radiation exposure tests conducted by the CFRP on several samples of the basic leaky coaxial cable and associated connectors are presented.

An All-Dielectric Coaxial Waveguide.

PubMed

Ibanescu; Fink; Fan; Thomas; Joannopoulos

2000-07-21

An all-dielectric coaxial waveguide that can overcome problems of polarization rotation and pulse broadening in the transmission of optical light is presented here. It consists of a coaxial waveguiding region with a low index of refraction, bounded by two cylindrical, dielectric, multilayer, omnidirectional reflecting mirrors. The waveguide can be designed to support a single mode whose properties are very similar to the unique transverse electromagnetic mode of a traditional metallic coaxial cable. The new mode has radial symmetry and a point of zero dispersion. Moreover, because the light is not confined by total internal reflection, the waveguide can guide light around very sharp corners.

Custom electronic subsystems for the laboratory telerobotic manipulator

NASA Technical Reports Server (NTRS)

Glassell, R. L.; Butler, P. L.; Rowe, J. C.; Zimmermann, S. D.

1990-01-01

The National Aeronautics and Space Administration (NASA) Space Station Program presents new opportunities for the application of telerobotic and robotic systems. The Laboratory Telerobotic Manipulator (LTM) is a highly advanced 7 degrees-of-freedom (DOF) telerobotic/robotic manipulator. It was developed and built for the Automation Technology Branch at NASA's Langley Research Center (LaRC) for work in research and to demonstrate ground-based telerobotic manipulator system hardware and software systems for future NASA applications in the hazardous environment of space. The LTM manipulator uses an embedded wiring design with all electronics, motor power, and control and communication cables passing through the pitch-yaw differential joints. This design requires the number of cables passing through the pitch/yaw joint to be kept to a minimum. To eliminate the cables needed to carry each pitch-yaw joint's sensor data to the VME control computers, a custom-embedded electronics package for each manipulator joint was developed. The electronics package collects and sends the joint's sensor data to the VME control computers over a fiber optic cable. The electronics package consist of five individual subsystems: the VME Link Processor, the Joint Processor and the Joint Processor power supply in the joint module, the fiber optics communications system, and the electronics and motor power cabling.

7 CFR 1755.200 - RUS standard for splicing copper and fiber optic cables.

Code of Federal Regulations, 2010 CFR

2010-01-01

...) Color coded plastic tie wraps shall be placed loosely around each binder group of cables before splicing... conform to the same color designations as the binder ribbons. Twisted wire pigtails shall not be used to identify binder groups due to potential transmission degradation. (ii) The standard insulation color code...

SU-E-T-108: An Investigation of Cerenkov Light Production in the Exradin W1 Scintillator Under Various Measurement Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simiele, E; Culberson, W

2015-06-15

Purpose: To investigate the effects of depth, fiber-optic cable bends, and incident radiation angle on Cerenkov production in the Standard Imaging Exradin W1. Methods: Measurements were completed using a Varian Clinac 21EX linear accelerator with an Exradin W1 scintillator as well as a cable-only scintillator (no scintillation material) to isolate the Cerenkov signal. The effects of cable bend radius and location were investigated by bending the fiber-optic cable into a circle with radii ranging from 1.0 to 10.8 cm and positioning the center of the coil at distances ranging from 10.0 to 175.0 cm from the photodiode. The effects ofmore » depth and incident radiation angle were investigated by performing measurements in water at depths ranging from 1.0 cm to 25.0 cm and angles ranging from 0° to 80°. Eclipse treatment-planning software was utilized to ensure a consistent dose was delivered to the W1 regardless of depth or angle. Results: Measured signal in both channels of the cable-only scintillator decreased as the bend radius decreased and as the distance between the bend and photodiode increased. A fiber bend of 1.0 cm radius produced a 17.1% decrease in the green channel response in the cable-only scintillator. The effect of depth was less severe; a maximum increase of 6.6% in the green channel response was observed at a depth of 25.0 cm in the W1. In the angular dependence investigation, the signal in both channels of the W1 peaked at an angle of 40°; which is in agreement with the nominal Cerenkov emission angle of 45°. Conclusion: The green channel response in the W1 (mainly Cerenkov signal) varied with depth, fiber-optic cable bends, and incident radiation angle. Fully characterizing Cerenkov production is essential to ensure it is properly accounted for in scintillator measurements. Research funding and materials received by Standard Imaging, Inc. (Middleton WI)« less

Shedding Light on Fiber Optics.

ERIC Educational Resources Information Center

Bunch, Robert M.

1994-01-01

Explains the principles of fiber optics as a medium for light-wave communication. Current uses of fiber systems on college campuses include voice, video, and local area network applications. A group of seven school districts in Minnesota are linked via fiber-optic cables. Other uses are discussed. (MLF)

Application of active distribute temperature sensing and fiber optic as sensors to determinate the unsaturated hydraulic conductivity curve

NASA Astrophysics Data System (ADS)

Zubelzu, Sergio; Rodriguez-Sinobas, Leonor; Sobrino, Fernando

2017-04-01

The development of methodologies for the characterization of soil water content through the use of distribute temperature sensing and fiber optic cable has allowed for modelling with high temporal and spatial accuracy water movement in soils. One of the advantage of using fiber optic as a sensor, compared with the traditional point water probes, is the possibility to measure the variable continuously along the cable every 0.125 m (up to a cable length of 1500) and every second. Traditionally, applications based on fiber optic as a soil water sensor apply the active heated fiber optic technique AHFO to follow the evolution soil water content during and after irrigation events or for hydrologic characterization. However, this paper accomplishes an original experience by using AHFO as a sensor to characterize the soil hydraulic conductivity curve in subsaturated conditions. The non lineal nature between the hidraulic conductivity curve and soil water, showing high slope in the range close to saturation ) favors the AHFO a most suitable sensor due to its ability to measure the variable at small time and length intervals. Thus, it is possible to obtain accurate and a large number of data to be used to estimate the hydraulic conductivity curve from de water flow general equation by numerical methods. Results are promising and showed the feasibility of this technique to estimate the hydraulic conductivity curve for subsaturated soils .

New CATV fiber-to-the-subscriber architectures

NASA Astrophysics Data System (ADS)

Kim, Gary

1991-01-01

Although the cable television industry has seriously proposed the widespread use of optical fiber technology as the foundation of its networks only since 1988 an important financial watershed already has been reached. Based on stunningly rapid AM technology developments and new research by industry engineers the CATV industry has already reached the point where building new optical trunk is cheaper than building conventional coaxial cable plant. Although as recently as 1988 it might have seemed preposterous to suggest that the financial crossover point between optical media and copper media would soon be reached that indeed has occurred. Using a topology dubbed the " fiber trunk and feeder engineers at American Television Communications the second-largest U. S. CATV operator have demonstrated that it is currently feasible to build new optical fiber trunking networks at costs equal to or less than conventional 450-MHz coaxial cable plant. Installation of the first such network already is underway and it is expected that the significant change in fiber economics will further spur the already-heady pace of fiber introduction in the CATV industry. That in turn will create new types of networks with topologies resembling telephone " star" networks more than conventional " tree-and-branch" systems. The new optically-based networks will be far more reliable more flexible and better adapted to signal switching than conventional CATV networks have been. Although the new networks will be put into place

Optical Fiber In The Loop: Features And Applications

NASA Astrophysics Data System (ADS)

Shariati, Ross

1986-01-01

It is expected that there would be various demands for digital capacity, from a few kilobits per second for such services as facsimile, data entry, and provision of audio and graphic for teleconferencing, to about 56Kb/sec for electronic mail and integrated work stations, and higher speeds for cable television, high resolution TV, and computer-aided engineering. Fiber optics has been proven-in from an economic standpoint to provide the above-mentioned services. This is primarily due to the fact that in less than five years optical line rates have leaped from 45Mb/s to gigabit rates, therefore reducing the cost per DS3 of capacity, and the price of high quality fiber cable has taken a nosedive.

Novel electro-optical coupling technique for magnetic resonance-compatible positron emission tomography detectors.

PubMed

Olcott, Peter D; Peng, Hao; Levin, Craig S

2009-01-01

A new magnetic resonance imaging (MRI)-compatible positron emission tomography (PET) detector design is being developed that uses electro-optical coupling to bring the amplitude and arrival time information of high-speed PET detector scintillation pulses out of an MRI system. The electro-optical coupling technology consists of a magnetically insensitive photodetector output signal connected to a nonmagnetic vertical cavity surface emitting laser (VCSEL) diode that is coupled to a multimode optical fiber. This scheme essentially acts as an optical wire with no influence on the MRI system. To test the feasibility of this approach, a lutetium-yttrium oxyorthosilicate crystal coupled to a single pixel of a solid-state photomultiplier array was placed in coincidence with a lutetium oxyorthosilicate crystal coupled to a fast photomultiplier tube with both the new nonmagnetic VCSEL coupling and the standard coaxial cable signal transmission scheme. No significant change was observed in 511 keV photopeak energy resolution and coincidence time resolution. This electro-optical coupling technology enables an MRI-compatible PET block detector to have a reduced electromagnetic footprint compared with the signal transmission schemes deployed in the current MRI/PET designs.

A Fibre-Optic Communications Network for Teaching Clinical Medicine.

ERIC Educational Resources Information Center

Williams, Robin

1985-01-01

Describes an interactive television system based on fiber-optic communications technology which is used to facilitate participation by University of London medical students in lecture/tutorials by teachers in different hospital locations. Highlights include advantages of fiber-optics, cable manufacture and installation, opto-electronic interface,…

Optical Measurement of Mass Flow of a Two-Phase Fluid

NASA Technical Reports Server (NTRS)

Wiley, John; Pedersen, Kevin; Koman, Valentin; Gregory, Don

2008-01-01

An optoelectronic system utilizes wavelength-dependent scattering of light for measuring the density and mass flow of a two-phase fluid in a pipe. The apparatus was invented for original use in measuring the mass flow of a two-phase cryogenic fluid (e.g., liquid hydrogen containing bubbles of hydrogen gas), but underlying principles of operation can readily be adapted to non-cryogenic two-phase fluids. The system (see figure) includes a laser module, which contains two or more laser diodes, each operating at a different wavelength. The laser module also contains beam splitters that combine the beams at the various wavelengths so as to produce two output beams, each containing all of the wavelengths. One of the multiwavelength output beams is sent, via a multimode fiberoptic cable, to a transmitting optical coupler. The other multiwavelength output beam is sent, via another multimode fiber-optic cable, to a reference detector module, wherein fiber-optic splitters split the light into several multiwavelength beams, each going to a photodiode having a spectral response that is known and that differs from the spectral responses of the other photodiodes. The outputs of these photodiodes are digitized and fed to a processor, which executes an algorithm that utilizes the known spectral responses to convert the photodiode outputs to obtain reference laser-power levels for the various wavelengths. The transmitting optical coupler is mounted in (and sealed to) a hole in the pipe and is oriented at a slant with respect to the axis of the pipe. The transmitting optical coupler contains a collimating lens and a cylindrical lens that form the light emerging from the end of the fiber-optic cable into a fan-shaped beam in a meridional plane of the pipe. Receiving optical couplers similar to the transmitting optical couplers are mounted in the same meridional plane at various longitudinal positions on the opposite side of the pipe, approximately facing the transmitting optical coupler along the same slant. Light collected by each receiving optical coupler is sent, via a multimode fiber-optic cable, to a detector module similar to the reference detector module. The outputs of the photodiodes in each detector module are digitized and processed, similarly to those of the reference detector module, to obtain indications of the amounts of light of each wavelength scattered to the corresponding receiving position. The value for each wavelength at each position is also normalized to the reference laser-power level for that wavelength. From these normalized values, the density and the mass flow rate of the fluid are estimated.

Monitoring of Concrete Structures Using Ofdr Technique

NASA Astrophysics Data System (ADS)

Henault, J. M.; Salin, J.; Moreau, G.; Delepine-Lesoille, S.; Bertand, J.; Taillade, F.; Quiertant, M.; Benzarti, K.

2011-06-01

Structural health monitoring is a key factor in life cycle management of infrastructures. Truly distributed fiber optic sensors are able to provide relevant information on large structures, such as bridges, dikes, nuclear power plants or nuclear waste disposal facilities. The sensing chain includes an optoelectronic unit and a sensing cable made of one or more optical fibers. A new instrument based on Optical Frequency Domain Reflectometry (OFDR), enables to perform temperature and strain measurements with a centimeter scale spatial resolution over hundred of meters and with a level of precision equal to 1 μstrain and 0.1 °C. Several sensing cables are designed with different materials targeting to last for decades in a concrete aggressive environment and to ensure an optimal transfer of temperature and strain from the concrete matrix to the optical fiber. Tests were carried out by embedding various sensing cables into plain concrete specimens and representative-scale reinforced concrete structural elements. Measurements were performed with an OFDR instrument; meanwhile, mechanical solicitations were imposed to the concrete element. Preliminary experiments are very promising since measurements performed with distributed sensing system are comparable to values obtained with conventional sensors used in civil engineering and with the Strength of Materials Modelling. Moreover, the distributed sensing system makes it possible to detect and localize cracks appearing in concrete during the mechanical loading.

Fiber optic sensors for nuclear power plant applications

NASA Astrophysics Data System (ADS)

Kasinathan, Murugesan; Sosamma, Samuel; BabuRao, Chelamchala; Murali, Nagarajan; Jayakumar, Tammana

2012-05-01

Studies have been carried out for application of Raman Distributed Temperature Sensor (RDTS) in Nuclear Power Plants (NPP). The high temperature monitoring in sodium circuits of Fast Breeder Reactor (FBR) is important. It is demonstrated that RDTS can be usefully employed in monitoring sodium circuits and in tracking the percolating sodium in the surrounding insulation in case of any leak. Aluminum Conductor Steel Reinforced (ACSR) cable is commonly used as overhead power transmission cable in power grid. The suitability of RDTS for detecting defects in ACSR overhead power cable, is also demonstrated.

Bidirectional fiber-IVLLC and fiber-wireless convergence system with two orthogonally polarized optical sidebands.

PubMed

Lu, Hai-Han; Wu, Hsiao-Wen; Li, Chung-Yi; Ho, Chun-Ming; Yang, Zih-Yi; Cheng, Ming-Te; Lu, Chang-Kai

2017-05-01

A bidirectional fiber-invisible laser light communication (IVLLC) and fiber-wireless convergence system with two orthogonally polarized optical sidebands for hybrid cable television (CATV)/millimeter-wave (MMW)/baseband (BB) signal transmission is proposed and experimentally demonstrated. Two optical sidebands generated by a 60-GHz MMW signal are orthogonally polarized and separated into different polarizations. These orthogonally polarized optical sidebands are delivered over a 40-km single-mode fiber (SMF) transport to effectually reduce the fiber dispersion induced by a 40-km SMF transmission and the distortion caused by the parallel polarized optical sidebands. To the best of our knowledge, this work is the first to adopt two orthogonally polarized optical sidebands in a bidirectional fiber-IVLLC and fiber-wireless convergence system to reduce fiber dispersion and distortion effectually. Good carrier-to-noise ratio, composite second order, composite triple beat, and bit error rate (BER) are achieved for downlink transmission at a 40-km SMF operation and a 100-m free-space optical (FSO) link/3-m RF wireless transmission. For up-link transmission, good BER performance is acquired over a 40-km SMF transport and a 100-m FSO link. The approach presented in this work signifies the advancements in the convergence of SMF-based backbone and optical/RF wireless-based feeder.

Raman fiber optic probe assembly for use in hostile environments

DOEpatents

Schmucker, John E.; Falk, Jon C.; Archer, William B.; Blasi, Raymond J.

2000-01-01

This invention provides a device for Raman spectroscopic measurement of composition and concentrations in a hostile environment by the use of a first fiber optic as a means of directing high intensity monochromatic light from a laser to the hostile environment and a second fiber optic to receive the lower intensity scattered light for transmittal to a monochromator for analysis. To avoid damage to the fiber optics, they are protected from the hostile environment. A preferred embodiment of the Raman fiber optic probe is able to obtain Raman spectra of corrosive gases and solutions at temperatures up to 600.degree. F. and pressures up to 2000 psi. The incident exciting fiber optic cable makes an angle of substantially 90.degree. with the collecting fiber optic cable. This 90.degree. geometry minimizes the Rayleigh scattering signal picked up by the collecting fiber, because the intensity of Rayleigh scattering is lowest in the direction perpendicular to the beam path of the exciting light and therefore a 90.degree. scattering geometry optimizes the signal to noise ratio.

Optical Intrabuilding and Interbuilding Distribution Networks.

ERIC Educational Resources Information Center

Hull, Joseph A.

Fiber optics communication technology is a potential competitive alternative to coaxial cable and shielded twisted pairlines as a wide-band communications medium. Pilot demonstrations by public institutions such as the health care delivery system can test the application of this new technology. Fiber optic networks may have the potential to be…

Material Selection for Cable Gland to Improved Reliability of the High-hazard Industries

NASA Astrophysics Data System (ADS)

Vashchuk, S. P.; Slobodyan, S. M.; Deeva, V. S.; Vashchuk, D. S.

2018-01-01

The sealed cable glands (SCG) are available to ensure safest connection sheathed single wire for the hazard production facility (nuclear power plant and others) the same as pilot cable, control cables, radio-frequency cables et al. In this paper, we investigate the specifics of the material selection of SCG with the express aim of hazardous man-made facility. We discuss the safe working conditions for cable glands. The research indicates the sintering powdered metals cables provide the reliability growth due to their properties. A number of studies have demonstrated the verification of material selection. On the face of it, we make findings indicating that double glazed sealed units could enhance reliability. We had evaluated sample reliability under fire conditions, seismic load, and pressure containment failure. We used the samples mineral insulated thermocouple cable.

Determining Remaining Useful Life of Aging Cables in Nuclear Power Plants – Interim Study FY13

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simmons, Kevin L.; Fifield, Leonard S.; Westman, Matthew P.

2013-09-27

The most important criterion for cable performance is its ability to withstand a design-basis accident. With nearly 1000 km of power, control, instrumentation, and other cables typically found in an NPP, it would be a significant undertaking to inspect all of the cables. Degradation of the cable jacket, electrical insulation, and other cable components is a key issue that is likely to affect the ability of the currently installed cables to operate safely and reliably for another 20 to 40 years beyond the initial operating life. The development of one or more nondestructive evaluation (NDE) techniques and supporting models thatmore » could assist in determining the remaining life expectancy of cables or their current degradation state would be of significant interest. The ability to nondestructively determine material and electrical properties of cable jackets and insulation without disturbing the cables or connections has been deemed essential. Currently, the only technique accepted by industry to measure cable elasticity (the gold standard for determining cable insulation degradation) is the indentation measurement. All other NDE techniques are used to find flaws in the cable and do not provide information to determine the current health or life expectancy. There is no single NDE technique that can satisfy all of the requirements needed for making a life-expectancy determination, but a wide range of methods have been evaluated for use in NPPs as part of a continuous evaluation program. The commonly used methods are indentation and visual inspection, but these are only suitable for easily accessible cables. Several NDE methodologies using electrical techniques are in use today for flaw detection but there are none that can predict the life of a cable. There are, however, several physical and chemical ptoperty changes in cable insulation as a result of thermal and radiation damage. In principle, these properties may be targets for advanced NDE methods to provide early warning of aging and degradation. Examples of such key indicators include changes in chemical structure, mechanical modulus, and dielectric permittivity. While some of these indicators are the basis of currently used technologies, there is a need to increase the volume of cable that may be inspected with a single measurement, and if possible, to develop techniques for in-situ inspection (i.e., while the cable is in operation). This is the focus of the present report.« less

ISS Fiber Optic Failure Investigation Root Cause Report

NASA Technical Reports Server (NTRS)

Leidecker, Henning; Plante, Jeannette

2000-01-01

In August of 1999, Boeing Corporation (Boeing) engineers began investigating failures of optical fiber being used on International Space Station flight hardware. Catastrophic failures of the fiber were linked to a defect in the glass fiber. Following several meetings of Boeing and NASA engineers and managers, Boeing created and led an investigation team, which examined the reliability of the cable installed in the U.S. Lab. NASA Goddard Space Flight Center's Components Technologies and Radiation Effects Branch (GSFC) led a team investigating the root cause of the failures. Information was gathered from: regular telecons and other communications with the investigation team, investigative trips to the cable distributor's plant, the cable manufacturing plant and the fiber manufacturing plant (including a review of build records), destructive and non-destructive testing, and expertise supplied by scientists from Dupont, and Lucent-Bell Laboratories. Several theories were established early on which were not able to completely address the destructive physical analysis and experiential evidence. Lucent suggested hydrofluoric acid (HF) etching of the glass and successfully duplicated the "rocket engine" defect. Strength testing coupled with examination of the low strength break sites linked features in the polyimide coating with latent defect sites. The information provided below explains what was learned about the susceptibility of the pre-cabled fiber to failure when cabled as it was for Space Station and the nature of the latent defects.

Impact of wave propagation delay on latency in optical communication systems

NASA Astrophysics Data System (ADS)

Kawanishi, Tetsuya; Kanno, Atsushi; Yoshida, Yuki; Kitayama, Ken-ichi

2012-12-01

Latency is an important figure to describe performance of transmission systems for particular applications, such as data transfer for earthquake early warning, transaction for financial businesses, interactive services such as online games, etc. Latency consists of delay due to signal processing at nodes and transmitters, and of signal propagation delay due to propagation of electromagnetic waves. The lower limit of the latency in transmission systems using conventional single mode fibers (SMFs) depends on wave propagation speed in the SMFs which is slower than c. Photonic crystal fibers, holly fibers and large core fibers can have low effective refractive indices, and can transfer light faster than in SMFs. In free-space optical systems, signals propagate with the speed c, so that the latency could be smaller than in optical fibers. For example, LEO satellites would transmit data faster than optical submarine cables, when the transmission distance is longer than a few thousand kilometers. This paper will discuss combination of various transmission media to reduce negative impact of the latency, as well as applications of low-latency systems.

3D beam shape estimation based on distributed coaxial cable interferometric sensor

NASA Astrophysics Data System (ADS)

Cheng, Baokai; Zhu, Wenge; Liu, Jie; Yuan, Lei; Xiao, Hai

2017-03-01

We present a coaxial cable interferometer based distributed sensing system for 3D beam shape estimation. By making a series of reflectors on a coaxial cable, multiple Fabry-Perot cavities are created on it. Two cables are mounted on the beam at proper locations, and a vector network analyzer (VNA) is connected to them to obtain the complex reflection signal, which is used to calculate the strain distribution of the beam in horizontal and vertical planes. With 6 GHz swept bandwidth on the VNA, the spatial resolution for distributed strain measurement is 0.1 m, and the sensitivity is 3.768 MHz mɛ -1 at the interferogram dip near 3.3 GHz. Using displacement-strain transformation, the shape of the beam is reconstructed. With only two modified cables and a VNA, this system is easy to implement and manage. Comparing to optical fiber based sensor systems, the coaxial cable sensors have the advantage of large strain and robustness, making this system suitable for structure health monitoring applications.

Current Status and Tasks in Development of Cable Recycling Technology

NASA Astrophysics Data System (ADS)

Ezure, Takashi; Goto, Kazuhiko

This paper shows current status and tasks in development of cable recycling technology and it’s items to be solved. Electric cable recycle system has been activated especially for copper conductor recycle in Japan. Previously removed cable coverings materials were mainly land filled. But landfill capacity is decreased and limited in recent years, at the same time, recycle technology was highly developed. A cable recycle technology has 4 tasks. (1) Applying new high efficiency separation system instead of electrostatic and gravity methods to classify mixed various kind of plastics materials including recently developed ecological material (ex PE, PVC, Rubber), (2) Removing heavy metal, especially lead from PVC material, (3) Treatment of optical glass fiber core, which has possibility going to be harmful micro particles, and (4) Establishment of social recycle system for electric wire and cable. Taking action for these tasks shall be proceeded under environmentally sensitive technology together with local government, user, manufacturer, and waste-disposal company on cost performance basis.

Literature review of environmental qualification of safety-related electric cables: Summary of past work. Volume 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Subudhi, M.

1996-04-01

This report summarizes the findings from a review of published documents dealing with research on the environmental qualification of safety-related electric cables used in nuclear power plants. Simulations of accelerated aging and accident conditions are important considerations in qualifying the cables. Significant research in these two areas has been performed in the US and abroad. The results from studies in France, Germany, and Japan are described in this report. In recent years, the development of methods to monitor the condition of cables has received special attention. Tests involving chemical and physical examination of cable`s insulation and jacket materials, and electricalmore » measurements of the insulation properties of cables are discussed. Although there have been significant advances in many areas, there is no single method which can provide the necessary information about the condition of a cable currently in service. However, it is possible that further research may identify a combination of several methods that can adequately characterize the cable`s condition.« less

7 CFR 1755.200 - RUS standard for splicing copper and fiber optic cables.

Code of Federal Regulations, 2011 CFR

2011-01-01

... making an OTDR test at the same time a splice is being fused. (7) Cable preparation. (i) Engineering work.... Reagent grade isopropyl alcohol is a commonly used cleaning solvent. (ii) A tissue or cotton ball shall be... using a clean tissue or cotton ball for each coated fiber. Caution shall be exercised to avoid removing...

Investigation of the strength of shielded and unshielded underwater electrical cables

NASA Astrophysics Data System (ADS)

Glowe, D. E.; Arnett, S. L.

1981-09-01

The mechanical properties of shielded and unshielded submarine cables (MIL-C-915/8E) were investigated to determine the effect of shielding on cable life, performance, and reliability. Ten cables (five shielded and five unshielded) were selected for laboratory evaluation. A mission profile was developed to establish the mechanical stress limits that cables must endure in service and a test sequence designed to measure tensile strength, flexural abrasion endurance, crush resistance, creep under static tension, and performance in a hull-stuffing tube. The results of this program showed that: (1) DSS-2 cable does not have adequate tensile strength and should have a strength member added. DSS-3 and larger cables have adequate tensile strength with or without the shield; (2) Unshielded DSS-3 type cable does not perform satisfactorily in hull-stuffing tubes; (3) Shielding is not required to meet mission profile specifications for cable crush or flexural abrasion resistance; (4) Construction parameters other than shielding can significantly affect mechanical performance of cable; (5) Unshielded cable construction can result in increased reliability since it permits a thicker single-jacket construction; and (6) Unshielded cable construction can reduce the cost of cable by 8 to 20 percent.

Measurement of the optical fiber numeric aperture exposed to thermal and radiation aging

NASA Astrophysics Data System (ADS)

Vanderka, Ales; Bednarek, Lukas; Hajek, Lukas; Latal, Jan; Poboril, Radek; Zavodny, Petr; Vasinek, Vladimir

2016-12-01

This paper deals with the aging of optical fibers influenced by temperature and radiation. There are analyzed changes in the structure of the optical fiber, related to the propagation of light in the fiber structure. In this case for numerical aperture. For experimental measurement was used MM fiber OM1 with core diameter 62.5 μm, cladding diameter 125 μm in 2.8 mm secondary coating. Aging of the optical fiber was achieved with dry heat and radiation. For this purpose, we were using a temperature chamber with a stable temperature of 105 °C where the cables after two months. Cables were then irradiated with gamma radiation 60Co in doses of 1.5 kGy and then 60 kGy. These conditions simulated 50 years aging process of optical cables. According to European Standard EN 60793-1-43:2015 was created the automatic device for angular scan working with LabVIEW software interface. Numerical aperture was tested at a wavelength of 850 nm, with an output power 1 mW. Scanning angle was set to 50° with step 0.25°. Numerical aperture was calculated from the position where power has fallen from maximal power at e2 power. The measurement of each sample was performed 10 hours after thermal and radiation aging. The samples were subsequently tested after six months from the last irradiation. In conclusion, the results of the experiment were analyzed and compared.

Laser Communications and Fiber Optics Lab Manual. High-Technology Training Module.

ERIC Educational Resources Information Center

Biddick, Robert

This laboratory training manual on laser communications and fiber optics may be used in a general technology-communications course for ninth graders. Upon completion of this exercise, students achieve the following goals: match concepts with laser communication system parts; explain advantages of fiber optic cable over conventional copper wire;…

Heated fiber optic distributed temperature sensing: a tool for measuring soil water content

NASA Astrophysics Data System (ADS)

Rodriguez-Sinobas, Leonor; Zubelzu, Sergio; Sánchez-Calvo, Raúl; Horcajo, Daniel

2016-04-01

The use of Distributed Fiber Optic Temperature Measurement (DFOT) method for estimating temperature variation along a cable of fiber optic has been assessed in multiple environmental applications. Recently, the application of DFOT combined with an active heating pulses technique has been reported as a sensor to estimate soil moisture. This method applies a known amount of heat to the soil and monitors the temperature evolution, which mainly depends on the soil moisture content . This study presents the application of the Active Heated DFOT method to determine the soil water retention curve under experimental conditions. The experiment was conducted in a rectangular methacrylate box of 2.5 m x 0.25 m x 0.25 m which was introduced in a larger box 2.8 m x 0.3 m x 0.3 m of the same material. The inner box was filled with a sandy loamy soil collected from the nearest garden and dried under ambient temperature for 30 days. Care was taking to fill up the box maintaining the soil bulk density determined "in-situ". The cable was deployed along the box at 10 cm depth. At the beginning of the experiment, the box was saturated bottom-up, by filling the outer box with water, and then it kept dried for two months. The circulation of heated air at the bottom box accelerated the drying process. In addition, fast growing turf was also sowed to dry it fast. The DTS unit was a SILIXA ULTIMA SR (Silixa Ltd, UK) and has spatial and temporal resolution of 0.29 m and 5 s, respectively. In this study, heat pulses of 7 W/m for 2 1/2 min were applied uniformly along the fiber optic cable and the thermal response on an adjacent cable was monitored in different soil water status. Then, the heating and drying phase integer (called Tcum) was determined following the approach of Sayde et al., (2010). For each water status,  was measured by the gravimetric method in several soil samples collected in three box locations at the same depth that the fiber optic cable and after each heat pulse. Finally, the soil water retention curve was estimated by fitting pairs of Tcum- values. Results showed the feasibility of heated fiber optics with distributed temperature sensing to estimate soil water content, and suggest its potential for its application under field conditions

Computer-Aided Engineering Of Cabling

NASA Technical Reports Server (NTRS)

Billitti, Joseph W.

1989-01-01

Program generates data sheets, drawings, and other information on electrical connections. DFACS program, centered around single data base, has built-in menus providing easy input of, and access to, data for all personnel involved in system, subsystem, and cabling. Enables parallel design of circuit-data sheets and drawings of harnesses. Also recombines raw information to generate automatically various project documents and drawings, including index of circuit-data sheets, list of electrical-interface circuits, lists of assemblies and equipment, cabling trees, and drawings of cabling electrical interfaces and harnesses. Purpose of program to provide engineering community with centralized data base for putting in, and gaining access to, functional definition of system as specified in terms of details of pin connections of end circuits of subsystems and instruments and data on harnessing. Primary objective to provide instantaneous single point of interchange of information, thus avoiding

Challenges in Ecohydrological Monitoring at Soil-Vegetation Interfaces: Exploiting the Potential for Fibre Optic Technologies

NASA Astrophysics Data System (ADS)

Chalari, A.; Ciocca, F.; Krause, S.; Hannah, D. M.; Blaen, P.; Coleman, T. I.; Mondanos, M.

2015-12-01

The Birmingham Institute of Forestry Research (BIFoR) is using Free-Air Carbon Enrichment (FACE) experiments to quantify the long-term impact and resilience of forests into rising atmospheric CO2 concentrations. The FACE campaign critically relies on a successful monitoring and understanding of the large variety of ecohydrological processes occurring across many interfaces, from deep soil to above the tree canopy. At the land-atmosphere interface, soil moisture and temperature are key variables to determine the heat and water exchanges, crucial to the vegetation dynamics as well as to groundwater recharge. Traditional solutions for monitoring soil moisture and temperature such as remote techniques and point sensors show limitations in fast acquisition rates and spatial coverage, respectively. Hence, spatial patterns and temporal dynamics of heat and water fluxes at this interface can only be monitored to a certain degree, limiting deeper knowledge in dynamically evolving systems (e.g. in impact of growing vegetation). Fibre optics Distributed Temperature Sensors (DTS) can measure soil temperatures at high spatiotemporal resolutions and accuracy, along kilometers of optical cable buried in the soil. Heat pulse methods applied to electrical elements embedded in the optical cable can be used to obtain the soil moisture. In July 2015 a monitoring system based on DTS has been installed in a recently forested hillslope at BIFoR in order to quantify high-resolution spatial patterns and high-frequency temporal dynamics of soil heat fluxes and soil moisture conditions. Therefore, 1500m of optical cables have been carefully deployed in three overlapped loops at 0.05m, 0.25m and 0.4m from the soil surface and an electrical system to send heat pulses along the optical cable has been developed. This paper discussed both, installation and design details along with first results of the soil moisture and temperature monitoring carried out since July 2015. Moreover, interpretations of the collected data to investigate the impact on soil moisture dynamics of i) forest evolution (long timescale), (ii) seasonality and, (iii) high-frequency forcing, are discussed.

Development of a comprehensive inventory management system for underground fiber optic conduits.

DOT National Transportation Integrated Search

2013-03-01

Major State Departments of Transportation operate and maintain networks of thousands of miles of conduits, many : carrying fiber optic cables that are vital to State communication systems. These conduits are located alongside or : across highways and...

76 FR 30739 - Notice of Availability of the Record of Decision for Southern California Edison's Eldorado...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-26

... connector hub for solar energy generated in the Ivanpah Valley area. A fiber optics telecommunications cable will be located on the new transmission towers and an additional fiber optics pathway ROW is also...

