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Sample records for scale cable fire

  1. Fully predictive simulation of real-scale cable tray fire based on small-scale laboratory experiments

    Energy Technology Data Exchange (ETDEWEB)

    Beji, Tarek; Merci, Bart [Ghent Univ. (Belgium). Dept. of Flow, Heat and Combustion Mechanics; Bonte, Frederick [Bel V, Brussels (Belgium)

    2015-12-15

    This paper presents a computational fluid dynamics (CFD)-based modelling strategy for real-scale cable tray fires. The challenge was to perform fully predictive simulations (that could be called 'blind' simulations) using solely information from laboratory-scale experiments, in addition to the geometrical arrangement of the cables. The results of the latter experiments were used (1) to construct the fuel molecule and the chemical reaction for combustion, and (2) to estimate the overall pyrolysis and burning behaviour. More particularly, the strategy regarding the second point consists of adopting a surface-based pyrolysis model. Since the burning behaviour of each cable could not be tracked individually (due to computational constraints), 'groups' of cables were modelled with an overall cable surface area equal to the actual value. The results obtained for one large-scale test (a stack of five horizontal trays) are quite encouraging, especially for the peak Heat Release Rate (HRR) that was predicted with a relative deviation of 3 %. The time to reach the peak is however overestimated by 4.7 min (i.e. 94 %). Also, the fire duration is overestimated by 5 min (i.e. 24 %). These discrepancies are mainly attributed to differences in the HRRPUA (heat release rate per unit area) profiles between the small-scale and large-scale. The latter was calculated by estimating the burning area of cables using video fire analysis (VFA).

  2. Cable fire tests in France

    Energy Technology Data Exchange (ETDEWEB)

    Kaercher, M. [Electricite de France (EDF), 69 - Villeurbanne (France)

    2000-05-01

    Modifications are being carried out in all French nuclear power plants to improve fire safety. These modifications are based on a three level defense in depth concept: fire preventing, fire containing and fire controlling. Fire containing requires many modifications such as protection of cable races and assessment of fire propagation which both need R and D development. On one hand, cable wraps made with mineral wool were tested in all configurations including effect of aging, overheating and fire and qualified for the use as protection from common failure modes. On the other hand, cables races in scale one were subject to gas burner or solvent pool fire to simulate ignition and fire propagation between trays and flash over situations. These tests have been performed under several typical lay out conditions. The results of the tests can be used as input data in computer modelling for validation of fire protection measures. (orig.) [German] Modifikationen werden in allen franzoesischen Kernkraftwerken durchgefuehrt, um die Brandschutzsicherung zu verbessern. Die Modifikationen sind auf einem Dreistufenkonzept begruendet: brandvorbeugende Massnahmen, begrenzter Brandschutz und Brandkontrolle. Begrenzter Brandschutz verlangt viele Modifikationen wie Brandschutz von Kabelanlagen und Kenntnisse ueber Feuerentwicklung, die Forschung und Entwicklung brauchen. Einerseits werden die aus Mineralwolle hergestellten Kabelhuellen fuer alle moeglichen Faelle geprueft, einschliesslich der Auswirkung von Alterung, Ueberhitzung und Feuer, um so die Huellen als Schutz zu nutzen. Andererseits werden Kabelanlagen der Stufe eins mit Gas und Loesungsmitteln entzuendet, um Entzuendung, Feuerentwicklung und Feueruebersprung zu simulieren. Diese Versuche werden unter unterschiedlichen Anlagenbedingungen durchgefuehrt. Die Ergebnisse koennen fuer Computermodelle zur Pruefung von Brandschutztechniken benutzt werden. (orig.)

  3. Cable fire risk of a nuclear power plant; Ydinvoimalaitoksen kaapelipaloriski

    Energy Technology Data Exchange (ETDEWEB)

    Aulamo, H.

    1998-02-01

    The aim of the study is to carry out a comprehensive review of cable fire risk issues of nuclear power plants (NPP) taking into account latest fire and risk assessment research results. A special emphasis is put on considering the fire risk analysis of cable rooms in the framework of TVO Olkiluoto NPP probabilistic safety assessment. The assumptions made in the analysis are assessed. The literature study section considers significant fire events at nuclear power plants, the most severe of which have nearly led to a reactor core damage (Browns Ferry, Greifswald, Armenia, Belojarsk, Narora). Cable fire research results are also examined. 62 refs.

  4. Response of Nuclear Power Plant Instrumentation Cables Exposed to Fire Conditions.

    Energy Technology Data Exchange (ETDEWEB)

    Muna, Alice Baca [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); LaFleur, Chris Bensdotter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brooks, Dusty Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    This report presents the results of instrumentation cable tests sponsored by the US Nuclear Regulatory Commission (NRC) Office of Nuclear Regulatory Research and performed at Sandia National Laboratories (SNL). The goal of the tests was to assess thermal and electrical response behavior under fire-exposure conditions for instrumentation cables and circuits. The test objective was to assess how severe radiant heating conditions surrounding an instrumentation cable affect current or voltage signals in an instrumentation circuit. A total of thirty-nine small-scale tests were conducted. Ten different instrumentation cables were tested, ranging from one conductor to eight-twisted pairs. Because the focus of the tests was thermoset (TS) cables, only two of the ten cables had thermoplastic (TP) insulation and jacket material and the remaining eight cables were one of three different TS insulation and jacket material. Two instrumentation cables from previous cable fire testing were included, one TS and one TP. Three test circuits were used to simulate instrumentation circuits present in nuclear power plants: a 4–20 mA current loop, a 10–50 mA current loop and a 1–5 VDC voltage loop. A regression analysis was conducted to determine key variables affecting signal leakage time.

  5. An enhanced fire hazard assessment model and validation experiments for vertical cable trays

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lu [Sate Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230027 (China); Huang, Xianjia, E-mail: huangxianjia@gziit.ac.cn [Joint Laboratory of Fire Safety in Nuclear Power Plants, Institute of Industry Technology Guangzhou & Chinese Academy of Sciences, Guangzhou 511458 (China); Bi, Kun; Liu, Xiaoshuang [China Nuclear Power Design Co., Ltd., Shenzhen 518045 (China)

    2016-05-15

    Highlights: • An enhanced model was developed for vertical cable fire hazard assessment in NPP. • The validated experiments on vertical cable tray fires were conducted. • The capability of the model for cable tray with different cable spacing were tested. - Abstract: The model, referred to as FLASH-CAT (Flame Spread over Horizontal Cable Trays), was developed to estimate the heat release rate for vertical cable tray fire. The focus of this work is to investigate the application of an enhanced model to the single vertical cable tray fires with different cable spacing. The experiments on vertical cable tray fires with three typical cable spacing were conducted. The histories of mass loss rate and flame length were recorded during the cable fire. From the experimental results, it is found that the space between cable lines intensifies the cable combustion and accelerates the flame spread. The predictions by the enhanced model show good agreements with the experimental data. At the same time, it is shown that the enhanced model is capable of predicting the different behaviors of cable fires with different cable spacing by adjusting the flame spread speed only.

  6. Assessment of the burning behavior of protected and unprotected cables and cable trays in nuclear installations using small- and large-scale experiments

    Energy Technology Data Exchange (ETDEWEB)

    Siemon, Matthias; Riese, Olaf; Zehfuss, Jochen [Technische Univ. Braunschweig (Germany). Inst. fuer Baustoffe, Massivbau und Brandschutz (iBMB)

    2015-12-15

    Electric installations and cables are a main fire risk source in industrial buildings and power plants. In general, cables and cable systems are associated with flash-over phenomena due to pyrolysis of fuel gases induced by the heat of an adjacent fire, fire spread along cable trays affecting additional areas besides the fire origin, being an ignition source due to malfunction. If burning, cables can emit large amounts of smoke and toxic products affecting occupants as well as the long-term functionality of structure and installations. Paying attention to these risks has led to the development of fire retardant non-corrosive (non-halogenated) cables which are qualified to reduce the individual or all of the risks mentioned. For existing installations in industrial buildings and power plants with halogenated cables, different protection measures are available and widely applied retroactively. Important protective measures are intumescent or ablative coatings, cable casings and bindings. For qualification of the effects of the protection measures, small-scale tests investigating a single cable specimen as well as large-scale cable tray test setups have been developed and carried out in the last 20 years at iBMB. In this paper, these test results are analysed regarding their effects on the heat release, ignition time and fire spread over cable trays. Furthermore, national and international research projects have investigated the burning behaviour of different cable types, tray installations, tray loading and spacing and ventilation conditions. As a conclusion, the main outcomes of past researches are summarized. Influence factors (e.g. pre-heating due to high power utilization, influence of cable aging) which have not been accounted for in detail are emphasized. The modelling of unprotected cables has been internationally studied in recent years. For future applications, the question of applicability of recently developed sub-models on the fire behaviour of protected

  7. Investigations on fire behavior of cable devices and to protect insulating coatings on cables; Untersuchungen zum Brandverhalten von Kabelanlagen und zur Schutzfunktion von daemmschichtbildenden Anstrichen auf Kabeln

    Energy Technology Data Exchange (ETDEWEB)

    Hosser, D.; Siegfried, W.; Will, J.

    1998-02-01

    Cable constructions to supply and control electric installations may represent a considerable risk potential in case of a fire for buildings with a high level of installations. On the one hand, flammable cable insulation materials themselves can induce a fire. On the other hand cables are often installed over long distances, therefore a fire and flame spreading along the cables is possible. Intumescent and ablative coatings, which were developed to reduce the risk of initial fires as well as the fire propagation and to restrict the impact of fires, are increasingly used in power plants as protective measures for cable lines. Since 1994, a large number of fire tests have been carried out for unprotected as well as protected PVC cables at iBMB of TU Braunschweig. To answer the questions, which have occurred in the frame of these experiments, extensive series of small-scale and real-scale tests are necessary to be carried out. As a result of these investigations commons and differences in the burning behaviour of electric cables, depending on type of cable, package density and orientation, are presented in form of the physical parameters heat release rate, heat of combustion, flame spread velocity and release of toxic products. The difference between accepted standardised test procedures and the selected experimental approach are discussed. The results of these tests give support to assessing the fire risk of unprotected as well as protected PVC cables under typical operating conditions. (orig.) [Deutsch] Kabelanlagen zur Versorgung und Steuerung von elektrischen Anlagen koennen in Gebaeuden mit hohem Installationsgrad ein erhebliches Gefahrenpotential im Brandfall darstellen, wobei die elektrischen Leitungen einerseits selbst die Ursache eines Feuers sein koennen, anderseits aber auch durch ihre oftmals ueber grosse Abschnitte verlaufende Verlegung die Brandausbreitung foerdern. Zur Verringerung des Brandentstehungs- und Brandausbreitungsrisikos durch elektrische

  8. Ventilation Controlled Fires: Smoke Obscuration and Venting in Cable Fire Tests

    Science.gov (United States)

    1981-02-01

    with the vigor exhibited prior to the first water application. 3.2 Smoke Ventilation Three ventilation situations were explored. 0 Smoke control during...5.0 Conclusions This year efforts focused on smoke control in cable fires. Conse- quently, the experimental variables were limited to (a) one type of... Smoke control by an extemporaneous hole opened directly above the fire (Pattern G) was very effective in clearing the compartment; how- ever, it should be

  9. Modeling of Electrical Cable Failure in a Dynamic Assessment of Fire Risk

    Science.gov (United States)

    Bucknor, Matthew D.

    Fires at a nuclear power plant are a safety concern because of their potential to defeat the redundant safety features that provide a high level of assurance of the ability to safely shutdown the plant. One of the added complexities of providing protection against fires is the need to determine the likelihood of electrical cable failure which can lead to the loss of the ability to control or spurious actuation of equipment that is required for safe shutdown. A number of plants are now transitioning from their deterministic fire protection programs to a risk-informed, performance based fire protection program according to the requirements of National Fire Protection Association (NFPA) 805. Within a risk-informed framework, credit can be taken for the analysis of fire progression within a fire zone that was not permissible within the deterministic framework of a 10 CFR 50.48 Appendix R safe shutdown analysis. To perform the analyses required for the transition, plants need to be able to demonstrate with some level of assurance that cables related to safe shutdown equipment will not be compromised during postulated fire scenarios. This research contains the development of new cable failure models that have the potential to more accurately predict electrical cable failure in common cable bundle configurations. Methods to determine the thermal properties of the new models from empirical data are presented along with comparisons between the new models and existing techniques used in the nuclear industry today. A Dynamic Event Tree (DET) methodology is also presented which allows for the proper treatment of uncertainties associated with fire brigade intervention and its effects on cable failure analysis. Finally a shielding analysis is performed to determine the effects on the temperature response of a cable bundle that is shielded from a fire source by an intervening object such as another cable tray. The results from the analyses demonstrate that models of similar

  10. Large-scale pool fires

    Directory of Open Access Journals (Sweden)

    Steinhaus Thomas

    2007-01-01

    Full Text Available A review of research into the burning behavior of large pool fires and fuel spill fires is presented. The features which distinguish such fires from smaller pool fires are mainly associated with the fire dynamics at low source Froude numbers and the radiative interaction with the fire source. In hydrocarbon fires, higher soot levels at increased diameters result in radiation blockage effects around the perimeter of large fire plumes; this yields lower emissive powers and a drastic reduction in the radiative loss fraction; whilst there are simplifying factors with these phenomena, arising from the fact that soot yield can saturate, there are other complications deriving from the intermittency of the behavior, with luminous regions of efficient combustion appearing randomly in the outer surface of the fire according the turbulent fluctuations in the fire plume. Knowledge of the fluid flow instabilities, which lead to the formation of large eddies, is also key to understanding the behavior of large-scale fires. Here modeling tools can be effectively exploited in order to investigate the fluid flow phenomena, including RANS- and LES-based computational fluid dynamics codes. The latter are well-suited to representation of the turbulent motions, but a number of challenges remain with their practical application. Massively-parallel computational resources are likely to be necessary in order to be able to adequately address the complex coupled phenomena to the level of detail that is necessary.

  11. Cross-scale analysis of fire regimes

    Science.gov (United States)

    Donald A. Falk; Carol Miller; Donald McKenzie; Anne E. Black

    2007-01-01

    Cross-scale spatial and temporal perspectives are important for studying contagious landscape disturbances such as fire, which are controlled by myriad processes operating at different scales. We examine fire regimes in forests of western North America, focusing on how observed patterns of fire frequency change across spatial scales. To quantify changes in fire...

  12. Effect of oxygen concentration on fire growth of various types of cable bending in horizontal and vertical orientations

    Science.gov (United States)

    Pangaribuan, Adrianus; Dhiputra, I. M. K.; Nugroho, Yulianto S.

    2017-03-01

    Electrical cable is a whole of the material including metal (cooper) conductor and its insulation, when an electrical cable is flowed by electric current, based on its own capacity, the temperature of cable conductor increases gradually. If the current flows above the cable carrying capacity, then an extreme temperature rises are expected. When temperature increase, the electric current flow inside cable conductor will decrease gradually related to the resistance and could occur repeatedly in a period. Since electrical faults on electrical cable system are often suspected as the cause of fires, thus this research aims to investigate measures of preventing the fire to start by means of controlling oxygen concentration in a cable compartment. The experimental work was conducted in laboratory by using electrical power cable of 1.5 mm2 size. Two transparent chambers were applied for studying the effect of vertical and horizontal orientations on the cable temperature rise, under various oxygen concentration of the gas streams. In the present work, the electrical was maintained at a constant level during a typical test run. Parametric studies reported in the paper include the use of a bare and insulated cables as well as the bending shape of the cable lines of a straight cable, coiled cable and randomly bent cable which were loaded with the same electric load and oxygen concentration in the gas supply.

  13. Dynamically Scaled Model Experiment of a Mooring Cable

    Directory of Open Access Journals (Sweden)

    Lars Bergdahl

    2016-01-01

    Full Text Available The dynamic response of mooring cables for marine structures is scale-dependent, and perfect dynamic similitude between full-scale prototypes and small-scale physical model tests is difficult to achieve. The best possible scaling is here sought by means of a specific set of dimensionless parameters, and the model accuracy is also evaluated by two alternative sets of dimensionless parameters. A special feature of the presented experiment is that a chain was scaled to have correct propagation celerity for longitudinal elastic waves, thus providing perfect geometrical and dynamic scaling in vacuum, which is unique. The scaling error due to incorrect Reynolds number seemed to be of minor importance. The 33 m experimental chain could then be considered a scaled 76 mm stud chain with the length 1240 m, i.e., at the length scale of 1:37.6. Due to the correct elastic scale, the physical model was able to reproduce the effect of snatch loads giving rise to tensional shock waves propagating along the cable. The results from the experiment were used to validate the newly developed cable-dynamics code, MooDy, which utilises a discontinuous Galerkin FEM formulation. The validation of MooDy proved to be successful for the presented experiments. The experimental data is made available here for validation of other numerical codes by publishing digitised time series of two of the experiments.

  14. Low smoke, non-corrosive, fire retardant cable jackets based on HNBR and EVM

    Energy Technology Data Exchange (ETDEWEB)

    Meisenheimer, H.

    1991-06-01

    This article examines the properties of the polymers HNBR and EVM which make them good candidates for use in meeting the low smoke, non-corrosive, low toxicity and fire retardant requirements for electric safety cable jackets and electric insulation. Topics of the article include density, weight, and viscosity of each polymer, mechanical proprieties of each polymer, and other results of laboratory testing of these polymers.

  15. Fire structures pine serotiny at different scales.

    Science.gov (United States)

    Hernández-Serrano, Ana; Verdú, Miguel; González-Martínez, Santiago C; Pausas, Juli G

    2013-12-01

    Serotiny (delayed seed release with the consequent accumulation of a canopy seedbank) confers fitness benefits in environments with crown-fire regimes. Thus, we predicted that serotiny level should be higher in populations recurrently subjected to crown-fires than in populations where crown-fires are rare. In addition, under a high frequency of fires, space and resources are recurrently available, permitting recruitment around each mother to follow the seed rain shadow. Thus, we also predicted spatial aggregation of serotiny within populations. We compared serotiny, considering both the proportion and the age of serotinous cones, in populations living in contrasting fire regimes for two iconic Mediterranean pine species (Pinus halepensis, P. pinaster). We framed our results by quantitatively comparing the strength of the fire-serotiny relationship with previous studies worldwide. For the two species, populations living under high crown-fire recurrence regimes had a higher serotiny level than those populations where the recurrence of crown-fires was low. For P. halepensis (the species with higher serotiny), populations in high fire recurrence regimes had higher fine-scale spatial aggregation of serotiny than those inhabiting low fire recurrence systems. The strength of the observed fire-serotiny relationship in P. halepensis is among the highest in published literature. Fire regime shapes serotiny level among populations, and in populations with high serotiny, recurrent fires maintain a significant spatial structure for this trait. Consequently, fire has long-term evolutionary implications at different scales, emphasizing its prominent role in shaping the ecology of pines.

  16. Determination of cable parameters in skeletal muscle fibres during repetitive firing of action potentials

    Science.gov (United States)

    Riisager, Anders; Duehmke, Rudy; Nielsen, Ole Bækgaard; Huang, Christopher L; Pedersen, Thomas Holm

    2014-01-01

    Recent studies in rat muscle fibres show that repetitive firing of action potentials causes changes in fibre resting membrane conductance (Gm) that reflect regulation of ClC-1 Cl− and KATP K+ ion channels. Methodologically, these findings were obtained by inserting two microelectrodes at close proximity in the same fibres enabling measurements of fibre input resistance (Rin) in between action potential trains. Since the fibre length constant (λ) could not be determined, however, the calculation of Gm relied on the assumptions that the specific cytosolic resistivity (Ri) and muscle fibre volume remained constant during the repeated action potential firing. Here we present a three-microelectrode technique that enables determinations of multiple cable parameters in action potential-firing fibres including Rin and λ as well as waveform and conduction velocities of fully propagating action potentials. It is shown that in both rat and mouse extensor digitorum longus (EDL) fibres, action potential firing leads to substantial changes in both muscle fibre volume and Ri. The analysis also showed, however, that regardless of these changes, rat and mouse EDL fibres both exhibited initial decreases in Gm that were eventually followed by a ∼3-fold, fully reversible increase in Gm after the firing of 1450–1800 action potentials. Using this three-electrode method we further show that the latter rise in Gm was closely associated with excitation failures and loss of action potential signal above −20 mV. PMID:25128573

  17. HTS cables open the window for large-scale renewables

    Science.gov (United States)

    Geschiere, A.; Willén, D.; Piga, E.; Barendregt, P.

    2008-02-01

    In a realistic approach to future energy consumption, the effects of sustainable power sources and the effects of growing welfare with increased use of electricity need to be considered. These factors lead to an increased transfer of electric energy over the networks. A dominant part of the energy need will come from expanded large-scale renewable sources. To use them efficiently over Europe, large energy transits between different countries are required. Bottlenecks in the existing infrastructure will be avoided by strengthening the network. For environmental reasons more infrastructure will be built underground. Nuon is studying the HTS technology as a component to solve these challenges. This technology offers a tremendously large power transport capacity as well as the possibility to reduce short circuit currents, making integration of renewables easier. Furthermore, power transport will be possible at lower voltage levels, giving the opportunity to upgrade the existing network while re-using it. This will result in large cost savings while reaching the future energy challenges. In a 6 km backbone structure in Amsterdam Nuon wants to install a 50 kV HTS Triax cable for a significant increase of the transport capacity, while developing its capabilities. Nevertheless several barriers have to be overcome.

  18. Instrumentation Cables Test Plan

    Energy Technology Data Exchange (ETDEWEB)

    Muna, Alice Baca [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); LaFleur, Chris Bensdotter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-10-01

    and fluctuate, while the thermoplastic insulated cables, the instrument reading fell off-scale rapidly. From an operational point of view, the latter failure characteristics would likely be identified as a failure from the effects of fire, while the former may result in inaccurate readings.

  19. Large Scale Experiments on Spacecraft Fire Safety

    DEFF Research Database (Denmark)

    Urban, David L.; Ruff, Gary A.; Minster, Olivier

    2012-01-01

    Full scale fire testing complemented by computer modelling has provided significant knowhow about the risk, prevention and suppression of fire in terrestrial systems (cars, ships, planes, buildings, mines, and tunnels). In comparison, no such testing has been carried out for manned spacecraft due......-based microgravity facilities or has been limited to very small fuel samples. Still, the work conducted to date has shown that fire behaviour in low-gravity is very different from that in normal-gravity, with differences observed for flammability limits, ignition delay, flame spread behaviour, flame colour and flame...

  20. Optimal Selection of AC Cables for Large Scale Offshore Wind Farms

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Chen, Zhe

    2014-01-01

    The investment of large scale offshore wind farms is high in which the electrical system has a significant contribution to the total cost. As one of the key components, the cost of the connection cables affects the initial investment a lot. The development of cable manufacturing provides a vast...... choice space and a great opportunity to optimize the system cost while meets the operational requirements of the offshore wind farms and the connected power systems. In this paper, a new cost model for AC-cable is proposed and the optimal cable selection framework is established using the optimization...... platform in Matlab. A real offshore wind farm is chosen as the study case to demonstrate the proposed method. Furthermore, the optimization is also applied to an offshore wind farm under development. It can be observed from the results that the proposed optimal cable selection framework is an efficient...

  1. Circuit bridging of digital equipment caused by smoke from a cable fire

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, T.J.; Anderson, D.J.

    1997-03-01

    Advanced reactor systems are likely to use protection systems with digital electronics that ideally should be resistant to environmental hazards, including smoke from possible cable fires. Previous smoke tests have shown that digital safety systems can fail even at relatively low levels of smoke density and that short-term failures are likely to be caused by circuit bridging. Experiments were performed to examine these failures, with a focus on component packaging and protection schemes. Circuit bridging, which causes increased leakage currents and arcs, was gauged by measuring leakage currents among the leads of component packages. The resistance among circuit leads typically varies over a wide range, depending on the nature of the circuitry between the pins, bias conditions, circuit board material, etc. Resistance between leads can be as low as 20 k{Omega} and still be good, depending on the component. For these tests, the authors chose a printed circuit board and components that normally have an interlead resistance above 10{sup 12} {Omega}, but if the circuit is exposed to smoke, circuit bridging causes the resistance to fall below 10{sup 3} {Omega}. Plated-through-hole (PTH) and surface-mounted (SMT) packages were exposed to a series of different smoke environments using a mixture of environmentally qualified cables for fuel. Conformal coatings and enclosures were tested as circuit protection methods. High fuel levels, high humidity, and high flaming burns were the conditions most likely to cause circuit bridging. The inexpensive conformal coating that was tested - an acrylic spray - reduced leakage currents, but enclosure in a chassis with a fan did not. PTH packages were more resistant to smoke-induced circuit bridging than SMT packages. Active components failed most often in tests where the leakage currents were high, but failure did not always accompany high leakage currents.

  2. Small Scale Hydrocarbon Fire Test Concept

    Directory of Open Access Journals (Sweden)

    Joachim Søreng Bjørge

    2017-11-01

    Full Text Available In the oil and gas industry, hydrocarbon process equipment was previously often thermally insulated by applying insulation directly to the metal surface. Fire protective insulation was applied outside the thermal insulation. In some cases, severe corrosion attacks were observed due to ingress of humidity and condensation at cold surfaces. Introducing a 25 mm air gap to prevent wet thermal insulation and metal wall contact is expected to solve the corrosion issues. This improved insulation methodology does, however, require more space that may not be available when refurbishing older process plants. Relocating structural elements would introduce much hot work, which should be minimized in live plants. It is also costly. The aim of the present study is therefore to develop a test concept for testing fire resistance of equipment protected with only air-gap and thermal insulation, i.e., without the fire-protective insulation. The present work demonstrates a conceptual methodology for small scale fire testing of mockups resembling a section of a distillation column. The mockups were exposed to a small-scale propane flame in a test configuration where the flow rate and the flame zone were optimized to give heat flux levels in the range 250–350 kW/m2. Results are presented for a mockup resembling a 16 mm thick distillation column steel wall. It is demonstrated that the modern distance insulation in combination with the heat capacity of the column wall indicates 30+ minutes fire resistance. The results show that this methodology has great potentials for low cost fire testing of other configurations, and it may serve as a set-up for product development.

  3. MIC-Large Scale Magnetically Inflated Cable Structures for Space Power, Propulsion, Communications and Observational Applications

    Science.gov (United States)

    Powell, James; Maise, George; Rather, John

    2010-01-01

    A new approach for the erection of rigid large scale structures in space-MIC (Magnetically Inflated Cable)-is described. MIC structures are launched as a compact payload of superconducting cables and attached tethers. After reaching orbit, the superconducting cables are energized with electrical current. The magnet force interactions between the cables cause them to expand outwards into the final large structure. Various structural shapes and applications are described. The MIC structure can be a simple flat disc with a superconducting outer ring that supports a tether network holding a solar cell array, or it can form a curved mirror surface that concentrates light and focuses it on a smaller region-for example, a high flux solar array that generates electric power, a high temperature receiver that heats H2 propellant for high Isp propulsion, and a giant primary reflector for a telescope for astronomy and Earth surveillance. Linear dipole and quadrupole MIC structures are also possible. The linear quadrupole structure can be used for magnetic shielding against cosmic radiation for astronauts, for example. MIC could use lightweight YBCO superconducting HTS (High Temperature Superconductor) cables, that can operate with liquid N2 coolant at engineering current densities of ~105 amp/cm2. A 1 kilometer length of MIC cable would weigh only 3 metric tons, including superconductor, thermal insulations, coolant circuits, and refrigerator, and fit within a 3 cubic meter compact package for launch. Four potential MIC applications are described: Solar-thermal propulsion using H2 propellant, space based solar power generation for beaming power to Earth, a large space telescope, and solar electric generation for a manned lunar base. The first 3 applications use large MIC solar concentrating mirrors, while the 4th application uses a surface based array of solar cells on a magnetically levitated MIC structure to follow the sun. MIC space based mirrors can be very large and light

  4. VdS technical meeting: fire protection as applied to cable systems; VdS-Fachtagung: Brandschutz in Kabelanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Wendl, H. (comp.)

    2001-07-01

    Vds regulations and specifications are based on experience in real cases of damage. Fire protection systems offer reliable protection against destruction of cable systems and failure of electric systems. The economic aspects of fire protection were discussed at the meeting. [German] Die Schadenerfahrungen und Erkenntnisse aus der Gefahrenabwehr finden ihren Niederschlag in VdS-Richtlinien und -Merkblaettern. Das VdS-Regelwerk schliesst Luecken in anderen technischen Regelwerken oder ist auf neu erkannte Gefahren abgestellt, die in Normen oder anderen technischen Regelwerken noch nicht behandelt worden sind. Brandschutz in Kabelanlagen gewaehrleistet bei ordnungsgemaesser Ausfuehrung und Einhaltung der bautechnischen Anforderungen zuverlaessigen Schutz gegen Zerstoerung der Kabelanlagen und Ausfall der elektrischen Energie. Die Moeglichkeiten, Brandschutz auch unter wirtschaftlichen Gesichtspunkten zu realisieren, wurden in dieser Fachtagung mit aktuellen Themen und anhand ausgewwahlter Beispiele dargelegt. (orig.)

  5. Fire-resisting painting. Qualification and application of insulating coatings of cables; Farbe kontra Feuer. Qualifizierung und Anwendung von daemmschichtbildenden Beschichtungen auf Kabelanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Will, J.; Hosser, D. [Technische Univ. Braunschweig (Germany). Inst. fuer Baustoffe, Massivbau und Brandschutz

    1999-11-01

    Extensive investigations of coated and uncoated PVC cables showed a qualitative and quantitative effect of coatings in terms of fire protection. The method employed is suited as a qualifaication method which is compared with accepted test methods for low-inflammable constructional materials (DIN 4102-1) or electric cables with improved fire resistance (DIN VDE 0472-804). Cables and cable coatings meeting the requirements of the qualification method have a higher safety level and thus a wider range of applications. With this in mind, the authors discuss a new version of the standard for cable systems with a view to fire-resistant coatings. [German] In umfangreichen Untersuchungen an unbeschichteten und beschichteten PVC-Kabeln konnte eine erhebliche Reduzierung der Brandrisiken durch Anwendung von Daemmschichtbildern als Kabelschutzsystem qualitativ und quantitativ nachgewiesen werden. Die dabei angewandte Vorgehensweise eignet sich als Qualifizierungsverfahren, das mit anerkannten Pruefverfahren fuer schwerentflammbare Baustoffe (DIN 4102-1) oder elektrische Kabel mit verbessertem Brandverhalten (DIN VDE 0472-804) verglichen wird. Aufgrund des Vergleichs der Pruefverfahren, aber auch des Brandverhaltens von beschichteten Kabeln bei den unterschiedlichen Untersuchungsbedingungen ergibt sich ein hoeheres Sicherheitsniveau und damit zusaetzliche Anwendungsgebiete fuer elektrische Kabel und Kabelbeschichtungen, die die Kriterien des Qualifizierungsverfahrens erfuellen. Unter diesem Gesichtspunkt wird die neue Fassung der Musterrichtlinie fuer Leitungsanlagen in Bezug auf die Anwendung von Brandschutzbeschichtungen auf Kabeln diskutiert. (orig.)

  6. Use of Distributed Temperature Sensing Technology to Characterize Fire Behavior

    Directory of Open Access Journals (Sweden)

    Douglas Cram

    2016-10-01

    Full Text Available We evaluated the potential of a fiber optic cable connected to distributed temperature sensing (DTS technology to withstand wildland fire conditions and quantify fire behavior parameters. We used a custom-made ‘fire cable’ consisting of three optical fibers coated with three different materials—acrylate, copper and polyimide. The 150-m cable was deployed in grasslands and burned in three prescribed fires. The DTS system recorded fire cable output every three seconds and integrated temperatures every 50.6 cm. Results indicated the fire cable was physically capable of withstanding repeated rugged use. Fiber coating materials withstood temperatures up to 422 °C. Changes in fiber attenuation following fire were near zero (−0.81 to 0.12 dB/km indicating essentially no change in light gain or loss as a function of distance or fire intensity over the length of the fire cable. Results indicated fire cable and DTS technology have potential to quantify fire environment parameters such as heat duration and rate of spread but additional experimentation and analysis are required to determine efficacy and response times. This study adds understanding of DTS and fire cable technology as a potential new method for characterizing fire behavior parameters at greater temporal and spatial scales.

  7. Development of the Database of Cables of Almaraz NPP as the fire deterministic analysis support; Elaboracion de la base de datos de cables de C.N. Almaraz como soporte de los analisis deterministas de incendios

    Energy Technology Data Exchange (ETDEWEB)

    Villar Sanchez, T.; Fernandez Ramos, P.; Garcia Romero, A.; Fuente Prieto, I.

    2013-07-01

    Within the process of transition to the NFPA-805, it requires a deterministic analysis of fire, for which it is necessary, on the one hand, the identification and location of the cables and equipment necessary and important for achieve and maintain safe, and stop on the other hand, the analysis of the different types of spurious multiple, based on the methodology described in the NEI 00-01 Rev. 2. the base Almaraz NPP cables data it collects this information and is a fundamental tool to analyze the capacity of the plant to achieve the stop safe in case of fire, which allows you to find possible vulnerabilities and take appropriate measures to improve the security of it.

  8. The Phoenix series large scale LNG pool fire experiments.

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, Richard B.; Jensen, Richard Pearson; Demosthenous, Byron; Luketa, Anay Josephine; Ricks, Allen Joseph; Hightower, Marion Michael; Blanchat, Thomas K.; Helmick, Paul H.; Tieszen, Sheldon Robert; Deola, Regina Anne; Mercier, Jeffrey Alan; Suo-Anttila, Jill Marie; Miller, Timothy J.

    2010-12-01

    The increasing demand for natural gas could increase the number and frequency of Liquefied Natural Gas (LNG) tanker deliveries to ports across the United States. Because of the increasing number of shipments and the number of possible new facilities, concerns about the potential safety of the public and property from an accidental, and even more importantly intentional spills, have increased. While improvements have been made over the past decade in assessing hazards from LNG spills, the existing experimental data is much smaller in size and scale than many postulated large accidental and intentional spills. Since the physics and hazards from a fire change with fire size, there are concerns about the adequacy of current hazard prediction techniques for large LNG spills and fires. To address these concerns, Congress funded the Department of Energy (DOE) in 2008 to conduct a series of laboratory and large-scale LNG pool fire experiments at Sandia National Laboratories (Sandia) in Albuquerque, New Mexico. This report presents the test data and results of both sets of fire experiments. A series of five reduced-scale (gas burner) tests (yielding 27 sets of data) were conducted in 2007 and 2008 at Sandia's Thermal Test Complex (TTC) to assess flame height to fire diameter ratios as a function of nondimensional heat release rates for extrapolation to large-scale LNG fires. The large-scale LNG pool fire experiments were conducted in a 120 m diameter pond specially designed and constructed in Sandia's Area III large-scale test complex. Two fire tests of LNG spills of 21 and 81 m in diameter were conducted in 2009 to improve the understanding of flame height, smoke production, and burn rate and therefore the physics and hazards of large LNG spills and fires.

  9. Study of special spacer with damping device for suppressing wake galloping in tandem cables of cable-stayed bridges and its application to full scale bridge; Nendanseitai wo riyoshita heiretsu cable yo gensui kinotsuki spacer to sono jikkyo cable eno tekiyo ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Yoneda, M.; Setouchi, H.; Yoshioka, A. [Kawada Industries Inc., Tokyo (Japan); Shimoda, I.; Kawahara, S. [Oiles Corp., Tokyo (Japan)

    1996-12-20

    Cable vibration called wake galloping occurs in a cable-stayed bridge, in which cables are arranged tandem, and suppression of the vibration is an extremely important discussion item. This paper describes a complex eigen value analysis performed on tandem cables having lengths of 200 m and 100 m. The analysis revealed that damping characteristics added by a spacer system with a damping device (a type to install a visco-elastic body at about middle of the tandem cables via a jig) depend largely on torsional rigidity of the cables; and the characteristics may vary with difference in intervals between cable centers and that in cable diameters. A visco-elastic damping material of an asphalt system and a spacer with a damping device used as a spring material were fabricated and applied to a full scale bridge to identify quantitatively the damping addition characteristics of this system. Furthermore, the results of tests on the full scale bridge were compared with the result of the complex eigen value analysis, from which findings useful for actual works were obtained. 18 refs., 17 figs., 6 tabs.

  10. Identification of aeroelastic forces on bridge cables from full-scale measurements

    DEFF Research Database (Denmark)

    Acampora, Antonio; Macdonald, J.H.G.; Georgakis, Christos

    2011-01-01

    Despite much research in recent years, large amplitude vibrations of inclined cables continue to be of concern for cable-stayed bridges. Various mechanisms have been suggested for their excitation, including rain-wind excitation, dry inclined cable galloping, high reduced velocity vortex shedding...... Bridge. The system records wind conditions and weather conditions, as well as accelerations of certain cables and a few locations on the deck and tower. Using state-of-the-art methods of output-only system identification, the vibration modes of the cables have been identified. From these modes...

  11. Scaling of the burning efficiency for multicomponent fuel pool fires

    DEFF Research Database (Denmark)

    van Gelderen, Laurens; Farahani, Hamed Farmahini; Rangwala, Ali S.

    must continuously increase to evaporate the heaviest components. Small scale experiments were deemed to lack a sufficient flame volume and resulting heat feedback to the fuel surface to reach such temperatures, thus explaining the lower burning efficiencies. Small scale experiments featuring...... an external heat source to simulate the larger fire size are currently in process....

  12. Full-scale measurements and system identification on Sutong cable-stayed bridge during Typhoon Fung-Wong.

    Science.gov (United States)

    Wang, Hao; Tao, Tianyou; Guo, Tong; Li, Jian; Li, Aiqun

    2014-01-01

    The structural health monitoring system (SHMS) provides an effective tool to conduct full-scale measurements on existing bridges for essential research on bridge wind engineering. In July 2008, Typhoon Fung-Wong lashed China and hit Sutong cable-stayed bridge (SCB) in China. During typhoon period, full-scale measurements were conducted to record the wind data and the structural vibration responses were collected by the SHMS installed on SCB. Based on the statistical method and the spectral analysis technique, the measured data are analyzed to obtain the typical parameters and characteristics. Furthermore, this paper analyzed the measured structural vibration responses and indicated the vibration characteristics of the stay cable and the deck, the relationship between structural vibrations and wind speed, the comparison of upstream and downstream cable vibrations, the effectiveness of cable dampers, and so forth. Considering the significance of damping ratio in vibration mitigation, the modal damping ratios of the SCB are identified based on the Hilbert-Huang transform (HHT) combined with the random decrement technique (RDT). The analysis results can be used to validate the current dynamic characteristic analysis methods, buffeting calculation methods, and wind tunnel test results of the long-span cable-stayed bridges.

  13. Full-Scale Measurements and System Identification on Sutong Cable-Stayed Bridge during Typhoon Fung-Wong

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2014-01-01

    Full Text Available The structural health monitoring system (SHMS provides an effective tool to conduct full-scale measurements on existing bridges for essential research on bridge wind engineering. In July 2008, Typhoon Fung-Wong lashed China and hit Sutong cable-stayed bridge (SCB in China. During typhoon period, full-scale measurements were conducted to record the wind data and the structural vibration responses were collected by the SHMS installed on SCB. Based on the statistical method and the spectral analysis technique, the measured data are analyzed to obtain the typical parameters and characteristics. Furthermore, this paper analyzed the measured structural vibration responses and indicated the vibration characteristics of the stay cable and the deck, the relationship between structural vibrations and wind speed, the comparison of upstream and downstream cable vibrations, the effectiveness of cable dampers, and so forth. Considering the significance of damping ratio in vibration mitigation, the modal damping ratios of the SCB are identified based on the Hilbert-Huang transform (HHT combined with the random decrement technique (RDT. The analysis results can be used to validate the current dynamic characteristic analysis methods, buffeting calculation methods, and wind tunnel test results of the long-span cable-stayed bridges.

  14. Explosive Concrete Spalling during Large-Scale Fire Resistance Tests

    OpenAIRE

    Maluk, Cristian; Bisby, Luke; Giovanni P. Terrasi

    2016-01-01

    This paper presents a comprehensive investigation of explosive heat-induced spalling observed during a set of large-scale fire resistance tests (or standard furnace tests) on prestressed concrete slabs. The study, based on data from large-scale tests, examines the influence of numerous design parameters in the occurrence of spalling (age of concrete, inclusion of polypropylene fibres, depth of the slab, and prestressing level). Furthermore, a careful thermal analysis of the tested slabs is pr...

  15. Full Scale Test on a 100km, 150kV AC Cable

    DEFF Research Database (Denmark)

    Faria da Silva, Filipe Farria; Wiechowski, W.; Bak, Claus Leth

    2010-01-01

    This paper presents some of the results obtained from the electrical measurements on a 99.7 km, 150 kV three-phase AC cable, connecting 215 MW offshore wind farm Horns Rev 2, located in Denmark west coast, to Denmark's 400 kV transmission network. The measurements were performed at nominal voltage......, but unusual in overhead lines. In this paper is made a characterization of the cable and the power transmission system in which the cable is installed, followed by a description of the measurement equipment and of the test setup/procedures. A theoretical explanation and presentation of different analysed...... phenomena is conducted. The cases analysed in this paper are: Zero-missing phenomenon, Ferranti effect, energisation transient, effect of the cable's connection in the busbar voltage and cable disconnection. For all the phenomena described in the paper measurement data are presented and it is verified...

  16. Development of Large-Scale Spacecraft Fire Safety Experiments

    DEFF Research Database (Denmark)

    Ruff, Gary A.; Urban, David L.; Fernandez-Pello, A. Carlos

    2013-01-01

    with the data downlinked at the conclusion of the test before the Cygnus vehicle reenters the atmosphere. Several computer modeling and ground-based experiment efforts will complement the flight experiment effort. The international topical team is collaborating with the NASA team in the definition...... of the spacecraft fire safety risk. The activity of this project is supported by an international topical team of fire experts from other space agencies who conduct research that is integrated into the overall experiment design. The large-scale space flight experiment will be conducted in an Orbital Sciences...

  17. Interannual variations in fire weather, fire extent, and synoptic-scale circulation patterns in northern California and Oregon

    Science.gov (United States)

    Trouet, Valerie; Taylor, Alan H.; Carleton, Andrew M.; Skinner, Carl N.

    2009-03-01

    The Mediterranean climate region on the west coast of the United States is characterized by wet winters and dry summers, and by high fire activity. The importance of synoptic-scale circulation patterns (ENSO, PDO, PNA) on fire-climate interactions is evident in contemporary fire data sets and in pre-Euroamerican tree-ring-based fire records. We investigated how interannual variability in two fire weather indices, the Haines index (HI) and the Energy Release Component (ERC), in the Mediterranean region of southern Oregon and northern California is related to atmospheric circulation and fire extent. Years with high and low fire weather index values corresponded to years with a high and low annual area burned, respectively. HI combines atmospheric moisture with atmospheric instability and variation in HI was more strongly associated with interannual variation in wildfire extent than ERC, which is based on moisture alone. The association between fire extent and HI was also higher for fires in southern Oregon than in northern California. In terms of synoptic-scale circulation patterns, years of high fire risk (i.e., increased potential for erratic fire behavior, represented by HI and ERC) were associated with positive winter PNA and PDO conditions, characterized by enhanced regional mid-tropospheric ridging and low atmospheric moisture. The time lag we found between fire risk potential and prior winter circulation patterns could contribute to the development of long-lead fire-climate forecasting.

  18. Large Scale Predictions of Potential Post-fire Erosion

    Science.gov (United States)

    Miller, M. E.; MacDonald, L. H.

    2005-12-01

    High-severity wildfires are of increasing concern because of their potential for initiating flash floods and surface erosion, degrading water quality, and reducing reservoir capacity. In many areas fire suppression has increased fuel accumulations and hence the potential for high-severity wildfires. Land management agencies are undertaking programs to reduce fuel loadings and the associated risk of high-severity wildfires, but the areas needing treatment greatly exceed the available funding. It is therefore necessary to determine which areas should have a higher priority for such treatments. Similarly, when wildfires do occur there is an immediate need to determine which areas should have the highest priority for post-fire rehabilitation treatments. One criterion for allocating treatments is the potential risk of post-fire erosion, but to be effective this assessment needs to be carried out at a broad scale. This paper presents a procedure and initial results for predicting spatially-explicit, post-fire erosion risks at the hillslope scale for forest and shrub lands across the western U.S. Our approach utilizes existing physical models and datasets in a GIS framework. The model for predicting erosion is GeoWEPP, the Geographical interface for the Water Erosion Prediction Project (WEPP). The primary inputs for GeoWEPP include climate, topography, soils, and land cover/land use. Daily climate inputs were generated with Cligen, which is a stochastic weather generator distributed with WEPP. A 30-m digital elevation model, STATSGO-derived soils data, and vegetation cover were obtained from the U.S. Forest Service's LANDFIRE project. Since recent research has shown that percent ground cover is a dominant control on post-fire erosion rates, we generated a spatially-explicit map of post-fire ground cover by first using historic weather data to determine the 1000-hr fuel moisture values when fuel conditions were at 98-100% ERC (Energy Released Component). These fuel

  19. Synoptic-scale and mesoscale environments conducive to forest fires during the October 2003 extreme fire event in Southern California

    Science.gov (United States)

    Chenjie Huang; Y.L. Lin; M.L. Kaplan; Joseph J.J. Charney

    2009-01-01

    This study has employed both observational data and numerical simulation results to diagnose the synoptic-scale and mesoscale environments conducive to forest fires during the October 2003 extreme fire event in southern California. A three-stage process is proposed to illustrate the coupling of the synoptic-scale forcing that is evident from the observations,...

  20. Adding Fuel to the Fire: The Impacts of Non-Native Grass Invasion on Fire Management at a Regional Scale

    Science.gov (United States)

    Setterfield, Samantha A.; Rossiter-Rachor, Natalie A.; Douglas, Michael M.; Wainger, Lisa; Petty, Aaron M.; Barrow, Piers; Shepherd, Ian J.; Ferdinands, Keith B.

    2013-01-01

    Background Widespread invasion by non-native plants has resulted in substantial change in fire-fuel characteristics and fire-behaviour in many of the world's ecosystems, with a subsequent increase in the risk of fire damage to human life, property and the environment. Models used by fire management agencies to assess fire risk are dependent on accurate assessments of fuel characteristics but there is little evidence that they have been modified to reflect landscape-scale invasions. There is also a paucity of information documenting other changes in fire management activities that have occurred to mitigate changed fire regimes. This represents an important limitation in information for both fire and weed risk management. Methodology/Principal Findings We undertook an aerial survey to estimate changes to landscape fuel loads in northern Australia resulting from invasion by Andropogon gayanus (gamba grass). Fuel load within the most densely invaded area had increased from 6 to 10 t ha−1 in the past two decades. Assessment of the effect of calculating the Grassland Fire Danger Index (GFDI) for the 2008 and 2009 fire seasons demonstrated that an increase from 6 to 10 t ha−1 resulted in an increase from five to 38 days with fire risk in the ‘severe’ category in 2008 and from 11 to 67 days in 2009. The season of severe fire weather increased by six weeks. Our assessment of the effect of increased fuel load on fire management practices showed that fire management costs in the region have increased markedly (∼9 times) in the past decade due primarily to A. gayanus invasion. Conclusions/Significance This study demonstrated the high economic cost of mitigating fire impacts of an invasive grass. This study demonstrates the need to quantify direct and indirect invasion costs to assess the risk of further invasion and to appropriately fund fire and weed management strategies. PMID:23690917

  1. Identification of aeroelastic forces and static drag coefficients of a twin cable bridge stay from full-scale ambient vibration measurements

    DEFF Research Database (Denmark)

    Acampora, Antonio; Georgakis, Christos T.; Macdonald, J.H.G.

    2014-01-01

    rather than reduced velocity, indicating that Reynolds number governs the aeroelastic effects in these conditions. There is a significant drop in the aerodynamic damping in the critical Reynolds number range, which is believed to be related to the large amplitude cable vibrations observed on some bridges...... presents results from full-scale measurements on the special arrangement of twin cables adopted for the Øresund Bridge. The monitoring system records wind and weather conditions, as well as accelerations of certain cables and a few locations on the deck and tower. Using the Eigenvalue Realization Algorithm...... (ERA), the damping and stiffness matrices are identified for different vibration modes of the cables, with sufficient accuracy to identify changes in the total effective damping and stiffness matrices due to the aeroelastic forces acting on the cables. The damping matrices identified from the full...

  2. submitter Design and Manufacturing of a 45 kA at 10 T REBCO-CORC Cable-in-Conduit Conductor for Large-Scale Magnets

    CERN Document Server

    Mulder, Tim; Mentink, Matthias; Silva, Helder; van der Laan, Danko; Dhalle, Marc; ten Kate, Herman

    2016-01-01

    The European Organization for Nuclear Research (CERN) is developing high-current ReBCO-CORC strand-based cables for use in future large-scale detector magnets. A six-around-one, forced flow gas-cooled ReBCO-CORC cable-in-conduit conductor (CICC) is envisioned for application in magnets operating in the 20-40 K temperature range. A CICC, rated for 45 kA at 4.2 K and 10 T, is designed and in production. The CICC comprises a cable of six CORC strands helically wound around a tube. The cable has an expected current density of 105 $A/mm^2$ at 10 T/4.2 K, which corresponds to an overall current density of 53 $A/mm^2$. A cable current density of 110 $A/mm^2$ can be reached when increasing the temperature to 20 K and operating in a magnetic field of 5 T.

  3. Post-fire bedload sediment delivery across spatial scales in the interior western United States

    Science.gov (United States)

    Joseph W. Wagenbrenner; Peter R. Robichaud

    2014-01-01

    Post-fire sediment yields can be up to three orders of magnitude greater than sediment yields in unburned forests. Much of the research on post-fire erosion rates has been at small scales (100m2 or less), and post-fire sediment delivery rates across spatial scales have not been quantified in detail. We developed relationships for post-fire bedload sediment delivery...

  4. Identification of aeroelastic forces on twin bridge cables from full-scale measurements in skew winds

    DEFF Research Database (Denmark)

    Acampora, Antonio; Macdonald, J.H.G.; Georgakis, Christos T.

    2012-01-01

    of this paper is to identify the aeroelastic forces for in-plane and out-of-plane vibrations of bridge cables in dry conditions as in [2], but now for skewed winds. To achieve this, an output-only system identification employing the Eigenvalue Realisation Algorithm (ERA) [3] has been applied to selected...

  5. Understanding of bridge cable vibrations and the associate flow-field through the full-scale monitoring of vibrations and Wind

    DEFF Research Database (Denmark)

    Acampora, Antonio

    bridges continuously becoming longer and lighter have resulted in a high number of observations of cable vibrations. A theoretical background for the tool used in this work is presented in terms of cables vibrations mechanisms, aerodynamic damping and system identification techniques. A detailed......-scale monitoring events. Special thanks to Rune Brincker to grant permission to use the material of his newly published book about system identification to form the chapter of this thesis. A special thanks also to Anela Bajeric for granting the permission to use her material about system identification review...... vibrations. The research starts from data collection of cables vibrations of the Øresund Bridge. A dedicated monitoring system was installed to record full-scale data together with wind field measurements and meteorological data, during cables vibrations. Results from the monitoring system are reported...

  6. Driving factors of small-scale variability in a savanna plant population after a fire

    Science.gov (United States)

    Dodonov, Pavel; Xavier, Rafael de Oliveira; Tiberio, Fernanda Cristina dos Santos; Lucena, Isabela Codolo de; Zanelli, Carolina Brandão; Silva Matos, Dalva Maria da

    2014-04-01

    The severity of fire impacts on fire-prone vegetation is often spatially heterogeneous, and may lead to small-scale patchiness in the structure of plant populations by affecting mortality, topkill, and reproduction. This patchiness, however, is not usually taken into account in fire ecology studies. We show that a dry-season fire may result in small-scale patchiness in the population structure of the common shrub Miconia albicans, mostly by differential topkill and resprouting. We related fire severity to population structure parameters of the study species and assessed the effects of fire on its soil seed bank. Basal area of non-woody live stems and of dead stems increased with fire severity, whereas that of woody live stems decreased, indicating topkill and resprouting. However, there was no relationship between fire severity and the total number of live or dead plants, showing that mortality in the fire was low. We found very few seedlings, indicating that resprouting, not germination from the soil seed bank, is the main recovery strategy of this species. The fire also affected the soil seed bank, as there were fewer seedlings emerging from soil collected in burned patches. Although this study was performed with a single species, it is likely that other species, especially those with basal resprouting, will show similar patterns of post-fire patchiness in population structure. This patchiness, in turn, may affect the spatial distribution of future fires, and should be taken into account in studies of fire ecology.

  7. Broad-Scale Environmental Conditions Responsible for Post-Fire Vegetation Dynamics

    Directory of Open Access Journals (Sweden)

    Stuart E. Marsh

    2010-11-01

    Full Text Available Ecosystem response to disturbance is influenced by environmental conditions at a number of scales. Changes in climate have altered fire regimes across the western United States, and have also likely altered spatio-temporal patterns of post-fire vegetation regeneration. Fire occurrence data and a vegetation index (NDVI derived from the NOAA Advanced Very High Resolution Radiometer (AVHRR were used to monitor post-fire vegetation from 1989 to 2007. We first investigated differences in post-fire rates of vegetation regeneration between ecoregions. We then related precipitation, temperature, and elevation records at four temporal scales to rates of post-fire vegetation regeneration to ascertain the influence of climate on post-fire vegetation dynamics. We found that broad-scale climate factors are an important influence on post-fire vegetation regeneration. Most notably, higher rates of post-fire regeneration occurred with warmer minimum temperatures. Increases in precipitation also resulted in higher rates of post-fire vegetation growth. While explanatory power was slight, multiple statistical approaches provided evidence for real ecological drivers of post-fire regeneration that should be investigated further at finer scales. The sensitivity of post-disturbance vegetation dynamics to climatic drivers has important ramifications for the management of ecosystems under changing climatic conditions. Shifts in temperature and precipitation regimes are likely to result in changes in post-disturbance dynamics, which could represent important feedbacks into the global climate system.

  8. Research and management issues in large-scale fire modeling

    Science.gov (United States)

    David L. Peterson; Daniel L. Schmoldt

    2000-01-01

    In 1996, a team of North American fire scientists and resource managers convened to assess the effects of fire disturbance on ecosystems and to develop scientific recommendations for future fire research and management activities. These recommendations - elicited with the Analytic Hierarchy Process - include numerically ranked scientific and managerial questions and...

  9. Modeling regional-scale wildland fire emissions with the wildland fire emissions information system

    Science.gov (United States)

    Nancy H.F. French; Donald McKenzie; Tyler Erickson; Benjamin Koziol; Michael Billmire; K. Endsley; Naomi K.Y. Scheinerman; Liza Jenkins; Mary E. Miller; Roger Ottmar; Susan Prichard

    2014-01-01

    As carbon modeling tools become more comprehensive, spatial data are needed to improve quantitative maps of carbon emissions from fire. The Wildland Fire Emissions Information System (WFEIS) provides mapped estimates of carbon emissions from historical forest fires in the United States through a web browser. WFEIS improves access to data and provides a consistent...

  10. New turbulent resistance parameterization for soil evaporation based on a pore-scale model: Impact on surface fluxes in CABLE

    Science.gov (United States)

    Decker, Mark; Or, Dani; Pitman, Andy; Ukkola, Anna

    2017-03-01

    The Community Atmosphere Biosphere Land Exchange (CABLE) land surface model overestimates evapotranspiration (E) at numerous flux tower sites during boreal spring. The overestimation of E is not eliminated when the nonlinear dependence of soil evaporation on soil moisture or a simple litter layer is introduced into the model. New resistance terms, previously developed from a pore-scale model of soil evaporation, are incorporated into the treatment of under canopy water vapor transfer in CABLE. The new resistance terms reduce the large positive bias in spring time E at multiple flux tower sites and also improve the simulation of daily sensible heat flux. The reduction in the spring E bias allows the soil to retain water into the summer, improving the seasonality of E. The simulation of daily E is largely insensitive to the details of the implementation of the pore model resistance scheme. The more physically based treatment of soil evaporation presented here eliminates the need for empirical functions that reduce evaporation as a function of soil moisture that are included in many land surface models.

  11. Scaled Experimental Study on Maximum Smoke Temperature along Corridors Subject to Room Fires

    Directory of Open Access Journals (Sweden)

    Zheli Xing

    2015-08-01

    Full Text Available In room–corridor building geometry, the corridor smoke temperature is of great importance to fire protection engineering as indoor fires occur. Theoretical analysis and a set of reduced-scale model experiments were performed, and a virtual fire model was proposed, to investigate the correlations between the maximum smoke temperature in corridors and the smoke temperature in rooms. The results show that the dimensionless virtual fire heat release rate (HRR is characterized by quadratic-polynomial of the dimensionless smoke temperature in fire rooms. The dimensionless distance from a virtual fire source to the corridor ceiling varies linearly with the dimensionless smoke temperature in a room. Results of multiple regression indicate that, at the impingement area of virtual fire, the dimensionless maximum smoke temperature in corridors is only related to the dimensionless virtual fire HRR; in the non-impingement area of a virtual fire, the dimensionless maximum smoke temperature in corridors is a function of the dimensionless virtual fire HRR and dimensionless longitude distance. The viscosity and conduction exhibit an insignificant impact on the maximum temperature in the corridor. Through replacing the parameters of virtual fire with the dimensionless smoke temperature in fire rooms, the correlations between dimensionless maximum temperature in corridors and the dimensionless smoke temperature in fire rooms were proposed.

  12. Superconductor cable

    Science.gov (United States)

    Allais, Arnaud; Schmidt, Frank; Marzahn, Erik

    2010-05-04

    A superconductor cable is described, having a superconductive flexible cable core (1) , which is laid in a cryostat (2, 3, 4), in which the cable core (1) runs in the cryostat (2, 3, 4) in the form of a wave or helix at room temperature.

  13. Co-firing of Coal with Biomass and Waste in Full-scale Suspension-fired Boilers

    DEFF Research Database (Denmark)

    Dam-Johansen, Kim; Jappe Frandsen, Flemming; Jensen, Peter Arendt

    2013-01-01

    The energy policy in Denmark has for many years focused on lowering the net CO2 emission from heat and power production by replacing fossil fuels by renewable resources. This has been done by developing dedicated grate-fired boilers for biomass and waste fuels but also by developing coal...... and boiler manufacturers to optimize design and operation and minimize cost and environmental impact using alternative fuels in suspension fired boilers. Our contribution has been made via a combination of full-scale measuring campaigns, pilot-scale studies, lab-scale measurements and modeling tools......-based suspension-fired boilers to accept still higher fractions of biomass or waste material as fuels. This last development has been challenging of many reasons, including pre-treatment of fuels, and solving potential emission and operational problems during the simultaneous development of supercritical steam...

  14. Regional scales of fire danger rating in the forest: improved technique

    Directory of Open Access Journals (Sweden)

    A. V. Volokitina

    2017-04-01

    Full Text Available Wildland fires distribute unevenly in time and over area under the influence of weather and other factors. It is unfeasible to air patrol the whole forest area daily during a fire season as well as to keep all fire suppression forces constantly alert. Daily work and preparedness of forest fire protection services is regulated by the level of fire danger according to weather conditions (Nesterov’s index. PV-1 index, fire hazard class (Melekhov’s scale, regional scales (earlier called local scales. Unfortunately, there is still no unified comparable technique of making regional scales. As a result, it is difficult to maneuver forest fire protection resources, since the techniques currently used are not approved and not tested for their performance. They give fire danger rating incomparable even for neighboring regions. The paper analyzes the state-of-the-art in Russia and abroad. It is stated the irony is that with factors of fire danger measured quantitatively, the fire danger itself as a function has no quantitative expression. Thus, selection of an absolute criteria is of high importance for improvement of daily fire danger rating. On the example of the Chunsky forest ranger station (Krasnoyarsk Krai, an improved technique is suggested of making comparable local scales of forest fire danger rating based on an absolute criterion of fire danger rating – a probable density of active fires per million ha. A method and an algorithm are described of automatized local scales of fire danger that should facilitate effective creation of similar scales for any forest ranger station or aviation regional office using a database on forest fires and weather conditions. The information system of distant monitoring by Federal Forestry Agency of Russia is analyzed for its application in making local scales. To supplement the existing weather station net it is suggested that automatic compact weather stations or, if the latter is not possible, simple

  15. Fractional cable equation models for anomalous electrodiffusion in nerve cells: infinite domain solutions.

    Science.gov (United States)

    Langlands, T A M; Henry, B I; Wearne, S L

    2009-12-01

    We introduce fractional Nernst-Planck equations and derive fractional cable equations as macroscopic models for electrodiffusion of ions in nerve cells when molecular diffusion is anomalous subdiffusion due to binding, crowding or trapping. The anomalous subdiffusion is modelled by replacing diffusion constants with time dependent operators parameterized by fractional order exponents. Solutions are obtained as functions of the scaling parameters for infinite cables and semi-infinite cables with instantaneous current injections. Voltage attenuation along dendrites in response to alpha function synaptic inputs is computed. Action potential firing rates are also derived based on simple integrate and fire versions of the models. Our results show that electrotonic properties and firing rates of nerve cells are altered by anomalous subdiffusion in these models. We have suggested electrophysiological experiments to calibrate and validate the models.

  16. The Design of a Fire Source in Scale-Model Experiments with Smoke Ventilation

    DEFF Research Database (Denmark)

    Nielsen, Peter Vilhelm; Brohus, Henrik; la Cour-Harbo, H.

    2004-01-01

    The paper describes the design of a fire and a smoke source for scale-model experiments with smoke ventilation. It is only possible to work with scale-model experiments where the Reynolds number is reduced compared to full scale, and it is demonstrated that special attention to the fire source...... (heat and smoke source) may improve the possibility of obtaining Reynolds number independent solutions with a fully developed flow. The paper shows scale-model experiments for the Ofenegg tunnel case. Design of a fire source for experiments with smoke ventilation in a large room and smoke movement...

  17. High prevalence of insulation failure with externalized cables in St. Jude Medical Riata family ICD leads: fluoroscopic grading scale and correlation to extracted leads.

    Science.gov (United States)

    Parvathaneni, Sunthosh V; Ellis, Christopher R; Rottman, Jeffrey N

    2012-08-01

    Inside-out abrasion with externalization of sensing ring or high-voltage cables in St Jude Medical Riata implantable cardioverter-defibrillator leads has been reported. The prevalence of extruded cables, rate of electrical abnormalities, and predictors of failure in Riata leads are unknown. To estimate the incidence of lead failure in the St Jude Medical Riata implantable cardioverter-defibrillator leads and to propose a standard for the fluoroscopic assessment of insulation breakdown. Patients undergoing cine-fluoroscopy on Riata implantable cardioverter-defibrillator leads at our institution before January 25, 2012, were included (n = 87). Leads were graded as types 0-3 (0 = normal, 1 = abnormal conductor spacing, 2 ≤1 cm cable extrusion, 3 = >1 cm length extrusion). Comparison to extracted leads (n = 15) was documented. Device interrogation data were used for electrical analysis. The mean time from implant was 5.9 ± 3.45 years. Structural lead failure with externalized cables was seen in 33.3% (29 of 87) of the patients. Thirty-one percent (9 of 29) of the leads with exposed cables showed electrical failure, and 29.7% (19 of 64) of the leads with normal electrical data contained externalized cables. Time from implant ≥5 years predicted structural lead failure (P leads demonstrated a sensitivity and specificity of 86% and 100%, respectively. Cine-fluoroscopy using a simple scale correlated with the structural integrity of extracted Riata leads. A high percentage of leads with extrusion showed electrical failure. Leads ≥5 years from implant showed a high rate of externalized cables. A large independent multicenter study to determine the prevalence and clinical sequelae of Riata lead failures is warranted. Copyright © 2012 Heart Rhythm Society. All rights reserved.

  18. Fuel consumption and fire emissions estimates using Fire Radiative Power, burned area and statistical modelling on the fire event scale

    Science.gov (United States)

    Ruecker, Gernot; Leimbach, David; Guenther, Felix; Barradas, Carol; Hoffmann, Anja

    2016-04-01

    Fire Radiative Power (FRP) retrieved by infrared sensors, such as flown on several polar orbiting and geostationary satellites, has been shown to be proportional to fuel consumption rates in vegetation fires, and hence the total radiative energy released by a fire (Fire Radiative Energy, FRE) is proportional to the total amount of biomass burned. However, due to the sparse temporal coverage of polar orbiting and the coarse spatial resolution of geostationary sensors, it is difficult to estimate fuel consumption for single fire events. Here we explore an approach for estimating FRE through temporal integration of MODIS FRP retrievals over MODIS-derived burned areas. Temporal integration is aided by statistical modelling to estimate missing observations using a generalized additive model (GAM) and taking advantage of additional information such as land cover and a global dataset of the Canadian Fire Weather Index (FWI), as well as diurnal and annual FRP fluctuation patterns. Based on results from study areas located in savannah regions of Southern and Eastern Africa and Brazil, we compare this method to estimates based on simple temporal integration of FRP retrievals over the fire lifetime, and estimate the potential variability of FRP integration results across a range of fire sizes. We compare FRE-based fuel consumption against a database of field experiments in similar landscapes. Results show that for larger fires, this method yields realistic estimates and is more robust when only a small number of observations is available than the simple temporal integration. Finally, we offer an outlook on the integration of data from other satellites, specifically FireBird, S-NPP VIIRS and Sentinel-3, as well as on using higher resolution burned area data sets derived from Landsat and similar sensors.

  19. Fluid dynamics structures in a fire environment observed in laboratory-scale experiments

    Science.gov (United States)

    J. Lozano; W. Tachajapong; D.R. Weise; S. Mahalingam; M. Princevac

    2010-01-01

    Particle Image Velocimetry (PIV) measurements were performed in laboratory-scale experimental fires spreading across horizontal fuel beds composed of aspen (Populus tremuloides Michx) excelsior. The continuous flame, intermittent flame, and thermal plume regions of a fire were investigated. Utilizing a PIV system, instantaneous velocity fields for...

  20. Cable compliance

    Science.gov (United States)

    Kerley, J.; Eklund, W.; Burkhardt, R.; Rossoni, P.

    1992-06-01

    The object of the investigation was to solve mechanical problems using cable-in-bending and cable-in-torsion. These problems included robotic contacts, targets, and controls using cable compliance. Studies continued in the use of cable compliance for the handicapped and the elderly. These included work stations, walkers, prosthetic knee joints, elbow joints, and wrist joints. More than half of these objects were met, and models were made and studies completed on most of the others. It was concluded that the many different and versatile solutions obtained only opened the door to many future challenges.

  1. Termites Are Resistant to the Effects of Fire at Multiple Spatial Scales.

    Directory of Open Access Journals (Sweden)

    Sarah C Avitabile

    Full Text Available Termites play an important ecological role in many ecosystems, particularly in nutrient-poor arid and semi-arid environments. We examined the distribution and occurrence of termites in the fire-prone, semi-arid mallee region of south-eastern Australia. In addition to periodic large wildfires, land managers use fire as a tool to achieve both asset protection and ecological outcomes in this region. Twelve taxa of termites were detected by using systematic searches and grids of cellulose baits at 560 sites, clustered in 28 landscapes selected to represent different fire mosaic patterns. There was no evidence of a significant relationship between the occurrence of termite species and time-since-fire at the site scale. Rather, the occurrence of species was related to habitat features such as the density of mallee trees and large logs (>10 cm diameter. Species richness was greater in chenopod mallee vegetation on heavier soils in swales, rather than Triodia mallee vegetation of the sandy dune slopes. At the landscape scale, there was little evidence that the frequency of occurrence of termite species was related to fire, and no evidence that habitat heterogeneity generated by fire influenced termite species richness. The most influential factor at the landscape scale was the environmental gradient represented by average annual rainfall. Although termites may be associated with flammable habitat components (e.g. dead wood, they appear to be buffered from the effects of fire by behavioural traits, including nesting underground, and the continued availability of dead wood after fire. There is no evidence to support the hypothesis that a fine-scale, diverse mosaic of post-fire age-classes will enhance the diversity of termites. Rather, termites appear to be resistant to the effects of fire at multiple spatial scales.

  2. Termites Are Resistant to the Effects of Fire at Multiple Spatial Scales.

    Science.gov (United States)

    Avitabile, Sarah C; Nimmo, Dale G; Bennett, Andrew F; Clarke, Michael F

    2015-01-01

    Termites play an important ecological role in many ecosystems, particularly in nutrient-poor arid and semi-arid environments. We examined the distribution and occurrence of termites in the fire-prone, semi-arid mallee region of south-eastern Australia. In addition to periodic large wildfires, land managers use fire as a tool to achieve both asset protection and ecological outcomes in this region. Twelve taxa of termites were detected by using systematic searches and grids of cellulose baits at 560 sites, clustered in 28 landscapes selected to represent different fire mosaic patterns. There was no evidence of a significant relationship between the occurrence of termite species and time-since-fire at the site scale. Rather, the occurrence of species was related to habitat features such as the density of mallee trees and large logs (>10 cm diameter). Species richness was greater in chenopod mallee vegetation on heavier soils in swales, rather than Triodia mallee vegetation of the sandy dune slopes. At the landscape scale, there was little evidence that the frequency of occurrence of termite species was related to fire, and no evidence that habitat heterogeneity generated by fire influenced termite species richness. The most influential factor at the landscape scale was the environmental gradient represented by average annual rainfall. Although termites may be associated with flammable habitat components (e.g. dead wood), they appear to be buffered from the effects of fire by behavioural traits, including nesting underground, and the continued availability of dead wood after fire. There is no evidence to support the hypothesis that a fine-scale, diverse mosaic of post-fire age-classes will enhance the diversity of termites. Rather, termites appear to be resistant to the effects of fire at multiple spatial scales.

  3. Numerical modeling of water spray suppression of conveyor belt fires in a large-scale tunnel.

    Science.gov (United States)

    Yuan, Liming; Smith, Alex C

    2015-05-01

    Conveyor belt fires in an underground mine pose a serious life threat to miners. Water sprinkler systems are usually used to extinguish underground conveyor belt fires, but because of the complex interaction between conveyor belt fires and mine ventilation airflow, more effective engineering designs are needed for the installation of water sprinkler systems. A computational fluid dynamics (CFD) model was developed to simulate the interaction between the ventilation airflow, the belt flame spread, and the water spray system in a mine entry. The CFD model was calibrated using test results from a large-scale conveyor belt fire suppression experiment. Simulations were conducted using the calibrated CFD model to investigate the effects of sprinkler location, water flow rate, and sprinkler activation temperature on the suppression of conveyor belt fires. The sprinkler location and the activation temperature were found to have a major effect on the suppression of the belt fire, while the water flow rate had a minor effect.

  4. Fire activity as a function of fire-weather seasonal severity and antecedent climate across spatial scales in southern Europe and Pacific western USA

    Science.gov (United States)

    Urbieta, Itziar R.; Zavala, Gonzalo; Bedia, Joaquín; Gutiérrez, José M.; San Miguel-Ayanz, Jesús; Camia, Andrea; Keeley, Jon E.; Moreno, José M.

    2015-11-01

    Climate has a strong influence on fire activity, varying across time and space. We analyzed the relationships between fire-weather conditions during the main fire season and antecedent water-balance conditions and fires in two Mediterranean-type regions with contrasted management histories: five southern countries of the European Union (EUMED)(all fires); the Pacific western coast of the USA (California and Oregon, PWUSA)(national forest fires). Total number of fires (≥1 ha), number of large fires (≥100 ha) and area burned were related to mean seasonal fire weather index (FWI), number of days over the 90th percentile of the FWI, and to the standardized precipitation-evapotranspiration index (SPEI) from the preceding 3 (spring) or 8 (autumn through spring) months. Calculations were made at three spatial aggregations in each area, and models related first-difference (year-to-year change) of fires and FWI/climate variables to minimize autocorrelation. An increase in mean seasonal FWI resulted in increases in the three fire variables across spatial scales in both regions. SPEI contributed little to explain fires, with few exceptions. Negative water-balance (dry) conditions from autumn through spring (SPEI8) were generally more important than positive conditions (moist) in spring (SPEI3), both of which contributed positively to fires. The R2 of the models generally improved with increasing area of aggregation. For total number of fires and area burned, the R2 of the models tended to decrease with increasing mean seasonal FWI. Thus, fires were more susceptible to change with climate variability in areas with less amenable conditions for fires (lower FWI) than in areas with higher mean FWI values. The relationships were similar in both regions, albeit weaker in PWUSA, probably due to the wider latitudinal gradient covered in PWUSA than in EUMED. The large variance explained by some of the models indicates that large-scale seasonal forecast could help anticipating fire

  5. Does fire influence the landscape-scale distribution of an invasive mesopredator?

    Directory of Open Access Journals (Sweden)

    Catherine J Payne

    Full Text Available Predation and fire shape the structure and function of ecosystems globally. However, studies exploring interactions between these two processes are rare, especially at large spatial scales. This knowledge gap is significant not only for ecological theory, but also in an applied context, because it limits the ability of landscape managers to predict the outcomes of manipulating fire and predators. We examined the influence of fire on the occurrence of an introduced and widespread mesopredator, the red fox (Vulpes vulpes, in semi-arid Australia. We used two extensive and complimentary datasets collected at two spatial scales. At the landscape-scale, we surveyed red foxes using sand-plots within 28 study landscapes - which incorporated variation in the diversity and proportional extent of fire-age classes - located across a 104 000 km2 study area. At the site-scale, we surveyed red foxes using camera traps at 108 sites stratified along a century-long post-fire chronosequence (0-105 years within a 6630 km2 study area. Red foxes were widespread both at the landscape and site-scale. Fire did not influence fox distribution at either spatial scale, nor did other environmental variables that we measured. Our results show that red foxes exploit a broad range of environmental conditions within semi-arid Australia. The presence of red foxes throughout much of the landscape is likely to have significant implications for native fauna, particularly in recently burnt habitats where reduced cover may increase prey species' predation risk.

  6. Modelling the spreading of large-scale wildland fires

    CERN Document Server

    Drissi, Mohamed

    2014-01-01

    The objective of the present study is twofold. First, the last developments and validation results of a hybrid model designed to simulate fire patterns in heterogeneous landscapes are presented. The model combines the features of a stochastic small-world network model with those of a deterministic semi-physical model of the interaction between burning and non-burning cells that strongly depends on local conditions of wind, topography, and vegetation. Radiation and convection from the flaming zone, and radiative heat loss to the ambient are considered in the preheating process of unburned cells. Second, the model is applied to an Australian grassland fire experiment as well as to a real fire that took place in Corsica in 2009. Predictions compare favorably to experiments in terms of rate of spread, area and shape of the burn. Finally, the sensitivity of the model outcomes (here the rate of spread) to six input parameters is studied using a two-level full factorial design.

  7. Modeling Fire Susceptibility to Delineate Wildland-Urban Interface for Municipal-Scale Fire Risk Management

    Science.gov (United States)

    Whitman, Ellen; Rapaport, Eric; Sherren, Kate

    2013-12-01

    The wildland-urban interface (WUI) is the region where development meets and intermingles with wildlands. The WUI has an elevated fire risk due to the proximity of development and residents to wildlands with natural wildfire regimes. Existing methods of delineating WUI are typically applied over a large region, use proxies for risk, and do not consider site-specific fire hazard drivers. While these models are appropriate for federal and provincial risk management, municipal managers require models intended for smaller regions. The model developed here uses the Burn-P3 fire behavior model to model WUI from local fire susceptibility (FS) in two study communities. Forest fuel code (FFC) maps for the study communities were modified using remote sensing data to produce detailed forest edges, including ladder fuels, update data currency, and add buildings and roads. The modified FFC maps used in Burn-P3 produced bimodal FS distributions for each community. The WUI in these communities was delineated as areas within community bounds where FS was greater than or equal to -1 SD from the mean FS value (), which fell in the trough of the bimodal distribution. The WUI so delineated conformed to the definition of WUI. This model extends WUI modeling for broader risk management initiatives for municipal management of risk, as it (a) considers site-specific drivers of fire behavior; (b) models risk, represented by WUI, specific to a community; and, (c) does not use proxies for risk.

  8. Length of a Hanging Cable

    Directory of Open Access Journals (Sweden)

    Eric Costello

    2011-01-01

    Full Text Available The shape of a cable hanging under its own weight and uniform horizontal tension between two power poles is a catenary. The catenary is a curve which has an equation defined by a hyperbolic cosine function and a scaling factor. The scaling factor for power cables hanging under their own weight is equal to the horizontal tension on the cable divided by the weight of the cable. Both of these values are unknown for this problem. Newton's method was used to approximate the scaling factor and the arc length function to determine the length of the cable. A script was written using the Python programming language in order to quickly perform several iterations of Newton's method to get a good approximation for the scaling factor.

  9. Contribution of regional-scale fire events to ozone and PM2.5 ...

    Science.gov (United States)

    Two specific fires from 2011 are tracked for local to regional scale contribution to ozone (O3) and fine particulate matter (PM2.5) using a freely available regulatory modeling system that includes the BlueSky wildland fire emissions tool, Spare Matrix Operator Kernel Emissions (SMOKE) model, Weather and Research Forecasting (WRF) meteorological model, and Community Multiscale Air Quality (CMAQ) photochemical grid model. The modeling system was applied to track the contribution from a wildfire (Wallow) and prescribed fire (Flint Hills) using both source sensitivity and source apportionment approaches. The model estimated fire contribution to primary and secondary pollutants are comparable using source sensitivity (brute-force zero out) and source apportionment (Integrated Source Apportionment Method) approaches. Model estimated O3 enhancement relative to CO is similar to values reported in literature indicating the modeling system captures the range of O3 inhibition possible near fires and O3 production both near the fire and downwind. O3 and peroxyacetyl nitrate (PAN) are formed in the fire plume and transported downwind along with highly reactive VOC species such as formaldehyde and acetaldehyde that are both emitted by the fire and rapidly produced in the fire plume by VOC oxidation reactions. PAN and aldehydes contribute to continued downwind O3 production. The transport and thermal decomposition of PAN to nitrogen oxides (NOX) enables O3 production in areas

  10. Modeling the spreading of large-scale wildland fires

    Science.gov (United States)

    Mohamed Drissi

    2015-01-01

    The objective of the present study is twofold. First, the last developments and validation results of a hybrid model designed to simulate fire patterns in heterogeneous landscapes are presented. The model combines the features of a stochastic small-world network model with those of a deterministic semi-physical model of the interaction between burning and non-burning...

  11. Fire and plant diversity at the global scale

    NARCIS (Netherlands)

    Pausas, Juli G.; Carvalho Ribeiro, Eloi

    2017-01-01

    Aim: Understanding the drivers of global diversity has challenged ecologists for decades. Drivers related to the environment, productivity and heterogeneity are considered primary factors, whereas disturbance has received less attention. Given that fire is a global factor that has been affecting

  12. Modeling of the Critical-Current Behavior of Nb3Sn Subsized Cables Under Transverse Load Using 2D Finite Element Analysis and a Strain Scaling Law

    CERN Document Server

    Wang, T; Takayasu, M; Bordini, B

    2014-01-01

    The mechanisms causing the critical-current degradation of ITER-type Nb3Sn Cable-in-Conduit-Conductors have been studied in the past decade. One of the origins of the degradation of the performance is the Lorentz load during magnet operations. The strands within the cable subjected to the transverse loads locally experience larger strains than the ones caused by tensile loads. Results obtained with experiments on full size cables are limited due to their cost and difficulty so, to predict the degradations of a Nb3Sn CICC under transverse loads, empirical laws should be established. Strain scaling laws are available but have never been used to determine the behavior of strands under transverse load. We propose a new method, by which the critical-current behavior of a subsized cable under transverse loads is derived from the critical-current behavior under uni-axial strains. This method is based on the strain state of the Nb3Sn filaments obtained by finite element analysis (FEA). The FEA strain results are used...

  13. AC Cable: Yokohama Project

    Science.gov (United States)

    Masuda, Takato

    High Temperature Superconducting (HTS) cables can transmit large amounts of electricity in a compact size with minimal losses. Therefore, they are expected to save the construction cost of underground lines in urban areas and decrease transmission losses. Several HTS cables have recently been demonstrated in networks around the world, and full-scale commercialization is expected in the near future. In Japan, the development of compact HTS cables suitable for urban deployment has been underway since the early 1990s. In 2007, a national project was started to verify their operational performance and long-term reliability in the grid. An HTS cable 240 m long was installed at the Asahi substation of the Tokyo Electric Power Company (TEPCO) in Yokohama; then a joint, terminations and cooling system was constructed in 2011. After successful performance tests, the cable was connected to the grid for the first time in Japan, and started to deliver electricity to 70,000 households in October 2012. This trouble-free in-grid service continued for over a year. We can conclude that the HTS cable system performs well and has the stability required for long-term in-grid operations.

  14. Optical Measurement of Cable and String Vibration

    Directory of Open Access Journals (Sweden)

    Y. Achkire

    1998-01-01

    Full Text Available This paper describes a non contacting measurement technique for the transverse vibration of small cables and strings using an analog position sensing detector. On the one hand, the sensor is used to monitor the cable vibrations of a small scale mock-up of a cable structure in order to validate the nonlinear cable dynamics model. On the other hand, the optical sensor is used to evaluate the performance of an active tendon control algorithm with guaranteed stability properties. It is demonstrated experimentally, that a force feedback control law based on a collocated force sensor measuring the tension in the cable is feasible and provides active damping in the cable.

  15. Large-Scale Spacecraft Fire Safety Experiments in ISS Resupply Vehicles

    Science.gov (United States)

    Ruff, Gary A.; Urban, David

    2013-01-01

    Our understanding of the fire safety risk in manned spacecraft has been limited by the small scale of the testing we have been able to conduct in low-gravity. Fire growth and spread cannot be expected to scale linearly with sample size so we cannot make accurate predictions of the behavior of realistic scale fires in spacecraft based on the limited low-g testing to date. As a result, spacecraft fire safety protocols are necessarily very conservative and costly. Future crewed missions are expected to be longer in duration than previous exploration missions outside of low-earth orbit and accordingly, more complex in terms of operations, logistics, and safety. This will increase the challenge of ensuring a fire-safe environment for the crew throughout the mission. Based on our fundamental uncertainty of the behavior of fires in low-gravity, the need for realistic scale testing at reduced gravity has been demonstrated. To address this concern, a spacecraft fire safety research project is underway to reduce the uncertainty and risk in the design of spacecraft fire safety systems by testing at nearly full scale in low-gravity. This project is supported by the NASA Advanced Exploration Systems Program Office in the Human Exploration and Operations Mission Directorate. The activity of this project is supported by an international topical team of fire experts from other space agencies to maximize the utility of the data and to ensure the widest possible scrutiny of the concept. The large-scale space flight experiment will be conducted on three missions; each in an Orbital Sciences Corporation Cygnus vehicle after it has deberthed from the ISS. Although the experiment will need to meet rigorous safety requirements to ensure the carrier vehicle does not sustain damage, the absence of a crew allows the fire products to be released into the cabin. The tests will be fully automated with the data downlinked at the conclusion of the test before the Cygnus vehicle reenters the

  16. Co-firing of coal with biomass and waste in full-scale suspension-fired boilers

    Energy Technology Data Exchange (ETDEWEB)

    Dam-Johansen, Kim; Frandsen, Flemming J.; Jensen, Peter A.; Jensen, Anker D. [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of chemical and Biochemical Engineering

    2013-07-01

    The energy policy in Denmark has for many years focused on lowering the net CO{sub 2} emission from heat and power production by replacing fossil fuels by renewable resources. This has been done by developing dedicated grate-fired boilers for biomass and waste fuels but also by developing coal-based suspension-fired boilers to accept still higher fractions of biomass or waste material as fuels. This last development has been challenging of many reasons, including pre-treatment of fuels, and solving potential emission and operational problems during the simultaneous development of supercritical steam cycles with steam temperatures close to 600 C, providing power efficiencies close to 50% (Hein KRG, Sustainable energy supply and environment protection - strategies, resources and technologies. In: Gupta R, Wall T, Hupa M, Wigley F, Tillman D, Frandsen FJ (eds) Proceedings of international conference on impact of fuel quality on power production and the environment, Banff Conference Centre, Banff, Alberta, Canada, 29 Sept-4 Oct, 2008). For 25 years the CHEC (Combustion and Harmful Emission Control) Research Centre at DTU Chemical Engineering, has attained a leading role in research, supporting power producing industry, plant owners and boiler manufacturers to optimize design and operation and minimize cost and environmental impact using alternative fuels in suspension fired boilers. Our contribution has been made via a combination of full-scale measuring campaigns, pilot-scale studies, lab-scale measurements and modeling tools. The research conducted has addressed many issues important for co-firing, i.e. fuel processing, ash induced boiler deposit formation and corrosion, boiler chamber fuel conversion and emission formation, influence on flue gas cleaning equipment and the utilization of residual products. This chapter provides an overview of research activities, aiming at increasing biomass shares during co-firing in suspension, conducted in close collaboration with

  17. Detecting Local Drivers of Fire Cycle Heterogeneity in Boreal Forests: A Scale Issue

    Directory of Open Access Journals (Sweden)

    Annie Claude Bélisle

    2016-07-01

    Full Text Available Severe crown fires are determining disturbances for the composition and structure of boreal forests in North America. Fire cycle (FC associations with continental climate gradients are well known, but smaller scale controls remain poorly documented. Using a time since fire map (time scale of 300 years, the study aims to assess the relative contributions of local and regional controls on FC and to describe the relationship between FC heterogeneity and vegetation patterns. The study area, located in boreal eastern North America, was partitioned into watersheds according to five scales going from local (3 km2 to landscape (2800 km2 scales. Using survival analysis, we observed that dry surficial deposits and hydrography density better predict FC when measured at the local scale, while terrain complexity and slope position perform better when measured at the middle and landscape scales. The most parsimonious model was selected according to the Akaike information criterion to predict FC throughout the study area. We detected two FC zones, one short (159 years and one long (303 years, with specific age structures and tree compositions. We argue that the local heterogeneity of the fire regime contributes to ecosystem diversity and must be considered in ecosystem management.

  18. VT Cable Systems 2005

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The VT Cable System dataset (CABLE2005) includes lines depicting the extent of Vermont's cable system as of 12/31/2005. Numerous cable companies...

  19. VT Cable Systems 2007

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The VT Cable System dataset (CABLE2007) includes lines depicting the extent of Vermont's cable system as of 12/31/2007. Numerous cable companies...

  20. Scaling laws and complexity in fire regimes [Chapter 2

    Science.gov (United States)

    Donald McKenzie; Maureen Kennedy

    2011-01-01

    Use of scaling terminology and concepts in ecology evolved rapidly from rare occurrences in the early 1980s to a central idea by the early 1990s (Allen and Hoekstra 1992; Levin 1992; Peterson and Parker 1998). In landscape ecology, use of "scale" frequently connotes explicitly spatial considerations (Dungan et al. 2002), notably grain and extent. More...

  1. Analysis of Forest Fires by means of Pseudo Phase Plane and Multidimensional Scaling Methods

    Directory of Open Access Journals (Sweden)

    J. A. Tenreiro Machado

    2014-01-01

    Full Text Available Forest fires dynamics is often characterized by the absence of a characteristic length-scale, long range correlations in space and time, and long memory, which are features also associated with fractional order systems. In this paper a public domain forest fires catalogue, containing information of events for Portugal, covering the period from 1980 up to 2012, is tackled. The events are modelled as time series of Dirac impulses with amplitude proportional to the burnt area. The time series are viewed as the system output and are interpreted as a manifestation of the system dynamics. In the first phase we use the pseudo phase plane (PPP technique to describe forest fires dynamics. In the second phase we use multidimensional scaling (MDS visualization tools. The PPP allows the representation of forest fires dynamics in two-dimensional space, by taking time series representative of the phenomena. The MDS approach generates maps where objects that are perceived to be similar to each other are placed on the map forming clusters. The results are analysed in order to extract relationships among the data and to better understand forest fires behaviour.

  2. Multi-scale controls of historical forest-fire regimes: new insights from fire-scar networks

    Science.gov (United States)

    Donald A. Falk; Emily K. Heyerdahl; Peter M. Brown; Calvin Farris; Peter Z. Fule; Donald McKenzie; Thomas W. Swetnam; Alan H. Taylor; Megan L. Van Horne

    2011-01-01

    Anticipating future forest-fire regimes under changing climate requires that scientists and natural resource managers understand the factors that control fire across space and time. Fire scars—proxy records of fires, formed in the growth rings of long-lived trees—provide an annually accurate window into past low-severity fire regimes. In western North America, networks...

  3. Measuring wildland fire leadership: the crewmember perceived leadership scale

    Science.gov (United States)

    Alexis L. Waldron; David P. Schary; Bradley J. Cardinal

    2015-01-01

    The aims of this research were to develop and test a scale used to measure leadership in wildland firefighting using two samples of USA wildland firefighters. The first collection of data occurred in the spring and early summer and consisted of an online survey. The second set of data was collected towards late summer and early fall (autumn). The second set of...

  4. Landscape-scale effects of fire severity on mixed-conifer and red fir forest structure in Yosemite National Park

    Science.gov (United States)

    Kane, Van R.; Lutz, James A.; Roberts, Susan L.; Smith, Douglas F.; McGaughey, Robert J.; Povak, Nicholas A.; Brooks, Matthew L.

    2013-01-01

    While fire shapes the structure of forests and acts as a keystone process, the details of how fire modifies forest structure have been difficult to evaluate because of the complexity of interactions between fires and forests. We studied this relationship across 69.2 km2 of Yosemite National Park, USA, that was subject to 32 fires ⩾40 ha between 1984 and 2010. Forests types included ponderosa pine (Pinus ponderosa), white fir-sugar pine (Abies concolor/Pinus lambertiana), and red fir (Abies magnifica). We estimated and stratified burned area by fire severity using the Landsat-derived Relativized differenced Normalized Burn Ratio (RdNBR). Airborne LiDAR data, acquired in July 2010, measured the vertical and horizontal structure of canopy material and landscape patterning of canopy patches and gaps. Increasing fire severity changed structure at the scale of fire severity patches, the arrangement of canopy patches and gaps within fire severity patches, and vertically within tree clumps. Each forest type showed an individual trajectory of structural change with increasing fire severity. As a result, the relationship between estimates of fire severity such as RdNBR and actual changes appears to vary among forest types. We found three arrangements of canopy patches and gaps associated with different fire severities: canopy-gap arrangements in which gaps were enclosed in otherwise continuous canopy (typically unburned and low fire severities); patch-gap arrangements in which tree clumps and gaps alternated and neither dominated (typically moderate fire severity); and open-patch arrangements in which trees were scattered across open areas (typically high fire severity). Compared to stands outside fire perimeters, increasing fire severity generally resulted first in loss of canopy cover in lower height strata and increased number and size of gaps, then in loss of canopy cover in higher height strata, and eventually the transition to open areas with few or no trees. However

  5. Intermediate-scale Fire Performance of Composite Panels under Varying Loads

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Alexander [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jernigan, Dann A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Dodd, Amanda B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-04-01

    New aircraft are being designed with increasing quantities of composite materials used in their construction. Different from the more traditional metals, composites have a higher propensity to burn. This presents a challenge to transportation safety analyses, as the aircraft structure now represents an additional fuel source involved in the fire scenario. Most of the historical fire testing of composite materials is aime d at studying kinetics, flammability or yield strength under fire conditions. Most of this testing is small - scale. Heterogeneous reactions are often length - scale dependent, and this is thought to be particularly true for composites which exhibit signific ant microscopic dynamics that can affect macro - scale behavior. We have designed a series of tests to evaluate composite materials under various structural loading conditions with a consistent thermal condition. We have measured mass - loss , heat flux, and temperature throughout the experiments. Several types of panels have been tested, including simple composite panels, and sandwich panels. The main objective of the testing was to understand the importance of the structural loading on a composite to its b ehavior in response to fire - like conditions. During flaming combustion at early times, there are some features of the panel decomposition that are unique to the type of loading imposed on the panels. At load levels tested, fiber reaction rates at later t imes appear to be independent of the initial structural loading.

  6. Modeling multiple time scale firing rate adaptation in a neural network of local field potentials.

    Science.gov (United States)

    Lundstrom, Brian Nils

    2015-02-01

    In response to stimulus changes, the firing rates of many neurons adapt, such that stimulus change is emphasized. Previous work has emphasized that rate adaptation can span a wide range of time scales and produce time scale invariant power law adaptation. However, neuronal rate adaptation is typically modeled using single time scale dynamics, and constructing a conductance-based model with arbitrary adaptation dynamics is nontrivial. Here, a modeling approach is developed in which firing rate adaptation, or spike frequency adaptation, can be understood as a filtering of slow stimulus statistics. Adaptation dynamics are modeled by a stimulus filter, and quantified by measuring the phase leads of the firing rate in response to varying input frequencies. Arbitrary adaptation dynamics are approximated by a set of weighted exponentials with parameters obtained by fitting to a desired filter. With this approach it is straightforward to assess the effect of multiple time scale adaptation dynamics on neural networks. To demonstrate this, single time scale and power law adaptation were added to a network model of local field potentials. Rate adaptation enhanced the slow oscillations of the network and flattened the output power spectrum, dampening intrinsic network frequencies. Thus, rate adaptation may play an important role in network dynamics.

  7. Superconductor cable

    Science.gov (United States)

    Smith, Jr., Darrell F.; Lake, Bill L.; Ballinger, Ronald G.

    1988-01-01

    A superconducting cable comprising an in-situ-formed type II superconductor, e.g. Nb.sub.3 Sn, in association with a stabilizing conductor both in heat transfer relationship with at least one passage adapted to carry liquified gaseous refrigerant. The conductor and said at least one passage are enclosed by a sheath comprising an alloy consisting essentially of about 49% nickel, about 4% chromium, about 3% niobium, about 1.4% titanium, about 1% aluminum, balance essentially iron.

  8. Environmentally induced amplitude death and firing provocation in large-scale networks of neuronal systems

    Science.gov (United States)

    Pankratova, Evgeniya V.; Kalyakulina, Alena I.

    2016-12-01

    We study the dynamics of multielement neuronal systems taking into account both the direct interaction between the cells via linear coupling and nondiffusive cell-to-cell communication via common environment. For the cells exhibiting individual bursting behavior, we have revealed the dependence of the network activity on its scale. Particularly, we show that small-scale networks demonstrate the inability to maintain complicated oscillations: for a small number of elements in an ensemble, the phenomenon of amplitude death is observed. The existence of threshold network scales and mechanisms causing firing in artificial and real multielement neural networks, as well as their significance for biological applications, are discussed.

  9. VT Cable Systems 2013

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The VT Cable dataset (CABLE2013) includes lines depicting the extent of Vermont's cable modem broadband system as of 6/30/2013 in addition to...

  10. Increased fire frequency promotes stronger spatial genetic structure and natural selection at regional and local scales in Pinus halepensis Mill.

    Science.gov (United States)

    Budde, Katharina B; González-Martínez, Santiago C; Navascués, Miguel; Burgarella, Concetta; Mosca, Elena; Lorenzo, Zaida; Zabal-Aguirre, Mario; Vendramin, Giovanni G; Verdú, Miguel; Pausas, Juli G; Heuertz, Myriam

    2017-04-01

    The recurrence of wildfires is predicted to increase due to global climate change, resulting in severe impacts on biodiversity and ecosystem functioning. Recurrent fires can drive plant adaptation and reduce genetic diversity; however, the underlying population genetic processes have not been studied in detail. In this study, the neutral and adaptive evolutionary effects of contrasting fire regimes were examined in the keystone tree species Pinus halepensis Mill. (Aleppo pine), a fire-adapted conifer. The genetic diversity, demographic history and spatial genetic structure were assessed at local (within-population) and regional scales for populations exposed to different crown fire frequencies. Eight natural P. halepensis stands were sampled in the east of the Iberian Peninsula, five of them in a region exposed to frequent crown fires (HiFi) and three of them in an adjacent region with a low frequency of crown fires (LoFi). Samples were genotyped at nine neutral simple sequence repeats (SSRs) and at 251 single nucleotide polymorphisms (SNPs) from coding regions, some of them potentially important for fire adaptation. Fire regime had no effects on genetic diversity or demographic history. Three high-differentiation outlier SNPs were identified between HiFi and LoFi stands, suggesting fire-related selection at the regional scale. At the local scale, fine-scale spatial genetic structure (SGS) was overall weak as expected for a wind-pollinated and wind-dispersed tree species. HiFi stands displayed a stronger SGS than LoFi stands at SNPs, which probably reflected the simultaneous post-fire recruitment of co-dispersed related seeds. SNPs with exceptionally strong SGS, a proxy for microenvironmental selection, were only reliably identified under the HiFi regime. An increasing fire frequency as predicted due to global change can promote increased SGS with stronger family structures and alter natural selection in P. halepensis and in plants with similar life history traits.

  11. Breed locally, disperse globally: fine-scale genetic structure despite landscape-scale panmixia in a fire-specialist.

    Directory of Open Access Journals (Sweden)

    Jennifer C Pierson

    Full Text Available An exciting advance in the understanding of metapopulation dynamics has been the investigation of how populations respond to ephemeral patches that go 'extinct' during the lifetime of an individual. Previous research has shown that this scenario leads to genetic homogenization across large spatial scales. However, little is known about fine-scale genetic structuring or how this changes over time in ephemeral patches. We predicted that species that specialize on ephemeral habitats will delay dispersal to exploit natal habitat patches while resources are plentiful and thus display fine-scale structure. To investigate this idea, we evaluated the effect of frequent colonization of ephemeral habitats on the fine-scale genetic structure of a fire specialist, the black-backed woodpecker (Picoides arcticus and found a pattern of fine-scale genetic structure. We then tested for differences in spatial structure between sexes and detected a pattern consistent with male-biased dispersal. We also detected a temporal increase in relatedness among individuals within newly burned forest patches. Our results indicate that specialist species that outlive their ephemeral patches can accrue significant fine-scale spatial structure that does not necessarily affect spatial structure at larger scales. This highlights the importance of both spatial and temporal scale considerations in both sampling and data interpretation of molecular genetic results.

  12. Static and dynamic controls on fire activity at moderate spatial and temporal scales in the Alaskan boreal forest

    Science.gov (United States)

    Barrett, Kirsten; Loboda, Tatiana; McGuire, A. David; Genet, Hélène; Hoy, Elizabeth; Kasischke, Eric

    2016-01-01

    Wildfire, a dominant disturbance in boreal forests, is highly variable in occurrence and behavior at multiple spatiotemporal scales. New data sets provide more detailed spatial and temporal observations of active fires and the post-burn environment in Alaska. In this study, we employ some of these new data to analyze variations in fire activity by developing three explanatory models to examine the occurrence of (1) seasonal periods of elevated fire activity using the number of MODIS active fire detections data set (MCD14DL) within an 11-day moving window, (2) unburned patches within a burned area using the Monitoring Trends in Burn Severity fire severity product, and (3) short-to-moderate interval (fires using areas of burned area overlap in the Alaska Large Fire Database. Explanatory variables for these three models included dynamic variables that can change over the course of the fire season, such as weather and burn date, as well as static variables that remain constant over a fire season, such as topography, drainage, vegetation cover, and fire history. We found that seasonal periods of high fire activity are associated with both seasonal timing and aggregated weather conditions, as well as the landscape composition of areas that are burning. Important static inputs to the model of seasonal fire activity indicate that when fire weather conditions are suitable, areas that typically resist fire (e.g., deciduous stands) may become more vulnerable to burning and therefore less effective as fire breaks. The occurrence of short-to-moderate interval fires appears to be primarily driven by weather conditions, as these were the only relevant explanatory variables in the model. The unique importance of weather in explaining short-to-moderate interval fires implies that fire return intervals (FRIs) will be sensitive to projected climate changes in the region. Unburned patches occur most often in younger stands, which may be related to a greater deciduous fraction of

  13. Improvement of a high current DC power supply system for testing the large scaled superconducting cables and magnets

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Shuichi; Chikaraishi, Hirotaka; Tanahashi, Shugo [and others

    1993-11-01

    A dc 75 kA power supply system was constructed to test the superconducting (SC) R and D cables and magnets for the Large Helical Device. It consists of three 25 kA unit banks. A unit bank has two double-star-rectifier connections with the inter-phase reactors. A digital feedback control method is applied to the automatic current regulation (ACR) in each unit bank. For shortening the dead time of the feedback process, a new algorithm of a digital phase controller for the ACR is investigated. A Bode diagram of the feedback process is directly measured. It is confirmed that the dead time of the feedback process is reduced to one sixth, and that the feedback gain of PID compensation is improved by a factor of two from the original method. (author).

  14. Improvement of a high current dc power supply system for testing the large scaled superconducting cables and magnets

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Shuichi; Chikaraishi, Hirotaka; Tanahashi, Shugo [National Inst. for Fusion Science, Toki, Gifu (Japan)] [and others

    1994-07-01

    A dc 75 kA power supply system was constructed to test the SC (superconducting) R and D (research and development) cables and magnets for the Large Helical Device (LHD). It consists of three 25 kA unit banks. A unit bank has two double-star-rectifier connections with the inter-phase reactors. A digital feedback control method is applied to the automatic current regulation (ACR) in each unit bank. For shortening the dead time of the feedback process, a new algorithm of a digital phase controller for the ACR is investigated. A Bode diagram of the feedback process is directly measured. It is confirmed that the dead time of the feedback process is reduced to one sixth, and that the feedback gain of PID (proportional, integral and differential) compensation is improved by a factor of two from the original method.

  15. Quantifying differences between computational results and measurements in the case of a large-scale well-confined fire scenario

    Energy Technology Data Exchange (ETDEWEB)

    Audouin, L. [IRSN, St Paul-Lez-Durance (France); Chandra, L. [NRG, Petten (Netherlands); Consalvi, J.-L. [IUSTI, Marseille (France); Gay, L. [EDF R and D, Chatou (France); Gorza, E. [TRACTEBEL Engineering, Brussels (Belgium); Hohm, V. [iBMB, Braunschweig (Germany); Hostikka, S. [VTT, Espoo (Finland); Ito, T. [JNES, Tokyo (Japan); Klein-Hessling, W. [GRS, Koeln (Germany); Lallemand, C. [DGA, Toulon (France); Magnusson, T. [Vattenfall, Stockholm (Sweden); Noterman, N. [Bel V (Belgium); Park, J.S. [KINS, Daejeon (Korea, Republic of); Peco, J. [CSN, Madrid (Spain); Rigollet, L. [IRSN, St Paul-Lez-Durance (France); Suard, S., E-mail: sylvain.suard@irsn.f [IRSN, St Paul-Lez-Durance (France); Van-Hees, P. [LUND University, Lund (Sweden)

    2011-01-15

    Research Highlights: We performed a numerical benchmark in the framework of an OECD experimental program of a pool fire in a well-confined compartment. The benchmark involves 17 participants using 8 fire models, 3 CFD and 5 zone models. We investigated the capabilities of validation metrics for a real large-scale fire. Six quantities were compared during the whole fire duration. It is important to consider more than one metric for the validation process. - Abstract: The objective of this work was to quantify comparisons between several computational results and measurements performed during a pool fire scenario in a well-confined compartment. This collaborative work was initiated under the framework of the OECD fire research program and involves the most frequently used fire models in the fire community, including field and zone models. The experimental scenario was conducted at the French Institut de Radioprotection et de Surete Nucleaire (IRSN) and deals with a full-scale liquid pool fire in a confined and mechanically ventilated compartment representative for nuclear plants. The practical use of different metric operators and their ability to report the capabilities of fire models are presented. The quantitative comparisons between measurements and numerical results obtained from 'open' calculations concern six important quantities from a safety viewpoint: gas temperature, oxygen concentration, wall temperature, total heat flux, compartment pressure and ventilation flow rate during the whole fire duration. The results indicate that it is important to use more than one metric for the validation process in order to get information on the uncertainties associated with different aspects of fire safety.

  16. Decadal time-scale monitoring of forest fires in Similipal Biosphere Reserve, India using remote sensing and GIS.

    Science.gov (United States)

    Saranya, K R L; Reddy, C Sudhakar; Rao, P V V Prasada; Jha, C S

    2014-05-01

    Analyzing the spatial extent and distribution of forest fires is essential for sustainable forest resource management. There is no comprehensive data existing on forest fires on a regular basis in Biosphere Reserves of India. The present work have been carried out to locate and estimate the spatial extent of forest burnt areas using Resourcesat-1 data and fire frequency covering decadal fire events (2004-2013) in Similipal Biosphere Reserve. The anomalous quantity of forest burnt area was recorded during 2009 as 1,014.7 km(2). There was inconsistency in the fire susceptibility across the different vegetation types. The spatial analysis of burnt area shows that an area of 34.2 % of dry deciduous forests, followed by tree savannah, shrub savannah, and grasslands affected by fires in 2013. The analysis based on decadal time scale satellite data reveals that an area of 2,175.9 km(2) (59.6 % of total vegetation cover) has been affected by varied rate of frequency of forest fires. Fire density pattern indicates low count of burnt area patches in 2013 estimated at 1,017 and high count at 1,916 in 2004. An estimate of fire risk area over a decade identifies 12.2 km(2) is experiencing an annual fire damage. Summing the fire frequency data across the grids (each 1 km(2)) indicates 1,211 (26 %) grids are having very high disturbance regimes due to repeated fires in all the 10 years, followed by 711 grids in 9 years and 418 in 8 years and 382 in 7 years. The spatial database offers excellent opportunities to understand the ecological impact of fires on biodiversity and is helpful in formulating conservation action plans.

  17. Experimental study on the influence of different thermal insulation materials on the fire dynamics in a reduced-scale enclosure

    DEFF Research Database (Denmark)

    Leisted, Rolff Ripke; Sørensen, Martin X.; Jomaas, Grunde

    2017-01-01

    in the fire behavior, depending on whether the enclosures were constructed of panels filled with SW or PIR insulation material. The mass losses of the insulation materials showed significant contribution from the PIR cores, regardless of fire load and the non-structural damage. The qualitative behavior...... in the full scale tests than in the scaled experiments. Therefore, it can be concluded that when the energy contribution from the core material remained negligible compared to the gas burner, the measured parameters matched quite well. Therefore, if the insulating core material does not dominate the fire...

  18. The wildland fuel cell concept: an approach to characterize fine-scale variation in fuels and fire in frequently burned longleaf pine forests

    Science.gov (United States)

    J. Kevin Hiers; Joseph J. O’Brien; R. J. Mitchell; John M. Grego; E. Louise Loudermilk

    2009-01-01

    In ecosystems with frequent surface fire regimes, fire and fuel heterogeneity has been largely overlookedowing to the lack of unburned patches and the difficulty in measuring fire behavior at fine scales (0.1–10 m). The diversevegetation in these ecosystems varies at these fine scales. This diversity could be...

  19. CABLES MUSCULARES

    Directory of Open Access Journals (Sweden)

    Alejandro Gómez

    Full Text Available Los cables musculares o fibras de nitinol presentan una excelente alternativa a los actuadores convencionales, con una fuerza de actuación muy alta, equivalente a la de los actuadores hidráulicos, proporcionalmente a su peso, además de su acción silenciosa. Este material, inventado en 1963, aún no es muy conocido y de ahí que se haya realizado una recopilación de sus propiedades. Entre ellas, la temperatura de transición es la más importante, por ser la que activa la aleación. Muchos sistemas se han creado para alcanzar adecuadamente la temperatura de transición, y también se continúa en la investigación de métodos que ayuden a lograr un control preciso del movimiento de la aleación con memoria de forma (SMA.

  20. Landscape management of fire and grazing regimes alters the fine-scale habitat utilisation by feral cats.

    Science.gov (United States)

    McGregor, Hugh W; Legge, Sarah; Jones, Menna E; Johnson, Christopher N

    2014-01-01

    Intensification of fires and grazing by large herbivores has caused population declines in small vertebrates in many ecosystems worldwide. Impacts are rarely direct, and usually appear driven via indirect pathways, such as changes to predator-prey dynamics. Fire events and grazing may improve habitat and/or hunting success for the predators of small mammals, however, such impacts have not been documented. To test for such an interaction, we investigated fine-scale habitat selection by feral cats in relation to fire, grazing and small-mammal abundance. Our study was conducted in north-western Australia, where small mammal populations are sensitive to changes in fire and grazing management. We deployed GPS collars on 32 cats in landscapes with contrasting fire and grazing treatments. Fine-scale habitat selection was determined using discrete choice modelling of cat movements. We found that cats selected areas with open grass cover, including heavily-grazed areas. They strongly selected for areas recently burnt by intense fires, but only in habitats that typically support high abundance of small mammals. Intense fires and grazing by introduced herbivores created conditions that are favoured by cats, probably because their hunting success is improved. This mechanism could explain why, in northern Australia, impacts of feral cats on small mammals might have increased. Our results suggest the impact of feral cats could be reduced in most ecosystems by maximising grass cover, minimising the incidence of intense fires, and reducing grazing by large herbivores.

  1. Landscape management of fire and grazing regimes alters the fine-scale habitat utilisation by feral cats.

    Directory of Open Access Journals (Sweden)

    Hugh W McGregor

    Full Text Available Intensification of fires and grazing by large herbivores has caused population declines in small vertebrates in many ecosystems worldwide. Impacts are rarely direct, and usually appear driven via indirect pathways, such as changes to predator-prey dynamics. Fire events and grazing may improve habitat and/or hunting success for the predators of small mammals, however, such impacts have not been documented. To test for such an interaction, we investigated fine-scale habitat selection by feral cats in relation to fire, grazing and small-mammal abundance. Our study was conducted in north-western Australia, where small mammal populations are sensitive to changes in fire and grazing management. We deployed GPS collars on 32 cats in landscapes with contrasting fire and grazing treatments. Fine-scale habitat selection was determined using discrete choice modelling of cat movements. We found that cats selected areas with open grass cover, including heavily-grazed areas. They strongly selected for areas recently burnt by intense fires, but only in habitats that typically support high abundance of small mammals. Intense fires and grazing by introduced herbivores created conditions that are favoured by cats, probably because their hunting success is improved. This mechanism could explain why, in northern Australia, impacts of feral cats on small mammals might have increased. Our results suggest the impact of feral cats could be reduced in most ecosystems by maximising grass cover, minimising the incidence of intense fires, and reducing grazing by large herbivores.

  2. Landscape-scale quantification of fire-induced change in canopy cover following mountain pine beetle outbreak and timber harvest

    Science.gov (United States)

    McCarley, T. Ryan; Kolden, Crystal A.; Vaillant, Nicole M.; Hudak, Andrew T.; Smith, Alistair M.S.; Kreitler, Jason R.

    2017-01-01

    Across the western United States, the three primary drivers of tree mortality and carbon balance are bark beetles, timber harvest, and wildfire. While these agents of forest change frequently overlap, uncertainty remains regarding their interactions and influence on specific subsequent fire effects such as change in canopy cover. Acquisition of pre- and post-fire Light Detection and Ranging (LiDAR) data on the 2012 Pole Creek Fire in central Oregon provided an opportunity to isolate and quantify fire effects coincident with specific agents of change. This study characterizes the influence of pre-fire mountain pine beetle (MPB; Dendroctonus ponderosae) and timber harvest disturbances on LiDAR-estimated change in canopy cover. Observed canopy loss from fire was greater (higher severity) in areas experiencing pre-fire MPB (Δ 18.8%CC) than fire-only (Δ 11.1%CC). Additionally, increasing MPB intensity was directly related to greater canopy loss. Canopy loss was lower for all areas of pre-fire timber harvest (Δ 3.9%CC) than for fire-only, but among harvested areas, the greatest change was observed in the oldest treatments and the most intensive treatments [i.e., stand clearcut (Δ 5.0%CC) and combination of shelterwood establishment cuts and shelterwood removal cuts (Δ 7.7%CC)]. These results highlight the importance of accounting for and understanding the impact of pre-fire agents of change such as MPB and timber harvest on subsequent fire effects in land management planning. This work also demonstrates the utility of multi-temporal LiDAR as a tool for quantifying these landscape-scale interactions.

  3. A PSO Driven Intelligent Model Updating and Parameter Identification Scheme for Cable-Damper System

    Directory of Open Access Journals (Sweden)

    Danhui Dan

    2015-01-01

    Full Text Available The precise measurement of the cable force is very important for monitoring and evaluating the operation status of cable structures such as cable-stayed bridges. The cable system should be installed with lateral dampers to reduce the vibration, which affects the precise measurement of the cable force and other cable parameters. This paper suggests a cable model updating calculation scheme driven by the particle swarm optimization (PSO algorithm. By establishing a finite element model considering the static geometric nonlinearity and stress-stiffening effect firstly, an automatically finite element method model updating powered by PSO algorithm is proposed, with the aims to identify the cable force and relevant parameters of cable-damper system precisely. Both numerical case studies and full-scale cable tests indicated that, after two rounds of updating process, the algorithm can accurately identify the cable force, moment of inertia, and damping coefficient of the cable-damper system.

  4. Water, land, fire, and forest: Multi-scale determinants of rainforests in the Australian monsoon tropics.

    Science.gov (United States)

    Ondei, Stefania; Prior, Lynda D; Williamson, Grant J; Vigilante, Tom; Bowman, David M J S

    2017-03-01

    The small rainforest fragments found in savanna landscapes are powerful, yet often overlooked, model systems to understand the controls of these contrasting ecosystems. We analyzed the relative effect of climatic variables on rainforest density at a subcontinental level, and employed high-resolution, regional-level analyses to assess the importance of landscape settings and fire activity in determining rainforest density in a frequently burnt Australian savanna landscape. Estimates of rainforest density (ha/km 2 ) across the Northern Territory and Western Australia, derived from preexisting maps, were used to calculate the correlations between rainforest density and climatic variables. A detailed map of the northern Kimberley (Western Australia) rainforests was generated and analyzed to determine the importance of geology and topography in controlling rainforests, and to contrast rainforest density on frequently burnt mainland and nearby islands. In the northwestern Australian, tropics rainforest density was positively correlated with rainfall and moisture index, and negatively correlated with potential evapotranspiration. At a regional scale, rainforests showed preference for complex topographic positions and more fertile geology. Compared with mainland areas, islands had significantly lower fire activity, with no differences between terrain types. They also displayed substantially higher rainforest density, even on level terrain where geomorphological processes do not concentrate nutrients or water. Our multi-scale approach corroborates previous studies that suggest moist climate, infrequent fires, and geology are important stabilizing factors that allow rainforest fragments to persist in savanna landscapes. These factors need to be incorporated in models to predict the future extent of savannas and rainforests under climate change.