Arrangement for multiplexing and intensity splitting light beams for interface into fiber optic cables

DOEpatents

Johnson, Steve A.

1990-01-01

An arrangement especially suitable for use in a laser apparatus for converting a plurality of different input light beams, for example copper vapor laser beams, into a plurality of substantially identical light beams is disclosed herein. This arrangement utilizes an optical mixing bar which is preferably integrally formed as a single unit and which includes a main body for mixing light therein, a flat input surface on one end of the main body, and a multi-faceted output face on the opposite end of the main body. This arrangement also includes means for directing the plurality of different input light beams onto the input face of the mixing base, whereby to cause the different beams to mix within the main body of the mixing bar and exit the latter from its multi-faceted output face as the desired plurality of substantially identical output beams.

Fiber optic TV direct

NASA Technical Reports Server (NTRS)

Kassak, John E.

1991-01-01

The objective of the operational television (OTV) technology was to develop a multiple camera system (up to 256 cameras) for NASA Kennedy installations where camera video, synchronization, control, and status data are transmitted bidirectionally via a single fiber cable at distances in excess of five miles. It is shown that the benefits (such as improved video performance, immunity from electromagnetic interference and radio frequency interference, elimination of repeater stations, and more system configuration flexibility) can be realized if application of the proven fiber optic transmission concept is used. The control system will marry the lens, pan and tilt, and camera control functions into a modular based Local Area Network (LAN) control network. Such a system does not exist commercially at present since the Television Broadcast Industry's current practice is to divorce the positional controls from the camera control system. The application software developed for this system will have direct applicability to similar systems in industry using LAN based control systems.

Large motion high cycle high speed optical fibers for space based applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stromberg, Peter G.; Tandon, Rajan; Gibson, Cory S.

2014-10-01

Future remote sensing applications will require higher resolution and therefore higher data rates (up to perhaps 100 gigabits per second) while achieving lower mass and cost. A current limitation to the design space is high speed high bandwidth data does not cross movable gimbals because of cabling issues. This requires the detectors to be off gimbal. The ability to get data across the gimbal would open up efficiencies in designs where the detectors and the electronics can be placed anywhere on the system. Fiber optic cables provide light weight high speed high bandwidth connections. Current options are limited to 20,000more » cycles as opposed to the 1,000,000 cycles needed for future space based applications. To extend this to the million+ regime, requires a thorough understanding of the failure mechanisms and the materials, proper selection of materials (e.g., glass and jacket material) allowable geometry changes to the cable, radiation hardness, etc.« less

And They're Off! The Race to Fiber Optics.

ERIC Educational Resources Information Center

Lewis, Joan E.

1993-01-01

Describes fiber optic technology and discusses its use in distance learning and educational reform. Highlights include the quality of communications transmission systems; costs; Federal Communications Commission rules and regulations; cable television; networks, including the National Research and Education Network (NREN); government versus…

Adjustable Optical-Fiber Attenuator

NASA Technical Reports Server (NTRS)

Buzzetti, Mike F.

1994-01-01

Adjustable fiber-optic attenuator utilizes bending loss to reduce strength of light transmitted along it. Attenuator functions without introducing measurable back-reflection or insertion loss. Relatively insensitive to vibration and changes in temperature. Potential applications include cable television, telephone networks, other signal-distribution networks, and laboratory instrumentation.

Multi-access laser communications terminal

NASA Technical Reports Server (NTRS)

1992-01-01

The Optical Multi-Access (OMA) Terminal is capable of establishing up to six simultaneous high-data-rate communication links between low-Earth-orbit satellites and a host satellite at synchronous orbit with only one 16-inch-diameter antenna on the synchronous satellite. The advantage over equivalent RF systems in space weight, power, and swept volume is great when applied to NASA satellite communications networks. A photograph of the 3-channel prototype constructed under the present contract to demonstrate the feasibility of the concept is presented. The telescope has a 10-inch clear aperture and a 22 deg full field of view. It consists of 4 refractive elements to achieve a telecentric focus, i.e., the focused beam is normal to the focal plane at all field angles. This feature permits image pick-up optics in the focal plane to track satellite images without tilting their optic axes to accommodate field angle. The geometry of the imager-pick-up concept and the coordinate system of the swinging arm and disk mechanism for image pick-up are shown. Optics in the arm relay the telescope focus to a communications and tracking receiver and introduce the transmitted beacon beam on a path collinear with the receive path. The electronic circuits for the communications and tracking receivers are contained on the arm and disk assemblies and relay signals to an associated PC-based operator's console for control of the arm and disk motor drive through a flexible cable which permits +/- 240 deg travel for each arm and disk assembly. Power supplies and laser transmitters are mounted in the cradle for the telescope. A single-mode fiber in the cable is used to carry the laser transmitter signal to the arm optics. The promise of the optical multi-access terminal towards which the prototype effort worked is shown. The emphasis in the prototype development was the demonstration of the unique aspect of the concept, and where possible, cost avoidance compromises were implemented in areas already proven on other programs. The design details are described in section 2, the prototype test results in section 3, additional development required in section 4, and conclusions in section 5.

Health monitoring of Binzhou Yellow River highway bridge using fiber Bragg gratings

NASA Astrophysics Data System (ADS)

Ou, Jinping; Zhao, Xuefeng; Li, Hui; Zhou, Zhi; Zhang, Zhichun; Wang, Chuan

2005-05-01

Binzhou yellow river Highway Bridge with 300 meter span and 768 meter length is located in the Shandong province of China and is the first cable stayed bridge with three towers along the yellow river, one of the biggest rivers in China. In order to monitoring the strain and temperature of the bridge and evaluate the health condition, one fiber Bragg grating sensing network consists of about one hundred and thirty FBG sensors mounted in 31 monitoring sections respectively, had been built during three years time. Signal cables of sensors were led to central control room located near the main tower. One four-channel FBG interrogator was used to read the wavelengths from all the sensors, associated with four computer-controlled optic switches connected to each channel. One program was written to control the interrogator and optic switches simultaneously, and ensure signal input precisely. The progress of the monitoring can be controlled through the internet. The sensors embedded were mainly used to monitor the strain and temperature of the steel cable and reinforced concrete beam. PE jacket opening embedding technique of steel cable had been developed to embed FBG sensors safely, and ensure the reliability of the steel cable opened at the same time. Data obtained during the load test can show the strain and temperature status of elements were in good condition. The data obtained via internet since the bridge's opening to traffic shown the bridge under various load such as traffic load, wind load were in good condition.

Status of fiberoptics technology for propulsion control systems

NASA Technical Reports Server (NTRS)

Baumbick, R. J.

1982-01-01

Optical sensors and optically controlled actuators for use in airbreathing engine control systems are discussed. The environmental conditions in which the aircraft will operate require the fiberoptic cables and optical connectors to perform reliably at temperatures over the -55 C to 260 C range. The status of fiberoptics technology for operation in this environment is reviewed.

Small form factor optical fiber connector evaluation for harsh environments

NASA Astrophysics Data System (ADS)

Ott, Melanie N.; Thomes, W. Joe, Jr.; Chuska, Richard F.; Switzer, Robert; Blair, Diana E.

2011-09-01

For the past decade NASA programs have utilized the Diamond AVIM connector for optical fiber assemblies on space flight instrumentation. These connectors have been used in communications, sensing and LIDAR systems where repeatability and high performance are required. Recently Diamond has released a smaller form factor optical fiber connector called the "Mini-AVIM" which although more compact still includes the tight tolerances and the ratcheting feature of the heritage AVIM. NASA Goddard Space Flight Center Photonics Group in the Parts, Packaging and Assembly Technologies Office has been performing evaluations of this connector to determine how it compares to the performance of the AVIM connector and to assess its feasibility for harsh environmental applications. Vibration and thermal testing were performed on the Mini-AVIM with both multi-mode and single-mode optical fiber using insitu optical transmission monitoring. Random vibration testing was performed using typical launch condition profiles for most NASA missions but extended to 35 Grms, which is much higher than most requirements. Thermal testing was performed incrementally up to a range of -55°C to +125°C. The test results include both unjacketed fiber and cabled assembly evaluations. The data presented here indicate that the Mini-AVIM provides a viable option for small form factor applications that require a high performance optical fiber connector.

SU-E-QI-15: Single Point Dosimetry by Means of Cerenkov Radiation Energy Transfer (CRET)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Volotskova, O; Jenkins, C; Xing, L

2014-06-15

Purpose: Cerenkov light is generated when a charged particles with energy greater then 250 keV, moves faster than the speed of light in a given medium. Both x-ray photons and electrons produce optical Cerenkov photons during the static megavoltage linear accelerator (LINAC) operational mode. Recently, Cerenkov radiation gained considerable interest as possible candidate as a new imaging modality. Optical signals generated by Cerenkov radiation may act as a surrogate for the absorbed superficial radiation dose. We demonstrated a novel single point dosimetry method for megavoltage photon and electron therapy utilizing down conversion of Cerenkov photons. Methods: The custom build signalmore » characterization system was used: a sample holder (probe) with adjacent light tight compartments was connected via fiber-optic cables to a photon counting photomultiplier tube (PMT). One compartment contains a medium only while the other contains medium and red-shifting nano-particles (Q-dots, nanoclusters). By taking the difference between the two signals (Cerenkov photons and CRET photons) we obtain a measure of the down-converted light, which we expect to be proportional to dose as measured with an adjacent ion chamber. Experimental results are compared to Monte Carlo simulations performed using the GEANT4 code. Results: The signal correlation between CR signal, CRET readings and dose produced by LINAC at a single point were investigated. The experimental results were compared with simulations. The dose linearity, signal to noise ratio and dose rate dependence were tested with custom build CRET based probe. Conclusion: Performance characteristics of the proposed single point CRET based probe were evaluated. The direct use of the induced Cerenkov emission and CRET in an irradiated single point volume as an indirect surrogate for the imparted dose was investigated. We conclude that CRET is a promising optical based dosimetry method that offers advantages over those already proposed.« less

Solutions for transients in arbitrarily branching cables: III. Voltage clamp problems.

PubMed

Major, G

1993-07-01

Branched cable voltage recording and voltage clamp analytical solutions derived in two previous papers are used to explore practical issues concerning voltage clamp. Single exponentials can be fitted reasonably well to the decay phase of clamped synaptic currents, although they contain many underlying components. The effective time constant depends on the fit interval. The smoothing effects on synaptic clamp currents of dendritic cables and series resistance are explored with a single cylinder + soma model, for inputs with different time courses. "Soma" and "cable" charging currents cannot be separated easily when the soma is much smaller than the dendrites. Subtractive soma capacitance compensation and series resistance compensation are discussed. In a hippocampal CA1 pyramidal neurone model, voltage control at most dendritic sites is extremely poor. Parameter dependencies are illustrated. The effects of series resistance compound those of dendritic cables and depend on the "effective capacitance" of the cell. Plausible combinations of parameters can cause order-of-magnitude distortions to clamp current waveform measures of simulated Schaeffer collateral inputs. These voltage clamp problems are unlikely to be solved by the use of switch clamp methods.

Fiber Optic Distributed Temperature Sensing of Recharge Basin Percolation Dynamics

NASA Astrophysics Data System (ADS)

Becker, M.; Allen, E. M.; Hutchinson, A.

2014-12-01

Infiltration (spreading) basins are a central component of managed aquifer and recovery operations around the world. The concept is simple. Water is percolated into an aquifer where it can be withdrawn at a later date. However, managing infiltration basins can be complicated by entrapped air in sediments, strata of low permeability, clogging of the recharge surface, and biological growth, among other factors. Understanding the dynamics of percolation in light of these complicating factors provides a basis for making management decisions that increase recharge efficiency. As an aid to understanding percolation dynamics, fiber optic distribute temperature sensing (DTS) was used to track heat as a tracer of water movement in an infiltration basin. The diurnal variation of temperature in the basin was sensed at depth. The time lag between the oscillating temperature signal at the surface and at depth indicated the velocity of water percolation. DTS fiber optic cables were installed horizontally along the basin and vertically in boreholes to measure percolation behavior. The horizontal cable was installed in trenches at 0.3 and 1 m depth, and the vertical cable was installed using direct push technology. The vertical cable was tightly wound to produce a factor of 10 increase in spatial resolution of temperature measurements. Temperature was thus measured every meter across the basin and every 10 cm to a depth of 10 m. Data from the trenched cable suggested homogeneous percolation across the basin, but infiltration rates were a function of stage indicating non-ideal percolation. Vertical temperature monitoring showed significant lateral flow in sediments underlying the basin both during saturation and operation of the basin. Deflections in the vertical temperature profile corresponded with fine grained layers identified in core samples indicating a transient perched water table condition. The three-dimensional flow in this relatively homogenous surficial geology calls into question the relevance of simple wetting models for predicting percolation behavior in infiltration basins.

Subsidence monitoring system for offshore applications: technology scouting and feasibility studies

NASA Astrophysics Data System (ADS)

Miandro, R.; Dacome, C.; Mosconi, A.; Roncari, G.

2015-11-01

Because of concern about possible impacts of hydrocarbon production activities on coastal-area environments and infrastructures, new hydrocarbon offshore development projects in Italy must submit a monitoring plan to Italian authorities to measure and analyse real-time subsidence evolution. The general geological context, where the main offshore Adriatic fields are located, is represented by young unconsolidated terrigenous sediments. In such geological environments, sea floor subsidence, caused by hydrocarbon extraction, is quite probable. Though many tools are available for subsidence monitoring onshore, few are available for offshore monitoring. To fill the gap ENI (Ente Nazionale Idrocarburi) started a research program, principally in collaboration with three companies, to generate a monitoring system tool to measure seafloor subsidence. The tool, according to ENI design technical-specification, would be a robust long pipeline or cable, with a variable or constant outside diameter (less than or equal to 100 mm) and interval spaced measuring points. The design specifications for the first prototype were: to detect 1 mm altitude variation, to work up to 100 m water depth and investigation length of 3 km. Advanced feasibility studies have been carried out with: Fugro Geoservices B.V. (Netherlands), D'Appolonia (Italy), Agisco (Italy). Five design (using three fundamental measurements concepts and five measurement tools) were explored: cable shape changes measured by cable strain using fiber optics (Fugro); cable inclination measured using tiltmeters (D'Appolonia) and measured using fiber optics (Fugro); and internal cable altitude-dependent pressure changes measured using fiber optics (Fugro) and measured using pressure transducers at discrete intervals along the hydraulic system (Agisco). Each design tool was analysed and a rank ordering of preferences was performed. The third method (measurement of pressure changes), with the solution proposed by Agisco, was deemed most feasible. Agisco is building the first prototype of the tool to be installed in an offshore field in the next few years. This paper describes design of instruments from the three companies to satisfy the design specification.

The use of distributed temperature sensing technology for monitoring wildland fire intensity and distribution.

NASA Astrophysics Data System (ADS)

Ochoa, C. G.; Cram, D.; Hatch, C. E.; Tyler, S. W.

2014-12-01

Distributed temperature sensing (DTS) technology offers a viable alternative for accurately measuring wildland fire intensity and distribution in real time applications. We conducted an experiment to test the use of DTS as an alternative technology to monitor prescribed fire temperatures in real time and across a broad spatial scale. The custom fiber-optic cable consisted of three fiber optic lines buffered by polyamide, copper, and polyvinyl chloride, respectively, each armored in a stainless steel tube backfilled with Nitrogen gas. The 150 m long cable was deployed in three different 20 by 26 m experimental plots of short-grass rangeland in central New Mexico. Cable was arranged to maximize coverage of the experimental plots and allow cross-comparison between two main parallel straight-line sections approximately 8 m apart. A DTS system recorded fire temperatures every three seconds and integrated every one meter. A series of five thermocouples attached to a datalogger were placed at selected locations along the cable and also recorded temperature data every three seconds on each fiber. Results indicate that in general there is good agreement between thermocouple-measured and DTS-measured temperatures. A close match in temperature between DTS and thermocouples was particularly observed during the rising limb but not so much during the decline. The metal armoring of the fiber-optic cable remained hot longer than the thermocouples after the flames had passed. The relatively short-duration, high-intensity, prescribed burn fire in each plot resulted in temperatures reaching up to 450 degrees Celsius. In addition, DTS data allow for illustration of the irregular nature of flame speed and travel path across the rangeland grasses, a phenomenon that was impossible to quantify without the use of this tool. This study adds to the understanding of using DTS as a new alternative tool for better characterizing wildland fire intensity, distribution and travel patterns, and establishes the baseline for expanding these test plot results to larger spatial scales.

Evaluation of critical nuclear power plant electrical cable response to severe thermal fire conditions

NASA Astrophysics Data System (ADS)

Taylor, Gabriel James

The failure of electrical cables exposed to severe thermal fire conditions are a safety concern for operating commercial nuclear power plants (NPPs). The Nuclear Regulatory Commission (NRC) has promoted the use of risk-informed and performance-based methods for fire protection which resulted in a need to develop realistic methods to quantify the risk of fire to NPP safety. Recent electrical cable testing has been conducted to provide empirical data on the failure modes and likelihood of fire-induced damage. This thesis evaluated numerous aspects of the data. Circuit characteristics affecting fire-induced electrical cable failure modes have been evaluated. In addition, thermal failure temperatures corresponding to cable functional failures have been evaluated to develop realistic single point thermal failure thresholds and probability distributions for specific cable insulation types. Finally, the data was used to evaluate the prediction capabilities of a one-dimension conductive heat transfer model used to predict cable failure.

Qualification of a truly distributed fiber optic technique for strain and temperature measurements in concrete structures

NASA Astrophysics Data System (ADS)

Henault, J. M.; Salin, J.; Moreau, G.; Delepine-Lesoille, S.; Bertand, J.; Taillade, F.; Quiertant, M.; Benzarti, K.

2011-04-01

Structural health monitoring is a key factor in life cycle management of infrastructures. Truly distributed fiber optic sensors are able to provide relevant information on large structures, such as nuclear power plants or nuclear waste disposal facilities. The sensing chain includes an optoelectronic unit and a sensing cable made of one or more optical fibers. A new instrument based on Optical Frequency Domain Reflectometry (OFDR), enables to perform temperature and strain measurements with a centimeter scale spatial resolution over hundred of meters and with a level of precision equal to 1 μ strain and 0.1 °C. Several sensing cables are designed with different materials targeting to last for decades, either embedded in the concrete or attached to the surface of the structure. They must ensure an optimal transfer of temperature and strain from the concrete matrix to the optical fiber. Based on the European guide FD CEN/TR 14748 "Non-destructive testing - Methodology for qualification of non-destructive tests", a qualification method was developed. Tests were carried out using various sensing cables embedded in the volume or fixed to the surface of plain concrete specimens and representative-scale reinforced concrete structural elements. Measurements were performed with an OFDR instrument, while mechanical solicitations were imposed to the concrete element. Preliminary experiments seem very promising since measurements performed with distributed sensing systems are found comparable to values obtained with conventional sensors used in civil engineering and with the Strength of Materials Modelling. Moreover, the distributed sensing system makes it possible to detect and localize cracks appearing in concrete during the mechanical loading.

Optical links in handheld multimedia devices

NASA Astrophysics Data System (ADS)

van Geffen, S.; Duis, J.; Miller, R.

2008-04-01

Ever emerging applications in handheld multimedia devices such as mobile phones, laptop computers, portable video games and digital cameras requiring increased screen resolutions are driving higher aggregate bitrates between host processor and display(s) enabling services such as mobile video conferencing, video on demand and TV broadcasting. Larger displays and smaller phones require complex mechanical 3D hinge configurations striving to combine maximum functionality with compact building volumes. Conventional galvanic interconnections such as Micro-Coax and FPC carrying parallel digital data between host processor and display module may produce Electromagnetic Interference (EMI) and bandwidth limitations caused by small cable size and tight cable bends. To reduce the number of signals through a hinge, the mobile phone industry, organized in the MIPI (Mobile Industry Processor Interface) alliance, is currently defining an electrical interface transmitting serialized digital data at speeds >1Gbps. This interface allows for electrical or optical interconnects. Above 1Gbps optical links may offer a cost effective alternative because of their flexibility, increased bandwidth and immunity to EMI. This paper describes the development of optical links for handheld communication devices. A cable assembly based on a special Plastic Optical Fiber (POF) selected for its mechanical durability is terminated with a small form factor molded lens assembly which interfaces between an 850nm VCSEL transmitter and a receiving device on the printed circuit board of the display module. A statistical approach based on a Lean Design For Six Sigma (LDFSS) roadmap for new product development tries to find an optimum link definition which will be robust and low cost meeting the power consumption requirements appropriate for battery operated systems.

Experimental research of "microcable in a microconduct" system stability to effect of freezing water

NASA Astrophysics Data System (ADS)

Andreev, Vladimir A.; Burdin, Vladimir A.; Nikulina, Tatiana G.; Alekhin, Ivan N.; Gavryushin, Sergey A.; Nikulin, Aleksey G.; Praporshchikov, Denis E.

2011-12-01

Results of experimental researches of "optical microcable in a microduct" system stability to effect of freezing water are presented. It is shown this system is steadier to water freezing in comparison to lighten optical cable in protective polymer tube.

Design for improved maintenance of the fiber-optic cable system (As carried out in a concurrent engineering environment)

NASA Astrophysics Data System (ADS)

Tremoulet, P. C.

The author describes a number of maintenance improvements in the Fiber Optic Cable System (FOCS). They were achieved during a production phase pilot concurrent engineering program. Listed in order of importance (saved maintenance time and material) by maintenance level, they are: (1) organizational level: improved fiber optic converter (FOC) BITE; (2) Intermediate level: reduced FOC adjustments from 20 to 2; partitioned FOC into electrical and optical parts; developed cost-effective fault isolation test points and test using standard test equipment; improved FOC chassis to have lower mean time to repair; and (3) depot level: revised test requirements documents (TRDs) for common automatic test equipment and incorporated ATE testability into circuit and assemblies and application-specific integrated circuits. These improvements met this contract's tailored logistics MIL-STD 1388-1A requirements of monitoring the design for supportability and determining the most effective support equipment. Important logistics lessons learned while accomplishing these maintainability and supportability improvements on the pilot concurrent engineering program are also discussed.

FLASH fly-by-light flight control demonstration results overview

NASA Astrophysics Data System (ADS)

Halski, Don J.

1996-10-01

The Fly-By-Light Advanced Systems Hardware (FLASH) program developed Fly-By-Light (FBL) and Power-By-Wire (PBW) technologies for military and commercial aircraft. FLASH consists of three tasks. Task 1 developed the fiber optic cable, connectors, testers and installation and maintenance procedures. Task 3 developed advanced smart, rotary thin wing and electro-hydrostatic (EHA) actuators. Task 2, which is the subject of this paper,l focused on integration of fiber optic sensors and data buses with cable plant components from Task 1 and actuators from Task 3 into centralized and distributed flight control systems. Both open loop and piloted hardware-in-the-loop demonstrations were conducted with centralized and distributed flight control architectures incorporating the AS-1773A optical bus, active hand controllers, optical sensors, optimal flight control laws in high speed 32-bit processors, and neural networks for EHA monitoring and fault diagnosis. This paper overviews the systems level testing conducted under the FLASH Flight Control task. Preliminary results are summarized. Companion papers provide additional information.

USSR Report Electronics and Electrical Engineering.

DTIC Science & Technology

1986-11-07

Porous Glass (I.K. Meshkovskiy, S.S. Solovyev, et al.; OPTIKO- MEKHANICHESKAYA PROMYSHLENNOST, No 12, Dec 85) 93 Aperture Synthesis of...by means of shifting the separate chrominance images and viewing them separately through color glasses with the left and right eyes. Of the pairs of...operation of glass -fiber optical cables and operation of copper-conductor electrical cables is drawn on the basis of that between conduction current in a

The use of sublaminar cables to replace Luque wires.

PubMed

Songer, M N; Spencer, D L; Meyer, P R; Jayaraman, G

1991-08-01

Sublaminar wires have been used in conjunction with posterior instrumentation to stabilize the spine. Sublaminar wiring has fallen into disfavor because of an increase in neurologic complications with the Luque technique as well as wire breakage, dural tears, and difficulty of removal. A cable system consisting of two 49-stranded stainless steel cables connected to one malleable leader was designed to overcome these shortcomings. Biomechanical testing revealed that the maximum yield strength of a single stainless steel cable loop was 2.85-2.94 times greater than a double 0.05-in. stainless steel wire loop. The fatigue tests demonstrated that the stainless steel cables required 6-22 times more cycles to failure than the stainless steel wire. Many of the titanium cables failed immediately under higher loads (0-100 lb) because of slipping of the crimp. The preliminary clinical results after a mean of 19 months of follow-up of 245 cables are encouraging. There has been no breakage or loosening of the cables and no complications associated with the use of the cables. The stainless steel cables are very strong, but more important, the cable flexibility prevents repeated contusions to the spinal cord during insertion of the rods and tightening of wires. The cable conforms to the undersurface of the lamina. This may lead to a decrease in neurologic complications.

Fiber optic accelerometer

NASA Technical Reports Server (NTRS)

August, R. R.

1981-01-01

Low-cost, rugged lightweight accelerometer has been developed that converts mechanical motion into digitized optical outputs and is immune to electromagnetic and electrostatic interferences. Instrument can be placed in hostile environment, such as engine under test, and output led out through miscellany of electrical fields, high temperatures, etc., by optic fiber cables to benign environment of test panel. There, digitized optical signals can be converted to electrical signals for use in standard electrical equipment or used directly in optical devices, such as optical digital computer.

Reliability improvement methods for sapphire fiber temperature sensors

NASA Astrophysics Data System (ADS)

Schietinger, C.; Adams, B.

1991-08-01

Mechanical, optical, electrical, and software design improvements can be brought to bear in the enhancement of fiber-optic sapphire-fiber temperature measurement tool reliability in harsh environments. The optical fiber thermometry (OFT) equipment discussed is used in numerous process industries and generally involves a sapphire sensor, an optical transmission cable, and a microprocessor-based signal analyzer. OFT technology incorporating sensors for corrosive environments, hybrid sensors, and two-wavelength measurements, are discussed.

Next-generation optical wireless communications for data centers

NASA Astrophysics Data System (ADS)

Arnon, Shlomi

2015-01-01

Data centers collect and process information with a capacity that has been increasing from year to year at an almost exponential pace. Traditional fiber/cable data center network interconnections suffer from bandwidth overload, as well as flexibility and scalability issues. Therefore, a technology-shift from the fiber and cable to wireless has already been initiated in order to meet the required data-rate, flexibility and scalability demands for next-generation data center network interconnects. In addition, the shift to wireless reduces the volume allocated to the cabling/fiber and increases the cooling efficiency. Optical wireless communication (OWC), or free space optics (FSO), is one of the most effective wireless technologies that could be used in future data centers and could provide ultra-high capacity, very high cyber security and minimum latency, due to the low index of refraction of air in comparison to fiber technologies. In this paper we review the main concepts and configurations for next generation OWC for data centers. Two families of technologies are reviewed: the first technology regards interconnects between rack units in the same rack and the second technology regards the data center network that connects the server top of rack (TOR) to the switch. A comparison between different network technologies is presented.

Fiber optic cables for transmission of high-power laser pulses in spaceflight applications

NASA Astrophysics Data System (ADS)

Thomes, W. J.; Ott, M. N.; Chuska, R. F.; Switzer, R. C.; Blair, D. E.

2017-11-01

Lasers with high peak power pulses are commonly used in spaceflight missions for a wide range of applications, from LIDAR systems to optical communications. Due to the high optical power needed, the laser has to be located on the exterior of the satellite or coupled through a series of free space optics. This presents challenges for thermal management, radiation resistance, and mechanical design. Future applications will require multiple lasers located close together, which further complicates the design. Coupling the laser energy into a fiber optic cable allows the laser to be relocated to a more favorable position on the spacecraft. Typical fiber optic termination procedures are not sufficient for injection of these high-power laser pulses without catastrophic damage to the fiber endface. In the current study, we will review the causes of fiber damage during high-power injection and discuss our new manufacturing procedures that overcome these issues to permit fiber use with high reliability in these applications. We will also discuss the proper methods for launching the laser pulses into the fiber to avoid damage and how this is being implemented for current spaceflight missions.

Fiber Optic Cables for Transmission of High-Power Laser Pulses in Spaceflight Applications

NASA Technical Reports Server (NTRS)

Thomes, W. J., Jr.; Ott, M. N.; Chuska, R. F.; Switzer, R. C.; Blair, D. E.

2010-01-01

Lasers with high peak power pulses are commonly used in spaceflight missions for a wide range of applications, from LIDAR systems to optical communications. Due to the high optical power needed, the laser has to be located on the exterior of the satellite or coupled through a series of free space optics. This presents challenges for thermal management, radiation resistance, and mechanical design. Future applications will require multiple lasers located close together, which further complicates the design. Coupling the laser energy into a fiber optic cable allows the laser to be relocated to a more favorable position on the spacecraft. Typical fiber optic termination procedures are not sufficient for injection of these high-power laser pulses without catastrophic damage to the fiber endface. In the current study, we will review the causes of fiber damage during high-power injection and discuss our new manufacturing procedures that overcome these issues to permit fiber use with high reliability in these applications. We will also discuss the proper methods for launching the laser pulses into the fiber to avoid damage and how this is being implemented for current spaceflight missions.

The New Age of Telecommunication: Setting the Context for Education.

ERIC Educational Resources Information Center

Wedemeyer, Dan J.

1986-01-01

This overview provides a technological context for the telecommunications age by describing existing and emerging systems--telephone, broadcasting, cable television, fiber optic, satellite, optical disk, and computer technology--and services available via these systems. It is suggested that educators need to become technologically literate and…

Recent developments in photonic networking components for space applications

NASA Astrophysics Data System (ADS)

Parkerson, James P.; Gorman, Lanitia; Thamer, Robert; Chalfant, Charles H.; Hull, Anthony; Orlando, Fred J., Jr.

2003-07-01

Industrial, NASA, and DoD spacecraft designers have recognized the advantages of using fiber optic components and networks for their internal satellite data handling needs. Among the benefits are the total elimination of cable-to-cable and box-to-box EMI; significant size, weight and power reduction; greater on-orbit and integration and test flexibility and significantly lower integration and test costs. Additionally, intra-satellite data rates of 1 to 10 Gbps appear to be an absolute requirement for a number of advanced systems planned for development in the next few years. The only practical way to support these data rates is with fiber optics. Space Photonics and the University of Arkansas have developed fiber optic components (FireFiberTM) and networks that are designed specifically to meet these on-board, high data rate needs using NASA approved materials, packaging processes, and approved radiation tolerant devices. This paper will discuss recent developments in photonic components for spaceborne networks.

Photonic packaging for space applications

NASA Astrophysics Data System (ADS)

Parkerson, James P.; Chalfant, Charles H., III; Orlando, Fred J., Jr.; Hull, Tony

2002-07-01

Industrial, NASA, and DOD spacecraft designers have recognized the advantages of using fiber optic components and networks for their internal satellite data handling needs. Among the benefits are the total elimination of cable-to-cable and box-to-box EMI; significant size, weight and power reduction; greater on-orbit flexibility, simplified integration and test (I&T), and significantly lower I&T costs. Additionally, intra-satellite data rates of 1 to 10 Gbps appear to be an absolute requirement for a number of advanced systems planned for development in the next few years. The only practical way to support these data rates is with fiber optics. Space Photonics and the University of Arkansas have developed fiber optic components (FireFiberTM) and networks that are designed specifically to meet these on-board, high data rate needs using NASA approved materials, packaging processes, and approved radiation tolerant devices. This paper discusses issues relevant to these components and networks.

Method and apparatus for shape and end position determination using an optical fiber

NASA Technical Reports Server (NTRS)

Moore, Jason P. (Inventor)

2010-01-01

A method of determining the shape of an unbound optical fiber includes collecting strain data along a length of the fiber, calculating curvature and bending direction data of the fiber using the strain data, curve-fitting the curvature and bending direction data to derive curvature and bending direction functions, calculating a torsion function using the bending direction function, and determining the 3D shape from the curvature, bending direction, and torsion functions. An apparatus for determining the 3D shape of the fiber includes a fiber optic cable unbound with respect to a protective sleeve, strain sensors positioned along the cable, and a controller in communication with the sensors. The controller has an algorithm for determining a 3D shape and end position of the fiber by calculating a set of curvature and bending direction data, deriving curvature, bending, and torsion functions, and solving Frenet-Serret equations using these functions.

Preliminary analyses of WL experiment No. 701, space environment effects on operating fiber optic systems

NASA Technical Reports Server (NTRS)

Taylor, E. W.; Berry, J. N.; Sanchez, A. D.; Padden, R. J.; Chapman, S. P.

1992-01-01

A brief overview of the analyses performed to date on WL Experiment-701 is presented. Four active digital fiber optic links were directly exposed to the space environment for a period of 2114 days. The links were situated aboard the Long Duration Exposure Facility (LDEF) with the cabled, single fiber windings atop an experimental tray containing instrumentation for exercising the experiment in orbit. Despite the unplanned and prolonged exposure to trapped and galactic radiation, wide temperature extremes, atomic oxygen interactions, and micro-meteorite and debris impacts, in most instances the optical data links performed well within the experimental limits. Analysis of the recorded orbital data clearly indicates that fiber optic applications in space will meet with success. Ongoing tests and analysis of the experiment at the Phillips Laboratory's Optoelectronics Laboratory will expand this premise, and establish the first known and extensive database of active fiber optic link performance during prolonged space exposure. WL Exp-701 was designed as a feasibility demonstration for fiber optic technology in space applications, and to study the performance of operating fiber systems exposed to space environmental factors such as galactic radiation, and wide temperature cycling. WL Exp-701 is widely acknowledged as a benchmark accomplishment that clearly demonstrates, for the first time, that fiber optic technology can be successfully used in a variety of space applications.