  5. How do you like them cables?

    CERN Multimedia

    Sergei Malyukov

    Cabling work is not for clautrophobic people! Cables are like the blood vessels and nervous system of ATLAS. With the help of all these cables, we can power ATLAS, control the detector and read out the data. Like the human blood vessels, they penetrate inside the ATLAS volume, reaching each of its elements. The ATLAS developers started to think about design of services, cables and pipes at the very first stages of the project. The cabling project has been developing most intensively during the last five years, passing through the projection and CAD design phases, then the installation of cable trays and finally the cables. The cable installation itself took two and a half years and was done by teams of technicians from several institutes from Russia, the Czech Republic and Poland. Here are some numbers to illustrate the scale of the ATLAS cabling system. More than 25000 optical fiber channels are used for reading the information from the sub-detectors and delivering the timing signals. The total numbe...

  6. Natural and social factors influencing forest fire occurrence at a local spatial scale

    Science.gov (United States)

    Maria Luisa Chas-Amil; Julia M. Touza; Jeffrey P. Prestemon; Colin J. McClean

    2012-01-01

    Development of efficient forest fire policies requires an understanding of the underlying reasons behind forest fire ignitions. Globally, there is a close relationship between forest fires and human activities, i.e., fires understood as human events due to negligence (e.g., agricultural burning escapes), and deliberate actions (e.g., pyromania, revenge, land use change...

  7. Modeling Fire Occurrence at the City Scale: A Comparison between Geographically Weighted Regression and Global Linear Regression.

    Science.gov (United States)

    Song, Chao; Kwan, Mei-Po; Zhu, Jiping

    2017-04-08

    An increasing number of fires are occurring with the rapid development of cities, resulting in increased risk for human beings and the environment. This study compares geographically weighted regression-based models, including geographically weighted regression (GWR) and geographically and temporally weighted regression (GTWR), which integrates spatial and temporal effects and global linear regression models (LM) for modeling fire risk at the city scale. The results show that the road density and the spatial distribution of enterprises have the strongest influences on fire risk, which implies that we should focus on areas where roads and enterprises are densely clustered. In addition, locations with a large number of enterprises have fewer fire ignition records, probably because of strict management and prevention measures. A changing number of significant variables across space indicate that heterogeneity mainly exists in the northern and eastern rural and suburban areas of Hefei city, where human-related facilities or road construction are only clustered in the city sub-centers. GTWR can capture small changes in the spatiotemporal heterogeneity of the variables while GWR and LM cannot. An approach that integrates space and time enables us to better understand the dynamic changes in fire risk. Thus governments can use the results to manage fire safety at the city scale.

  8. Particle size distributions from laboratory-scale biomass fires using fast response instruments

    Directory of Open Access Journals (Sweden)

    S. Hosseini

    2010-08-01

    Full Text Available Particle size distribution from biomass combustion is an important parameter as it affects air quality, climate modelling and health effects. To date, particle size distributions reported from prior studies vary not only due to difference in fuels but also difference in experimental conditions. This study aims to report characteristics of particle size distributions in well controlled repeatable lab scale biomass fires for southwestern United States fuels with focus on chaparral. The combustion laboratory at the United States Department of Agriculture-Forest Service's Fire Science Laboratory (USDA-FSL, Missoula, MT provided a repeatable combustion and dilution environment ideal for measurements. For a variety of fuels tested the major mode of particle size distribution was in the range of 29 to 52 nm, which is attributable to dilution of the fresh smoke. Comparing mass size distribution from FMPS and APS measurement 51–68% of particle mass was attributable to the particles ranging from 0.5 to 10 μm for PM10. Geometric mean diameter rapidly increased during flaming and gradually decreased during mixed and smoldering phase combustion. Most fuels produced a unimodal distribution during flaming phase and strong biomodal distribution during smoldering phase. The mode of combustion (flaming, mixed and smoldering could be better distinguished using the slopes in MCE (Modified Combustion Efficiency vs. geometric mean diameter than only using MCE values.

  9. Cable Supported Bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    Cable supported bridges in the form of suspension bridges and cable-stayed bridges are distinguished by their ability to overcome large spans.The book concentrates on the synthesis of cable supported bridges, covering both design and construction aspects. The analytical part covers simple methods...... to quantify the different structural configurations and allows a preliminary optimization of the main structure.Included are the most recent advances in structural design, corrosion protection of cables, aerodynamic safety, and erection procedures....

  10. Molds for cable dielectrics

    Science.gov (United States)

    Roose, L.D.

    1996-12-10

    Molds for use in making end moldings for high-voltage cables are described wherein the dielectric insulator of a cable is heated and molded to conform to a desired shape. As a consequence, high quality substantially bubble-free cable connectors suitable for mating to premanufactured fittings are made. 5 figs.

  11. How to arrange fuel supply on large scale wood fired CHP

    Energy Technology Data Exchange (ETDEWEB)

    Nickull, S. [Oy Alholmens Kraft Ab, Jakobstad (Finland)

    2001-09-01

    During the last years the utilisation of biofuels on large scale has been focused on forest industry sites where large amounts of biomass is available. Now Alholmens Kraft is constructing the world's largest bio-fired power plant in Jakobstad/ Pietarsaari, Finland. The steam boiler will have a fuel capacity of 590 MW. The power plant will use wood-based biofuel such as bark, sawdust, wood chips, cut peat, along with coal as a reserve requirement. The electrical capacity of the new power station will be 240 MW in full condensing operations generating 100 MW process steam and 60 MW district heat. Business operations will begin in October 2001. (au)

  12. The effect of urban growth on landscape-scale restoration for a fire-dependent songbird.

    Science.gov (United States)

    Pickens, Bradley A; Marcus, Jeffrey F; Carpenter, John P; Anderson, Scott; Taillie, Paul J; Collazo, Jaime A

    2017-04-15

    A landscape-scale perspective on restoration ecology has been advocated, but few studies have informed restoration with landscape metrics or addressed broad-scale threats. Threats such as urban growth may affect restoration effectiveness in a landscape context. Here, we studied longleaf pine savanna in the rapidly urbanizing southeastern United States where a habitat-specialist bird, Bachman's sparrow (Peucaea aestivalis), is closely associated with savanna vegetation structure and frequent fire. Our objectives were to construct a species distribution model for Bachman's sparrow, determine the relationship between fire and urbanization, quantify the urban growth effect (2010-2090), identify potential restoration areas, and determine the interaction between restoration potential and urban growth by 2050. Number of patches, patch size, and isolation metrics were used to evaluate scenarios. The species distribution model was 88% accurate and emphasized multiscale canopy cover characteristics, fire, and percent habitat. Fires were less common urban areas, and this fire suppression effect exacerbated urban growth effects. For restoration scenarios, canopy cover reduction by 30% resulted in nearly double the amount of habitat compared to the prescribed fire scenario; canopy cover reduction resulted in larger patch sizes and less patch isolation compared to current conditions. The effect of urban growth on restoration scenarios was unequal. Seventy-four percent of restoration areas from the prescribed fire scenario overlapped with projected urban growth, whereas the canopy cover reduction scenario only overlapped by 9%. We emphasize the benefits of simultaneously considering the effects of urban growth and landscape-scale restoration potential to promote a landscape with greater patch sizes and less isolation. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. Detonator cable initiation system safety investigation: Consequences of energizing the detonator and actuator cables

    Energy Technology Data Exchange (ETDEWEB)

    Osher, J.; Chau, H.; Von Holle, W.

    1994-03-01

    This study was performed to explore and assess the worst-case response of a W89-type weapons system, damaged so as to expose detonator and/or detonator safing strong link (DSSL) cables to the most extreme, credible lightning-discharge, environment. The test program used extremely high-current-level, fast-rise-time (1- to 2-{mu}s) discharges to simulate lightning strikes to either the exposed detonator or DSSL cables. Discharges with peak currents above 700 kA were required to explode test sections of detonator cable and launch a flyer fast enough potentially to detonate weapon high explosive (HE). Detonator-safing-strong-link (DSSL) cables were exploded in direct contact with hot LX-17 and Ultrafine TATB (UFTATB). At maximum charging voltage, the discharge system associated with the HE firing chamber exploded the cables at more than 600-kA peak current; however, neither LX-17 nor UFTATB detonated at 250{degree}C. Tests showed that intense surface arc discharges of more than 700 kA/cm in width across the surface of hot UFTATB [generally the more sensitive of the two insensitive high explosives (IHE)] could not initiate this hot IHE. As an extension to this study, we applied the same technique to test sections of the much-narrower but thicker-cover-layer W87 detonator cable. These tests were performed at the same initial stored electrical energy as that used for the W89 study. Because of the narrower cable conductor in the W87 cables, discharges greater than 550-kA peak current were sufficient to explode the cable and launch a fast flyer. In summary, we found that lightning strikes to exposed DSSL cables cannot directly detonate LX-17 or UFTATB even at high temperatures, and they pose no HE safety threat.

  14. How fuel treatment types, locations, and amounts impact landscape-scale fire behavior and carbon dynamics

    Science.gov (United States)

    Christopher A. Dicus; Kevin J. Osborne

    2015-01-01

    When managing for fire across a large landscape, the types of fuel treatments, the locations of treatments, and the percentage of the landscape being treated should all interact to impact not only potential fire size, but also carbon dynamics across that landscape. To investigate these interactions, we utilized a forest growth model (FVS-FFE) and fire simulation...

  15. Cable Aerodynamic Control

    DEFF Research Database (Denmark)

    Kleissl, Kenneth

    This dissertation investigates the possibility of preventing wind-induced cable vibrations on cable-stayed bridges using passive aerodynamic means in the form of cable surface modifications. Especially the phenomenon of rainwind induced vibrations, which is known as the most common type of these ......This dissertation investigates the possibility of preventing wind-induced cable vibrations on cable-stayed bridges using passive aerodynamic means in the form of cable surface modifications. Especially the phenomenon of rainwind induced vibrations, which is known as the most common type...... to a categorization of the different control technics together with an identification of two key mechanisms for reduction of the design drag force. During this project extensive experimental work examining the aerodynamics of the currently used cable surface modifications together with new innovative proposals have...

  16. The effects of hillslope-scale variability in burn severity on post-fire sediment delivery

    Science.gov (United States)

    Quinn, Dylan; Brooks, Erin; Dobre, Mariana; Lew, Roger; Robichaud, Peter; Elliot, William

    2017-04-01

    With the increasing frequency of wildfire and the costs associated with managing the burned landscapes, there is an increasing need for decision support tools that can be used to assess the effectiveness of targeted post-fire management strategies. The susceptibility of landscapes to post-fire soil erosion and runoff have been closely linked with the severity of the wildfire. Wildfire severity maps are often spatial complex and largely dependent upon total vegetative biomass, fuel moisture patterns, direction of burn, wind patterns, and other factors. The decision to apply targeted treatment to a specific landscape and the amount of resources dedicated to treating a landscape should ideally be based on the potential for excessive sediment delivery from a particular hillslope. Recent work has suggested that the delivery of sediment to a downstream water body from a hillslope will be highly influenced by the distribution of wildfire severity across a hillslope and that models that do not capture this hillslope scale variability would not provide reliable sediment and runoff predictions. In this project we compare detailed (10 m) grid-based model predictions to lumped and semi-lumped hillslope approaches where hydrologic parameters are fixed based on hillslope scale averaging techniques. We use the watershed scale version of the process-based Watershed Erosion Prediction Projection (WEPP) model and its GIS interface, GeoWEPP, to simulate the fire impacts on runoff and sediment delivery using burn severity maps at a watershed scale. The flowpath option in WEPP allows for the most detail representation of wildfire severity patterns (10 m) but depending upon the size of the watershed, simulations are time consuming and computational demanding. The hillslope version is a simpler approach which assigns wildfire severity based on the severity level that is assigned to the majority of the hillslope area. In the third approach we divided hillslopes in overland flow elements

  17. Quantifying the multi-scale response of avifauna to prescribed fire experiments in the southwest United States

    Science.gov (United States)

    Brett G. Dickson; Barry R. Noon; Curtis H. Flather; Stephanie Jentsch; William M. Block

    2009-01-01

    Landscape-scale disturbance events, including ecological restoration and fuel reduction activities, can modify habitat and affect relationships between species and their environment. To reduce the risk of uncharacteristic stand-replacing fires in the southwestern United States, land managers are implementing restoration and fuels treatments (e.g., mechanical thinning,...

  18. Fire activity as a function of fire–weather seasonal severity and antecedent climate across spatial scales in southern Europe and Pacific western USA

    Science.gov (United States)

    Urbieta, Itziar R.; Zavala, Gonzalo; Bedia, Joaquin; Gutierrez, Jose M.; San Miguel-Ayanz, Jesus; Camia, Andrea; Keeley, Jon E.; Moreno, Jose M.

    2015-01-01

    Climate has a strong influence on fire activity, varying across time and space. We analyzed the relationships between fire–weather conditions during the main fire season and antecedent water-balance conditions and fires in two Mediterranean-type regions with contrasted management histories: five southern countries of the European Union (EUMED)(all fires); the Pacific western coast of the USA (California and Oregon, PWUSA)(national forest fires). Total number of fires (≥1 ha), number of large fires (≥100 ha) and area burned were related to mean seasonal fire weather index (FWI), number of days over the 90th percentile of the FWI, and to the standardized precipitation-evapotranspiration index (SPEI) from the preceding 3 (spring) or 8 (autumn through spring) months. Calculations were made at three spatial aggregations in each area, and models related first-difference (year-to-year change) of fires and FWI/climate variables to minimize autocorrelation. An increase in mean seasonal FWI resulted in increases in the three fire variables across spatial scales in both regions. SPEI contributed little to explain fires, with few exceptions. Negative water-balance (dry) conditions from autumn through spring (SPEI8) were generally more important than positive conditions (moist) in spring (SPEI3), both of which contributed positively to fires. The R2 of the models generally improved with increasing area of aggregation. For total number of fires and area burned, the R2 of the models tended to decrease with increasing mean seasonal FWI. Thus, fires were more susceptible to change with climate variability in areas with less amenable conditions for fires (lower FWI) than in areas with higher mean FWI values. The relationships were similar in both regions, albeit weaker in PWUSA, probably due to the wider latitudinal gradient covered in PWUSA than in EUMED. The large variance explained by some of the models indicates that large-scale seasonal forecast could help anticipating

  19. 46 CFR 116.415 - Fire control boundaries.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Fire control boundaries. 116.415 Section 116.415... ARRANGEMENT Fire Protection § 116.415 Fire control boundaries. (a) Type and construction of fire control... Class 0 minutes (iv) Penetrations in B-Class fire control boundaries for electrical cables, pipes...

  20. Numerical modeling of laboratory-scale surface-to-crown fire transition

    Science.gov (United States)

    Castle, Drew Clayton

    Understanding the conditions leading to the transition of fire spread from a surface fuel to an elevated (crown) fuel is critical to effective fire risk assessment and management. Surface fires that successfully transition to crown fires can be very difficult to suppress, potentially leading to damages in the natural and built environments. This is relevant to chaparral shrub lands which are common throughout parts of the Southwest U.S. and represent a significant part of the wildland urban interface. The ability of the Wildland-Urban Interface Fire Dynamic Simulator (WFDS) to model surface-to-crown fire transition was evaluated through comparison to laboratory experiments. The WFDS model is being developed by the U.S. Forest Service (USFS) and the National Institute of Standards and Technology. The experiments were conducted at the USFS Forest Fire Laboratory in Riverside, California. The experiments measured the ignition of chamise (Adenostoma fasciculatum) crown fuel held above a surface fire spreading through excelsior fuel. Cases with different crown fuel bulk densities, crown fuel base heights, and imposed wind speeds were considered. Cold-flow simulations yielded wind speed profiles that closely matched the experimental measurements. Next, fire simulations with only the surface fuel were conducted to verify the rate of spread while factors such as substrate properties were varied. Finally, simulations with both a surface fuel and a crown fuel were completed. Examination of specific surface fire characteristics (rate of spread, flame angle, etc.) and the corresponding experimental surface fire behavior provided a basis for comparison of the factors most responsible for transition from a surface fire to the raised fuel ignition. The rate of spread was determined by tracking the flame in the Smokeview animations using a tool developed for tracking an actual flame in a video. WFDS simulations produced results in both surface fire spread and raised fuel bed

  1. Cable Tester Box

    Science.gov (United States)

    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.

  2. Optical Cable Design

    Science.gov (United States)

    Aggarwal, I. D.

    1984-08-01

    Optical cable applications can be divided into four major market segments. These are telecommunication, data, video and military communication. For the majority of the telecommunication, data, and video applications, a loose tube or loose ribbon design can be manufactured without incurring a microbending loss penalty. Fibre performance in the loose tube cables can be maximized by optimizing the lay length, tube dimension and pitch diameter. At present, high quality cables using both single and multimode fibre are being manufactured in volume with no additional microbending loss. For example, single and multimode cables with loss of 0.5 dB/km 1300 nm and very high bandwidths or low dispersion have been successfully installed in many cities. An example of this cable is shown in Figure 1. These cables have been used for direct buried, duct system, aerial or underwater installations.

  3. Cable suspended windmill

    Science.gov (United States)

    Farmer, Moses G. (Inventor)

    1990-01-01

    A windmill is disclosed which includes an airframe having an upwind end and a downwind end. The first rotor is rotatably connected to the airframe, and a generator is supported by the airframe and driven by the rotor. The airframe is supported vertically in an elevated disposition by poles which extend vertically upwardly from the ground and support cables which extend between the vertical poles. Suspension cables suspend the airframe from the support cable.

  4. Electrical power cable engineering

    CERN Document Server

    Thue, William A

    2011-01-01

    Fully updated, Electrical Power Cable Engineering, Third Edition again concentrates on the remarkably complex design, application, and preparation methods required to terminate and splice cables. This latest addition to the CRC Press Power Engineering series covers cutting-edge methods for design, manufacture, installation, operation, and maintenance of reliable power cable systems. It is based largely on feedback from experienced university lecturers who have taught courses on these very concepts.The book emphasizes methods to optimize vital design and installation of power cables used in the

  5. Valorization of stabilized river sediments in fired clay bricks: factory scale experiment.

    Science.gov (United States)

    Samara, Mazen; Lafhaj, Zoubeir; Chapiseau, Christophe

    2009-04-30

    The objective of this study is to demonstrate the practical use of polluted river sediments after treatment into brick production. Consequently, a full-scale industrial experiment was conducted at a brick factory in the north of France. Polluted sediment was stabilized by the Novosol process and then was introduced in the mix-design with a substitution ratio of 15% as a partial replacement of quartz sand. Approximately 15,000 perforated sediment-amended bricks were produced. The produced bricks were then subjected to several qualification tests (compressive strength, freeze and thaw resistance, water absorption). The results obtained showed that the substitution of quartz sand by treated sediment resulted in a significant increase in brick compressive strength and firing shrinkage, and in a decrease in porosity and water absorption. Moreover, leaching tests performed according to different standards on substituted brick samples showed that the quantities of heavy metals leached from crushed bricks were within the regulatory limits. Thus substituted bricks can be regarded as non-hazardous material.

  6. Emissions of volatile organic compounds and particulate matter from small-scale peat fire

    Science.gov (United States)

    Air pollution emitted from peat fires can negatively impact regional air quality, visibility, climate, and human health. Peat fires can smolder over long periods of time and, therefore, can release significantly greater amounts of carbon into the atmosphere per unit area compared...

  7. Emissions of volatile organic compounds and particulate matter from small-scale peat fires

    Science.gov (United States)

    Air pollution emitted from peat fires can negatively impact regional air quality, visibility, climate, and human health. Peat fires can smolder over long periods of time and, therefore, can release significantly greater amounts of carbon into the atmosphere per unit area compared...

  8. Test results of full-scale high temperature superconductors cable models destined for a 36 kV, 2 kA(rms) utility demonstration

    DEFF Research Database (Denmark)

    Daumling, M.; Rasmussen, C.N.; Hansen, F.

    2001-01-01

    with thermal terminations, an HTS cable conductor including a flexible thermal insulation, a conventional room temperature dielectric, and a closed-loop circulating cooling system maintaining the temperature between 68 and 78 K. Critical issues before the commercialisation of this technology...... are the improvement of the thermal insulation, and the reduction of costs. (C) 2001 Elsevier Science B.V. All rights reserved....

  9. Mapping wildland-urban interfaces at large scales integrating housing density and vegetation aggregation for fire prevention in the South of France

    OpenAIRE

    Lampin-Maillet, C.; Jappiot, M.; Long, M; Bouillon, C.; Morge, D.; Ferrier, J.P.

    2009-01-01

    Every year, more than 50,000 wildland fires affect about 500,000 ha of vegetation in southern European countries, particularly in wildland-urban interfaces (WUI). This paper presents a method to characterize and map WUIs at large scales and over large areas for wildland fire prevention in the South of France. Based on the combination of four types of building configuration and three classes of vegetation structure, 12 interface types were classified. Through spatial analysis, fire ignition de...

  10. Floods and Fires: Decadal-scale terrestrial data from Santa Barbara Basin during the Common Era

    Science.gov (United States)

    Heusser, L. E.; Hendy, I. L.; Pak, D. K.

    2016-12-01

    High-resolution studies of pollen and charcoal from annually-deposited laminae of Santa Barbara Basin (SBB) reflect the regional dynamics of southern coastal California vegetation from 700- to 1900 C.E. through the Medieval Climate Anomaly, the Little Ice Age to the arrival of Europeans. Kasten core SPR0901-02KC (34°16.8' N, 120°02.3' W; 588 m water depth) was analyzed for pollen at consecutive 0.5 cm depth intervals that correspond with an average deposition of five years from 150 cm to core top. During the Medieval Climate Anomaly (MCA; 800 to 1270 C.E.) SBB sediments were dominated by xeric vegetation types (drought-resistant coastal sagebrush and chaparral) implying reduced precipitation in the southern California region. Subsequent, pulsating increases in mesic arboreal vegetation, notably oak assemblages, increase from a minima at 1200 C.E., stabilizing between 1450-1550 C.E. before gradually decreasing toward the 20th century. Prior to the late 14th century, fire events (inferred from microcharcoal fragments deposited in SBB), are rare and often associated with low lithogenic input into SBB. Notable charcoal peaks normalized to pollen abundance occur at 1110, 1200, 1410-1440, 1530, and 1764, with only the 1530 event associated with a flood layer. Fires do not appear to drive significant sediment input into the basin. Increased charcoal deposition follows the settlement of California rose to peak values in the mid 19th century. Decadal-scale fluctuations in relative abundance of mesic vegetation generally correspond with variations in sea-surface temperatures inferred from foraminiferal assemblages in SBB, and are consistent with changes in northern hemisphere circulation, indicating weakened Arctic Lows and extended La Niña-like conditions during the MCA and strengthened Aleutian Lows and extended El Niño-like atmospheric conditions during the LIA. Minimal abundance of oak and pine beginning in the 18th century corresponds with the historical period in

  11. The relationship of large fire occurrence with drought and fire danger indices in the western USA, 1984-2008: The role of temporal scale

    Science.gov (United States)

    Karin L. Riley; John T. Abatzoglou; Isaac C. Grenfell; Anna E. Klene; Faith Ann Heinsch

    2013-01-01

    The relationship between large fire occurrence and drought has important implications for fire prediction under current and future climates. This study’s primary objective was to evaluate correlations between drought and fire-danger- rating indices representing short- and long-term drought, to determine which had the strongest relationships with large fire occurrence...

  12. Toxic Combustion Product Yields as a Function of Equivalence Ratio and Flame Retardants in Under-Ventilated Fires: Bench-Large-Scale Comparisons

    Directory of Open Access Journals (Sweden)

    David A. Purser

    2016-09-01

    Full Text Available In large-scale compartment fires; combustion product yields vary with combustion conditions mainly in relation to the fuel:air equivalence ratio (Φ and the effects of gas-phase flame retardants. Yields of products of inefficient combustion; including the major toxic products CO; HCN and organic irritants; increase considerably as combustion changes from well-ventilated (Φ < 1 to under-ventilated (Φ = 1–3. It is therefore essential that bench-scale toxicity tests reproduce this behaviour across the Φ range. Yield data from repeat compartment fire tests for any specific fuel show some variation on either side of a best-fit curve for CO yield as a function of Φ. In order to quantify the extent to which data from the steady state tube furnace (SSTF [1]; ISO TS19700 [2] represents compartment fire yields; the range and average deviations of SSTF data for CO yields from the compartment fire best-fit curve were compared to those for direct compartment fire measurements for six different polymeric fuels with textile and non-textile applications and for generic post-flashover fire CO yield data. The average yields; range and standard deviations of the SSTF data around the best-fit compartment fire curves were found to be close to those for the compartment fire data. It is concluded that SSTF data are as good a predictor of compartment fire yields as are repeat compartment fire test data.

  13. Cable Diagnostic Focused Initiative

    Energy Technology Data Exchange (ETDEWEB)

    Hartlein, R.A.; Hampton, R.N.

    2010-12-30

    This report summarizes an extensive effort made to understand how to effectively use the various diagnostic technologies to establish the condition of medium voltage underground cable circuits. These circuits make up an extensive portion of the electric delivery infrastructure in the United States. Much of this infrastructure is old and experiencing unacceptable failure rates. By deploying efficient diagnostic testing programs, electric utilities can replace or repair circuits that are about to fail, providing an optimal approach to improving electric system reliability. This is an intrinsically complex topic. Underground cable systems are not homogeneous. Cable circuits often contain multiple branches with different cable designs and a range of insulation materials. In addition, each insulation material ages differently as a function of time, temperature and operating environment. To complicate matters further, there are a wide variety of diagnostic technologies available for assessing the condition of cable circuits with a diversity of claims about the effectiveness of each approach. As a result, the benefits of deploying cable diagnostic testing programs have been difficult to establish, leading many utilities to avoid the their use altogether. This project was designed to help address these issues. The information provided is the result of a collaborative effort between Georgia Tech NEETRAC staff, Georgia Tech academic faculty, electric utility industry participants, as well as cable system diagnostic testing service providers and test equipment providers. Report topics include: •How cable systems age and fail, •The various technologies available for detecting potential failure sites, •The advantages and disadvantages of different diagnostic technologies, •Different approaches for utilities to employ cable system diagnostics. The primary deliverables of this project are this report, a Cable Diagnostic Handbook (a subset of this report) and an online

  14. An Analysis of Post-Fire Debris Flow Occurrence at Two Temporal Scales

    Science.gov (United States)

    Staley, D. M.; Kean, J. W.; Gartner, J. E.

    2011-12-01

    The seasonal climate, rugged topography and high relief of the Peninsular and Transverse Ranges of southern California contribute to a particularly high susceptibility to wildfire during the dry season and debris flows during the wet season. Debris flows generated in recently burned areas have repeatedly caused casualties and damaged infrastructure. With a goal of reducing the hazard to local populations, the U.S. Geological Survey has been intensively monitoring the meteorological conditions that contribute to the initiation of post-fire debris flows since 2003. Data collected in these monitoring efforts have been used to derive rainfall intensity-duration thresholds to predict the timing of debris flows. A perceived limitation of the existing thresholds is that they are temporally static, because they do not account for the influence of within-storm dynamics, seasonal rainfall, and changes in soil moisture content. Here, we attempt to develop relations between meteorological, climatic and hydrologic variables and the occurrence of debris flows with the long-term goal of developing a temporally dynamic rainfall intensity-duration threshold. We investigate the variability of debris-flow occurrence on two temporal scales. First, we compare the within-storm variability of recorded debris flow times with measures of cumulative rainfall, rainfall intensity and soil moisture content. Short-duration (≤ 30-minutes), high-intensity bursts of rainfall are tightly correlated with the recorded times of debris flows, regardless of soil moisture content or cumulative storm rainfall. Preliminary evidence suggests that debris-flow magnitude may correlate with temporally coincident local peaks of both short duration (≤ 30-minute) and longer duration (≥ 360-minute) peaks of rainfall intensity. Second, we investigate the influence of total rainfall accumulation, changes in soil moisture content, and number and average intensity of rainstorms on debris-flow occurrence during

  15. Automated Cable Preparation for Robotized Stator Cable Winding

    Directory of Open Access Journals (Sweden)

    Erik Hultman

    2017-04-01

    Full Text Available A method for robotized cable winding of the Uppsala University Wave Energy Converter generator stator has previously been presented and validated. The purpose of this study is to present and validate further developments to the method: automated stand-alone equipment for the preparation of the winding cables. The cable preparation consists of three parts: feeding the cable from a drum, forming the cable end and cutting the cable. Forming and cutting the cable was previously done manually and only small cable drums could be handled. Therefore the robot cell needed to be stopped frequently. The new equipment was tested in an experimental robot stator cable winding setup. Through the experiments, the equipment was validated to be able to perform fully automated and robust cable preparation. Suggestions are also given on how to further develop the equipment with regards to performance, robustness and quality. Hence, this work represents another important step towards demonstrating completely automated robotized stator cable winding.

  16. Multistrand superconductor cable

    Science.gov (United States)

    Borden, Albert R.

    1985-01-01

    Improved multistrand Rutherford-type superconductor cable is produced by using strands which are preformed, prior to being wound into the cable, so that each strand has a variable cross section, with successive portions having a substantially round cross section, a transitional oval cross section, a rectangular cross section, a transitional oval cross section, a round cross section and so forth, in repetitive cycles along the length of the strand. The cable is wound and flattened so that the portions of rectangular cross section extend across the two flat sides of the cable at the strand angle. The portions of round cross section are bent at the edges of the flattened cable, so as to extend between the two flat sides. The rectangular portions of the strands slide easily over one another, so as to facilitate flexing and bending of the cable, while also minimizing the possibility of causing damage to the strands by such flexing or bending. Moreover, the improved cable substantially maintains its compactness and cross-sectional shape when the cable is flexed or bent.

  17. An investigation on spill plume development and natural filling in large full-scale atrium under retail shop fire

    Energy Technology Data Exchange (ETDEWEB)

    Shi, C.L. [China Academy of Safety Sciences and Technology, State Administration of Work Safety, Beijing (China); Lu, W.Z. [City University of Hong Kong, Kowloon, Hong Kong (China). Department of Building and Construction; Chow, W.K. [The Hong Kong Polytechnic University, Hong Kong (China). Department of Building Services Engineering; Huo, R. [University of Science and Technology of China, Hefei (China). State Key Laboratory of Fire Science

    2007-02-15

    This paper reports an investigation on the scenarios of the spill plume and the resultant natural filling in a full-scale atrium mock-up due to a retail shop fire. The study includes two aspects, i.e., the full-scale experiment and the numerical simulation. A spill plume model is proposed to predict the characteristic properties of the plume development in the atrium under a retail shop fire. Furthermore, to accurately predict the shop fire in the atrium, an improved zone model is developed combining the transport lag time model and the spill plume model. Besides validating the developed model by experiments, the case is also simulated by the established zone model, i.e., CFAST code, and the computational fluid dynamics model, i.e., FDS code. By both physical and numerical experiments, the process of natural smoke filling and the temperature rise in the atrium are investigated and well understood. It is found that a typical spill plume contains three regimes, i.e., the curved section out of the retail shop door, the line plume in the near field, and the axisymmetric plume in the far field. Predictions from the proposed empirical model for the spill plume and the resultant improved zone model compare favorably with the experiments. The study indicates that the atrium becomes very dangerous due to such shop fire if no smoke control employed. The ability of mechanical exhaust system in the atrium to mitigate the hazard of a retail shop fire is investigated as well. (author)

  18. Improving Large-scale Biomass Burning Carbon Consumption and Emissions Estimates in the Former Soviet Union based on Fire Weather

    Science.gov (United States)

    Westberg, D. J.; Soja, A. J.; Tchebakova, N.; Parfenova, E. I.; Kukavskaya, E.; de Groot, B.; McRae, D.; Conard, S. G.; Stackhouse, P. W., Jr.

    2012-12-01

    Estimating the amount of biomass burned during fire events is challenging, particularly in remote and diverse regions, like those of the Former Soviet Union (FSU). Historically, we have typically assumed 25 tons of carbon per hectare (tC/ha) is emitted, however depending on the ecosystem and severity, biomass burning emissions can range from 2 to 75 tC/ha. Ecosystems in the FSU span from the tundra through the taiga to the forest-steppe, steppe and desserts and include the extensive West Siberian lowlands, permafrost-lain forests and agricultural lands. Excluding this landscape disparity results in inaccurate emissions estimates and incorrect assumptions in the transport of these emissions. In this work, we present emissions based on a hybrid ecosystem map and explicit estimates of fuel that consider the depth of burning based on the Canadian Forest Fire Weather Index System. Specifically, the ecosystem map is a fusion of satellite-based data, a detailed ecosystem map and Alexeyev and Birdsey carbon storage data, which is used to build carbon databases that include the forest overstory and understory, litter, peatlands and soil organic material for the FSU. We provide a range of potential carbon consumption estimates for low- to high-severity fires across the FSU that can be used with fire weather indices to more accurately estimate fire emissions. These data can be incorporated at ecoregion and administrative territory scales and are optimized for use in large-scale Chemical Transport Models. Additionally, paired with future climate scenarios and ecoregion cover, these carbon consumption data can be used to estimate potential emissions.

  19. The EX-SHADWELL-Full Scale Fire Research and Test Ship

    Science.gov (United States)

    1988-01-20

    Some of the areas of specific interest include detectors/sensors, fire and CPS interactions, smoke control , compartment tightness, decontami- nation...30 5.2 Fire and CPS Interaction.............................31 5 .3 Smoke Control ............i.............................31 5.4...dual threat will allow the air quality throughout the ship to be evaluated. 5.3 Smoke Control Problems associated with smoke generation and motion in

  20. Engineering model for intumescent coating behavior in a pilot-scale gas-fired furnace

    DEFF Research Database (Denmark)

    Nørgaard, Kristian Petersen; Dam-Johansen, Kim; Català, Pere

    2016-01-01

    In the event of a fire, intumescent fire protective coatings expand and form a thermally insulating char that protects the underlying substrate from heat and subsequent structural failure. The intumescence includes several rate phenomena, which have been investigated and quantified in the literat......In the event of a fire, intumescent fire protective coatings expand and form a thermally insulating char that protects the underlying substrate from heat and subsequent structural failure. The intumescence includes several rate phenomena, which have been investigated and quantified...... and adjustable model parameters for a given coating, thereby providing models for industrial applications. In this work, these two challenges are addressed. Three experimental series, with an intumescent coating inside a 0.65 m3 gas-fired furnace, heating up according to so-called cellulosic fire conditions......, were conducted and a very good repeatability was evident. The experiments were run for almost three hours, reaching a final gas temperature of about 1100 °C. Measurements include transient temperature developments inside the expanding char, at the steel substrate, and in the mineral wool insulation...

  1. Development and Testing of Industrial Scale Coal Fired Combustion System, Phase 3

    Energy Technology Data Exchange (ETDEWEB)

    Bert Zauderer

    1998-09-30

    Coal Tech Corp's mission is to develop, license & sell innovative, lowest cost, solid fuel fired power systems & total emission control processes using proprietary and patented technology for domestic and international markets. The present project 'DEVELOPMENT & TESTING OF INDUSTRIAL SCALE, COAL FIRED COMBUSTION SYSTEM, PHASE 3' on DOE Contract DE-AC22-91PC91162 was a key element in achieving this objective. The project consisted of five tasks that were divided into three phases. The first phase, 'Optimization of First Generation 20 MMBtu/hr Air-Cooled Slagging Coal Tech Combustor', consisted of three tasks, which are detailed in Appendix 'A' of this report. They were implemented in 1992 and 1993 at the first generation, 20 MMBtu/hour, combustor-boiler test site in Williamsport, PA. It consisted of substantial combustor modifications and coal-fired tests designed to improve the combustor's wall cooling, slag and ash management, automating of its operation, and correcting severe deficiencies in the coal feeding to the combustor. The need for these changes was indicated during the prior 900-hour test effort on this combustor that was conducted as part of the DOE Clean Coal Program. A combination of combustor changes, auxiliary equipment changes, sophisticated multi-dimensional combustion analysis, computer controlled automation, and series of single and double day shift tests totaling about 300 hours, either resolved these operational issues or indicated that further corrective changes were needed in the combustor design. The key result from both analyses and tests was that the combustor must be substantially lengthened to maximize combustion efficiency and sharply increase slag retention in the combustor. A measure of the success of these modifications was realized in the third phase of this project, consisting of task 5 entitled: 'Site Demonstration with the Second Generation 20 MMBtu/hr Air-Cooled Slagging Coal Tech

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

    Directory of Open Access Journals (Sweden)

    Felix Weber

    2015-01-01

    Full Text Available 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.

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

    Science.gov (United States)

    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

  4. A Landscape-Scale, Applied Fire Management Experiment Promotes Recovery of a Population of the Threatened Gouldian Finch, Erythrura gouldiae, in Australia's Tropical Savannas.

    Directory of Open Access Journals (Sweden)

    Sarah Legge

    Full Text Available Fire is an integral part of savanna ecology and changes in fire patterns are linked to biodiversity loss in savannas worldwide. In Australia, changed fire regimes are implicated in the contemporary declines of small mammals, riparian species, obligate-seeding plants and grass seed-eating birds. Translating this knowledge into management to recover threatened species has proved elusive. We report here on a landscape-scale experiment carried out by the Australian Wildlife Conservancy (AWC on Mornington Wildlife Sanctuary in northwest Australia. The experiment was designed to understand the response of a key savanna bird guild to fire, and to use that information to manage fire with the aim of recovering a threatened species population. We compared condition indices among three seed-eating bird species--one endangered (Gouldian finch and two non-threatened (long-tailed finch and double-barred finch--from two large areas (> 2,830 km2 with initial contrasting fire regimes ('extreme': frequent, extensive, intense fire; versus 'benign': less frequent, smaller, lower intensity fires. Populations of all three species living with the extreme fire regime had condition indices that differed from their counterparts living with the benign fire regime, including higher haematocrit levels in some seasons (suggesting higher levels of activity required to find food, different seasonal haematocrit profiles, higher fat scores in the early wet season (suggesting greater food uncertainty, and then lower muscle scores later in the wet season (suggesting prolonged food deprivation. Gouldian finches also showed seasonally increasing stress hormone concentrations with the extreme fire regime. Cumulatively, these patterns indicated greater nutritional stress over many months for seed-eating birds exposed to extreme fire regimes. We tested these relationships by monitoring finch condition over the following years, as AWC implemented fire management to produce the 'benign

  5. A Landscape-Scale, Applied Fire Management Experiment Promotes Recovery of a Population of the Threatened Gouldian Finch, Erythrura gouldiae, in Australia’s Tropical Savannas

    Science.gov (United States)

    Legge, Sarah; Garnett, Stephen; Maute, Kim; Heathcote, Joanne; Murphy, Steve; Woinarski, John C. Z.; Astheimer, Lee

    2015-01-01

    Fire is an integral part of savanna ecology and changes in fire patterns are linked to biodiversity loss in savannas worldwide. In Australia, changed fire regimes are implicated in the contemporary declines of small mammals, riparian species, obligate-seeding plants and grass seed-eating birds. Translating this knowledge into management to recover threatened species has proved elusive. We report here on a landscape-scale experiment carried out by the Australian Wildlife Conservancy (AWC) on Mornington Wildlife Sanctuary in northwest Australia. The experiment was designed to understand the response of a key savanna bird guild to fire, and to use that information to manage fire with the aim of recovering a threatened species population. We compared condition indices among three seed-eating bird species–one endangered (Gouldian finch) and two non-threatened (long-tailed finch and double-barred finch)—from two large areas (> 2,830 km2) with initial contrasting fire regimes (‘extreme’: frequent, extensive, intense fire; versus ‘benign’: less frequent, smaller, lower intensity fires). Populations of all three species living with the extreme fire regime had condition indices that differed from their counterparts living with the benign fire regime, including higher haematocrit levels in some seasons (suggesting higher levels of activity required to find food), different seasonal haematocrit profiles, higher fat scores in the early wet season (suggesting greater food uncertainty), and then lower muscle scores later in the wet season (suggesting prolonged food deprivation). Gouldian finches also showed seasonally increasing stress hormone concentrations with the extreme fire regime. Cumulatively, these patterns indicated greater nutritional stress over many months for seed-eating birds exposed to extreme fire regimes. We tested these relationships by monitoring finch condition over the following years, as AWC implemented fire management to produce the

  6. Mapping wildland fuels for fire management across multiple scales: integrating remote sensing, GIS, and biophysical modeling

    Science.gov (United States)

    Keane, Robert E.; Burgan, Robert E.; Van Wagtendonk, Jan W.

    2001-01-01

    Fuel maps are essential for computing spatial fire hazard and risk and simulating fire growth and intensity across a landscape. However, fuel mapping is an extremely difficult and complex process requiring expertise in remotely sensed image classification, fire behavior, fuels modeling, ecology, and geographical information systems (GIS). This paper first presents the challenges of mapping fuels: canopy concealment, fuelbed complexity, fuel type diversity, fuel variability, and fuel model generalization. Then, four approaches to mapping fuels are discussed with examples provided from the literature: (1) field reconnaissance; (2) direct mapping methods; (3) indirect mapping methods; and (4) gradient modeling. A fuel mapping method is proposed that uses current remote sensing and image processing technology. Future fuel mapping needs are also discussed which include better field data and fuel models, accurate GIS reference layers, improved satellite imagery, and comprehensive ecosystem models.

  7. Development and testing of commercial-scale, coal-fired combustion systems: Phase III. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Based on studies that indicated a large potential for significantly increased coal-firing in the commercial sector, the U.S. Department of Energy`s Pittsburgh Energy Technology Center (PETC) sponsored a multi-phase development effort for advanced coal combustion systems. This Final Report presents the results of the last phase (Phase III) of a project for the development of an advanced coal-fired system for the commercial sector of the economy. The project performance goals for the system included dual-fuel capability (i.e., coal as primary fuel and natural gas as secondary fuel), combustion efficiency exceeding 99 percent, thermal efficiency greater than 80 percent, turndown of at least 3:1, dust-free and semi-automatic dry ash removal, fully automatic start-up with system purge and ignition verification, emissions performance exceeding New Source Performance Standards (NSPS) and approaching those produced by oil-fired, Commercial-sized units, and reliability, safety, operability, maintainability, and service life comparable to oil-fired units. The program also involved a site demonstration at a large facility owned by Striegel Supply Company, a portion of which was leased to MTCI. The site, mostly warehouse space, was completely unheated and the advanced coal-fired combustion system was designed and sized to heat this space. Three different coals were used in the project, one low and one high sulfur pulverized Pittsburgh No. 8 coal, and a micronized low volatile, bituminous coal. The sorbents used were Pfizer dolomitic limestone and an Anvil lime. More than 100 hours of screening test`s were performed to characterize the system. The parameters examined included coal firing rate, excess air level, ash recycle rate, coal type, dolomitic limestone feed rate, and steam injection rate. These tests indicated that some additional modifications for coal burning in the system were required.

  8. Fire Resistance of Large-Scale Cross-Laminated Timber Panels

    Science.gov (United States)

    Henek, Vladan; Venkrbec, Václav; Novotný, Miloslav

    2017-12-01

    Wooden structures are increasingly being used in the construction of residential buildings. A common and often published reason to avoid wooden structures is their insufficient fire resistance, which reduces bearing capacity. For this reason, composite sandwich structures began to be designed to eliminate this drawback, as well as others. Recently, however, the trend is for a return to the original, wood-only variant and a search is underway for new technical means of improving the properties of such structures. Many timber structure technologies are known, but structures made from cross-laminated timber (CLT) panels have been used very often in recent years. CLT panels, also known as X-LAM, are currently gaining popularity in Europe. In the case of CLT panels composed of several layers of boards, they can be said to offer a certain advantage in that after the surface layer of a board has burnt and the subsurface layer has dried, oxygen is not drawn to the unburned wood for further combustion and thus the burning process ceases. CLT panels do not need to be specially modified or coated with fire resistant materials, although they are usually lined with gypsum-fibre fire resistant boards due to guidelines set out in the relevant standards. This paper presents a new method for the assessment of load-bearing perimeter walls fabricated from CLT panels without the use of an inner fire-retardant lining to ensure fire resistance at the level required by European standards (i.e. those harmonized for the Czech construction industry). The calculations were verified through laboratory tests which show that better parameters can be achieved during the classification of structures from the fire resistance point of view. The aim of the article is to utilize the results of assessment and testing by an accredited laboratory in order to demonstrate the possibilities of using CLT panels for the construction of multistorey as well as multi-purpose buildings in the Czech Republic.

  9. Fatigue of cable anchorage of large cable stayed bridge; Daikibo shachokyo cable teichaku kozo no hiro

    Energy Technology Data Exchange (ETDEWEB)

    Endo, T.; Matsumoto, T. [Honshu-Shikoku Bridge Authority, Tokyo (Japan); Tsukahara, H. [Yokogawa Bridge Corp., Tokyo (Japan); Miki, C. [Tokyo Institute of Technology, Tokyo (Japan)

    1995-10-21

    Design considerations such as design schemes, the assemblage and welding of steel plates, and safety for fatigue of welded connections have to be taken for the cable anchorages of the steel cable stayed bridges. In this study, two full scale models, which have different shape of box anchorages welded to the web of the main girder, were made to investigate fatigue characteristics as well as assemblage of plate and gelding details. Finite element analyses for both test models and actual bridges here carried out to compare stress distribution. It was confirmed that the assemblage and welding of both types of box anchorage were attainable kith required quality and accuracy. According to the fatigue test, fatigue cracks originated from the weldings of the bearing plate to which the load from cable socket applied directly were caused by out-of-plane bending of the bearing plate. It was proved that the slight modifications of the details around the bearing plate resulted in sufficient fatigue strength in both types of anchorage. 1 ref., 23 figs., 2 tabs.

  10. Robotic Arm Biobarrier Cable

    Science.gov (United States)

    2008-01-01

    This image, taken by the Surface Stereo Imager on NASA's Phoenix Mars Lander on the 14th Martian day of the mission (June 7, 2008), shows the cable that held the Robotic Arm's biobarrier in place during flight has snapped. The cable's springs retracted to release the biobarrier right after landing. To the lower right of the image a spring is visible. Extending from that spring is a length of cable that snapped during the biobarrier's release. A second spring separated from the cable when it snapped and has been photographed on the ground under the lander near one of the legs. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  11. Using a stochastic model and cross-scale analysis to evaluate controls on historical low-severity fire regimes

    Science.gov (United States)

    Maureen C. Kennedy; Donald. McKenzie

    2010-01-01

    Fire-scarred trees provide a deep temporal record of historical fire activity, but identifying the mechanisms therein that controlled landscape fire patterns is not straightforward. We use a spatially correlated metric for fire co-occurrence between pairs of trees (the Sørensen distance variogram), with output from a neutral model for fire history, to infer the...

  12. Continental-scale simulation of burn probabilities, flame lengths, and fire size distribution for the United States

    Science.gov (United States)

    Mark A. Finney; Charles W. McHugh; Isaac Grenfell; Karin L. Riley

    2010-01-01

    Components of a quantitative risk assessment were produced by simulation of burn probabilities and fire behavior variation for 134 fire planning units (FPUs) across the continental U.S. The system uses fire growth simulation of ignitions modeled from relationships between large fire occurrence and the fire danger index Energy Release Component (ERC). Simulations of 10,...

  13. Monitoring and assessment of soil erosion at micro-scale and macro-scale in forests affected by fire damage in northern Iran.

    Science.gov (United States)

    Akbarzadeh, Ali; Ghorbani-Dashtaki, Shoja; Naderi-Khorasgani, Mehdi; Kerry, Ruth; Taghizadeh-Mehrjardi, Ruhollah

    2016-12-01

    Understanding the occurrence of erosion processes at large scales is very difficult without studying them at small scales. In this study, soil erosion parameters were investigated at micro-scale and macro-scale in forests in northern Iran. Surface erosion and some vegetation attributes were measured at the watershed scale in 30 parcels of land which were separated into 15 fire-affected (burned) forests and 15 original (unburned) forests adjacent to the burned sites. The soil erodibility factor and splash erosion were also determined at the micro-plot scale within each burned and unburned site. Furthermore, soil sampling and infiltration studies were carried out at 80 other sites, as well as the 30 burned and unburned sites, (a total of 110 points) to create a map of the soil erodibility factor at the regional scale. Maps of topography, rainfall, and cover-management were also determined for the study area. The maps of erosion risk and erosion risk potential were finally prepared for the study area using the Revised Universal Soil Loss Equation (RUSLE) procedure. Results indicated that destruction of the protective cover of forested areas by fire had significant effects on splash erosion and the soil erodibility factor at the micro-plot scale and also on surface erosion, erosion risk, and erosion risk potential at the watershed scale. Moreover, the results showed that correlation coefficients between different variables at the micro-plot and watershed scales were positive and significant. Finally, assessment and monitoring of the erosion maps at the regional scale showed that the central and western parts of the study area were more susceptible to erosion compared with the western regions due to more intense crop-management, greater soil erodibility, and more rainfall. The relationships between erosion parameters and the most important vegetation attributes were also used to provide models with equations that were specific to the study region. The results of this

  14. Short- term effects of post-fire logging on runoff and soil erosion at two spatial scales

    Science.gov (United States)

    Malvar, Maruxa; Silva, Flavio; Prats, Sergio; Vieira, Diana; Keizer, Jacob

    2017-04-01

    Logging is the most common management practice after wildfires in forested areas in Portugal. Clearcutting is undertaken to recover burnt timber resources, to control resprouting, notably in the case of eucalypt plantations, and to reduce the risks of possible insect plagues, notably in the case of maritime pine because of the nematode plague. Still, relatively little is known about the combined effect of wildfire and post-fire logging on erosion processes. In the framework of the EU-FP7 project RECARE (www.recare-project.eu), the ESP team of the University of Aveiro set up an experiment to quantify the hydrological and erosion impacts of post-fire logging, at the scale of both 0.25 m2 micro-plots and 16 m2 plots. A eucalypt slope burnt in August 2015 by a moderate intensity fire and logged in September 2015 was selected for this study. The burned trees were harvested with a chainsaw, while the logs were piled with a rubber wheeled forwarder tractor. Following logging, two distinct sub-areas were identified within the logged slope based on soil disturbance: an area where the forwarder wheels had left marked trails ("trail"), and an area where such trails were absent ("control"). Three micro-plots and three plots were installed in the control area, while three micro-plots and six plots were installed in the trail area. Generally, the trail area showed greater soil compaction and larger soil surface roughness than the control area. Between October 2015 and September 2016, mean runoff was 500 mm in the control micro-plots and 50% higher in the trail micro-plots. At the plot scale, however, no differences in runoff generation were observed between the two subareas. Sediment production over the same period, however, was twice as high in the trail area than the control area, at both plot scales. In the control area, mean sediment production was 8 Mg ha-1 yr-1 at the micro-plot scale and 6 Mg ha-1 yr-1at the plot scale; in the trail area, these figures were 21 Mg ha-1 yr

  15. GREENHOUSE GAS EMISSIONS CONTROL BY OXYGEN FIRING IN CIRCULATING FLUIDIZED BED BOILERS: PHASE II--PILOT SCALE TESTING AND UPDATED PERFORMANCE AND ECONOMICS FOR OXYGEN FIRED CFB WITH CO2 CAPTURE

    Energy Technology Data Exchange (ETDEWEB)

    Nsakala ya Nsakala; Gregory N. Liljedahl; David G. Turek

    2004-10-27

    Because fossil fuel fired power plants are among the largest and most concentrated producers of CO{sub 2} emissions, recovery and sequestration of CO{sub 2} from the flue gas of such plants has been identified as one of the primary means for reducing anthropogenic CO{sub 2} emissions. In this Phase II study, ALSTOM Power Inc. (ALSTOM) has investigated one promising near-term coal fired power plant configuration designed to capture CO{sub 2} from effluent gas streams for sequestration. Burning fossil fuels in mixtures of oxygen and recirculated flue gas (made principally of CO{sub 2}) essentially eliminates the presence of atmospheric nitrogen in the flue gas. The resulting flue gas is comprised primarily of CO{sub 2}, along with some moisture, nitrogen, oxygen, and trace gases like SO{sub 2} and NO{sub x}. Oxygen firing in utility scale Pulverized Coal (PC) fired boilers has been shown to be a more economical method for CO{sub 2} capture than amine scrubbing (Bozzuto, et al., 2001). Additionally, oxygen firing in Circulating Fluid Bed Boilers (CFB's) can be more economical than in PC or Stoker firing, because recirculated gas flow can be reduced significantly. Oxygen-fired PC and Stoker units require large quantities of recirculated flue gas to maintain acceptable furnace temperatures. Oxygen-fired CFB units, on the other hand, can accomplish this by additional cooling of recirculated solids. The reduced recirculated gas flow with CFB plants results in significant Boiler Island cost savings resulting from reduced component The overall objective of the Phase II workscope, which is the subject of this report, is to generate a refined technical and economic evaluation of the Oxygen fired CFB case (Case-2 from Phase I) utilizing the information learned from pilot-scale testing of this concept. The objective of the pilot-scale testing was to generate detailed technical data needed to establish advanced CFB design requirements and performance when firing coals and

  16. Variance in population firing rate as a measure of slow time-scale correlation

    Directory of Open Access Journals (Sweden)

    Adam C. Snyder

    2013-12-01

    Full Text Available Correlated variability in the spiking responses of pairs of neurons, also known as spike count correlation, is a key indicator of functional connectivity and a critical factor in population coding. Underscoring the importance of correlation as a measure for cognitive neuroscience research is the observation that spike count correlations are not fixed, but are rather modulated by perceptual and cognitive context. Yet while this context fluctuates from moment to moment, correlation must be calculated over multiple trials. This property undermines its utility as a dependent measure for investigations of cognitive processes which fluctuate on a trial-to-trial basis, such as selective attention. A measure of functional connectivity that can be assayed on a moment-to-moment basis is needed to investigate the single-trial dynamics of populations of spiking neurons. Here, we introduce the measure of population variance in normalized firing rate for this goal. We show using mathematical analysis, computer simulations and in vivo data how population variance in normalized firing rate is inversely related to the latent correlation in the population, and how this measure can be used to reliably classify trials from different typical correlation conditions, even when firing rate is held constant. We discuss the potential advantages for using population variance in normalized firing rate as a dependent measure for both basic and applied neuroscience research.

  17. Alkali chloride induced corrosion of superheaters under biomass firing conditions: Improved insights from laboratory scale studies

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Montgomery, Melanie; Jappe Frandsen, Flemming

    2015-01-01

    One of the major operational challenges experienced by power plants firing biomass is the high corrosion rate of superheaters. This limits the outlet steam temperature of the superheaters and consequently, the efficiency of the power plants. The high corrosion rates have been attributed...... to the formation of corrosive deposits (rich in alkali chlorides) on the surfaces of the superheaters. Accordingly, an extensive number of fundamental investigations have been undertaken to understand the basic mechanisms behind the alkali chloride induced high temperature corrosion of superheaters (for example......, [1–3]). However, complete understanding of the corrosion mechanism under biomass-firing conditions has not yet been achieved. This is attributed partly to the complex nature of the corrosion process since there are many species produced from fuel combustion which can interact with one another...

  18. Sixty-four-Channel Inline Cable Tester

    Science.gov (United States)

    2008-01-01

    Faults in wiring are a serious concern for the aerospace and aeronautics (commercial, military, and civil) industries. A number of accidents have occurred because faulty wiring created shorts or opens that resulted in the loss of control of the aircraft or because arcing led to fires and explosions. Some of these accidents have resulted in the massive loss of lives (such as in the TWA Flight 800 accident). Circuits on the Space Shuttle have also failed because of faulty insulation on wiring. STS-93 lost power when a primary power circuit in one engine failed and a second engine had a backup power circuit fault. Cables are usually tested on the ground after the crew reports a fault encountered during flight. Often such failures result from vibration and cannot be replicated while the aircraft is stationary. It is therefore important to monitor faults while the aircraft is in operation, when cables are more likely to fail. Work is in progress to develop a cable fault tester capable of monitoring up to 64 individual wires simultaneously. Faults can be monitored either inline or offline. In the inline mode of operation, the monitoring is performed without disturbing the normal operation of the wires under test. That is, the operations are performed unintrusively and are essentially undetectable for the test signal levels are below the noise floor. A cable can be monitored several times per second in the offline mode and once a second in the inline mode. The 64-channel inline cable tester not only detects the occurrence of a fault, but also determines the type of fault (short/open) and the location of the fault. This will enable the detection of intermittent faults that can be repaired before they become serious problems.

  19. Using fine-scale fuel measurements to assess wildland fuels, potential fire behavior and hazard mitigation treatments in the southeastern USA

    Science.gov (United States)

    Roger D. Ottmar; John I. Blake; William T. Crolly

    2012-01-01

    The inherent spatial and temporal heterogeneity of fuel beds in forests of the southeastern United States may require fine scale fuel measurements for providing reliable fire hazard and fuel treatment effectiveness estimates. In a series of five papers, an intensive, fine scale fuel inventory from the Savanna River Site in the southeastern United States is used for...

  20. Shape accuracy optimization for cable-rib tension deployable antenna structure with tensioned cables

    Science.gov (United States)

    Liu, Ruiwei; Guo, Hongwei; Liu, Rongqiang; Wang, Hongxiang; Tang, Dewei; Song, Xiaoke

    2017-11-01

    Shape accuracy is of substantial importance in deployable structures as the demand for large-scale deployable structures in various fields, especially in aerospace engineering, increases. The main purpose of this paper is to present a shape accuracy optimization method to find the optimal pretensions for the desired shape of cable-rib tension deployable antenna structure with tensioned cables. First, an analysis model of the deployable structure is established by using finite element method. In this model, geometrical nonlinearity is considered for the cable element and beam element. Flexible deformations of the deployable structure under the action of cable network and tensioned cables are subsequently analyzed separately. Moreover, the influence of pretension of tensioned cables on natural frequencies is studied. Based on the results, a genetic algorithm is used to find a set of reasonable pretension and thus minimize structural deformation under the first natural frequency constraint. Finally, numerical simulations are presented to analyze the deployable structure under two kinds of constraints. Results show that the shape accuracy and natural frequencies of deployable structure can be effectively improved by pretension optimization.

  1. Fireset and Cable Design for Support of Detonator Diagnostic Development

    Science.gov (United States)

    Trujillo, Christopher; Francois, Elizabeth; Gibson, John; Lodes, Rylie; Nakamoto, Teagan; Smith, Dalton; Tasker, Douglas; Parrack, Kristina; Wilde, Zakary

    2017-06-01

    The performance of detonators can be affected by porosity effects in high explosive (HE) materials. In an effort to understand how these effects characterize performance, experiments are to be performed implementing new approaches with advanced diagnostics. This presentation will include the design choices and implementation of diagnostics within two primary components in the experimental test set up, the fire-set and cables. The fire-set contains a current viewing resistor (CVR) which characterizes the electrical performance of the detonator. The cable between the fire-set and detonator includes a Rogowski coil to measure the induced current passing to the detonator. We will present the experimental results and discuss the relevance of these data in the context of the overall experiments.

  2. VT Cable Modem Systems 2013

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The VT Cable Modem dataset (CABLEMOD2013) includes lines depicting the extent of Vermont's cable modem broadband system as of 6/30/2013. This data...

  3. VT Cable Modem Systems 2007

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The VT Cable Modem dataset (CABLEMOD2007) includes lines depicting the extent of Vermont's cable modem broadband system as of 12/31/2007. This...

  4. VT Cable Modem Systems 2005

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The VT Cable Modem dataset (CABLEMOD2005) includes lines depicting the extent of Vermont's cable modem broadband system as of 12/31/2005. This...

  5. Logistics, Costs, and GHG Impacts of Utility-Scale Co-Firing with 20% Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Nichol, Corrie Ian [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2013-06-01

    This study analyzes the possibility that biopower in the U.S. is a cost-competitive option to significantly reduce greenhouse gas emissions. In 2009, net greenhouse gas (GHG) emitted in the United States was equivalent to 5,618 million metric tons CO2, up 5.6% from 1990 (EPA 2011). Coal-fired power generation accounted for 1,748 million metric tons of this total. Intuitively, life-cycle CO2 emissions in the power sector could be reduced by substituting renewable biomass for coal. If just 20% of the coal combusted in 2009 had been replaced with biomass, CO2 emissions would have been reduced by 350 million metric tons, or about 6% of net annual GHG emission. This would have required approximately 225 million tons of dry biomass. Such an ambitious fuel substitution would require development of a biomass feedstock production and supply system tantamount to coal. This material would need to meet stringent specifications to ensure reliable conveyance to boiler burners, efficient combustion, and no adverse impact on heat transfer surfaces and flue gas cleanup operations. Therefore, this report addresses the potential cost/benefit tradeoffs of co-firing 20% specification-qualified biomass (on an energy content basis) in large U.S. coal-fired power plants. The dependence and sensitivity of feedstock cost on source of material, location, supply distance, and demand pressure was established. Subsequently, the dependence of levelized cost of electricity (LCOE) on feedstock costs, power plant feed system retrofit, and impact on boiler performance was determined. Overall life-cycle assessment (LCA) of greenhouse gas emissions saving were next evaluated and compared to wind and solar energy to benchmark the leading alternatives for meeting renewable portfolio standards (or RPS).

  6. Economical Aspects of Superconducting Cable

    Science.gov (United States)

    Ohya, Masayoshi

    High-temperature superconducting (HTS) cables are expected to resolve technical problems with power grids because they put large-capacity, low-loss power transmission into a compact package. One problem is replacing old 275-kV oil filled (OF) cables with cross-linked polyethylene insulated vinyl sheath cables (XLPE cables). This is difficult because XLPE cable has a lower transmission capacity than OF cable. In addition, the high concentration of public infrastructure underground makes it extremely difficult to build new ones. However, if 66-kV HTS cables can be installed inside existing underground conduits and can achieve a power capacity equivalent to conventional 275-kV cables, construction costs could be significantly reduced. Moreover, if XLPE cables are used for a 1,000 MVA-class transmission line, then three circuits of nine 275-kV single-core cables would be required, which would incur a transmission loss of 90 W/m/cct. Three circuits of three 66-kV Three-in-One HTS cables, however, with an AC loss of 1 W/m/ph@3 kA, heat invasion of 2 W/m, and cooling system efficiency of 0.1, would reduce transmission loss to less than three-fifths that of XLPE cables.

  7. High Temperature Superconducting Underground Cable

    Energy Technology Data Exchange (ETDEWEB)

    Farrell, Roger, A.

    2010-02-28

    The purpose of this Project was to design, build, install and demonstrate the technical feasibility of an underground high temperature superconducting (HTS) power cable installed between two utility substations. In the first phase two HTS cables, 320 m and 30 m in length, were constructed using 1st generation BSCCO wire. The two 34.5 kV, 800 Arms, 48 MVA sections were connected together using a superconducting joint in an underground vault. In the second phase the 30 m BSCCO cable was replaced by one constructed with 2nd generation YBCO wire. 2nd generation wire is needed for commercialization because of inherent cost and performance benefits. Primary objectives of the Project were to build and operate an HTS cable system which demonstrates significant progress towards commercial progress and addresses real world utility concerns such as installation, maintenance, reliability and compatibility with the existing grid. Four key technical areas addressed were the HTS cable and terminations (where the cable connects to the grid), cryogenic refrigeration system, underground cable-to-cable joint (needed for replacement of cable sections) and cost-effective 2nd generation HTS wire. This was the world’s first installation and operation of an HTS cable underground, between two utility substations as well as the first to demonstrate a cable-to-cable joint, remote monitoring system and 2nd generation HTS.

  8. The Danish Superconducting Cable Project

    DEFF Research Database (Denmark)

    Tønnesen, Ole

    1997-01-01

    The design and construction of a superconducting cable is described. The cable has a room temperature dielectric design with the cryostat placed inside the electrical insulation.BSCCO 2223 superconducting tapes wound in helix form around a former are used as the cable conductor. Results from...

  9. Development and test of small-scale batch-fired straw boilers in Denmark

    Energy Technology Data Exchange (ETDEWEB)

    Kristensen, E.F.; Kristensen, J.K. [Danish Institute of Agricultural Sciences, Horsens (Denmark). Dept. of Agricultural Engineering

    2004-06-01

    In Denmark, government subsidies for the testing and installation of biomass-fired boilers were available for the period from 1995 until 2002. Each boiler type had to pass an official approval test to achieve subsidy. The combustion abilities of the boiler were optimized prior to the test. The main aim of this subsidy was to encourage the development of energy-efficient and environmentally friendly boilers. The scheme was therefore organized in such a way that the greatest subsidies were awarded for boilers with high efficiency and low emissions. This goal has in effect been achieved for batch-fired straw boilers, where the typical efficiency has been increased from about 75% in 1995 to about 87% in 2002. Similarly, the carbon monoxide emissions have been reduced from 5000 ppm (reference value 10% O{sub 2}) in 1995 to less than 1000 ppm in 2002. These improvements are mainly due to better insulation inside the combustion chamber, more efficient techniques for supplying air to the combustion process, improved cooling of the flue gas, and optimization of the electronic control unit for the air supply. (author)

  10. Simulations of microphysical, radiative, and dynamical processes in a continental-scale forest fire smoke plume

    Science.gov (United States)

    Westphal, Douglas L.; Toon, Owen B.

    1991-01-01

    The impact of a large forest fire smoke plume on atmospheric processes is studied through a numerical model of meteorology, aerosols, and radiative transfer. The simulated smoke optical depths at 0.63-micron wavelength are in agreement with analyses of satellite data and show values as high as 1.8. The smoke has an albedo of 35 percent, or more than double the clear-sky value, and cools the surface by as much as 5 K. An imaginary refractive index, n sub im, of 0.01 yields results which closely match the observed cooling, single scattering albedo, and the Angstrom wavelength exponent. An n exp im of 0.1, typical of smoke from urban fires, produces 9 K cooling. Coagulation causes the geometric mean radius by number to increase from the initial value of 0.08 micron to a final value of 0.15 micron, while the specific extinction and absorption increase by 40 and 25 percent, respectively.

  11. The Coaxial Cable

    Indian Academy of Sciences (India)

    metal pipe you see direct proof that electromagnetic energy does propagate through a tube. Light is an electromagnetic wave! Then why do cable TV operators put in an inner wire? To find the answer, we need to write down all the relevant equations and solve them. This looks like a problem in calculus, but, as you will see, ...

  12. Exceptional Cable Television.

    Science.gov (United States)

    Hunt, Edmund B.; Reid, John E., Jr.

    1987-01-01

    Ways in which the resources of a university's special education, communication arts, and library services can be combined with those of special education consortiums or parent organizations to provide exceptional children and their parents and teachers with high-quality cable educational television programs that meet their varied needs are…

  13. PILOT-AND FULL-SCALE DEMONSTRATION OF ADVANCED MERCURY CONTROL TECHNOLOGIES FOR LIGNITE-FIRED POWER PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Steven A. Benson; Charlene R. Crocker; Kevin C. Galbreath; Jay R. Gunderson; Michael J. Holmes; Jason D. Laumb; Jill M. Mackenzie; Michelle R. Olderbak; John H. Pavlish; Li Yan; Ye Zhuang

    2005-02-01

    The overall objective of the project was to develop advanced innovative mercury control technologies to reduce mercury emissions by 50%-90% in flue gases typically found in North Dakota lignite-fired power plants at costs from one-half to three-quarters of current estimated costs. Power plants firing North Dakota lignite produce flue gases that contain >85% elemental mercury, which is difficult to collect. The specific objectives were focused on determining the feasibility of the following technologies: Hg oxidation for increased Hg capture in dry scrubbers, incorporation of additives and technologies that enhance Hg sorbent effectiveness in electrostatic precipitators (ESPs) and baghouses, the use of amended silicates in lignite-derived flue gases for Hg capture, and the use of Hg adsorbents within a baghouse. The approach to developing Hg control technologies for North Dakota lignites involved examining the feasibility of the following technologies: Hg capture upstream of an ESP using sorbent enhancement, Hg oxidation and control using dry scrubbers, enhanced oxidation at a full-scale power plant using tire-derived fuel and oxidizing catalysts, and testing of Hg control technologies in the Advanced Hybrid{trademark} filter.

  14. Mapping wildland-urban interfaces at large scales integrating housing density and vegetation aggregation for fire prevention in the South of France.

    Science.gov (United States)

    Lampin-Maillet, Corinne; Jappiot, Marielle; Long, Marlène; Bouillon, Christophe; Morge, Denis; Ferrier, Jean-Paul

    2010-01-01

    Every year, more than 50,000 wildland fires affect about 500,000ha of vegetation in southern European countries, particularly in wildland-urban interfaces (WUI). This paper presents a method to characterize and map WUIs at large scales and over large areas for wildland fire prevention in the South of France. Based on the combination of four types of building configuration and three classes of vegetation structure, 12 interface types were classified. Through spatial analysis, fire ignition density and burned area ratio were linked with the different types of WUI. Among WUI types, isolated WUIs with the lowest housing density represent the highest level of fire risk. 2009 Elsevier Ltd. All rights reserved.

  15. Selection of fire-created snags at two spatial scales by cavity-nesting birds

    Science.gov (United States)

    Victoria A. Saab; Ree Brannon; Jonathan Dudley; Larry Donohoo; Dave Vanderzanden; Vicky Johnson; Henry Lachowski

    2002-01-01

    We examined the use of snag stands by seven species of cavity-nesting birds from 1994-1998. Selection of snags was studied in logged and unlogged burned forests at two spatial scales: microhabitat (local vegetation characteristics) and landscape (composition and patterning of surrounding vegetation types). We modeled nest occurrence at the landscape scale by using...

  16. Development of inspection robots for bridge cables.

    Science.gov (United States)

    Yun, Hae-Bum; Kim, Se-Hoon; Wu, Liuliu; Lee, Jong-Jae

    2013-01-01

    This paper presents the bridge cable inspection robot developed in Korea. Two types of the cable inspection robots were developed for cable-suspension bridges and cable-stayed bridge. The design of the robot system and performance of the NDT techniques associated with the cable inspection robot are discussed. A review on recent advances in emerging robot-based inspection technologies for bridge cables and current bridge cable inspection methods is also presented.

  17. Development of Inspection Robots for Bridge Cables

    Directory of Open Access Journals (Sweden)

    Hae-Bum Yun

    2013-01-01

    Full Text Available This paper presents the bridge cable inspection robot developed in Korea. Two types of the cable inspection robots were developed for cable-suspension bridges and cable-stayed bridge. The design of the robot system and performance of the NDT techniques associated with the cable inspection robot are discussed. A review on recent advances in emerging robot-based inspection technologies for bridge cables and current bridge cable inspection methods is also presented.

  18. LARGE-SCALE MECURY CONTROL TECHNOLOGY TESTING FOR LIGNITE-FIRED UTILITIES-OXIDATION SYSTEMS FOR WET FGD

    Energy Technology Data Exchange (ETDEWEB)

    Michael J. Holmes; Steven A. Benson; Jeffrey S. Thompson

    2004-03-01

    The Energy & Environmental Research Center (EERC) is conducting a consortium-based effort directed toward resolving the mercury (Hg) control issues facing the lignite industry. Specifically, the EERC team--the EERC, EPRI, URS, ADA-ES, Babcock & Wilcox, the North Dakota Industrial Commission, SaskPower, and the Mercury Task Force, which includes Basin Electric Power Cooperative, Otter Tail Power Company, Great River Energy, Texas Utilities (TXU), Montana-Dakota Utilities Co., Minnkota Power Cooperative, BNI Coal Ltd., Dakota Westmoreland Corporation, and the North American Coal Company--has undertaken a project to significantly and cost-effectively oxidize elemental mercury in lignite combustion gases, followed by capture in a wet scrubber. This approach will be applicable to virtually every lignite utility in the United States and Canada and potentially impact subbituminous utilities. The oxidation process is proven at the pilot-scale and in short-term full-scale tests. Additional optimization is continuing on oxidation technologies, and this project focuses on longer-term full-scale testing. The lignite industry has been proactive in advancing the understanding of and identifying control options for Hg in lignite combustion flue gases. Approximately 1 year ago, the EERC and EPRI began a series of Hg-related discussions with the Mercury Task Force as well as utilities firing Texas and Saskatchewan lignites. This project is one of three being undertaken by the consortium to perform large-scale Hg control technology testing to address the specific needs and challenges to be met in controlling Hg from lignite-fired power plants. This project involves Hg oxidation upstream of a system equipped with an electrostatic precipitator (ESP) followed by wet flue gas desulfurization (FGD). The team involved in conducting the technical aspects of the project includes the EERC, Babcock & Wilcox, URS, and ADA-ES. The host sites include Minnkota Power Cooperative Milton R. Young

  19. Fire-protection research for energy technology: FY 80 year-end report. [For fusion energy experiments and other energy research

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, H.K.; Alvares, N.J.; Lipska, A.E.; Ford, H.; Priante, S.; Beason, D.G.

    1981-05-26

    This continuing research program was initiated in 1977 in order to advance fire protection strategies for Fusion Energy Experiments (FEE). The program has since been expanded to encompass other forms of energy research. Accomplishments for fiscal year 1980 were: finalization of the fault-tree analysis of the Shiva fire management system; development of a second-generation, fire-growth analysis using an alternate moel and new LLNL combustion dynamics data; improvements of techniques for chemical smoke aerosol analysis; development and test of a simple method to assess the corrosive potential of smoke aerosols; development of an initial aerosol dilution system; completion of primary small-scale tests for measurements of the dynamics of cable fires; finalization of primary survey format for non-LLNL energy technology facilities; and studies of fire dynamics and aerosol production from electrical insulation and computer tape cassettes.

  20. Method to improve superconductor cable

    Science.gov (United States)

    Borden, A.R.

    1984-03-08

    A method is disclosed of making a stranded superconductor cable having improved flexing and bending characteristics. In such method, a plurality of superconductor strands are helically wound around a cylindrical portion of a mandrel which tapers along a transitional portion to a flat end portion. The helically wound strands form a multistrand hollow cable which is partially flattened by pressure rollers as the cable travels along the transitional portion. The partially flattened cable is impacted with repeated hammer blows as the hollow cable travels along the flat end portion. The hammer blows flatten both the internal and the external surfaces of the strands. The cable is fully flattened and compacted by two sets of pressure rollers which engage the flat sides and the edges of the cable after it has traveled away from the flat end portion of the mandrel. The flattened internal surfaces slide easily over one another when the cable is flexed or bent so that there is very little possibility that the cable will be damaged by the necessary flexing and bending required to wind the cable into magnet coils.

  1. Jointly optimizing selection of fuel treatments and siting of forest biomass-based energy production facilities for landscape-scale fire hazard reduction.

    Science.gov (United States)

    Peter J. Daugherty; Jeremy S. Fried

    2007-01-01

    Landscape-scale fuel treatments for forest fire hazard reduction potentially produce large quantities of material suitable for biomass energy production. The analytic framework FIA BioSum addresses this situation by developing detailed data on forest conditions and production under alternative fuel treatment prescriptions, and computes haul costs to alternative sites...

  2. Climate-vegetation-fire linkages on decadal-to-millennial time scales along the Patagonian forest-steppe ecotone (41 - 43°S)

    Science.gov (United States)

    Iglesias, V.; Whitlock, C. L.

    2013-12-01

    Patagonian vegetation has dramatically changed in composition and distribution over the last 16,000 years. Although patterns of vegetation change are relatively clear, our understanding of the processes that produce them is limited. In this study, we reconstructed the vegetation and fire history of the North Patagonian forest-steppe ecotone (41 - 43°S) and linked past ecological changes to variations in large-scale synoptic controls of climate and past human activity. Postglacial vegetation and fire dynamics were inferred from high-resolution pollen and charcoal records from seven lakes located along the forest-steppe ecotone in the eastern flanks of the Andes. We fit Mixed Generalized Additive Models to these time series to estimate regional trends in vegetation composition and biomass burning through time, and compared them with independent paleoclimate data so as to assess long-term vegetation-fire-climate linkages. Pollen data indicate that late-glacial steppe was replaced by open forest in the early Holocene and by closed forest in the middle and late Holocene. Fire activity was lowest during the late-glacial to early-Holocene transition and gradually increased through the Holocene. Long-term vegetation and fire patterns responded to variations in seasonal and annual insolation and their effect on moisture during the growing season. Submillennial-scale precipitation variability explained much of the fine-scale ecotonal behavior, mainly through its effect on fire, which can amplify or override the direct influence of climate on ecotone composition. During the late Holocene, in particular, century-long oscillations in forest composition were largely driven by changes in humidity, associated with the strengthening of the westerlies and ENSO variability. Humid periods (4900-3800 cal yr BP, 2850-1350 cal yr BP) promoted Nothofagus forest, and dry times (3800-2850 cal yr BP, 1350-450 cal yr BP) favored Austrocedrus expansion. At intermediate moisture levels

  3. MODELING AND SIMULATION OF THE EFFECT OF THE FIRING CURVE ON THE LINEAR SHRINKAGE OF CERAMIC MATERIALS: LABORATORY SCALE AND INDUSTRIAL SCALE

    Directory of Open Access Journals (Sweden)

    M. Cargnin

    2015-06-01

    Full Text Available AbstractSingle-cycle firing is currently the most widespread method used for the production of ceramic tile. The productivity is directly related to the performance of the constituent materials of the ceramic piece during thermal cycling. Numerical tools which allow the prediction of the material behavior may be of great help in the optimization of this stage. This study addressed the mathematical modeling of the temperature profile within a ceramic tile, together with the sintering kinetics, to simulate the effect of the thermal cycle on the final size. On the laboratory scale, 80 mm x 20 mm specimens with thicknesses of 2.3 mm and 7.8 mm were prepared in order to determine the kinetic constants and validate the model. The application was carried out on an industrial scale, with 450 mm x 450 mm pieces that were 8.0 mm thick. These results show that the model was capable of predicting the experimental results satisfactorily.

  4. Dry sorbent injection of trona to control acid gases from a pilot-scale coal-fired combustion facility

    Directory of Open Access Journals (Sweden)

    Tiffany L. B. Yelverton

    2016-01-01

    Full Text Available  Gaseous and particulate emissions from the combustion of coal have been associated with adverse effects on human and environmental health, and have for that reason been subject to regulation by federal and state governments. Recent regulations by the United States Environmental Protection Agency have further restricted the emissions of acid gases from electricity generating facilities and other industrial facilities, and upcoming deadlines are forcing industry to consider both pre- and post-combustion controls to maintain compliance. As a result of these recent regulations, dry sorbent injection of trona to remove acid gas emissions (e.g. HCl, SO2, and NOx from coal combustion, specifically 90% removal of HCl, was the focus of the current investigation. Along with the measurement of HCl, SO2, and NOx, measurements of particulate matter (PM, elemental (EC, and organic carbon (OC were also accomplished on a pilot-scale coal-fired combustion facility. Gaseous and particulate emissions from a coal-fired combustor burning bituminous coal and using dry sorbent injection were the focus of the current study. From this investigation it was shown that high levels of trona were needed to achieve the goal of 90% HCl removal, but with this increased level of trona injection the ESP and BH were still able to achieve greater than 95% fine PM control. In addition to emissions reported, measurement of acid gases by standard EPA methods were compared to those of an infrared multi-component gas analyzer. This comparison revealed good correlation for emissions of HCl and SO2, but poor correlation in the measurement of NOx emissions.

  5. Biomass fired small-scale CHP technologies - Present status and possibilities

    Energy Technology Data Exchange (ETDEWEB)

    Konttinen, J. (Univ. of Jyvaeskylae, Jyvaeskylae (Finland), Renewable energy programme), e-mail: jukontti@jyu.fi; Linna, V. (VTT Technical Research Centre of Finland, Jyvaeskylae (Finland)), e-mail: veli.linna@vtt.fi; Uusi-Maahi, I. (Keulink Oy, Keuruu (Finland)), e-mail: ilkka.uusi-maahi@keulink.fi

    2010-07-01

    The competitiveness of biomass-fuelled CHP (Combined Heat and Power) production technologies is rising. Small-scale (or micro-CHP) means power and heat production in the scale of 10...1000 kW{sub e} by combustion or gasification of biomass. A survey about the commercial potential and technologies in Europe of micro-CHP was made by the University of Jyvaeskylae and VTT (Technical Research Centre of Finland). The survey was funded by Keulink Oy and Jyvaeskylae Innovation Oy. According to the results of the literature survey, the most promising technologies for power production are based on so called ORC (Organic Rankine Cycle) and Stirling engines. Woody-type of biomass is the best raw material for these applications. With the small-scale technologies, the power production efficiency can vary in the range of 15...30 % of the biomass thermal input. New innovative technologies for small-scale CHP application of woody biomass are being developed by private companies in Central and Northern Finland. Some of these are presented in more detail. The technologies are either based on combustion or gasification of wood-based biomass. Using the product gas in combustion engines requires cleaning, which can be carried out with innovative dry or wet clearing processes. Dry cleaning is possible with catalysts and wet cleaning with scrubbers. The small-scale CHP technologies offer significant potential in local consumption sites of power and heat, such as greenhouses and farms. So called 'eco-villages' are also being built to demonstrate this potential. The possibilities for producing liquid transport fuels, such as biodiesel, are also discussed in this paper. (orig.)

  6. Cable networks, services, and management

    CERN Document Server

    2015-01-01

    Cable Networks, Services, and Management is the first book to cover cable networks, services, and their management, in-depth, for network operators, engineers, researchers, and students. Thirteen experts in various fields have contributed their knowledge of network architectures and services, Operations, Administration, Maintenance, Provisioning, Troubleshooting (OAMPT) for residential and business services, cloud, Software Defined Networks (SDN), as well as virtualization concepts and their applications as part of the future directions of cable networks. The book begins by introducing architecture and services for Data Over Cable Service Interface Specification (DOCSIS) 3.0/ 3.1, Converged Cable Access Platform (CCAP), Content Distribution Networks (CDN, IP TV, and Packet Cable and Wi-Fi for Residential Services. Topics that are discussed in proceeding chapters include: operational systems and management architectures, service orders, provisioning, fault manageme t, performance management, billing systems a...

  7. Non-Intrusive Cable Tester

    Science.gov (United States)

    Medelius, Pedro J. (Inventor); Simpson, Howard J. (Inventor)

    1999-01-01

    A cable tester is described for low frequency testing of a cable for faults. The tester allows for testing a cable beyond a point where a signal conditioner is installed, minimizing the number of connections which have to be disconnected. A magnetic pickup coil is described for detecting a test signal injected into the cable. A narrow bandpass filter is described for increasing detection of the test signal. The bandpass filter reduces noise so that a high gain amplifier provided for detecting a test signal is not completely saturate by noise. To further increase the accuracy of the cable tester, processing gain is achieved by comparing the signal from the amplifier with at least one reference signal emulating the low frequency input signal injected into the cable. Different processing techniques are described evaluating a detected signal.

  8. Longest cable-stayed bridge TATARA; Longest shachokyo Tatara Ohashi

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, K. [Hiroshima University, Hiroshima (Japan). Faculty of Engineering

    1998-06-15

    The world`s longest cable-stayed bridge Tatara having a central span of 890 m had the both ends closed in August 1997, linking Namakuchi Island and Omishima Island. Final finishing work is continuing for opening of the West Seto Expressway in the spring of 1999. A cable-stayed bridge supports the bridge girders by perpendicular components of tensile force of cables stayed obliquely. On the other hand, there is a concern that the girders may have axial compression force generated due to horizontal components of the force from the cable tensile force, which can cause buckling of the girders. Therefore, in order to suspend the girders efficiently by increasing the perpendicular components of the cable force, and moreover to suppress the axial compression force on the girders, it is more advantageous to make bridge towers high, hence the towers of this bridge are highest among the bridges on the Shimanami Ocean Road. This bridge whose long girders are stayed with 21-stage multi cables presented a problem in designing the buckling in steel girders near the towers due to the horizontal components of the force generated by the bridge. Discussions were given, therefore, by using load withstanding force experiments using a whole bridge model of 1/50 scale, buckling experiments on full-size reinforcing plate models, and load withstanding force analysis using a tower model. A number of other technical discussions were repeated, by which the world`s longest cable-stayed bridge was completed. 9 figs., 1 tab.

  9. Dynamic testing of cable structures

    Directory of Open Access Journals (Sweden)

    Caetano Elsa

    2015-01-01

    Full Text Available The paper discusses the role of dynamic testing in the study of cable structures. In this context, the identification of cable force based on vibration measurements is discussed. Vibration and damping assessment are then introduced as the focus of dynamic monitoring systems, and particular aspects of the structural behaviour under environmental loads are analysed. Diverse application results are presented to support the discussion centred on cable-stayed bridges, roof structures, a guyed mast and a transmission line.

  10. Experimental Verification for Cable Force Estimation Using Handheld Shooting of Smartphones

    Directory of Open Access Journals (Sweden)

    Xuefeng Zhao

    2017-01-01

    Full Text Available Currently, due to the rapid development and popularization of smartphones, the usage of ubiquitous smartphones has attracted growing interest in the field of structural health monitoring (SHM. The portable and rapid cable force measurement for cable-supported structures, such as a cable-stayed bridge and a suspension bridge, has an important and practical significance in the evaluation of initial damage and the recovery of transportation networks. The extraction of dynamic characteristics (natural frequencies of cable is considered as an essential issue in the cable force estimation. Therefore, in this study, a vision-based approach is proposed for identifying the natural frequencies of cable using handheld shooting of smartphone camera. The boundary of cable is selected as a target to be tracked in the region of interest (ROI of video image sequence captured by smartphone camera, and the dynamic characteristics of cable are identified according to its dynamic displacement responses in frequency domain. The moving average is adopted to eliminate the noise associated with the shaking of smartphone camera during measurement. A laboratory scale cable model test and a pedestrian cable-stayed bridge test are carried out to evaluate the proposed approach. The results demonstrate the feasibility of using smartphone camera for cable force estimation.

  11. Electromagnetic transients in power cables

    CERN Document Server

    da Silva, Filipe Faria

    2013-01-01

    From the more basic concepts to the most advanced ones where long and laborious simulation models are required, Electromagnetic Transients in Power Cables provides a thorough insight into the study of electromagnetic transients and underground power cables. Explanations and demonstrations of different electromagnetic transient phenomena are provided, from simple lumped-parameter circuits to complex cable-based high voltage networks, as well as instructions on how to model the cables.Supported throughout by illustrations, circuit diagrams and simulation results, each chapter contains exercises,

  12. Design Improvements to Cables and Connectors in the MAJORANA DEMONSTRATOR

    Science.gov (United States)

    Reine, Anna; Haufe, Christopher; Majorana Collaboration

    2017-09-01

    The MAJORANA DEMONSTRATOR is an experiment constructed to search for neutrinoless double-beta decays in germanium-76 and to demonstrate the feasibility to deploy a large-scale experiment in a phased and modular fashion. It consists of two modular arrays of natural and 76Ge-enriched germanium p-type point contact detectors totaling 44.1 kg, located at the 4850' level of the Sanford Underground Research Facility in Lead, South Dakota, USA. The DEMONSTRATOR uses custom high voltage cables to bias the detectors, as well as custom signal cables and connectors to read out the charge deposited at each detector's point contact. These low-mass cables and connectors must meet stringent radiopurity requirements while being subjected to thermal and mechanical stress. A number of issues have been identified with the currently installed cables and connectors. An improved set of cables and connectors for the MAJORANA DEMONSTRATOR are being developed with the aim of increasing their overall reliability and connectivity. We will discuss some of the issues encountered with the current cables and connectors, the initial performance of our improved designs, and applications for development of LEGEND, a next-generation tonne-scale 76Ge experiment. This material is supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, the Particle Astrophysics and Nuclear Physics Programs of the National Science Foundation, and the Sanford Underground Research Facility.

  13. Pilot-scale multistage membrane process for the separation of CO2 from LNG-fired flue gas

    KAUST Repository

    Choi, Seung Hak

    2013-06-01

    In this study, a multistage pilot-scale membrane plant was constructed and operated for the separation of CO2 from Liquefied Natural Gas (LNG)-fired boiler flue gas of 1000 Nm3/day. The target purity and recovery of CO2 were 99 vol.% and 90%, respectively. For this purpose, asymmetric polyethersulfone (PES) hollow fibers membranes has been developed in our previous work and has evaluated the effects of operating pressure and feed concentration of CO2 on separation performance. The operating and permeation data obtained were also analyzed in relation with the numerical simulation data using countercurrent flow model. Based on these results, in this study, four-staged membrane process including dehumidification process has been designed, installed, and operated to demonstrate the feasibility of multistage membrane systems for removing CO2 from flue gases. The operation results using this plant were compared to the numerical simulation results on multistage membrane process. The experimental results matched well with the numerical simulation data. The concentration and the recovery of CO2 in the permeate stream of final stage were ranged from 95-99 vol.% and 70-95%, respectively, depending on the operating conditions. This study demonstrated the applicability of the membrane-based pilot plant for CO2 recovery from flue gas. © 2013 Elsevier B.V. All rights reserved.

  14. Motility of electric cable bacteria

    DEFF Research Database (Denmark)

    Bjerg, Jesper Tataru; Damgaard, Lars Riis; Holm, Simon Agner

    2016-01-01

    Cable bacteria are filamentous bacteria that electrically couple sulfide oxidation and oxygen reduction at centimeter distances, and observations in sediment environments have suggested that they are motile. By time-lapse microscopy, we found that cable bacteria used gliding motility on surfaces...

  15. Fire characteristics charts for fire behavior and U.S. fire danger rating

    Science.gov (United States)

    Faith Ann Heinsch; Pat Andrews

    2010-01-01

    The fire characteristics chart is a graphical method of presenting U.S. National Fire Danger Rating indices or primary surface or crown fire behavior characteristics. A desktop computer application has been developed to produce fire characteristics charts in a format suitable for inclusion in reports and presentations. Many options include change of scales, colors,...

  16. Orienting the camera and firing lasers to enhance large scale particle image velocimetry for streamflow monitoring

    Science.gov (United States)

    Tauro, Flavia; Porfiri, Maurizio; Grimaldi, Salvatore

    2014-09-01

    Large scale particle image velocimetry (LSPIV) is a nonintrusive methodology for continuous surface flow monitoring in natural environments. Recent experimental studies demonstrate that LSPIV is a promising technique to estimate flow discharge in riverine systems. Traditionally, LSPIV implementations are based on the use of angled cameras to capture extended fields of view; images are then orthorectified and calibrated through the acquisition of ground reference points. As widely documented in the literature, the identification of ground reference points and image orthorectification are major hurdles in LSPIV. Here we develop an experimental apparatus to address both of these issues. The proposed platform includes a laser system for remote frame calibration and a low-cost camera that is maintained orthogonal with respect to the water surface to minimize image distortions. We study the feasibility of the apparatus on two complex natural riverine environments where the acquisition of ground reference points is prevented and illumination and seeding density conditions are challenging. While our results confirm that velocity estimations can be severely affected by inhomogeneously seeded surface tracers and adverse illumination settings, they demonstrate that LSPIV implementations can benefit from the proposed apparatus. Specifically, the presented system opens novel avenues in the development of stand-alone platforms for remote surface flow monitoring.

  17. Cable Bacteria in Freshwater Sediments

    DEFF Research Database (Denmark)

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable...... bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures...... marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary...

  18. Full-scale and model studies on fire propagation in textile belts for use in coal mines. Untersuchungen im natuerlichen Massstab und im Modell ueber die Brandausbreitung an Textil-Foerdergurten fuer den Steinkohlenbergbau

    Energy Technology Data Exchange (ETDEWEB)

    Heyn, W.

    1984-12-13

    Fire propagation in mines is largely influenced by the inflammation and burning characteristics of the conveyor belts. The author's experiments served to supplement the findings of experiments in fire test stands and in the laboratory. The influence of different parameters on fire propagation in textile belts is investigated. Test facility experiments cannot always be replaced by simple model-scale experiments in the laboratory. (HLN).

  19. Tunnel fire dynamics

    CERN Document Server

    Ingason, Haukur; Lönnermark, Anders

    2015-01-01

    This book covers a wide range of issues in fire safety engineering in tunnels, describes the phenomena related to tunnel fire dynamics, presents state-of-the-art research, and gives detailed solutions to these major issues. Examples for calculations are provided. The aim is to significantly improve the understanding of fire safety engineering in tunnels. Chapters on fuel and ventilation control, combustion products, gas temperatures, heat fluxes, smoke stratification, visibility, tenability, design fire curves, heat release, fire suppression and detection, CFD modeling, and scaling techniques all equip readers to create their own fire safety plans for tunnels. This book should be purchased by any engineer or public official with responsibility for tunnels. It would also be of interest to many fire protection engineers as an application of evolving technical principles of fire safety.

  20. Global relationship of fire occurrence and fire intensity: A test of intermediate fire occurrence-intensity hypothesis

    Science.gov (United States)

    Luo, Ruisen; Hui, Dafeng; Miao, Ning; Liang, Chuan; Wells, Nicholas

    2017-05-01

    Fire plays a significant role in global atmosphere and biosphere carbon and nutrient cycles. Globally, there are substantially different distributions and impacts between fire occurrence and fire intensity. It is prominent to have a thorough investigation of global relationship between fire occurrence and fire intensity for future fire prediction and management. In this study, we proposed an intermediate fire occurrence-intensity (IFOI) hypothesis for the global relationship between fire occurrence and fire intensity, suggesting that fire occurrence changes with fire intensity following a humped relationship. We examined this hypothesis via satellite data from January 2001 to December 2013 at a global scale, and in small and large fire intensity zones, respectively. Furthermore, the fire occurrence and fire intensity relationship was developed among different vegetation types to reveal the changes of parameters and strengths. Finally, the environmental factors (including climatic, hydraulic, biological, and anthropogenic variables) underpinning the fire occurrence and intensity pattern were evaluated for the underlying mechanisms. The results supported our IFOI hypothesis and demonstrated that the humped relationship is driven by different causes among vegetation types. Fire occurrence increases with fire intensity in small fire intensity zones due to alleviation of the factors limiting both fire occurrence and intensity. Beyond a certain fire intensity threshold, fire occurrence is constrained, probably due to the limitation of available fuels. The information generated in this study could be helpful for understanding global variation of fire occurrence and fire intensity due to fire-vegetation-climate-human interactions and facilitating future fire management.

  1. Post-fire changes in sediment transport connectivity from pedon to watershed scale. The Navalón wildfire in Eastern Spain

    Science.gov (United States)

    Cerdà, Artemi; Bodí, Merche B.; González, Óscar; Mataix Solera, Jorge; Doerr, Stefan Helmut

    2015-04-01

    Wildfire are present in the Earth System since vegetation was present in the continents (Doerr and Cerdà, 2005; Kaiho et al., 2013). Forest fire cause damage in the soil and the vegetation cover (Guénon et al., 2013). The years after a forest fire there is a sudden increase in the soil erosion rates that contribute to connect the pedon, slope tram, tram and watershed with surface flows that results in high erosion rates (Cerdà and Lasanta, 2005; Lasanta and Cerdà, 2005; Cawson et al., 2012; Pérez Cabello et al., 2012; Prats et al., 2015). Although the research on soil erosion after forest fire was carried out at different scales by different authors, there is not information about soil erosion at different scales at the same research site and during the post fire period. After the forest fire of April 2008 in Navalón, Eastern Spain, the Soil Erosion and Degradation Research Group from the University of Valencia initiated the measurement of the soil losses at pedon scale (microplots of 0.30 m2), at slope tram (silt fences of 1.8 m width), at slope scale (abandoned terraces) and at watershed scale, at the bottom of the valley (abandoned terraces). The results show that there is a reduction in the sediment yield from pedon to watershed scale and that the soil erosion took place in the first year after the fire. Acknowledgements To the "Ministerio de Economía and Competitividad" of Spanish Government for finance the POSTFIRE project (CGL2013- 47862-C2-1-R). The research projects GL2008-02879/BTE, LEDDRA 243857 and PREVENTING AND REMEDIATING DEGRADATION OF SOILS IN EUROPE THROUGH LAND CARE (RECARE)FP7-ENV-2013- supported this research. References Carreiras, M., Ferreira, A.J.D., Valente, S., Fleskens, L., Gonzales-Pelayo, Ó., Rubio, J.L., Stoof, C.R., Coelho, C.O.A., Ferreira, C.S.S., Ritsema, C.J. 2014. Comparative analysis of policies to deal with the wildfire risk. Land Degradation & Development, 25, 92-103. http://dx.doi.org/10.1002/ldr.2274 Cawson, J. G

  2. Fire danger and fire behavior modeling systems in Australia, Europe, and North America

    Science.gov (United States)

    Francis M. Fujioka; A. Malcolm Gill; Domingos X. Viegas; B. Mike Wotton

    2009-01-01

    Wildland fire occurrence and behavior are complex phenomena involving essentially fuel (vegetation), topography, and weather. Fire managers around the world use a variety of systems to track and predict fire danger and fire behavior, at spatial scales that span from local to global extents, and temporal scales ranging from minutes to seasons. The fire management...

  3. Ames T-3 fire test facility - Aircraft crash fire simulation

    Science.gov (United States)

    Fish, R. H.

    1976-01-01

    There is a need to characterize the thermal response of materials exposed to aircraft fuel fires. Large scale open fire tests are costly and pollute the local environment. This paper describes the construction and operation of a subscale fire test that simulates the heat flux levels and thermochemistry of typical open pool fires. It has been termed the Ames T-3 Test and has been used extensively by NASA since 1969 to observe the behavior of materials exposed to JP-4 fuel fires.

  4. Structural Health Monitoring approach for detecting ice accretion on bridge cable using the Haar Wavelet Transform

    DEFF Research Database (Denmark)

    Andre, Julia; Kiremidjian, Anne; Liao, Yizheng

    2016-01-01

    of the structure. In this paper, an ice accretion detection algorithm is presented based on the Continuous Wavelet Transform (CWT). In the proposed algorithm, the acceleration signals obtained from bridge cables are transformed using wavelet method. The damage sensitive features (DSFs) are de fined as a function...... of the wavelet energy at specific wavelet scales. It is found that as ice accretes on the cables, the mass of cable increases, thus changing the wavelet energies. Hence, the DSFs can be used to track the change of cables mass. To validate the proposed algorithm, we use the data collected from a laboratory...

  5. A full 3D time-dependent electromagnetic model for Roebel cables

    DEFF Research Database (Denmark)

    Rodriguez Zermeno, Victor Manuel; Grilli, Francesco; Sirois, Frederic

    2013-01-01

    current sharing among them. However, since Roebel cables have a true 3D structure and are made of several high aspect ratio coated conductors, modelling and simulation of their electromagnetic properties is very challenging. Therefore, a realistic model taking into account the actual layout of the cable...... is unavoidably a large scale computational problem. In this work, we present a full 3D model of a Roebel cable with 14 strands. The model is based on the H-formulation, widely used for 2D problems. In order to keep the 3D features of the cable (in particular the magnetization currents near the transpositions...

  6. Offshore Wind Farm Cable Connection Configuration Optimization using Dynamic Minimum Spanning Tree Algorithm

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Chen, Zhe

    2015-01-01

    Anew approach, Dynamic Minimal Spanning Tree (DMST) algorithm, whichisbased on the MST algorithm isproposed in this paper to optimizethe cable connectionlayout for large scale offshore wind farm collection system. The current carrying capacity of the cable is considered as the main constraint....... Thedynamic changing of the cable capacity, therefore, the cost during the searching process is presented in this work. Twowind farms arechosen as the studied case and the final results showthat the proposed methodcan save the investment on cables 1.07% and 6.10% respectively compared with MST method...

  7. Error Correction of EMTDC Line and Cable Series Impedance Calculations Compared to Traditional Methods

    DEFF Research Database (Denmark)

    Sørensen, Stefan; Nielsen, Hans Ove

    2002-01-01

    In this paper we present comparison of different line and cable series impedance calculation methods, where the correction of a discovered PSCAD/EMIDC v.3.0.8 calculation error of the cable series impedance results n deviation under 0.1% instead of the previous method which gave approximately 10%......% deviation to other methods. The correction is done by adjusting he earth return path impedance for the cable model, and will thereby form the basis for a future comparison with measured data from a real full scale earth fault experiment on a mixed line and cable network.......In this paper we present comparison of different line and cable series impedance calculation methods, where the correction of a discovered PSCAD/EMIDC v.3.0.8 calculation error of the cable series impedance results n deviation under 0.1% instead of the previous method which gave approximately 10...

  8. Full Scale Deposition Trials at 150 MWe PF-boiler Co-firing COal and Straw: Summary of Results

    DEFF Research Database (Denmark)

    Andersen, Karin Hedebo; Frandsen, Flemming; Hansen, Peter Farkas Binderup

    1999-01-01

    A conventional PF-fired boiler at the Danish energy company I/S Midtkraft has been converted to coal-straw co-combustion and a two-year demonstration programme was initiated in January 1996 addressing several aspects of coal-straw co-combustion. Deposition trials were performed as part of the dem......A conventional PF-fired boiler at the Danish energy company I/S Midtkraft has been converted to coal-straw co-combustion and a two-year demonstration programme was initiated in January 1996 addressing several aspects of coal-straw co-combustion. Deposition trials were performed as part...... for the coal types utilised in the tests.The deposit formation observed during co-firing with up to 20% straw (energy basis), does not lead to fouling and slagging problems which cannot be overcome by increased sootblowing when firing the two coals used in the demonstration programme. However, slagging...

  9. 10BASE5 Ethernet Cable & Vampire Tap

    CERN Multimedia

    1983-01-01

    10BASE5 Thick Ethernet Cable, 10Mbit/sec. In the 1980s and early 1990's, Ethernet became more popular and provided a much faster data transmission rate. This cable is one of the first ethernet cables from 1983, a thick, bulky affair. Computers were attached via "Vampire Taps" which were connectors screwed straight through the shielding of the cable.

  10. 14 CFR 27.1365 - Electric cables.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Electric cables. 27.1365 Section 27.1365... STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Electrical Systems and Equipment § 27.1365 Electric cables. (a) Each electric connecting cable must be of adequate capacity. (b) Each cable that would overheat...

  11. Prospects for co-firing of clean coal and creosote-treated waste wood at small-scale power stations

    Directory of Open Access Journals (Sweden)

    Zandersons Janis

    2006-01-01

    Full Text Available If a small-scale clean coal fueled power plant is co-fueled with 5% of creosote-treated used-up sleeper wood, the decontamination by carbonisation at 500 °C in an indirectly heated rotary kiln with the diameter 1.7 m and effective length 10 m can be realized. It should be included in the "3R Clean Coal Carbonisation Plant" system, which processes coal. It will improve the heat balance of the system, since the carbonisation of wood will deliver a lot of high caloricity pyroligneous vapour to the joint furnace of the "3R Clean Coal Carbonisation Plant". Pine wood sleeper sapwood contains 0.25% of sulphur, but the average pine sleeper wood (sapwood and heartwood 0.05% of sulphur. Most of the sulphur is lost with the pyroligneous vapour and burned in the furnace. Since the "3R Clean Coal Carbonisation Plant" is equipped with a flue gases cleaning system, the SO2 emission level will not exceed 5 mg/m3. The charcoal of the sapwood portion of sleepers and that of the average sleeper wood will contain 0.22% and 0.035% of sulphur, respectively. The increase of the carbonisation temperature does not substantially decrease the sulphur content in charcoal, although it is sufficiently low, and the charcoal can be co-fired with clean coal. The considered process is suitable for small power plants, if the biomass input in the common energy balance is 5 to 10%. If the mean distance of sleepers transportation for Central and Eastern Europe is estimated not to exceed 200 km, the co-combustion of clean coal and carbonized sleepers would be an acceptable option from the environmental and economic points of view.

  12. Emerging Subsea Networks: SMART Cable Systems for Science and Society

    Science.gov (United States)

    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

  13. Fire History

    Data.gov (United States)

    California Department of Resources — The Fire Perimeters data consists of CDF fires 300 acres and greater in size and USFS fires 10 acres and greater throughout California from 1950 to 2002. Some fires...

  14. Fire Perimeters

    Data.gov (United States)

    California Department of Resources — The Fire Perimeters data consists of CDF fires 300 acres and greater in size and USFS fires 10 acres and greater throughout California from 1950 to 2003. Some fires...

  15. Thermal analysis of underground power cable system

    Science.gov (United States)

    Rerak, Monika; Ocłoń, Paweł

    2017-10-01

    The paper presents the application of Finite Element Method in thermal analysis of underground power cable system. The computations were performed for power cables buried in-line in the ground at a depth of 2 meters. The developed mathematical model allows determining the two-dimensional temperature distribution in the soil, thermal backfill and power cables. The simulations studied the effect of soil and cable backfill thermal conductivity on the maximum temperature of the cable conductor. Also, the effect of cable diameter on the temperature of cable core was studied. Numerical analyses were performed based on a program written in MATLAB.

  16. Background information to the installers guide for small scale mains connected PV

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    This report contains background information used by BRE, EA Technology, Halcrows and Sundog when compiling guidance for the UK's New and Renewable Energy Programme on the installation of small-scale photovoltaics (PV) in buildings. The report considers: relevant standards; general safety issues; fire and safety issues, including the fire resistance of PV modules; PV module ratings such as maximum voltage and maximum current; DC cabling; the DC disconnect; the DC junction box; fault analysis; general and AC side earthing; DC earthing; lightning and surge suppression; inverters; AC modules; AC systems; getting connection; mounting options; and installation issues.

  17. Air flow around suspended cables

    Science.gov (United States)

    Gołębiowska, Irena; Dutkiewicz, Maciej

    The impact of wind on construction structures is essential issue in design and operation. In particular, the wind can cause the dengerous vibrations of slender structures with low rigidity, eg. vibrations of cables of suspension and cable-stayed bridges or high voltage transmision lines, thus understanding of wind flow around such constructions is significant. In the paper the results of the analysis of wind flow around the cables for different Reynolds number is presented. The analysed flow meets the Navier-Stokes and continuity equations. The circle and elipse section of the cable is analysed. The discusion of vorticity, drag and lift coefficients and cases due to different angle of wind flow action is presented. The boundary layer and its infuence on total flow is analysed.

  18. Air flow around suspended cables

    Directory of Open Access Journals (Sweden)

    Gołębiowska Irena

    2017-01-01

    Full Text Available The impact of wind on construction structures is essential issue in design and operation. In particular, the wind can cause the dengerous vibrations of slender structures with low rigidity, eg. vibrations of cables of suspension and cable-stayed bridges or high voltage transmision lines, thus understanding of wind flow around such constructions is significant. In the paper the results of the analysis of wind flow around the cables for different Reynolds number is presented. The analysed flow meets the Navier-Stokes and continuity equations. The circle and elipse section of the cable is analysed. The discusion of vorticity, drag and lift coefficients and cases due to different angle of wind flow action is presented. The boundary layer and its infuence on total flow is analysed.

  19. Motility of electric cable bacteria

    DEFF Research Database (Denmark)

    Bjerg, Jesper Tataru; Damgaard, Lars Riis; Holm, Simon Agner

    2016-01-01

    Cable bacteria are filamentous bacteria that electrically couple sulfide oxidation and oxygen reduction at centimeter distances, and observations in sediment environments have suggested that they are motile. By time-lapse microscopy, we found that cable bacteria used gliding motility on surfaces...... with a highly variable speed of 0.50.3 ms1 (meanstandard deviation) and time between reversals of 155108 s. They frequently moved forward in loops, and formation of twisted loops revealed helical rotation of the filaments. Cable bacteria responded to chemical gradients in their environment, and around the oxic......-anoxic interface, they curled and piled up, with straight parts connecting back to the source of sulfide. Thus, it appears that motility serves the cable bacteria in establishing and keeping optimal connections between their distant electron donor and acceptors in a dynamic sediment environment....

  20. Cable SGEMP Code Validation Study

    Energy Technology Data Exchange (ETDEWEB)

    Ballard, William Parker [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Center for CA Weapons Systems Engineering

    2013-05-01

    This report compared data taken on the Modular Bremsstrahlung Simulator using copper jacketed (cujac) cables with calculations using the RHSD-RA Cable SGEMP analysis tool. The tool relies on CEPXS/ONBFP to perform radiation transport in a series of 1D slices through the cable, and then uses a Green function technique to evaluate the expected current drive on the center conductor. The data were obtained in 2003 as part of a Cabana verification and validation experiment using 1-D geometries, but were not evaluated until now. The agreement between data and model is not adequate unless gaps between the dielectric and outer conductor (ground) are assumed, and these gaps are large compared with what is believed to be in the actual cable.

  1. Static and Dynamic Characteristics of a Long-Span Cable-Stayed Bridge with CFRP Cables

    Directory of Open Access Journals (Sweden)

    Xu Xie

    2014-06-01

    Full Text Available In this study, the scope of CFRP cables in cable-stayed bridges is studied by establishing a numerical model of a 1400-m span of the same. The mechanical properties and characteristics of CFRP stay cables and of a cable-stayed bridge with CFRP cables are here subjected to comprehensive analysis. The anomalies in the damping properties of free vibration, nonlinear parametric vibration and wind fluctuating vibration between steel cables and CFRP cables are determined. The structural stiffness, wind resistance and traffic vibration of the cable-stayed bridge with CFRP cables are also analyzed. It was found that the static performances of a cable-stayed bridge with CFRP cables and steel cables are basically the same. The natural frequencies of CFRP cables do not coincide with the major natural frequencies of the cable-stayed bridge, so the likelihood of CFRP cable-bridge coupling vibration is minuscule. For CFRP cables, the response amplitudes of both parametric vibration and wind fluctuating vibration are smaller than those of steel cables. It can be concluded from the research that the use of CFRP cables does not change the dynamic characteristics of the vehicle-bridge coupling vibration. Therefore, they can be used in long-span cable-stayed bridges with an excellent mechanical performance.

  2. An overview of the ITER cabling network and cable database management

    Energy Technology Data Exchange (ETDEWEB)

    Sonara, Jashwant, E-mail: jashwant.Sonara@iter.org [ITER Organization, Route de Vinon sur Verdon, CS 90 046-13067, Saint Paul Lez Durance (France); Beltran, David; Pintea, Bogdan; Hourtoule, Joel; Benfatto, Ivone [ITER Organization, Route de Vinon sur Verdon, CS 90 046-13067, Saint Paul Lez Durance (France); Kim, Sung Hoon; Lee, Kun Ho; Jung, Sun Kyung; Lee, Cheoung-Joon [KEPCO E& C, Yonggudaero, Giheung-gu, Yongin-si, Gyeonggi-do, 446-713 (Korea, Republic of)

    2015-10-15

    Highlights: • More than 80,000 cables have been registered into ITER centralized cable database. • This cabling represents 28 ITER plant systems and 21,000 equipments including 61,000 non-safety cables and 7300 safety cables. • Development of unique cable engineering management system for diversified cabling requirement. • Use of 2D and 3D softwares and integration of both softwares into bespoke software which can handle 2D and 3D features of the tray network. - Abstract: ITER is a nuclear fusion facility, where many systems with varying functional and physical characteristics coexist. This makes the cabling requirements diverse too. The design of the ITER demands extensive integration of many systems interfaces. This process starts by collating cable requirement data to form a giant cable database with scope for approximately 120,000 cables in total. Ultimately the cabling installation will be approximately twice the size of one required for a 3rd generation nuclear fission power plant, with cables spanning more than 12,000 km to be installed within approximately 200 km of cable trays. Considering the differing cabling requirements, the raceway network and cables shall be routed in a prescribed manner to comply with French Nuclear Safety standards. This paper describes an overview of the ITER cabling network, the cable engineering design workflow, development and management of the cable database and integration between the software tools.

  3. ELECTROSTATIC PROCESSES IN POWER CABLES

    Directory of Open Access Journals (Sweden)

    G.V. Bezprozvannych

    2013-09-01

    Full Text Available Observation of contact electrification of power cable samples is made. It is revealed that the contact potential difference and the capacity formed under separation of free charges on the surfaces of the contacting materials depend on cable design, applied materials, and inspection schemes. Time series of capacity drift and dielectric loss tangent caused by instability of triboelectric charging of the contacting surfaces are presented.

  4. Cable Driven Devices for Telemanipulation

    OpenAIRE

    Ferraresi, Carlo; Pescarmona, Francesco

    2010-01-01

    Cable driven robotic devices present peculiar aspects, requiring the solution of very specific problems. As regards the determination of the main operational characteristics, like the workspace, it is necessary to consider that such devices are often parallel and redundant structures. Moreover, cables can only exert traction forces. As a consequence, the development of such structures requires coping with two main aspects: (a) the solution of forward kinematics and inverse statics, necessary ...

  5. Co-emergence of multi-scale cortical activities of irregular firing, oscillations and avalanches achieves cost-efficient information capacity.

    Directory of Open Access Journals (Sweden)

    Dong-Ping Yang

    2017-02-01

    Full Text Available The brain is highly energy consuming, therefore is under strong selective pressure to achieve cost-efficiency in both cortical connectivities and activities. However, cost-efficiency as a design principle for cortical activities has been rarely studied. Especially it is not clear how cost-efficiency is related to ubiquitously observed multi-scale properties: irregular firing, oscillations and neuronal avalanches. Here we demonstrate that these prominent properties can be simultaneously observed in a generic, biologically plausible neural circuit model that captures excitation-inhibition balance and realistic dynamics of synaptic conductance. Their co-emergence achieves minimal energy cost as well as maximal energy efficiency on information capacity, when neuronal firing are coordinated and shaped by moderate synchrony to reduce otherwise redundant spikes, and the dynamical clusterings are maintained in the form of neuronal avalanches. Such cost-efficient neural dynamics can be employed as a foundation for further efficient information processing under energy constraint.