A passive optical fibre hydrophone array utilising fibre Bragg grating sensors

NASA Astrophysics Data System (ADS)

Karas, Andrew R.; Papageorgiou, Anthony W.; Cook, Peter R.; Arkwright, John W.

2018-02-01

Many current high performance hydrophones use piezo-electric technology to measure sound pressure in water. These hydrophones are sensitive enough to detect any sound above the lowest ambient ocean acoustic noise, however cost of manufacture, weight and storage volume of the array as well as deployment and maintenance costs can limit their largescale application. Piezo-electric systems also have issues with electro-magnetic interference and the signature of the electrical cabling required in a large array. A fibre optic hydrophone array has advantages over the piezo-electric technology in these areas. This paper presents the operating principle of a passive optical fibre hydrophone array utilising Fibre Bragg Gratings (FBGs). The multiple FBG sensors are interrogated using a single solid state spectrometer which further reduces the cost of the deployed system. A noise equivalent power (NEP) comparison of the developed FBG hydrophone versus an existing piezo-electric hydrophone is presented as well as a comparison to the lowest ambient ocean acoustic noise (sea state zero). This research provides an important first step towards a cost effective multi sensor hydrophone array using FBGs.

Correlation of single mode fiber fabrication factors and radiation response

NASA Astrophysics Data System (ADS)

Friebele, E. J.

1992-02-01

Fiber optic transmission systems, because of their extraordinary channel capacity and decreasing cost, are the preferred terrestrial transmission media of the nation's long distance, inter-city telecommunications infrastructure. Since the commercial telephone network forms the foundation for emergency communication in the event of a national crisis or emergency, additional requirements are placed on the fibers and components of this system. The network must remain operational in the face of such threats as loss of commercial power, disruption by natural causes, violation of physical security, and exposure to the effects of nuclear weapons, including electromagnetic pulse (EMP) and ionizing radiation from the delayed gamma component and fallout. The most stressing environment for the fiber consists of fallout subsequent to a nuclear attack since the long lengths of fiber can be potentially exposed to high total doses. The susceptibility of some types of commercially available fiber optic cable to optical darkening (and hence increased signal loss and bit error rate) from exposure to ionizing radiation raises serious questions about the survivability of such systems in the reconstitution phase of a nuclear conflict.

Bidirectional fiber-wireless and fiber-IVLLC integrated system based on polarization-orthogonal modulation scheme.

PubMed

Lu, Hai-Han; Li, Chung-Yi; Chen, Hwan-Wei; Ho, Chun-Ming; Cheng, Ming-Te; Huang, Sheng-Jhe; Yang, Zih-Yi; Lin, Xin-Yao

2016-07-25

A bidirectional fiber-wireless and fiber-invisible laser light communication (IVLLC) integrated system that employs polarization-orthogonal modulation scheme for hybrid cable television (CATV)/microwave (MW)/millimeter-wave (MMW)/baseband (BB) signal transmission is proposed and demonstrated. To our knowledge, it is the first one that adopts a polarization-orthogonal modulation scheme in a bidirectional fiber-wireless and fiber-IVLLC integrated system with hybrid CATV/MW/MMW/BB signal. For downlink transmission, carrier-to-noise ratio (CNR), composite second-order (CSO), composite triple-beat (CTB), and bit error rate (BER) perform well over 40-km single-mode fiber (SMF) and 10-m RF/50-m optical wireless transport scenarios. For uplink transmission, good BER performance is obtained over 40-km SMF and 50-m optical wireless transport scenario. Such a bidirectional fiber-wireless and fiber-IVLLC integrated system for hybrid CATV/MW/MMW/BB signal transmission will be an attractive alternative for providing broadband integrated services, including CATV, Internet, and telecommunication services. It is shown to be a prominent one to present the advancements for the convergence of fiber backbone and RF/optical wireless feeder.

Cable tester

NASA Astrophysics Data System (ADS)

Rammage, Robert L.

1990-10-01

A device for sequentially testing the plurality of connectors in a wiring harness is disclosed. The harness is attached to the tester by means of adapter cables and a rotary switch is used to sequentially, individually test the connectors by passing a current through the connector. If the connector is unbroken, a light will flash to show it is electrically sound. The adapters allow a large number of cable configurations to be tested using a single tester configuration.

The Reality, Direction, and Future of Computerized Publications.

ERIC Educational Resources Information Center

Levenstein, Nicholas

1994-01-01

Considers potential of personal computers, comparing development of computer today to that of cars in the 1920s. Examines recent changes in communications, university publications, and cultural habits. Explores technological issues, looking at modems and fiber optic cables, better screens, and CD-ROM and optical magnetic drives. (NB)

Honeywell optical investigations on FLASH program

NASA Astrophysics Data System (ADS)

O'Rourke, Ken; Peterson, Eric; Yount, Larry

1995-05-01

The increasing performance and reduction of life cycle cost requirements placed on commercial and military transport aircraft are resulting in more complex, highly integrated aircraft control and management systems. The use of fiber optic data transmission media can make significant contributions in achieving these performance and cost goals. The Honeywell portion of Task 2A on the Fly-by-Light Advanced System Hardware (FLASH) program is evaluating a Primary Flight Control System (PFCS) using pilot and copilot inputs from Active Hand Controllers (AHC) which are optically linked to the primary flight Control Computers (PFCC). Customer involvement is an important element of the Task 2A activity. Establishing customer requirements and perspectives on productization of systems developed under FLASH are key to future product success. The Honeywell elements of the PFCS demonstrator provide a command path that is optically interfaced from crew inputs to commands of distributed, smart actuation subsystems commands. Optical communication architectures are implemented using several protocols including the new AS-1773A 20 Mbps data bus standard. The interconnecting fiber optic cable plant is provided by our Task 1A teammate McDonnell Douglas Aerospace (West). Fiber optic cable plant fabrication uses processed, tools and materials reflecting necessary advances in manufacturing required to make fly-by-light avionics systems marketable.

Robust optical fiber patch-cords for in vivo optogenetic experiments in rats.

PubMed

Trujillo-Pisanty, Ivan; Sanio, Christian; Chaudhri, Nadia; Shizgal, Peter

2015-01-01

In vivo optogenetic experiments commonly employ long lengths of optical fiber to connect the light source (commonly a laser) to the optical fiber implants in the brain. Commercially available patch cords are expensive and break easily. Researchers have developed methods to build these cables in house for in vivo experiments with rodents [1-4]. However, the half-life of those patch cords is greatly reduced when they are used with behaving rats, which are strong enough to break the delicate cable tip and to bite through the optical fiber and furcation tubing. Based on [3] we have strengthened the patch-cord tip that connects to the optical implant, and we have incorporated multiple layers of shielding to produce more robust and resistant cladding. Here, we illustrate how to build these patch cords with FC or M3 connectors. However, the design can be adapted for use with other common optical-fiber connectors. We have saved time and money by using this design in our optical self-stimulation experiments with rats, which are commonly several months long and last four to eleven hours per session. The main advantages are: •Long half-life.•Resistant to moderate rodent bites.•Suitable for long in vivo optogenetic experiments with large rodents.

The "Body Mass Index" of Flexible Ureteroscopes.

PubMed

Proietti, Silvia; Somani, Bhaskar; Sofer, Mario; Pietropaolo, Amelia; Rosso, Marco; Saitta, Giuseppe; Gaboardi, Franco; Traxer, Olivier; Giusti, Guido

2017-10-01

To assess the "body mass index" (BMI) (weight and length) of 12 flexible ureteroscopes (digital and fiber optic) along with the light cables and camera heads, to make the best use of our instruments. Twelve different brand-new flexible ureteroscopes from four different manufacturers, along with eight camera heads and three light cables were evaluated. Each ureteroscope, camera head, and light cable was weighted; the total length of each ureteroscope, shaft, handle, flexible end-tip, and cable were all measured. According to our measurements (in grams [g]), the lightest ureteroscope was the LithoVue (277.5 g), while the heaviest was the URF-V2 (942.5 g). The lightest fiber optic endoscope was the Viper (309 g), while the heaviest was the Cobra (351.5 g). Taking into account the entirety of the endoscopes, the lightest ureteroscope was the Lithovue and the heaviest was the Wolf Cobra with the Wolf camera "3 CHIP HD KAMERA KOPF ENDOCAM LOGIC HD" (1474 g). The longest ureteroscope was the URF-P6 (101.6 cm) and the shortest was the LithoVue (95.5 cm); whereas the Viper and Cobra had the longest shaft (69 cm) and URF-V had the shortest shaft (67.2 cm). The URF-V2 had the longest flexible end-tip (7.6 cm), while the LithoVue had the shortest end-tip (5.7 cm) in both directions (up/down), while the URF-V had the shortest upward deflection (3.7 cm). Newer more versatile digital endoscopes were lighter than their traditional fiber optic counterparts in their entirety, with disposable endoscope having a clear advantage over other reusable ureteroscopes. Knowing the "BMI" of our flexible ureteroscopes is an important information that every endourologist should always take into consideration.

On-board Optical Spectrometry for Detection of Mixture Ratio and Eroded Materials in Rocket Engine Exhaust Plume

NASA Technical Reports Server (NTRS)

Barkhoudarian, Sarkis; Kittinger, Scott

2006-01-01

Optical spectrometry can provide means to characterize rocket engine exhaust plume impurities due to eroded materials, as well as combustion mixture ratio without any interference with plume. Fiberoptic probes and cables were designed, fabricated and installed on Space Shuttle Main Engines (SSME), allowing monitoring of the plume spectra in real time with a Commercial of the Shelf (COTS) fiberoptic spectrometer, located in a test-stand control room. The probes and the cables survived the harsh engine environments for numerous hot-fire tests. When the plume was seeded with a nickel alloy powder, the spectrometer was able to successfully detect all the metallic and OH radical spectra from 300 to 800 nanometers.

The 30/20 GHz communications satellite trunking network study

NASA Technical Reports Server (NTRS)

Kolb, W.

1981-01-01

Alternative transmission media for a CONUS-wide trunking network in the years 1990 and 2000 are examined. The alternative technologies comprised fiber optic cable, conventional C- and Ku-band satellites, and 30/20 GHz satellites. Three levels of implementation were considered - a 10-city network, a 20-city network, and a 40-city network. The cities selected were the major metropolitan areas with the greatest communications demand. All intercity voice, data, and video traffic carried more than 40 miles was included in the analysis. In the optimized network, traffic transmitted less than 500 miles was found to be better served by fiber optic cable in 1990. By the year 2000, the crossover point would be down to 200 miles, assuming availability of 30/20 GHz satellites.

Expeditionary Lighting Systems for Military Shelters

DTIC Science & Technology

2009-11-04

Lumiled LED Housing Nonimaging Beamformer Heat Sink Connector Retractable Cable O Transportation Configuration Physical Optics Corporation (POC) LED...New Lighting Technologies: • Technology: Light Emitting Diode (LED) o Physical Optics Corp [SBIR] o Techshot [SBIR] [Congressional Effort o Jameson LED...rugged and durable—no lamp to damage or replace • Custom designed optical diffuser prevents glare and “eye spots” • Operates on universal voltage, 90

A search for applications of Fiber Optics in early warning systems for natural hazards.

NASA Astrophysics Data System (ADS)

Wenker, Koen; Bogaard, Thom

2013-04-01

In order to reduce the societal risk associated with natural hazards novel technologies could help to advance in early warning systems. In our study we evaluate the use of multi-sensor technologies as possible early-warning systems for landslides and man-made structures, and the integration of the information in a simple Decision Support System (DSS). In this project, particular attention will be paid to some new possibilities available in the field of distributed monitoring systems of relevant parameters for landslide and man-made structures monitoring (such as large dams and bridges), and among them the distributed monitoring of temperature, strain and acoustic signals by FO cables. Fiber Optic measurements are becoming more and more popular. Fiber optic cables have been developed in the telecommunication business to send large amounts of information over large distances with the speed of light. Because of the commercial application, production costs are relatively low. Using fiber optics for measurements has several advantages. This novel technology is, for instance, immune to electromagnetic interference, appears stable, very accurate, and has the potential to measure several independent physical properties in a distributed manner. The high resolution spatial and temporal distributed information on e.g. temperature or strain (or both) make fiber optics an interesting measurement technique. Several applications have been developed in both engineering as science and the possibilities seem numerous. We will present a thorough literature review that was done to assess the applicability and limitations of FO cable technology. This review was focused but not limited to application in landslide research. Several examples of current practices will be shown, also from outside the natural hazard practice and possible application will be discussed.

Dynamics of a passive micro-vibration isolator based on a pretensioned plane cable net structure and fluid damper

NASA Astrophysics Data System (ADS)

Chen, Yanhao; Lu, Qi; Jing, Bo; Zhang, Zhiyi

2016-09-01

This paper addresses dynamic modelling and experiments on a passive vibration isolator for application in the space environment. The isolator is composed of a pretensioned plane cable net structure and a fluid damper in parallel. Firstly, the frequency response function (FRF) of a single cable is analysed according to the string theory, and the FRF synthesis method is adopted to establish a dynamic model of the plane cable net structure. Secondly, the equivalent damping coefficient of the fluid damper is analysed. Thirdly, experiments are carried out to compare the plane cable net structure, the fluid damper and the vibration isolator formed by the net and the damper, respectively. It is shown that the plane cable net structure can achieve substantial vibration attenuation but has a great amplification at its resonance frequency due to the light damping of cables. The damping effect of fluid damper is acceptable without taking the poor carrying capacity into consideration. Compared to the plane cable net structure and the fluid damper, the isolator has an acceptable resonance amplification as well as vibration attenuation.

Multipoint Pressure and Temperature Sensing Fiber Optic Cable for Monitoring CO 2 Sequestration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Challener, William

2015-02-10

This report describes the work completed on contract DE-FE0010116. The goal of this two year project was to develop and demonstrate in the laboratory a highly accurate multi-point pressure measurement fiber optic cable based on MEMS pressure sensors suitable for downhole deployment in a CO 2 sequestration well. The sensor interrogator was also to be demonstrated in a remote monitoring system and environmental testing was to be completed to indicate its downhole survivability over a lengthy period of time (e.g., 20 years). An interrogator system based on a pulsed laser excitation was shown to be capable of multiple (potentially 100+)more » simultaneous sensor measurements. Two sensors packages were completed and spliced in a cable onto the same fiber and measured. One sensor package was subsequently measured at high temperatures and pressures in supercritical CO 2, while the other package was measured prior and after being subjected to high torque stresses to mimic downhole deployment. The environmental and stress tests indicated areas in which the package design should be further improved.« less

30 CFR 75.601-3 - Short circuit protection; dual element fuses; current ratings; maximum values.

Code of Federal Regulations, 2011 CFR

2011-07-01

... devices shall not exceed the maximum values specified in this section: Conductor size (AWG or MGM) Single conductor cable Ampacity Max. fuse rating Two conductor cable Ampacity Max. fuse rating 14 15 15 12 20 20 10...

Shielding effectiveness of multiple-shield cables with arbitrary terminations via transmission line analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campione, Salvatore; Basilio, Lorena I.; Warne, Larry Kevin

Our paper reports on a transmission-line model for calculating the shielding effectiveness of multiple-shield cables with arbitrary terminations. Since the shields are not perfect conductors and apertures in the shields permit external magnetic and electric fields to penetrate into the interior regions of the cable, we use this model to estimate the effects of the outer shield current and voltage (associated with the external excitation and boundary conditions associated with the external conductor) on the inner conductor current and voltage. It is commonly believed that increasing the number of shields of a cable will improve the shielding performance. But thismore » is not always the case, and a cable with multiple shields may perform similar to or worse than a cable with a single shield. Furthermore, we want to shed more light on these situations, which represent the main focus of this paper.« less

Shielding effectiveness of multiple-shield cables with arbitrary terminations via transmission line analysis

DOE PAGES

Campione, Salvatore; Basilio, Lorena I.; Warne, Larry Kevin; ...

2016-06-25

Our paper reports on a transmission-line model for calculating the shielding effectiveness of multiple-shield cables with arbitrary terminations. Since the shields are not perfect conductors and apertures in the shields permit external magnetic and electric fields to penetrate into the interior regions of the cable, we use this model to estimate the effects of the outer shield current and voltage (associated with the external excitation and boundary conditions associated with the external conductor) on the inner conductor current and voltage. It is commonly believed that increasing the number of shields of a cable will improve the shielding performance. But thismore » is not always the case, and a cable with multiple shields may perform similar to or worse than a cable with a single shield. Furthermore, we want to shed more light on these situations, which represent the main focus of this paper.« less

Analysis of Harmonic Vibration of Cable-Stayed Footbridge under the Influence of Changes of the Cables Tension

NASA Astrophysics Data System (ADS)

Pakos, Wojciech

2015-09-01

The paper presents numerical analysis of harmonically excited vibration of a cable-stayed footbridge caused by a load function simulating crouching (squats) while changing the static tension in chosen cables. The intentional synchronized motion (e.g., squats) of a single person or group of persons on the footbridge with a frequency close to the natural frequency of the structure may lead to the resonant vibrations with large amplitudes. The appropriate tension changes in some cables cause detuning of resonance on account of stiffness changes of structures and hence detuning in the natural frequency that is close to the excitation frequency. The research was carried out on a 3D computer model of a real structure - a cable-stayed steel footbridge in Leśnica, a quarter of Wrocław, Poland, with the help of standard computer software based on FEM COSMOS/M System.

The management of large cabling campaigns during the Long Shutdown 1 of LHC

NASA Astrophysics Data System (ADS)

Meroli, S.; Machado, S.; Formenti, F.; Frans, M.; Guillaume, J. C.; Ricci, D.

2014-03-01

The Large Hadron Collider at CERN entered into its first 18 month-long shutdown period in February 2013. During this period the entire CERN accelerator complex will undergo major consolidation and upgrade works, preparing the machines for LHC operation at nominal energy (7 TeV/beam). One of the most challenging activities concerns the cabling infrastructure (copper and optical fibre cables) serving the CERN data acquisition, networking and control systems. About 1000 kilometres of cables, distributed in different machine areas, will be installed, representing an investment of about 15 MCHF. This implies an extraordinary challenge in terms of project management, including resource and activity planning, work execution and quality control. The preparation phase of this project started well before its implementation, by defining technical solutions and setting financial plans for staff recruitment and material supply. Enhanced task coordination was further implemented by deploying selected competences to form a central support team.

Intra-building telecommunications cabling standards for Sandia National Laboratories, New Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adams, R.L.

1993-08-01

This document establishes a working standard for all telecommunications cable installations at Sandia National Laboratories, New Mexico. It is based on recent national commercial cabling standards. The topics addressed are Secure and Open/Restricted Access telecommunications environments and both twisted-pair and optical-fiber components of communications media. Some of the state-of-the-art technologies that will be supported by the intrabuilding cable infrastructure are Circuit and Packet Switched Networks (PBX/5ESS Voice and Low-Speed Data), Local Area Networks (Ethernet, Token Ring, Fiber and Copper Distributed Data Interface), and Wide Area Networks (Asynchronous Transfer Mode). These technologies can be delivered to every desk and can transportmore » data at rates sufficient to support all existing applications (such as Voice, Text and graphics, Still Images, Full-motion Video), as well as applications to be defined in the future.« less

Preliminary fabrication and characterization of low-leakage hybrid coaxial cable

NASA Astrophysics Data System (ADS)

Rudnitsky, Arkady; Elbaz, David; Zalevsky, Zeev

2013-10-01

In this paper we present the fabrication and the initial characterization of a new type of coaxial cable having reduced leakage characteristics and the capability of transmitting optical signals, in additional to the RF signal, through the glass medium between the metallic conductors. The suggested decreased leakage and material loss is obtained by using different metallic shield geometry. The suggested model is composed of a central conductor surrounded by plurality of metallic wires circularly disposed.

1. Credit PSR. View looks north from aircraft apron at ...

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

1. Credit PSR. View looks north from aircraft apron at south and east facades of the first hangar built at North Base in 1942. Note Building 4306 attached to hangar in distance; this structure is the boiler house to heat hangar during winters. Cable reels in foreground are from fiber optic and electrical cable installations ongoing at Edwards Air Force Base. - Edwards Air Force Base, North Base, Unicon Portable Hangar, First & C Streets, Boron, Kern County, CA

Proceedings of the International Wire and Cable Symposium (38th) Held in Atlanta, Georgia on November 14-16, 1989

DTIC Science & Technology

1989-11-01

Park/Atlanta Nnicross, GA 30092 (404) 448-2206 ADVISORY GROUP Leo Chattier Marta Farago DCM Industries, Inc. Northern Telecom Canada Ltd. 13666 East...CABLE DESIGNIAPPLICATIONS-f ( Future Optical Networks-S. PA. James. 0. A. Caalrporson. Mr. Leo Chattler. 0CM Industries. Inc. Ferguson, D. Drovet...DESIGNIAPPLICATIONS 11 SESSION XI: POSTER SESSION Chairperson: Mr. Leo Chattier. DCM Industries. Chairperson: Mr. Peter Stahl. General Electric Company. San

Characterization of a fiber-less, multichannel optical probe for continuous wave functional near-infrared spectroscopy based on silicon photomultipliers detectors: in-vivo assessment of primary sensorimotor response.

PubMed

Chiarelli, Antonio M; Libertino, Sebania; Zappasodi, Filippo; Mazzillo, Massimo; Pompeo, Francesco Di; Merla, Arcangelo; Lombardo, Salvatore; Fallica, Giorgio

2017-07-01

We report development, testing, and in vivo characterization of a multichannel optical probe for continuous wave (CW) functional near-infrared spectroscopy (fNIRS) that relies on silicon photomultipliers (SiPMs) detectors. SiPMs are cheap, low voltage, and robust semiconductor light detectors with performances analogous to photomultiplier tubes (PMTs). In contrast with PMTs, SiPMs allow direct contact with the head and transfer of the analog signals through thin cables greatly increasing the system flexibility avoiding optical fibers. The coupling of SiPMs and light-emitting diodes (LEDs) made the optical probe lightweight and robust against motion artifacts. After characterization of SiPM performances, which was proven to provide a noise equivalent power below 3 fW, the apparatus was compared through an in vivo experiment to a commercial system relying on laser diodes, PMTs, and optical fibers for light probing and detection. The optical probes were located over the primary sensorimotor cortex and the similarities between the hemodynamic responses to the contralateral motor task were assessed. When compared to other state-of-the-art wearable fNIRS systems, where photodiode detectors are employed, the single photon sensitivity and dynamic range of SiPMs can fully exploit the long and variable interoptode distances needed for correct estimation of brain hemodynamics using CW-fNIRS.

High-speed, bi-directional dual-core fiber transmission system for high-density, short-reach optical interconnects

NASA Astrophysics Data System (ADS)

Geng, Ying; Li, Shenping; Li, Ming-Jun; Sutton, Clifford G.; McCollum, Robert L.; McClure, Randy L.; Koklyushkin, Alexander V.; Matthews, Karen I.; Luther, James P.; Butler, Douglas L.

2015-03-01

A complete single mode dual-core fiber system for short-reach optical interconnects is fabricated and tested for high-speed data transmission. It includes dual-core fibers capable of bi-directional data transmission, dual-core simplex LC connectors, and fan-outs. The transmission system offers simplified bi-directional traffic engineering with integrated bidirectional transceivers and compact system design, utilizing simplex dual-core LC connectors that use half the space while increasing the bandwidth density by a factor of two. The fiber has two cores that are compatible with single mode fiber and conforms to the industry standard outer diameter of 125 μm. This reduces operational complexity by reducing the size and number of fibers, cables and connectors. Measured OTDR loss for both cores was 0.34 dB/km at 1310 nm and 0.19 dB/km at 1550 nm. Crosstalk for a piece of 5.8 km long dual-core fiber was measured to be below -75 dB at 1310 nm, and below -40 dB at 1550 nm. Both free-space optics fan-outs and tapered-fiber-coupler based MCF fan-outs were evaluated for the transmission system. Error-free and penalty-free 25 Gb/s bi-directional transmission performance was demonstrated for three different fiber lengths, 200 m, 2 km and 10 km, using the complete all-fiber-based system including connectors and fan-outs. This single mode, dual-core fiber transmission system adds complementary value to systems where additional increases in bandwidth density can come from wavelength division multiplexing and multiple bits per symbol.

Emerging Subsea Networks: SMART Cable Systems for Science and Society

NASA Astrophysics Data System (ADS)

Howe, B. M.; Butler, R.; Joint Task Force, U.

2016-02-01

The subsea telecommunications cable industry is approaching a prospective new era: deploying SMART subsea cable systems (SMART = Science Monitoring And Reliable Telecommunication). The current global, commercial cable infrastructure consists of 1 Gm of cable, being refreshed now and expanding in the future. The SMART concept is to add a small external sensor package along the cable system at its optical repeaters to transmit important real-time environmental data via a dedicated wavelength or overhead channel in the transmission system, avoiding any impact on the commercial traffic. These small, reliable, existing sensors would precisely measure temperature, pressure and three-axis acceleration across the world's ocean floor over an extended period of time, being deployed using standard cable-laying procedures on new or refurbished cables, but not requiring maintenance through the 2-3 decade life of the cable systems. The game-changing factor is the urgent international need for ocean environmental data related to mitigating climate and sea-level change and improving tsunami and slope failure hazard warnings. Societal costs incurred by these are reaching billions of dollars and hundreds of thousands of deaths. Pressures for new and urgent public policies are evident from the 5th IPCC Assessment, USA-China agreement on limiting greenhouse gas emissions, clear evidence for rapid global warming, 21st Session of the Conference of the Parties to the UNFCCC (December 2015, Paris), and the scale of the costs of inaction. To support revised public policies and actions, decision-makers, industry leaders, and the public are seeking key scientific data, which will necessitate new sources of funding. Hence, the emergence of new SMART cable systems offered by the subsea telecommunications industry will provide new market opportunities, engage additional non-traditional users, and make profound societal contributions. The Joint Task Force (JTF) on SMART Subsea Cable Systems established by three UN agencies (ITU, WMO, and UNESCO IOC) is helping facilitate this transformation. http://www.itu.int/en/ITU-T/climatechange/task-force-sc/Pages/default.aspx or google 'jtf cable'

Planning Communication Networks to Deliver Educational Services.

ERIC Educational Resources Information Center

Ballard, Richard J.; Eastwood, Lester F., Jr.

As companion to the more general document Telecommunications Media for the Delivery of Educational Programming , this report concentrates on the technical and economic factors affecting the design of only one class of educational networks, dedicated coaxial cable systems. To provide illustrations, possible single and dual dedicated cable networks…

Kansas Communication and Instruction System through Fiber-Optic Transmission.

ERIC Educational Resources Information Center

Kansas State Dept. of Education, Topeka.

Schools and communities will restructure as they move into the next decade. The success of this restructuring will be dependent upon access to and sharing of quality teaching and information through an expanded communication system. One of the major two-way interactive technologies is the fiber-optic cable: a delivery system that will provide…

Laser peening with fiber optic delivery

DOEpatents

Friedman, Herbert W.; Ault, Earl R.; Scheibner, Karl F.

2004-11-16

A system for processing a workpiece using a laser. The laser produces at least one laser pulse. A laser processing unit is used to process the workpiece using the at least one laser pulse. A fiber optic cable is used for transmitting the at least one laser pulse from the laser to the laser processing unit.

FOREX-A Fiber Optics Diagnostic System For Study Of Materials At High Temperatures And Pressures

NASA Astrophysics Data System (ADS)

Smith, D. E.; Roeske, F.

1983-03-01

We have successfully fielded a Fiber Optics Radiation EXperiment system (FOREX) designed for measuring material properties at high temperatures and pressures on an underground nuclear test. The system collects light from radiating materials and transmits it through several hundred meters of optical fibers to a recording station consisting of a streak camera with film readout. The use of fiber optics provides a faster time response than can presently be obtained with equalized coaxial cables over comparable distances. Fibers also have significant cost and physical size advantages over coax cables. The streak camera achieves a much higher information density than an equivalent oscilloscope system, and it also serves as the light detector. The result is a wide bandwidth high capacity system that can be fielded at a relatively low cost in manpower, space, and materials. For this experiment, the streak camera had a 120 ns time window with a 1.2 ns time resolution. Dynamic range for the system was about 1000. Beam current statistical limitations were approximately 8% for a 0.3 ns wide data point at one decade above the threshold recording intensity.

Portable coastal observatories

USGS Publications Warehouse

Frye, Daniel; Butman, Bradford; Johnson, Mark; von der Heydt, Keith; Lerner, Steven

2000-01-01

Ocean observational science is in the midst of a paradigm shift from an expeditionary science centered on short research cruises and deployments of internally recording instruments to a sustained observational science where the ocean is monitored on a regular basis, much the way the atmosphere is monitored. While satellite remote sensing is one key way of meeting the challenge of real-time monitoring of large ocean regions, new technologies are required for in situ observations to measure conditions below the ocean surface and to measure ocean characteristics not observable from space. One method of making sustained observations in the coastal ocean is to install a fiber optic cable from shore to the area of interest. This approach has the advantage of providing power to offshore instruments and essentially unlimited bandwidth for data. The LEO-15 observatory offshore of New Jersey (yon Alt et al., 1997) and the planned Katama observatory offshore of Martha's Vineyard (Edson et al., 2000) use this approach. These sites, along with other cabled sites, will play an important role in coastal ocean science in the next decade. Cabled observatories, however, have two drawbacks that limit the number of sites that are likely to be installed. First, the cable and the cable installation are expensive and the shore station needed at the cable terminus is often in an environmentally sensitive area where competing interests must be resolved. Second, cabled sites are inherently limited geographically to sites within reach of the cable, so it is difficult to cover large areas of the coastal ocean.

Fiber Pulling Apparatus

NASA Technical Reports Server (NTRS)

Workman, Gary L.; Smith, Guy A.; OBrien, Sue; Adcock, Leonard

1998-01-01

The fiber optics industry has grown into a multi-billion marketplace that will continue to grow into the 21st century. Optical fiber communications is currently dominated by silica glass technology. Successful efforts to improve upon the low loss transmission characteristics of silica fibers have propelled the technology into the forefront of the communications industry. However, reaching the theoretical transmission capability of silica fiber through improved processing has still left a few application areas in which other fiber systems can provide an influential role due to specific characteristics of high theoretical transmission in the 2 - 3 micron wavelength region. One of the other major materials used for optical fibers is the systems based upon Heavy Metal Fluoride Glass (HMFG). Commercial interest is driven primarily by the potential for low loss repeaterless infrared fibers. An example of the major communications marketplace which would benefit from the long distance repeaterless capability of infrared fibers is the submarine cables which link the continents. When considering commercial interests, optical fiber systems provide a healthy industrial position which continues to expand. Major investments in the systems used for optical fiber communications have continued to increase each year and are predicted to continue well into the next century. Estimates of 8.5% compounded annually are predicted through 1999 for the North American market and 1 1 % worldwide. The growth for the optical fiber cable itself is expected to continue between 44 and 50 per cent of the optical fiber communications budget through 1999. The total budget in 1999 world-wide is expected to be in the neighborhood of $9 billion. Another survey predicts that long haul telecommunications represents 15% of a world-wide fiber optics market in 1998. The actual amount allotted to cable was not specified. However, another market research had predicted that the cable costs alone represents more than 50% of the total budget each year through 1998. A newly emerging activity is the commercial development of doped optical fibers which can be pumped by laser diodes to provide amplification of the communication signals. This technology is newly emerging and will be developed for commercial interests in the United States by Galileo Electro-optical Incorporated in Sturbridge, MA on a license from British Telecom. Long repeaterless communication links provide the biggest stimulus for this technology. As an example of the of the revenues involved in the optical fiber communications 3 industry, the current trade journal lists that for the fiscal years, 1991 - 1994, 185 separate undersea links were established. In addition, another 105 links are planned through 1998. The distribution of revenues involved in the undersea installations is roughly $8.5 billion through 1993 and another $13 billion planned through 1998. A large portion of the future activity (34%) is planned for Southeast Asia and the Pacific Region. Other examples of the commercial utility of optical fiber networks is given in a recent scientific symposium in which the outlook for HMFG infrared fiber was determined to be very bright.Another area of interest lies in the use of fiber optics for laser surgery delivery systems.

Operating experience of the southwire high-temperature superconducting cable project

NASA Astrophysics Data System (ADS)

Hughey, R. L.; Lindsay, D.

2002-01-01

Southwire Company of Carrollton, Georgia in cooperation with Oak Ridge National Laboratory has designed, built, installed and is operating the world's first field installation of a High Temperature Superconducting (HTS) cable system. The cables supply power to three Southwire manufacturing facilities and part of the corporate headquarters building in Carrollton, GA. The system consists of three 30-m single phase cables rated at 12.4 kV, 1250 Amps, liquid nitrogen cooling system, and the computer-based control system. The cables are built using BSCCO-2223 powder-in-tube HTS tapes and a proprietary cryogenic dielectric material called Cryoflex™. The cables are fully shielded with a second layer of HTS tapes to eliminate any external magnetic fields. The Southwire HTS cables were first energized on january 6, 2000. Since that time they have logged over 8,500 hours of operation while supplying 100% of the required customer load. To date, the cables have worked without failure and operations are continuing. The cable design has passed requisite testing for this class of conventional cables including 10× over current to 12,500 Amps and BIL testing to 110 kV. Southwire has also successfully designed and tested a cable splice. System heat loads and AC Losses have been measured and compared to calculated values. On June 1, 2001 on-site monitoring was ceased and the system was changed to unattended operation to further prove the reliability of the HTS cable system. .

Fiberoptic characteristics for extreme operating environments

NASA Technical Reports Server (NTRS)

Delcher, R. C.