  6. Mechanistic Model for Ash Deposit Formation in Biomass Suspension-Fired Boilers. Part 2: Model Verification by Use of Full Scale Tests

    DEFF Research Database (Denmark)

    Hansen, Stine Broholm; Jensen, Peter Arendt; Jappe Frandsen, Flemming

    2017-01-01

    A model for deposit formation in suspension firing of biomass has been developed. The model describes deposit build-up by diffusion and subsequent condensation of vapors, thermoforesis of aerosols, convective diffusion of small particles, impaction of large particles and reaction. The model...... describes particle sticking or rebound by a combination of the description of (visco)elsatic particles impacting a solid surface and particle capture by a viscous surface. The model is used to predict deposit formation rates measured during tests conducted with probes in full-scale suspension-fired biomass...... boilers. The rates predicted by the model was reasonably able to follow the rates observed in the tests, although with some variation, primarily as overestimations of the deposit formation rates. It is considered that the captive properties of the deposit surface are overestimated. Further examination...

  7. The distribution of grasslands, savannas and forests in Africa: a new look at the relationships between vegetation, fire and climate at continental scale

    Science.gov (United States)

    D'Onofrio, Donatella; von Hardenberg, Jost; Baudena, Mara

    2017-04-01

    Savannas occupy about a fifth of the global land surface and store approximately 15% of the terrestrial carbon. They also encompass about 85% of the global land area burnt annually. Along an increasing rainfall gradient, they are the intermediate biome between grassland and forest. Undergoing and predicted increasing temperature and CO2 concentration, modified precipitation regimes, as well as increasing land-use intensity, are expected to induce important shifts in savanna structure and in the distribution of grasslands, savannas and forests. Owing to the large extent and productivity of savanna biomes, these changes could have larger impacts on the global biogeochemical cycle and precipitation than for any other biome, thus influencing the vegetation-climate system. The dynamics of these biomes has been long studied, and the current theory postulates that while arid savannas are observed because of tree-water limitation, and competition with grasses, in mesic conditions savannas persist because a grass-fire feedback exists, which can maintain them as an alternatively stable state to closed forests. This feedback is reinforced by the different responses of savanna and forest tree type. In this context, despite their relevance, grasses and tree types have been studied mostly in small scale ecological studies, while continental analyses focused on total tree cover only. Here we analyze a recent MODIS product including explicitly the non-tree vegetation cover, allowing us to illustrate for the first time at continental scale the importance of grass cover and of tree-fire responses in determining the emergence of the different biomes. We analyze the relationships of woody and herbaceous cover with fire return time (all from MODIS satellite observations), rainfall annual average and seasonality (from TRMM satellite measurements), and we include tree phenology information, based on the ESA Global Land Cover map, also used to exclude areas with large anthropogenic land

  8. Co-firing Bosnian coals with woody biomass: Experimental studies on a laboratory-scale furnace and 110 MWe power unit

    Directory of Open Access Journals (Sweden)

    Smajevic Izet

    2012-01-01

    Full Text Available This paper presents the findings of research into cofiring two Bosnian cola types, brown coal and lignite, with woody biomass, in this case spruce sawdust. The aim of the research was to find the optimal blend of coal and sawdust that may be substituted for 100% coal in large coal-fired power stations in Bosnia and Herzegovina. Two groups of experimental tests were performed in this study: laboratory testing of co-firing and trial runs on a large-scale plant based on the laboratory research results. A laboratory experiment was carried out in an electrically heated and entrained pulverized-fuel flow furnace. Coal-sawdust blends of 93:7% by weight and 80:20% by weight were tested. Co-firing trials were conducted over a range of the following process variables: process temperature, excess air ratio and air distribution. Neither of the two coal-sawdust blends used produced any significant ash-related problems provided the blend volume was 7% by weight sawdust and the process temperature did not exceed 1250ºC. It was observed that in addition to the nitrogen content in the co-fired blend, the volatile content and particle size distribution of the mixture also influenced the level of NOx emissions. The brown coal-sawdust blend generated a further reduction of SO2 due to the higher sulphur capture rate than for coal alone. Based on and following the laboratory research findings, a trial run was carried out in a large-scale utility - the Kakanj power station, Unit 5 (110 MWe, using two mixtures; one in which 5%/wt and one in which 7%/wt of brown coal was replaced with sawdust. Compared to a reference firing process with 100% coal, these co-firing trials produced a more intensive redistribution of the alkaline components in the slag in the melting chamber, with a consequential beneficial effect on the deposition of ash on the superheater surfaces of the boiler. The outcome of the tests confirms the feasibility of using 7%wt of sawdust in combination

  9. Probabilistic Fatigue Life Prediction of Bridge Cables Based on Multiscaling and Mesoscopic Fracture Mechanics

    Directory of Open Access Journals (Sweden)

    Zhongxiang Liu

    2016-04-01

    Full Text Available Fatigue fracture of bridge stay-cables is usually a multiscale process as the crack grows from micro-scale to macro-scale. Such a process, however, is highly uncertain. In order to make a rational prediction of the residual life of bridge cables, a probabilistic fatigue approach is proposed, based on a comprehensive vehicle load model, finite element analysis and multiscaling and mesoscopic fracture mechanics. Uncertainties in both material properties and external loads are considered. The proposed method is demonstrated through the fatigue life prediction of cables of the Runyang Cable-Stayed Bridge in China, and it is found that cables along the bridge spans may have significantly different fatigue lives, and due to the variability, some of them may have shorter lives than those as expected from the design.

  10. Seismic Fragility Assessment of an Isolated Multipylon Cable-Stayed Bridge Using Shaking Table Tests

    Directory of Open Access Journals (Sweden)

    Yutao Pang

    2017-01-01

    Full Text Available In recent decades, cable-stayed bridges have been widely built around the world due to the appealing aesthetics and efficient and fast mode of construction. Numerous studies have concluded that the cable-stayed bridges are sensitive to earthquakes because they possess low damping characteristics and high flexibility. Moreover, cable-stayed bridges need to warrant operability especially in the moderate-to-severe earthquakes. The provisions implemented in the seismic codes allow obtaining adequate seismic performance for the cable-stayed bridge components; nevertheless, they do not provide definite yet reliable rules to protect the bridge. To date, very few experimental tests have been carried out on the seismic fragility analysis of cable-stayed bridges which is the basis of performance-based analyses. The present paper is aimed at proposing a method to derive the seismic fragility curves of multipylon cable-stayed bridge through shake table tests. Toward this aim, a 1/20 scale three-dimensional model of a 22.5 m cable-stayed bridge in China is constructed and tested dynamically by using the shaking table facility of Tongji University. The cable-stayed bridge contains three pylons and one side pier. The outcomes of the comprehensive shaking table tests carried out on cable-stayed bridge have been utilized to derive fragility curves based on a systemic approach.

  11. Optimization of investment economic in PCI using the methodology of benefits design in analysis of the spread of fires with FDS (Fire Dynamics Simulator) in areas of nuclear fire; Optimizacion de la inversion economica en PCI mediante la metodologia de diseo prestaional en el analisis de la propagacion de incendios con FDS (Fire Dynnamics Simulator) en areas de fuego de centrales nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Salellas, J.

    2015-07-01

    Fire simulation analysis allows knowing the evolution and spread fire in areas of interest within a NPP such as control room, cable room and multi zone comportment among others. fires are a main concern regarding safety analysis of NPP. IDOM has the capability to carry out fire simulations, taken in to account smoke control, fire spread, toxicity levels, ventilation and all physical phenomena. As a result, appropriate fire protection measures can be assessed in each scenario. CFD tools applied to fire simulations can determine with higher resolution all damages caused during the fire. Furthermore, such tools can reduce costs due to a lower impact of design modifications. (Author)

  12. Ocean Observing using SMART subsea telecommunications cable systems

    Science.gov (United States)

    Howe, B. M.

    2015-12-01

    Planning is underway to integrate ocean sensors into SMART subsea cable systems providing basin and ultimately global array coverage within the next decades (SMART: Scientific Monitoring And Reliable Telecommunications). SMART cables will: contribute to the understanding of ocean dynamics and climate; improve knowledge of earthquakes and forecasting of tsunamis; and complement and enhance existing satellite and in-situ observing systems. SMART cables will be a first order addition to the ocean observing system, with unique contributions, strengthening and complementing satellite and in situ systems. Cables spanning the ocean basins with repeaters every ~50 km will host sensors/mini-observatories, providing power and real-time communications. The current global infrastructure of commercial submarine telecommunications cable systems consists of 1 Gm of cable with ~20,000 repeaters (to boost optical signals); the overall system is refreshed and expanded on time scales of 10 - 20 years and individual systems have lifetimes in excess of 25 years. Initial instrumentation of the cables with bottom temperature, pressure and acceleration sensors will provide unique information for monitoring and studying climate change and for improved tsunami and earthquake warning. These systems will be a new highly reliable, long-lived component of the ocean observing system, complementing satellite, float and other in situ platforms and measurements. Several UN agencies, the International Telecommunication Union, the World Meteorological Organization, and the UNESCO Intergovernmental Oceanographic Commission have formed a Joint Task Force to move this concept to fruition (ITU/WMO/IOC JTF; http://www.itu.int/en/ITU-T/climatechange/task-force-sc). A review of the overall planning effort and two NASA-funded workshops focusing on the ocean circulation and climate is presented. [Funding provided by NASA.

  13. Landscape-scale fire restoration on the big piney ranger district in the Ozark highlands of Arkansas

    Science.gov (United States)

    John Andre; McRee Anderson; Douglas Zollner; Marie Melnechuk; Theo Witsell

    2009-01-01

    The Ozark-St. Francis National Forest, The Nature Conservancy (TNC), the Arkansas Natural Heritage Commission, Arkansas Forestry Commission, private landowners, and others are currently engaged in a collaborative project to restore the oak-hickory and pine-oak ecosystems of the Ozark Highlands on 60,000 acres of the Big Piney Ranger District. Frequent historical fires...

  14. Full-scale Milling Tests of Wood Pellets for Combustion in a Suspension-Fired Power Plant Boiler

    DEFF Research Database (Denmark)

    Masche, Marvin; Puig Arnavat, Maria; Wadenbäck, Johan

    The size reduction of pelletized wood is crucial in suspension-fired power plants, and hence its milling characteristics are of interest to optimize the milling and combustion process. The objective of the study was to compare the size and shape of pellets disintegrated in hot water with that fro...

  15. Combustion performance of pyrolysis oil/ethanol blends in a residential-scale oil-fired boiler

    Science.gov (United States)

    A 40 kWth oil-fired commercial boiler was fueled with blends of biomass pyrolysis oil (py-oil) and ethanol to determine the feasibility of using these blends as a replacement for fuel oil in home heating applications. An optimal set of test parameters was determined for the combustion of these blend...

  16. Landscape-scale fuel treatment and wildfire impacts on carbon stocks and fire hazard in California spotted owl habitat

    Science.gov (United States)

    Lindsay A. Chiono; Danny L. Fry; Brandon M. Collins; Andrea H. Chatfield; Scott L. Stephens

    2017-01-01

    Forest managers are challenged with meeting numerous demands that often include wildlife habitat and carbon (C) sequestration. We used a probabilistic framework of wildfire occurrence to (1) estimate the potential for fuel treatments to reduce fire risk and hazard across the landscape and within protected California spotted owl (Strix occidentalis...

  17. Static and Dynamic Mechanical Properties of Long-Span Cable-Stayed Bridges Using CFRP Cables

    Directory of Open Access Journals (Sweden)

    Mei Kuihua

    2017-01-01

    Full Text Available The elastic modulus and deadweight of carbon fiber-reinforced polymer (CFRP cables are different from those of steel cables. Thus, the static and dynamic behaviors of cable-stayed bridges using CFRP cables are different from those of cable-stayed bridges using steel cables. The static and dynamic performances of the two kinds of bridges with a span of 1000 m were studied using the numerical method. The effects of geometric nonlinear factors on static performance of the two kinds of cable-stayed bridges were analyzed. The live load effects and temperature effects of the two cable-stayed bridges were also analyzed. The influences of design parameters, including different structural systems, the numbers of auxiliary piers, and the space arrangement types of cable, on the dynamic performance of the cable-stayed bridge using CFRP cables were also studied. Results demonstrate that sag effect of the CFRP cable is much smaller than that of steel cable. The temperature effects of CFRP cable-stayed bridge are less than those of steel cable-stayed bridge. The vertical bending natural vibration frequency of the CFRP cable-stayed bridge is generally lower than that of steel cable-stayed bridge, whereas the torsional natural vibration frequency of the former is higher than that of the latter.

  18. Laplace Synthesis Validation through Measurements on Underground Transmission Cables

    Directory of Open Access Journals (Sweden)

    Uribe-Campos Felipe Alejandro

    2014-10-01

    Full Text Available Underground cable electrical parameters ZY as well as their modal propagation characteristics are highly frequency dependent which in certain cases turns its analysis difficult. To perform electromagnetic transient studies of cables the calculation of electrical parameters is essential to obtain the waves propagation solution through the multiconductor system. At the same time this requires to solve the inverse Laplace transform on a numerical form. Although the analytic Laplace transform has an indisputable accuracy, the application of its numerical version up-to-date has not been completely accepted. A complete methodology is developed in this work to guide analyst engineers or graduate students in the calculation of electromagnetic transients of underground cable systems. Finally, to help the validation of the numerical inverse Laplace transform a scaled prototype experiment is performed in the laboratory in which a transient step-response at the remote end of an energized conductor is measured.

  19. Evidence of fuels management and fire weather influencing fire severity in an extreme fire event

    Science.gov (United States)

    Lydersen, Jamie M; Collins, Brandon M.; Brooks, Matthew L.; Matchett, John R.; Shive, Kristen L.; Povak, Nicholas A.; Kane, Van R.; Smith, Douglas F.

    2017-01-01

    Following changes in vegetation structure and pattern, along with a changing climate, large wildfire incidence has increased in forests throughout the western U.S. Given this increase there is great interest in whether fuels treatments and previous wildfire can alter fire severity patterns in large wildfires. We assessed the relative influence of previous fuels treatments (including wildfire), fire weather, vegetation and water balance on fire severity in the Rim Fire of 2013. We did this at three different spatial scales to investigate whether the influences on fire severity changed across scales. Both fuels treatments and previous low to moderate severity wildfire reduced the prevalence of high severity fire. In general, areas without recent fuels treatments and areas that previously burned at high severity tended to have a greater proportion of high severity fire in the Rim Fire. Areas treated with prescribed fire, especially when combined with thinning, had the lowest proportions of high severity. Proportion of the landscape burned at high severity was most strongly influenced by fire weather and proportional area previously treated for fuels or burned by low to moderate severity wildfire. The proportion treated needed to effectively reduce the amount of high fire severity fire varied by spatial scale of analysis, with smaller spatial scales requiring a greater proportion treated to see an effect on fire severity. When moderate and high severity fire encountered a previously treated area, fire severity was significantly reduced in the treated area relative to the adjacent untreated area. Our results show that fuels treatments and low to moderate severity wildfire can reduce fire severity in a subsequent wildfire, even when burning under fire growth conditions. These results serve as further evidence that both fuels treatments and lower severity wildfire can increase forest resilience.

  20. Fires in Amazonia

    Science.gov (United States)

    Aragão, Luiz E. O. C.; Anderson, Liana O.; Lima, André; Arai, Egidio

    2016-11-01

    Fire has been used since the first humans arrived in Amazonia; however, it has recently become a widely used instrument for large-scale forest clearance. Patterns of fire incidence in the region have been exacerbated by recent drought events. Understanding temporal and spatial fire patterns as well as their consequences for forest structure, species composition, and the carbon cycle is critical for minimising global change impacts on Amazonian ecosystems and people. In this chapter, we provide an overview of the state of our knowledge on the spatial and temporal patterns of fire incidence in Amazonia, depicting the historical fire usage in the region, their relationship with land use and land cover, and their responses to climate seasonality and droughts. We subsequently focus on the impacts of fire, by quantifying the extent of burnt forests during major droughts and describing the main impacts on forest structure, composition, and carbon stocks. Finally, we present an overview of modelling initiatives for forecasting fire incidence in the region. We conclude by providing a comprehensive view of the processes that influence fire occurrence, potential feedbacks, and impacts in Amazonia. We also highlight how key areas within fire ecology must be improved for a better understanding of the long-term effect of fire on the Amazon forest 'biome'.

  1. Data Base On Cables And Connectors

    Science.gov (United States)

    Bowen, Arlen R.; Oliver, John D.

    1995-01-01

    Report describes Connector Adapter Cable Information Data Base (CONNAID) computer program, managing data base containing necessary information concerning electrical connectors, breakout boxes, adapter cables, backshells, and pertinent torque specifications for engineering project.

  2. Numerical Field Model Simulation of Full-Scale Fire Tests in a Closed Spherical/Cylindrical Vessel with Internal Ventilation

    Science.gov (United States)

    1988-09-01

    tional speed and massive storage capability, offer a researcher the option of computer modeling of fires. The systems of partial differen- tial...SMP123+SMPP12 i’.S 00101800 RI(I,JK I=-BUOY* DROGA /(RtI,J,K)*STRAIN) 00101900 ABRIPR:ABTURB+RI(I ,J,K )/PRT 00102000 IF(AF’.IPR .LT. 0.) GO TO b00 00102100

  3. Equalization of data transmission cable

    Science.gov (United States)

    Zobrist, G. W.

    1975-01-01

    The paper describes an equalization approach utilizing a simple RLC network which can obtain a maximum slope of -12dB/octave for reshaping the frequency characteristics of a data transmission cable, so that data may be generated and detected at the receiver. An experimental procedure for determining equalizer design specifications using distortion analysis is presented. It was found that for lengths of 16 PEV-L cable of up to 5 miles and data transmission rates of up to 1 Mbs, the equalization scheme proposed here is sufficient for generation of the data with acceptable error rates.

  4. Online Cable Tester and Rerouter

    Science.gov (United States)

    Lewis, Mark; Medelius, Pedro

    2012-01-01

    Hardware and algorithms have been developed to transfer electrical power and data connectivity safely, efficiently, and automatically from an identified damaged/defective wire in a cable to an alternate wire path. The combination of online cable testing capabilities, along with intelligent signal rerouting algorithms, allows the user to overcome the inherent difficulty of maintaining system integrity and configuration control, while autonomously rerouting signals and functions without introducing new failure modes. The incorporation of this capability will increase the reliability of systems by ensuring system availability during operations.

  5. How The Australian National University's emergency management and continuity plans responded to a large-scale fire.

    Science.gov (United States)

    Meehan, Bart

    2008-01-01

    On 18th January, 2003, one of the worst bushfires in the history of Australia hit the capital city, Canberra. By the time it was under control, four people were dead and more than 500 homes were destroyed. The fire also destroyed the Mount Stromlo campus of the Australian National University, the location of the Research School of Astronomy and Astrophysics. In response to the fires, the University initiated its emergency management strategy and business continuity plans. These allowed the School to recommence limited operations within two weeks of the disaster. This paper details a case study of the impact of the fire (in part using personal recollections of staff and students), and the emergency response implemented by the University. It describes the development of the University's emergency management strategy, with its emphasis on the key elements of clear chain of command and flexibility in developing an incident-specific response. The paper also provides an assessment of how the plan worked during an actual incident and some of the lessons learned, including the importance of the early response, managing the impact on people, media management, insurance and communications.

  6. Trenchless Replacement of Buried Cable Lines

    Directory of Open Access Journals (Sweden)

    Hans-Joachim Bayer

    2007-01-01

    Full Text Available An enormous amount of underground electricity and telecommunication cables have been worn over the time with technical defects or need capacity increases. Thus, new lines need to be installed. In urban areas, even in smaller communities and in natural reserves, open trenching is difficult and often not permitted.In response, new patented methods of trenchless cable replacement using the HDD equipment have been developed by the TT Group. The new technology is called “Wash-over-cable-replacement” and applies specially designed drill heads, cutting around the old cable string in various configurations (completely closed, U-shape or S-shape embracing, depending to the coating type of the old cable. This special cable replacement drill head separates the cable from the surrounding adhesive soil or the sand bedding by creating a very small annular space around the cable thus enabling the pulling or dragging out of the old cable section between the start and the exit pit. After the old cable has been loosened from the surrounding soil by means of the wash over process and pulled out, the new cable can be smoothly pulled into the void using the drill rods and embedding the new cable in a rich bed of Bentonite.The wash-over drill heads are slim and have inner and outer nozzles for Bentonite and bits to handle roots, pebbles, gravel and the like. These drill heads perform very quickly (up to 3 meters per minute to effectively wash over existing cables without damaging the cable coating and prepare the ground for a fast new laying of a new cable in the existing line. Network owners also benefit from the fact that new geodetic or topographic surveys and documentations of the new cable are not necessary. Only the documents, remarks, technical codes and existing geodetic data need to be updated.The paper will outline the technological background and include several practical job examples.

  7. Analysis of High Frequency Resonance in DFIG-based Offshore Wind Farm via Long Transmission Cable

    DEFF Research Database (Denmark)

    Song, Yipeng; Ebrahimzadeh, Esmaeil; Blaabjerg, Frede

    2018-01-01

    During the past two decades, the Doubly Fed Induction Generator (DFIG) based wind farm has been under rapid growth, and the increasing wind power penetration has been seen. Practically, these wind farms are connected to the three-phase AC grid through long transmission cable which can be modelled...... as several II units. The impedance of this cable cannot be neglected and requires careful investigation due to its long distance. As a result, the impedance interaction between the DFIG based wind farm and the long cable is inevitable, and may produce High Frequency Resonance (HFR) in the wind farm....... This paper discusses the HFR of the large scale DFIG based wind farm connected to the long cable. Several influencing factors, including 1) the length of the cable, 2) the output active power and 3) the rotor speed, are investigated. Simulation validations using MATLAB / Simulink have been conducted...

  8. North American Submarine Cable Association (NASCA) Submarine Cables

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data show the locations of in-service and out-of-service submarine cables that are owned by members of NASCA and located in U.S. territorial waters. More...

  9. Integrated Cable System Aging Management Guidance: Low-Voltage Cable

    Energy Technology Data Exchange (ETDEWEB)

    Denny, W M

    2003-01-02

    The document provides insights into common aging issues and symptoms and includes pictures and descriptions of deterioration that is observable. The report provides a rapid review of the important information necessary to assess the aging of the low-voltage cable system used in nuclear power plants.

  10. Fire and EMS Districts, These layers show the geographic area of each Fire and EMS responder contained in the County of Polk, Wisconsin., Published in 2006, 1:2400 (1in=200ft) scale, Polk County Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Fire and EMS Districts dataset current as of 2006. These layers show the geographic area of each Fire and EMS responder contained in the County of Polk, Wisconsin..

  11. Using Cable Television for Library Data Transmission.

    Science.gov (United States)

    Whitaker, Douglas A.

    1985-01-01

    Discusses information gained from a test of cable data circuits on a Geac bibliographic control system at the Wayne Oakland Library Federation (WOLF) (Michigan). Highlights include an introduction to cable, hardware profile, the WOLF experience, and key questions that will affect the future use of cable for data transmission. (EJS)

  12. Evidence of fuels management and fire weather influencing fire severity in an extreme fire event.

    Science.gov (United States)

    Lydersen, Jamie M; Collins, Brandon M; Brooks, Matthew L; Matchett, John R; Shive, Kristen L; Povak, Nicholas A; Kane, Van R; Smith, Douglas F

    2017-10-01

    Following changes in vegetation structure and pattern, along with a changing climate, large wildfire incidence has increased in forests throughout the western United States. Given this increase, there is great interest in whether fuels treatments and previous wildfire can alter fire severity patterns in large wildfires. We assessed the relative influence of previous fuels treatments (including wildfire), fire weather, vegetation, and water balance on fire-severity in the Rim Fire of 2013. We did this at three different spatial scales to investigate whether the influences on fire severity changed across scales. Both fuels treatments and previous low to moderate-severity wildfire reduced the prevalence of high-severity fire. In general, areas without recent fuels treatments and areas that previously burned at high severity tended to have a greater proportion of high-severity fire in the Rim Fire. Areas treated with prescribed fire, especially when combined with thinning, had the lowest proportions of high severity. The proportion of the landscape burned at high severity was most strongly influenced by fire weather and proportional area previously treated for fuels or burned by low to moderate severity wildfire. The proportion treated needed to effectively reduce the amount of high severity fire varied by spatial scale of analysis, with smaller spatial scales requiring a greater proportion treated to see an effect on fire severity. When moderate and high-severity fire encountered a previously treated area, fire severity was significantly reduced in the treated area relative to the adjacent untreated area. Our results show that fuels treatments and low to moderate-severity wildfire can reduce fire severity in a subsequent wildfire, even when burning under fire growth conditions. These results serve as further evidence that both fuels treatments and lower severity wildfire can increase forest resilience. © 2017 by the Ecological Society of America.

  13. Cable Television and Satellite Broadcasting

    Science.gov (United States)

    1990-05-31

    homes by the end teevision per week. However, accorigtthIne op that de a ay anthr 4 million hoesby - tohoe pendent Broadcast Authority’s (IBA...France to create a leisure desire to buy cable TV. park and a production studio for cartoons. 8 The Role of Public Service Providers In the Next Decade

  14. Power applications for superconducting cables

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Hansen, Steen; Jørgensen, Preben

    2000-01-01

    High temperature superconducting (HTS) cables for use in electric ac power systems are under development around the world today. There are two main constructions under development: the room temperature dielectric design and the cryogenic dielectric design. However, theoretical studies have shown...

  15. Impacts of an extreme cyclone event on landscape-scale savanna fire, productivity and greenhouse gas emissions

    Science.gov (United States)

    Hutley, L. B.; Evans, B. J.; Beringer, J.; Cook, G. D.; Maier, S. M.; Razon, E.

    2013-12-01

    North Australian tropical savanna accounts for 12% of the world’s total savanna land cover. Accordingly, understanding processes that govern carbon, water and energy exchange within this biome is critical to global carbon and water budgeting. Climate and disturbances drive ecosystem carbon dynamics. Savanna ecosystems of the coastal and sub-coastal of north Australia experience a unique combination of climatic extremes and are in a state of near constant disturbance from fire events (1 in 3 years), storms resulting in windthrow (1 in 5-10 years) and mega-cyclones (1 in 500-1000 years). Critically, these disturbances occur over large areas creating a spatial and temporal mosaic of carbon sources and sinks. We quantify the impact on gross primary productivity (GPP) and fire occurrence from a tropical mega-cyclone, tropical Cyclone Monica (TC Monica), which affected 10 400 km2 of savanna across north Australia, resulting in the mortality and severe structural damage to ˜140 million trees. We estimate a net carbon equivalent emission of 43 Tg of CO2-e using the moderate resolution imaging spectroradiometer (MODIS) GPP (MOD17A2) to quantify spatial and temporal patterns pre- and post-TC Monica. GPP was suppressed for four years after the event, equivalent to a loss of GPP of 0.5 Tg C over this period. On-ground fuel loads were estimated to potentially release 51.2 Mt CO2-e, equivalent to ˜10% of Australia’s accountable greenhouse gas emissions. We present a simple carbon balance to examine the relative importance of frequency versus impact for a number of key disturbance processes such as fire, termite consumption and intense but infrequent mega-cyclones. Our estimates suggested that fire and termite consumption had a larger impact on Net Biome Productivity than infrequent mega-cyclones. We demonstrate the importance of understanding how climate variability and disturbance impacts savanna dynamics in the context of the increasing interest in using savanna

  16. Ash transformation and deposit build-up during biomass suspension and grate firing: Full-scale experimental studies

    DEFF Research Database (Denmark)

    Shafique Bashir, Muhammad; Jensen, Peter Arendt; Frandsen, Flemming

    2012-01-01

    An attractive option for reducing the net CO2 emissions is to substitute coal with biomass in large power plant boilers. However, the presence of chlorine (Cl) and alkali metals (K, Na) in biomassmay induce large operational problems due to ash deposit formation on the superheater tubes. The aim...... on similar levels. This was observed even though the concentration of fly ash in the flue gas was significantly higher during straw suspension firing. The influence of co-combustion of wood with straw on deposit formation rate, probe heat uptake and deposit characteristicswas also investigated during...

  17. Suspension-Firing of Biomass:Part 1, Full-Scale Measurements of Ash Deposit Build-up

    OpenAIRE

    Bashir, Muhammad Shafique; Jensen, Peter Arendt; Frandsen, Flemming; Wedel, Stig; Dam-Johansen, Kim; Wadenbäck, Johan; Pedersen, Søren Thaaning

    2012-01-01

    This paper is Part 1 in a series of two describing probe measurements of deposit build-up and removal (shedding) in a 350 MWth suspension boiler, firing straw and wood. The influence of fuel type (straw share in wood), probe exposure time, probe surface temperature (500, 550, and 600 °C), and flue gas temperature (600–1050 °C) on ash deposit formation rate has been investigated. Investigations of deposit formation rate were made by use of an advanced online deposit probe that allowed nearly c...

  18. Experimental-theoretical approach to carbon monoxide density calculation at the incipient stage of the fire indoors

    Science.gov (United States)

    Puzach, S. V.; Suleykin, E. V.; Akperov, R. G.; Nguyen, T. D.

    2017-11-01

    A new experimental-theoretical approach to the toxic gases concentrations assessment in case of fire indoors is offered. The analytical formulas for calculation of CO average volume density are received. These formulas do not contain the geometrical sizes of the room and surfaces dimensions of combustible materials and, therefore, are valid under conditions of as a small-scale fire as a large-scale fire. A small-scale experimental installation for modeling fire thermal and gas dynamics in the closed or open thermodynamic system has been designed. The results of the experiments on determining dependencies of CO average volume density from average volume temperature and oxygen average volume density as well as dependencies of specific coefficients of CO emission and specific mass rates of the combustible material gasification from the time of tests during the burning of wood, transformer oil and PVC cables shield are presented. The results of numerical experiments on CO density calculation in small and large scale rooms using the proposed analytical solutions, integral, zone and field models for calculation of fire thermal and gas dynamics are presented. The comparison with the experimental data obtained by the authors and given in the literature has been performed. It is shown that CO density calculation in the full-scale room at the incipient stage of the fire can be carried out taking into account only the experimental dependences of CO from temperature or O2 density, that have been obtained from small-scale experiments. Therefore the solution of the equation of carbon monoxide mass conservation law is not necessary.

  19. Optimisation of Offshore Wind Farm Cable Connection Layout Considering Levelised Production Cost Using Dynamic Minimum Spanning Tree Algorithm

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Chen, Cong

    2016-01-01

    The approach in this paper hads been developed to optimize the cable connection layout of large scale offshore wind farms. The objective is to minimize the Levelised Production Cost (LPC) og an offshore wind farm by optimizing the cable connection configuration. Based on the minimum spanning tree...... (MST) algorithm, an improved algorithm, the Dynamic Minimum Spanning Tree (DMST) algorithm is proposed. The current carrying capacity of the cable is considered to be the main constraint and the cable sectional area is changed dynamically. An irregular shaped wind farm is chosen as the studie case...

  20. Fire safety

    Science.gov (United States)

    Robert H. White; Mark A. Dietenberger

    1999-01-01

    Fire safety is an important concern in all types of construction. The high level of national concern for fire safety is reflected in limitations and design requirements in building codes. These code requirements are discussed in the context of fire safety design and evaluation in the initial section of this chapter. Since basic data on fire behavior of wood products...

  1. Offshore Cable Installation - Lillgrund. Lillgrund Pilot Project

    Energy Technology Data Exchange (ETDEWEB)

    Unosson, Oscar (Vattenfall Vindkraft AB, Stockholm (Sweden))

    2009-01-15

    This report describes the installation method and the experiences gained during the installation of the submarine cables for the offshore wind farm at Lillgrund. The wind farm consists of 48 wind turbines and is expected to produce 0.33 TWh annually. Different aspects of the installation, such as techniques, co-operation between the installation teams, weather conditions and regulatory and environmental issues are described in this report. In addition, recommendations and guidelines are provided, which hopefully can be utilised in future offshore wind projects. The trenches, in which the submarine cables were laid, were excavated weeks before the cable laying. This installation technique proved to be successful for the laying of the inter array cables. The export cable, however, was laid into position with difficulty. The main reason why the laying of the export cable proved more challenging was due to practical difficulties connected with the barge entrusted with the cable laying, Nautilus Maxi. The barge ran aground a number of times and it had difficulties with the thrusters, which made it impossible to manoeuvre. When laying the inter array cables, the method specification was closely followed, and the laying of the cables was executed successfully. The knowledge and experience gained from the offshore cable installation in Lillgrund is essential when writing technical specifications for new wind plant projects. It is recommended to avoid offshore cable installation work in winter seasons. That will lower the chances of dealing with bad weather and, in turn, will reduce the risks

  2. Parallel monostrand stay cable bending fatigue

    DEFF Research Database (Denmark)

    Winkler, Jan Pawel

    of a cable stayed bridge. Characterization of a bridge monitoring data is shown and a generic method for the analysis of a cable fatigue in cable supported bridge structure is proposed. With this research, one of the most basic oversights in the lifetime assessment of cablesupported structures, namely......This dissertation investigates the bending fatigue response of high-strength steel monostrands and multistrand stay cables to cyclic transverse deformations. Increasing bridge stock numbers and a push for longer cable-supported span lengths have led to an increased number of reported incidents...... of damage and replacement of bridge stay cables due to wind and traffic-induced fatigue. The understanding of fatigue mechanisms in most steel structures is well established. However, in the case of cables composed of steel strands, many important aspects related with bending fatigue remain to be clarified...

  3. Distribution of persistent organic pollutants, polycyclic aromatic hydrocarbons and trace elements in soil and vegetation following a large scale landfill fire in northern Greece.

    Science.gov (United States)

    Chrysikou, Loukia; Gemenetzis, Panagiotis; Kouras, Athanasios; Manoli, Evangelia; Terzi, Eleni; Samara, Constantini

    2008-02-01

    Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), including hexaclorocyclohexanes (HCHs) and DDTs, as well as trace elements were determined in soil and vegetation samples collected from the surrounding area of the landfill "Tagarades", the biggest in northern Greece, following a large scale fire involving approximately 50,000 tons of municipal waste. High concentrations of total PAHs, PCBs and heavy metals were found inside the landfill (1475 microg kg(-1) dw, 399 microg kg(-1) dw and 29.8 mg kg(-1) dw, respectively), whereas concentrations in the surrounding soils were by far lower ranging between 11.2-28.1 microg kg(-1) dw for PAHs, 4.02-11.2 microg kg(-1) dw for PCBs and 575-1207 mg kg(-1) dw for heavy metals. The distribution of HCHs and DDTs were quite different since certain soils exhibited equal or higher concentrations than the landfill. In vegetation, the concentrations of PAHs, PCBs, HCHs and DDTs ranged from 14.1-34.7, 3.64-25.9, 1.41-32.1 and 0.61-4.03 microg kg(-1) dw, respectively, while those of heavy metals from 81 to 159 mg kg(-1) dw. The results of the study indicated soil and vegetation pollution levels in the surroundings of the landfill comparable to those reported for other Greek locations. The impact from the landfill fire was not evident partially due to the presence of recent and past inputs from other activities (agriculture, vehicular transport, earlier landfill fires).

  4. Energy release from pit fires for producing a fire model. Natural-scale analysis of energy release from pit fires for the purpose of establishing a fire model. Final report; Energiefreisetzung von Grubenbraenden zur Erstellung eines Brandmodell. Untersuchung ueber die Energiefreisetzung von Grubenbraenden im natuerlichen Massstab zur Erstellung eines Brandmodells. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Holke, K.; Michelis, J.

    1996-12-31

    In the context of the research project, measurements were made regarding the energy release in pit fires. The heat flow in fires with standard wood fire objects and in fires on conveyor belts in underground fire sections of the DMT Tremonia experimental pit was measured for this purpose. It was found that the distribution of the mean total heat flow in the roadway crossection depended on the geometric arrangement of the fire object. The belt fire tests carried out have shown that the heat flow depended on the burning behaviour of the belts and with increasing flame propagation on the conveyor belt, the mean heat flow increased. Further, the temperature effects after wood and conveyor belt fires were simulated with the modified `MFIRE` simulation program and were compared with the corresponding experimental results. (orig./MSK) [Deutsch] Im Rahmen des Untersuchungsvorhabens wurden Messungen bezueglich der Energiefreisetzung bei Grubenbraenden durchgefuehrt. Hierzu wurde der Waermefluss bei Braenden mit Standardholzbrandobjekten und bei Foerdergurtbraenden in den untertaegigen Brandstrecken der DMT-Versuchsgrube Tremonia gemessen. Es zeigte sich, dass die Verteilung des mittleren Gesamtwaermeflusses im Streckenquerschnitt von der geometrischen Anordnung des Brandobjektes abhing. Die durchgefuehrten Gurtbrandversuche haben ergeben, dass der Waermefluss vom Brandverhalten der Gurte abhing und mit zunehmender Flammenausbreitung am Foerdergurt der mittlere Waermefluss zunahm. Weiterhin wurden mit dem modifizierten Simulationsprogramm `MFIRE` die Temperaturauswirkungen hinter Holz- und Foerdergurtbraenden simuliert und mit den entsprechenden experimentellen Ergebnissen verglichen. (orig./MSK)

  5. Use of prescribed fire to reduce wildfire potential

    Science.gov (United States)

    Robert E. Martin; J. Boone Kauffman

    1989-01-01

    Fires were a part of our wildlands prehistorically. Prescribed burning reduces fire hazard and potential fire behavior primarily by reducing fuel quantity and continuity. Fuel continuity should be considered on the micro scale within stands, the mid-scale among, and the macro-scale among watersheds or entire forests. Prescribed fire is only one of the tools which can...

  6. Estimation of Scale Deposition in the Water Walls of an Operating Indian Coal Fired Boiler: Predictive Modeling Approach Using Artificial Neural Networks

    Science.gov (United States)

    Kumari, Amrita; Das, Suchandan Kumar; Srivastava, Prem Kumar

    2016-04-01

    Application of computational intelligence for predicting industrial processes has been in extensive use in various industrial sectors including power sector industry. An ANN model using multi-layer perceptron philosophy has been proposed in this paper to predict the deposition behaviors of oxide scale on waterwall tubes of a coal fired boiler. The input parameters comprises of boiler water chemistry and associated operating parameters, such as, pH, alkalinity, total dissolved solids, specific conductivity, iron and dissolved oxygen concentration of the feed water and local heat flux on boiler tube. An efficient gradient based network optimization algorithm has been employed to minimize neural predictions errors. Effects of heat flux, iron content, pH and the concentrations of total dissolved solids in feed water and other operating variables on the scale deposition behavior have been studied. It has been observed that heat flux, iron content and pH of the feed water have a relatively prime influence on the rate of oxide scale deposition in water walls of an Indian boiler. Reasonably good agreement between ANN model predictions and the measured values of oxide scale deposition rate has been observed which is corroborated by the regression fit between these values.

  7. ESTIMATION OF INDUCED CURRENTS IN THE SHIELDS OF ELECTRICAL POWER CABLES WITH XLPE INSULATION

    Directory of Open Access Journals (Sweden)

    I. V. Oleksyuk

    2015-01-01

    Full Text Available Electrical power cables with Cross-Linked Polyethylene Insulation (XLPE-insulation are currently utilized in projects of the electric-power supply systems of modern facilities. However, the higher costs, the incomplete design, installation and maintenance normativetechnical basis as well as certain constructional features of the XLPE-insulated cable lines hinder their large-scale implementation.The cables with XLPE insulation are mostly produced in a single-conductor core version being provided with a composite copper shield whose cross-section may vary while the electric conductor cross-section remains uniform. Earthing the cable shields on both sides causes the flow of electricity in them. The course of operational service of the XLPE-insulated cable lines revealed the following fact – the currents induced in the cable shields can run up to the levels commeasurable with those in the conductor-cores themselves. That, in its turn, leads to electrical safety-level reduction, cable lines failure, and economic losses. The currents induced in the shields may occur both in symmetric (normal and emergency and asymmetric operating modes of the power grid with values of the induced currents reaching 80 % of the conducting core currents. Many factors affect the level of the current induced in the shield: the midpoint conductor modes, the values of the core longitudinal currents in the normal and emergency operating modes, failure mode, the cross-section area of the shield, the cables mutual disposition, and the distance between them.The paper claims experimental existence conformation of the cable-shield current induced by that in the conductor-core and demonstrates its measured value. The author establishes that induction of dangerous currents in the cable shields demands elaboration of measures on reducing their level.

  8. Large-Scale Mercury Control Technology Testing for Lignite-Fired Utilities - Oxidation Systems for Wet FGD

    Energy Technology Data Exchange (ETDEWEB)

    Steven A. Benson; Michael J. Holmes; Donald P. McCollor; Jill M. Mackenzie; Charlene R. Crocker; Lingbu Kong; Kevin C. Galbreath

    2007-03-31

    Mercury (Hg) control technologies were evaluated at Minnkota Power Cooperative's Milton R. Young (MRY) Station Unit 2, a 450-MW lignite-fired cyclone unit near Center, North Dakota, and TXU Energy's Monticello Steam Electric Station (MoSES) Unit 3, a 793-MW lignite--Powder River Basin (PRB) subbituminous coal-fired unit near Mt. Pleasant, Texas. A cold-side electrostatic precipitator (ESP) and wet flue gas desulfurization (FGD) scrubber are used at MRY and MoSES for controlling particulate and sulfur dioxide (SO{sub 2}) emissions, respectively. Several approaches for significantly and cost-effectively oxidizing elemental mercury (Hg{sup 0}) in lignite combustion flue gases, followed by capture in an ESP and/or FGD scrubber were evaluated. The project team involved in performing the technical aspects of the project included Babcock & Wilcox, the Energy & Environmental Research Center (EERC), the Electric Power Research Institute, and URS Corporation. Calcium bromide (CaBr{sub 2}), calcium chloride (CaCl{sub 2}), magnesium chloride (MgCl{sub 2}), and a proprietary sorbent enhancement additive (SEA), hereafter referred to as SEA2, were added to the lignite feeds to enhance Hg capture in the ESP and/or wet FGD. In addition, powdered activated carbon (PAC) was injected upstream of the ESP at MRY Unit 2. The work involved establishing Hg concentrations and removal rates across existing ESP and FGD units, determining costs associated with a given Hg removal efficiency, quantifying the balance-of-plant impacts of the control technologies, and facilitating technology commercialization. The primary project goal was to achieve ESP-FGD Hg removal efficiencies of {ge}55% at MRY and MoSES for about a month.

  9. Tubing and cable cutting tool

    Science.gov (United States)

    Mcsmith, D. D.; Richardson, J. I. (Inventor)

    1984-01-01

    A hand held hydraulic cutting tool was developed which is particularly useful in deactivating ejection seats in military aircraft rescue operations. The tool consists primarily of a hydraulic system composed of a fluid reservoir, a pumping piston, and an actuator piston. Mechanical cutting jaws are attached to the actuator piston rod. The hydraulic system is controlled by a pump handle. As the pump handle is operated the actuator piston rod is forced outward and thus the cutting jaws are forced together. The frame of the device is a flexible metal tubing which permits easy positioning of the tool cutting jaws in remote and normally inaccessible locations. Bifurcated cutting edges ensure removal of a section of the tubing or cable to thereby reduce the possibility of accidental reactivation of the tubing or cable being severed.

  10. Slipstream pilot-scale demonstration of a novel amine-based post-combustion technology for carbon dioxide capture from coal-fired power plant flue gas

    Energy Technology Data Exchange (ETDEWEB)

    Krishnamurthy, Krish R. [Linde LLC, Murray Hill, NJ (United States)

    2017-02-03

    Post-combustion CO2 capture (PCC) technology offers flexibility to treat the flue gas from both existing and new coal-fired power plants and can be applied to treat all or a portion of the flue gas. Solvent-based technologies are today the leading option for PCC from commercial coal-fired power plants as they have been applied in large-scale in other applications. Linde and BASF have been working together to develop and further improve a PCC process incorporating BASF’s novel aqueous amine-based solvent technology. This technology offers significant benefits compared to other solvent-based processes as it aims to reduce the regeneration energy requirements using novel solvents that are very stable under the coal-fired power plant feed gas conditions. BASF has developed the desired solvent based on the evaluation of a large number of candidates. In addition, long-term small pilot-scale testing of the BASF solvent has been performed on a lignite-fired flue gas. In coordination with BASF, Linde has evaluated a number of options for capital cost reduction in large engineered systems for solvent-based PCC technology. This report provides a summary of the work performed and results from a project supported by the US DOE (DE-FE0007453) for the pilot-scale demonstration of a Linde-BASF PCC technology using coal-fired power plant flue gas at a 1-1.5 MWe scale in Wilsonville, AL at the National Carbon Capture Center (NCCC). Following a project kick-off meeting in November 2011 and the conclusion of pilot plant design and engineering in February 2013, mechanical completion of the pilot plant was achieved in July 2014, and final commissioning activities were completed to enable start-up of operations in January 2015. Parametric tests were performed from January to December 2015 to determine optimal test conditions and evaluate process performance over a variety of operation parameters. A long-duration 1500-hour continuous test campaign was performed from May to

  11. Fire water

    Energy Technology Data Exchange (ETDEWEB)

    Thorpe, K. [Lawrence Webster Forrest Ltd. (United Kingdom)

    2001-01-01

    The article focuses on the value of water in fighting fires and discusses why refineries should identify water supply and distribution in contingency planning against fire. In the event of a fire, water will be required for (i) extinguishing the fire; (ii) protection of equipment and (iii) confinement of the fire. The thought process for identifying the water demand in the event of a fire is outlined. Tables give data on (a) water rates for cooling storage tanks; (b) water rates for cooling process units (c) guide to water requirements for various sizes of process units and (d) pumping requirements.

  12. Initial tension loss in cerclage cables.

    Science.gov (United States)

    Ménard, Jérémie; Émard, Maxime; Canet, Fanny; Brailovski, Vladimir; Petit, Yvan; Laflamme, George Y

    2013-10-01

    Cerclage cables, frequently used in the management of fractures and osteotomies, are associated with a high failure rate and significant loosening during surgery. This study compared the capacity to maintain tension of different types of orthopaedic cable systems. Multifilament Cobalt-Chrome (CoCr) cables with four different crimp/clamp devices (DePuy, Stryker, Zimmer and Smith&Nephew) and one non-metallic Nylon (Ny) cable from Kinamed were instrumented with a load cell to measure tension during insertion. Significant tension loss was observed with crimping for all cables (Ptensioner led to an additional unexpected tension loss (CoCr-DePuy: 18%, CoCr-Stryker: 29%, CoCr-Smith&Nephew: 33%, Ny: 46%, and CoCr-Zimmer: 52%). The simple CoCr (DePuy) cable system outperformed the more sophisticated locking devices due to its significantly better ability to prevent tension loss. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Field application of a cable NDT system for cable-stayed bridge using MFL sensors integrated

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ju Won; Choi, Jun Sung; Park, Seung Hee [Sungkyunkwan University, Seoul (Korea, Republic of); Lee, Eun Chan [Korea Maintance Co., Ltd., Seoul (Korea, Republic of)

    2014-02-15

    In this study, an automated cable non-destructive testing(NDT) system was developed to monitor the steel cables that are a core component of cable-stayed bridges. The magnetic flux leakage(MFL) method, which is suitable for ferromagnetic continuum structures and has been verified in previous studies, was applied to the cable inspection. A multi-channel MFL sensor head was fabricated using hall sensors and permanent magnets. A wheel-based cable climbing robot was fabricated to improve the accessibility to the cables, and operating software was developed to monitor the MFL-based NDT research and control the climbing robot. Remote data transmission and robot control were realized by applying wireless LAN communication. Finally, the developed element techniques were integrated into an MFL-based cable NDT system, and the field applicability of this system was verified through a field test at Seohae Bridge, which is a typical cable-stayed bridge currently in operation.

  14. Dynamic Behaviour of Different Types of Cable-Stayed Bridges Due to Earthquake Loads

    Directory of Open Access Journals (Sweden)

    Alireza Mirza Goltabar Roshan

    2016-12-01

    Full Text Available Construction of large-scale structures has been considered as one of the human's main achievements.  With their suitable view and high economical aspects, High-strength steel cables have been developed for analysis and erection of cable-stayed bridges in light of high speed development in computer technology. This type of bridges, while providing different behavior due to cable flexibility, has been recognized as one of the most practical choices for mid to large span bridges. This paper studies the non-linear dynamic behavior of cable bridges and the effect of some parameters (such as cable arrangement and shape of pylon on them. For this purpose, CSI Bridge software with the direct integration method of dynamic analysis has been used and the behavior of structure under different earthquake components has been analyzed for various conditions of cable arrangements and pylon shapes. Results indicate that the most suitable behavior would be for cable bridges with H-shape pylons arranged in series and also with A-shape pylons in radial arrangement.

  15. Climatic and weather factors affecting fire occurrence and behavior

    Science.gov (United States)

    Randall P. Benson; John O. Roads; David R. Weise

    2009-01-01

    Weather and climate have a profound influence on wildland fire ignition potential, fire behavior, and fire severity. Local weather and climate are affected by large-scale patterns of winds over the hemispheres that predispose wildland fuels to fire. The characteristics of wildland fuels, especially the moisture content, ultimately determine fire behavior and the impact...

  16. Ecological fire use for ecological fire management: Managing large wildfires by design

    Science.gov (United States)

    Timothy Ingalsbee

    2015-01-01

    Past fire exclusion policies and fire suppression actions have led to a historic "fire deficit" on public wildlands. These sociocultural actions have led to unprecedented environmental changes that have created conditions conducive to more frequent large-scale wildfires. Politicians, the newsmedia, and agency officials portray large wildland fires as...

  17. Post-fire regeneration across a fire severity gradient in the southern Cascades

    Science.gov (United States)

    Justin Crotteau; Morgan Varner; Martin Ritchie

    2012-01-01

    Large scale, high-severity fires are increasing in the western United States. Despite this trend, there have been few studies investigating post-fire tree regeneration. We established a study in the footprint of the 2000 Storrie Fire, a 23,000 ha wildfire that occurred in northern California, USA. We used a stratified sampling design to quantify post-fire vegetation...

  18. Fire Stations

    Data.gov (United States)

    Department of Homeland Security — Fire Stations in the United States Any location where fire fighters are stationed or based out of, or where equipment that such personnel use in carrying out their...

  19. Managing cable thermal stress through predictive ratings

    OpenAIRE

    Huang, R.; Pilgrim, J.A.; Lewin, P.L.; Scott, D.; Morrice, D.

    2015-01-01

    The majority of high voltage cables are sized and operated by a continuous current rating which is based on the worst-case assumptions. However, the load on the cables themselves may vary significantly depending upon the time and season. In this paper, a dynamic thermal model for a cable in air installation is built using the finite difference method. The real-time load current and ambient conditions are accessible to allow improved cable modelling. This model is then used to support the rati...

  20. MARS: a cabled observatory testbed in Monterey Bay

    Science.gov (United States)

    McNutt, M.; Massion, G.; Raybould, K.; Bellingham, J.; Paull, C.

    2003-04-01

    With funding from the U.S. National Science Foundation and the David and Lucile Packard Foundation, the Monterey Bay Aquarium Research Institute (MBARI) will be installing a deep-sea observatory in Monterey Bay, California, that will serve as a test bed for a future regional-scale cabled observatory. Monterey Bay offers a variety of active processes for scientific inquiry, including a very productive zone of ocean upwelling, a seismically active strand of the San Andreas fault system, cold seeps, and a very dynamic submarine canyon. The MARS (Monterey Accelerated Research System) cable will extend more than 60 km offshore to an instrument node at a depth of approximately 1.2 km. Extension cords can be run by remotely operated vehicles (ROVs) from the cable node up to several kilometers away in order to provide greater flexibility in siting instruments. The observatory will be serviced using ROVs and will serve as a test bed for developing new sensors, instruments systems, experiment protocols, and mobile platforms for which submarine cables will provide power and two-way communications. In addition to serving as a test bed for instrumentation and platforms, the MARS project will demonstrate models for how to operate, service, and manage a community facility of this sort. In cooperation with our outreach partner, the Monterey Bay Aquarium, we will be examining ways to exploit the full potential of deep-sea observatories for student education and public information. We will also be preparing a proposal to the Integrated Ocean Drilling Program (IODP) to provide a nearby drill hole for connecting bore-hole experiments to the MARS cable, thereby accelerating the development of new tools for probing Earth beneath the oceans.

  1. Heat-Transfer Tests of 20-Millimeter Projectiles at a Mach Number of 5 with an Analysis by Unsteady Scaling Laws to Predict Component Temperature Rises after Firing for Various Free-Flight Conditions

    Science.gov (United States)

    Trimpi, Robert L.; Gallagher, James G.; Jones, Robert A.

    1961-01-01

    The temperature time history of various components of a 20-millimeter projectile was obtained by transient heating tests in a Mach number 5 blowdown tunnel. An unsteady scaling law is derived and used to predict the temperature time histories after firing in flight at various Mach numbers and altitudes.

  2. Designing and Implementation a Lab Testing Method for Power Cables Insulation Resistance According with STAS 10411-89, SR EN ISO/CEI/17025/2005

    Science.gov (United States)

    Dobra, R.; Pasculescu, D.; Marc, G.; Risteiu, M.; Antonov, A.

    2017-06-01

    Insulation resistance measurement is one of the most important tests required by standards and regulations in terms of electrical safety. Why these tests are is to prevent possible accidents caused by electric shock, damage to equipment or outbreak of fire in normal operating conditions of electrical cables. The insulation resistance experiment refers to the testing of electrical cable insulation, which has a measured resistance that must be below the imposed regulations. Using a microcontroller system data regarding the insulation resistance of the power cables is acquired and with SCADA software the test results are displayed.

  3. US Fire Administration Fire Statistics

    Data.gov (United States)

    Department of Homeland Security — The U.S. Fire Administration collects data from a variety of sources to provide information and analyses on the status and scope of the fire problem in the United...

  4. Place mapping and the role of spatial scale in understanding landowner views of fire and fuels management

    Science.gov (United States)

    Michael A. Cacciapaglia; Laurie Yung; Michael E. Patterson

    2011-01-01

    Place mapping is emerging as a way to understand the spatial components of people's relationships with particular locations and how these relate to support for management proposals. But despite the spatial focus of place mapping, scale is rarely explicitly examined in such exercises. This is particularly problematic since scalar definitions and configurations have...

  5. Large Pilot Scale Testing of Linde/BASF Post-Combustion CO2 Capture Technology at the Abbott Coal-Fired Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, Kevin C. [University of Illinois, Champaign, IL (United States)

    2017-08-18

    The work summarized in this report is the first step towards a project that will re-train and create jobs for personnel in the coal industry and continue regional economic development to benefit regions impacted by previous downturns. The larger project is aimed at capturing ~300 tons/day (272 metric tonnes/day) CO2 at a 90% capture rate from existing coal- fired boilers at the Abbott Power Plant on the campus of University of Illinois (UI). It will employ the Linde-BASF novel amine-based advanced CO2 capture technology, which has already shown the potential to be cost-effective, energy efficient and compact at the 0.5-1.5 MWe pilot scales. The overall objective of the project is to design and install a scaled-up system of nominal 15 MWe size, integrate it with the Abbott Power Plant flue gas, steam and other utility systems, and demonstrate the viability of continuous operation under realistic conditions with high efficiency and capacity. The project will also begin to build a workforce that understands how to operate and maintain the capture plants by including students from regional community colleges and universities in the operation and evaluation of the capture system. This project will also lay the groundwork for follow-on projects that pilot utilization of the captured CO2 from coal-fired power plants. The net impact will be to demonstrate a replicable means to (1) use a standardized procedure to evaluate power plants for their ability to be retrofitted with a pilot capture unit; (2) design and construct reliable capture systems based on the Linde-BASF technology; (3) operate and maintain these systems; (4) implement training programs with local community colleges and universities to establish a workforce to operate and maintain the systems; and (5) prepare to evaluate at the large pilot scale level various methods to utilize the resulting captured CO2. Towards the larger project goal, the UI-led team, together

  6. Vibration mitigation of a bridge cable using a nonlinear energy sink: design and experiment

    Directory of Open Access Journals (Sweden)

    Weiss Mathieu

    2015-01-01

    Full Text Available This work deals with the design and experiment of a cubic nonlinear energy sink (NES for horizontal vibration mitigation of a bridge cable. Modal analysis of horizontal linear modes of the cable is experimentally performed using accelerometers and displacement sensors. A theoretical simplified 2-dof model of the coupled cable-NES system is used to analytically design the NES by mean of multi-time scale systems behaviours and detection its invariant manifold, equilibrium and singular points which stand for periodic and strongly modulated regimes, respectively. Numerical integration is used to confirm the efficiency of the designed NES for the system under step release excitation. Then, the prototype system is built using geometrical cubic nonlinearity as the potential of the NES. Efficiency of the prototype system for mitigation of horizontal vibrations of the cable under for step release and forced excitations is experimentally demonstrated.

  7. Impedance-Based Cable Force Monitoring in Tendon-Anchorage Using Portable PZT-Interface Technique

    Directory of Open Access Journals (Sweden)

    Thanh-Canh Huynh

    2014-01-01

    Full Text Available In this paper, a portable PZT interface for tension force monitoring in the cable-anchorage subsystem is developed. Firstly, the theoretical background of the impedance-based method is presented. A few damage evaluation approaches are outlined to quantify the variation of impedance signatures. Secondly, a portable PZT interface is designed to monitor impedance signatures from the cable-anchorage subsystem. One degree-of-freedom analytical model of the PZT interface is established to explain how to represent the loss of cable force from the change in the electromechanical impedance of the PZT interface as well as reducing the sensitive frequency band by implementing the interface device. Finally, the applicability of the proposed PZT-interface technique is experimentally evaluated for cable force-loss monitoring in a lab-scaled test structure.

  8. A taxonomic framework for cable bacteria and proposal of the candidate genera Electrothrix and Electronema

    DEFF Research Database (Denmark)

    Trojan, Daniela; Schreiber, Lars; Bjerg, Jesper Tataru

    2016-01-01

    Cable bacteria are long, multicellular filaments that can conduct electric currents over centimeter-scale distances. All cable bacteria identified to date belong to the deltaproteobacterial family Desulfobulbaceae and have not been isolated in pure culture yet. Their taxonomic delineation and exact......RNA gene sequences of 16 individual cable bacteria filaments from freshwater, salt marsh, and marine sites of four geographic locations are presented. These sequences formed a distinct, monophyletic sister clade to the genus Desulfobulbus and could be divided into six coherent, species-level clusters......, arranged as two genus-level groups. The same grouping was retrieved by phylogenetic analysis of full or partial dsrAB genes encoding the dissimilatory sulfite reductase. Based on these results, it is proposed to accommodate cable bacteria within two novel candidate genera: the mostly marine “Candidatus...

  9. POTS to broadband ... cable modems.

    Science.gov (United States)

    Kabachinski, Jeff

    2003-01-01

    There have been 3 columns talking about broadband communications and now at the very end when it's time to compare using a telco or cableco, I'm asking does it really matter? So what if I can actually get the whole 30 Mbps with a cable network when the website I'm connecting to is running on an ISDN line at 128 Kbps? Broadband offers a lot more bandwidth than the connections many Internet servers have today. Except for the biggest websites, many servers connect to the Internet with a switched 56-Kbps, ISDN, or fractional T1 line. Even with the big websites, my home network only runs a 10 Mbps Ethernet connection to my cable modem. Maybe it doesn't matter that the cable lines are shared or that I can only get 8 Mbps from an ADSL line. Maybe the ISP that I use has a T1 line connection to the Internet so my new ADSL modem has a fatter pipe than my provider! (See table 1). It all makes me wonder what's in store for us in the future. PC technology has increased exponentially in the last 10 years with super fast processor speeds, hard disks of hundreds of gigabytes, and amazing video and audio. Internet connection speeds have failed to keep the same pace. Instead of hundreds of times better or faster--modem speeds are barely 10 times faster. Broadband connections offer some additional speed but still not comparable growth as broadband connections are still in their infancy. Rather than trying to make use of existing communication paths, maybe we need a massive infrastructure makeover of something new. How about national wireless access points so we can connect anywhere, anytime? To use the latest and fastest wireless technology you will simply need to buy another $9.95 WLAN card or download the latest super slick WLAN compression/encryption software. Perhaps it is time for a massive infra-restructuring. Consider the past massive infrastructure efforts. The telcos needed to put in their wiring infrastructure starting in the 1870s before telephones were useful to the

  10. Material problems related to large scale firing of biomass. Steam oxidation of TP 347H FG and X20

    Energy Technology Data Exchange (ETDEWEB)

    Noergaard Hansson, A.

    2009-07-01

    TP 347 H and X20 is often used as construction material in biomass-fired boilers. The corrosion rate of the alloys is affected by the metal temperature. In this project, the oxidation behaviour of TP 347H FG and X20 is studied by field-testing, laboratory exposures, and thermodynamic/kinetic modelling. The long term oxidation behaviour of TP 347H FG at ultra supercritical steam conditions was assessed by exposing the steel in 4 test superheater loops in a coal-fired power plant. The steel was exposed for 7720, 22985, 29588, and 57554 h at metal temperatures between 499 and 650 deg. C. In the laboratory furnace, the oxidation behaviour of TP 347H FG, TP 347H CG, and X20 was studied in water vapour containing environments (8 or 46%) in the temperature range 500-700 deg. C. Air, Ar and Ar+7% H{sub 2} were used as carrier gas. The microstructure of the oxide layer and the subjacent alloy was investigated with X-ray diffraction (XRD), reflective light microscopy (RLM), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), and transmission electron microscopy (TEM) equipped with electron diffraction (ED) and EDS. Double-layered oxides developed during steam oxidation of TP 347H FG both during field-testing and during laboratory exposures. TEM investigation suggested that the interior of the alloy grain was oxidised internally, forming particles of metallic Ni/Fe and Fe-Cr spinel. A FeCr{sub 2}O{sub 4} layer developed along the former alloy grain boundaries. Cr{sub 2}O{sub 3} developed in between this layer and the alloy during field-testing, and its formation was promoted by higher temperature. The morphology of the inner layer for the samples oxidised below and above approx. 585 deg. C looked very different in SEM (field-testing). It is suggested that more Cr is incorporated into the oxide layer at higher temperature, gradually transforming the morphology of the inner oxide layer. The alloy beneath the oxide layer was depleted in Cr

  11. Modified cable equation incorporating transverse polarization of neuronal membranes for accurate coupling of electric fields.

    Science.gov (United States)

    Wang, Boshuo; Aberra, Aman S; Grill, Warren M; Peterchev, Angel V

    2018-01-24

    We present a theory and computational methods to incorporate transverse polarization of neuronal membranes into the cable equation to account for the secondary electric field generated by the membrane in response to transverse electric fields. The effect of transverse polarization on nonlinear neuronal activation thresholds is quantified and discussed in the context of previous studies using linear membrane models. The response of neuronal membranes to applied electric fields is derived under two time scales and a unified solution of transverse polarization is given for spherical and cylindrical cell geometries. The solution is incorporated into the cable equation re-derived using an asymptotic model that separates the longitudinal and transverse dimensions. Two numerical methods are proposed to implement the modified cable equation. Several common neural stimulation scenarios are tested using two nonlinear membrane models to compare thresholds of the conventional and modified cable equations. The implementations of the modified cable equation incorporating transverse polarization are validated against previous results in the literature. The test cases show that transverse polarization has limited effect on activation thresholds. The transverse field only affects thresholds of unmyelinated axons for short pulses and in low-gradient field distributions, whereas myelinated axons are mostly unaffected. The modified cable equation captures the membrane's behavior on different time scales and models more accurately the coupling between electric fields and neurons. It addresses the limitations of the conventional cable equation and allows sound theoretical interpretations. The implementation provides simple methods that are compatible with current simulation approaches to study the effect of transverse polarization on nonlinear membranes. The minimal influence by transverse polarization on axonal activation thresholds for the nonlinear membrane models indicates that

  12. A new multiconstraint method for determining the optimal cable stresses in cable-stayed bridges.

    Science.gov (United States)

    Asgari, B; Osman, S A; Adnan, A

    2014-01-01

    Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM). The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.

  13. Nonlinear Analysis of Cable Vibration of a Multispan Cable-Stayed Bridge under Transverse Excitation

    Directory of Open Access Journals (Sweden)

    Kun Lin

    2014-01-01

    Full Text Available The nonlinear vibrations of cable in a multispan cable-stayed bridge subjected to transverse excitation are investigated. The MECS (multielements cable system model, where multielements per cable stay are used, is built up and used to analyze the model properties of the multispan cable-stayed bridges. Then, a simplified two-degrees-of-freedom (2-DOFs model, where the tower or the deck is reduced to a beam, is proposed to analyze the nonlinear dynamic behaviors of the beam and cable. The results of MECS model analysis show that the main tower in the multispan cable-stayed bridge is prone to the transverse vibration, and the local vibration of cables only has a little impact on the frequency values of the global modes. The results of simplified model analysis show that the energy can be transformed between the modes of the beam and cable when the nature frequencies of them are very close. On the other hand, with the transverse excitation changing, the cable can exhibit richer quasi-periodic or chaotic motions due to the nonlinear terms caused by the coupled mode between the beam and cable.

  14. A New Multiconstraint Method for Determining the Optimal Cable Stresses in Cable-Stayed Bridges

    Directory of Open Access Journals (Sweden)

    B. Asgari

    2014-01-01

    Full Text Available Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM. The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.

  15. Switching Restrikes in HVAC Cable Lines and Hybrid HVAC Cable/OHL Lines

    DEFF Research Database (Denmark)

    da Silva, Filipe Miguel Faria; Bak, Claus Leth; Balle Holst, Per

    2011-01-01

    The disconnection of HV underground cables may, if unsuccessful, originate a restrike in the circuit breaker, leading to high overvoltages, and potentially damaging the cable and near equipment. Due to the cable high capacitance and low resistance the voltage damping is slow, resulting, half...... a cycle after the disconnection, in a voltage of approximately 2 pu at the circuit breaker terminals. In case of restrike in that instant, it is theoretical possible to attain an overvoltage of 3 pu. The overvoltage can be even larger in hybrid cable-Overhead Lines (OHL), due to voltage magnifications...... in the junction point. This paper explains the phenomenon for pure cable lines and hybrid cable-OHL lines, and uses Denmark’s high voltage transmission grid, as planned for the year 2030, as test system. The accuracy of different cable models, and the number of substations from the transient event requiring...

  16. Wind-induced vibration of stay cables

    Science.gov (United States)

    2007-08-01

    Cable-stayed bridges have become the form of choice over the past several decades for bridges in the medium- to long-span range. In some cases, serviceability problems involving large amplitude vibrations of stay cables under certain wind and rain co...

  17. MVAC Submarine cable, impedance measurements and analysis

    DEFF Research Database (Denmark)

    Arentsen, Martin Trolle; Pedersen, Morten Virklund; Expethit, Adrian

    2017-01-01

    Due to environmental concerns an increase in off-shore windfarms has been observed in recent years, leading to an increased demand for three-core-wire-armoured submarine cables. However, the IEC Standard 60287 used to calculate the ampacity of these cables is widely recognized as being not accurate...

  18. 30 CFR 18.45 - Cable reels.

    Science.gov (United States)

    2010-07-01

    ... constitute an integral part of a circuit for transmitting electrical energy. (d) Cable reels for shuttle cars... MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Construction and Design Requirements § 18.45 Cable reels. (a) A self-propelled machine, that receives electrical energy through a portable...

  19. Pay Cable: A Viable Advertising Medium?

    Science.gov (United States)

    Krugman, Dean M.; Barban, Arnold M.

    Cable television, which cannot only clarify local signals to weak signal areas but can also bring in distant signals to areas which have been receiving few signals, has the capacity to present special television programs to customers for extra fees. The number of pay cable subscribers is growing and industry projections are that it will reach 20…

  20. The Status of Cable Communications in Libraries.

    Science.gov (United States)

    Kenney, Brigitte L.

    Librarians are and will be using cable television technologies to enhance and extend their services. While questions remain in regard to the technology itself, the health and viability of the industry, and government policy, librarians are seeing cable communications as an opportunity to gain credibility and visibility, and also as an extension of…

  1. When is hardwood cable logging economical?

    Science.gov (United States)

    Chris B. LeDoux

    1985-01-01

    Using cable logging to harvest eastern hardwood logs on steep terrain can result in low production rates and high costs per unit of wood produced. Logging managers can improve productivity and profitability by knowing how the interaction of site-specific variables and cable logging equipment affect costs and revenues. Data from selected field studies and forest model...

  2. Assessment of sodium conductor distribution cable

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-06-01

    The study assesses the barriers and incentives for using sodium conductor distribution cable. The assessment considers environmental, safety, energy conservation, electrical performance and economic factors. Along with all of these factors considered in the assessment, the sodium distribution cable system is compared to the present day alternative - an aluminum conductor system. (TFD)

  3. Performance Improvement of a Measurement Station for Superconducting Cable Test

    CERN Document Server

    Arpaia, P; Montenero, G; Le Naour, S

    2012-01-01

    A fully digital system, improving measurements flexibility, integrator drift, and current control of superconducting transformers for cable test, is proposed. The system is based on a high-performance integration of Rogowski coil signal and a flexible direct control of the current into the secondary windings. This allows state-of-the-art performance to be overcome by means of out-of-the-shelf components: on a full-scale of 32 kA, current measurement resolution of 1 A, stability below 0.25 Amin-1, and controller ripple less than 50 ppm. The system effectiveness has been demonstrated experimentally on the superconducting transformer of the Facility for the Research of Superconducting Cables at the European Organization for Nuclear Research (CERN).

  4. Fire-safety engineering and performance-based codes

    DEFF Research Database (Denmark)

    Sørensen, Lars Schiøtt

    project administrators, etc. The book deals with the following topics: • Historical presentation on the subject of fire • Legislation and building project administration • European fire standardization • Passive and active fire protection • Performance-based Codes • Fire-safety Engineering • Fundamental...... thermodynamics • Heat exchange during the fire process • Skin burns • Burning rate, energy release rate and design fires • Proposal to Risk-based design fires • Proposal to a Fire scale • Material ignition and flame spread • Fire dynamics in buildings • Combustion products and toxic gases • Smoke inhalation...

  5. Bench-scale Development of an Advanced Solid Sorbent-based CO2 Capture Process for Coal-fired Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Thomas [Research Triangle Institute (RTI), Research Triangle Park, NC (United States); Kataria, Atish [Research Triangle Institute (RTI), Research Triangle Park, NC (United States); Soukri, Mustapha [Research Triangle Institute (RTI), Research Triangle Park, NC (United States); Farmer, Justin [Research Triangle Institute (RTI), Research Triangle Park, NC (United States); Mobley, Paul [Research Triangle Institute (RTI), Research Triangle Park, NC (United States); Tanthana, Jak [Research Triangle Institute (RTI), Research Triangle Park, NC (United States); Wang, Dongxiang [Research Triangle Institute (RTI), Research Triangle Park, NC (United States); Wang, Xiaoxing [Research Triangle Institute (RTI), Research Triangle Park, NC (United States); Song, Chunshan [Research Triangle Institute (RTI), Research Triangle Park, NC (United States)

    2015-12-31

    It is increasingly clear that CO2 capture and sequestration (CCS) must play a critical role in curbing worldwide CO2 emissions to the atmosphere. Development of these technologies to cost-effectively remove CO2 from coal-fired power plants is very important to mitigating the impact these power plants have within the world’s power generation portfolio. Currently, conventional CO2 capture technologies, such as aqueous-monoethanolamine based solvent systems, are prohibitively expensive and if implemented could result in a 75 to 100% increase in the cost of electricity for consumers worldwide. Solid sorbent CO2 capture processes – such as RTI’s Advanced Solid Sorbent CO2, Capture Process – are promising alternatives to conventional, liquid solvents. Supported amine sorbents – of the nature RTI has developed – are particularly attractive due to their high CO2 loadings, low heat capacities, reduced corrosivity/volatility and the potential to reduce the regeneration energy needed to carry out CO2 capture. Previous work in this area has failed to adequately address various technology challenges such as sorbent stability and regenerability, sorbent scale-up, improved physical strength and attrition-resistance, proper heat management and temperature control, proper solids handling and circulation control, as well as the proper coupling of process engineering advancements that are tailored for a promising sorbent technology. The remaining challenges for these sorbent processes have provided the framework for the project team’s research and development and target for advancing the technology beyond lab- and bench-scale testing. Under a cooperative agreement with the US Department of Energy, and part of NETL’s CO2 Capture Program, RTI has led an effort to address and mitigate the challenges associated with solid sorbent CO2 capture. The overall objective

  6. How Fire History, Fire Suppression Practices and Climate Change Affect Wildfire Regimes in Mediterranean Landscapes

    Science.gov (United States)

    Brotons, Lluís; Aquilué, Núria; de Cáceres, Miquel; Fortin, Marie-Josée; Fall, Andrew

    2013-01-01

    Available data show that future changes in global change drivers may lead to an increasing impact of fires on terrestrial ecosystems worldwide. Yet, fire regime changes in highly humanised fire-prone regions are difficult to predict because fire effects may be heavily mediated by human activities We investigated the role of fire suppression strategies in synergy with climate change on the resulting fire regimes in Catalonia (north-eastern Spain). We used a spatially-explicit fire-succession model at the landscape level to test whether the use of different firefighting opportunities related to observed reductions in fire spread rates and effective fire sizes, and hence changes in the fire regime. We calibrated this model with data from a period with weak firefighting and later assess the potential for suppression strategies to modify fire regimes expected under different levels of climate change. When comparing simulations with observed fire statistics from an eleven-year period with firefighting strategies in place, our results showed that, at least in two of the three sub-regions analysed, the observed fire regime could not be reproduced unless taking into account the effects of fire suppression. Fire regime descriptors were highly dependent on climate change scenarios, with a general trend, under baseline scenarios without fire suppression, to large-scale increases in area burnt. Fire suppression strategies had a strong capacity to compensate for climate change effects. However, strong active fire suppression was necessary to accomplish such compensation, while more opportunistic fire suppression strategies derived from recent fire history only had a variable, but generally weak, potential for compensation of enhanced fire impacts under climate change. The concept of fire regime in the Mediterranean is probably better interpreted as a highly dynamic process in which the main determinants of fire are rapidly modified by changes in landscape, climate and

  7. How fire history, fire suppression practices and climate change affect wildfire regimes in Mediterranean landscapes.

    Directory of Open Access Journals (Sweden)

    Lluís Brotons

    Full Text Available Available data show that future changes in global change drivers may lead to an increasing impact of fires on terrestrial ecosystems worldwide. Yet, fire regime changes in highly humanised fire-prone regions are difficult to predict because fire effects may be heavily mediated by human activities We investigated the role of fire suppression strategies in synergy with climate change on the resulting fire regimes in Catalonia (north-eastern Spain. We used a spatially-explicit fire-succession model at the landscape level to test whether the use of different firefighting opportunities related to observed reductions in fire spread rates and effective fire sizes, and hence changes in the fire regime. We calibrated this model with data from a period with weak firefighting and later assess the potential for suppression strategies to modify fire regimes expected under different levels of climate change. When comparing simulations with observed fire statistics from an eleven-year period with firefighting strategies in place, our results showed that, at least in two of the three sub-regions analysed, the observed fire regime could not be reproduced unless taking into account the effects of fire suppression. Fire regime descriptors were highly dependent on climate change scenarios, with a general trend, under baseline scenarios without fire suppression, to large-scale increases in area burnt. Fire suppression strategies had a strong capacity to compensate for climate change effects. However, strong active fire suppression was necessary to accomplish such compensation, while more opportunistic fire suppression strategies derived from recent fire history only had a variable, but generally weak, potential for compensation of enhanced fire impacts under climate change. The concept of fire regime in the Mediterranean is probably better interpreted as a highly dynamic process in which the main determinants of fire are rapidly modified by changes in landscape

  8. Frequency Dependent Losses in Transmission Cable Conductors

    DEFF Research Database (Denmark)

    Olsen, Rasmus Schmidt; Holbøll, Joachim; Guðmundsdóttir, Unnur Stella

    2011-01-01

    and economical gain, such severe network changes necessitate correct estimation and optimisation of load conditions in the cable grid. Both IEC and IEEE have published standards for rating transmission cables' current carrying capacity. These standards are based on assumptions of a number of parameters......, such as thermal conditions in and around the cable, as well as the heat generated in conductors, screens, armours etc., taking into account proximity and skin effects. The work performed and presented in this paper is concerned with an improved determination of the losses generated in the conductor, by means...... of better calculation of the AC resistance of transmission cable conductors, in particular regarding higher frequencies. In this way, also losses under harmonics can be covered. Furthermore, the model is suitable for modelling of transient attenuation in high voltage cables. The AC resistance is calculated...

  9. Counter-balanced, multiple cable construction crane

    Science.gov (United States)

    Mikulas, Martin M., Jr. (Inventor); Yang, Li-Farn (Inventor)

    1993-01-01

    The invention is a counter-balanced, multiple cable construction crane. The apparatus for hoisting payloads comprises a crane having a lifting means, the lifting means comprising an end effector means and three suspension means or cables. One end of each cable attaches to a different winding means located on the lifting means, and the other end of each cable attaches to a different point on the end effector, such that the three cables have a theoretical point of convergence with this point corresponding to the center of mass of the payload. Three controls command rotation of the winding means to a predetermined position. Accordingly, the crane provides precise and autonomous positioning of the payload without human guidance. The crane further comprises a counter-balancing means. Two controls position the counter-balancing means to offset the overturning moment which arises during the lifting of heavy payloads.

  10. Government Districts, Other, Voting districts, fire districts, inspector districts, engineering districts, school zones, recreation leagues, Published in 2014, Not Applicable scale, City of Huntsville Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Government Districts, Other dataset current as of 2014. Voting districts, fire districts, inspector districts, engineering districts, school zones, recreation leagues.

  11. Wildland fire limits subsequent fire occurrence

    Science.gov (United States)

    Sean A. Parks; Carol Miller; Lisa M. Holsinger; Scott Baggett; Benjamin J. Bird

    2016-01-01

    Several aspects of wildland fire are moderated by site- and landscape-level vegetation changes caused by previous fire, thereby creating a dynamic where one fire exerts a regulatory control on subsequent fire. For example, wildland fire has been shown to regulate the size and severity of subsequent fire. However, wildland fire has the potential to influence...

  12. Power cables with extruded insulation and their accessories for rated voltages from 1 kV (Um = 1,2 kV) up to 30 kV (Um = 36 kV) - Part 1: Cables for rated voltages of 1 kV (Um = 1,2 kV) and 3 kV (Um = 3,6 kV)

    CERN Document Server

    International Electrotechnical Commission. Geneva

    2004-01-01

    Specifies the construction, dimensions and test requirements of power cables with extruded solid insulation for rated voltages of 1 kV (Um = 1,2 kV) and 3 kV (Um = 3,6 kV) for fixed installations such as distribution networks or industrial installations. This standard includes cables which exhibit properties of reduced flame spread, low levels of smoke emission and halogen-free gas emission when exposed to fire. Cables for special installation and service conditions are not included, for example cables for overhead networks, the mining industry, nuclear power plants (in and around the containment area), submarine use or shipboard application. The main changes with respect to the first edition relate to insulation and oversheath thickness requirements, and inclusion of constructions and requirements for halogen free cables with reduced flame propagation and low levels of smoke emission.

  13. Nuclear power plant cable materials :

    Energy Technology Data Exchange (ETDEWEB)

    Celina, Mathias C.; Gillen, Kenneth T; Lindgren, Eric Richard

    2013-05-01

    A selective literature review was conducted to assess whether currently available accelerated aging and original qualification data could be used to establish operational margins for the continued use of cable insulation and jacketing materials in nuclear power plant environments. The materials are subject to chemical and physical degradation under extended radiationthermal- oxidative conditions. Of particular interest were the circumstances under which existing aging data could be used to predict whether aged materials should pass loss of coolant accident (LOCA) performance requirements. Original LOCA qualification testing usually involved accelerated aging simulations of the 40-year expected ambient aging conditions followed by a LOCA simulation. The accelerated aging simulations were conducted under rapid accelerated aging conditions that did not account for many of the known limitations in accelerated polymer aging and therefore did not correctly simulate actual aging conditions. These highly accelerated aging conditions resulted in insulation materials with mostly inert aging processes as well as jacket materials where oxidative damage dropped quickly away from the air-exposed outside jacket surface. Therefore, for most LOCA performance predictions, testing appears to have relied upon heterogeneous aging behavior with oxidation often limited to the exterior of the cable cross-section a situation which is not comparable with the nearly homogenous oxidative aging that will occur over decades under low dose rate and low temperature plant conditions. The historical aging conditions are therefore insufficient to determine with reasonable confidence the remaining operational margins for these materials. This does not necessarily imply that the existing 40-year-old materials would fail if LOCA conditions occurred, but rather that unambiguous statements about the current aging state and anticipated LOCA performance cannot be provided based on

  14. Emergency escape system protects personnel from explosion and fire

    Science.gov (United States)

    Offik, W. G.

    1966-01-01

    Elevator-type emergency escape system evacuates personnel from tall structures, especially when the possibility of explosion or fire exists. The system consists of a spike shaped rescue cabin which descends along a vertical guide cable, penetrates the dome shaped roof of an underground blast shelter and stops in a deceleration bed of granular material.

  15. Wind-induced cable vibrations and countermeasures of cables of PC cable-stayed bridge. PC syachokyo keburu no kaze ni yoru shindo to sono taisaku

    Energy Technology Data Exchange (ETDEWEB)

    Yoneda, M. (Kawada Industries Inc., Tokyo (Japan))

    1994-05-01

    In recent years, long span of cable-stayed bridges is remarkable. The wind-induced cable vibration called as line vibration and wake galloping was given as an important problem not only in the steel cable-stayed bridges but also in the PC cable-stayed bridges. The technical engineers in design of the cable-stayed bridges have many times to confront the problems on the vibration control of cables, it is considered that sufficient understand of the wind-induced vibration and countermeasures for cables of the PC cable-stayed bridges is necessary. Many reports on the countermeasure examples and trend of vibration control centred on cables of the cable-stayed bridges have been published. In this paper, the wind-induced vibration of cables in the cable-stayed bridges was reviewed, the examples of countermeasures of vibration control on cables in the PC cable-stayed bridges was mainly introduced. The remaining tasks and future prospects on vibration control of the PC cable-stayed bridges were described. 14 refs., 13 figs., 4 tabs.

  16. Fire Hydrants, Fire hydrants outside the City of Wichita. Primary attributes include hydrant number and ID. Layer is under development by Sedgwick County Fire Department. Primary attributes include GPS status, feature-mapped-to, hydrants ID, address, situs city, mai, Published in 2008, 1:1200 (1in=100ft) scale, Sedgwick County Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Fire Hydrants dataset current as of 2008. Fire hydrants outside the City of Wichita. Primary attributes include hydrant number and ID. Layer is under development by...

  17. Land cover mapping, fire regeneration, and scaling studies in the Canadian boreal forest with 1 km AVHRR and Landsat TM data

    Science.gov (United States)

    Steyaert, L. T.; Hall, F. G.; Loveland, T. R.

    1997-12-01

    A multitemporal 1 km advanced very high resolution radiometer (AVHRR) land cover analysis approach was used as the basis for regional land cover mapping, fire disturbance-regeneration, and multiresolution land cover scaling studies in the boreal forest ecosystem of central Canada. The land cover classification was developed by using regional field observations from ground and low-level aircraft transits to analyze spectral-temporal clusters that were derived from an unsupervised cluster analysis of monthly normalized difference vegetation index (NDVI) image composites (April-September 1992). Quantitative areal proportions of the major boreal forest components were determined for a 821 km × 619 km region, ranging from the southern grasslands-boreal forest ecotone to the northern boreal transitional forest. The boreal wetlands (mostly lowland black spruce, tamarack, mosses, fens, and bogs) occupied approximately 33% of the region, while lakes accounted for another 13%. Upland mixed coniferous-deciduous forests represented 23% of the ecosystem. A SW-NE productivity gradient across the region is manifested by three levels of tree stand density for both the boreal wetland conifer and the mixed forest classes, which are generally aligned with isopleths of regional growing degree days. Approximately 30% of the region was directly affected by fire disturbance within the preceding 30-35 years, especially in the Canadian Shield Zone where large fire-regeneration patterns contribute to the heterogeneous boreal landscape. Intercomparisons with land cover classifications derived from 30-m Landsat Thematic Mapper (TM) data provided important insights into the relative accuracy of the 1 km AVHRR land cover classification. Primarily due to the multitemporal NDVI image compositing process, the 1 km AVHRR land cover classes have an effective spatial resolution in the 3-4 km range; therefore fens, bogs, small water bodies, and small patches of dry jack pine cannot be resolved within

  18. Land cover mapping, fire regeneration, and scaling studies in the Canadian boreal forest with 1 km AVHRR and Landsat TM data

    Science.gov (United States)

    Steyaert, L.T.; Hall, F.G.; Loveland, T.R.

    1997-01-01

    A multitemporal 1 km advanced very high resolution radiometer (AVHRR) land cover analysis approach was used as the basis for regional land cover mapping, fire disturbance-regeneration, and multiresolution land cover scaling studies in the boreal forest ecosystem of central Canada. The land cover classification was developed by using regional field observations from ground and low-level aircraft transits to analyze spectral-temporal clusters that were derived from an unsupervised cluster analysis of monthly normalized difference vegetation index (NDVI) image composites (April-September 1992). Quantitative areal proportions of the major boreal forest components were determined for a 821 km ?? 619 km region, ranging from the southern grasslands-boreal forest ecotone to the northern boreal transitional forest. The boreal wetlands (mostly lowland black spruce, tamarack, mosses, fens, and bogs) occupied approximately 33% of the region, while lakes accounted for another 13%. Upland mixed coniferous-deciduous forests represented 23% of the ecosystem. A SW-NE productivity gradient across the region is manifested by three levels of tree stand density for both the boreal wetland conifer and the mixed forest classes, which are generally aligned with isopleths of regional growing degree days. Approximately 30% of the region was directly affected by fire disturbance within the preceding 30-35 years, especially in the Canadian Shield Zone where large fire-regeneration patterns contribute to the heterogeneous boreal landscape. Intercomparisons with land cover classifications derived from 30-m Landsat Thematic Mapper (TM) data provided important insights into the relative accuracy of the 1 km AVHRR land cover classification. Primarily due to the multitemporal NDVI image compositing process, the 1 km AVHRR land cover classes have an effective spatial resolution in the 3-4 km range; therefore fens, bogs, small water bodies, and small patches of dry jack pine cannot be resolved within

  19. A Cable-tunnel Inspecting Robot for Dangerous Environment

    Directory of Open Access Journals (Sweden)

    Fu Zhuang

    2008-11-01

    Full Text Available This paper presents a kind of mobile robot used for inspecting the cable tunnel online in the dangerous environment. Usually, the calble tunnel is full of poisonous gases after fire, such as CO,CH4, CO2 and so on. Then, the mobile robot is able to tell us whether the tunnel environment is safe or not. In this paper the architecture of the robot is designed at first to meet the motion requirement in the tunnel. These characteristics distinguish the mobile robot from others like compact structure,small size,little weight and easily being carried. Next, the moving mechanism and its kinematics are described. And thus, the operating procedure and experiments are introuduced to validate its reliablity.

  20. Designing Predictive Diagnose Method for Insulation Resistance Degradation of the Electrical Power Cables from Neutral Insulated Power Networks

    Science.gov (United States)

    Dobra, R.; Pasculescu, D.; Risteiu, M.; Buica, G.; Jevremović, V.

    2017-06-01

    This paper describe some possibilities to minimize voltages switching-off risks from the mining power networks, in case of insulated resistance faults by using a predictive diagnose method. The cables from the neutral insulated power networks (underground mining) are designed to provide a flexible electrical connection between portable or mobile equipment and a point of supply, including main feeder cable for continuous miners, pump cable, and power supply cable. An electronic protection for insulated resistance of mining power cables can be made using this predictive strategy. The main role of electronic relays for insulation resistance degradation of the electrical power cables, from neutral insulated power networks, is to provide a permanent measurement of the insulated resistance between phases and ground, in order to switch-off voltage when the resistance value is below a standard value. The automat system of protection is able to signalize the failure and the human operator will be early informed about the switch-off power and will have time to take proper measures to fix the failure. This logic for fast and automat switch-off voltage without aprioristic announcement is suitable for the electrical installations, realizing so a protection against fires and explosion. It is presented an algorithm and an anticipative relay for insulated resistance control from three-phase low voltage installations with insulated neutral connection.

  1. Coal fires in Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Whitehouse, Alfred E.; Mulyana, Asep A.S. [Office of Surface Mining/Ministry of Energy and Mineral Resources Coal Fire Project, Ministry of Energy and Mineral Resources, Agency for Training and Education, Jl. Gatot Subroto, Kav. 49, Jakarta 12950 (Indonesia)

    2004-07-12

    Indonesia's fire and haze problem is increasingly being ascribed to large-scale forest conversion and land clearing activities making way for pulpwood, rubber and oil palm plantations. Fire is the cheapest tool available to small holders and plantation owners to reduce vegetation cover and prepare and fertilize extremely poor soils. Fires that escaped from agricultural burns have ravaged East Kalimantan forests on the island of Borneo during extreme drought periods in 1982-1983, 1987, 1991, 1994 and 1997-1998. Estimates based on satellite data and ground observations are that more than five million hectares were burned in East Kalimantan during the 1997/1998 dry season. Not only were the economic losses and ecological damage from these surface fires enormous, they ignited coal seams exposed at the ground surface along their outcrops.Coal fires now threaten Indonesia's shrinking ecological resources in Kutai National Park and Sungai Wain Nature Reserve. Sungai Wain has one of the last areas of unburned primary rainforest in the Balikpapan-Samarinda area with an extremely rich biodiversity. Although fires in 1997/1998 damaged nearly 50% of this Reserve and ignited 76 coal fires, it remains the most valuable water catchment area in the region and it has been used as a reintroduction site for the endangered orangutan. The Office of Surface Mining provided Indonesia with the capability to take quick action on coal fires that presented threats to public health and safety, infrastructure or the environment. The US Department of State's Southeast Asia Environmental Protection Initiative through the US Agency for International Development funded the project. Technical assistance and training transferred skills in coal fire management through the Ministry of Energy and Mineral Resource's Training Agency to the regional offices; giving the regions the long-term capability to manage coal fires. Funding was also included to extinguish coal fires as

  2. Application of Pulse Spark Discharges for Scale Prevention and Continuous Filtration Methods in Coal-Fired Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young; Fridman, Alexander

    2012-06-30

    The overall objective of the present work was to develop a new scale-prevention technology by continuously precipitating and removing dissolved mineral ions (such as calcium and magnesium) in cooling water while the COC could be doubled from the present standard value of 3.5. The hypothesis of the present study was that if we could successfully precipitate and remove the excess calcium ions in cooling water, we could prevent condenser-tube fouling and at the same time double the COC. The approach in the study was to utilize pulse spark discharges directly in water to precipitate dissolved mineral ions in recirculating cooling water into relatively large suspended particles, which could be removed by a self-cleaning filter. The present study began with a basic scientific research to better understand the mechanism of pulse spark discharges in water and conducted a series of validation experiments using hard water in a laboratory cooling tower. Task 1 of the present work was to demonstrate if the spark discharge could precipitate the mineral ions in water. Task 2 was to demonstrate if the selfcleaning filter could continuously remove these precipitated calcium particles such that the blowdown could be eliminated or significantly reduced. Task 3 was to demonstrate if the scale could be prevented or minimized at condenser tubes with a COC of 8 or (almost) zero blowdown. In Task 1, we successfully completed the validation study that confirmed the precipitation of dissolved calcium ions in cooling water with the supporting data of calcium hardness over time as measured by a calcium ion probe. In Task 2, we confirmed through experimental tests that the self-cleaning filter could continuously remove precipitated calcium particles in a simulated laboratory cooling tower such that the blowdown could be eliminated or significantly reduced. In addition, chemical water analysis data were obtained which were used to confirm the COC calculation. In Task 3, we conducted a series

  3. Controls on carbon consumption during Alaskan wildland fires

    Science.gov (United States)

    Eric S. Kasischke; Elizabeth E. Hoy

    2012-01-01

    A method was developed to estimate carbon consumed during wildland fires in interior Alaska based on medium-spatial scale data (60 m cell size) generated on a daily basis. Carbon consumption estimates were developed for 41 fire events in the large fire year of 2004 and 34 fire events from the small fire years of 2006-2008. Total carbon consumed during the large fire...

  4. Laboratory-scale evaluation of various sampling and analytical methods for determining mercury emissions from coal-fired power plants

    Energy Technology Data Exchange (ETDEWEB)

    Agbede, R.O.; Bochan, A.J.; Clements, J.L. [Advanced Technology Systems, Inc., Monroeville, PA (United States)] [and others

    1995-11-01

    Comparative bench-scale mercury sampling method tests were performed at the Advanced Technology Systems, Inc. (ATS) laboratories for EPA Method 101A, EPA Method 29 and the Ontario Hydro Method. Both blank and impinger spiking experiments were performed. The experimental results show that the ambient level of mercury in the ATS laboratory is at or below the detection limit (10 ng Hg) as measured by a cold vapor atomic absorption spectrophotometer (CVAAS) which was used to analyze the mercury samples. From the mercury spike studies, the following observations and findings were made. (a) The recovery of mercury spikes using EPA Method 101A was 104%. (b) The Ontario Hydro Method retains about 90% of mercury spikes in the first absorbing solution but has a total spike retention of 106%. As a result, the test data shows possible migration of spiked mercury from the first impinger solution (KCI) to the permanganate impingers. (c) For the EPA Method 29 solutions, when only the peroxide impingers were spiked, mercury recoveries were 65.6% for the peroxide impingers, 0.1% for the knockout impinger and 32.8% for the permanganate impingers with an average total mercury recovery of 98.4%. At press time, data was still being obtained for both the peroxide and permanganate impinger solution spikes. This and other data will be available at the presentation.

  5. Dynamics of an Anthropogenic Fire Regime

    Science.gov (United States)

    R. P. Guyette; R. M. Muzika; D. C. Dey

    2002-01-01

    Human interaction with fire and vegetation occurs at many levels of human population density and cultural development, from subsistence cultures to highly technological societies. The dynamics of these interactions with respect to wildland fire are often difficult to understand and identify at short temporal scales. Dendrochronological fire histories from the Missouri...

  6. Numerical simulation of dynamic characteristics of a cable-stayed aqueduct bridge

    Science.gov (United States)

    Li, Yuchun; di, Qingshuang

    2011-12-01

    In this paper, a full-scale 3-D finite element model of the Jundushan cable-stayed aqueduct bridge is established with ANSYS Code. The shell, fluid, tension-only spar and beam elements are used for modeling the aqueduct deck, filled water, cables and support towers, respectively. A multi-element cable formulation is introduced to simulate the cable vibration. The dry (without water) and wet (with water) modes of the aqueduct bridge are both extracted and investigated in detail. The dry modes of the aqueduct bridge are basically similar to those of highway cable-stayed bridges. A dry mode may correspond to two types of wet modes, which are called the in-phase (with lower frequency) and out-of-phase (with higher frequency) modes. When the water-structure system vibrates in the in-phase/out-of-phase modes, the aqueduct deck moves and water sloshes in the same/opposite phase-angle, and the sloshing water may take different surface-wave modes. The wet modes of the system reflect the properties of interaction among the deck, towers, cables and water. The in-phase wet frequency generally decreases as the water depth increases, and the out-of-phase wet frequency may increase or decrease as the water depth increases.

  7. Self-healing cable for extreme environments

    Science.gov (United States)

    Huston, Dryver R. (Inventor); Tolmie, Bernard R. (Inventor)

    2009-01-01

    Self-healing cable apparatus and methods disclosed. The self-healing cable has a central core surrounded by an adaptive cover that can extend over the entire length of the self-healing cable or just one or more portions of the self-healing cable. The adaptive cover includes an axially and/or radially compressible-expandable (C/E) foam layer that maintains its properties over a wide range of environmental conditions. A tape layer surrounds the C/E layer and is applied so that it surrounds and axially and/or radially compresses the C/E layer. When the self-healing cable is subjected to a damaging force that causes a breach in the outer jacket and the tape layer, the corresponding localized axially and/or radially compressed portion of the C/E foam layer expands into the breach to form a corresponding localized self-healed region. The self-healing cable is manufacturable with present-day commercial self-healing cable manufacturing tools.

  8. Effects of surface roughness and cross-sectional distortions on the wind-induced response of bridge cables in dry conditions

    DEFF Research Database (Denmark)

    Matteoni, Giulia; Georgakis, Christos T.

    drag and lift coefficients. The present study focuses on the dynamic response of a full-scale yawed bridge cable section model, for varying Reynolds numbers and wind angles-of-attack. Tests results show that the in-plane aerodynamic damping of the bridge cable section, and the overall dynamic response......Theoretical and experimental investigations to date assumed that bridge stay cables can be modelled as ideal circular cylinders and that their aerodynamic coefficients are invariant with wind angle-of-attack. These changes are neglected when the potential for bridge cable instability is evaluated...

  9. Introduction of Integrity Evaluation Criteria Developing during and after fire for Nuclear Power Plant Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin Woo [KEPCo, Gimcheon (Korea, Republic of)

    2016-05-15

    The first project for nuclear power plant built in Korea to taking account the engineering based approach was started on October 2015 including the whole process such as fire hazard analysis, standard fire modeling, cable tray fire with multi spurious operation, structural fire integrity evaluation, and large area fire induced air craft crash. This paper covers the brief developing scheme and roadmap focusing on structural fire evaluation criteria. The meaningful first step for developing the structural fire integrity in nuclear power plant building is started with the series of fire related sub sections mentioned in earlier section. The recognition and sufficient effort of fire research leads to set up the safe and reliable design of nuclear power plant.

  10. Non-linear stochastic response of a shallow cable

    DEFF Research Database (Denmark)

    Larsen, Jesper Winther; Nielsen, Søren R.K.

    2004-01-01

    The paper considers the stochastic response of geometrical non-linear shallow cables. Large rain-wind induced cable oscillations with non-linear interactions have been observed in many large cable stayed bridges during the last decades. The response of the cable is investigated for a reduced two...

  11. Choice Of Computer Networking Cables And Their Effect On Data ...

    African Journals Online (AJOL)

    Computer networking is the order of the day in this Information and Communication Technology (ICT) age. Although a network can be through a wireless device most local connections are done using cables. There are three main computer-networking cables namely coaxial cable, unshielded twisted pair cable and the optic ...

  12. 46 CFR 111.60-4 - Minimum cable conductor size.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Minimum cable conductor size. 111.60-4 Section 111.60-4...-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-4 Minimum cable conductor size. Each cable conductor must be #18 AWG (0.82 mm2) or larger except— (a) Each power and lighting cable conductor must be...

  13. Multiconductor Short/Open Cable Tester

    Science.gov (United States)

    Eichenberg, Dennis

    1994-01-01

    Frequent or regular testing of multiconductor cables terminated in multipin conductors tedious, if not impossible, task. This inexpensive circuit simplifies open/short testing and is amenable to automation. In operation, pair of connectors selected to match pair of connectors installed on each of cables to be tested. As many connectors accommodated as required, and each can have as many conductors as required. Testing technique implemented with this circuit automated easily with electronic controls and computer interface. Printout provides status of each conductor in cable, indicating which, if any, of conductors has open or short circuit.

  14. Fire danmarkskort

    DEFF Research Database (Denmark)

    Pedersen, Birger Faurholt

    2017-01-01

    Fire danmarkskort udarbejdet på baggrund af dataudtræk fra indsendte gødningsregnskaber for planperioden 2015/2016......Fire danmarkskort udarbejdet på baggrund af dataudtræk fra indsendte gødningsregnskaber for planperioden 2015/2016...

  15. On fire

    DEFF Research Database (Denmark)

    Hansen, Helle Rabøl

    The title of this paper: “On fire”, refers to two (maybe three) aspects: firstly as a metaphor of having engagement in a community of practice according to Lave & Wenger (1991), and secondly it refers to the concrete element “fire” in the work of the fire fighters – and thirdly fire as a signifier...

  16. Fire Power

    Science.gov (United States)

    Denker, Deb; West, Lee

    2009-01-01

    For education administrators, campus fires are not only a distressing loss, but also a stark reminder that a campus faces risks that require special vigilance. In many ways, campuses resemble small communities, with areas for living, working and relaxing. A residence hall fire may raise the specter of careless youth, often with the complication of…

  17. Forest-fire models

    Science.gov (United States)

    Haiganoush Preisler; Alan Ager

    2013-01-01

    For applied mathematicians forest fire models refer mainly to a non-linear dynamic system often used to simulate spread of fire. For forest managers forest fire models may pertain to any of the three phases of fire management: prefire planning (fire risk models), fire suppression (fire behavior models), and postfire evaluation (fire effects and economic models). In...

  18. 46 CFR 28.315 - Fire pumps, fire mains, fire hydrants, and fire hoses.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Fire pumps, fire mains, fire hydrants, and fire hoses... After September 15, 1991, and That Operate With More Than 16 Individuals on Board § 28.315 Fire pumps, fire mains, fire hydrants, and fire hoses. (a) Each vessel 36 feet (11.8 meters) or more in length must...

  19. Wire in the Cable-Driven System of Surgical Robot

    Science.gov (United States)

    Wang, X. F.; Lv, N.; Mu, H. Z.; Xue, L. J.

    2017-07-01

    During the evolution of the surgical robot, cable plays an important role. It translates motion and force precisely from surgeon’s hand to the tool’s tips. In the paper, the vertical wires, the composition of cable, are mathematically modeled from a geometric point of view. The cable structure and tension are analyzed according to the characteristics of wire screw twist. The structural equations of the wires in different positions are derived for both non-bent cable and bent cable, respectively. The bending moment formula of bent cable is also obtained. This will help researchers find suitable cable and design more matched pulley.

  20. What Is Data Cabling and Why It's Necessary for Businesses

    OpenAIRE

    IT Support

    2017-01-01

    What is Data Cabling? A structured cabling system is a type of network construction that is open and is used by different systems like data, access management, telephony, building automation, along with many other similar capabilities. It is an extremely flexible and economical set up. Usually, a cabling system such as this can be broken into six components: work space, horizontal cabling, backbone cabling, gear space, telecommunication closet (room) and entrance ways. Common Network ...

  1. MIMO Device Performance Testing with the Wireless Cable Method

    DEFF Research Database (Denmark)

    Fan, Wei; Kyösti, Pekka; Hentilä, Lassi

    2018-01-01

    Conducted cable testing has been dominantly utilized in the industry to evaluate multiple-input multiple-output (MIMO) capable mobile terminals. Desired testing signals can be guided directly to the antenna ports on the mobile terminal by radio frequency (RF) coaxial cables in the conducted cable...... of the wireless cable method is done both in simulation and active throughput measurements. Future directions and applicability of the wireless cable method are also discussed....

  2. Parametrically excited oscillation of stay cable and its control in cable-stayed bridges.

    Science.gov (United States)

    Sun, Bing-nan; Wang, Zhi-gang; Ko, J M; Ni, Y Q

    2003-01-01

    This paper presents a nonlinear dynamic model for simulation and analysis of a kind of parametrically excited vibration of stay cable caused by support motion in cable-stayed bridges. The sag, inclination angle of the stay cable are considered in the model, based on which, the oscillation mechanism and dynamic response characteristics of this kind of vibration are analyzed through numerical calculation. It is noted that parametrically excited oscillation of a stay cable with certain sag, inclination angle and initial static tension force may occur in cable-stayed bridges due to deck vibration under the condition that the natural frequency of a cable approaches to about half of the first model frequency of the bridge deck system. A new vibration control system installed on the cable anchorage is proposed as a possible damping system to suppress the cable parametric oscillation. The numerical calculation results showed that with the use of this damping system, the cable oscillation due to the vibration of the deck and/or towers will be considerably reduced.

  3. On the Minimum Cable Tensions for the Cable-Based Parallel Robots

    Directory of Open Access Journals (Sweden)

    Peng Liu

    2014-01-01

    Full Text Available This paper investigates the minimum cable tension distributions in the workspace for cable-based parallel robots to find out more information on the stability. First, the kinematic model of a cable-based parallel robot is derived based on the wrench matrix. Then, a noniterative polynomial-based optimization algorithm with the proper optimal objective function is presented based on the convex optimization theory, in which the minimum cable tension at any pose is determined. Additionally, three performance indices are proposed to show the distributions of the minimum cable tensions in a specified region of the workspace. An important thing is that the three performance indices can be used to evaluate the stability of the cable-based parallel robots. Furthermore, a new workspace, the Specified Minimum Cable Tension Workspace (SMCTW, is introduced, within which all the minimum tensions exceed a specified value, therefore meeting the specified stability requirement. Finally, a camera robot parallel driven by four cables for aerial panoramic photographing is selected to illustrate the distributions of the minimum cable tensions in the workspace and the relationship between the three performance indices and the stability.

  4. Ecology: Electrical Cable Bacteria Save Marine Life

    DEFF Research Database (Denmark)

    Nielsen, Lars Peter

    2016-01-01

    Animals at the bottom of the sea survive oxygen depletion surprisingly often, and a new study identifies cable bacteria in the sediment as the saviors. The bacterial electrical activity creates an iron 'carpet', trapping toxic hydrogen sulfide....

  5. Thermally induced EMF in unirradiated MI cables

    Science.gov (United States)

    Vila, R.; Hodgson, E. R.

    2007-08-01

    Radiation and temperature induced currents and voltages in mineral insulated (MI) cables, (generally termed RIEMF and TIEMF, respectively) have recently been the object of discussion and study. The problem is due to a possible electromagnetic force (EMF) generated along the centre conductor of ITER magnetic diagnostic coils in a radiation field, and the difficulty of separating radiation and temperature effects from the required signal. Previous work has shown the importance of temperature gradient effects. To address this problem further, studies of TIEMF have been carried out on an MI cable across the ends of the centre conductor at temperatures up to 550 °C, making point-by-point measurements, as well as annealing tests. It has been confirmed that voltage maxima appear in well-localized regions of the cable, indicating that some inhomogeneity is present. No geometric variations were observed by X-ray imaging of the cable.

  6. Bias in Cable News: Persuasion and Polarization

    OpenAIRE

    Martin, Gregory J; Ali Yurukoglu

    2014-01-01

    We measure the persuasive effects of slanted news and tastes for like-minded news, exploiting cable channel positions as exogenous shifters of cable news viewership. Channel positions do not correlate with demographics that predict viewership and voting, nor with local satellite viewership. We estimate that Fox News increases Republican vote shares by 0.3 points among viewers induced into watching 2.5 additional minutes per week by variation in position. We then estimate a model of voters who...

  7. Cable system transients theory, modeling and simulation

    CERN Document Server

    Ametani, Akihiro; Nagaoka, Naoto

    2015-01-01

    A systematic and comprehensive introduction to electromagnetic transient in cable systems, written by the internationally renowned pioneer in this field Presents a systematic and comprehensive introduction to electromagnetic transient in cable systems Written by the internationally renowned pioneer in the field Thorough coverage of the state of the art on the topic, presented in a well-organized, logical style, from fundamentals and practical applications A companion website is available

  8. A Cable-Shaped Lithium Sulfur Battery.

    Science.gov (United States)

    Fang, Xin; Weng, Wei; Ren, Jing; Peng, Huisheng

    2016-01-20

    A carbon nanostructured hybrid fiber is developed by integrating mesoporous carbon and graphene oxide into aligned carbon nanotubes. This hybrid fiber is used as a 1D cathode to fabricate a new cable-shaped lithium-sulfur battery. The fiber cathode exhibits a decent specific capacity and lifespan, which makes the cable-shaped lithium-sulfur battery rank far ahead of other fiber-shaped batteries. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Medical support for the 2009 World Police and Fire Games: a descriptive analysis of a large-scale participation event and its impact.

    Science.gov (United States)

    Gutman, Samuel J; Lund, Adam; Turris, Sheila A

    2011-02-01

    In the summer of 2009, British Columbia hosted the World Police and Fire Games (WPFG). The event brought together 10,599 athletes from 55 countries. In this descriptive, Canadian study, the composition of the medical team is analyzed, the unique challenges faced are discussed, and an analysis of the illness and injury rates is presented. This event occurred during a labor dispute affecting the sole provider of emergency ambulance service in the jurisdiction, which necessitated additional planning and resource allocation. As such, the context of this event as it relates to the literature on mass gathering medicine is discussed with a focus on how large-scale public events can impact emergency services for the community. This is a case report study. There were 1,462 patient encounters. The majority involved musculo-skeletal injuries (53.8%). The patient presentation rate (PPR) was 109.40/1,000. The medical transfer rate (MTR) was 2.32/1,000. The ambulance transfer rate (ATR) for the 2009 WPFG was 0.52/1,000. In total, 31 patients were transported to the hospital, the majority for diagnostic evaluation. Only seven calls were placed to 9-1-1 for emergency ambulance service. The 2009 WPFG was a mass-gathering sporting event that presented specific challenges in relation to medical support. Despite relatively high patient presentation rates, the widely spread geography of the event, and a reduced ability to depend on 9-1-1 emergency medical services, there was minimal impact on local emergency services. Adequate planning and preparation is crucial for events that have the potential to degrade existing public resources and access to emergency health services for participants and the public at large.

  10. Development of new fuels for small-scale installations using cyclone firing; Erschliessung neuer Brennstoffe fuer kleine Leistungsbereiche durch die Wirbelfeuerung

    Energy Technology Data Exchange (ETDEWEB)

    Hamatschek, Eva; Lippmann, Steffen [ATZ Entwicklungszentrum, Sulzbach-Rosenberg (Germany)

    2009-07-01

    Cyclone firing has proved robust and reliable in the investigations carried out to date. Covering a wide range of fuels, these investigations have shown cyclone firing to have the flexibility it was designed for in terms of fuel type and composition, particle size, fuel moisture and ash content. Features deserving special mention are its good burnout and the option of staged combustion to limit NO{sub x} emissions in the case of nitrogen-rich fuels.

  11. Two-way cable television system characterization

    Science.gov (United States)

    Schauer, Paul T.

    1995-11-01

    This presentation is a report of the testing activities of the CableLabs Network Integrity Working Group. The working group consisted of several CableLabs member companies which conducted rf analog and digital bit-error testing at five CATV networks in the U.S. and Canada. The purpose of the working group was to measure the reliability and availability of the contemporary CATV network as specified by traditional switched access telephony performance parameters. Transmission data was collected for both forward and reverse (sub- split) paths of the rf broadband network, in both traditional and hybrid fiber/coax architectures, and for baseline and controlled variation events. The basic premise of this testing was to ascertain which cable television network elements adversely affected transmission of a 'generic' digital communications system and how they can be managed or controlled. The digital transmission utilized in the test was a QPSK modulated, T-1 rate (1.544 Mbit/second), modem without error correction. The intent was not to derive the necessary modulation technique and error correction scheme to properly operate in every cable television system, but rather to determine the principal sources of impairments existing in these networks and deduce corrective measures. The full report of the Network Integrity Working Group is published by CableLabs, Inc., and is titled, 'Two-Way Cable Television System Characterization -- Final Report', April 1995.

  12. Regulatory aspects of fire toxicology.

    Science.gov (United States)

    Nelson, G L

    1987-12-01

    Fire creates a complex toxic environment involving flame, heat, oxygen depletion, smoke, and toxic gases. The nature of that environment is dependent upon not only the materials present but on the fire event, that is, the fire scenario. Materials have different toxic gas profiles under different conditions; therefore, toxic fire gas generation is not intrinsic to any one material. Large fires in buildings constitute a severe toxic threat regardless of the materials being burned. In the past, building codes in the United States included the phrase, "no more toxic than wood," in reference to fire gases from building materials. Such phrases have recently been deleted, because of the lack of either an accepted definition or test methodology to assess toxicity. While several states have attempted regulatory activity, the most recent approach (taken by the state of New York) has been the establishment of a data bank on toxic potency of building and furnishing materials. The utility of such a data bank without available hazard analysis methodology is open to discussion, since toxic potency data are not directly applicable to toxic hazard assessment. A number of small-scale animal exposure tests have been developed to assess the potency of the toxic combustion products from combustible materials. Criticism of these tests relates to the relevance of the combustion module (a smoke generation apparatus) and the appropriateness of the animal model, particularly for irritant gases. Recent data from more than 2000 fire fatality cases and carbon monoxide exposure cases are discussed in this paper to help put small-scale laboratory test results into perspective. Toxicity is only one of the several fire properties related to materials. All fire parameters are interrelated, that is, they are not independent variables. Thus, predicting the toxicity of burning materials is a problem without a comprehensive solution. Measures have been taken, however, to reduce the number of fires and

  13. Environmental assessment of submarine power cables

    Energy Technology Data Exchange (ETDEWEB)

    Isus, Daniel; Martinez, Juan D. [Grupo General Cable Sistemas, S.A., 08560-Manlleu, Barcelona (Spain); Arteche, Amaya; Del Rio, Carmen; Madina, Virginia [Tecnalia Research and Innovation, 20009 San Sebastian (Spain)

    2011-03-15

    Extensive analyses conducted by the European Community revealed that offshore wind energy have relatively benign effects on the marine environment by comparison to other forms of electric power generation [1]. However, the materials employed in offshore wind power farms suffer major changes to be confined to the marine environment at extreme conditions: saline medium, hydrostatic pressure... which can produce an important corrosion effect. This phenomenon can affect on the one hand, to the material from the structural viewpoint and on the other hand, to the marine environment. In this sense, to better understand the environmental impacts of generating electricity from offshore wind energy, this study evaluated the life cycle assessment for some new designs of submarine power cables developed by General Cable. To achieve this goal, three approaches have been carried out: leaching tests, eco-toxicity tests and Life Cycle Assessment (LCA) methodologies. All of them are aimed to obtaining quantitative data for environmental assessment of selected submarine cables. LCA is a method used to assess environmental aspects and potential impacts of a product or activity. LCA does not include financial and social factors, which means that the results of an LCA cannot exclusively form the basis for assessment of a product's sustainability. Leaching tests results allowed to conclude that pH of seawater did not significantly changed by the presence of submarine three-core cables. Although, it was slightly higher in case of broken cable, pH values were nearly equals. Concerning to the heavy metals which could migrate to the aquatic medium, there were significant differences in both scenarios. The leaching of zinc is the major environmental concern during undersea operation of undamaged cables whereas the fully sectioned three-core cable produced the migration of significant quantities of copper and iron apart from the zinc migrated from the galvanized steel. Thus, the tar

  14. Combining satellite-based fire observations and ground-based lightning detections to identify lightning fires across the conterminous USA

    Science.gov (United States)

    Bar-Massada, A.; Hawbaker, T.J.; Stewart, S.I.; Radeloff, V.C.