1992-01-01

Fiberoptics could offer several major benefits for cryogenic liquid-fueled rocket engines, including lightning immunity, weight reduction, and the possibility of implementing a number of new measurements for engine condition monitoring. The technical feasibility of using fiberoptics in the severe environments posed by cryogenic liquid-fueled rocket engines was determined. The issues of importance and subsequent requirements for this use of fiberoptics were compiled. These included temperature ranges, moisture embrittlement succeptability, and the ability to withstand extreme shock and vibration levels. Different types of optical fibers were evaluated and several types of optical fibers' ability to withstand use in cryogenic liquid-fueled rocket engines was demonstrated through environmental testing of samples. This testing included: cold-bend testing, moisture embrittlement testing, temperature cycling, temperature extremes testing, vibration testing, and shock testing. Three of five fiber samples withstood the tests to a level proving feasibility, and two of these remained intact in all six of the tests. A fiberoptic bundle was also tested, and completed testing without breakage. Preliminary cabling and harnessing for fiber protection was also demonstrated. According to cable manufacturers, the successful -300 F cold bend, vibration, and shock tests are the first instance of any major fiberoptic cable testing below roughly -55 F. This program has demonstrated the basic technical feasibility of implementing optical fibers on cryogenic liquid-fueled rocket engines, and a development plan is included highlighting requirements and issues for such an implementation.

Fibre cables in the lacunae of Typha leaves contribute to a tensegrity structure.

PubMed

Witztum, Allan; Wayne, Randy

2014-04-01

Cables composed of long, non-lignified fibre cells enclosed in a cover of much shorter thin-walled, crystal-containing cells traverse the air chambers (lacunae) in leaves of the taller species of Typha. The non-lignified fibre cables are anchored in diaphragms composed of stellate cells of aerenchyma tissue that segment the long air chambers into smaller compartments. Although the fibre cables are easily observed and can be pulled free from the porous-to-air diaphragms, their structure and function have been ignored or misinterpreted. Leaves of various species of Typha were dissected and fibre cables were pulled free and observed with a microscope using bright-field and polarizing optics. Maximal tensile strength of freshly removed cables was measured by hanging weights from fibre cables, and Instron analysis was used to produce curves of load versus extension until cables broke. Polarized light microscopy revealed that the cellulose microfibrils that make up the walls of the cable fibres are oriented parallel to the long axis of the fibres. This orientation ensures that the fibre cables are mechanically stiff and strong under tension. Accordingly, the measured stiffness and tensile strength of the fibre cables were in the gigapascal range. In combination with the dorsal and ventral leaf surfaces and partitions that contain lignified fibre bundles and vascular strands that are strong in compression, the very fine fibre cables that are strong under tension form a tensegrity structure. The tensegrity structure creates multiple load paths through which stresses are redistributed throughout the 1-3 m tall upright leaves of Typha angustifolia, T. latifolia, T. × glauca, T. domingensis and T. shuttleworthii. The length of the fibre cables relative to the length of the leaf blades is reduced in the last-formed leaves of flowering individuals. Fibre cables are absent in the shorter leaves of Typha minima and, if present, only extend for a few centimetres from the sheath into the leaf blade of Typha laxmannii. The advantage of the structure of the Typha leaf blade, which enables stiffness to give way to flexibility under windy conditions, is discussed for both vegetative and flowering plants.

Fibre cables in the lacunae of Typha leaves contribute to a tensegrity structure

PubMed Central

Witztum, Allan; Wayne, Randy

2014-01-01

Background and Aims Cables composed of long, non-lignified fibre cells enclosed in a cover of much shorter thin-walled, crystal-containing cells traverse the air chambers (lacunae) in leaves of the taller species of Typha. The non-lignified fibre cables are anchored in diaphragms composed of stellate cells of aerenchyma tissue that segment the long air chambers into smaller compartments. Although the fibre cables are easily observed and can be pulled free from the porous-to-air diaphragms, their structure and function have been ignored or misinterpreted. Methods Leaves of various species of Typha were dissected and fibre cables were pulled free and observed with a microscope using bright-field and polarizing optics. Maximal tensile strength of freshly removed cables was measured by hanging weights from fibre cables, and Instron analysis was used to produce curves of load versus extension until cables broke. Key Results and Conclusions Polarized light microscopy revealed that the cellulose microfibrils that make up the walls of the cable fibres are oriented parallel to the long axis of the fibres. This orientation ensures that the fibre cables are mechanically stiff and strong under tension. Accordingly, the measured stiffness and tensile strength of the fibre cables were in the gigapascal range. In combination with the dorsal and ventral leaf surfaces and partitions that contain lignified fibre bundles and vascular strands that are strong in compression, the very fine fibre cables that are strong under tension form a tensegrity structure. The tensegrity structure creates multiple load paths through which stresses are redistributed throughout the 1–3 m tall upright leaves of Typha angustifolia, T. latifolia, T. × glauca, T. domingensis and T. shuttleworthii. The length of the fibre cables relative to the length of the leaf blades is reduced in the last-formed leaves of flowering individuals. Fibre cables are absent in the shorter leaves of Typha minima and, if present, only extend for a few centimetres from the sheath into the leaf blade of Typha laxmannii. The advantage of the structure of the Typha leaf blade, which enables stiffness to give way to flexibility under windy conditions, is discussed for both vegetative and flowering plants. PMID:24532647

VCSEL-based optical transceiver module for high-speed short-reach interconnect

NASA Astrophysics Data System (ADS)

Yagisawa, Takatoshi; Oku, Hideki; Mori, Tatsuhiro; Tsudome, Rie; Tanaka, Kazuhiro; Daikuhara, Osamu; Komiyama, Takeshi; Ide, Satoshi

2017-02-01

Interconnects have been more important in high-performance computing systems and high-end servers beside its improvements in computing capability. Recently, active optical cables (AOCs) have started being used for this purpose instead of conventionally used copper cables. The AOC enables to extend the transmission distance of the high-speed signals dramatically by its broadband characteristics, however, it tend to increase the cost. In this paper, we report our developed quad small form-factor pluggable (QSFP) AOC utilizing cost-effective optical-module technologies. These are a unique structure using generally used flexible printed circuit (FPC) in combination with an optical waveguide that enables low-cost high-precision assembly with passive alignment, a lens-integrated ferrule that improves productivity by eliminating a polishing process for physical contact of standard PMT connector for the optical waveguide, and an overdrive technology that enables 100 Gb/s (25 Gb/s × 4-channel) operation with low-cost 14 Gb/s vertical-cavity surfaceemitting laser (VCSEL) array. The QSFP AOC demonstrated clear eye opening and error-free operation at 100 Gb/s with high yield rate even though the 14 Gb/s VCSEL was used thanks to the low-coupling loss resulting from the highprecision alignment of optical devices and the over-drive technology.

The Cabled Component of NSF's Ocean Observatories Initiative: A Distributed, Multi-Sensor, Interactive Telepresence Within Ever-Shifting Marine Ecosystems

NASA Astrophysics Data System (ADS)

Delaney, J. R.; Kelley, D. S.; Proskurowski, G. K.; Kawka, O. E.; Fundis, A.; Mulvihill, M.; Harkins, G.; Harrington, M.; McGuire, C.; Manalang, D.; Light, R.; Stewart, A.; Brand, B.

2013-12-01

Since mid-year 2011, NSF's Ocean Observatories Initiative has made considerable progress in installing its cabled seafloor and water-column component off the Washington-Oregon Coast. The Primary Infrastructure is nearly operational and includes ~900 km of high-power (10 kV) and bandwidth (10 Gbs) submarine electro-optical cable and 7 seafloor power- and communications switching stations (nodes) in a two-cable network spanning tectonically active zones across the Juan de Fuca Plate, with access to the overlying ocean. The system is connected to a shore-landing in Pacific City, Oregon, with a dual-path terrestrial backhaul to Portland where connections to major continent-wide, high-speed networks link via the Internet to the undersea system. During summer 2013 the VISIONS'13 expedition, using the R/V Thompson and the remotely operated vehicle (ROV) ROPOS, placed a number of secondary infrastructure elements on the seafloor, ready to be connected to the Primary Nodes when the system is fully tested and accepted by the Consortium for Ocean Leadership. Secondary infrastructure installed using the ROV ROPOS includes over 23,000 meters of extension cables, which comprise twelve electro-optical and electrical cables that provide links from the Primary Nodes to experimental sites and instrument clusters. Smaller nodes (junction boxes) were also deployed, with three installed on the seafloor. All cables and junction boxes were fully tested, which included powering up and communicating through the nodes and sensors using the ROV ROPOS as a power-communication source, and live data transmission of the resultant engineering and science data to the ship located 3000-1500m above the seafloor. Locations include sites near the base of the continental slope and on Axial Seamount, the most magmatically active volcano on the Juan de Fuca Ridge. Real-time data streamed from instruments connected to extension cables at Axial Volcano via ROPOS revealed a significant local earthquake on the volcano, and a minor signal showing direct tidal measurements from 300 miles offshore. Sensors to be installed and connected in 2014 will provide seismic information, current velocities, inflation and deflation measurements of the volcanic caldera, high-definition video on demand, digital-still imagery, chemical data from methane seeps and vent sites using mass spectrometers, and an array of thermistors in a low-temperature vent field. Six instrumented full water-column moorings with two different types of profilers will be installed and connected to the cable in 2014.

29 CFR 1910.305 - Wiring methods, components, and equipment for general use.

Code of Federal Regulations, 2010 CFR

2010-07-01

... distribution center. (B) Conductors shall be run as multiconductor cord or cable assemblies. However, if... persons, feeders may be run as single insulated conductors. (v) The following requirements apply to branch... shall be multiconductor cord or cable assemblies or open conductors. If run as open conductors, they...

29 CFR 1910.305 - Wiring methods, components, and equipment for general use.

Code of Federal Regulations, 2011 CFR

2011-07-01

... distribution center. (B) Conductors shall be run as multiconductor cord or cable assemblies. However, if... persons, feeders may be run as single insulated conductors. (v) The following requirements apply to branch... shall be multiconductor cord or cable assemblies or open conductors. If run as open conductors, they...

29 CFR 1910.305 - Wiring methods, components, and equipment for general use.

Code of Federal Regulations, 2013 CFR

2013-07-01

... distribution center. (B) Conductors shall be run as multiconductor cord or cable assemblies. However, if... persons, feeders may be run as single insulated conductors. (v) The following requirements apply to branch... shall be multiconductor cord or cable assemblies or open conductors. If run as open conductors, they...

29 CFR 1910.305 - Wiring methods, components, and equipment for general use.

Code of Federal Regulations, 2014 CFR

2014-07-01

... distribution center. (B) Conductors shall be run as multiconductor cord or cable assemblies. However, if... persons, feeders may be run as single insulated conductors. (v) The following requirements apply to branch... shall be multiconductor cord or cable assemblies or open conductors. If run as open conductors, they...

29 CFR 1910.305 - Wiring methods, components, and equipment for general use.

Code of Federal Regulations, 2012 CFR

2012-07-01

... distribution center. (B) Conductors shall be run as multiconductor cord or cable assemblies. However, if... persons, feeders may be run as single insulated conductors. (v) The following requirements apply to branch... shall be multiconductor cord or cable assemblies or open conductors. If run as open conductors, they...

Proceedings of the IWCS (International Wire and Cable Symposium (39th) Held in Reno, Nevada on 13-15 Nov 1990

DTIC Science & Technology

1990-11-15

degradation or magneto Fo -longer length (L) 1the survival probabilty is hydrodynamic effect. The polymeric materials may also outgas dissolved hydrogen or...pressure tube, together with the methcd of will outgas up to 8cc(H 2)/km. This gives an waterblocking the tube bore, will be identical increase in optical...lines Relative humidity: up to 100% (@ 350 C) not exceeding 200 km. These cables traditionally consist of quads with Second-generation long-distance

Interface For Fault-Tolerant Control System

NASA Technical Reports Server (NTRS)

Shaver, Charles; Williamson, Michael

1989-01-01

Interface unit and controller emulator developed for research on electronic helicopter-flight-control systems equipped with artificial intelligence. Interface unit interrupt-driven system designed to link microprocessor-based, quadruply-redundant, asynchronous, ultra-reliable, fault-tolerant control system (controller) with electronic servocontrol unit that controls set of hydraulic actuators. Receives digital feedforward messages from, and transmits digital feedback messages to, controller through differential signal lines or fiber-optic cables (thus far only differential signal lines have been used). Analog signals transmitted to and from servocontrol unit via coaxial cables.

Fine Scale Baleen Whale Behavior Observed Via Tagging Over Daily Time Scales

DTIC Science & Technology

2014-09-30

During late fall 2013 and winter 2014, I built a data logger for the optical plankton counter ( OPC ) to facilitate its continued use on the NOAA Ship...Gordon Gunter. This ship has very long (> 5 km) of conducting sea cable, and we had communication issues with the OPC with the manufacturers...telemetry system over this long sea cable. To solve this problem, I adapted an existing data logger to provide power and log data from the OPC locally on

Study of wavelength division multiplexing as a means of increasing the number of channels in multimode fiber optic communication links

NASA Technical Reports Server (NTRS)

Bates, Harry

1990-01-01

A number of optical communication lines are now in use at the Kennedy Space Center (KSC) for the transmission of voice, computer data, and video signals. Presently, all of these channels utilize a single carrier wavelength centered near 1300 nm. The theoretical bandwidth of the fiber far exceeds the utilized capacity. Yet, practical considerations limit the usable bandwidth. The fibers have the capability of transmitting a multiplicity of signals simultaneously in each of two separate bands (1300 and 1550 nm). Thus, in principle, the number of transmission channels can be increased without installing new cable if some means of wavelength division multiplexing (WDM) can be utilized. The main goal of these experiments was to demonstrate that a factor of 2 increase in bandwidth utilization can share the same fiber in both a unidirectional configuration and a bidirectional mode of operation. Both signal and multimode fiber are installed at KSC. The great majority is multimode; therefore, this effort concentrated on multimode systems.

Apparatus for injecting high power laser light into a fiber optic cable

DOEpatents

Sweatt, William C.

1997-01-01

High intensity laser light is evenly injected into an optical fiber by the combination of a converging lens and a multisegment kinoform (binary optical element). The segments preferably have multi-order gratings on each which are aligned parallel to a radial line emanating from the center of the kinoform and pass through the center of the element. The grating in each segment causes circumferential (lateral) dispersion of the light, thereby avoiding detrimental concentration of light energy within the optical fiber.

Fiberoptics technology and its application to propulsion control systems

NASA Technical Reports Server (NTRS)

Baumbick, R. J.

1983-01-01

Current work on optical sensors and optically controlled actuators for use in air-breathing engine control systems is reviewed with particular reference to the design and operation of several new fiber-optic devices. These include a tachometer, a rotary position encoder, a Fabry-Perot interferometer and a rare-earth sensor for measuring engine gas temperatures, a high-temperature photoswitch designed for the range -55 to 260 C, and optical cables and connectors. The advantages of optics over conventional wire systems used for sensing and actuator control are briefly discussed.

Impedance self-matching ultra-narrow linewidth fiber resonator by use of a tunable π-phase-shifted FBG.

PubMed

Jing, Mingyong; Yu, Bo; Hu, Jianyong; Hou, Huifang; Zhang, Guofeng; Xiao, Liantuan; Jia, Suotang

2017-05-15

In this paper, we present a novel ultra-narrow linewidth fiber resonator formed by a tunable polarization maintaining (PM) π-phase-shifted fiber Bragg grating and a PM uniform fiber Bragg grating with a certain length of PM single mode fiber patch cable between them. Theoretical prediction shows that this resonator has ultra-narrow linewidth resonant peaks and is easy to realize impedance matching. We experimentally obtain 3 MHz narrow linewidth impedance matched resonant peak in a 7.3 m ultra-long passive fiber cavity. The impedance self-matching characteristic of this resonator also makes itself particularly suitable for use in ultra-sensitive sensors, ultra-narrow band rejection optical filters and fiber lasers applications.

Fatigue properties of superelastic Ti-Ni filaments and braided cables for bone fixation.

PubMed

Baril, Y; Brailovski, V

2010-02-01

This work is focused on the fatigue properties of the braided hollow tubular cables for bone fixation made of superelastic Ti-Ni filaments. To evaluate the fatigue life of the cable and the impact of braiding on fatigue life, a comparative study was conducted on both the braided cable and the single filament. The results of strain-controlled fatigue testing under variable mean and alternating strain conditions demonstrated that: (a) even though alternating strain is the most influent parameter, mean strain also has a significant impact on the fatigue life of both the filament and the braid; an improvement in the braided cable's fatigue life is observed under mean strains corresponding to the middle of the superelastic loop plateau; and (b) run-out (10(5) cycles) is reached at 1% of alternating strain for the filament, and at 0.3% for the braided cable. It was proved that the negative impact of braiding on fatigue life is caused: (a) by friction-induced damage of the braided filaments during cable manufacturing and (b) by locally occurring bending in the vicinity of the filaments' crossing, combined with the interfilament fretting during repetitive stretching of the braided cable.

Determination of ac conductor and pipe loss in pipe-type cable systems. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silver, D.A.; Seman, G.W.

1982-02-01

The results are presented of investigations into the determination of the ac/dc resistance ratios of high and extra high voltage pipe-type cables with conventional and large size segmental conductors in carbon steel, stainless steel and aluminum pipes in three cable per pipe and single cable per pipe configurations. The measurements included 115 through 765 kV cables with copper, enamel coated copper, and aluminum conductors in sizes of 2000 kcmil (1015 mm/sup 2/), 3250 kcmil (1650 mm/sup 2/), and 3500 kcmil (1776 mm/sup 2/). Calculations using presently available techniques were employed to provide correlation between measured and calculated values in bothmore » magnetic and non-magnetic pipes. In addition, a number of new techniques in conductor construction, pipe material and pipe liners and cable wraps were investigated as means of decreasing the ac/dc resistance ratios of pipe-type cables. Finally, the various systems studied were compared on the basis of system MVA rating and by evaluation of installed and overall operating costs as compared to conventional three cable per pipe systems installed in carbon steel pipes.« less

Measurement of water pressure and deformation with time domain reflectometry cables

NASA Astrophysics Data System (ADS)

Dowding, Charles H.; Pierce, Charles E.

1995-05-01

Time domain reflectometry (TDR) techniques can be deployed to measure water pressures and relative dam abutment displacement with an array of coaxial cables either drilled and grouted or retrofitted through existing passages. Application of TDR to dam monitoring requires determination of appropriate cable types and methods to install these cables in existing dams or during new construction. This paper briefly discusses currently applied and developing TDR techniques and describes initial design considerations for TDR-based dam instrumentation. Water pressure at the base of or within the dam can be determined by measuring the water level within a hollow or air-filled coaxial cable. The ability to retrofit existing porous stone-tipped piezometers is an attractive attribute of the TDR system. Measurement of relative lateral movement can be accomplished by monitoring local shearing of a solid polyethylene-filled coaxial cable at the interface of the dam base and foundation materials or along adversely oriented joints. Uplift can be recorded by measuring cable extension as the dam displaces upward off its foundation. Since each monitoring technique requires measurements with different types of coaxial cables, a variety may be installed within the array. Multiplexing of these cables will allow monitoring from a single pulser, and measurements can be recorded on site or remotely via a modem at any time.

Rapid cable tension estimation using dynamic and mechanical properties

NASA Astrophysics Data System (ADS)

Martínez-Castro, Rosana E.; Jang, Shinae; Christenson, Richard E.

2016-04-01

Main tension elements are critical to the overall stability of cable-supported bridges. A dependable and rapid determination of cable tension is desired to assess the state of a cable-supported bridge and evaluate its operability. A portable smart sensor setup is presented to reduce post-processing time and deployment complexity while reliably determining cable tension using dynamic characteristics extracted from spectral analysis. A self-recording accelerometer is coupled with a single-board microcomputer that communicates wirelessly with a remote host computer. The portable smart sensing device is designed such that additional algorithms, sensors and controlling devices for various monitoring applications can be installed and operated for additional structural assessment. The tension-estimating algorithms are based on taut string theory and expand to consider bending stiffness. The successful combination of cable properties allows the use of a cable's dynamic behavior to determine tension force. The tension-estimating algorithms are experimentally validated on a through-arch steel bridge subject to ambient vibration induced by passing traffic. The tension estimation is determined in well agreement with previously determined tension values for the structure.

Analytical investigation in bending characteristic of twisted stacked-tape cable conductor

NASA Astrophysics Data System (ADS)

Takayasu, Makoto; Chiesa, Luisa

2015-12-01

An analytical model to evaluate bending strains of a twisted stack-tape cable (TSTC) conductor has been developed. Through a comparison with experimental results obtained for a soldered 32-tape YBCO TSTC conductor, it has been found that a Perfect-Slip Model (PSM) taking into account the slipping between tapes in a stacked-tape cable during bending gives much better estimation of the bending performance compared to a No-Slip Model (NSM). In the PSM case the tapes can slip so that the internal longitudinal axial strain can be released. The longitudinal strains of compression and tension regions along the tape are balanced in one twist-pitch and cancel out evenly in a long cable. Therefore, in a cable the strains due to bending can be minimized. This is an important advantage of a TSTC conductor. The effect of the cable diameter size on the bending strain is also expected to be minor, and all tapes composing a TSTC conductor have the same strain response under bending, therefore the cable critical current can be characterized from a single tape behaviour.

Building Blueprints: Looking Toward the Future.

ERIC Educational Resources Information Center

College Planning & Management, 2001

2001-01-01

Highlights Kent State University's (Ohio) conversion of its physical education building to a technology building that features fiber optics and advanced cabling systems. Photos and a floor plan are included. (GR)

Transmission of Information: An Overview.

ERIC Educational Resources Information Center

Thoma, George R.

1981-01-01

Outlines the basic principles underlying the transmission of information, including analog and digital modulation, limitations to communications, configurations of communications networks, optical fiber cables, and earth satellites. Six references are cited. (FM)

A two-step FEM-SEM approach for wave propagation analysis in cable structures

NASA Astrophysics Data System (ADS)

Zhang, Songhan; Shen, Ruili; Wang, Tao; De Roeck, Guido; Lombaert, Geert

2018-02-01

Vibration-based methods are among the most widely studied in structural health monitoring (SHM). It is well known, however, that the low-order modes, characterizing the global dynamic behaviour of structures, are relatively insensitive to local damage. Such local damage may be easier to detect by methods based on wave propagation which involve local high frequency behaviour. The present work considers the numerical analysis of wave propagation in cables. A two-step approach is proposed which allows taking into account the cable sag and the distribution of the axial forces in the wave propagation analysis. In the first step, the static deformation and internal forces are obtained by the finite element method (FEM), taking into account geometric nonlinear effects. In the second step, the results from the static analysis are used to define the initial state of the dynamic analysis which is performed by means of the spectral element method (SEM). The use of the SEM in the second step of the analysis allows for a significant reduction in computational costs as compared to a FE analysis. This methodology is first verified by means of a full FE analysis for a single stretched cable. Next, simulations are made to study the effects of damage in a single stretched cable and a cable-supported truss. The results of the simulations show how damage significantly affects the high frequency response, confirming the potential of wave propagation based methods for SHM.

First year of practical experiences of the new Arctic AWIPEV-COSYNA cabled Underwater Observatory in Kongsfjorden, Spitsbergen

NASA Astrophysics Data System (ADS)

Fischer, Philipp; Schwanitz, Max; Loth, Reiner; Posner, Uwe; Brand, Markus; Schröder, Friedhelm

2017-04-01

A combined year-round assessment of selected oceanographic data and a macrobiotic community assessment was performed from October 2013 to November 2014 in the littoral zone of the Kongsfjorden polar fjord system on the western coast of Svalbard (Norway). State of the art remote controlled cabled underwater observatory technology was used for daily vertical profiles of temperature, salinity, and turbidity together with a stereo-optical assessment of the macrobiotic community, including fish. The results reveal a distinct seasonal cycle in total species abundances, with a significantly higher total abundance and species richness during the polar winter when no light is available underwater compared to the summer months when 24 h light is available. During the winter months, a temporally highly segmented community was observed with respect to species occurrence, with single species dominating the winter community for restricted times. In contrast, the summer community showed an overall lower total abundance as well as a significantly lower number of species. The study clearly demonstrates the high potential of cable connected remote controlled digital sampling devices, especially in remote areas, such as polar fjord systems, with harsh environmental conditions and limited accessibility. A smart combination of such new digital sampling methods with classic sampling procedures can provide a possibility to significantly extend the sampling time and frequency, especially in remote and difficult to access areas. This can help to provide a sufficient data density and therefore statistical power for a sound scientific analysis without increasing the invasive sampling pressure in ecologically sensitive environments.

Measuring the Dispersion Curve of a PMMA-Fibre Optic Cable Using a Dye Laser

ERIC Educational Resources Information Center

Zorba, Serkan; Farah, Constantine; Pant, Ravi

2010-01-01

An advanced undergraduate laboratory experiment is outlined which uses a dye laser to map out the chromatic dispersion curve of a polymethyl methacrylate (PMMA) optical fibre. Seven different wavelengths across the visible spectrum are employed using five different dyes. The light pulse is split into two pulses, one to a nearby photodetector and…

Aircraft lightning-induced voltage test technique developments

NASA Technical Reports Server (NTRS)

Crouch, K. E.

1983-01-01

High voltage safety, fuels safety, simulation, and response/measurement techniques are discussed. Travelling wave transit times, return circuit conductor configurations, LC ladder network generators, and repetitive pulse techniques are also discussed. Differential conductive coaxial cable, analog fiber optic link, repetitive pulse sampled data instrumentation system, flash A/D optic link system, and an FM telemetry system are considered.

No moving parts safe & arm apparatus and method with monitoring and built-in-test for optical firing of explosive systems

DOEpatents

Hendrix, J.L.

1995-04-11

A laser initiated ordnance controller apparatus which provides a safe and arm scheme with no moving parts. The safe & arm apparatus provides isolation of firing energy to explosive devices using a combination of polarization isolation and control through acousto-optical deviation of laser energy pulses. The apparatus provides constant monitoring of the systems status and performs 100% built-in-test at any time prior to ordnance ignition without the risk of premature ignition or detonation. The apparatus has a computer controller, a solid state laser, an acousto-optic deflector and RF drive circuitry, built-in-test optics and electronics, and system monitoring capabilities. The optical system is completed from the laser beam power source to the pyrotechnic ordnance through fiber optic cabling, optical splitters and optical connectors. During operation of the apparatus, a command is provided by the computer controller and, simultaneous with laser flashlamp fire, the safe & arm device is opened for approximately 200 microseconds which allows the laser pulse to transmit through the device. The arm signal also energizes the laser power supply and activates the acousto-optical deflector. When the correct fire format command is received, the acousto-optic deflector moves to the selected event channel, and the channel is verified to ensure the system is pointing to the correct position. Laser energy is transmitted through the fiber where an ignitor or detonator designed to be sensitive to optical pulses is fired at the end of the fiber channel. Simultaneous event channels may also be utilized by optically splitting a single event channel. The built-in-test may be performed anytime prior to ordnance ignition. 6 figures.

No moving parts safe & arm apparatus and method with monitoring and built-in-test for optical firing of explosive systems

DOEpatents

Hendrix, James L.

1995-01-01

A laser initiated ordnance controller apparatus which provides a safe and m scheme with no moving parts. The safe & arm apparatus provides isolation of firing energy to explosive devices using a combination of polarization isolation and control through acousto-optical deviation of laser energy pulses. The apparatus provides constant monitoring of the systems status and performs 100% built-in-test at any time prior to ordnance ignition without the risk of premature ignition or detonation. The apparatus has a computer controller, a solid state laser, an acousto-optic deflector and RF drive circuitry, built-in-test optics and electronics, and system monitoring capabilities. The optical system is completed from the laser beam power source to the pyrotechnic ordnance through fiber optic cabling, optical splitters and optical connectors. During operation of the apparatus, a command is provided by the computer controller and, simultaneous with laser flashlamp fire, the safe & arm device is opened for approximately 200 microseconds which allows the laser pulse to transmit through the device. The arm signal also energizes the laser power supply and activates the acousto-optical deflector. When the correct fire format command is received, the acousto-optic deflector moves to the selected event channel, and the channel is verified to ensure the system is pointing to the correct position. Laser energy is transmitted through the fiber where an ignitor or detonator designed to be sensitive to optical pulses is fired at the end of the fiber channel. Simultaneous event channels may also be utilized by optically splitting a single event channel. The built-in-test may be performed anytime prior to ordnance ignition.

Acoustic emission monitoring of CFRP cables for cable-stayed bridges

NASA Astrophysics Data System (ADS)

Rizzo, Piervincenzo; Lanza di Scalea, Francesco

2001-08-01

The advantages of fiber-reinforced polymer (FRP) composite include excellent corrosion resistance, high specific strength and stiffness, as well as outstanding fatigue behavior. The University of California San Diego's I- 5/Gilman Advanced Technology Bridge Project will help demonstrating the use of such materials in civil infrastructures. This paper presents an acoustic emission (AE) study performed during laboratory proof tests of carbon fiber-reinforced polymer stay-cables of possible use in the I-5/Gilman bridge. Three types of cables, both braided and single strand, were tested to failure at lengths ranging from 5500 mm to 5870 mm. AE allowed to monitor damage initiation and progression in the test pieces more accurately than the conventional load versus displacement curve. All of the cables exhibited acoustic activities revealing some degree of damage well before reaching final collapse, which is expected in FRP's. It was also shown that such cables are excellent acoustic waveguides exhibiting very low acoustic attenuation, which makes them an ideal application for an AE-based health monitoring approach.

Inorganic scintillation detectors based on Eu-activated phosphors for 192Ir brachytherapy

PubMed Central

Kertzscher, Gustavo; Beddar, Sam

2017-01-01

The availability of real-time treatment verification during high-dose-rate (HDR) brachytherapy is currently limited. Therefore, we studied the luminescence properties of the widely commercially available scintillators using the inorganic materials Eu-activated phosphors Y2O3:Eu, YVO4:Eu, Y2O2S:Eu, and Gd2O2S:Eu to determine whether they could be used to accurately and precisely verify HDR brachytherapy doses in real time. The suitability for HDR brachytherapy of inorganic scintillation detectors (ISDs) based on the 4 Eu-activated phosphors in powder form was determined based on experiments with a 192Ir HDR brachytherapy source. The scintillation intensities of the phosphors were 16 to 134 times greater than that of the commonly used organic plastic scintillator BCF-12. High signal intensities were achieved with an optimized packing density of the phosphor mixture and with a shortened fiber-optic cable. The influence of contaminating Cerenkov and fluorescence light induced in the fiber-optic cable (stem signal) was adequately suppressed by inserting between the fiber-optic cable and the photodetector a 25-nm band-pass filter centered at the emission peak. The spurious photoluminescence signal induced by the stem signal was suppressed by placing a long-pass filter between the scintillation detector volume and the fiber-optic cable. The time-dependent luminescence properties of the phosphors were quantified by measuring the non-constant scintillation during irradiation and the afterglow after the brachytherapy source had retracted. We demonstrated that a mixture of Y2O3:Eu and YVO4:Eu suppressed the time-dependence of the ISDs and that the time-dependence of Y2O2S:Eu and Gd2O2S:Eu introduced large measurement inaccuracies. We conclude that ISDs based on a mixture of Y2O3:Eu and YVO4:Eu are promising candidates for accurate and precise real-time verification technology for HDR BT that is cost effective and straightforward to manufacture. Widespread dissemination of this technology could lead to an improved understanding of error types and frequencies during BT and to improved patient safety during treatment. PMID:28475494

Inorganic scintillation detectors based on Eu-activated phosphors for 192Ir brachytherapy

NASA Astrophysics Data System (ADS)

Kertzscher, Gustavo; Beddar, Sam

2017-06-01

The availability of real-time treatment verification during high-dose-rate (HDR) brachytherapy is currently limited. Therefore, we studied the luminescence properties of the widely commercially available scintillators using the inorganic materials Eu-activated phosphors Y2O3:Eu, YVO4:Eu, Y2O2S:Eu, and Gd2O2S:Eu to determine whether they could be used to accurately and precisely verify HDR brachytherapy doses in real time. The suitability for HDR brachytherapy of inorganic scintillation detectors (ISDs) based on the 4 Eu-activated phosphors in powder form was determined based on experiments with a 192Ir HDR brachytherapy source. The scintillation intensities of the phosphors were 16-134 times greater than that of the commonly used organic plastic scintillator BCF-12. High signal intensities were achieved with an optimized packing density of the phosphor mixture and with a shortened fiber-optic cable. The influence of contaminating Cerenkov and fluorescence light induced in the fiber-optic cable (stem signal) was adequately suppressed by inserting between the fiber-optic cable and the photodetector a 25 nm band-pass filter centered at the emission peak. The spurious photoluminescence signal induced by the stem signal was suppressed by placing a long-pass filter between the scintillation detector volume and the fiber-optic cable. The time-dependent luminescence properties of the phosphors were quantified by measuring the non-constant scintillation during irradiation and the afterglow after the brachytherapy source had retracted. We demonstrated that a mixture of Y2O3:Eu and YVO4:Eu suppressed the time-dependence of the ISDs and that the time-dependence of Y2O2S:Eu and Gd2O2S:Eu introduced large measurement inaccuracies. We conclude that ISDs based on a mixture of Y2O3:Eu and YVO4:Eu are promising candidates for accurate and precise real-time verification technology for HDR BT that is cost effective and straightforward to manufacture. Widespread dissemination of this technology could lead to an improved understanding of error types and frequencies during BT and to improved patient safety during treatment.

30 CFR 56.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... circuit used to fire one or more electric blasting caps. Blasting switch means a switch used to connect a... circuit is carried to one or more cables from a single incoming feed line, each cable circuit being... or salary in the service of an employer. Employer means a person or organization which hires one or...

30 CFR 56.2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... circuit used to fire one or more electric blasting caps. Blasting switch means a switch used to connect a... circuit is carried to one or more cables from a single incoming feed line, each cable circuit being... or salary in the service of an employer. Employer means a person or organization which hires one or...

30 CFR 56.2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... circuit used to fire one or more electric blasting caps. Blasting switch means a switch used to connect a... circuit is carried to one or more cables from a single incoming feed line, each cable circuit being... or salary in the service of an employer. Employer means a person or organization which hires one or...

Transabdominal wall deployment for instruments, lights, and micromotors using the concept of secured independent tools.

PubMed

Tsin, Daniel A; Davila, Fausto; Dominguez, Guillermo; Tinelli, Andrea; Davila, Martha R

2012-05-01

Use of secured independent tools (SIT) is changing the laparoscopy paradigm, which involves the use of instruments inside the abdominal cavity that are operated via a port that is larger in diameter than the instrument itself. However, in SIT instead of ports we used filaments or cables. Here we describe a modified SIT for use in the introduction of sutures or cables inside the peritoneum. Cables or sutures are passed through a tunnel made by an intravenous catheter and then exteriorized via a 12-mm port for tying, plugging (attaching), or connecting to different types of devices such as an endoscopic bulldog, alligator clamps, lights, and micromotors. These devices are introduced inside the abdomen and remotely operated with cables or filaments. The use of SIT is not limited to laparoscopy; it was successfully used in clinical experiences of single-port and single-incision laparoscopy and could facilitate natural orifice surgery. The technique offers a good force for traction, retraction, and mobilization. In addition, it has transmission capabilities for cameras and may facilitate the placement of wired microrobotics.

New Opportunities for Cabled Ocean Observatories

NASA Astrophysics Data System (ADS)

Duennebier, F. K.; Butler, R.; Karl, D. M.; Roger, L. B.

2002-12-01

With the decommissioning of transoceanic telecommunications cables as they become obsolete or uneconomical, there is an opportunity to use these systems for ocean observatories. Two coaxial cables, TPC-1 and HAW-2 are currently in use for observatories, and another, ANZCAN, is scheduled to be used beginning in 2004 to provide a cabled observatory at Station ALOHA, north of Oahu. The ALOHA observatory will provide several Mb/s data rates and about 1 kW of power to experiments installed at Station ALOHA. Sensors can be installed either by wet mateable connection to a junction box on the ocean floor using an ROV, or by acoustic data link to the system. In either case real-time data will be provided to users over the Internet. A Small Experiment Module, to be first installed at the Hawaii-2 Observatory, and later at Station ALOHA, will provide relatively cheap and uncomplicated access to the observatories for relatively simple sensors. Within the next few years, the first electro-optical cables installed in the 1980's will be decommissioned and could be available for scientific use. These cables could provide long "extension cords" (thousands of km) with very high bandwidth and reasonable power to several observatories in remote locations in the ocean. While they could be used in-place, a more exciting scenario is to use cable ships to pick up sections of cable and move them to locations of higher scientific interest. While such moves would not be cheap, the costs would rival the cost of installation and maintenance of a buoyed observatory, with far more bandwidth and power available for science use.

MRI dynamic range and its compatibility with signal transmission media

PubMed Central

Gabr, Refaat E.; Schär, Michael; Edelstein, Arthur D.; Kraitchman, Dara L.; Bottomley, Paul A.; Edelstein, William A.

2010-01-01

As the number of MRI phased array coil elements grows, interactions among cables connecting them to the system receiver become increasingly problematic. Fiber optic or wireless links would reduce electromagnetic interference, but their dynamic range (DR) is generally less than that of coaxial cables. Raw MRI signals, however, have a large DR because of the high signal amplitude near the center of k-space. Here, we study DR in MRI in order to determine the compatibility of MRI multicoil imaging with non-coaxial cable signal transmission. Since raw signal data are routinely discarded, we have developed an improved method for estimating the DR of MRI signals from conventional magnitude images. Our results indicate that the DR of typical surface coil signals at 3 T for human subjects is less than 88 dB, even for three-dimensional acquisition protocols. Cardiac and spine coil arrays had a maximum DR of less than 75 dB and head coil arrays less than 88 dB. The DR derived from magnitude images is in good agreement with that measured from raw data. The results suggest that current analog fiber optic links, with a spurious-free DR of 60–70 dB at 500 kHz bandwidth, are not by themselves adequate for transmitting MRI data from volume or array coils with DR ~90 dB. However, combining analog links with signal compression might make non-coaxial cable signal transmission viable. PMID:19251444

MRI dynamic range and its compatibility with signal transmission media.

PubMed

Gabr, Refaat E; Schär, Michael; Edelstein, Arthur D; Kraitchman, Dara L; Bottomley, Paul A; Edelstein, William A

2009-06-01

As the number of MRI phased array coil elements grows, interactions among cables connecting them to the system receiver become increasingly problematic. Fiber optic or wireless links would reduce electromagnetic interference, but their dynamic range (DR) is generally less than that of coaxial cables. Raw MRI signals, however, have a large DR because of the high signal amplitude near the center of k-space. Here, we study DR in MRI in order to determine the compatibility of MRI multicoil imaging with non-coaxial cable signal transmission. Since raw signal data are routinely discarded, we have developed an improved method for estimating the DR of MRI signals from conventional magnitude images. Our results indicate that the DR of typical surface coil signals at 3T for human subjects is less than 88 dB, even for three-dimensional acquisition protocols. Cardiac and spine coil arrays had a maximum DR of less than 75 dB and head coil arrays less than 88 dB. The DR derived from magnitude images is in good agreement with that measured from raw data. The results suggest that current analog fiber optic links, with a spurious-free DR of 60-70 dB at 500 kHz bandwidth, are not by themselves adequate for transmitting MRI data from volume or array coils with DR approximately 90 dB. However, combining analog links with signal compression might make non-coaxial cable signal transmission viable.

Civionics specifications for fiber optic sensors for structural health monitoring

NASA Astrophysics Data System (ADS)

Rivera, Evangeline; Mufti, Aftab A.; Thomson, Douglas J.

2004-07-01

As the design and construction of civil structures continue to evolve, it is becoming imperative that these structures be monitored for their health. In order to meet this need, the discipline of Civionics has emerged. It involves the applications to civil structures and aims to assist engineers in realizing the full benefits of structural health monitoring (SHM). Therefore, the goal of the specification outlined in this work is to ensure that correct installation and operating of fiber optic sensors, such as bridges, will be discussed that motivated the writing of these specifications. The main reason for the failure of FOS based monitoring systems can be traced directly to the installation of the fiber sensor itself. Therefore, by creating a standard procedure for SHM, several ambiguities are eliminated such as fiber sensor specifications and the types of cables required. As a result, these specifications will help ensure that the sensors will survive the installation process and eventually prove their value over years of monitoring the health of the structure. The Civionics FOS specifications include the requirements for fiber sensors, specifically Bragg grating sensors, and their corresponding readout unit. It also includes specifications on the cables, conduits, junction boxes, cable termination and the environmental.

Strain and ground-motion monitoring at magmatic areas: ultra-long and ultra-dense networks using fibre optic sensing systems

NASA Astrophysics Data System (ADS)

Jousset, Philippe; Reinsch, Thomas; Henninges, Jan; Blanck, Hanna; Ryberg, Trond

2016-04-01

The fibre optic distributed acoustic sensing technology (DAS) is a "new" sensing system for exploring earth crustal elastic properties and monitoring both strain and seismic waves with unprecedented acquisition characteristics. The DAS technology principle lies in sending successive and coherent pulses of light in an optical fibre and measuring the back-scattered light issued from elastic scattering at random defaults within the fibre. The read-out unit includes an interferometer, which measures light interference patterns continuously. The changes are related to the distance between such defaults and therefore the strain within the fibre can be detected. Along an optical fibre, DAS can be used to acquire acoustic signals with a high spatial (every meter over kilometres) and high temporal resolution (thousand of Hz). Fibre optic technologies were, up to now, mainly applied in perimeter surveillance applications and pipeline monitoring and in boreholes. Previous experiments in boreholes have shown that the DAS technology is well suited for probing subsurface elastic properties, showing new ways for cheaper VSP investigations of the Earth crust. Here, we demonstrate that a cable deployed at ground surface can also help in exploring subsurface properties at crustal scale and monitor earthquake activity in a volcanic environment. Within the framework of the EC funded project IMAGE, we observed a >15 km-long fibre optic cable at the surface connected to a DAS read-out unit. Acoustic data was acquired continuously for 9 days. Hammer shots were performed along the surface cable in order to locate individual acoustic traces and calibrate the spatial distribution of the acoustic information. During the monitoring period both signals from on- and offshore explosive sources and natural seismic events could be recorded. We compare the fibre optic data to conventional seismic records from a dense seismic network deployed on Reykjanes. We show that we can probe and monitor earth crust subsurface with dense acquisition of the ground motion, both in space and in time and over a broad band frequency range.

A new method of combined techniques for characterization and monitoring of seawater interface in an alluvial aquifer

NASA Astrophysics Data System (ADS)

Folch, Albert; del Val, Laura; Luquot, Linda; Martínez, Laura; Bellmunt, Fabian; Le Lay, Hugo; Rodellas, Valentí; Ferrer, Núria; Fernández, Sheila; Ledo, Juanjo; Pezard, Philippe; Bour, Olivier; Queralt, Pilar; Marcuello, Alex; García-Orellana, Jordi; Saaltink, Maarten; Vázquez-Suñé, Enric; Carrera, Jesús

2016-04-01

Understand the dynamics of the fresh-salt water interface in aquifers is a key issue to comprehend mixing process and to quantity the discharge of nutrients in to coastal areas. In order to go beyond the current knowledge in this issue an experimental site has been set up at the alluvial aquifer Riera Argentona (Barcelona - Spain). The site comprises 16 shallow piezometers installed between 30 and 90 m from the seashore, with depths ranging between 15 and 25 meters. The seawater interface is being monitored using several techniques, the combination of which will help us to understand the spatial and temporal behaviour of the mixing zone and the geochemical processes occurring there. Specially the deepest piezometers are equipped with electrodes in order to perform cross-hole electrical resistivity tomography (CHERT). In addition, all piezometers are also equipped with Fiber Optic cable to perform distributed temperature measurements. Two single steel armoured fibre optic cable lines of around 600m length were installed in all boreholes. The objective is to use the cable both as passive and active temperature sensor. The first is being done for the continuous monitoring of temperature whereas; the second provides a higher temperature resolution used to monitor field experiments. Periodic CHERT measurements are carried out between the piezometer equipped with electrodes, resulting in parallel and perpendicular vertical cross sections of the site resistivity. The position of the fresh-salt water interface can be identified due to the resistivity contrast between the saline and fresh water. Preliminary results of periodic distributed temperature measurements will be also be used to monitor the position of the mixing zone thanks to the contrast and seasonal temperature changes. Periodic down-hole EC profiles will be used to validate the method. Acknowledgements This work was funded by the projects CGL2013-48869-C2-1 y CGL2013-48869-C2-2-R of the Spanish Government. We would like to thank SIMMAR (Serveis Integrals de Manteniment del Maresme) and the Consell Comarcal del Maresme in the construction of the research site.

Telecommunications and Information Services in Brazil.

ERIC Educational Resources Information Center

Tarapanoff, Kira; Alvares, Lillian

1995-01-01

Discusses the interdependence of telecommunications and information sciences in Brazil. Highlights include new technologies and telecommunications: satellites, fiber optic cables, data communication networks, information superhighways, and cooperative projects; and information services development. (AEF)

Temperature- and field-dependent characterization of a conductor on round core cable

NASA Astrophysics Data System (ADS)

Barth, C.; van der Laan, D. C.; Bagrets, N.; Bayer, C. M.; Weiss, K.-P.; Lange, C.

2015-06-01

The conductor on round core (CORC) cable is one of the major high temperature superconductor cable concepts combining scalability, flexibility, mechanical strength, ease of fabrication and high current density; making it a possible candidate as conductor for large, high field magnets. To simulate the boundary conditions of such magnets as well as the temperature dependence of CORC cables a 1.16 m long sample consisting of 15, 4 mm wide SuperPower REBCO tapes was characterized using the ‘FBI’ (force—field—current) superconductor test facility of the Institute for Technical Physics of the Karlsruhe Institute of Technology. In a five step investigation, the CORC cable’s performance was determined at different transverse mechanical loads, magnetic background fields and temperatures as well as its response to swift current changes. In the first step, the sample’s 77 K, self-field current was measured in a liquid nitrogen bath. In the second step, the temperature dependence was measured at self-field condition and compared with extrapolated single tape data. In the third step, the magnetic background field was repeatedly cycled while measuring the current carrying capabilities to determine the impact of transverse Lorentz forces on the CORC cable sample’s performance. In the fourth step, the sample’s current carrying capabilities were measured at different background fields (2-12 T) and surface temperatures (4.2-51.5 K). Through finite element method simulations, the surface temperatures are converted into average sample temperatures and the gained field- and temperature dependence is compared with extrapolated single tape data. In the fifth step, the response of the CORC cable sample to rapid current changes (8.3 kA s-1) was observed with a fast data acquisition system. During these tests, the sample performance remains constant, no degradation is observed. The sample’s measured current carrying capabilities correlate to those of single tapes assuming field- and temperature dependence as published by the manufacturer.

Distributed gas sensing with optical fibre photothermal interferometry.

PubMed

Lin, Yuechuan; Liu, Fei; He, Xiangge; Jin, Wei; Zhang, Min; Yang, Fan; Ho, Hoi Lut; Tan, Yanzhen; Gu, Lijuan

2017-12-11

We report the first distributed optical fibre trace-gas detection system based on photothermal interferometry (PTI) in a hollow-core photonic bandgap fibre (HC-PBF). Absorption of a modulated pump propagating in the gas-filled HC-PBF generates distributed phase modulation along the fibre, which is detected by a dual-pulse heterodyne phase-sensitive optical time-domain reflectometry (OTDR) system. Quasi-distributed sensing experiment with two 28-meter-long HC-PBF sensing sections connected by single-mode transmission fibres demonstrated a limit of detection (LOD) of ∼10 ppb acetylene with a pump power level of 55 mW and an effective noise bandwidth (ENBW) of 0.01 Hz, corresponding to a normalized detection limit of 5.5ppb⋅W/Hz. Distributed sensing experiment over a 200-meter-long sensing cable made of serially connected HC-PBFs demonstrated a LOD of ∼ 5 ppm with 62.5 mW peak pump power and 11.8 Hz ENBW, or a normalized detection limit of 312ppb⋅W/Hz. The spatial resolution of the current distributed detection system is limited to ∼ 30 m, but it is possible to reduce down to 1 meter or smaller by optimizing the phase detection system.

Spatially resolved, diffuse reflectance imaging for subsurface pattern visualization toward development of a lensless imaging platform: phantom experiments

NASA Astrophysics Data System (ADS)

Schelkanova, Irina; Pandya, Aditya; Saiko, Guennadi; Nacy, Lidia; Babar, Hannan; Shah, Duoaud; Lilge, Lothar; Douplik, Alexandre

2016-01-01

A portable, spatially resolved, diffuse reflectance lensless imaging technique based on the charge-coupled device or complementary metal-oxide semiconductor sensor directly coupled to the fiber optic bundle is proposed for visualization of subsurface structures such as superficial microvasculature in the epithelium. We discuss an experimental method for emulating a lensless imaging setup via raster scanning a single fiber-optic cable over a microfluidic phantom containing periodic hemoglobin absorption contrast. To evaluate the ability of the technique to recover information about the subsurface linear structures, scattering layers formed of the Sylgard® 184 Silicone Elastomer and titanium dioxide were placed atop the microfluidic phantom. Thickness of the layers ranged from 0.2 to 0.7 mm, and the values of the reduced scattering coefficient (μs‧) were between 0.85 and 4.25 mm-1. The results demonstrate that fiber-optic, lensless platform can be used for two-dimensional imaging of absorbing inclusions in diffuse reflectance mode. In these experiments, it was shown that diffuse reflectance imaging can provide sufficient spatial sampling of the phantom for differentiation of 30 μm structural features of the embedded absorbing pattern inside the scattering media.

Automatic detection of ECG cable interchange by analyzing both morphology and interlead relations.

PubMed

Han, Chengzong; Gregg, Richard E; Feild, Dirk Q; Babaeizadeh, Saeed

2014-01-01

ECG cable interchange can generate erroneous diagnoses. For algorithms detecting ECG cable interchange, high specificity is required to maintain a low total false positive rate because the prevalence of interchange is low. In this study, we propose and evaluate an improved algorithm for automatic detection and classification of ECG cable interchange. The algorithm was developed by using both ECG morphology information and redundancy information. ECG morphology features included QRS-T and P-wave amplitude, frontal axis and clockwise vector loop rotation. The redundancy features were derived based on the EASI™ lead system transformation. The classification was implemented using linear support vector machine. The development database came from multiple sources including both normal subjects and cardiac patients. An independent database was used to test the algorithm performance. Common cable interchanges were simulated by swapping either limb cables or precordial cables. For the whole validation database, the overall sensitivity and specificity for detecting precordial cable interchange were 56.5% and 99.9%, and the sensitivity and specificity for detecting limb cable interchange (excluding left arm-left leg interchange) were 93.8% and 99.9%. Defining precordial cable interchange or limb cable interchange as a single positive event, the total false positive rate was 0.7%. When the algorithm was designed for higher sensitivity, the sensitivity for detecting precordial cable interchange increased to 74.6% and the total false positive rate increased to 2.7%, while the sensitivity for detecting limb cable interchange was maintained at 93.8%. The low total false positive rate was maintained at 0.6% for the more abnormal subset of the validation database including only hypertrophy and infarction patients. The proposed algorithm can detect and classify ECG cable interchanges with high specificity and low total false positive rate, at the cost of decreased sensitivity for certain precordial cable interchanges. The algorithm could also be configured for higher sensitivity for different applications where a lower specificity can be tolerated. Copyright © 2014 Elsevier Inc. All rights reserved.

Virginia Offshore Wind Technology Advancement Project (VOWTAP) DOE EE0005985 Final Technical Report Rev 1a

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pietryk, Steven

The primary purpose of the VOWTAP was to advance the offshore wind industry in the United States (U.S.) by demonstrating innovative technologies and process solutions that would establish offshore wind as a cost-effective renewable energy resource. The VOWTAP Team proposed to design, construct, and operate a 12 megawatt (MW) offshore wind facility located approximately 27 statute miles (mi) (24 nautical miles [nm], 43 kilometers [km]) off the coast of Virginia. The proposed Project would consist of two Alstom Haliade™ 150-6 MW turbines mounted on inward battered guide structures (IBGS), a 34.5-kilovolt (kV) alternating current (AC) submarine cable interconnecting the WTGsmore » (inter-array cable), a 34.5-kV AC submarine transmission cable (export cable), and a 34.5 kV underground cable (onshore interconnection cable) that would connect the Project with existing Dominion infrastructure located in Virginia Beach, Virginia (Figure 1). Interconnection with the existing Dominion infrastructure would also require an onshore switch cabinet, a fiber optic cable, and new interconnection station to be located entirely within the boundaries of the Camp Pendleton State Military Reservation (Camp Pendleton). The VOWTAP balanced technology innovation with commercial readiness such that turbine operations were anticipated to commence by 2018. Dominion, as the leaseholder of the Virginia Wind Energy Area (WEA), anticipated leveraging lessons learned through the VOWTAP, and applying them to future commercial-scale offshore wind development.« less

ESONET LIDO Demonstration Mission: the East Sicily node

NASA Astrophysics Data System (ADS)

Riccobene, Giorgio; Favali, Paolo; Andrè, Michel; Chierici, Francesco; Pavan, Gianni; Esonet Lido Demonstration Mission Team

2010-05-01

Off East Sicily (at 2100 m depth, 25 km off the harbour of Catania) a prototype of a cabled deep-sea observatory (NEMO-SN1) was set up and has been operational in real-time since 2005 (the cabled deep-sea multi-parameter station SN1, equipped with geophysical and environmental sensors and the cabled NEMO-OνDE, equipped with 4 broadband hydrophones). The Western Ionian Sea is one of the node sites for the upcoming European permanent underwater network (EMSO). Within the activities of the EC project ESONET-NoE some demonstration missions have been funded. The LIDO-DM (Listening to the Deep Ocean-Demonstration Mission) is one of these and is related to two sites, East Sicily and Iberian Margin (Gulf of Cadiz), the main aims being geo-hazards monitoring and warning (seismic, tsunami, and volcanic) and bio-acoustics. The LIDO-DM East Sicily installation represents a further major step within ESONET-NoE, resulting in a fully integrated system for multidisciplinary deep-sea science, capable to transmit and distribute data in real time to the scientific community and to the general public. LIDO-DM East Sicily hosts a large number of sensors aimed at monitoring and studying oceanographic and environmental parameters (by means of CTD, ADCP, 3-C single point current meter, turbidity meter), geophysical phenomena (low frequency hydrophones, accelerometer, gravity meter, vector and scalar magnetometers, seismometer, absolute and differential pressure gauges), ocean noise monitoring and identification and tracking of biological acoustic sources in deep sea. The latter will be performed using two tetrahedral arrays of 4 hydrophones, located at a relative distance of about 5 km, and at about 25 km from the shore. The whole system will be connected and powered from shore, by means of the electro-optical cable net installed at the East Sicily Site Infrastructure, and synchronised with GPS. Sensors data sampling is performed underwater and transmitted via optical fibre link, with optimal S/N ratio for all signals. This will also permit real-time data acquisition, analysis and distribution on-shore. Innovative electronics for the off-shore data acquisition and transmission systems has been designed, built and tested. A dedicated computing and networking infrastructure for data acquisition, storage and distribution through the internet has been also created. The deployment and connection of the deep sea structures will be performed using the dedicated ROV and Deep Sea Shuttle handling facilities (PEGASO, owned by INGV and INFN). LIDO-DM constitutes the enhancement of the Western Ionian site in view of the EMSO Research Infrastructure.

Continuous monitoring of large civil structures using a digital fiber optic motion sensor system

NASA Astrophysics Data System (ADS)

Hodge, Malcolm H.; Kausel, Theodore C., Jr.

1998-03-01

There is no single attribute which can always predict structural deterioration. Accordingly, we have developed a scheme for monitoring a wide range of incipient deterioration parameters, all based on a single motion sensor concept. In this presentation, we describe how an intrinsically low power- consumption fiber optic harness can be permanently deployed to poll an array of optical sensors. The function and design of these simple, durable, and naturally digital sensors is described, along with the manner in which they have been configured to collect information for changes in the most important structural aspects. The SIMS system is designed to interrogate each sensor up to five-thousand times per second for the life of the structure, and to report sensor data back to a remote computer base for current and long-term analysis, and is directed primarily towards bridges. By suitably modifying the actuation of this very precise motion sensor, SIMS is able to track bridge deck deflection and vibration, expansion joint travel, concrete and rebar corrosion, pothole development, pier scour and tilt. Other sensors will track bolt clamp load, cable tension, and metal fatigue. All of these data are received within microseconds, which means that appropriate computer algorithm manipulations can be carried out to correlate one sensor with other sensors in real time. This internal verification feature automatically enhances confidence in the system's predictive ability and alerts the user to any anomalous behavior.

A movable-mass attitude stabilization system for cable-connected artificial-g space stations

NASA Technical Reports Server (NTRS)

Childs, D. W.; Hardison, T. L.

1974-01-01

The development of an active, momentum-exchange system to be used for attitude stabilization of a class of cable-connected artificial-g space stations is studied. A system which employs a single movable control mass is examined for the control of a space station which has the physical appearance of two cylinders connected axially by cables. The dynamic model for the space station includes its aggregate rigid body rotation and relative torsional rotation between the bodies. A zero torsional stiffness design (one cable) and a maximum torsional stiffness design (eight cables) are examined in various stages of deployment, for selected spin velocities ranging from 4 rpm upwards. A linear, time-invariant, feed-back control system is employed, with gains calculated via a root-specification procedure. The movable mass controller provides critical wobble-damping capability for the crew quarters for all configurations and spin velocity.

Multiscale stochastic simulations for tensile testing of nanotube-based macroscopic cables.

PubMed

Pugno, Nicola M; Bosia, Federico; Carpinteri, Alberto

2008-08-01

Thousands of multiscale stochastic simulations are carried out in order to perform the first in-silico tensile tests of carbon nanotube (CNT)-based macroscopic cables with varying length. The longest treated cable is the space-elevator megacable but more realistic shorter cables are also considered in this bottom-up investigation. Different sizes, shapes, and concentrations of defects are simulated, resulting in cable macrostrengths not larger than approximately 10 GPa, which is much smaller than the theoretical nanotube strength (approximately 100 GPa). No best-fit parameters are present in the multiscale simulations: the input at level 1 is directly estimated from nanotensile tests of CNTs, whereas its output is considered as the input for the level 2, and so on up to level 5, corresponding to the megacable. Thus, five hierarchical levels are used to span lengths from that of a single nanotube (approximately 100 nm) to that of the space-elevator megacable (approximately 100 Mm).

Development of a real-time radon monitoring system for simultaneous measurements in multiple sites

NASA Astrophysics Data System (ADS)

Yamamoto, S.; Yamasoto, K.; Iida, T.

1999-12-01

A real-time radon monitoring system that can simultaneously measure radon concentrations in multiple sites was developed and tested. The system consists of maximum of four radon detectors, optical fiber cables and a data acquisition personal computer. The radon detector uses a plastic scintillation counter that collects radon daughters in the chamber electrostatically. The applied voltage on the photocathode for the photomultiplier tube (PMT) acts as an electrode for radon daughters. The thickness of the plastic scintillator was thin, 50 /spl mu/m, so as to minimize the background counts due to the environmental gamma rays or beta particles. The energy discriminated signals from the radon detectors are fed to the data acquisition personal computer via optical fiber cables. The system made it possible to measure the radon concentrations in multiple sites simultaneously.

Applications to determine the shortest tower BTS distance using Dijkstra algorithm

NASA Astrophysics Data System (ADS)

Mardana, Herwin; Maharani, Septya; Hatta, Heliza Rahmania

2017-02-01

Telecommunications Tower or so-called BTS (Base Transceiver System) Toweris one of the main components in the network infrastructure that has experienced an increase in the number of construction. Telecommunications tower function as a place to put the antenna signal transmitter (access network) to provide communication services to customers around the tower. In addition, other use of telecommunications tower also to place the transmission signal antenna (transport network using microwave technology) for connecting customers with a central area. Therefore, in needed of a decision support system that can provide recommendations planting route of fiber optic cable with the shortest distance in purpose the use of fiber optic cable becoming more efficient. The results of the research were the shortest rule information, showing the distance to be travelled and the map view to enabling users to look at these.

Using Actively Heated Fibre Optics (AHFO) to determine soil thermal conductivity and soil moisture content at high spatial and temporal resolution

NASA Astrophysics Data System (ADS)

Ciocca, Francesco; Abesser, Corinna; Hannah, David; Blaen, Philip; Chalari, Athena; Mondanos, Michael; Krause, Stefan

2017-04-01

Optical fibre distributed temperature sensing (DTS) is increasingly used in environmental monitoring and for subsurface characterisation, e.g. to obtain precise measurements of soil temperature at high spatio-temporal resolution, over several kilometres of optical fibre cable. When combined with active heating of metal elements embedded in the optical fibre cable (active-DTS), the temperature response of the soil to heating provides valuable information from which other important soil parameters, such as thermal conductivity and soil moisture content, can be inferred. In this presentation, we report the development of an Actively Heated Fibre Optics (AHFO) method for the characterisation of soil thermal conductivity and soil moisture dynamics at high temporal and spatial resolutions at a vegetated hillslope site in central England. The study site is located within a juvenile forest adjacent to the Birmingham Institute of Forest Research (BIFoR) experimental site. It is instrumented with three loops of a 500m hybrid-optical cable installed at 10cm, 25cm and 40cm depths. Active DTS surveys were undertaken in June and October 2016, collecting soil temperature data at 0.25m intervals along the cable, prior to, during and after the 900s heating phase. Soil thermal conductivity and soil moisture were determined according to Ciocca et al. 2012, applied to both the cooling and the heating phase. Independent measurements of soil thermal conductivity and soil moisture content were collected using thermal needle probes, calibrated capacitance-based probes and laboratory methods. Results from both the active DTS survey and independent in-situ and laboratory measurements will be presented, including the observed relationship between thermal conductivity and moisture content at the study site and how it compares against theoretical curves used by the AHFO methods. The spatial variability of soil thermal conductivity and soil moisture content, as observed using the different methods, will be shown and an outlook will be provided of how the AHFO method can benefit soil sciences, ground source heat pump applications and groundwater recharge estimations. This research is part of the Distributed intelligent Heat Pulse System (DiHPS) project which is funded by the UK Natural Environmental Research Council (NERC). The project is supported by BIFoR, the European Space Agency (ESA), CarbonZero Ltd, the UK Forestry Commission and the UK Soil Moisture Observation Network (COSMOS-UK). This work is distributed under the Creative Commons Attribution 3.0 Unported Licence together with an author copyright. This licence does not conflict with the regulations of the Crown Copyright. Ciocca F., Lunati I., van de Giesen N., and Parlange M.B. 2012. Heated optical fiber for distributed soil-moisture measurements: A lysimeter experiment. Vadose Zone J. 11. doi:10.2136/vzj2011.0177

Distributed torsion sensor based on cascaded coaxial cable Fabry-Perot interferometers

NASA Astrophysics Data System (ADS)

Cheng, Baokai; Zhu, Wenge; Hua, Liwei; Liu, Jie; Li, Yurong; Nygaard, Runar; Xiao, Hai

2016-07-01

Cascaded coaxial cable Fabry-Perot interferometers (FPI) are studied and demonstrated for distributed torsion measurement. Multiple weak reflectors are implemented on a coaxial cable so that any two consecutive reflectors can form a Fabry-Perot cavity. By fixing the cable sensor in a helical form on a shaft, the distributed torsion of the shaft can be measured by the cascaded Fabry-Perot cavities. A test on a single section shows that the sensor has a linear response with a sensitivity of 1.834 MHz (rad/m)-1 in the range of twisted rate from 0 to 8.726 rad m-1. The distributed torsion sensing capability is useful in drilling process monitoring, structure health monitoring and machine failure detection.

Neuronal models in infinite-dimensional spaces and their finite-dimensional projections: Part II.

PubMed

Brzychczy, S; Leszczyński, H; Poznanski, R R

2012-09-01

Application of comparison theorem is used to examine the validitiy of the "lumped parameter assumption" in describing the behavior of solutions of the continuous cable equation U(t) = DU(xx)+f(U) with the discrete cable equation dV(n)/dt = d*(V(n+1) - 2V(n) + V(n-1)) + f(V(n)), where f is a nonlinear functional describing the internal diffusion of electrical potential in single neurons. While the discrete cable equation looks like a finite difference approximation of the continuous cable equation, solutions of the two reveal significantly different behavior which imply that the compartmental models (spiking neurons) are poor quantifiers of neurons, contrary to what is commonly accepted in computational neuroscience.

Fault-Tolerant Local-Area Network

NASA Technical Reports Server (NTRS)

Morales, Sergio; Friedman, Gary L.

1988-01-01

Local-area network (LAN) for computers prevents single-point failure from interrupting communication between nodes of network. Includes two complete cables, LAN 1 and LAN 2. Microprocessor-based slave switches link cables to network-node devices as work stations, print servers, and file servers. Slave switches respond to commands from master switch, connecting nodes to two cable networks or disconnecting them so they are completely isolated. System monitor and control computer (SMC) acts as gateway, allowing nodes on either cable to communicate with each other and ensuring that LAN 1 and LAN 2 are fully used when functioning properly. Network monitors and controls itself, automatically routes traffic for efficient use of resources, and isolates and corrects its own faults, with potential dramatic reduction in time out of service.

Fiber optic data link for data acquisition and analysis

NASA Astrophysics Data System (ADS)

Saulsberry, Garen

A data link has been designed and developed for use with fiber optics as a transmission medium, though coaxial and twisted pair cable might also be used. Multiple data types may be transferred at various rates up to 100 Mbits per second and data word width may be programmed to obtain the highest level of efficiency from the bit rate.

Silicon-etalon fiber-optic temperature sensor

NASA Technical Reports Server (NTRS)

Beheim, Glenn; Fritsch, Klaus; Flatico, Joseph M.; Azar, Massood Tabib

1989-01-01

A temperature sensor is described which consists of a silicon etalon that is sputtered directly onto the end of an optical fiber. A two-layer protective cap structure is used to improve the sensor's long-term stability. The sensor's output is wavelength encoded to provide a high degree of immunity from cable and connector effects. This sensor is extremely compact and potentially inexpensive.

Thematic mapper flight model preshipment review data package. Volume 2, part A: Subsystem data

NASA Technical Reports Server (NTRS)

1982-01-01

Performance and acceptance data are presented for the multiplexer, scan mirror, power supply, mainframe/top mechanical and the aft optics, assemblies. Other major subsystems evaluated include the relay optics, the electronic module, the radiative cooler, and the cable harness. Reference lists of nonconforming materials reports, failure reports, and requests for deviation/waiver are also given.

Vibration Performance Comparison Study on Current Fiber Optic Connector Technologies

NASA Technical Reports Server (NTRS)

Ott, Melanie N.; Thomes Jr., William J.; LaRocca, Frank V.; Switzer, Robert C.; Chuska, Rick F.; Macmurphy, Shawn L.