    2012-01-01

    Lightning fires are a common natural disturbance in North America, and account for the largest proportion of the area burned by wildfires each year. Yet, the spatiotemporal patterns of lightning fires in the conterminous US are not well understood due to limitations of existing fire databases. Our goal here was to develop and test an algorithm that combined MODIS fire detections with lightning detections from the National Lightning Detection Network to identify lightning fires across the conterminous US from 2000 to 2008. The algorithm searches for spatiotemporal conjunctions of MODIS fire clusters and NLDN detected lightning strikes, given a spatiotemporal lag between lightning strike and fire ignition. The algorithm revealed distinctive spatial patterns of lightning fires in the conterminous US While a sensitivity analysis revealed that the algorithm is highly sensitive to the two thresholds that are used to determine conjunction, the density of fires it detected was moderately correlated with ground based fire records. When only fires larger than 0.4 km2 were considered, correlations were higher and the root-mean-square error between datasets was less than five fires per 625 km2 for the entire study period. Our algorithm is thus suitable for detecting broad scale spatial patterns of lightning fire occurrence, and especially lightning fire hotspots, but has limited detection capability of smaller fires because these cannot be consistently detected by MODIS. These results may enhance our understanding of large scale patterns of lightning fire activity, and can be used to identify the broad scale factors controlling fire occurrence.

  15. A comparison of geospatially modeled fire behavior and fire management utility of three data sources in the southeastern United States

    Science.gov (United States)

    LaWen T. Hollingsworth; Laurie L. Kurth; Bernard R. Parresol; Roger D. Ottmar; Susan J. Prichard

    2012-01-01

    Landscape-scale fire behavior analyses are important to inform decisions on resource management projects that meet land management objectives and protect values from adverse consequences of fire. Deterministic and probabilistic geospatial fire behavior analyses are conducted with various modeling systems including FARSITE, FlamMap, FSPro, and Large Fire Simulation...

  16. Fire Safety

    Science.gov (United States)

    ... Whether the number is 911 or a regular phone number, everyone in the family should know it by ... near the phone. Include the local fire department phone number, your full home address and phone number, and ...

  17. Impacts of an underwater high voltage DC power cable on fish migration movements in the San Francisco Bay.

    Science.gov (United States)

    Wyman, M. T.; Kavet, R.; Klimley, A. P.

    2016-02-01

    There is an increasingly strong interest on a global scale in offshore renewable energy production and transportation. However, there is concern that the electromagnetic fields (EMF) produced by these underwater cables may alter the behavior and physiology of marine species. Despite this concern, few studies have investigated these effects in free-living species. In 2009, a 85 km long high-voltage DC (HVDC) power cable was placed within the San Francisco Bay, running parallel, then perpendicular to, the migration route of anadromous species moving from the inland river system to the oceans. In this study, we assess the impacts of this HVDC cable on the migration behaviors of EMF-sensitive fish, including juvenile salmonids (Chinook salmon, Oncorhynchus tshawytscha, and steelhead trout, Oncorhynchus mykiss) and adult green sturgeon, Acipenser medirostris. Acoustic telemetry techniques were used to track fish migration movements through the San Francisco Bay both before and after the cable was activated; individuals implanted with acoustic transmitters were detected on cross-channel hydrophone arrays at key locations in the system. Magnetic fields were surveyed and mapped at these locations using a transverse gradiometer, and models of the cable's magnetic field were developed that closely matched the empirically measured values. Here, we present our analyses on the relationships between migration-related behavioral metrics (e.g., percent of successful migrations, duration of migration, time spent near vs. far from cable location, etc.) and environmental parameters, such as cable activation and load level, local magnetic field levels, depth, and currents.

  18. Study of an YBCO HTS transmission cable system

    Energy Technology Data Exchange (ETDEWEB)

    Mukoyama, S. [Furukawa Electric Co., Ltd., Ecology and Energy Laboratory, 6, Yawata-Kaigandori, Ichihara, Chiba 290-8555 (Japan)], E-mail: mukoyama@ch.furukawa.co.jp; Yagi, M.; Hirano, N. [Furukawa Electric Co., Ltd., Ecology and Energy Laboratory, 6, Yawata-Kaigandori, Ichihara, Chiba 290-8555 (Japan); Amemiya, N. [Yokohama National University, Yokohama 240-8501 (Japan); Kashima, N.; Nagaya, S. [Chubu Electric Power Company, Nagoya 459-8522 (Japan); Izumi, T.; Shiohara, Y. [Superconductivity Research Laboratory, Tokyo 135-0062 (Japan)

    2007-10-01

    HTS transmission cables offer an innovative transmission line that differs from conventional technologies because HTS cables can send bulk power with extremely low loss. The HTS cable will contribute to energy saving and the prevention of global warming technologically. Reduction of cable loss is the most important development in economical cables for power networks. Today, second generation (2G) wires, such as an YBCO tape, are considered to have the potential to reduce AC loss. We developed YBCO power cables and succeeded in reducing AC loss to one-sixth the loss of BSCCO cable. According to our estimations, the total loss of an YBCO cable will be half the conventional (normal conducting) cable but yield the same power capacity.

  19. Characterization of fire regime in Sardinia (Italy)

    Science.gov (United States)

    Bacciu, V. M.; Salis, M.; Mastinu, S.; Masala, F.; Sirca, C.; Spano, D.

    2012-12-01

    In the last decades, a number of Authors highlighted the crucial role of forest fires within Mediterranean ecosystems, with impacts both negative and positive on all biosphere components and with reverberations on different scales. Fire determines the landscape structure and plant composition, but it is also the cause of enormous economic and ecological damages, beside the loss of human life. In Sardinia (Italy), the second largest island of the Mediterranean Basin, forest fires are perceived as one of the main environmental and social problems, and data are showing that the situation is worsening especially within the rural-urban peripheries and the increasing number of very large forest fires. The need for information concerning forest fire regime has been pointed out by several Authors (e.g. Rollins et al., 2002), who also emphasized the importance of understanding the factors (such as weather/climate, socio-economic, and land use) that determine spatial and temporal fire patterns. These would be used not only as a baseline to predict the climate change effect on forest fires, but also as a fire management and mitigation strategy. The main aim of this paper is, thus, to analyze the temporal and spatial patterns of fire occurrence in Sardinia (Italy) during the last three decades (1980-2010). For the analyzed period, fire statistics were provided by the Sardinian Forest Service (CFVA - Corpo Forestale e di Vigilanza Ambientale), while weather data for eight weather stations were obtained from the web site www.tutiempo.it. For each station, daily series of precipitation, mean, maximum and minimum temperature, relative humidity and wind speed were available. The present study firstly analyzed fire statistics (burned area and number of fires) according to the main fire regime characteristics (seasonality, fire return interval, fire incidence, fire size distribution). Then, fire and weather daily values were averaged to obtain monthly, seasonal and annual values, and

  20. Making fire and fire surrogate science available: a summary of regional workshops with clients

    Science.gov (United States)

    Andrew Youngblood; Heidi Bigler-Cole; Christopher J. Fettig; Carl Fiedler; Eric E. Knapp; John F. Lehmkuhl; Kenneth W. Outcalt; Carl N. Skinner; Scott L. Stephens; Thomas A. Waldrop

    2007-01-01

    Operational-scale experiments that evaluate the consequences of fire and mechanical "surrogates" for natural disturbance events are essential to better understand strategies for reducing the incidence and severity of wildfire. The national Fire and Fire Surrogate (FFS) study was initiated in 1999 to establish an integrated network of long-term studies...

  1. Application study on the first cable-stayed bridge with CFRP cables in China

    Directory of Open Access Journals (Sweden)

    Kuihua Mei

    2015-08-01

    Full Text Available In order to push forward the development of CFRP cable-stayed bridge and accumulate experiences, the study on the application of the first cable-stayed bridge with CFRP cables in China was carried out. The design essentials of main components of the bridge were introduced and its integral performances, including static properties, dynamic properties and seismic response were analyzed using finite element method. A new bond-type anchorage was developed and the processes of fabricating and installing CFRP cables were elaborated. Based on the results of construction simulation, a tension scheme for bridge was propound. During constructing, the stresses and displacement of girder and pylon, as well as the forces and stresses of cables, were tested. The results indicate that all sections of the bridge could meet the requirements of the ultimate bearing capacity and normal service; the performance of the anchorage is good and the stresses in each cable system are similar; the tested values accord well with the calculated values. Further, creep deformation of the resin in anchorages under service load is not obvious. All these results demonstrate that the first application of CFRP cables in the cable-stayed bridge in China is successful.

  2. A comparison of three approaches for simulating fine-scale surface winds in support of wildland fire management. Part II. An exploratory study of the effect of simulated winds on fire growth simulations

    Science.gov (United States)

    Jason M. Forthofer; Bret W. Butler; Charles W. McHugh; Mark A. Finney; Larry S. Bradshaw; Richard D. Stratton; Kyle S. Shannon; Natalie S. Wagenbrenner

    2014-01-01

    The effect of fine-resolution wind simulations on fire growth simulations is explored. The wind models are (1) a wind field consisting of constant speed and direction applied everywhere over the area of interest; (2) a tool based on the solution of the conservation of mass only (termed mass-conserving model) and (3) a tool based on a solution of conservation of mass...

  3. Applying Diagnostics to Enhance Cable System Reliability (Cable Diagnostic Focused Initiative, Phase II)

    Energy Technology Data Exchange (ETDEWEB)

    Hartlein, Rick [Georgia Tech Research Corporation (GTRC), Atlanta, GA (United States). National Electric Energy Testing, Research and Applications Center (NEETRAC); Hampton, Nigel [Georgia Tech Research Corporation (GTRC), Atlanta, GA (United States). National Electric Energy Testing, Research and Applications Center (NEETRAC); Perkel, Josh [Georgia Tech Research Corporation (GTRC), Atlanta, GA (United States). National Electric Energy Testing, Research and Applications Center (NEETRAC); Hernandez, JC [Univ. de Los Andes, Merida (Venezuela); Elledge, Stacy [Georgia Tech Research Corporation (GTRC), Atlanta, GA (United States). National Electric Energy Testing, Research and Applications Center (NEETRAC); del Valle, Yamille [Georgia Tech Research Corporation (GTRC), Atlanta, GA (United States). National Electric Energy Testing, Research and Applications Center (NEETRAC); Grimaldo, Jose [Georgia Inst. of Technology, Atlanta, GA (United States). School of Electrical and Computer Engineering; Deku, Kodzo [Georgia Inst. of Technology, Atlanta, GA (United States). George W. Woodruff School of Mechanical Engineering

    2016-02-01

    The Cable Diagnostic Focused Initiative (CDFI) played a significant and powerful role in clarifying the concerns and understanding the benefits of performing diagnostic tests on underground power cable systems. This project focused on the medium and high voltage cable systems used in utility transmission and distribution (T&D) systems. While many of the analysis techniques and interpretations are applicable to diagnostics and cable systems outside of T&D, areas such as generating stations (nuclear, coal, wind, etc.) and other industrial environments were not the focus. Many large utilities in North America now deploy diagnostics or have changed their diagnostic testing approach as a result of this project. Previous to the CDFI, different diagnostic technology providers individually promoted their approach as the “the best” or “the only” means of detecting cable system defects.

  4. Test matrices for evaluating cable median barriers placed in v-ditches.

    Science.gov (United States)

    2012-07-01

    Cable barrier systems designed to be used in median ditches have been traditionally full-scale crash tested placed either : within 4 ft from the slope break point (SBP) of a 4H:1V front slope or near the bottom of the ditch. Recently, there has been ...

  5. Holocene fire dynamics in Fennoscandia

    Science.gov (United States)

    Clear, Jennifer; Seppa, Heikki; Kuosmanen, Niina; Molinari, Chiara; Lehsten, Veiko; Allen, Katherine; Bradshaw, Richard

    2015-04-01

    Prescribed burning is advocated in Fennoscandia to promote regeneration and to encourage biodiversity. This method of forest management is based on the perception that fire was much more frequent in the recent past and over a century of active fire suppression has created a boreal forest ecosystem almost free of natural fire. The absence of fire is thought to have contributed to the widespread dominance of Picea abies (Norway spruce) with the successive spruce dominated forest further reducing fire ignition potential. However, humans have altered the natural fire dynamics of Fennoscandia since the early- to mid-Holocene and disentangling the anthropogenic driven fire dynamics from the natural fire dynamics is challenging. Through palaeoecology and sedimentary charcoal deposits we are able to explore the Holocene spatial and temporal variability and changing drivers of fire and vegetation dynamics in Fennoscandia. At the local-scale, two forest hollow environments (analysed for high resolution macroscopic charcoal and pollen analysis and their fire and vegetation history are compared to identify unique and mutual changes in disturbance history. Pollen derived quantitative reconstruction of vegetation at both the local- and regional-scale identifies local-scale disturbance dynamics and large-scale ecosystem response. Spatio-temporal heterogeneity and variability in biomass burning is explored throughout Fennoscandia and Denmark to identify the changing drives of fire dynamics throughout the Holocene. Palaeo-vegetation reconstructions are compared to process-based, climate driven dynamic vegetation model output to test the significance of fire frequency as a driver of vegetation composition and dynamics. Early-Holocene fire regimes in Fennoscandia are driven by natural climate variations and fuel availability. The establishment and spread of Norway spruce is driven by an increase in continentality of climate, but local natural and anthropogenic ecosystem disturbance

  6. Evaluation of cable ageing in Nuclear Power Plants; Evaluacion del envejecimiento de cables en centrales nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Vergara, T. [Empresarios Agrupados, A. I. E. Madrid (Spain); Alonso Chicote, J. [TECNATOM, S. A. (Spain); Burnay, S. [AEA Technology (UK)

    2000-07-01

    The majority of power, control and instrumentation cables in nuclear power plants use polymers as their basic material for insulation and jacket. In many cases, these cables form part of safety-related circuits and should therefore be capable of operating correctly under both normal and accident conditions. Since polymeric materials are degraded by the long term action of the radiation and thermal environments found in the plant, it is important to be able to establish the cable condition during the plant lifetime. Nowadays there are a number of different methods to evaluate the remaining lifetime of cables. In the case of new plants, or new cables in old plants, accelerated ageing tests and predictive models can be used to establish the behaviour of the cable materials under operating conditions. There are verified techniques and considerable experience in the definition of predictive models. This type of approach is best carried out during the commissioning stage or in the early stages of operation. In older plants, particularly where there is a wide range of cable types in use, it is more appropriate to use condition monitoring methods to establish the state of degradation of cables in-plant. Over the last 10 years there have been considerable developments in methods for condition monitoring of cables and a tool-box of practical techniques are now available. There is no single technique which is suitable for all cable materials but the range of methods covers nearly all of the types currently in use, at present, the most established methods are the indented, thermal analysis (OIT, OITP and TGA) and dielectric loss measurements, All of these are either non-destructive methods or require only micro-samples of material. (Author) 15 refs.

  7. High voltage pulsed cable design: a practical example

    Energy Technology Data Exchange (ETDEWEB)

    Kewish, R.W. Jr.; Boicourt, G.P.

    1979-01-01

    The design of optimum high voltage pulse cable is difficult because very little emperical data are available on performance in pulsed applications. This paper follows the design and testing of one high voltage pulse cable, 40/100 trigger cable. The design was based on an unproven theory and the impressive outcome lends support to the theory. The theory is outlined and it is shown that there exists an inductance which gives a cable of minimum size for a given maximum stress. Test results on cable manufactured according to the design are presented and compared with the test results on the cable that 40/100 replaces.

  8. Energy losses of superconducting power transmission cables in the grid

    DEFF Research Database (Denmark)

    Østergaard, Jacob; Okholm, Jan; Lomholt, Karin

    2001-01-01

    One of the obvious motives for development of superconducting power transmission cables is reduction of transmission losses. Loss components in superconducting cables as well as in conventional cables have been examined. These losses are used for calculating the total energy losses of conventional...... as well as superconducting cables when they are placed in the electric power transmission network. It is concluded that high load connections are necessary to obtain energy saving by the use of HTSC cables. For selected high load connections, an energy saving of 40% is expected. It is shown...... that the thermal insulation and cooling machine efficiency are the most important loss element in a superconducting cable system...

  9. Stability Measurements of Rutherford Cables with Various Treatments

    CERN Document Server

    Kim, S W; Wilson, M N; Ghosh, A; Sampson, W B

    1999-01-01

    To improve the stability of Rutherford type superconducting cables, various methods of treating cables were considered and tested. These treatments include strand coating, partial soldering, "barber-pole" insulation and "porous $9 metal" solder filling. To study the effect of these treatments, several cables were prepared and MQE (minimum quench energy) values were measured. Coating, partial soldering or "barber-pole insulation" improved the relative stability $9 for some cables. The "porous metal" filled cables showed higher MQE. However the results suggest that the porous metal process needs to be improved. The measured data for cables with various treatments are presented. (8 refs).

  10. How a new fire-suppression policy can abruptly reshape the fire-weather relationship

    OpenAIRE

    Ruffault, J.; Mouillot, Florent

    2015-01-01

    Understanding how the interactions between anthropogenic and biophysical factors control fire regimes is increasingly becoming a major concern in a context of climate, economic and social changes. On a short time scale, fire activity is mainly driven by the variations in weather conditions. But while the assessment of this fire-weather relationship is an essential step towards fire hazard estimations, reconstructions or projections, still little is known about the impact of human practices on...

  11. Noise and vibration investigations of the Sandia National Laboratories Sol se Mete Aerial Cable Facility

    Energy Technology Data Exchange (ETDEWEB)

    Matise, B.K.; Gutman, W.M.; Cunniff, R.A.; Silver, R.J.; Stepp, W.E. [New Mexico State Univ., Las Cruces, NM (United States). Physical Science Lab.

    1994-11-01

    This document is an assessment of the noise, vibration, and overpressure effects and fragmentation hazards of the operation of the Sandia National Laboratories Sol de Mete Aerial Cable Facility (ACF). Major noise sources associated with project operations and considered in this report include rocket motors, chemical explosions, 3-inch gun, 20-mm gun, vehicular traffic, and engines of electricity generators. In addition, construction equipment noise is considered. Noise exposure of ACF personnel is expressed as the equivalent sound level for the 8-hour work day, and is computed by scaling to the proper distance and combining the appropriate noise values for continuously operating equipment such as vehicles and generators. Explosions and gun firings are impulsive events, and overpressures are predicted and expressed as decibel (dB) at the control building, at other nearby facilities, at Sol se Mete. The conclusion reached in the noise analysis is that continuously operating equipment would not produce a serious noise hazard except in the immediate vicinity of the electricity generators and heavy equipment where hearing protection devices should be used. Rocket motors, guns, and detonations of less than 54 kilograms (kg) (120 lb) of explosives would not produce noise levels above the threshold for individual protection at the control building, other nearby test areas, or Sol se Mete Spring. Rare tests involving explosive weights between 54 and 454 kg (120 and 1,000 lb) could produce impulsive noise levels above 140 dB that would require evacuation or other provision for individual hearing protection at the ACF control building and at certain nearby facilities not associated with ACF. Other blast effects including overpressure, ground vibration, and fragmentation produce hazard radii that generally are small than the corresponding noise hazard radius, which is defined as the distance at which the predicted noise level drops to 140 dB.

  12. Development of innovative superconducting DC power cable

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, Teruo; Kiuchi, Masaru [Dept. of Computer Science and Electronics Kyushu Institute of Technology, Iizuka (Japan)

    2017-09-15

    It is required to reduce the cost of superconducting cable to realize a superconducting DC power network that covers a wide area in order to utilize renewable energy. In this paper a new concept of innovative cable is introduced that can enhance the current-carrying capacity even though the same superconducting tape is used. Such a cable can be realized by designing an optimal winding structure in such a way that the angle between the tape and magnetic field becomes small. This idea was confirmed by preliminary experiments for a single layer model cable made of Bi-2223 tapes and REBCO coated conductors. Experiments of three and four layer cables of practical sizes were also done and it was found that the current-carrying capacity increased as theoretically predicted. If the critical current properties of commercial superconducting tapes are further improved in a parallel magnetic field, the enhancement will become pronounced and this technology will surely contribute to realization of superconducting DC power network.

  13. Coaxial cable distribution plant performance simulation

    Science.gov (United States)

    Carangi, Mark D.; Chen, Walter Y.; Kerpez, Kenneth J.; Valenti, Craig F.

    1995-11-01

    The CATV system delivers analog video signals from a centralized headend through a tree- and-branch fiber/coax network. That architecture is very cost effective for delivering broadcast video channels to a vast area. The introduction of interactive TV, data and telephony services requires an upstream link from customers to the headend. Although equipment for upstream transmission is available, CATV systems are primarily engineered for the delivery of one way analog broadcast TV programs. In this paper, issues related to two-way digital transmission through the coaxial cable distribution plant are examined. The objective is to establish a reliable computer modeling environment for the study and simulation of general and advanced transmission systems over the coaxial cable distribution plant. The discussions are focused on three general topics: the coaxial cable distribution plant transmission channel, the corresponding noise environment, and applicable transmission system architectures. Two- port network models are developed for the components (coaxial cable, taps, etc.) of the coaxial cable distribution plant. A realistic distribution plant channel model can be constructed based on these component models. The distribution plant noise level is analyzed based on thermal noise level, amplifier noise figure, and the funneling effect. The upstream ingress noise model is also developed. Three advanced transmission systems, adaptive transmitter, frame based equalization, and discrete multitone (DMT), are presented. End to end computer simulation results are presented using QPSK upstream.

  14. The glass story: fibre optic cable

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2000-12-01

    Fibre optic cable has become the glamour pinup among cables as a result of its ability to carry billions of digital bits of information per second. Fibre optic cables consist of hair-thin fibres of high purity silica glass; enclosed in its protective shield and glass cladding, the cable is immune to electromagnetic interference and carries out its task without the need for boosting. It is the perfect answer to the ever-increasing need for speed and capacity of today's high-speed computers. This paper describes the nature of fibre optics, the two major optical fibre categories of multi-mode and single-mode, and the various possible applications for each type. Although the optical performance of fibres is relatively standardized regardless of the manufacturer, physical characteristics do vary across the industry. Fibre type and fibre parameters are usually defined by the transmission system application, whereas the cable design is usually determined by the physical environment of the particular installation. 1 tab., 5 figs.

  15. Test-based approach to cable tray support system analysis and design: Behavior and test methods

    Energy Technology Data Exchange (ETDEWEB)

    Reigles, Damon G., E-mail: dreigles@engnovex.com [engNoveX, Inc., 19C Trolley Square, Wilmington, DE 19806 (United States); Brachmann, Ingo; Johnson, William H. [Bechtel Nuclear, Security & Environmental, 12011 Sunset Hills Rd, Suite 110, Reston, VA 20190 (United States); Gürbüz, Orhan [Tobolski Watkins Engineering, Inc., 4125 Sorrento Valley Blvd, Suite B, San Diego, CA 92121 (United States)

    2016-06-15

    Highlights: • Describes dynamic response behavior of unistrut type cable tray supports. • Summarizes observations from past full-scale shake table test programs. • Outlines testing methodologies necessary to identify key system parameters. - Abstract: Nuclear power plant safety-related cable tray support systems subjected to seismic loadings were originally understood and designed to behave as linear elastic systems. This behavioral paradigm persisted until the early 1980s when, due to evolution of regulatory criteria, some as-installed systems needed to be qualified to higher seismic motions than originally designed for. This requirement prompted a more in-depth consideration of the true seismic response behavior of support systems. Several utilities initiated extensive test programs, which demonstrated that trapeze strut-type cable tray support systems exhibited inelastic and nonlinear response behaviors with plastic hinging at the connections together with high damping due to bouncing of cables in the trays. These observations were used to demonstrate and justify the seismic adequacy of the aforementioned as-installed systems. However, no formalized design methodology or criteria were ever established to facilitate use of these test data for future evaluations. This paper assimilates and reviews the various test data and conclusions for the purpose of developing a design methodology for the seismic qualification of safety-related cable tray support systems.

  16. Full-scale ash deposition measurements at Avedøre Power Plant unit 2 during suspension-firing of wood with and without coal ash addition

    DEFF Research Database (Denmark)

    Wu, Hao; Shafique Bashir, Muhammad; Jensen, Peter Arendt

    addition on deposit formation during wood suspension-firing at AVV2 was evaluated. It was revealed that the addition of coal fly ash could significantly influence the ash deposition/shedding behaviors and the deposit properties. The effect was evident at both measurement locations. At the location......The formation of deposits during suspension-firing of wood at Avedøre Power Plant unit 2 (AVV2) was studied by using an advanced deposit probe system. The tests were conducted both with and without coal ash addition, and at two different locations with flue gas temperatures of 1250-1300 oC and 750...

  17. Assessing the influence of small fires on trends in fire regime features at mainland Spain

    Science.gov (United States)

    Jiménez-Ruano, Adrián; Rodrigues Mimbrero, Marcos; de la Riva Fernández, Juan

    2017-04-01

    Small fires, i.e. fires smaller than 1 Ha, represent a huge proportion of total wildfire occurrence in the Mediterranean region. In the case of Spain, around 53% of fires in the period 1988-2013 fall into this category according to the Spanish EGIF statistics. However, the proportion of small fires is not stationary over time. Small fires are usually excluded from most analysis, given the chance of introducing or falling into temporal bias, being almost mandatory in those assessments using data before the 90s. Inconsistences and inhomogeneity problems related to the diversity of criteria and/or registration procedures among Autonomous Regions are found before that date, although it is widely agreed that small fires are consistently registered starting from 1988. Nevertheless, in terms of fire regimen characterization it is important to know to what extent small fires contribute to the overall fire behaviour. The aim of this study is to analyse spatial-temporal trends of several fire features such as total number of fires and burned area, number and burned area of natural and human fires, and the proportion of natural/human cause in the period 1988-2013 at province level (NUTS3). The analysis is conducted at the mainland Spain at annual and seasonal time scales. We are mainly interested in exploring differences in spatial-temporal trends including or excluding small fires and dealing with them separately as well. This allows determining the extent to which small fires may affect fire regime characterization. We employed a Mann-Kendall test for trend detection and Sen's slope to evaluate the magnitude of the change. Both tests were applied for each fire feature aggregated at NUTS3 level for both autumn-winter and spring-summer seasons. Our results show significant changes in the evolution of annual wildfire frequency; especially strong when small fires are accounted for. A similar outcome was observed in natural and human number fires during the spring-summer season

  18. Determination of aerodynamic damping of twin cables in wet conditions through passive-dynamic wind tunnel tests

    DEFF Research Database (Denmark)

    Eriksen, Mads Beedholm; Mattiello, E.; Georgakis, Christos T.

    2013-01-01

    operational modal analysis of the monitored vibrations revealed, in certain conditions and for specific wind velocities, the presence of negative aerodynamic damping.To investigate the observed aerodynamic damping of the twin cable arrangement further, a series of 1:2.3 scale passive-dynamic wind tunnel tests...... of the bridge cables. For the wet tests, the twin cable surfaces were treated in order to obtain uniform upper and lower water rivulets. The interaction between water rivulets, surface properties and the flow was found to govern the activation of the RWIV mechanism. The resulting aerodynamic damping from wet...... passive-dynamic wind tunnel tests showed the effect of the helical fillets in preventing the occurrence of negative aerodynamic damping, contrary to the plain cables. © 2013 Taylor & Francis Group, London, UK....

  19. Seasonality of Fire Weather Strongly Influences Fire Regimes in South Florida Savanna-Grassland Landscapes

    Science.gov (United States)

    Platt, William J.; Orzell, Steve L.; Slocum, Matthew G.

    2015-01-01

    Fire seasonality, an important characteristic of fire regimes, commonly is delineated using seasons based on single weather variables (rainfall or temperature). We used nonparametric cluster analyses of a 17-year (1993–2009) data set of weather variables that influence likelihoods and spread of fires (relative humidity, air temperature, solar radiation, wind speed, soil moisture) to explore seasonality of fire in pine savanna-grassland landscapes at the Avon Park Air Force Range in southern Florida. A four-variable, three-season model explained more variation within fire weather variables than models with more seasons. The three-season model also delineated intra-annual timing of fire more accurately than a conventional rainfall-based two-season model. Two seasons coincided roughly with dry and wet seasons based on rainfall. The third season, which we labeled the fire season, occurred between dry and wet seasons and was characterized by fire-promoting conditions present annually: drought, intense solar radiation, low humidity, and warm air temperatures. Fine fuels consisting of variable combinations of pyrogenic pine needles, abundant C4 grasses, and flammable shrubs, coupled with low soil moisture, and lightning ignitions early in the fire season facilitate natural landscape-scale wildfires that burn uplands and across wetlands. We related our three season model to fires with different ignition sources (lightning, military missions, and prescribed fires) over a 13-year period with fire records (1997–2009). Largest wildfires originate from lightning and military ignitions that occur within the early fire season substantially prior to the peak of lightning strikes in the wet season. Prescribed ignitions, in contrast, largely occur outside the fire season. Our delineation of a pronounced fire season provides insight into the extent to which different human-derived fire regimes mimic lightning fire regimes. Delineation of a fire season associated with timing of

  20. Seasonality of fire weather strongly influences fire regimes in South Florida savanna-grassland landscapes.

    Directory of Open Access Journals (Sweden)

    William J Platt

    Full Text Available Fire seasonality, an important characteristic of fire regimes, commonly is delineated using seasons based on single weather variables (rainfall or temperature. We used nonparametric cluster analyses of a 17-year (1993-2009 data set of weather variables that influence likelihoods and spread of fires (relative humidity, air temperature, solar radiation, wind speed, soil moisture to explore seasonality of fire in pine savanna-grassland landscapes at the Avon Park Air Force Range in southern Florida. A four-variable, three-season model explained more variation within fire weather variables than models with more seasons. The three-season model also delineated intra-annual timing of fire more accurately than a conventional rainfall-based two-season model. Two seasons coincided roughly with dry and wet seasons based on rainfall. The third season, which we labeled the fire season, occurred between dry and wet seasons and was characterized by fire-promoting conditions present annually: drought, intense solar radiation, low humidity, and warm air temperatures. Fine fuels consisting of variable combinations of pyrogenic pine needles, abundant C4 grasses, and flammable shrubs, coupled with low soil moisture, and lightning ignitions early in the fire season facilitate natural landscape-scale wildfires that burn uplands and across wetlands. We related our three season model to fires with different ignition sources (lightning, military missions, and prescribed fires over a 13-year period with fire records (1997-2009. Largest wildfires originate from lightning and military ignitions that occur within the early fire season substantially prior to the peak of lightning strikes in the wet season. Prescribed ignitions, in contrast, largely occur outside the fire season. Our delineation of a pronounced fire season provides insight into the extent to which different human-derived fire regimes mimic lightning fire regimes. Delineation of a fire season associated with

  1. Seasonality of fire weather strongly influences fire regimes in South Florida savanna-grassland landscapes.

    Science.gov (United States)

    Platt, William J; Orzell, Steve L; Slocum, Matthew G

    2015-01-01

    Fire seasonality, an important characteristic of fire regimes, commonly is delineated using seasons based on single weather variables (rainfall or temperature). We used nonparametric cluster analyses of a 17-year (1993-2009) data set of weather variables that influence likelihoods and spread of fires (relative humidity, air temperature, solar radiation, wind speed, soil moisture) to explore seasonality of fire in pine savanna-grassland landscapes at the Avon Park Air Force Range in southern Florida. A four-variable, three-season model explained more variation within fire weather variables than models with more seasons. The three-season model also delineated intra-annual timing of fire more accurately than a conventional rainfall-based two-season model. Two seasons coincided roughly with dry and wet seasons based on rainfall. The third season, which we labeled the fire season, occurred between dry and wet seasons and was characterized by fire-promoting conditions present annually: drought, intense solar radiation, low humidity, and warm air temperatures. Fine fuels consisting of variable combinations of pyrogenic pine needles, abundant C4 grasses, and flammable shrubs, coupled with low soil moisture, and lightning ignitions early in the fire season facilitate natural landscape-scale wildfires that burn uplands and across wetlands. We related our three season model to fires with different ignition sources (lightning, military missions, and prescribed fires) over a 13-year period with fire records (1997-2009). Largest wildfires originate from lightning and military ignitions that occur within the early fire season substantially prior to the peak of lightning strikes in the wet season. Prescribed ignitions, in contrast, largely occur outside the fire season. Our delineation of a pronounced fire season provides insight into the extent to which different human-derived fire regimes mimic lightning fire regimes. Delineation of a fire season associated with timing of

  2. Electrothermal Coordination in Cable Based Transmission Grids

    DEFF Research Database (Denmark)

    Olsen, Rasmus Schmidt; Holbøll, Joachim; Gudmundsdottir, Unnur Stella

    2013-01-01

    behavior of the components. The dynamic temperature calculations of power cables are suggested to be based on thermoelectric equivalents (TEEs). It is shown that the thermal behavior can be built into widely used load flow software, creating a strong ETC tool. ETC is, through two case scenarios, proven......Electrothermal coordination (ETC) is introduced for cable based transmission grids. ETC is the term covering operation and planning of transmission systems based on temperature, instead of current. ETC consists of one part covering the load conditions of the system and one covering the thermal...... to be beneficial for both operator and system planner. It is shown how the thermal behavior can be monitored in real-time during normal dynamic load and during emergencies. In that way, ETC enables cables to be loaded above their normal rating, while maintaining high reliability of the system, which potentially...

  3. Computer-Aided Engineering Of Cabling

    Science.gov (United States)

    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

  4. Distance and Cable Length Measurement System

    Science.gov (United States)

    Hernández, Sergio Elias; Acosta, Leopoldo; Toledo, Jonay

    2009-01-01

    A simple, economic and successful design for distance and cable length detection is presented. The measurement system is based on the continuous repetition of a pulse that endlessly travels along the distance to be detected. There is a pulse repeater at both ends of the distance or cable to be measured. The endless repetition of the pulse generates a frequency that varies almost inversely with the distance to be measured. The resolution and distance or cable length range could be adjusted by varying the repetition time delay introduced at both ends and the measurement time. With this design a distance can be measured with centimeter resolution using electronic system with microsecond resolution, simplifying classical time of flight designs which require electronics with picosecond resolution. This design was also applied to position measurement. PMID:22303169

  5. Distance and Cable Length Measurement System

    Directory of Open Access Journals (Sweden)

    Jonay Toledo

    2009-12-01

    Full Text Available A simple, economic and successful design for distance and cable length detection is presented. The measurement system is based on the continuous repetition of a pulse that endlessly travels along the distance to be detected. There is a pulse repeater at both ends of the distance or cable to be measured. The endless repetition of the pulse generates a frequency that varies almost inversely with the distance to be measured. The resolution and distance or cable length range could be adjusted by varying the repetition time delay introduced at both ends and the measurement time. With this design a distance can be measured with centimeter resolution using electronic system with microsecond resolution, simplifying classical time of flight designs which require electronics with picosecond resolution. This design was also applied to position measurement.

  6. Fire Safety (For Parents)

    Science.gov (United States)

    ... of Braces Eating Disorders Mitral Valve Prolapse Arrhythmias Fire Safety KidsHealth > For Parents > Fire Safety Print A ... event of a fire emergency in your home. Fire Prevention Of course, the best way to practice ...

  7. Fire Research Enclosure

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Simulates submarine fires, enclosed aircraft fires, and fires in enclosures at shore facilities .DESCRIPTION: FIRE I is a pressurizable, 324 cu m(11,400 cu...

  8. Active Fire Mapping Program

    Science.gov (United States)

    Active Fire Mapping Program Current Large Incidents (Home) New Large Incidents Fire Detection Maps MODIS Satellite Imagery VIIRS Satellite Imagery Fire Detection GIS Data Fire Data in Google Earth ...

  9. Modeling topographic influences on fuel moisture and fire danger in complex terrain to improve wildland fire management decision support

    Science.gov (United States)

    Zachary A. Holden; W. Matt Jolly

    2011-01-01

    Fire danger rating systems commonly ignore fine scale, topographically-induced weather variations. These variations will likely create heterogeneous, landscape-scale fire danger conditions that have never been examined in detail. We modeled the evolution of fuel moistures and the Energy Release Component (ERC) from the US National Fire Danger Rating System across the...

  10. A comparison of three approaches for simulating fine-scale surface winds in support of wildland fire management: Part I. Model formulation and comparison against measurements

    Science.gov (United States)

    Jason M. Forthofer; Bret W. Butler; Natalie S. Wagenbrenner

    2014-01-01

    For this study three types of wind models have been defined for simulating surface wind flow in support of wildland fire management: (1) a uniform wind field (typically acquired from coarse-resolution (,4 km) weather service forecast models); (2) a newly developed mass-conserving model and (3) a newly developed mass and momentumconserving model (referred to as the...

  11. Impact of Coal Fly Ash Addition on Combustion Aerosols (PM2.5) from Full-Scale Suspension-Firing of Pulverized Wood

    DEFF Research Database (Denmark)

    Damø, Anne Juul; Wu, Hao; Frandsen, Flemming

    2014-01-01

    The formation of combustion aerosols was studied in an 800 MWth suspension-fired power plant boiler, during combustion of pulverized wood pellets with and without addition of coal fly ash as alkali capture additive. The aerosol particles were sampled and characterized by a low-pressure cascade im...

  12. Benefits of coal-fired power generation with flexible CCS in a future northwest European power system with large scale wind power

    NARCIS (Netherlands)

    Van der Wijk, Pieter Cornelis; Brouwer, Anne Sjoerd|info:eu-repo/dai/nl/330822748; Van den Broek, Machteld|info:eu-repo/dai/nl/092946895; Slot, Thijs; Stienstra, Gerard; Van der Veen, Wim; Faaij, André P C

    Coal-fired power generation with carbon capture and storage (CCS) is projected as a cost-effective technology to decarbonize the power sector. Intermittent renewables could reduce its load factor and revenues, so flexible capture unit operation strategies (flexible CCS) have been suggested to

  13. Pinus halepensis M. versus Quercus ilex subsp. Rotundifolia L. runoff and soil erosion at pedon scale under natural rainfall in Eastern Spain three decades after a forest fire

    NARCIS (Netherlands)

    Cerdà, Artemi; Lucas Borja, Manuel Esteban; Úbeda, Xavier; Martínez-Murillo, Juan Francisco; Keesstra, Saskia

    2017-01-01

    Afforestation aims to recover the vegetation cover, and restore natural ecosystems. The plant species selected for restoration will determine species richness and the fate of the ecosystem. Research focussing on the impact of vegetation recovery on soil quality are abundant, especially on fire

  14. Analysis of Electrical Coupling Parameters in Superconducting Cables

    CERN Document Server

    Bottura, L; Rosso, C

    2003-01-01

    The analysis of current distribution and redistribution in superconducting cables requires the knowledge of the electric coupling among strands, and in particular the interstrand resistance and inductance values. In practice both parameters can have wide variations in cables commonly used such as Rutherford cables for accelerators or Cable-in-Conduits for fusion and SMES magnets. In this paper we describe a model of a multi-stage twisted cable with arbitrary geometry that can be used to study the range of interstrand resistances and inductances that is associated with variations of geometry. These variations can be due to cabling or compaction effects. To describe the variations from the nominal geometry we have adopted a cable model that resembles to the physical process of cabling and compaction. The inductance calculation part of the model is validated by comparison to semi-analytical results, showing excellent accuracy and execution speed.

  15. Energy analysis of vehicle-to-cable barrier impacts.

    Science.gov (United States)

    2013-06-01

    An accident reconstruction technique was developed for estimating the energy absorbed during an impact with a cable barrier system as well as the initial impact velocity. The kinetic energy absorbed during a cable barrier system impact is comprised o...

  16. Superconducting power cables in Denmark - a case study

    DEFF Research Database (Denmark)

    Østergaard, Jacob

    1997-01-01

    that HTS cables will be less expensive for high power ratings, have lower losses for lines with a high load, and have a reduced reactive power production. The use of superconducting cables in Denmark accommodate plans by the Danish utility to make a substantial conversion of overhead lines to underground......A case study of a 450 MVA, 132 kV high temperature superconducting (HTS) power transmission cable has been carried out. In the study, a superconducting cable system is compared to a conventional cable system which is under construction for an actual transmission line in the Danish grid. The study...... considers the design and development of a calculation model for an HTS cable system including auxiliary facilities. From calculations of the selected transmission line, conclusions on the feasibility of HTS cables in Denmark are made. HTS cables appear to be feasible in Denmark. Calculations indicate...

  17. Modeling of the power cable production line

    Energy Technology Data Exchange (ETDEWEB)

    Kosar, Vanja; Gomzi, Zoran [Faculty of Chemical Engineering and Technology, Department of Reaction Engineering and Catalysis, University of Zagreb, Savska c. 16, HR-10000 Zagreb (Croatia)

    2007-06-15

    During the manufacturing of a power cable insulated with the cross-linkable polyethylene, the hot polymer is applied to the conductor by extrusion, below temperatures of the rapid cross-linking. The coated cable passes into a high-pressure tube (filled with nitrogen under the pressure of 10 bar) in order to heat up the insulation to temperatures at which the cross-linking agent is highly active. This is the continuous vulcanization (CV) tube. Changes of process variables associated with the CV tube can cause changes in the physical properties, the aging characteristics, and especially the heat resistance of the cable insulation. Performance of insulating compounds in this area of the cross-linking process can determine maximum output rates of a power cable manufacturing facility. The mathematical model describes cross-linking process in the vulcanization tube, which is in fact a tubular reactor. In the vulcanization tube heat is transferred by convection, conduction and radiation. Also, the reaction heat is liberated by the chemical reaction and the heat balance describes all four impacts. Formal part of the mathematical model is a material balance that describes the reactions kinetics. Heat and mole balance are connected with reaction rate and mathematically present a system of partial differential equations which will be numerically solved for chosen boundary conditions, both for the reaction part and for the cooling part of a process. On the basis of the real process parameters and the presented mathematical model simulation of the process was conducted. From the presented simulation the optimal process parameters such as process temperatures, cable linear velocity (u) and cable cooling properties of CV line are predicted and evaluated. (author)

  18. Measurements relating fire radiative energy density and surface fuel consumption - RxCADRE 2011 and 2012

    Science.gov (United States)

    Andrew T. Hudak; Matthew B. Dickinson; Benjamin C. Bright; Robert L. Kremens; E. Louise Loudermilk; Joseph J. O' Brien; Benjamin S. Hornsby; Roger D. Ottmar

    2016-01-01

    Small-scale experiments have demonstrated that fire radiative energy is linearly related to fuel combusted but such a relationship has not been shown at the landscape level of prescribed fires. This paper presents field and remotely sensed measures of pre-fire fuel loads, consumption, fire radiative energy density (FRED) and fire radiative power flux density (FRFD),...

  19. Issues in Numerical Simulation of Fire Suppression

    Energy Technology Data Exchange (ETDEWEB)

    Tieszen, S.R.; Lopez, A.R.

    1999-04-12

    This paper outlines general physical and computational issues associated with performing numerical simulation of fire suppression. Fire suppression encompasses a broad range of chemistry and physics over a large range of time and length scales. The authors discuss the dominant physical/chemical processes important to fire suppression that must be captured by a fire suppression model to be of engineering usefulness. First-principles solutions are not possible due to computational limitations, even with the new generation of tera-flop computers. A basic strategy combining computational fluid dynamics (CFD) simulation techniques with sub-grid model approximations for processes that have length scales unresolvable by gridding is presented.

  20. Fire analysis. Relevant aspects from Spanish nuclear power plants experience

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Pedro; Villar, Tomas [Empresarios Agrupados A.I.E., Madrid (Spain). Nuclear Safety Dept.

    2015-12-15

    Empresarios Agrupados A.I.E. leads the development and updating of fire analysis for the Spanish NPP's. Some of them decided to voluntarily adopt standard NFPA-805 as an alternative to the current fire protection rules. Fire Probabilistic Risk Assessment (PRA) methodologies have been continuously evolving during recent years. This paper will briefly present experience gained in relationship with some relevant aspects of fire risk analysis. Associated circuits need to be evaluated to determine if cable faults can prevent or cause the maloperation of redundant safety related systems. If a circuit is not properly protected by an isolation device, fire damage to a cable could propagate to other safe shutdown cables. In order to check that the coordination is adequate, existing electrical protections coordination studies have been analyzed and, for some plants, additional analyses have been performed for DC and AC for instrumentation an control (I and C) systems. Spurious actuations are also a basic part of the analysis of the consequence of a fire, which should consider any possible actuation that can prevent or affect the performance of a system or safety function. In this context, it was furthermore necessary to take into account the possibility of a combination of several spurious actuations that can result in a specific consequence, according to Appendix G of NEI 00-01 Rev. 2. These are the so-called Multiple Spurious Operations (MSOs). One key element in fire analysis is the availability of validated fire models used to estimate the spread of fire and the failure time of cable raceways. NFPA 805 states that fire models shall only be applied within the limitations of the given model. The applicability of the validation results is determined using normalized parameters traditionally used in fire modeling applications. Normalized parameters assessed in NUREG-1934 may be used to compare NPP fire scenarios with validation experiments. If some of the parameters do

  1. Ecuador: David y Goliat en el cable

    Directory of Open Access Journals (Sweden)

    Blasco Fernando Checa Montúfar

    2015-01-01

    Full Text Available Hay un enorme desequilibrio en la televisión ecuatoriana pagada, por un lado la existencia solo de dos operadores de cable, uno de los cuales capta el 90 por ciento del mercado actual y por otro, la histórica supremacía de Estados Unidos en la pantalla electrónica latinoamericana es más dramática en el cable ecuatoriano: en algún caso, el 80 por ciento de canales ofertados provienen de ese país. Es necesaria una "honda" sostenida, compartida y plural para derribar esta supremacía.

  2. Calorimetric measurements of losses in HTS cables

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Veje, Niels Erling Winsløv; Rasmussen, Carsten

    2001-01-01

    A calorimetric test rig is used to investigate various loss components in a 10 m long superconducting cable model. A calorimetric technique, based on thermocouple measurements, is used to measure the losses of the 10 m long superconducting cable model. The current dependent losses are also measured...... electrically and compared with the losses obtained with the calorimetric method. The results obtained by the two methods are consistent. Based on an I2 (current) fitting procedure, the loss, caused by the eddy current generated in the stainless steel cryostat housing, and the hysteresis loss generated...

  3. Flat conductor cable for electrical packaging

    Science.gov (United States)

    Angele, W.

    1972-01-01

    Flat conductor cable (FCC) is relatively new, highly promising means for electrical packaging and system integration. FCC offers numerous desirable traits (weight, volume and cost savings, flexibility, high reliability, predictable and repeatable electrical characteristics) which make it extremely attractive as a packaging medium. FCC, today, finds wide application in everything from integration of lunar equipment to the packaging of electronics in nuclear submarines. Described are cable construction and means of termination, applicable specifications and standards, and total FCC systems. A list of additional sources of data is also included for more intensive study.

  4. Power applications for superconducting cables in Denmark

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Østergaard, Jacob; Olsen, S. Krüger

    1999-01-01

    In Denmark a growing concern for environmental protection has lead to wishes that the open country is kept free of overhead lines as far as possible. New lines under 100 kV and existing 60/50 kV lines should be established as underground cables. Superconducting cables represent an interesting...... can be combined with other new technologies such as HVDC light transmission using isolated gate bipolar transistors (IGBTs). The network needed in a system with a substantial wind power generation has to be very strong in order to handle energy fluctuations. Such a network will be possible...

  5. Influence of Icing on Bridge Cable Aerodynamics

    DEFF Research Database (Denmark)

    Koss, Holger; Frej Henningsen, Jesper; Olsen, Idar

    2013-01-01

    °C may lead to large amplitude vibrations of bridge cables under wind action. For the prediction of aerodynamic instability quasi-steady models have been developed estimating the cable response magnitude based on structural properties and aerodynamic force coefficients for drag, lift and torsion....... The determination of these force coefficients require a proper simulation of the ice layer occurring under the specific climatic conditions, favouring real ice accretion over simplified artificial reproduction. The work presented in this paper was performed to study the influence of ice accretion on the aerodynamic...

  6. Can Charcoal Provide Information About Fire Effects and Fire Severity?

    Science.gov (United States)

    Belcher, Claire; Hudpsith, Victoria; Doerr, Stefan; Santin, Cristina

    2016-04-01

    Building an understanding of the impact of a wildfire is critical to the management of ecosystems. Aspects of fire severity such as the amount of soil heating, can relate to post-fire ecosystem recovery. Yet, there is no quantitative measure of this in current post-burn fire severity assessments, which are mostly qualitative ground-based visual assessments of organic matter loss, and as such can be subjective and variable between ecosystems. In order to develop a unifying fire severity assessment we explore the use of charcoal produced during a wildfire, as a tool. Charcoal has been suggested to retain some information about the nature of the fire in which it was created and one such physical property of charcoal that can be measured post-fire is its ability to reflect light when studied under oil using reflectance microscopy. The amount of light reflected varies between charcoals and is thought to be explained by the differential ordering of graphite-like phases within the char however, to what aspects of a fire's nature this alteration pertains is unknown. We have explored the formation of charcoal reflectance in 1) laboratory-based experiments using an iCone calorimeter and in 2) experimental forest scale and natural wildland fires occurring in Canada in spring 2015. In our laboratory experiments we assessed the formation and evolution of charcoal reflectance during pre-ignition heating, peak fire intensity through to the end of flaming and the transition to oxidative/smoldering heating regimes. In the prescribed and natural wildland fires we positioned the same woods used in our laboratory experiments, rigged with thermocouples in the path of oncoming fires in order to assess the resulting charcoal reflectance in response to the heating regime imposed by the fire on the samples. In this presentation we will outline our approach, findings and discuss the potential for charcoal reflectance to provide a tool in post-fire assessments seeking to determine levels of

  7. The Protection of Undersea Cables: A Global Security Threat

    Science.gov (United States)

    2012-03-07

    10 Samuel Morse demonstrated “ Morse Code” in 1844 and patented the design in 1850. The first undersea ( telegraph ) cable was laid between England... telegraph cable linked London with the new world, via Newfoundland.2 The 143 words transmitted in 10 hours, replaced a one-way dispatch that would...Cable History The history of undersea cables started in 1795 when a Spaniard named Salva suggested the idea of underwater telegraphic communication

  8. Smoke production in fires

    Energy Technology Data Exchange (ETDEWEB)

    Sarvaranta, L.; Kokkala, M. [VTT Building Technology, Espoo (Finland). Building Physics, Building Services and Fire Technology

    1995-12-31

    Characterization of smoke, factors influencing smoke production and experimental methods for measuring smoke production are discussed in this literature review. Recent test-based correlation models are also discussed. Despite the large number of laboratories using different fire testing methods, published smoke data have been scarce. Most technical literature on smoke production from building materials is about experimental results in small scale tests. Compilations from cone calorimeter tests have been published for a few materials, e.g. upholstered furniture materials and some building products. Mass optical density data and compilations of gravimetric soot data are available for various materials as well as a number of smoke obscuration values. For a given material often a wide range of values of smoke output can be found in the literature and care should be exercised in applying the appropriate value in each case. In laboratory experiments, the production of smoke and its optical properties are often measured simultaneously with other fire properties as heat release and flame spread. The measurements are usually dynamic in full scale, i.e. they are performed in a flow-through system. In small scale they may be either dynamic, as in the cone calorimeter, or static, i.e. the smoke is accumulated in a closed box. Small-scale tests are necessary as practical tools. Full-scale tests are generally considered to be more reliable and are needed to validitate the small-scale tests

  9. 24 CFR 3285.906 - Telephone and cable TV.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Telephone and cable TV. 3285.906... Installation Instructions § 3285.906 Telephone and cable TV. It is recommended that the installation instructions explain that telephone and cable TV wiring should be installed in accordance with requirements of...

  10. 24 CFR 3285.704 - Telephone and cable TV.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Telephone and cable TV. 3285.704....704 Telephone and cable TV. Refer to § 3285.906 for considerations pertinent to installation of telephone and cable TV. ...

  11. Results from the Danish high temperature superconducting power cable project

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Østergaard, Jacob

    2002-01-01

    For the first time, a high temperature superconducting (HTS) demonstration cable system has been installed in a utility network supplying electricity to consumers. The cable is a 30-m long, 30kVrms, 2, 000Arms cable, installed in the network of Copenhagen Energy at a substation supplying...

  12. Perturbation of near-field scan from connected cables

    DEFF Research Database (Denmark)

    Sørensen, Morten; Franek, Ondrej; Pedersen, Gert Frølund

    2012-01-01

    The perturbation of near-fields scan from connected cables are investigated and how to handle the cables is discussed. A connected cable induced small but theoretical detectable changes in the near-field. This change can be seen in Huygens’ box simulations (equivalent source currents on a box) at...

  13. Cable Television 1980: Status and Prospect for Higher Education.

    Science.gov (United States)

    Baus, F., Ed.

    Baseline information for the would-be cable television educational programer is provided by two papers, one an overview of the state of the cable television industry, and the other a report on a marketing study conducted to determine consumer attitudes toward cable TV as an educational medium. In "The Promise and Reality of Cable…

  14. North Sea submarine cable disruptions and fishing activity

    NARCIS (Netherlands)

    Hintzen, N.T.; Machiels, M.A.M.

    2014-01-01

    At the North Sea seafloor, numerous submarine cables are positioned that connect telecommunication networks between countries. Worldwide, human activities cause most of the cable disruptions with fisheries accounting for nearly half of all reported faults. Due to a recent increase of submarine cable

  15. Numerical solutions of the current distribution in superconducting cables

    NARCIS (Netherlands)

    Hartmann, R.A.; Rem, P.C.; van de Klundert, L.J.M.

    1987-01-01

    Superconducting cables are described by current sheets using the continuum model of W. Carr Jr. [1] and assuming an anisotropic conductivity. Two different situations are considered: a) finite length of cable in spatially independent magnetic field; b) infinitely long cable in a periodical magnetic

  16. FCC Commissioner, Legal Assistant and Staff Perceptions of Cable TV.

    Science.gov (United States)

    Krugman, Dean M.

    1979-01-01

    Describes a methodology used in interviewing Federal Communications Commission commissioners, legal assistants, and Cable Bureau staff members about their attitudes toward the cable industry and regulation; reports results of the interviews, noting respondents' disappointment in the lack of cable growth. (GT)

  17. Understanding losses in three core armoured submarine cables

    DEFF Research Database (Denmark)

    Silva, Filipe Miguel Faria da; Ebdrup, Thomas; Bak, Claus Leth

    2016-01-01

    As the number of offshore wind farms increases so does the number of array cables. The array cables are used to interconnect the wind turbines in a wind farm and to connect the wind farm to a collector platform, whereas the connection to shore is performed by means of a HV transmission cable. For...

  18. 47 CFR 76.111 - Cable sports blackout.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Cable sports blackout. 76.111 Section 76.111... CABLE TELEVISION SERVICE Network Non-duplication Protection, Syndicated Exclusivity and Sports Blackout § 76.111 Cable sports blackout. (a) No community unit located in whole or in part within the specified...

  19. 30 CFR 75.804 - Underground high-voltage cables.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Underground high-voltage cables. 75.804 Section... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution § 75.804 Underground high-voltage cables. (a) Underground high-voltage cables used in resistance...

  20. 46 CFR 111.60-6 - Fiber optic cable.

    Science.gov (United States)

    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...

  1. 30 CFR 75.600-1 - Approved cables; flame resistance.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Approved cables; flame resistance. 75.600-1 Section 75.600-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE... cables; flame resistance. Cables shall be accepted or approved by MSHA as flame resistant. ...

  2. 30 CFR 75.600 - Trailing cables; flame resistance.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Trailing cables; flame resistance. 75.600 Section 75.600 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE... cables; flame resistance. Trailing cables used in coal mines shall meet the requirements established by...