2008-01-01

Fiber optic cables are increasingly being used in harsh environments where they are subjected to vibration. Understanding the degradation in performance under these conditions is essential for integration of the fibers into the given application. System constraints oftentimes require fiber optic connectors so subsystems can be removed or assembled as needed. In the present work, various types of fiber optic connectors were monitored in-situ during vibration testing to examine the transient change in optical transmission and the steady-state variation following the event. Inspection of the fiber endfaces and connectors was performed at chosen intervals throughout the testing.

Optical switches and switching methods

DOEpatents

Doty, Michael

2008-03-04

A device and method for collecting subject responses, particularly during magnetic imaging experiments and testing using a method such as functional MRI. The device comprises a non-metallic input device which is coupled via fiber optic cables to a computer or other data collection device. One or more optical switches transmit the subject's responses. The input device keeps the subject's fingers comfortably aligned with the switches by partially immobilizing the forearm, wrist, and/or hand of the subject. Also a robust nonmetallic switch, particularly for use with the input device and methods for optical switching.

Note: a transimpedance amplifier for remotely located quartz tuning forks.

PubMed

Kleinbaum, Ethan; Csáthy, Gábor A

2012-12-01

The cable capacitance in cryogenic and high vacuum applications of quartz tuning forks imposes severe constraints on the bandwidth and noise performance of the measurement. We present a single stage low noise transimpedance amplifier with a bandwidth exceeding 1 MHz and provide an in-depth analysis of the dependence of the amplifier parameters on the cable capacitance.

S-net project: Construction of large scale seafloor observatory network for tsunamis and earthquakes in Japan

NASA Astrophysics Data System (ADS)

Mochizuki, M.; Kanazawa, T.; Uehira, K.; Shimbo, T.; Shiomi, K.; Kunugi, T.; Aoi, S.; Matsumoto, T.; Sekiguchi, S.; Yamamoto, N.; Takahashi, N.; Shinohara, M.; Yamada, T.

2016-12-01

National Research Institute for Earth Science and Disaster Resilience ( NIED ) has launched the project of constructing an observatory network for tsunamis and earthquakes on the seafloor. The observatory network was named "S-net, Seafloor Observation Network for Earthquakes and Tsunamis along the Japan Trench". The S-net consists of 150 seafloor observatories which are connected in line with submarine optical cables. The total length of submarine optical cable is about 5,700 km. The S-net system extends along Kuril and Japan trenches around Japan islands from north to south covering the area between southeast off island of Hokkaido and off the Boso Peninsula, Chiba Prefecture. The project has been financially supported by MEXT Japan. An observatory package is 34cm in diameter and 226cm long. Each observatory equips two units of a high sensitive water-depth sensor as a tsunami meter and four sets of three-component seismometers. The water-depth sensor has measurement resolution of sub-centimeter level. Combination of multiple seismometers secures wide dynamic range and robustness of the observation that are needed for early earthquake warning. The S-net is composed of six segment networks that consists of about 25 observatories and 800-1,600km length submarine optical cable. Five of six segment networks except the one covering the outer rise area of the Japan Trench has been already installed. The data from the observatories on those five segment networks are being transferred to the data center at NIED on a real-time basis, and then verification of data integrity are being carried out at the present moment. Installation of the last segment network of the S-net, that is, the outer rise one is scheduled to be finished within FY2016. Full-scale operation of the S-net will start at FY2017. We will report construction and operation of the S-net submarine cable system as well as the outline of the obtained data in this presentation.

Visible to Near-infrared Spectral Reflectance, NGEE-Arctic Tram, Barrow, Alaska, 2015-2017

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Ran; McMahon, Andrew; Rogers, Alistair

Canopy spectral reflectance collected from the NGEE-Arctic automated tram platform using a PP-Systems UniSpec-DC spectrometer. Downwelling radiance was measured using a 2 meter fiber optic cable connected to a cosine diffuser. Upwelling (i.e. reflected) radiance was measured using a 2 meter cable connected to a 12 degree field-of-view (FOV) lens. Canopy reflectance was calculated using the ratio of upwelling to downwelling radiance measured over a 99.99% reflectance Spectralon standard measured at the start of each measurement set.

Experimental characterization of shape memory alloy actuator cables

NASA Astrophysics Data System (ADS)

Biggs, Daniel B.; Shaw, John A.

2016-04-01

Wire rope (or cables) are a fundamental structural element in many engineering applications. Recently, there has been growing interest in stranding NiTi wires into cables to scale up the adaptive properties of NiTi tension elements and to make use of the desirable properties of wire rope. Exploratory experiments were performed to study the actuation behavior of two NiTi shape memory alloy cables and straight monofilament wire of the same material. The specimens were held under various dead loads ranging from 50 MPa to 400 MPa and thermally cycled 25 times from 140°C to 5°C at a rate of 12°C/min. Performance metrics of actuation stroke, residual strain, and work output were measured and compared between specimen types. The 7x7 cable exhibited similar actuation to the single straight wire, but with slightly longer stroke and marginally more shakedown, while maintaining equivalent specific work output. This leads to the conclusion that the 7x7 cable effectively scaled up the adaptive properties the straight wire. Under loads below 150 MPa, the 1x27 cable had up to double the actuation stroke and work output, but exhibited larger shakedown and poorer performance when loaded higher.

Vertical load capacities of roof truss cross members.

PubMed

Gearhart, David F; Morsy, Mohamed Khaled

2016-05-01

Trusses used for roof support in coal mines are constructed of two grouted bolts installed at opposing forty-five degree angles into the roof and a cross member that ties the angled bolts together. The load on the cross member is vertical, which is transverse to the longitudinal axis, and therefore the cross member is loaded in the weakest direction. Laboratory tests were conducted to determine the vertical load capacity and deflection of three different types of cross members. Single-point load tests, with the load applied in the center of the specimen and double-point load tests, with a span of 2.4 m, were conducted. For the single-point load configuration, the yield of the 25 mm solid bar cross member was nominally 98 kN of vertical load, achieved at 42 cm of deflection. For cable cross members, yield was not achieved even after 45 cm of deflection. Peak vertical loads were about 89 kN for 17 mm cables and 67 kN for the 15 mm cables. For the double-point load configurations, the 25 mm solid bar cross members yielded at 150 kN of vertical load and 25 cm of deflection. At 25 cm of deflection individual cable strands started breaking at 133 and 111 kN of vertical load for the 17 and 15 mm cable cross members respectively.

Finite element modeling of temperature load effects on the vibration of local modes in multi-cable structures

NASA Astrophysics Data System (ADS)

Treyssède, Fabien

2018-01-01

Understanding thermal effects on the vibration of local (cable-dominant) modes in multi-cable structures is a complicated task. The main difficulty lies in the modification by temperature change of cable tensions, which are then undetermined. This paper applies a finite element procedure to investigate the effects of thermal loads on the linear dynamics of prestressed self-weighted multi-cable structures. Provided that boundary conditions are carefully handled, the discretization of cables with nonlinear curved beam elements can properly represent the thermoelastic behavior of cables as well as their linearized dynamics. A three-step procedure that aims to replace applied pretension forces with displacement continuity conditions is used. Despite an increase in the computational cost related to beam rotational degrees of freedom, such an approach has several advantages. Nonlinear beam finite elements are usually available in commercial codes. The overall method follows a thermoelastic geometrically non-linear analysis and hereby includes the main sources of non-linearities in multi-cable structures. The effects of cable bending stiffness, which can be significant, are also naturally accounted for. The accuracy of the numerical approach is assessed thanks to an analytical model for the vibration of a single inclined cable under temperature change. Then, the effects of thermal loads are investigated for two cable bridges, highlighting how natural frequencies can be affected by temperature. Although counterintuitive, a reverse relative change of natural frequency may occur for certain local modes. This phenomenon can be explained by two distinct mechanisms, one related to the physics intrinsic to cables and the other related to the thermal deflection of the superstructure. Numerical results show that cables cannot be isolated from the rest of the structure and the importance of modeling the whole structure for a quantitative analysis of temperature effects on the dynamics of cable bridges.

ARINC 818 express for high-speed avionics video and power over coax

NASA Astrophysics Data System (ADS)

Keller, Tim; Alexander, Jon

2012-06-01

CoaXPress is a new standard for high-speed video over coax cabling developed for the machine vision industry. CoaXPress includes both a physical layer and a video protocol. The physical layer has desirable features for aerospace and defense applications: it allows 3Gbps (up to 6Gbps) communication, includes 21Mbps return path allowing for bidirectional communication, and provides up to 13W of power, all over a single coax connection. ARINC 818, titled "Avionics Digital Video Bus" is a protocol standard developed specifically for high speed, mission critical aerospace video systems. ARINC 818 is being widely adopted for new military and commercial display and sensor applications. The ARINC 818 protocol combined with the CoaXPress physical layer provide desirable characteristics for many aerospace systems. This paper presents the results of a technology demonstration program to marry the physical layer from CoaXPress with the ARINC 818 protocol. ARINC 818 is a protocol, not a physical layer. Typically, ARINC 818 is implemented over fiber or copper for speeds of 1 to 2Gbps, but beyond 2Gbps, it has been implemented exclusively over fiber optic links. In many rugged applications, a copper interface is still desired, by implementing ARINC 818 over the CoaXPress physical layer, it provides a path to 3 and 6 Gbps copper interfaces for ARINC 818. Results of the successful technology demonstration dubbed ARINC 818 Express are presented showing 3Gbps communication while powering a remote module over a single coax cable. The paper concludes with suggested next steps for bring this technology to production readiness.

Decoy-state quantum key distribution with polarized photons over 200 km.

PubMed

Liu, Yang; Chen, Teng-Yun; Wang, Jian; Cai, Wen-Qi; Wan, Xu; Chen, Luo-Kan; Wang, Jin-Hong; Liu, Shu-Bin; Liang, Hao; Yang, Lin; Peng, Cheng-Zhi; Chen, Kai; Chen, Zeng-Bing; Pan, Jian-Wei

2010-04-12

We report an implementation of decoy-state quantum key distribution (QKD) over 200 km optical fiber cable through photon polarization encoding. This is achieved by constructing the whole QKD system operating at 320 MHz repetition rate, and developing high-speed transmitter and receiver modules. A novel and economic way of synchronization method is designed and incorporated into the system, which allows to work at a low frequency of 40kHz and removes the use of highly precise clock. A final key rate of 15 Hz is distributed within the experimental time of 3089 seconds, by using super-conducting single photon detectors. This is longest decoy-state QKD yet demonstrated up to date. It helps to make a significant step towards practical secure communication in long-distance scope.

Demonstration of an advanced fibre laser hydrophone array in Gulf St Vincent

NASA Astrophysics Data System (ADS)

Foster, Scott; Tikhomirov, Alexei; Harrison, Joanne; van Velzen, John

2015-09-01

We have developed an 8-element fibre laser seabed array demonstrating state-of-the art performance characteristics for a fibre laser sensing system. The system employs sea-state-zero sensitivity hydrophones with a flat acoustic response over a bandwidth exceeding 5kHz and very low inertial sensitivity. The system contains no outboard electronics and few metal components making it extremely light, compact, and low complexity. The array may be deployed up to 4 km from a land or sea based platform to a depth of up to 80m. Power delivery and telemetry for all 8 sensors is achieved via a single 2mm diameter optical fibre cable weighing less than 5kg per km. We report here results of the first field trials of this system.

Irrigation scheduling of green areas based on soil moisture estimation by the active heated fiber optic distributed temperature sensing AHFO

NASA Astrophysics Data System (ADS)

Zubelzu, Sergio; Rodriguez-Sinobas, Leonor; Sobrino, Fernando; Sánchez, Raúl

2017-04-01

Irrigation programing determines when and how much water apply to fulfill the plant water requirements depending of its phenology stage and location, and soil water content. Thus, the amount of water, the irrigation time and the irrigation frequency are variables that must be estimated. Likewise, irrigation programing has been based in approaches such as: the determination of plant evapotranspiration and the maintenance of soil water status between a given interval or soil matrix potential. Most of these approaches are based on the measurements of soil water sensors (or tensiometers) located at specific points within the study area which lack of the spatial information of the monitor variable. The information provided in such as few points might not be adequate to characterize the soil water distribution in irrigation systems with poor water application uniformity and thus, it would lead to wrong decisions in irrigation scheduling. Nevertheless, it can be overcome if the active heating pulses distributed fiber optic temperature measurement (AHFO) is used. This estimates the temperature variation along a cable of fiber optic and then, it is correlated with the soil water content. This method applies a known amount of heat to the soil and monitors the temperature evolution, which mainly depends on the soil moisture content. Thus, it allows estimations of soil water content every 12.5 cm along the fiber optic cable, as long as 1500 m (with 2 % accuracy) , every second. This study presents the results obtained in a green area located at the ETSI Agronómica, Agroalimentaria y Biosistesmas in Madrid. The area is irrigated by an sprinkler irrigation system which applies water with low uniformity. Also, it has deployed and installation of 147 m of fiber optic cable at 15 cm depth. The Distribute Temperature Sensing unit was a SILIXA ULTIMA SR (Silixa Ltd, UK) with spatial and temporal resolution of 0.29 m and 1 s, respectively. In this study, heat pulses of 7 W/m for 2 min were applied uniformly along the fiber optic cable and the thermal response on an adjacent cable was monitored prior, during and after the irrigation event. Data was logged every 0.3 m and every 5 s then, the heating and drying phase integer (called Tcum) was determined following the approach of Sayde et al., (2010). Thus, the infiltration and redistribution of soil water content was fully characterized. The results are promising since the water spatial variability within the soil is known and it can be correlated with the water distribution in the irrigation unit to make better irrigation scheduling in the green area improving water/nutrient/energy efficiency.. Reference Létourneau, G., Caron, J., Anderson, L., & Cormier, J. (2015). Matric potential-based irrigation management of field-grown strawberry: Effects on yield and water use efficiency. Agricultural Water Management, 161, 102-113. Liang, X., Liakos, V., Wendroth, O., & Vellidis, G. (2016). Scheduling irrigation using an approach based on the van Genuchten model. Agricultural Water Management, 176, 170-179. Sayde,C., Gregory, C., Gil-Rodriguez, M., Tufillaro, N., Tyler, S., van de Giesen, N., English, M. Cuenca, R. and Selker, J. S.. 2010. Feasibility of soil moisture monitoring with heated fiber optics. Water Resources Research. Vol.46 (6). DOI: 10.1029/2009WR007846 Stirzaker, R. J., Maeko, T. C., Annandale, J. G., Steyn, J. M., Adhanom, G. T., & Mpuisang, T. (2017). Scheduling irrigation from wetting front depth. Agricultural Water Management, 179, 306-313.

Measurement of the Minority Carrier Diffusion Rate in N-GaAs.

DTIC Science & Technology

1980-12-01

allow insertion of a fiber -optic cable. This fiber -optic link was necessary to permit a reference signal to impinge upon the photo- multiplier for some...lens onto the entrance slit of the spectrometer. The spectrometer is coupled by means of a light-tight coupler to the photomultiplier, and a fiber ...optic light path is provided to allow a reference 2 ’i29 1 "-I Laser Doubler - 1.06 Filters Pellicle Photomultiplier 0Spectrometer Lens/ Fiber RG-715

Neural Network Grasping Controller for Continuum Robots

DTIC Science & Technology

2006-01-01

string encoders attached to the base of section 1 and optical encoders located at the end plates of section 1 and 2. The cables from each of the...string encoders run the entire length of the arm through the optical encoders at the lower sections, as seen in Figure 1. This configuration enables the...encoders at the base section and the optical encoders at the end plates of the distal sections, there were a number of protrusions on the surface of the arm

Optical amplification at the 1. 31 wavelength

DOEpatents

Cockroft, N.J.

1994-02-15

An optical amplifier operating at the 1.31 [mu]m wavelength for use in such applications as telecommunications, cable television, and computer systems is described. An optical fiber or other waveguide device is doped with both Tm[sup 3+] and Pr[sup 3+] ions. When pumped by a diode laser operating at a wavelength of 785 nm, energy is transferred from the Tm[sup 3+] ions to the Pr[sup 3+] ions, causing the Pr[sup 3+] ions to amplify at a wavelength of 1.31. 1 figure.

Optical amplification at the 1.31 wavelength

DOEpatents

Cockroft, Nigel J.

1994-01-01

An optical amplifier operating at the 1.31 .mu.m wavelength for use in such applications as telecommunications, cable television, and computer systems. An optical fiber or other waveguide device is doped with both Tm.sup.3+ and Pr.sup.3+ ions. When pumped by a diode laser operating at a wavelength of 785 nm, energy is transferred from the Tm.sup.3+ ions to the Pr.sup.3+ ions, causing the Pr.sup.3+ ions to amplify at a wavelength of 1.31

Localizing Fracture Hydromechanical Response using Fiber Optic Distributed Acoustic Sensing in a Fractured Bedock Aquifer

NASA Astrophysics Data System (ADS)

Chevrot, S.; Wang, Y.; Monteiller, V.; Komatitsch, D.; Martin, R.

2016-12-01

Measuring fracture mechanical behavior in response to changes in fluid pressure is critical for understanding flow through petroleum reservoirs, predicting hydrothermal responses in geothermal fields, and monitoring geologic carbon sequestration injection. Distributed acoustic sensing (DAS) is new, but commercially available fiber optic technology that offers a novel approach to characterize fractured bedrock systems. DAS was originally designed to measure the amplitude, frequency, and phase of an acoustic wave, and is therefore capable of detecting strains at exceedingly small scales. Though normally used to measure frequencies in the Hz to kHz range, we adapted DAS to measure fracture displacements in response to periodic hydraulic pulses in the mHz frequency range. A field experiment was conducted in a fractured bedrock aquifer to test the ability of DAS to measure fracture mechanical response to oscillatory well tests. Fiber optic cable was deployed in a well, and coupled to the borehole wall using a flexible impermeable liner designed with an air coupled transducer to measure fluid pressure at the target fracture zone. Two types of cable were tested, a loose tube and tight buffered, to determine the effects of cable construction. Both strain and pressure were measured across the known fracture zone hydraulically connected to a well 30 m away. The companion well was subjected to alternating pumping and injection with periods between 2 and 18 minutes. Raw DAS data were collected as strain rate measured every 0.25 m along the fiber with a gauge length of 10 m, at a sampling rate of 1 kHz. Strain rate was converted to strain by integrating with respect to time. DAS measured periodic strains of less than 1 nm/m in response to periodic injection and pumping at the companion well. Strain was observed by DAS only at the depth of the hydraulically connected fracture zone. Thus, the magnitude and response of the strain could be both localized with depth and measured quantitatively. The tight buffered cable was found to be twice as sensitive to strain than the loose tube cable construction. This technology holds promise for monitoring mechanical strain in response to periodic hydraulic testing. Such an approach could be used, for example, in leak detection of injection systems by inducing a periodically varying injection rate.

Feasibility of leakage detection in lake pressure pipes using the Distributed Temperature Sensing Technology

NASA Astrophysics Data System (ADS)

Apperl, Benjamin; Pressl, Alexander; Schulz, Karsten

2016-04-01

This contribution describes a feasibility study carried out in the laboratory for the detection of leakages in lake pressure pipes using high-resolution fiber-optic temperature measurements (DTS). The usage of the DTS technology provides spatiotemporal high-resolution temperature measurements along a fibre optic cable. An opto-electrical device serves both as a light emitter as well as a spectrometer for measuring the scattering of light. The fiber optic cable serves as linear sensor. Measurements can be taken at a spatial resolution of up to 25 cm with a temperature accuracy of higher than 0.1 °C. The first warmer days after the winter stagnation provoke a temperature rise of superficial layers of lakes with barely stable temperature stratification. The warmer layer in the epilimnion differs 4 °C to 5 °C compared to the cold layers in the meta- or hypolimnion before water circulation in spring starts. The warmer water from the surface layer can be rinsed on the entire length of the pipe. Water intrudes at leakages by generating a slightly negative pressure in the pipe. This provokes a local temperature change, in case that the penetrating water (seawater) differs in temperature from the water pumped through the pipe. These temperature changes should be detectable and localized with a DTS cable introduced in the pipe. A laboratory experiment was carried out to determine feasibility as well as limits and problems of this methodology. A 6 m long pipe, submerged in a water tank at constant temperature, was rinsed with water 5-10 °C warmer than the water in the tank. Temperature measurements were taken continuously along the pipe. A negative pressure of 0.1 bar provoked the intrusion of colder water from the tank into the pipe through the leakages, resulting in local temperature changes. Experiments where conducted with different temperature gradients, leakage sizes, number of leaks as well as with different positioning of the DTS cable inside the pipe. Results showed that already small leakages (4mm) can be detected. Problems have arisen from the inside positioning of DTS cable, measuring a reduced temperature difference in the transition layer at the inside wall of the pipe.

Localizing Fracture Hydromechanical Response using Fiber Optic Distributed Acoustic Sensing in a Fractured Bedock Aquifer

NASA Astrophysics Data System (ADS)

Ciervo, C.; Becker, M.; Cole, M. C.; Coleman, T.; Mondanos, M.

2017-12-01

Measuring fracture mechanical behavior in response to changes in fluid pressure is critical for understanding flow through petroleum reservoirs, predicting hydrothermal responses in geothermal fields, and monitoring geologic carbon sequestration injection. Distributed acoustic sensing (DAS) is new, but commercially available fiber optic technology that offers a novel approach to characterize fractured bedrock systems. DAS was originally designed to measure the amplitude, frequency, and phase of an acoustic wave, and is therefore capable of detecting strains at exceedingly small scales. Though normally used to measure frequencies in the Hz to kHz range, we adapted DAS to measure fracture displacements in response to periodic hydraulic pulses in the mHz frequency range. A field experiment was conducted in a fractured bedrock aquifer to test the ability of DAS to measure fracture mechanical response to oscillatory well tests. Fiber optic cable was deployed in a well, and coupled to the borehole wall using a flexible impermeable liner designed with an air coupled transducer to measure fluid pressure at the target fracture zone. Two types of cable were tested, a loose tube and tight buffered, to determine the effects of cable construction. Both strain and pressure were measured across the known fracture zone hydraulically connected to a well 30 m away. The companion well was subjected to alternating pumping and injection with periods between 2 and 18 minutes. Raw DAS data were collected as strain rate measured every 0.25 m along the fiber with a gauge length of 10 m, at a sampling rate of 1 kHz. Strain rate was converted to strain by integrating with respect to time. DAS measured periodic strains of less than 1 nm/m in response to periodic injection and pumping at the companion well. Strain was observed by DAS only at the depth of the hydraulically connected fracture zone. Thus, the magnitude and response of the strain could be both localized with depth and measured quantitatively. The tight buffered cable was found to be twice as sensitive to strain than the loose tube cable construction. This technology holds promise for monitoring mechanical strain in response to periodic hydraulic testing. Such an approach could be used, for example, in leak detection of injection systems by inducing a periodically varying injection rate.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zediker, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.

There is provided a system and apparatus for the transmission of high power laser energy over great distances without substantial power loss and without the presence of stimulated Raman scattering. There is further provided systems and optical fiber cable configurations and optical fiber structures for the delivering high power laser energy over great distances to a tool or surface to perform an operation or work with the tool or upon the surface.

Photogrammetric Verification of Fiber Optic Shape Sensors on Flexible Aerospace Structures

NASA Technical Reports Server (NTRS)

Moore, Jason P.; Rogge, Matthew D.; Jones, Thomas W.

2012-01-01

Multi-core fiber (MCF) optic shape sensing offers the possibility of providing in-flight shape measurements of highly flexible aerospace structures and control surfaces for such purposes as gust load alleviation, flutter suppression, general flight control and structural health monitoring. Photogrammetric measurements of surface mounted MCF shape sensing cable can be used to quantify the MCF installation path and verify measurement methods.

Distributed measurement of high electric current by means of polarimetric optical fiber sensor.

PubMed

Palmieri, Luca; Sarchi, Davide; Galtarossa, Andrea

2015-05-04

A novel distributed optical fiber sensor for spatially resolved monitoring of high direct electric current is proposed and analyzed. The sensor exploits Faraday rotation and is based on the polarization analysis of the Rayleigh backscattered light. Preliminary laboratory tests, performed on a section of electric cable for currents up to 2.5 kA, have confirmed the viability of the method.

Properties of plastic tapes for cryogenic power cable insulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muller, A C

1978-01-01

A superconducting ac power transmission cable is under development at Brookhaven National Laboratory (BNL). This project was undertaken in 1972 in response to growing national power requirements. The goal of this program is to develop an underground power transmission system suitable for transferring bulk quantities of electricity over distances of 16 to 160 km. Both the capital investment and operating costs must be low enough to make the system attractive to the electric utilities. The superconducting cable shares the advantages with conventional underground cables of needing only a few feet of right-of-way width rather than the large tracts of increasinglymore » expensive land required for conventional aerial transmission. Recent cost analysis studies show that superconducting cables, although more expensive than aerial transmission, will probably be competitive with other methods of underground transmission at loads greater than 2000 MVA. Initial design studies showed that a flexible, forced-cooled cable offered the best combination of technical and economic features. A helium cooled cable with Nb/sub 3/Sn superconductor was chosen as the BNL design. The present goal of the BNL program is the construction of a 100 meter outdoor three-phase ac cable rated at 138 kV and 1000 MVA. The refrigerator and the 100 m-long dewar are already installed. Terminations and cables are under design, and it is planned to begin installation of the first single phase cable in 1979. If the results on this model show promise for eventual commercial use, cables of higher voltage and power rating will be developed. One fundamental phase of this project; the development of the required insulating materials, is described.« less

Roebel cables from REBCO coated conductors: a one-century-old concept for the superconductivity of the future

NASA Astrophysics Data System (ADS)

Goldacker, Wilfried; Grilli, Francesco; Pardo, Enric; Kario, Anna; Schlachter, Sonja I.; Vojenčiak, Michal

2014-09-01

Energy applications employing high-temperature superconductors (HTS), such as motors/generators, transformers, transmission lines and fault current limiters, are usually operated in the alternate current (ac) regime. In order to be efficient, the HTS devices need to have a sufficiently low value of ac loss, in addition to the necessary current-carrying capacity. Most applications are operated with currents beyond the current capacity of single conductors and consequently require cabled conductor solutions with much higher current carrying capacity, from a few kA up to 20-30 kA for large hydro-generators. A century ago, in 1914, Ludwig Roebel invented a low-loss cable design for copper cables, which was successively named after him. The main idea behind Roebel cables is to separate the current in different strands and to provide a full transposition of the strands along the cable direction. Nowadays, these cables are commonly used in the stator of large generators. Based on the same design concept of their conventional material counterparts, HTS Roebel cables from REBCO coated conductors were first manufactured at the Karlsruhe Institute of Technology and have been successively developed in a number of varieties that provide all the required technical features such as fully transposed strands, high transport currents and low ac losses, yet retaining enough flexibility for a specific cable design. In the past few years a large number of scientific papers have been published on the concept, manufacturing and characterization of such cables. Therefore it is timely for a review of those results. The goal is to provide an overview and a succinct and easy-to-consult guide for users, developers, and manufacturers of this kind of HTS cable.

Challenges in Locating Microseismic Events Using Distributed Acoustic Sensors

NASA Astrophysics Data System (ADS)

Williams, A.; Kendall, J. M.; Clarke, A.; Verdon, J.

2017-12-01

Microseismic monitoring is an important method of assessing the behaviour of subsurface fluid processes, and is commonly acquired using geophone arrays in boreholes or on the surface. A new alternative technology has been recently developed - fibre-optic Distributed Acoustic Sensing (DAS) - using strain along a fibre-optic cable as a measure of seismic signals. DAS can offer high density arrays and full-well coverage from the surface to bottom, with less overall disruption to operations, so there are many exciting possible applications in monitoring both petroleum and other subsurface industries. However, there are challenges in locating microseismic events recorded using current DAS systems, which only record seismic data in one-component and consequently omit the azimuthal information provided by a three-component geophone. To test the impact of these limitations we used finite difference modelling to generate one-component synthetic DAS datasets and investigated the impact of picking solely P-wave or both P- and S-wave arrivals and the impact of different array geometries. These are then compared to equivalent 3-component synthetic geophone datasets. In simple velocity models, P-wave arrivals along linear arrays cannot be used to constrain locations using DAS, without further a priori information. We then tested the impact of straight cables vs. L-shaped arrays and found improved locations when the cable is deviated, especially when both P- and S-wave picks are included. There is a trade-off between the added coverage of DAS cables versus sparser 3C geophone arrays where particle motion helps constrains locations, which cannot be assessed without forward modelling.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, D.E.; Roeske, F.

We have successfully fielded a Fiber Optics Radiation Experiment system (FOREX) designed for measuring material properties at high temperatures and pressures in an underground nuclear test. The system collects light from radiating materials and transmits it through several hundred meters of optical fibers to a recording station consisting of a streak camera with film readout. The use of fiber optics provides a faster time response than can presently be obtained with equalized coaxial cables over comparable distances. Fibers also have significant cost and physical size advantages over coax cables. The streak camera achieves a much higher information density than anmore » equivalent oscilloscope system, and it also serves as the light detector. The result is a wide bandwidth high capacity system that can be fielded at a relatively low cost in manpower, space, and materials. For this experiment, the streak camera had a 120 ns time window with a 1.2 ns time resolution. Dynamic range for the system was about 1000. Beam current statistical limitations were approximately 8% for a 0.3 ns wide data point at one decade above the threshold recording intensity.« less

The other fiber, the other fabric, the other way

NASA Astrophysics Data System (ADS)

Stephens, Gary R.

1993-02-01

Coaxial cable and distributed switches provide a way to configure high-speed Fiber Channel fabrics. This type of fabric provides a cost-effective alternative to a fabric of optical fibers and centralized cross-point switches. The fabric topology is a simple tree. Products using parallel busses require a significant change to migrate to a serial bus. Coaxial cables and distributed switches require a smaller technology shift for these device manufacturers. Each distributed switch permits both medium type and speed changes. The fabric can grow and bridge to optical fibers as the needs expand. A distributed fabric permits earlier entry into high-speed serial operations. For very low-cost fabrics, a distributed switch may permit a link configured as a loop. The loop eliminates half of the ports when compared to a switched point-to-point fabric. A fabric of distributed switches can interface to a cross-point switch fabric. The expected sequence of migration is: closed loops, small closed fabrics, and, finally, bridges, to connect optical cross-point switch fabrics. This paper presents the concept of distributed fabrics, including address assignment, frame routing, and general operation.

Improving greater trochanteric reattachment with a novel cable plate system.

PubMed

Baril, Yannick; Bourgeois, Yan; Brailovski, Vladimir; Duke, Kajsa; Laflamme, G Yves; Petit, Yvan

2013-03-01

Cable-grip systems are commonly used for greater trochanteric reattachment because they have provided the best fixation performance to date, even though they have a rather high complication rate. A novel reattachment system is proposed with the aim of improving fixation stability. It consists of a Y-shaped fixation plate combined with locking screws and superelastic cables to reduce cable loosening and limit greater trochanter movement. The novel system is compared with a commercially available reattachment system in terms of greater trochanter movement and cable tensions under different greater trochanteric abductor application angles. A factorial design of experiments was used including four independent variables: plate system, cable type, abductor application angle, and femur model. The test procedure included 50 cycles of simultaneous application of an abductor force on the greater trochanter and a hip force on the femoral head. The novel plate reduces the movements of a greater trochanter fragment within a single loading cycle up to 26%. Permanent degradation of the fixation (accumulated movement based on 50-cycle testing) is reduced up to 46%. The use of superelastic cables reduces tension loosening up to 24%. However this last improvement did not result in a significant reduction of the grater trochanter movement. The novel plate and cables present advantages over the commercially available greater trochanter reattachment system. The plate reduces movements generated by the hip abductor. The superelastic cables reduce cable loosening during cycling. Both of these positive effects could decrease the risks related to grater trochanter non-union. Copyright © 2012 IPEM. Published by Elsevier Ltd. All rights reserved.

Innovative and effective techniques for locating underground conduits.

DOT National Transportation Integrated Search

2011-06-01

The New Jersey Department of Transportation (NJDOT) operates and maintains a network of : thousands of miles of conduits, many carrying fiber optic cables, that is vital to the States : communication system. These conduits frequently must be locat...

7 CFR 1755.200 - RUS standard for splicing copper and fiber optic cables.

Code of Federal Regulations, 2013 CFR

2013-01-01

.../code_of_federal_regulations/ibr_locations.html. Copies are available from NFPA, Batterymarch Park..., depending on the site logistics. However, the required slack is seldom less than 15 meters (50 feet). The...

7 CFR 1755.200 - RUS standard for splicing copper and fiber optic cables.

Code of Federal Regulations, 2014 CFR

2014-01-01

.../code_of_federal_regulations/ibr_locations.html. Copies are available from NFPA, Batterymarch Park..., depending on the site logistics. However, the required slack is seldom less than 15 meters (50 feet). The...

7 CFR 1755.200 - RUS standard for splicing copper and fiber optic cables.

Code of Federal Regulations, 2012 CFR

2012-01-01

.../code_of_federal_regulations/ibr_locations.html. Copies are available from NFPA, Batterymarch Park..., depending on the site logistics. However, the required slack is seldom less than 15 meters (50 feet). The...

Using DAS for reflection seismology - lessons learned from three field studies

NASA Astrophysics Data System (ADS)

Freifeld, B. M.; Dou, S.; Ajo Franklin, J. B.; Robertson, M.; Wood, T.; Daley, T. M.; White, D. J.; Worth, K.; Pevzner, R.; Yavuz, S.; dos Santos Maia Correa, J.; McDonald, S.

2017-12-01

Distributed acoustic sensing (DAS) has rapidly gained recognition for its potential for seismic imaging. For surface reflection seismology, the wide spatial aperture afforded by DAS is a primary motivation for its application, however the lower SNR of DAS has proven to be a significant impediment to acquiring data that can replace conventional receiver arrays. A further limitation of DAS cables is that the strain-dependent response is insensitive to acoustic energy which arrives orthogonal to the cable axis, reducing its effectiveness at seeing energy reflected from the deep subsurface. To enhance the sensitivity of DAS cables for reflection seismology, we have trialed at three field sites DAS cables with helical construction in which there is a significant component of optical fiber that is coincident with arriving broadside energy. We have installed helically wound DAS cables at the PTRC Aquistore Project in Saskatchewan, Canada and the CO2CRC Otway Project in Nirranda South, Victoria, Australia in shallow trenches. For the ADM Intelligent Monitoring Systems Project in Decatur, Illinois, USA we used a horizontal directional drilling method to install DAS cables at a depth that is greater than can be achieved using trenched installation. At the Otway and ADM sites we operated surface orbital vibrators (SOVs) at fixed locations to enhance sensitivity by stacking large numbers of sweeps. We present survey results from the three sites. Analysis of both vibroseis survey and SOV results show that the helical cable design achieves its primary objective of improving sensitivity to reflected energy, with further gains needed to achieve the sensitivity of conventional geophones.

Thermal profiles for reaches of Snee-Oosh and Fornsby Creeks, Swinomish Indian Reservation, northwestern Washington, July 2013

USGS Publications Warehouse

Gendaszek, Andrew S.; Opatz, Chad C.

2013-01-01

Longitudinal profiles of streambed temperatures were measured in approximately 225-m-long reaches of the Snee-Oosh and Fornsby Creeks in the Swinomish Indian Reservation, northwestern Washington, during July 2013, to provide information about areas of groundwater discharge to streams. During summer, groundwater discharge is a source of cold water to streams and typically cools the surface water into which it discharges and buffers diurnal temperature fluctuations. Near-streambed temperatures were averaged over 1-m-long sections of cable during 1-minute periods every 30 minutes for 1-week periods using a fiber-optic distributed temperature sensor positioned on top of the streambed. The position of the fiber-optic cable was surveyed with a Global Positioning System. Stream temperatures and survey data are presented as Microsoft Excel® files consisting of date and time, water temperature, and geographical coordinates.

Analysis of existing data from a Distributed Acoustic Sensing experiment at Garner Valley, California using noise correlation functions (PoroTomo Substask 3.2)

DOE Data Explorer

Zeng, Xiangfang

2015-03-26

In September 2013, an experiment using Distributed Acoustic Sensing (DAS) was conducted at Garner Valley, a test site of the University of California Santa Barbara (Lancelle et al., 2014). This submission includes noise cross-correlation functions (NCF) . Each file includes a NCF between two channels. The name of each channel denotes the distance in meters from starting point of the fiber-optic cable. Lancelle, C., N. Lord, H. Wang, D. Fratta, R. Nigbor, A. Chalari, R. Karaulanov, J. Baldwin, and E. Castongia (2014), Directivity and Sensitivity of Fiber-Optic Cable Measuring Ground Motion using a Distributed Acoustic Sensing Array (abstract # NS31C-3935), AGU Fall Meeting. https://agu.confex.com/agu/fm14/meetingapp.cgi#Paper/19828 The e-poster is available at: https://agu.confex.com/data/handout/agu/fm14/Paper_19828_handout_696_0.pdf

Microminiaturized minimally invasive intravascular micro-mechanical systems powered and controlled via fiber-optic cable

DOEpatents

Fitch, Joseph P.; Hagans, Karla; Clough, Robert; Matthews, Dennis L.; Lee, Abraham P.; Krulevitch, Peter A.; Benett, William J.; Da Silva, Luiz; Celliers, Peter M.

1998-01-01

A micro-mechanical system for medical procedures is constructed in the basic form of a catheter having a distal end for insertion into and manipulation within a body and a near end providing for a user to control the manipulation of the distal end within the body. A fiberoptic cable is disposed within the catheter and having a distal end proximate to the distal end of the catheter and a near end for external coupling of laser light energy. A microgripper is attached to the distal end of the catheter and providing for the gripping or releasing of an object within the body. A laser-light-to-mechanical-power converter is connected to receive laser light from the distal end of the fiberoptic cable and connected to mechanically actuate the microgripper.

Optical Inspection In Hostile Industrial Environments: Single-Sensor VS. Imaging Methods

NASA Astrophysics Data System (ADS)

Cielo, P.; Dufour, M.; Sokalski, A.

1988-11-01

On-line and unsupervised industrial inspection for quality control and process monitoring is increasingly required in the modern automated factory. Optical techniques are particularly well suited to industrial inspection in hostile environments because of their noncontact nature, fast response time and imaging capabilities. Optical sensors can be used for remote inspection of high temperature products or otherwise inaccessible parts, provided they are in a line-of-sight relation with the sensor. Moreover, optical sensors are much easier to adapt to a variety of part shapes, position or orientation and conveyor speeds as compared to contact-based sensors. This is an important requirement in a flexible automation environment. A number of choices are possible in the design of optical inspection systems. General-purpose two-dimensional (2-D) or three-dimensional (3-D) imaging techniques have advanced very rapidly in the last years thanks to a substantial research effort as well as to the availability of increasingly powerful and affordable hardware and software. Imaging can be realized using 2-D arrays or simpler one-dimensional (1-D) line-array detectors. Alternatively, dedicated single-spot sensors require a smaller amount of data processing and often lead to robust sensors which are particularly appropriate to on-line operation in hostile industrial environments. Many specialists now feel that dedicated sensors or clusters of sensors are often more effective for specific industrial automation and control tasks, at least in the short run. This paper will discuss optomechanical and electro-optical choices with reference to the design of a number of on-line inspection sensors which have been recently developed at our institute. Case studies will include real-time surface roughness evaluation on polymer cables extruded at high speed, surface characterization of hot-rolled or galvanized-steel sheets, temperature evaluation and pinhole detection in aluminum foil, multi-wavelength polymer sheet thickness gauging and thermographic imaging, 3-D lumber profiling, line-array inspection of textiles and glassware, as well as on-line optical inspection for the control of automated arc welding. In each case the design choices between single or multiple-element detectors, mechanical vs. electronic scanning, laser vs. incoherent illumination, etc. will be discussed in terms of industrial constraints such as speed requirements, protection against the environment or reliability of the sensor output.

The Lighthouse Ocean Research Initiative: Sustained Cabled Ocean Observing Systems in the Sea of Oman and Arabian Sea

NASA Astrophysics Data System (ADS)

Ingle, S.; Du Vall, K.; Dimarco, S. F.

2011-12-01

In 2003 Lighthouse R & D Enterprises, Inc. began developing an ocean observing system that would help the Sultanate of Oman better manage the health of their fisheries. The resulting cutting-edge, fiber-optic cabled ocean observatory was installed in the northern Sea of Oman and became operational in August of 2005; this summer the system surpassed the milestone of 2100 days of successful operation. A second, deepwater cabled observatory was installed farther to the south, where the Sea of Oman meets the Arabian Sea, in January, 2010. Both systems monitor physical properties throughout the water column including current velocity, temperature, pressure, conductivity, dissolved oxygen and turbidity. The entirely subsea nature of the fiber-optic cabled observatory capitalizes on several advantages over traditional buoyed systems including a lack of exposure to environmental wear and tear, collision, vandalism and theft. The systems are both cabled to nearby shore facilities, where the data are relayed instantly to Houston via satellite for processing, analysis and modeling - the data may also be used in making real time decisions. Many challenges were encountered between the design / development stage and the operation a reliable, long-term, real-time observing system in a dynamic marine environment. Examples of obstacles we encountered and overcame include: maintaining upright mooring strings under differential current velocities; minimizing points of weakness in the system, especially the number of wet mates; recognizing the need for cathodic protection in unanticipated places; protecting vulnerable sensors from biofouling; developing a climate-controlled shore facility in a harsh and remote environment; ensuring an uninterrupted power supply and availability of additional power bursts when required; and lengthening the life of the system while reducing the need for maintenance. The design and obstacles and scientific questions being addressed by the Lighthouse systems will be covered in this presentation.

Optical Telemetry Improves Persistence and Data Access at Woolsey Mound Observatory, Mississippi Canyon block 118, Gulf of Mexico

NASA Astrophysics Data System (ADS)

Farr, N.; Sleeper, K.; Camilli, R.; Pontbriand, C.; Ware, J.

2011-12-01

A suite of geochemical arrays have been developed for the Woolsey Mound Seafloor Observatory in the northern Gulf of Mexico to evaluate the oceanographic and tectonic forcing factors on the formation and stability of gas hydrate. These arrays are designed to collect sustained, time-series data of chemical concentrations, gradients and flux from the subsurface to the sea floor and into the near bottom water column. A key component of the Observatory is the Benthic Boundary Layer Array (BBLA). The BBLA has two sensor nodes, one near the seafloor and the other 20m above the bottom. Each node has a suite of instruments to collect physical and chemical measurements (O2, T, P, S, pH, ORP, CDOM, Chly-A, and aromatic HC). The array provides a time-series data set, twenty seconds out of every 5 minutes, for evaluating the fate of transiting fluids form the seafloor and on downward, cross, or up welling conditions that are associated with a hydrate destabilization event. We report on the successes of multiple deployments of the BBLA and on the integration of a new underwater optical communication system that provides high data rate communications over a range of >100 meters from a subsurface mooring. Optical communications is capable of high data rates, up to 10 mega bits per second (Mbps), compared to acoustic data rates of 5 Kbps. We have developed an integrated optical/acoustic telemetry system (OTS) that uses an acoustic command system to control a high bandwidth, low latency optical communication system. In June 2011, from the RV Pelican, we deployed the BBLA, which included an inline, mooring mounted, optical modem. Using a lowered OTS mounted on a frame with batteries, and a fiber optic connection to the surface,the OTS was lowered by wire from a surface ship. An optical communication link was established, with a range of >100 meters, and a transmission rate of 2.5 Mbps, which provided successful file transfers. The OTS/BBLA will remain installed at MC118 for one year, at which point it will be visited to offload data prior to recovery. The OTS permits non submersible equipped surface vessels to interrogate the BBLA hydrates observatory on a more frequent basis using a receiver lowered by wire from a ship of opportunity. In the future, autonomous vehicles could interrogate such seafloor observatories in a "data-mule" configuration and then dock at a seafloor cabled node or return to the vehicle deployment site to offload data. This technology offers immediate opportunities for persistent seafloor observatories where cabling to shore is either impractical or not available yet. While MC118 may ultimately be linked into undersea cables, relaying real-time data back to shore, there is a superb opportunity to test free water optical communication methods for intermediate time frame data offload, and to install a persistent observatory now, prior to installing a cable, which may take years to complete.

Fiber optic cable-based high-resolution, long-distance VGA extenders

NASA Astrophysics Data System (ADS)

Rhee, Jin-Geun; Lee, Iksoo; Kim, Heejoon; Kim, Sungjoon; Koh, Yeon-Wan; Kim, Hoik; Lim, Jiseok; Kim, Chur; Kim, Jungwon

2013-02-01

Remote transfer of high-resolution video information finds more applications in detached display applications for large facilities such as theaters, sports complex, airports, and security facilities. Active optical cables (AOCs) provide a promising approach for enhancing both the transmittable resolution and distance that standard copper-based cables cannot reach. In addition to the standard digital formats such as HDMI, the high-resolution, long-distance transfer of VGA format signals is important for applications where high-resolution analog video ports should be also supported, such as military/defense applications and high-resolution video camera links. In this presentation we present the development of a compressionless, high-resolution (up to WUXGA, 1920x1200), long-distance (up to 2 km) VGA extenders based on serialized technique. We employed asynchronous serial transmission and clock regeneration techniques, which enables lower cost implementation of VGA extenders by removing the necessity for clock transmission and large memory at the receiver. Two 3.125-Gbps transceivers are used in parallel to meet the required maximum video data rate of 6.25 Gbps. As the data are transmitted asynchronously, 24-bit pixel clock time stamp is employed to regenerate video pixel clock accurately at the receiver side. In parallel to the video information, stereo audio and RS-232 control signals are transmitted as well.

Assessment of NDE for key indicators of aging cables in nuclear power plants - Interim status

NASA Astrophysics Data System (ADS)

Glass, S. W.; Ramuhalli, P.; Fifield, L. S.; Prowant, M. S.; Dib, G.; Tedeschi, J. R.; Suter, J. D.; Jones, A. M.; Good, M. S.; Pardini, A. F.; Hartman, T. S.

2016-02-01

Degradation of the cable jacket, electrical insulation, and other cable components of installed cables within nuclear power plants (NPPs) is known to occur as a function of age, temperature, radiation, and other environmental factors. System tests verify cable function under normal loads; however, the concern is over cable performance under exceptional loads associated with design-basis events (DBEs). The cable's ability to perform safely over the initial 40-year planned and licensed life has generally been demonstrated and there have been very few age-related cable failures. With greater than 1000 km of power, control, instrumentation, and other cables typically found in an NPP, replacing all the cables would be a severe cost burden. Justification for life extension to 60 and 80 years requires a cable aging management program to justify cable performance under normal operation as well as accident conditions. Currently the gold standard for determining cable insulation degradation is the elongation-at-break (EAB). This, however, is an ex-situ measurement and requires removal of a sample for laboratory investigation. A reliable nondestructive examination (NDE) in-situ approach is desirable to objectively determine the suitability of the cable for service. A variety of tests are available to assess various aspects of electrical and mechanical cable performance, but none of these tests are suitable for all cable configurations nor does any single test confirm all features of interest. Nevertheless, the complete collection of test possibilities offers a powerful range of tools to assure the integrity of critical cables. Licensees and regulators have settled on a practical program to justify continued operation based on condition monitoring of a lead sample set of cables where test data is tracked in a database and the required test data are continually adjusted based on plant and fleet-wide experience. As part of the Light Water Reactor Sustainability program sponsored by the U.S. Nuclear Regulatory Commission, the U.S. Department of Energy, and industry (represented by the Electric Power Research Institute), an assessment of cable NDE methods was commissioned. Technologies include both bulk electrical measurements (Tan δ, time domain reflectometry, frequency domain reflectometry (FDR), partial discharge, and other techniques) and local insulation measurement (indenter, dynamic mechanical analysis interdigital capacitance, infrared spectral measurement, etc.). This aging cable NDE program update reviews the full range of techniques but focuses on the most interesting test approaches that have a chance to be deployed in-situ, particularly including Tan δ, FDR, and ultrasound methods that have been reviewed most completely in this progress period.

Fiber optic reference frequency distribution to remote beam waveguide antennas

NASA Technical Reports Server (NTRS)

Calhoun, Malcolm; Kuhnle, Paul; Law, Julius

1995-01-01

In the NASA/JPL Deep Space Network (DSN), radio science experiments (probing outer planet atmospheres, rings, gravitational waves, etc.) and very long-base interferometry (VLBI) require ultra-stable, low phase noise reference frequency signals at the user locations. Typical locations for radio science/VLBI exciters and down-converters are the cone areas of the 34 m high efficiency antennas or the 70 m antennas, located several hundred meters from the reference frequency standards. Over the past three years, fiber optic distribution links have replaced coaxial cable distribution for reference frequencies to these antenna sites. Optical fibers are the preferred medium for distribution because of their low attenuation, immunity to EMI/IWI, and temperature stability. A new network of Beam Waveguide (BWG) antennas presently under construction in the DSN requires hydrogen maser stability at tens of kilometers distance from the frequency standards central location. The topic of this paper is the design and implementation of an optical fiber distribution link which provides ultra-stable reference frequencies to users at a remote BWG antenna. The temperature profile from the earth's surface to a depth of six feet over a time period of six months was used to optimize the placement of the fiber optic cables. In-situ evaluation of the fiber optic link performance indicates Allan deviation on the order of parts in 10(exp -15) at 1000 and 10,000 seconds averaging time; thus, the link stability degradation due to environmental conditions still preserves hydrogen maser stability at the user locations. This paper reports on the implementation of optical fibers and electro-optic devices for distributing very stable, low phase noise reference signals to remote BWG antenna locations. Allan deviation and phase noise test results for a 16 km fiber optic distribution link are presented in the paper.

Fiber optic reference frequency distribution to remote beam waveguide antennas

NASA Astrophysics Data System (ADS)

Calhoun, Malcolm; Kuhnle, Paul; Law, Julius

1995-05-01

In the NASA/JPL Deep Space Network (DSN), radio science experiments (probing outer planet atmospheres, rings, gravitational waves, etc.) and very long-base interferometry (VLBI) require ultra-stable, low phase noise reference frequency signals at the user locations. Typical locations for radio science/VLBI exciters and down-converters are the cone areas of the 34 m high efficiency antennas or the 70 m antennas, located several hundred meters from the reference frequency standards. Over the past three years, fiber optic distribution links have replaced coaxial cable distribution for reference frequencies to these antenna sites. Optical fibers are the preferred medium for distribution because of their low attenuation, immunity to EMI/IWI, and temperature stability. A new network of Beam Waveguide (BWG) antennas presently under construction in the DSN requires hydrogen maser stability at tens of kilometers distance from the frequency standards central location. The topic of this paper is the design and implementation of an optical fiber distribution link which provides ultra-stable reference frequencies to users at a remote BWG antenna. The temperature profile from the earth's surface to a depth of six feet over a time period of six months was used to optimize the placement of the fiber optic cables. In-situ evaluation of the fiber optic link performance indicates Allan deviation on the order of parts in 10(exp -15) at 1000 and 10,000 seconds averaging time; thus, the link stability degradation due to environmental conditions still preserves hydrogen maser stability at the user locations. This paper reports on the implementation of optical fibers and electro-optic devices for distributing very stable, low phase noise reference signals to remote BWG antenna locations. Allan deviation and phase noise test results for a 16 km fiber optic distribution link are presented in the paper.

High speed optical wireless data transmission system for particle sensors in high energy physics

NASA Astrophysics Data System (ADS)

Ali, W.; Corsini, R.; Ciaramella, E.; Dell'Orso, R.; Messineo, A.; Palla, F.

2015-08-01

High speed optical fiber or copper wire communication systems are frequently deployed for readout data links used in particle physics detectors. Future detector upgrades will need more bandwidth for data transfer, but routing requirements for new cables or optical fiber will be challenging due to space limitations. Optical wireless communication (OWC) can provide high bandwidth connectivity with an advantage of reduced material budget and complexity of cable installation and management. In a collaborative effort, Scuola Superiore Sant'Anna and INFN Pisa are pursuing the development of a free-space optical link that could be installed in a future particle physics detector or upgrade. We describe initial studies of an OWC link using the inner tracker of the Compact Muon Solenoid (CMS) detector as a reference architecture. The results of two experiments are described: the first to verify that the laser source transmission wavelength of 1550 nm will not introduce fake signals in silicon strip sensors while the second was to study the source beam diameter and its tolerance to misalignment. For data rates of 2.5 Gb/s and 10 Gb/s over a 10 cm working distance it was observed that a tolerance limit of ±0.25 mm to ±0.8 mm can be obtained for misaligned systems with source beam diameters of 0.38 mm to 3.5 mm, respectively.

Fiber optic oxygen sensor leak detection system for space applications

NASA Astrophysics Data System (ADS)

Kazemi, Alex A.; Goswami, Kish; Mendoza, Edgar A.; Kempen, Lothar U.

2007-09-01

This paper describes the successful test of a multi-point fiber optic oxygen sensor system during the static firing of an Evolved Expandable Launch Vehicle (EELV)/Delta IV common booster core (CBC) rocket engine at NASA's Stennis Flight Center. The system consisted of microsensors (optrodes) using an oxygen gas sensitive indicator incorporated onto an optically transparent porous substrate. The modular optoelectronics and multiplexing network system was designed and assembled utilizing a multi-channel opto-electronic sensor readout unit that monitored the oxygen and temperature response of the individual optrodes in real-time and communicated this information via a serial communication port to a remote laptop computer. The sensor packaging for oxygen consisted of two optrodes - one doped with an indicator sensitive to oxygen, and the other doped with an indicator sensitive to temperature. The multichannel oxygen sensor system is fully reversible. It has demonstrated a dynamic response to oxygen gas in the range of 0% to 100% with 0.1% resolution and a response time of <=10 seconds. The sensor package was attached to a custom fiber optic ribbon cable, which was then connected to a fiber optic trunk communications cable (standard telecommunications-grade fiber) that connected to the optoelectronics module. Each board in the expandable module included light sources, photo-detectors, and associated electronics required for detecting oxygen and temperature. The paper illustrates the sensor design and performance data under field deployment conditions.

Thin-film optical initiator

DOEpatents

Erickson, Kenneth L.

2001-01-01

A thin-film optical initiator having an inert, transparent substrate, a reactive thin film, which can be either an explosive or a pyrotechnic, and a reflective thin film. The resultant thin-film optical initiator system also comprises a fiber-optic cable connected to a low-energy laser source, an output charge, and an initiator housing. The reactive thin film, which may contain very thin embedded layers or be a co-deposit of a light-absorbing material such as carbon, absorbs the incident laser light, is volumetrically heated, and explodes against the output charge, imparting about 5 to 20 times more energy than in the incident laser pulse.

Opportunities and challenges for optical wireless: the competitive advantage of free space telecommunications links in today's crowded marketplace

NASA Astrophysics Data System (ADS)

Carbonneau, Theresa H.; Wisely, David R.

1998-01-01

Never before has the opportunity for terrestrial optical wireless communications links been so great. The high data rates attainable, up to OC-24, make it a very attractive and cost effective alternative to traditional fiber optic and microwave links. With today's demand for interactive multimedia-based applications, such as video conferencing and telemedicine, optical wireless products are the only ones that can provide the needed bandwidth in situations when it is too costly or impossible to install fiber optic cable. Recent developments in laser and optics technologies, in addition to auto beam tracking, permit transmission units to achieve excellent performance rates in all weather conditions.

Laser ablation system, and method of decontaminating surfaces

DOEpatents

Ferguson, Russell L.; Edelson, Martin C.; Pang, Ho-ming

1998-07-14

A laser ablation system comprising a laser head providing a laser output; a flexible fiber optic cable optically coupled to the laser output and transmitting laser light; an output optics assembly including a nozzle through which laser light passes; an exhaust tube in communication with the nozzle; and a blower generating a vacuum on the exhaust tube. A method of decontaminating a surface comprising the following steps: providing an acousto-optic, Q-switched Nd:YAG laser light ablation system having a fiber optically coupled output optics assembly; and operating the laser light ablation system to produce an irradiance greater than 1.times.10.sup.7 W/cm.sup.2, and a pulse width between 80 and 170 ns.

Evolution of low-profile and lightweight electrical connectors for soldier-worn applications

NASA Astrophysics Data System (ADS)

Gans, Eric; Lee, Kang; Jannson, Tomasz; Walter, Kevin

2011-06-01

In addition to military radios, modern warfighters carry cell phones, GPS devices, computers, and night-vision aids, all of which require electrical cables and connectors for data and power transmission. Currently each electrical device operates via independent cables using conventional cable and connector technology. Conventional cables are stiff and difficult to integrate into a soldier-worn garment. Conventional connectors are tall and heavy, as they were designed to ensure secure connections to bulkhead-type panels, and being tall, represent significant snag-hazards in soldier-worn applications. Physical Optics Corporation has designed a new, lightweight and low-profile electrical connector that is more suitable for body-worn applications and operates much like a standard garment snap. When these connectors are mated, the combined height is <0.3 in. - a significant reduction from the 2.5 in. average height of conventional connectors. Electrical connections can be made with one hand (gloved or bare) and blindly (without looking). Furthermore, POC's connectors are integrated into systems that distribute data or power from a central location on the soldier's vest, reducing the length and weight of the cables necessary to interconnect various mission-critical electronic systems. The result is a lightweight power/data distribution system offering significant advantages over conventional electrical connectors in soldier-worn applications.

77 FR 43592 - Public Utility District No. 1 of Snohomish County, WA; Notice of Technical Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-25

... issues raised by PC Landing and the Federal Communications Commission regarding the proximity of the proposed Admiralty Inlet Tidal Project to PC Landing's fiber optic communication cable, and discuss the...

Multimedia Equipment for Distance Education.

ERIC Educational Resources Information Center

Schiller, Scott S.

1993-01-01

Discusses the use of multimedia equipment for distance education. Topics addressed include use of the Internet; distance learning for educators; and cable television and/or fiber optics, including interactive television and satellite technology. A sidebar lists online and telecommunications providers. (LRW)

Digital Telematics: Present and Future.

ERIC Educational Resources Information Center

Stalberg, Christian E.

1987-01-01

This overview of developments in international telecommunications networks focuses on their importance for developing countries and the necessary interdependence of all countries. Highlights include digital technology, telephone service, packet switching networks, communications satellites, fiber optic cables, and possible future developments.…

Overview of technical trend of optical fiber/cable and research and development strategy of Samsung

NASA Astrophysics Data System (ADS)

Kim, Jin H.

2005-01-01

Fiber-to-the-Premise (FTTP), a keyword in the current fiber and cable industry, leads us variegated directions of the research and development activities. In fact, this momentum of industry seems to be weak yet, since the bandwidth demand by market is still unbalanced to the capacity in the several market segments. However, the recent gradual recovery in metro and access network indicates a positive sign for FTTP deployment projects. It is the very preferable for us to optimize R&D strategy applicable to the current market trend of sequential investment.

Hybrid intracerebral probe with integrated bare LED chips for optogenetic studies.

PubMed

Ayub, Suleman; Gentet, Luc J; Fiáth, Richárd; Schwaerzle, Michael; Borel, Mélodie; David, François; Barthó, Péter; Ulbert, István; Paul, Oliver; Ruther, Patrick

2017-09-01

This article reports on the development, i.e., the design, fabrication, and validation of an implantable optical neural probes designed for in vivo experiments relying on optogenetics. The probes comprise an array of ten bare light-emitting diode (LED) chips emitting at a wavelength of 460 nm and integrated along a flexible polyimide-based substrate stiffened using a micromachined ladder-like silicon structure. The resulting mechanical stiffness of the slender, 250-μm-wide, 65-μm-thick, and 5- and 8-mm-long probe shank facilitates its implantation into neural tissue. The LEDs are encapsulated by a fluropolymer coating protecting the implant against the physiological conditions in the brain. The electrical interface to the external control unit is provided by 10-μm-thick, highly flexible polyimide cables making the probes suitable for both acute and chronic in vivo experiments. Optical and electrical properties of the probes are reported, as well as their in vivo validation in acute optogenetic studies in transgenic mice. The depth-dependent optical stimulation of both excitatory and inhibitory neurons is demonstrated by altering the brain activity in the cortex and the thalamus. Local network responses elicited by 20-ms-long light pulses of different optical power (20 μW and 1 mW), as well as local modulation of single unit neuronal activity to 1-s-long light pulses with low optical intensity (17 μW) are presented. The ability to modulate neural activity makes these devices suitable for a broad variety of optogenetic experiments.

30 CFR Appendix I to Subpart D of... - Appendix I to Subpart D of Part 18

Code of Federal Regulations, 2011 CFR

2011-07-01

... diameter of three-conductor portable power cables with tolerances in inches—601 to 5,000 volts. 8 Fuse... diameters. Table 1—Portable Power Cable Ampacities—600 Volts (Amperes Per Conductor Based on 60 °C. Copper Temperature—40 °C. Ambient) Conductor size—AWG or MCM Single conductor 2-conductor, round or flat 3-conductor...

30 CFR Appendix I to Subpart D of... - Appendix I to Subpart D of Part 18

Code of Federal Regulations, 2010 CFR

2010-07-01

... diameter of three-conductor portable power cables with tolerances in inches—601 to 5,000 volts. 8 Fuse... diameters. Table 1—Portable Power Cable Ampacities—600 Volts (Amperes Per Conductor Based on 60 °C. Copper Temperature—40 °C. Ambient) Conductor size—AWG or MCM Single conductor 2-conductor, round or flat 3-conductor...

Fiber-Optic Network Architectures for Onboard Avionics Applications Investigated

NASA Technical Reports Server (NTRS)

Nguyen, Hung D.; Ngo, Duc H.

2003-01-01

This project is part of a study within the Advanced Air Transportation Technologies program undertaken at the NASA Glenn Research Center. The main focus of the program is the improvement of air transportation, with particular emphasis on air transportation safety. Current and future advances in digital data communications between an aircraft and the outside world will require high-bandwidth onboard communication networks. Radiofrequency (RF) systems, with their interconnection network based on coaxial cables and waveguides, increase the complexity of communication systems onboard modern civil and military aircraft with respect to weight, power consumption, and safety. In addition, safety and reliability concerns from electromagnetic interference between the RF components embedded in these communication systems exist. A simple, reliable, and lightweight network that is free from the effects of electromagnetic interference and capable of supporting the broadband communications needs of future onboard digital avionics systems cannot be easily implemented using existing coaxial cable-based systems. Fiber-optical communication systems can meet all these challenges of modern avionics applications in an efficient, cost-effective manner. The objective of this project is to present a number of optical network architectures for onboard RF signal distribution. Because of the emergence of a number of digital avionics devices requiring high-bandwidth connectivity, fiber-optic RF networks onboard modern aircraft will play a vital role in ensuring a low-noise, highly reliable RF communication system. Two approaches are being used for network architectures for aircraft onboard fiber-optic distribution systems: a hybrid RF-optical network and an all-optical wavelength division multiplexing (WDM) network.

Low Cost Fiber Optic Cable Assemblies for Local Distribution Systems

DTIC Science & Technology

1977-04-01

coefficient of friction, and is chemically inert. PFA exhibits low water permeability and ab- sorption . FEP-100 and FEP-110 were initially extruded over T08...with FEP 110. To overcome these problems, Teflon PFA 9704 was evaluated. It exhibited good extrudability which allowed application of thin and thick...superior extrudability, in addition to meeting the optical characteristics required for a cladding material, Teflon PFA was considered a viable

Improve the refractive index sensitivity of coaxial-cable type gold nanostructure: the effect of dielectric polarization from the separate layer

NASA Astrophysics Data System (ADS)

Zhu, Jian; Li, Jian-Jun; Zhao, Jun-Wu

2013-06-01

The separate layer refractive index sensitivity of a coaxial-cable type three-layered gold nanotube has been studied. Theoretical calculation results based on quasi-static model show that the coaxial-cable type gold nanostructure has higher refractive index sensitivity than that of single-layered gold nanotube. This sensitivity could be improved by increasing the inner wire radius or decreasing the total radius of the tube, and the maximum sensitivity may exceed 1,000 nm per refractive index unit. The physical origin was also investigated based on the coupling of the dielectric media induced polarizations and the local electric fields in separate layer and outer surrounding. These separate layer refractive index sensing properties of coaxial-cable type gold nanostructure present well potential for plasmonic biosensing applications.

Development of Murray Loop Bridge for High Induced Voltage

NASA Astrophysics Data System (ADS)

Isono, Shigeki; Kawasaki, Katsutoshi; Kobayashi, Shin-Ichi; Ishihara, Hayato; Chiyajo, Kiyonobu

In the case of the cable fault that ground fault resistance is less than 10MΩ, Murray Loop Bridge is excellent as a fault locator in location accuracy and the convenience. But, when the induction of several hundred V is taken from the single core cable which adjoins it, a fault location with the high voltage Murray Loop Bridge becomes difficult. Therefore, we developed Murray Loop Bridge, which could be applied even when the induced voltage of several hundred V occurs in the measurement cable. The evaluation of the fault location accuracy was done with the developed prototype by the actual line and the training equipment.

Design versions of HTS three-phase cables with the minimized value of AC losses

NASA Astrophysics Data System (ADS)

Altov, V. A.; Balashov, N. N.; Degtyarenko, P. N.; Ivanov, S. S.; Kopylov, S. I.; Lipa, DA; Samoilenkov, S. V.; Sytnikov, V. E.; Zheltov, V. V.

2018-03-01

Design versions of HTS three-phase cables consisting of 2G HTS tapes have been investigated by the numerical simulation method with the aim of AC losses minimization. Two design versions of cables with the coaxial and extended rectangular cross-section shape are considered – the non-sectioned and sectioned one. In the latter each cable phase consists of sections connected in parallel. The optimal dimensions of sections and order of their alteration are chosen by appropriate calculations. The model used takes into account the current distribution between the sections and its non-uniformity within each single HTS tape as well. The following characteristics are varied: design version, dimension, positioning of extra copper layer in a cable, design of HTS tapes themselves and their mutual position. The dependence of AC losses on the latter two characteristics is considered in details, and the examples of cable designs optimized by the total set of characteristics for the medium class of voltages (10 – 60 kV) are given. At the critical current JC=5.1 кA per phase and current amplitudes lower than 0.85JC, the level of total AC losses does not exceed the natural cryostat heat losses.

Reversible, high-voltage square-wave pulse generator for triggering spark gaps.

PubMed

Robledo-Martinez, A; Vega, R; Cuellar, L E; Ruiz-Meza, A; Guzmán, E

2007-05-01

A design is presented for a reversible, square-pulse generator that employs coaxial cables for charge storage and pulse formation and a thyratron as the switch. The generator has a nominal output voltage of 5-30 kV and a pulse duration determined by the cable's physical length. Two variations are presented: (1) a single-stage one consisting of cable that is charged via its shield on one end and discharged with a thyratron on the opposite end and (2) a two-stage one having an inverting circuit that uses a coaxial cable to reverse the polarity of the pulse. The generator operates with "flying shields," i.e., high-voltage pulses also propagate on the outside of the cables; this calls for a dedicated insulation that avoids breakdown between sections of the cable's shield. The rise time obtained is mostly dictated by the switching time of the thyratron; with the one we used in the tests, rise times in the range of 30-40 ns were obtained. We present the results obtained in the implementation of the generators as well as its application to fire a large Marx generator.

Modified van Vaals-Bergman coaxial cable coil (lambda coil) for high-field imaging.

PubMed

Matsuzawa, H; Nakada, T

1996-03-01

An easily constructed, low-capacitive coupling volume coil based on the van Vaals-Bergman coaxial cable coil for high field imaging is described. The coil (designated "lambda coil") was constructed using two 5/4 length 50 omega coaxial cables matched to a 50 omega transmission line with LC bridge balun. The standing wave on the single 5/4 lambda length coaxial cable provides two points of current maxima in oppositional direction. Therefore, the four current elements necessary for effective B1 field generation can be obtained by two 5/4 lambda length coaxial cables arranged analogous to 1/2 lambda T-antenna. Capacitive coupling between the coil elements and conductive samples (i.e. animals) is minimized by simply retaining the shield of the coaxial cable for the area of voltage maxima. The lambda coil exhibited excellent performance as a volume coil with a high quality factor and highly homogeneous rf fields. Because of its dramatically simple architecture and excellent performance, the lambda coil configuration appears to be an economical alternative to the original van Vaals-Bergman design, especially for research facilities with a high field magnet and limited bore space.

In-plane modal frequencies and mode shapes of two stay cables interconnected by uniformly distributed cross-ties

NASA Astrophysics Data System (ADS)

Jing, Haiquan; He, Xuhui; Zou, Yunfeng; Wang, Hanfeng

2018-03-01

Stay cables are important load-bearing structural elements of cable-stayed bridges. Suppressing the large vibrations of the stay cables under the external excitations is of worldwide concern for the bridge engineers and researchers. Over the past decade, the use of crosstie has become one of the most practical and effective methods. Extensive research has led to a better understanding of the mechanics of cable networks, and the effects of different parameters, such as length ratio, mass-tension ratio, and segment ratio on the effectiveness of the crosstie have been investigated. In this study, uniformly distributed elastic crossties serve to replace the traditional single, or several cross-ties, aiming to delay "mode localization." A numerical method is developed by replacing the uniformly distributed, discrete elastic cross-tie model with an equivalent, continuously distributed, elastic cross-tie model in order to calculate the modal frequencies and mode shapes of the cable-crosstie system. The effectiveness of the proposed method is verified by comparing the elicited results with those obtained using the previous method. The uniformly distributed elastic cross-ties are shown to significantly delay "mode localization."

Measuring signal-to-noise ratio automatically

NASA Technical Reports Server (NTRS)

Bergman, L. A.; Johnston, A. R.

1980-01-01

Automated method of measuring signal-to-noise ratio in digital communication channels is more precise and 100 times faster than previous methods used. Method based on bit-error-rate (B&R) measurement can be used with cable, microwave radio, or optical links.

Recent Developments in Fibers for Telecommunications

NASA Astrophysics Data System (ADS)

Caronna, V.; Cocchini, F.; Collaro, A.; Cuomo, D.; Ruzzier, M.; Schiaffo, A.; Terruzzi, L.; Valls, A.

Formerly known as Pirelli Cables and Systems, Prysmian Cables & Systems was founded in 2005, incorporating all previous Pirelli assets: "same knowledge, different names." Established in 1879, the company has more than 50 factories worldwide, operating in energy and telecommunications sectors. The main fiber manufacturing facility, Fibre Ottiche Sud (FOS), located in Italy, is operating since 1984 using the outside vapor deposition (OVD) technology and adopting today a proprietary coating system, Neon Plus. More than 40 Mkm of fibers produced in all Prysmian factories have been installed worldwide until now. Research activities are extensively carried out both in the headquarters based in Milan, Italy, and in several developments in different factories. This article will present the more noticeable results achieved in the past few years in developing Prysmian products out of its different activities in telecommunications, specifically in the optical fiber sector, while leaving to published papers the description of developments in cable design and connectivity products [1, 2].

Using digital image correlation and three dimensional point tracking in conjunction with real time operating data expansion techniques to predict full-field dynamic strain

NASA Astrophysics Data System (ADS)

Avitabile, Peter; Baqersad, Javad; Niezrecki, Christopher

2014-05-01

Large structures pose unique difficulties in the acquisition of measured dynamic data with conventional techniques that are further complicated when the structure also has rotating members such as wind turbine blades and helicopter blades. Optical techniques (digital image correlation and dynamic point tracking) are used to measure line of sight data without the need to contact the structure, eliminating cumbersome cabling issues. The data acquired from these optical approaches are used in conjunction with a unique real time operating data expansion process to obtain full-field dynamic displacement and dynamic strain. The measurement approaches are described in this paper along with the expansion procedures. The data is collected for a single blade from a wind turbine and also for a three bladed assembled wind turbine configuration. Measured strains are compared to results from a limited set of optical measurements used to perform the expansion to obtain full-field strain results including locations that are not available from the line of sight measurements acquired. The success of the approach clearly shows that there are some very extraordinary possibilities that exist to provide very desperately needed full field displacement and strain information that can be used to help identify the structural health of structures.

Optical-Fiber Power Meter Comparison Between NIST and PTB.

PubMed

Vayshenker, I; Haars, H; Li, X; Lehman, J H; Livigni, D J

2003-01-01

We describe the results of a comparison of reference standards between the National Institute of Standards and Technology (NIST-USA) and Physikalisch-Technische Bundesanstalt (PTB-Germany) at nominal wavelengths of 1300 nm and 1550 nm using an optical-fiber cable. Both laboratories used thermal detectors as reference standards. A novel temperature-controlled, optical-trap detector was used as a transfer standard to compare two reference standards. Measurement results showed differences of less than 1.5 × 10(-3), which is within the combined uncertainty for both laboratories.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Emanuela Barzi et al.

Fermilab is developing 11 T superconducting dipole magnets for future accelerators based on Nb{sub 3}Sn conductor. Within the High Field Magnet Project, the first prototypes feature 1 meter long two-layer shell-type coils and common coils. For the former, keystoned Rutherford-type cable made of 28 Nb{sub 3}Sn strands 1 mm in diameter are used, whereas for the latter a 60-strand flat cable was chosen. Multifilamentary Nb{sub 3}Sn strands produced with various technologies by industry were used for the development and testing of the prototype cable. An experimental cabling machine with up to 28-strand capacity that has been recently purchased, installed andmore » commissioned at Fermilab, has allowed further advances in strand and cable studies. Cables of 27 and 28 strands of various structures (single strands or assemblies of sub-strands), with aspect ratios from 7 to 17, packing factors from 85 to 95%, with and without a stainless steel core were made out of Copper, NbTi, and Modified Jelly Roll (OST), Powder-in-Tube (SMI) and Internal Tin (Mitsubishi) Nb{sub 3}Sn strands. optimal parameters were determined with respect to mechanical and electrical properties, including critical current degradation, interstrand resistance, etc. Round strands of the same billets used in the cables were deformed by rolling them down to various thicknesses. Their critical current Ic was then measured and compared with that of the strands extracted from cables having different packing factors. This paper summarizes the results of such R and D efforts at Fermilab.« less

Linearized Model of an Actively Controlled Cable for a Carlina Diluted Telescope

NASA Astrophysics Data System (ADS)

Andersen, T.; Le Coroller, H.; Owner-Petersen, M.; Dejonghe, J.

2014-04-01

The Carlina thinned pupil telescope has a focal unit (``gondola'') suspended by cables over the primary mirror. To predict the structural behavior of the gondola system, a simulation building block of a single cable is needed. A preloaded cable is a strongly non-linear system and can be modeled either with partial differential equations or non-linear finite elements. Using the latter, we set up an iteration procedure for determination of the static cable form and we formulate the necessary second-order differential equations for such a model. We convert them to a set of first-order differential equations (an ``ABCD''-model). Symmetrical in-plane eigenmodes and ``axial'' eigenmodes are the only eigenmodes that play a role in practice for a taut cable. Using the model and a generic suspension, a parameter study is made to find the influence of various design parameters. We conclude that the cable should be as stiff and thick as practically possible with a fairly high preload. Steel or Aramid are suitable materials. Further, placing the cable winches on the gondola and not on the ground does not provide significant advantages. Finally, it seems that use of reaction-wheels and/or reaction-masses will make the way for more accurate control of the gondola position under wind load. An adaptive stage with tip/tilt/piston correction for subapertures together with a focus and guiding system for freezing the fringes must also be studied.

Optical data transmission technology for fixed and drag-on STS payloads umbilicals. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

St.denis, R. W.

1981-01-01

The feasibility of using optical data handling methods to transmit payload checkout and telemetry is discussed. Optical communications are superior to conventional communication systems for the following reasons: high data capacity optical channels; small and light weight optical cables; and optical signal immunity to electromagnetic interference. Task number one analyzed the ground checkout data requirements that may be expected from the payload community. Task number two selected the optical approach based on the interface requirements, the location of the interface, the amount of time required to reconfigure hardware, and the method of transporting the optical signal. Task number three surveyed and selected optical components for the two payload data link. Task number four makes a qualitative comparison of the conventional electrical communication system and the proposed optical communication system.

Field demonstration of an eight-element fiber laser hydrophone array

NASA Astrophysics Data System (ADS)

Foster, Scott; Tikhomirov, Alexei; Harrison, Joanne; van Velzen, John

2014-05-01

We have developed an 8-element fibre laser seabed array demonstrating state-of-the art performance characteristics for a fibre laser sensing system and highlighting the advantage this technology provides in the underwater sensing domain. The system employs sea-state-zero sensitivity hydrophones with a flat acoustic response over a bandwidth exceeding 5kHz and very low inertial sensitivity. The system contains no outboard electronics and few metal components making it extremely light, compact, and low complexity. The array may be deployed up to 4 km from a land or sea based platform to a depth of up to 80m. Power delivery and telemetry for all 8 sensors is achieved via a single 2mm diameter optical fibre cable weighing less than 5kg per km. We report here results of the first field trials of this system.

Thin film technologies for optoelectronic components in fiber optic communication

NASA Astrophysics Data System (ADS)

Perinati, Agostino

1998-02-01

'The Asian Routes Towards the Global Information Society' and 'Towards a Strategic Planning for the Global Information Society' will be the forum themes of 'Asia Telecom 97' and 'Telecom Interactice 97' events respectively, to be held by the International Telecommunication Union (ITU) in order to further telecommunication development around the world. International telecommunications network affects our life by keeping us in touch, bringing us world news and underpinning the global economy. Global tele-economy, global information infrastructure, global information society terms are more and more used to indicate the evolution towards an information- driven world where the access to information, communication and technologies is essential to the economic and social development in every country. Telecommunication industry can strongly contribute to this evolution together with broadcasting and computer industry, and fiber optic communications are expected to continue to grow up and share a relevant part of the total telecom market. In 1995 telecom market shown a 3.8 percent worldwide investment growth reaching a 545 billion value. According to 'Kessler Marketing Intelligence (KMI) Corp.' analysis of fiberoptics and multimedia market the amount of cabled fiber installed in U.S. will be around 11 million fiber-km in 1997 and 15 million fiber-km are predicted in the year 2000. Between 1995 and 1998 the undersea industry is estimated to deal with 13.9 billion as additional undersea cable systems investment in the global telecom network. In China beside satellite telecom stations and digital microwave systems 22 fiber optic backbones have been realized and another 23 systems are expected to be built in the Ninth Five-Year National Plan (1996 to approximately 2000) with a total length of nearly 30,000 sheat-km. The study, Fiber and Fiberoptic Cable Markets in China, recently released by KMI Corp. shows that fiber optic cable installation by MPT and other network operators will grow at an annual average rate of 22 percent from 1.3 million fiber-km in 1995 to 3.5 million fiber-km in 2000. The worldwide components market-cable, transceivers and connectors - 6.1 billion in 1994, is forecasted to grow and show a 19 percent combined annual growth rate through the year 2000 when is predicted to reach 17.38 billion. Fiber-in-the-loop and widespread use of switched digital services will dominate this scenario being the fiber the best medium for transmitting multimedia services. As long as communication will partially replace transportation, multimedia services will push forward technology for systems and related components not only for higher performances but for lower cost too in order to get the consumers wanting to buy the new services. In the long distance transmission area (trunk network) higher integration of electronic and optoelectronic functions are required for transmitter and receiver in order to allow for higher system speed, moving from 2.5 Gb/s to 5, 10, 40 Gb/s; narrow band wavelength division multiplexing (WDM) filters are required for higher transmission capacity through multiwavelength technique and for optical amplifier. In the access area (distribution network) passive components as splitters, couplers, filters are needed together with optical amplifiers and transceivers for point-to-multipoint optical signal distribution: main issue in this area is the total cost to be paid by the customer for basic and new services. Multimedia services evolution, through fiber to the home and to the desktop approach, will be mainly affected by the availability of technologies suitable for component consistent integration, high yield manufacturing processes and final low cost. In this paper some of the optoelectronic components and related thin film technologies expected to mainly affect the fiber optic transmission evolution, either for long distance telecommunication systems or for subscriber network, are presented.

Optical gamma thermometer

DOEpatents

Koster, Glen Peter; Xia, Hua; Lee, Boon Kwee

2013-08-06

An optical gamma thermometer includes a metal mass having a temperature proportional to a gamma flux within a core of a nuclear reactor, and an optical fiber cable for measuring the temperature of the heated metal mass. The temperature of the heated mass may be measured by using one or more fiber grating structures and/or by using scattering techniques, such as Raman, Brillouin, and the like. The optical gamma thermometer may be used in conjunction with a conventional reactor heat balance to calibrate the local power range monitors over their useful in-service life. The optical gamma thermometer occupies much less space within the in-core instrument tube and costs much less than the conventional gamma thermometer.

Pixelized Device Control Actuators for Large Adaptive Optics

NASA Technical Reports Server (NTRS)

Knowles, Gareth J.; Bird, Ross W.; Shea, Brian; Chen, Peter

2009-01-01

A fully integrated, compact, adaptive space optic mirror assembly has been developed, incorporating new advances in ultralight, high-performance composite mirrors. The composite mirrors use Q-switch matrix architecture-based pixelized control (PMN-PT) actuators, which achieve high-performance, large adaptive optic capability, while reducing the weight of present adaptive optic systems. The self-contained, fully assembled, 11x11x4-in. (approx.= 28x28x10-cm) unit integrates a very-high-performance 8-in. (approx.=20-cm) optic, and has 8-kHz true bandwidth. The assembled unit weighs less than 15 pounds (=6.8 kg), including all mechanical assemblies, power electronics, control electronics, drive electronics, face sheet, wiring, and cabling. It requires just three wires to be attached (power, ground, and signal) for full-function systems integration, and uses a steel-frame and epoxied electronics. The three main innovations are: 1. Ultralightweight composite optics: A new replication method for fabrication of very thin composite 20-cm-diameter laminate face sheets with good as-fabricated optical figure was developed. The approach is a new mandrel resin surface deposition onto previously fabricated thin composite laminates. 2. Matrix (regenerative) power topology: Waveform correction can be achieved across an entire face sheet at 6 kHz, even for large actuator counts. In practice, it was found to be better to develop a quadrant drive, that is, four quadrants of 169 actuators behind the face sheet. Each quadrant has a single, small, regenerative power supply driving all 169 actuators at 8 kHz in effective parallel. 3. Q-switch drive architecture: The Q-switch innovation is at the heart of the matrix architecture, and allows for a very fast current draw into a desired actuator element in 120 counts of a MHz clock without any actuator coupling.

The Theseus Autonomous Underwater Vehicle: A Canadian Success Story

DTIC Science & Technology

1997-04-01

P502414.PDF [Page: 1 of 9] P502414.PDF [Page: 2 of 9] P502414.PDF [Page: 3 of 9] The Theseus Autonomous Underwater Vehicle A Canadian Success Story...autonomous underwater vehicle, named Theseus , for laying optical fiber cables in ice- covered waters. In trials and missions conducted in 1996, this...stations. An acoustic telemetry system enables communication with Theseus from surface stations, and an optical telemetry system is used for system

Blue Flag Distributed Wargaming System

DTIC Science & Technology

1992-07-01

combat simulation , and multi- site video teleconferencing (VTC). The Warrior Flag 90 feasibility demonstration was sponsored by the 4441st Tactical...provide RS-422 cross patching, loop -back and test points. At the hub six CSUs and two fiber optic modems were cabled in the normal-thru configuration...spare crypto or the fiber optic modem may be placed on-line via a patch. Loop plugs were provided for testing. Clock switches were provided to switch

Electro-Optics Millimeter/Microwave Technology in Japan. Report of DoD Technology Team.

DTIC Science & Technology

1985-05-01

Fiber Technology Hitachi is developing Ge-Se chalcogenide glass infrared optical fibers. Mate- rial development and evaluation has been carried out...chalcogenide glass fibers. The analysis indi- cates that the addition of Sb to Ge-Se chalcogenide glass should yield fibers with a very small absorption...representative of other commercial cables. Fiber is drawn using Vapor Axial Deposition (VAD) with pre-form glass ingots. Multiple fibers are combined

Superficial view of fiber to the home (FTTH)

NASA Astrophysics Data System (ADS)

Li, Xiaolin

2004-04-01

For the past few years, telecom companies have been working diligently to provide us with pseudo-broadband Internet connections over copper (DSL) and cable (cable modem). I use the term "pseudo-broadband" because the existing telecom infrastructure can only provide speeds of up to 1.5 megabits per second. (In theory, cable modem can provide up to 2.5 megabits per second, but in reality nobody obtains these speeds because the shared aspects of cable modem results in lower speeds.) No doubt improvements will be made over the next few years to squeeze more out of copper and cable, but it doesn't matter, because fiber to the home is coming, and it will be here faster than most people predict. In case you're wondering, FTTH provides download speeds of up to 155 megabits per second -- that's 100 times faster than the pseudo-broadband DSL and cable modem connections. Can you say instantaneous data transfer? Can you say, video on demand? SBC and Bellsouth are two of the telecom giants pioneering FTTH. The initial markets are new residential construction, because you don't have to dig up streets in an existing neighborhood to lay the fiber optic cable. SBC plans to wire 6,000 homes in a community in San Francisco by late next year. Initial net connections will only be about 5 MB/second -- far from the theoretical maximum of 155 MB/second, but still blazingly fast compared to DSL and cable modem. BellSouth is also pioneering FTTH with a trial project involving more than 400 people in the Atlanta suburb of Dunwoody. These individuals have Internet connections of about 10 MB/second! No doubt there will be stumbles along the way to providing FTTH. No doubt there are challenges to making FTTH cost effective. No doubt it will take years before most residences in the world have true broadband Internet access.

Handbook for Marine Geotechnical Engineering

DTIC Science & Technology

2012-02-01

height dictated by the chosen range. The returning acoustic signals are received by the same fish and transmitted by electrical or fiber optic cable......covered here, are required to predict penetrations in lithified sediments, coral, basalt , and other rock types. These special techniques are highly

The Miniaturized Autonomous Moored Profiler

DTIC Science & Technology

2004-07-20

power sleep mode. All collected data is stored on a flashcard memory module for later retrieval or remote transmission. With the optical telemetry...board flashcard for later retrieval or remote transmission. Although the descent operation ultimately depends upon the cable-pay, the CTD remains on

How to Choose a Media Retrieval System.

ERIC Educational Resources Information Center

Huber, Joe

1995-01-01

Provides guidelines for schools choosing a media retrieval system. Topics include broadband, baseband, coaxial cable, or fiber optic decisions; the control network; selecting scheduling software; presentation software; device control; control from the classroom; and a comparison of systems offered by five companies. (LRW)

29 CFR 1910.331 - Scope.

Code of Federal Regulations, 2010 CFR

2010-07-01

... or no such training) working on, near, or with the following installations: (1) Premises wiring. Installations of electric conductors and equipment within or on buildings or other structures, and on other... wiring. Installations of other outside conductors on the premises. (4) Optical fiber cable. Installations...

Extendible column can be stowed on drum

NASA Technical Reports Server (NTRS)

Holtz, G. M.; Howard, E. A.

1965-01-01

Column formed from a series of segments held together by an internal spring or cable can be coiled on a drum or extended into a rigid structure. This storable coil is useful in boring for soil samples and supporting electrical and optical sensors.

Applicability of cable theory to vascular conducted responses.

PubMed

Hald, Bjørn Olav; Jensen, Lars Jørn; Sørensen, Preben Graae; Holstein-Rathlou, Niels-Henrik; Jacobsen, Jens Christian Brings

2012-03-21

Conduction processes in the vasculature have traditionally been described using cable theory, i.e., locally induced signals decaying passively along the arteriolar wall. The decay is typically quantified using the steady-state length-constant, λ, derived from cable theory. However, the applicability of cable theory to blood vessels depends on assumptions that are not necessarily fulfilled in small arteries and arterioles. We have employed a morphologically and electrophysiologically detailed mathematical model of a rat mesenteric arteriole to investigate if the assumptions hold and whether λ adequately describes simulated conduction profiles. We find that several important cable theory assumptions are violated when applied to small blood vessels. However, the phenomenological use of a length-constant from a single exponential function is a good measure of conduction length. Hence, λ should be interpreted as a descriptive measure and not in light of cable theory. Determination of λ using cable theory assumes steady-state conditions. In contrast, using the model it is possible to probe how conduction behaves before steady state is achieved. As ion channels have time-dependent activation and inactivation, the conduction profile changes considerably during this dynamic period with an initially longer spread of current. This may have implications in relation to explaining why different agonists have different conduction properties. Also, it illustrates the necessity of using and developing models that handle the nonlinearity of ion channels. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Detection of structural damage in multiwire cables by monitoring the entropy evolution of wavelet coefficients

NASA Astrophysics Data System (ADS)

Ibáñez, Flor; Baltazar, Arturo; Mijarez, Rito; Aranda, Jorge

2015-03-01

Multiwire cables are widely used in important civil structures. Since they are exposed to several dynamic and static loads, their structural health can be compromised. The cables can also be submitted to mechanical contact, tension and energy propagation in addition to changes in size and material within their wires. Due to the critical role played by multiwire cables, it is necessary to develop a non-destructive health monitoring method to maintain their structure and proper performance. Ultrasonic inspection using guided waves is a promising non-destructive damage monitoring technique for rods, single wires and multiwire cables. The propagated guided waves are composed by an infinite number of vibrational modes making their analysis difficult. In this work, an entropy-based method to identify small changes in non-stationary signals is proposed. A system to capture and post-process acoustic signals is implemented. The Discrete Wavelet Transform (DWT) is computed in order to obtain the reconstructed wavelet coefficients of the signals and to analyze the energy at different scales. The feasibility of using the concept of entropy evolution of non-stationary signals to detect damage in multiwire cables is evaluated. The results show that there is a high correlation between the entropy value and damage level of the cable. The proposed method has low sensitivity to noise and reduces the computational complexity found in a typical time-frequency analysis.

Conceptual design of a multiple cable crane for planetary surface operations

NASA Technical Reports Server (NTRS)

Mikulas, Martin M., Jr.; Yang, Li-Farn

1991-01-01

A preliminary design study is presented of a mobile crane suitable for conducting remote, automated construction operations on planetary surfaces. A cursory study was made of earth based mobile cranes and the needs for major improvements were identified. Current earth based cranes have a single cable supporting the payload, and precision positioning is accomplished by the use of construction workers controlling the payload by the use of tethers. For remote, autonomous operations on planetary surfaces it will be necessary to perform the precision operations without the use of humans. To accomplish this the payload must be stabilized relative to the crane. One approach for accomplishing this is to suspend the payload on multiple cable. A 3-cable suspension system crane concept is discussed. An analysis of the natural frequency of the system is presented which verifies the legitimacy of the concept.

Myosin II dynamics are regulated by tension in intercalating cells.

PubMed

Fernandez-Gonzalez, Rodrigo; Simoes, Sérgio de Matos; Röper, Jens-Christian; Eaton, Suzanne; Zallen, Jennifer A

2009-11-01

Axis elongation in Drosophila occurs through polarized cell rearrangements driven by actomyosin contractility. Myosin II promotes neighbor exchange through the contraction of single cell boundaries, while the contraction of myosin II structures spanning multiple pairs of cells leads to rosette formation. Here we show that multicellular actomyosin cables form at a higher frequency than expected by chance, indicating that cable assembly is an active process. Multicellular cables are sites of increased mechanical tension as measured by laser ablation. Fluorescence recovery after photobleaching experiments show that myosin II is stabilized at the cortex in regions of increased tension. Myosin II is recruited in response to an ectopic force and relieving tension leads to a rapid loss of myosin, indicating that tension is necessary and sufficient for cortical myosin localization. These results demonstrate that myosin II dynamics are regulated by tension in a positive feedback loop that leads to multicellular actomyosin cable formation and efficient tissue elongation.

Preliminary design of land displacement-optical fiber sensor and analysis of observation during laboratory and field test

NASA Astrophysics Data System (ADS)

Bayuwati, Dwi; Waluyo, Tomi B.; Widiyatmoko, Bambang

2015-01-01

An optical fiber optic sensor for detecting land displacement is discussed in this paper. The sensor system consists of a laser at wavelength 1.3 um, optical fiber coupler, optical fiber as sensor and light transmitting media, PIN photodiodedetector system, data logger and personal computer. Sensor was made from a curved optical fiber with diameter 35 mm, which will be changed into a heart-shape fiber if it is pulled. The heart-shape fiber sensor is the modification of the earlier displacement fiber sensor model which was in an ellipse form. Light to and from the optical fiber sensor was transmitted into a length of a multi core, single mode optical fiber cable. The scheme of the optical displacement sensor system has been described here. Characterization in the laboratory has been done by applying a series of pulling mechanism, on the heart-shape fiber sensor; which represents the land displacement process. Characterization in the field was carried out by mounting the sensor system on a scaled-down model of a land slope and artificially reproducing the landslide process using a steady-flow of artificial rainfall as the trigger. The voltage sensor output was recorded during the artificial landslide process. The displacement occurence can be indicated from the declining of the sensor signal received by the detector while the reference signal is steady. Characterization in the laboratory resulted in the performance of the optical fiber land displacement, namely, sensitivity 0.027(mV/mV)/mm, resolution 0.37 mm and measurement range 30 mm; compared with earlier optical fiber sensor performance with similar sensitivity and resolution which works only in 8 mm displacement range. Based on the experiment of landslides simulation in the field, we can define a critical condition in the real situation before landslides occurence to take any measures to prevent more casualties and losses.

Convergence

NASA Astrophysics Data System (ADS)

Darcie, Thomas E.; Doverspike, Robert; Zirngibl, Martin; Korotky, Steven K.

2005-02-01

Call for Papers: Convergence Convergence has become a popular theme in telecommunications, one that has broad implications across all segments of the industry. Continual evolution of technology and applications continues to erase lines between traditionally separate lines of business, with dramatic consequences for vendors, service providers, and consumers. Spectacular advances in all layers of optical networking-leading to abundant, dynamic, cost-effective, and reliable wide-area and local-area connections-have been essential drivers of this evolution. As services and networks continue to evolve towards some notion of convergence, the continued role of optical networks must be explored. One vision of convergence renders all information in a common packet (especially IP) format. This vision is driven by the proliferation of data services. For example, time-division multiplexed (TDM) voice becomes VoIP. Analog cable-television signals become MPEG bits streamed to digital set-top boxes. T1 or OC-N private lines migrate to Ethernet virtual private networks (VPNs). All these packets coexist peacefully within a single packet-routing methodology built on an optical transport layer that combines the flexibility and cost of data networks with telecom-grade reliability. While this vision is appealing in its simplicity and shared widely, specifics of implementation raise many challenges and differences of opinion. For example, many seek to expand the role of Ethernet in these transport networks, while massive efforts are underway to make traditional TDM networks more data friendly within an evolved but backward-compatible SDH/SONET (synchronous digital hierarchy and synchronous optical network) multiplexing hierarchy. From this common underlying theme follow many specific instantiations. Examples include the convergence at the physical, logical, and operational levels of voice and data, video and data, private-line and virtual private-line, fixed and mobile, and local and long-haul services. These trends have many consequences for consumers, vendors, and carriers. Faced with large volumes of low-margin data traffic mixed with traditional voice services, the need for capital conservation and operational efficiency drives carriers away from today's separate overlay networks for each service and towards "converged" platforms. For example, cable operators require transport of multiple services over both hybrid fiber coax (HFC) and DWDM transport technologies. Local carriers seek an economical architecture to deliver integrated services on optically enabled broadband-access networks. Services over wireless-access networks must coexist with those from wired networks. In each case, convergence of networks and services inspires an important set of questions and challenges, driven by the need for low cost, operational efficiency, service performance requirements, and optical transport technology options. This Feature Issue explores the various interpretations and implications of network convergence pertinent to optical networking. How does convergence affect the evolution of optical transport-layer and control approaches? Are the implied directions consistent with research vision for optical networks? Substantial challenges remain. Papers are solicited across the broad spectrum of interests. These include, but are not limited to:

Convergence

NASA Astrophysics Data System (ADS)

Darcie, Thomas E.; Doverspike, Robert; Zirngibl, Martin; Korotky, Steven K.

2005-03-01

Call for Papers: Convergence Convergence has become a popular theme in telecommunications, one that has broad implications across all segments of the industry. Continual evolution of technology and applications continues to erase lines between traditionally separate lines of business, with dramatic consequences for vendors, service providers, and consumers. Spectacular advances in all layers of optical networking-leading to abundant, dynamic, cost-effective, and reliable wide-area and local-area connections-have been essential drivers of this evolution. As services and networks continue to evolve towards some notion of convergence, the continued role of optical networks must be explored. One vision of convergence renders all information in a common packet (especially IP) format. This vision is driven by the proliferation of data services. For example, time-division multiplexed (TDM) voice becomes VoIP. Analog cable-television signals become MPEG bits streamed to digital set-top boxes. T1 or OC-N private lines migrate to Ethernet virtual private networks (VPNs). All these packets coexist peacefully within a single packet-routing methodology built on an optical transport layer that combines the flexibility and cost of data networks with telecom-grade reliability. While this vision is appealing in its simplicity and shared widely, specifics of implementation raise many challenges and differences of opinion. For example, many seek to expand the role of Ethernet in these transport networks, while massive efforts are underway to make traditional TDM networks more data friendly within an evolved but backward-compatible SDH/SONET (synchronous digital hierarchy and synchronous optical network) multiplexing hierarchy. From this common underlying theme follow many specific instantiations. Examples include the convergence at the physical, logical, and operational levels of voice and data, video and data, private-line and virtual private-line, fixed and mobile, and local and long-haul services. These trends have many consequences for consumers, vendors, and carriers. Faced with large volumes of low-margin data traffic mixed with traditional voice services, the need for capital conservation and operational efficiency drives carriers away from today's separate overlay networks for each service and towards "converged" platforms. For example, cable operators require transport of multiple services over both hybrid fiber coax (HFC) and DWDM transport technologies. Local carriers seek an economical architecture to deliver integrated services on optically enabled broadband-access networks. Services over wireless-access networks must coexist with those from wired networks. In each case, convergence of networks and services inspires an important set of questions and challenges, driven by the need for low cost, operational efficiency, service performance requirements, and optical transport technology options. This Feature Issue explores the various interpretations and implications of network convergence pertinent to optical networking. How does convergence affect the evolution of optical transport-layer and control approaches? Are the implied directions consistent with research vision for optical networks? Substantial challenges remain. Papers are solicited across the broad spectrum of interests. These include, but are not limited to:

S-net : Construction of large scale seafloor observatory network for tsunamis and earthquakes along the Japan Trench

NASA Astrophysics Data System (ADS)

Mochizuki, M.; Uehira, K.; Kanazawa, T.; Shiomi, K.; Kunugi, T.; Aoi, S.; Matsumoto, T.; Sekiguchi, S.; Yamamoto, N.; Takahashi, N.; Nakamura, T.; Shinohara, M.; Yamada, T.

2017-12-01

NIED has launched the project of constructing a seafloor observatory network for tsunamis and earthquakes after the occurrence of the 2011 Tohoku Earthquake to enhance reliability of early warnings of tsunamis and earthquakes. The observatory network was named "S-net". The S-net project has been financially supported by MEXT.The S-net consists of 150 seafloor observatories which are connected in line with submarine optical cables. The total length of submarine optical cable is about 5,500 km. The S-net covers the focal region of the 2011 Tohoku Earthquake and its vicinity regions. Each observatory equips two units of a high sensitive pressure gauges as a tsunami meter and four sets of three-component seismometers. The S-net is composed of six segment networks. Five of six segment networks had been already installed. Installation of the last segment network covering the outer rise area have been finally finished by the end of FY2016. The outer rise segment has special features like no other five segments of the S-net. Those features are deep water and long distance. Most of 25 observatories on the outer rise segment are located at the depth of deeper than 6,000m WD. Especially, three observatories are set on the seafloor of deeper than about 7.000m WD, and then the pressure gauges capable of being used even at 8,000m WD are equipped on those three observatories. Total length of the submarine cables of the outer rise segment is about two times longer than those of the other segments. The longer the cable system is, the higher voltage supply is needed, and thus the observatories on the outer rise segment have high withstanding voltage characteristics. We employ a dispersion management line of a low loss formed by combining a plurality of optical fibers for the outer rise segment cable, in order to achieve long-distance, high-speed and large-capacity data transmission Installation of the outer rise segment was finished and then full-scale operation of S-net has started. All the data from 150 seafloor observatories are being transferred to and stored in the Tsukuba DC. Some data are being transmitted directly to JMA and have been used for monitoring of earthquakes and tsunamis. We will report construction and operation of the S-net system as well as the outline of the obtained data in this presentation.