  3. Decreasing Fires in Mediterranean Europe.

    Directory of Open Access Journals (Sweden)

    Marco Turco

    Full Text Available Forest fires are a serious environmental hazard in southern Europe. Quantitative assessment of recent trends in fire statistics is important for assessing the possible shifts induced by climate and other environmental/socioeconomic changes in this area. Here we analyse recent fire trends in Portugal, Spain, southern France, Italy and Greece, building on a homogenized fire database integrating official fire statistics provided by several national/EU agencies. During the period 1985-2011, the total annual burned area (BA displayed a general decreasing trend, with the exception of Portugal, where a heterogeneous signal was found. Considering all countries globally, we found that BA decreased by about 3020 km2 over the 27-year-long study period (i.e. about -66% of the mean historical value. These results are consistent with those obtained on longer time scales when data were available, also yielding predominantly negative trends in Spain and France (1974-2011 and a mixed trend in Portugal (1980-2011. Similar overall results were found for the annual number of fires (NF, which globally decreased by about 12600 in the study period (about -59%, except for Spain where, excluding the provinces along the Mediterranean coast, an upward trend was found for the longer period. We argue that the negative trends can be explained, at least in part, by an increased effort in fire management and prevention after the big fires of the 1980's, while positive trends may be related to recent socioeconomic transformations leading to more hazardous landscape configurations, as well as to the observed warming of recent decades. We stress the importance of fire data homogenization prior to analysis, in order to alleviate spurious effects associated with non-stationarities in the data due to temporal variations in fire detection efforts.

  4. Fire Synthesis

    Indian Academy of Sciences (India)

    Fire Synthesis - Preparation of Alumina Products. Tanu Mimani. Volume 16 Issue 12 December 2011 pp 1324-1332. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/016/12/1324-1332. Keywords. Alumina; combustion; refractory materials; urea. Author Affiliations. Tanu Mimani1.

  5. Fire Synthesis

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 5; Issue 2. Fire Synthesis - Preparation of Alumina Products. Tanu Mimani. General Article Volume 5 Issue 2 February 2000 pp 50-57. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/005/02/0050-0057 ...

  6. Forest Fires

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 11. Forest Fires - Origins and Ecological Paradoxes. K Narendran. General Article Volume 6 Issue 11 November 2001 pp 34-41. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/006/11/0034-0041 ...

  7. Broadband Wireline Provider Service: Cable Modem - Other; BBRI_cableOther12

    Data.gov (United States)

    University of Rhode Island Geospatial Extension Program — This dataset represents the availability of wireline broadband Internet access in Rhode Island via "Cable Modem - Other" technology. Broadband availability is...

  8. Broadband Wireline Provider Service: Cable Modem - DOCSIS 3.0; BBRI_cableDOCSIS12

    Data.gov (United States)

    University of Rhode Island Geospatial Extension Program — This dataset represents the availability of wireline broadband Internet access in Rhode Island via "Cable Modem - DOCSIS 3.0" technology. Broadband availability is...

  9. Fire and forest history at Mount Rushmore.

    Science.gov (United States)

    Brown, Peter M; Wienk, Cody L; Symstad, Amy J

    2008-12-01

    Mount Rushmore National Memorial in the Black Hills of South Dakota is known worldwide for its massive sculpture of four of the United States' most respected presidents. The Memorial landscape also is covered by extensive ponderosa pine (Pinus ponderosa) forest that has not burned in over a century. We compiled dendroecological and forest structural data from 29 plots across the 517-ha Memorial and used fire behavior modeling to reconstruct the historical fire regime and forest structure and compare them to current conditions. The historical fire regime is best characterized as one of low-severity surface fires with occasional (> 100 years) patches (fire. We estimate that only approximately 3.3% of the landscape burned as crown fire during 22 landscape fire years (recorded at > or = 25% of plots) between 1529 and 1893. The last landscape fire was in 1893. Mean fire intervals before 1893 varied depending on spatial scale, from 34 years based on scar-to-scar intervals on individual trees to 16 years between landscape fire years. Modal fire intervals were 11-15 years and did not vary with scale. Fire rotation (the time to burn an area the size of the study area) was estimated to be 30 years for surface fire and 800+ years for crown fire. The current forest is denser and contains more small trees, fewer large trees, lower canopy base heights, and greater canopy bulk density than a reconstructed historical (1870) forest. Fire behavior modeling using the NEXUS program suggests that surface fires would have dominated fire behavior in the 1870 forest during both moderate and severe weather conditions, while crown fire would dominate in the current forest especially under severe weather. Changes in the fire regime and forest structure at Mount Rushmore parallel those seen in ponderosa pine forests from the southwestern United States. Shifts from historical to current forest structure and the increased likelihood of crown fire justify the need for forest restoration before a

  10. Bulk Electrical Cable Non-Destructive Examination Methods for Nuclear Power Plant Cable Aging Management Programs

    Energy Technology Data Exchange (ETDEWEB)

    Glass, Samuel W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jones, Anthony M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fifield, Leonard S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hartman, Trenton S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-09-01

    This Pacific Northwest National Laboratory milestone report describes progress to date on the investigation of nondestructive test methods focusing particularly on bulk electrical test methods 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 nuclear power plants consider applying for second, or subsequent, license renewal to extend their operating period from 60 years to 80 years, it is important to understand how the materials installed in plant systems and components will age during that time and develop aging management programs to assure continued 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, however, is directed toward the more demanding challenge of assuring the cable function under accident or DBE. 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, however, is a destructive test so the test programs must apply an array of other nondestructive examination (NDE) tests to assure or infer the overall set of cable’s system integrity. Assessment of cable integrity is further complicated in many cases by vendor’s use of dissimilar material for jacket and insulation. Frequently the jacket will degrade more rapidly than the underlying insulation. Although this can serve as an early alert to cable damage, direct test of the cable insulation without violating the protective jacket becomes problematic. This report addresses the range of bulk electrical NDE cable tests that are or could be practically implemented in a field-test situation with a particular focus on frequency domain reflectometry (FDR). The FDR test method offers numerous advantages

  11. Controls on fire activity over the Holocene

    Science.gov (United States)

    Kloster, S.; Brucher, T.; Brovkin, V.; Wilkenskjeld, S.

    2015-05-01

    Changes in fire activity over the last 8000 years are simulated with a global fire model driven by changes in climate and vegetation cover. The changes were separated into those caused through variations in fuel availability, fuel moisture or wind speed, which react differently to changes in climate. Disentangling these controlling factors helps in understanding the overall climate control on fire activity over the Holocene. Globally the burned area is simulated to increase by 2.5% between 8000 and 200 cal yr BP, with larger regional changes compensating nearly evening out on a global scale. Despite the absence of anthropogenic fire ignitions, the simulated trends in fire activity agree reasonably well with continental-scale reconstructions from charcoal records, with the exception of Europe. For some regions the change in fire activity is predominantly controlled through changes in fuel availability (Australia monsoon, Central America tropics/subtropics). For other regions changes in fuel moisture are more important for the overall trend in fire activity (North America, Sub-Saharan Africa, Europe, Asia monsoon). In Sub-Saharan Africa, for example, changes in fuel moisture alone lead to an increase in fire activity between 8000 and 200 cal yr BP, while changes in fuel availability lead to a decrease. Overall, the fuel moisture control is dominating the simulated fire activity for Sub-Saharan Africa. The simulations clearly demonstrate that both changes in fuel availability and changes in fuel moisture are important drivers for the fire activity over the Holocene. Fuel availability and fuel moisture do, however, have different climate controls. As such, observed changes in fire activity cannot be related to single climate parameters such as precipitation or temperature alone. Fire models, as applied in this study, in combination with observational records can help in understanding the climate control on fire activity, which is essential to project future fire

  12. Microminiature coaxial cable and method of manufacture

    Science.gov (United States)

    Bongianni, Wayne L.

    1989-01-01

    A coaxial cable is provided having a ribbon inner conductor surrounded by a dielectric and a circumferential conductor. The coaxial cable may be microminiature comprising a very thin ribbon strip conductor from between 5 to 15 .mu.m thick and from 150 to 200 .mu.m wide, having a surrounding foamed dielectric or parylene applied thereon by a vapor plasma process and an outer conductor of an adhering high conductivity metal vacuum deposited on the dielectric. Alternately, the foam dielectric embodiment may have a contiguous parylene coating applied adjacent the inner conductor or the outer conductor or both. Also, the cable may be fabricated by forming a thin ribbon of strip conductive material into an inner conductor, applying thereabout a dielectric by spraying on a solution of polystyrene and polyethylene and then vacuum depositing and adhering high conductivity metal about the dielectric. The cable strength may be increased by adding glass microfilament fibers or glass microspheres to the solution of polystyrene and polyethylene. Further, the outer conductive layer may be applied by electroless deposition in an aqueous solution rather than by vacuum deposition. A thin coating of parylene is preferably applied to the outer conductor to prevent its oxidation and inhibit mechanical abrasion.

  13. Microminiature coaxial cable and methods of manufacture

    Science.gov (United States)

    Bongianni, W.L.

    1983-12-29

    A coaxial cable is provided having a ribbon inner conductor surrounded by a dielectric and a circumferential conductor. The coaxial cable may be microminiature comprising a very thin ribbon strip conductor from between 5 to 15 ..mu..m thick and from 150 to 200 ..mu..m wide, having a surrounding foamed dielectric or parylene applied thereon by a vapor plasma process and an outer conductor of an adhering high conductivity metal vacuum deposited on the dieleectric. Alternately the foam dielectric embodiment may have a contiguous parylene coating applied adjacent the inner conductor or the outer conductor or both. Also, the cable may be fabricated by forming a thin ribbon of strip conductive material into an inner conductor, applying thereabout a dielectric by spraying on a solution of polystyrene and polyethylene and then vacuum depositing and adhering high conductivity metal about the dielectric. The cable strength may be increased by adding glass microfilament fibers or glass microballoons to the solution of polystyrene and polyethylene. Further, the outer conductive layer may be applied by electroless deposition in an aqueous solution rather than by vacuum deposition. A thin coating of parylene is preferably applied to the outer conductor to prevent its oxidation and inhibit mechanical abrasion.

  14. Microminiature coaxial cable and methods manufacture

    Science.gov (United States)

    Bongianni, Wayne L.

    1986-01-01

    A coaxial cable is provided having a ribbon inner conductor surrounded by a dielectric and a circumferential conductor. The coaxial cable may be microminiature comprising a very thin ribbon strip conductor from between 5 to 15 .mu.m thick and from 150 to 200 .mu.m wide, having a surrounding foamed dielectric or parylene applied thereon by a vapor plasma process and an outer conductor of an adhering high conductivity metal vacuum deposited on the dielectric. Alternately the foam dielectric embodiment may have a contiguous parylene coating applied adjacent the inner conductor or the outer conductor or both. Also, the cable may be fabricated by forming a thin ribbon of strip conductive material into an inner conductor, applying thereabout a dielectric by spraying on a solution of polystyrene and polyethylene and then vacuum depositing and adhering high conductivity metal about the dielectric. The cable strength may be increased by adding glass microfilament fibers or glass microballoons to the solution of polystyrene and polyethylene. Further, the outer conductive layer may be applied by electroless deposition in an aqueous solution rather than by vacuum deposition. A thin coating of parylene is preferably applied to the outer conductor to prevent its oxidation and inhibit mechanical abrasion.

  15. Microminiature coaxial cable and method of manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Bongianni, W.L.

    1989-03-28

    A coaxial cable is provided having a ribbon inner conductor surrounded by a dielectric and a circumferential conductor. The coaxial cable may be microminiature comprising a very thin ribbon strip conductor from between 5 to 15 [mu]m thick and from 150 to 200 [mu]m wide, having a surrounding foamed dielectric or parylene applied thereon by a vapor plasma process and an outer conductor of an adhering high conductivity metal vacuum deposited on the dielectric. Alternately, the foam dielectric embodiment may have a contiguous parylene coating applied adjacent the inner conductor or the outer conductor or both. Also, the cable may be fabricated by forming a thin ribbon of strip conductive material into an inner conductor, applying thereabout a dielectric by spraying on a solution of polystyrene and polyethylene and then vacuum depositing and adhering high conductivity metal about the dielectric. The cable strength may be increased by adding glass microfilament fibers or glass microspheres to the solution of polystyrene and polyethylene. Further, the outer conductive layer may be applied by electroless deposition in an aqueous solution rather than by vacuum deposition. A thin coating of parylene is preferably applied to the outer conductor to prevent its oxidation and inhibit mechanical abrasion. 2 figs.

  16. Microminiature coaxial cable and methods manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Bongianni, W.L.

    1986-04-08

    A coaxial cable is provided having a ribbon inner conductor surrounded by a dielectric and a circumferential conductor. The coaxial cable may be microminiature comprising a very thin ribbon strip conductor from between 5 to 15 [mu]m thick and from 150 to 200 [mu]m wide, having a surrounding foamed dielectric or parylene applied thereon by a vapor plasma process and an outer conductor of an adhering high conductivity metal vacuum deposited on the dielectric. Alternately the foam dielectric embodiment may have a contiguous parylene coating applied adjacent the inner conductor or the outer conductor or both. Also, the cable may be fabricated by forming a thin ribbon of strip conductive material into an inner conductor, applying thereabout a dielectric by spraying on a solution of polystyrene and polyethylene and then vacuum depositing and adhering high conductivity metal about the dielectric. The cable strength may be increased by adding glass microfilament fibers or glass microballoons to the solution of polystyrene and polyethylene. Further, the outer conductive layer may be applied by electroless deposition in an aqueous solution rather than by vacuum deposition. A thin coating of parylene is preferably applied to the outer conductor to prevent its oxidation and inhibit mechanical abrasion. 2 figs.

  17. 14 CFR 25.689 - Cable systems.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Cable systems. 25.689 Section 25.689 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... smaller than 1/8 inch in diameter may be used in the aileron, elevator, or rudder systems; and (2) Each...

  18. History of cable-stayed bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

    The principle of supporting a bridge deck by inclined tension members leading to towers on either side of the span has been known for centuries. However, the real development of cable-stayed bridges did not begin before the 1950s. Since then the free span has been increased from 183 m in the Strö...

  19. Space charge fields in DC cables

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson; Crichton, George C; Pedersen, Aage

    1996-01-01

    The space charge that accumulates in DC cables can, mathematically, be resolved into two components. One is related to the temperature and the other to the magnitude of the electric field strength. Analytical expressions for the electric fields arising from each of these space charge components...

  20. Submarine Telecommunication Cables in Disputed Maritime Areas

    NARCIS (Netherlands)

    van Logchem, Youri

    2014-01-01

    There are a considerable number of maritime areas where no boundary exists, or where a boundary is delimited only in part. This article deals with the issue of submarine telecommunication cables, which are sometimes placed on the seabed or buried in the subsoil of areas that are claimed by multiple

  1. Cinema Futures: Cain, Abel or Cable?

    NARCIS (Netherlands)

    Elsaesser, Thomas; Hoffmann, Kay

    1998-01-01

    In the late 1960s, the cinema was pronounced dead. Television, like a Biblical Cain had slain his brother Abel. Some thirty years later, a remarkable reversal: rarely has the cinema been more popular. And yet, rarely has the cinema's future seemed more uncertain. Cinema Futures: Cain, Abel or Cable?

  2. Power laws from linear neuronal cable theory

    DEFF Research Database (Denmark)

    Pettersen, Klas H; Lindén, Henrik Anders; Tetzlaff, Tom

    2014-01-01

    suggested to be at the root of this phenomenon, we here demonstrate a possible origin of such power laws in the biophysical properties of single neurons described by the standard cable equation. Taking advantage of the analytical tractability of the so called ball and stick neuron model, we derive general...

  3. Study on Impedance Characteristics of Aircraft Cables

    Directory of Open Access Journals (Sweden)

    Weilin Li

    2016-01-01

    Full Text Available Voltage decrease and power loss in distribution lines of aircraft electric power system are harmful to the normal operation of electrical equipment and may even threaten the safety of aircraft. This study investigates how the gap distance (the distance between aircraft cables and aircraft skin and voltage frequency (variable frequency power supply will be adopted for next generation aircraft will affect the impedance of aircraft cables. To be more precise, the forming mechanism of cable resistance and inductance is illustrated in detail and their changing trends with frequency and gap distance are analyzed with the help of electromagnetic theoretical analysis. An aircraft cable simulation model is built with Maxwell 2D and the simulation results are consistent with the conclusions drawn from the theoretical analysis. The changing trends of the four core parameters of interest are analyzed: resistance, inductance, reactance, and impedance. The research results can be used as reference for the applications in Variable Speed Variable Frequency (VSVF aircraft electric power system.

  4. Galloping instability to chaos of cables

    CERN Document Server

    Luo, Albert C J

    2017-01-01

    This book provides students and researchers with a systematic solution for fluid-induced structural vibrations, galloping instability and the chaos of cables. They will also gain a better understanding of stable and unstable periodic motions and chaos in fluid-induced structural vibrations. Further, the results presented here will help engineers effectively design and analyze fluid-induced vibrations.

  5. Observation of polyphosphate granules in cable bacteria

    Science.gov (United States)

    Yang, T.; Nielsen, L. P.; Risgaard-Petersen, N.

    2015-12-01

    Cable bacteria are long filamentous bacteria that capable for long distance electron transport: transporting electrons derived from oxidizing sulfide in anoxic layers, to oxygen at the sediment surface, over a distance of centimeters. Cable bacteria are found in many types of freshwater and marine sediment all over the world, with density of approximately thousands of kilometers per square meter. These long filaments are composed by individual cells closely related to Desulfobulbaceae, connected with a shared outer membrane inside which the strings structure are presumed to be highly conductive. The observed doubling time of cells within the filament is about 20 min, which is among the shortest compare to other bacteria. In these cable cells, we constantly observed polyphosphate granules (poly-P), regardless of cell dimension and shape. This is very interesting since it has long been recognized that the microbial polyP content is low during rapid growth and increases under unfavorable conditions, for example, increasing sulfide concentration and anoxia resulted in a decomposition of poly-P in Beggiatoa. Here, we investigated marine cable bacteria from Netherland and Aarhus Bay, focusing on the poly-P dynamics under various redox conditions. In poly-P stained cells, typically there are two big poly-P granules locate at each polar. In dividing cells, however, the morphology of poly-P changed to six small granules precisely arranged to two row. Moreover, the cells seem be able to continuously divide more than one time without elongation step. These varied poly-P morphologies demonstrate that poly-P is closely related to the cell growth and cell division, by an unknown mechanism. Individual cable filaments were picked up and were exposed to different redox conditions; our primary data indicated the cable cells could suffer anoxic condition better than oxic condition. We also detected decomposition of poly-P under anoxia. These results call for an in-depth examination

  6. Review of methods for modelling forest fire risk and hazard | Yakubu ...

    African Journals Online (AJOL)

    Forest fires (wildfires) have become a major concern for several environmental experts. Assessment of fire effects at local scale is increasingly considered a critical aspect of ecosystem functioning, since fire plays a crucial role in vegetation composition, biodiversity, soil erosion and the hydrological cycle. At global scale, fire ...

  7. The Role of Cable Bacteria on Porewater Acidity in an Organic Rich Coastal Sediment

    Science.gov (United States)

    Malkin, S.; Rao, A. M. F.; Seitaj, D.; Burdorf, L. D.; Hidalgo-Martinez, S.; Tramper, A.; Meysman, F. J. R.

    2016-02-01

    Sulphide generating coastal sediments are characterised by steep redox gradients. To connect energetically favorable electron donors and acceptors in such sediments, a variety of different microbial strategies have evolved. For example, the well-known sulphur oxidizing bacteria Beggiatoa can acquire nitrate near the sediment surface and transport this electron acceptor deeper in the sediment to oxidize sulphide. Recently, a very different bacterial sulphur oxidizing lifestyle was described in marine sediments. Cable bacteria (family Desulfobulbaceae) grow as long filaments capable of conducting electrons across centimeter-scale distances, from deep reducing sediments up to surface oxic sediments. Ex situ sediment incubation experiments have shown that cable bacteria can exert a powerful control on porewater pH and associated sediment geochemistry. Yet, the biogeography of these novel bacteria, and their influence on sediment geochemistry in natural environments, is not yet well understood. Here we report on a study carried out at an intertidal mussel bed and an oyster reef in the Wadden Sea (The Netherlands). In all sediments examined, nitrate-storing Beggiatoa were nearly absent, while cable bacteria were consistently abundant, with densities reaching up to 1038 m cm-2. Microsensor profiling revealed acidity distributions that were expected for sediments hosting cable bacteria, with pH maxima near the sediment surface (up to 8.3), and pH minima near the sulphide horizon (down to 6.1). Porewater analyses revealed strongly elevated concentrations of dissolved calcium (< 35 mM), manganese (up to 250 µM), and iron (up to 700 µM), consistent with acidity-driven dissolution of calcium carbonates and iron sulphides associated with cable bacteria activity. Overall, cable bacteria are shown to exert a powerful control on the sediment acidity of coastal bivalve bed sediments, which may have broad implications, particularly for sediment alkalinity fluxes and for carbonate

  8. CFD Investigation Of The Effect Of Tilt Angles To Flow And Combustion In A 120 Mw Gas-Fired Full Scale Industrial Boiler

    Directory of Open Access Journals (Sweden)

    Wisam Saad Azeez

    2015-08-01

    Full Text Available Abstract Extensive Computational Fluid Dynamic simulations on combustion process in a 120 MW natural gas-fired industrial boiler have been performed. The boiler is of tangential system by which natural gas and air are fired into the furnace from its four corners at three different elevation levels. Fuel burners and air nozzles can be tilted in the range of 30.The simulation results show good prediction of temperature profile and distribution as compared to practical observation. The flow in the furnace is highly swirling with intense mixing of natural gas and air. The turbulence level is extremely high and combustion gas flows in helical shape in anti-clockwise direction towards the furnace exit. The results revealed the importance of the effect of heat transfer to the water wall as the temperature distribution and flow pattern is significantly difference with heat transfer and without heat transfer cases. Temperature distribution prior to the entry to the re-heater elevation is non-uniform with lower velocity at vortex core where the fireball is located. The average temperature at re-heater level reduces when the burner is negatively tilted up to -10. A slight change in firing angle will interrupt the temperature and flow contour at furnace-re-heater. However this is only true for air nozzles where the overall flow pattern inside the furnace is dominated by these sources..

  9. Proposal for using commercial submarine telecommunications cables for monitoring earthquakes and tsunamis - the SMART cable concept

    Science.gov (United States)

    Tilmann, Frederik; Howe, Bruce; Butler, Rhett; Strollo, Angelo; Weinstein, Stuart

    2017-04-01

    Hundreds of thousands of kilometres of commercial telecommunications cables traverse the world's oceans, many of them crossing large ocean basins, which are otherwise poorly sampled by geophysical sensors (seismometers or pressure gauges), or running along active continental margins, where additional observations would be particularly valuable for allowing observation of subduction zone earthquakes and offshore plate deformation from the updip end. However, as of today these cables are unaware of their environment. These cables are equipped with repeaters spaced at 50 km intervals to boost the telecom signal, though. These repeaters in principle offer access to power and bandwidth, providing the opportunity to add sensor capability to future "SMART" cables (Science Monitoring and Reliable Telecommunications). In a workshop held in early November 2016 at the German Research Centre for Geosciences in Potsdam (GFZ) research scientists, practitioners from earthquake observatories and tsunami warning centers, and engineers discussed possible applications of such SMART cables both from the viewpoint of fundamental research, i.e. Earth imaging and the study of earthquake processes and possibly plate deformation, as well as technical aspects of possible implementations by drawing on the expertise of operators of existing cabled networks. In this presentation, we will summarise the outcomes of this workshop.

  10. Longitudinal Seismic Behavior of a Single-Tower Cable-Stayed Bridge Subjected to Near-Field Earthquakes

    Directory of Open Access Journals (Sweden)

    J. Yi

    2017-01-01

    Full Text Available Cable-stayed bridges are quite sensitive to large amplitude oscillations from earthquakes and seismic damage was observed for Shipshaw Bridge and Chi-Lu Bridge during past earthquakes. In order to investigate seismic damage of cable-stayed bridges, a 1 : 20 scale model of a single-tower cable-stayed bridge with A-shaped tower was designed, constructed, and tested on shake tables at Tongji University, China. One typical near-field ground motion was used to excite the model from low to high intensity. Test result showed that severe structural damage occurred at the tower of the model including parallel concrete cracks from bottom to nearly half height of the tower, concrete spalling, and exposed bars at top tower 0.2 m above the section where two skewed legs intersect. Posttest analysis was conducted and compared with test results. It is revealed that the numerical model was able to simulate the seismic damage of the test model by modeling nonlinearity of different components for cable-stayed bridges, namely, the tower, bents, superstructure, cables, and bearings. Numerical analysis also revealed that cable relaxation, which was detected during the test, had limited influence on the overall seismic response of the bridge with maximum error of 12%.

  11. Multi-modal vibration amplitudes of taut inclined cables due to direct and/or parametric excitation

    Science.gov (United States)

    Macdonald, J. H. G.

    2016-02-01

    Cables are often prone to potentially damaging large amplitude vibrations. The dynamic excitation may be from external loading or motion of the cable ends, the latter including direct excitation, normally from components of end motion transverse to the cable, and parametric excitation induced by axial components of end motion causing dynamic tension variations. Geometric nonlinearity can be important, causing stiffening behaviour and nonlinear modal coupling. Previous analyses of the vibrations, often neglecting sag, have generally dealt with direct and parametric excitation separately or have reverted to numerical solutions of the responses. Here a nonlinear cable model is adopted, applicable to taut cables such as on cable-stayed bridges, that allows for cable inclination, small sag (such that the vibration modes are similar to those of a taut string), multiple modes in both planes and end motion and/or external forcing close to any natural frequency. Based on the method of scaling and averaging it is found that, for sinusoidal inputs and positive damping, non-zero steady state responses can only occur in the modes in each plane with natural frequencies close to the excitation frequency and those with natural frequencies close to half this frequency. Analytical solutions, in the form of non-dimensional polynomial equations, are derived for the steady state vibration amplitudes in up to three modes simultaneously: the directly excited mode, the corresponding nonlinearly coupled mode in the orthogonal plane and a parametrically excited mode with half the natural frequency. The stability of the solutions is also identified. The outputs of the equations are consistent with previous results, where available. Example results from the analytical solutions are presented for a typical inclined bridge cable subject to vertical excitation of the lower end, and they are validated by numerical integration of the equations of motion and against some previous experimental

  12. Fire Behavior (FB)

    Science.gov (United States)

    Robert E. Keane

    2006-01-01

    The Fire Behavior (FB) method is used to describe the behavior of the fire and the ambient weather and fuel conditions that influence the fire behavior. Fire behavior methods are not plot based and are collected by fire event and time-date. In general, the fire behavior data are used to interpret the fire effects documented in the plot-level sampling. Unlike the other...

  13. Converting Existing Copper Wire Firing System to a Fiber Optically Controlled Firing System for Electromagnetic Pulsed Power Experiments

    Science.gov (United States)

    2017-12-19

    Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law , no person shall be subject to any penalty for...TERMS gun fire system, fiber-optic, electromagnetic, low cost, rebuild 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT...6 (Left) Expendable cable and relay-to- gun solenoid box located in the experimental chamber room. (Right) Relay-to- gun solenoid box mounted on the

  14. Simulation of power cable ohm heat by using labview

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Y. H.; Kim, J. S.; Jung, I. S. [Korea Electric Power Research Institue, Taejon (Korea, Republic of)

    2003-07-01

    Even it is necessary to consider the ohm heat of cable conductor for the evaluation of cable aging, temperature measurement of cable conductor for the evaluation of cable aging, temperature measurement of cable conductor is impractical due to untouchable condition of cable conductor which is surrounded by insulation and jacket. We have studied the way how to get the ohm heat of conductor by measuring the surface temperature of cable jacket. We verified that jacket temperature can be controlled under the 10% error limit by applying the PI control in LabView program. The relation between surface temperature of jacket and ohm heat of conductor can be predicted after this type of experiment. This study show that the ohm heat can be delivered from temperature monitoring of jacket surface.

  15. submitter On Roebel Cable Geometry for Accelerator Magnet

    CERN Document Server

    Fleiter, J; Ballarino, A

    2016-01-01

    Roebel-type cables made of a ReBCO conductor are potential candidates for high-field accelerator magnets. The necessity to promote a large effective transverse section in a Roebel cable to avoid local overstress leading to degradation in electrical performance has been recently addressed. In this paper, a new geometry of meander tapes for a Roebel cable that enhances both the transverse effective section and the current margin at crossing segments is discussed. As Roebel cables are bent at the coil ends, the modulation of the bending radius of strands along the cable pitch leads to a shift of the strands with respect to each other. The shift magnitude is analytically investigated in this paper as a function of both cable features and coil geometry. Finally, the minimum transposition pitch of Roebel cables is determined on the basis of coil characteristics.

  16. Fire Symfonier

    DEFF Research Database (Denmark)

    Nielsen, Svend Hvidtfelt

    2009-01-01

    sidste fire symfonier. Den er måske snarere at opfatte som et præludium til disse. At påstå, at symfonierne fra Holmboes side er planlagt til at være beslægtede, ville være at gå for vidt. Alene de 26 år, der skiller den 10. fra den 13., gør påstanden - i bedste fald - dubiøs. Når deres udformning...... udkrystallisering som i de sidste små 30 år af hans virke har afkastet disse fire variationer over en grundlæggende central holmboesk fornemmelse for form, melodi, klang og rytme. Denne oplevelse har fået mig til at udforske symfonierne, for at finde til bunds i dette holmboeske fællestræk, som jeg mener her står...

  17. Literature study regarding fire protection in nuclear power plants. Part I: Fire rated separations; Litteraturstudie angaaende brandskydd i kaernkraftverk. Del I: Brandteknisk separation

    Energy Technology Data Exchange (ETDEWEB)

    Isaksson, S. [Swedish Testing and Research Inst., Boraas (Sweden)

    1995-06-01

    This literature study has been made on behalf of the Swedish Nuclear Power Inspectorate. The aim is to describe different aspects of fire protection in nuclear power plants. Conventional building codes can not give guidance on where to make fire rated separations in order to separate redundant trains of safety systems. The separation must originate in functional demands from the authorities on what functions are essential during and after a fire, and under what circumstances these functions shall be retained, i.e. the number of independent faults and initiating events. As a basic demand it is suggested to rate the strength of separations according to conventional building code, based on fire load. The whole separating construction shall have the same fire rating, including the ventilation system. Deviations from the basic demand can de done in case it can be proven that it is possible to compensate some or all of the fire rating with other measures. There is a general lack of statistical information regarding the reliability of fire separating constructions such as walls, fire doors, penetration seals and fire dampers. The amount of cables penetrating a seal is in many cases much higher in real installations than what has been tested for type approval. It would therefore be valuable to perform a furnace test with a more representative amount of cables passing through a penetration seal. Tests have shown that the 20 foot horizontal separation distance stipulated by NRC is not a guarantee against fire damage. Spatial separations based on general requirements shall not be allowed, but considered from case to case based on actual circumstances. For fire protection by isolation or coatings, it is of great importance to choose the method of protection carefully, to be compatible with the material it shall be applied on, and the environment and types of fire that may occur. 48 refs, 2 figs, 5 tabs.

  18. Development of an underwater ROV system for submarine cable maintenance. Kaitei cable maintenance yo suichu robot no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Iyama, T.; Takahashi, Y.; Kaya, F.; Shigemitsu, T. (Ishikawajima-Harima Heavy Industries, Co. Ltd., Tokyo (Japan))

    1992-07-01

    For the purpose of repairing, burying, and inspecting submarine telecommunication cables more speedily and at greater depth than conventional processes, an underwater remotely operated robot system for submarine cable maintenance has been developed. The system is composed of an underwater remotely operated vehicle (ROV), tether cables, a tether management system, umbilical cables, a launch and recovery system, control units, and electric power units. The ROV is loaded with thrusters for propulsion, a television camera, a cable location system, manipulators, a cable gripper/cutter unit, a cable burier/digger unit, a variable ballast unit, various sensors, et al. Since its entrance into service in October, 1989, the system has been successfully operated in various sea areas around Japan with a crew of three or four for operation and maintenance. This paper describes the outline of the system configuration and their specifications. 12 figs., 1 tab.

  19. Understanding Long-term, Large-scale Shoreline Change and the Sediment Budget on Fire Island, NY, using a 3D hydrodynamics-based model

    Science.gov (United States)

    List, J. H.; Safak, I.; Warner, J. C.; Schwab, W. C.; Hapke, C. J.; Lentz, E. E.

    2016-02-01

    The processes responsible for long-term (decadal) shoreline change and the related imbalance in the sediment budget on Fire Island, a 50 km long barrier island on the south coast of Long Island, NY, has been the subject of debate. The estimated net rate of sediment leaving the barrier at the west end of the island is approximately double the estimated net rate of sediment entering in the east, but the island-wide average sediment volume change associated with shoreline change is near zero and cannot account for this deficit. A long-held hypothesis is that onshore sediment flux from the inner continental shelf within the western half of the island is responsible for balancing the sediment budget. To investigate this possibility, we use a nested, 3-D, hydrodynamics-based modeling system (COAWST) to simulate the island-wide alongshore and cross-shore transport, in combination with shoreline change observations. The modeled, net alongshore transport gradients in the nearshore predict that the central part of Fire Island should be erosional, yet shoreline change observations show this area to be accretionary. We compare the model-predicted alongshore transport gradients with the flux gradients that would be required to generate the observed shoreline change, to give the pattern of sediment volume gains or losses that cannot be explained by the modeled alongshore transport gradients. Results show that the western 30 km of coast requires an input of sediment, supporting the hypothesis of onshore flux in this area. The modeled cross-shore flux of sediment between the shoreface and inner shelf is consistent these results, with onshore-directed bottom currents creating an environment more conducive to onshore sediment flux in the western 30 km of the island compared to the eastern 20 km. We conclude that the cross-shore flux of sediment can explain the shoreline change observations, and is an integral component of Fire Island's sediment budget.

  20. Fire Safety Training Handbook.

    Science.gov (United States)

    Montgomery County Dept. of Fire and Rescue Services, Rockville, MD. Div. of Fire Prevention.

    Designed for a community fire education effort, particularly in which local volunteers present general information on fire safety to their fellow citizens, this workbook contains nine lessons. Included are an overview of the household fire problem; instruction in basic chemistry and physics of fire, flammable liquids, portable fire extinguishers,…

  1. Determination of aerodynamic damping and force coefficients of filleted twin cables in dry conditions through passive-dynamic wind tunnel tests

    DEFF Research Database (Denmark)

    Mattiello, E.; Eriksen, M. B.; Georgakis, Christos T.

    Moderate amplitude vibrations continue to be reported on the Øresund Bridge cables, although fitted with fillets and dampers. To further investigate the aerodynamics of the bridge’s twin-cable arrangement, 1:2.3 scale passive-dynamic wind tunnel tests of the cables were performed at the DTU....../FORCE Technology Climatic Wind Tunnel facility. The measured aerodynamic damping of the twin-cable arrangement in dry conditions was compared to the values obtained from full-scale monitoring and from an analytical model using static force coefficients. The comparison revealed broad agreement in the investigated...... Re range, as did the force coefficients obtained from dynamic and static tests....

  2. Automated wireless monitoring system for cable tension using smart sensors

    Science.gov (United States)

    Sim, Sung-Han; Li, Jian; Jo, Hongki; Park, Jongwoong; Cho, Soojin; Spencer, Billie F.; Yun, Chung-Bang

    2013-04-01

    Cables are critical load carrying members of cable-stayed bridges; monitoring tension forces of the cables provides valuable information for SHM of the cable-stayed bridges. Monitoring systems for the cable tension can be efficiently realized using wireless smart sensors in conjunction with vibration-based cable tension estimation approaches. This study develops an automated cable tension monitoring system using MEMSIC's Imote2 smart sensors. An embedded data processing strategy is implemented on the Imote2-based wireless sensor network to calculate cable tensions using a vibration-based method, significantly reducing the wireless data transmission and associated power consumption. The autonomous operation of the monitoring system is achieved by AutoMonitor, a high-level coordinator application provided by the Illinois SHM Project Services Toolsuite. The monitoring system also features power harvesting enabled by solar panels attached to each sensor node and AutoMonitor for charging control. The proposed wireless system has been deployed on the Jindo Bridge, a cable-stayed bridge located in South Korea. Tension forces are autonomously monitored for 12 cables in the east, land side of the bridge, proving the validity and potential of the presented tension monitoring system for real-world applications.

  3. A study of the applicability of a straw-fired batch boiler as a heat source for a small-scale cogeneration unit

    Directory of Open Access Journals (Sweden)

    Sornek Krzysztof

    2016-12-01

    Full Text Available Straw-fired batch boilers, due to their relatively simple structure and low operating costs, are an excellent source of heat for a wide range of applications. A concept prototype of a cogeneration system with a straw-fired batch boiler was developed. The basic assumptions were based on the principles of the Rankine Cycle and the Organic Rankine Cycle systems with certain design modifications. Using the prototype design of a system that collects high-temperature heat from the boiler, studies were performed. The studies involved an analysis of the flue gas temperature distribution in the area of the oil exchanger, a comparison of the instantaneous power of the boiler’s water and oil circuits for different modes of operation, as well as an analysis of the flue gas. In the proposed system configuration where the electricity production supplements heat generation, the power in the oil circuit may be maintained at a constant level of approx. 20-30 kW. This is possible provided that an automatic fuel supply system is applied. Assuming that the efficiency of the electricity generation system is not less than 10%, it will be possible to generate 2-3 kW of electricity. This value will be sufficient, for an on-site operation of the boiler.

  4. Large-scale biodiesel production using flue gas from coal-fired power plants with Nannochloropsis microalgal biomass in open raceway ponds.

    Science.gov (United States)

    Zhu, Baohua; Sun, Faqiang; Yang, Miao; Lu, Lin; Yang, Guanpin; Pan, Kehou

    2014-12-01

    The potential use of microalgal biomass as a biofuel source has raised broad interest. Highly effective and economically feasible biomass generating techniques are essential to realize such potential. Flue gas from coal-fired power plants may serve as an inexpensive carbon source for microalgal culture, and it may also facilitate improvement of the environment once the gas is fixed in biomass. In this study, three strains of the genus Nannochloropsis (4-38, KA2 and 75B1) survived this type of culture and bloomed using flue gas from coal-fired power plants in 8000-L open raceway ponds. Lower temperatures and solar irradiation reduced the biomass yield and lipid productivities of these strains. Strain 4-38 performed better than the other two as it contained higher amounts of triacylglycerols and fatty acids, which are used for biodiesel production. Further optimization of the application of flue gas to microalgal culture should be undertaken. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Offshore wind farm electrical cable layout optimization

    Science.gov (United States)

    Pillai, A. C.; Chick, J.; Johanning, L.; Khorasanchi, M.; de Laleu, V.

    2015-12-01

    This article explores an automated approach for the efficient placement of substations and the design of an inter-array electrical collection network for an offshore wind farm through the minimization of the cost. To accomplish this, the problem is represented as a number of sub-problems that are solved in series using a combination of heuristic algorithms. The overall problem is first solved by clustering the turbines to generate valid substation positions. From this, a navigational mesh pathfinding algorithm based on Delaunay triangulation is applied to identify valid cable paths, which are then used in a mixed-integer linear programming problem to solve for a constrained capacitated minimum spanning tree considering all realistic constraints. The final tree that is produced represents the solution to the inter-array cable problem. This method is applied to a planned wind farm to illustrate the suitability of the approach and the resulting layout that is generated.

  6. Water-tree resistant cable formulations

    Energy Technology Data Exchange (ETDEWEB)

    Sarma, H.; Dobbin, C.J.B.

    1992-10-06

    Polyethylene compositions are disclosed which are suitable for use as cable insulation for high voltage power distribution cables and, more particularly, contain an additive to inhibit the propagation of water trees in the insulation. The polyethylene composition of the invention is obtained by cross-linking a composition comprising ca 95 wt % of a low-density crosslinkable polyethylene and at least 1 wt % of a hydrolyzed terpolymer of ethylene, vinyl acetate, and vinyl alcohol. The terpolymer is obtained from the at least 95% hydrolysis of an ethylene-vinyl acetate copolymer having a 20-30 wt % vinyl acetate content. The polyethylene and the terpolymer have a substantially similar melt index. Tests conducted to evaluate insulation compositions of the invention are described. 1 fig., 4 tabs.

  7. Development of polymer packaging for power cable

    Directory of Open Access Journals (Sweden)

    S. Sremac

    2014-10-01

    Full Text Available This paper discusses the issues of product design and the procedure of developing polymer packaging as one of the most important engineering tasks. For the purpose of packing power cables a polymer packaging has been designed in the form of drum. Packaging and many other consumer products are largely produced using polymeric materials due to many positive features. High Density Polyethylene is the type of polyethylene proposed for packaging purposes due to its low degree of branching and strong intermolecular forces. Transport and storage processes were automated based on the radio-frequency identification technology. The proposed system is flexible in terms of its possibility of accepting and processing different types of cables and other products.

  8. Commercialization of Medium Voltage HTS Triax TM Cable Systems

    Energy Technology Data Exchange (ETDEWEB)

    Knoll, David

    2012-12-31

    The original project scope that was established in 2007 aimed to install a 1,700 meter (1.1 mile) medium voltage HTS Triax{TM} cable system into the utility grid in New Orleans, LA. In 2010, however, the utility partner withdrew from the project, so the 1,700 meter cable installation was cancelled and the scope of work was reduced. The work then concentrated on the specific barriers to commercialization of HTS cable technology. The modified scope included long-length HTS cable design and testing, high voltage factory test development, optimized cooling system development, and HTS cable life-cycle analysis. In 2012, Southwire again analyzed the market for HTS cables and deemed the near term market acceptance to be low. The scope of work was further reduced to the completion of tasks already started and to testing of the existing HTS cable system in Columbus, OH. The work completed under the project included: • Long-length cable modeling and analysis • HTS wire evaluation and testing • Cable testing for AC losses • Optimized cooling system design • Life cycle testing of the HTS cable in Columbus, OH • Project management. The 200 meter long HTS Triax{TM} cable in Columbus, OH was incorporated into the project under the initial scope changes as a test bed for life cycle testing as well as the site for an optimized HTS cable cooling system. The Columbus cable utilizes the HTS TriaxTM design, so it provided an economical tool for these of the project tasks.

  9. Smart synthetic material arresting cable based on embedded distributed fiber optic sensors

    Science.gov (United States)

    Mendoza, Edgar; Prohaska, John; Kempen, Cornelia; Bentley, Douglas; Murdock, Chad; Piatkowski, David; White, Lonnie

    2007-07-01

    Redondo Optics Inc. in collaboration with the Cortland Cable Company and the US. Navy under a Navy sponsored SBIR program is in the process of developing an embedded distributed fiber optic sensor (EDIFOS TM) system for the real-time, structural health monitoring, damage assessment, and lifetime prediction of full scale synthetic material arresting gear cables. The EDIFOS TM system uses a distributed array of fiber Bragg grating sensors, sensitive to stress/strain, impact damage, kinking and bending, and temperature, embedded within the strands of a synthetic material arresting cable structure. Fiber Bragg grating sensors are a mature technology typically used for the in-situ structural health monitoring of advanced structures. The periodic grating produces an optical, wavelength-encoded signal whose properties are dependent on the structural, and mechanical environment of the sensor fiber. The FBG sensor interrogation system monitors the status of each of the individual FBG sensors distributed along the embedded sensor fibers and transforms this information in real-time in to a graphical display of the stress/strain and temperature state of the entire arresting gear cable. An alarm system triggers to pinpoint those locations of potential damage.

  10. 500 kV oil-filled cable installed on bridges

    Energy Technology Data Exchange (ETDEWEB)

    Minemura, S.; Maekawa, Y. (Electric Power Development Co. Ltd., Tokyo (Japan))

    1990-04-01

    The 220 kV Ch{bar u}si Trunk Line, now transmitting a maximum of 300 MW of electricity between the Ch{bar u}goku area of Honsh{bar u} and Shikoku island, is expected to be inadequate in the 1990's due to the rise in electrical demand. Therefore, to strengthen this interconnection, a new 500 kV transmission line was proposed. The most significant feature of this transmission line is the installation of 500 kV cables along the bridges (the Seto Ohashi Bridge) which span the Inland Sea (Seto). This is the first 500 kV long-distance transmission cable line. It is also the first large-scale cable line in the world installed along various types of bridges (ten bridges; route length of the bridge portion approximately 8 km). This paper gives an outline of the Honsh{bar u}---Shikoku interconnecting transmission line and also presents some technical features concerning 500 kV cables.

  11. Occupational Asthma in a Cable Manufacturing Company

    Science.gov (United States)

    Attarchi, Mirsaeed; Dehghan, Faezeh; Yazdanparast, Taraneh; Mohammadi, Saber; Golchin, Mahdie; Sadeghi, Zargham; Moafi, Masoud; Seyed Mehdi, Seyed Mohammad

    2014-01-01

    Background: During the past decade, incidence of asthma has increased, which might have been due to environmental exposures. Objectives: Considering the expansion of cable manufacturing industry in Iran, the present study was conducted to evaluate the prevalence of occupational asthma in a cable manufacturing company in Iran as well as its related factors. Patients and Methods: This study was conducted on employees of a cable manufacturing company in Yazd, Iran, in 2012. The workers were divided into two groups of exposure (to toluene diisocyanate, polyvinyl chloride, polyethylene or polypropylene) and without exposure. Diagnosis of occupational asthma was made based on the subjects’ medical history, spirometry and peak flowmetry, and its frequency was compared between the two groups. Results: The overall prevalence of occupational asthma was 9.7%. This rate was 13.8% in the exposed group. Logistic regression analysis showed that even after adjustment for confounding factors, a significant correlation existed between the frequency of occupational asthma and exposure to the produced dust particles (P < 0.05). In addition, age, work experience, body mass index, cigarette smoking and shift work had significant correlations with the prevalence of occupational asthma (P < 0.05). Conclusions: Considering the high prevalence of occupational asthma among cable manufacturing company workers in Iran, this issue needs to be addressed immediately in addition to reduction of exposure among subjects. Reduction in work shift duration, implementation of tobacco control and cessation programs for the personnel, and performing spirometry tests and respiratory examinations in shorter periods may be among effective measures for reducing the incidence of occupational asthma in this industry. PMID:25558389

  12. Influence of fire barriers on fire performance of facades with combustible insulation

    Directory of Open Access Journals (Sweden)

    Bjegovic Dubravka

    2016-01-01

    Full Text Available In today's modern society sustainability has become a key driver for innovation. Sustainability in buildings is, or at least it should be, strongly interconnected with energy efficiency and fire safety. Unfortunately, cases of fires in buildings all over the world are a wakeup call to start thinking of fire safety as an inevitable part of energy efficiency in buildings. Thermally enhanced building envelopes, due to materials used, can represent significantly increased fire load on façades. To determine their fire performance, it is necessary to move on from material level to the whole building level, i.e. full scale tests. This paper presents findings from comprehensive research on influence of fire barrier on fire performance of External Thermal Insulation Composite System – ETICS with combustible thermal insulation. To confirm findings, tests on identical ETICS systems were conducted in March 2014 and May 2014.

  13. Examining cable plant bandwidth for FDDI

    Science.gov (United States)

    Hayes, James E.

    1991-02-01

    Networks designed around the ANSI X3T9. 5 standard called Fiber Distributed Data Interface (FDDI) are limited in distance by the bandwidth not the attenuation of the fiber optic cable. The magnitude of this limitation is defined and potential options in sources and fibers are examined. Since FDDI is limited in distance by the bandwidth of the cable plant not the attenuation many end users have put a bandwidth specification in their fiber optic cable purchase specifications. Some have even specified testing for bandwidth. This has caused much controversy between vendors installers and users. As a test equipment vendor we have " refereed" quite a few of these already and we have found that more myths are believed than realities are understood. What Limits Fiber Bandwidth? Two things limit fiber bandwidth: modal dispersion and chromatic dispersion. Modal dispersion is caused by the fact that the graded index profile of the fiber isn''t perfect so all modes do not have exactly the same transit time through the fiber. Chromatic dispersion is caused by the fact that the velocity of light in the fiber is dependent on the wavelength of the fiber. Fibers are designed for a zero dispersion wavelength light of any other wavelength will have some dispersion. Sources of wide spectral width like LEDs will suffer from more dispersion than narrow spectral width sources like laser diodes. In most circumstances one can

  14. Occupational asthma in a cable manufacturing company.

    Science.gov (United States)

    Attarchi, Mirsaeed; Dehghan, Faezeh; Yazdanparast, Taraneh; Mohammadi, Saber; Golchin, Mahdie; Sadeghi, Zargham; Moafi, Masoud; Seyed Mehdi, Seyed Mohammad

    2014-10-01

    During the past decade, incidence of asthma has increased, which might have been due to environmental exposures. Considering the expansion of cable manufacturing industry in Iran, the present study was conducted to evaluate the prevalence of occupational asthma in a cable manufacturing company in Iran as well as its related factors. This study was conducted on employees of a cable manufacturing company in Yazd, Iran, in 2012. The workers were divided into two groups of exposure (to toluene diisocyanate, polyvinyl chloride, polyethylene or polypropylene) and without exposure. Diagnosis of occupational asthma was made based on the subjects' medical history, spirometry and peak flowmetry, and its frequency was compared between the two groups. The overall prevalence of occupational asthma was 9.7%. This rate was 13.8% in the exposed group. Logistic regression analysis showed that even after adjustment for confounding factors, a significant correlation existed between the frequency of occupational asthma and exposure to the produced dust particles (P company workers in Iran, this issue needs to be addressed immediately in addition to reduction of exposure among subjects. Reduction in work shift duration, implementation of tobacco control and cessation programs for the personnel, and performing spirometry tests and respiratory examinations in shorter periods may be among effective measures for reducing the incidence of occupational asthma in this industry.

  15. Crown Fire Potential

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — Crown fire potential was modeled using FlamMap, an interagency fire behavior mapping and analysis program that computes potential fire behavior characteristics. The...

  16. Fire safety at home

    Science.gov (United States)

    ... over the smoke alarm as needed. Using a fire extinguisher can put out a small fire to keep it from getting out of control. Tips for use include: Keep fire extinguishers in handy locations, at least one on ...

  17. Fire Ant Bites

    Science.gov (United States)

    ... Favorite Name: Category: Share: Yes No, Keep Private Fire Ant Bites Share | Fire ants are aggressive, venomous insects that have pinching ... across the United States, even into Puerto Rico. Fire ant stings usually occur on the feet or ...

  18. Fire Ant Allergy

    Science.gov (United States)

    ... Treatments ▸ Library ▸ Allergy Library ▸ Fire ant allergy Share | Fire Ant Allergy This article has been reviewed by Thanai Pongdee, MD, FAAAAI Fire ants are a stinging insect typically found in ...

  19. 46 CFR 28.820 - Fire pumps, fire mains, fire hydrants, and fire hoses.

    Science.gov (United States)

    2010-10-01

    ..., fire hydrants, and fire hoses. (a) Each vessel must be equipped with a self-priming, power driven fire...) If multiple pumps are installed, they may be used for other purposes provided at least one pump is...

  20. Hybrid modeling for dynamic analysis of cable-pulley systems with time-varying length cable and its application

    Science.gov (United States)

    Wang, Jing; Qi, Zhaohui; Wang, Gang

    2017-10-01

    The dynamic analysis of cable-pulley systems is investigated in this paper, where the time-varying length characteristic of the cable as well as the coupling motion between the cable and the pulleys are considered. The dynamic model for cable-pulley systems are presented based on the principle of virtual power. Firstly, the cubic spline interpolation is adopted for modeling the flexible cable elements and the virtual 1powers of tensile strain, inertia and gravity forces on the cable are formulated. Then, the coupled motions between the cable and the movable or fixed pulley are described by the input and output contact points, based on the no-slip assumption and the spatial description. The virtual powers of inertia, gravity and applied forces on the contact segment of the cable, the movable and fixed pulleys are formulated. In particular, the internal node degrees of freedom of spline cable elements are reduced, which results in that only the independent description parameters of the nodes connected to the pulleys are included in the final governing dynamic equations. At last, two cable-pulley lifting mechanisms are considered as demonstrative application examples where the vibration of the lifting process is investigated. The comparison with ADAMS models is given to prove the validity of the proposed method.

  1. 47 CFR 1.1155 - Schedule of regulatory fees and filing locations for cable television services.

    Science.gov (United States)

    2010-10-01

    ... locations for cable television services. 1.1155 Section 1.1155 Telecommunication FEDERAL COMMUNICATIONS... Schedule of regulatory fees and filing locations for cable television services. Fee amount Address 1. Cable Television Relay Service $315 FCC, Cable, P.O. Box 979084, St. Louis, MO 63197-9000 2. Cable TV System (per...

  2. Modeling Cable and Guide Channel Interaction in a High-Strength Cable-Driven Continuum Manipulator

    Science.gov (United States)

    Moses, Matthew S.; Murphy, Ryan J.; Kutzer, Michael D. M.; Armand, Mehran

    2016-01-01

    This paper presents several mechanical models of a high-strength cable-driven dexterous manipulator designed for surgical procedures. A stiffness model is presented that distinguishes between contributions from the cables and the backbone. A physics-based model incorporating cable friction is developed and its predictions are compared with experimental data. The data show that under high tension and high curvature, the shape of the manipulator deviates significantly from a circular arc. However, simple parametric models can fit the shape with good accuracy. The motivating application for this study is to develop a model so that shape can be predicted using easily measured quantities such as tension, so that real-time navigation may be performed, especially in minimally-invasive surgical procedures, while reducing the need for hazardous imaging methods such as fluoroscopy. PMID:27818607

  3. Antenna mechanism of length control of actin cables

    CERN Document Server

    Mohapatra, Lishibanya; Kondev, Jane

    2014-01-01

    Actin cables are linear cytoskeletal structures that serve as tracks for myosin-based intracellular transport of vesicles and organelles in both yeast and mammalian cells. In a yeast cell undergoing budding, cables are in constant dynamic turnover yet some cables grow from the bud neck toward the back of the mother cell until their length roughly equals the diameter of the mother cell. This raises the question: how is the length of these cables controlled? Here we describe a novel molecular mechanism for cable length control inspired by recent experimental observations in cells. This antenna mechanism involves three key proteins: formins, which polymerize actin, Smy1 proteins, which bind formins and inhibit actin polymerization, and myosin motors, which deliver Smy1 to formins, leading to a length-dependent actin polymerization rate. We compute the probability distribution of cable lengths as a function of several experimentally tuneable parameters such as the formin-binding affinity of Smy1 and the concentra...

  4. Guy cable design and damping for vertical axis wind turbines

    Science.gov (United States)

    Carne, T. G.

    1981-01-01

    Guy cables are frequently used to support vertical axis wind turbines since guying the turbine reduces some of the structural requirements on the tower. The guys must be designed to provide both the required strength and the required stiffness at the top of the turbine. The axial load which the guys apply to the tower, bearings, and foundations is an undesirable consequence of using guys to support the turbine. Limiting the axial load so that it does not significantly affect the cost of the turbine is an important objective of the cable design. The lateral vibrations of the cables is another feature of the cable design which needs to be considered. These aspects of the cable design are discussed, and a technique for damping cable vibrations was mathematically analyzed and demonstrated with experimental data.

  5. Dynamic wind effects on suspension and cable-stayed bridges

    Science.gov (United States)

    Larsen, Allan; Larose, Guy L.

    2015-01-01

    Cable supported bridges are flexible structures which may be excited into oscillations by the wind. The excitation forces acting on cable supported bridges are aerodynamic by nature, but are for a large part set into play by the underlying structural dynamics of the bridge structures. The paper discusses the various types of dynamic wind effects commonly encountered for suspension and cable-stayed bridges emphasizing the importance of the structural dynamics.

  6. Distance Protection of Cross-Bonded Transmission Cable-Systems

    OpenAIRE

    Bak, Claus Leth; F. Jensen, Christian

    2014-01-01

    In this paper the problems of protecting a cross-bonded cable system using distance protection are analysed. The combination of the desire to expand the high voltage transmission grid and the public's opinion towards new installations of overhead lines (OHL), more and more transmission cable systems are being laid around the world. Differential protection is often used for the main protection of cables. As a backup protection, distance protection is very often the preferred choice. Therefore,...

  7. Modeling opportunities and feasibility of siting wood-fired electrical generating facilities to facilitate landscape-scale fuel treatment with FIA BioSum.

    Science.gov (United States)

    Jeremy S. Fried; Glenn Christensen; Dale Weyermann; R. Jamie Barbour; Roger Fight; Bruce Hiserote; Guy. Pinjuv

    2005-01-01

    Utilization of small diameter trees is viewed by many as the key to making landscape-scale fuel treatment financially feasible. But little capacity currently exists for utilizing such material and capacity of sufficient scale to have a significant impact on the economics of small diameter removals will only be added if predictable feedstocks can be assured. The FIA...

  8. Fire and fire ecology: Concepts and principles

    Science.gov (United States)

    Mark A. Cochrane; Kevin C. Ryan

    2009-01-01

    Fire has been central to terrestrial life ever since early anaerobic microorganisms poisoned the atmosphere with oxygen and multicellular plant life moved onto land. The combination of fuels, oxygen, and heat gave birth to fire on Earth. Fire is not just another evolutionary challenge that life needed to overcome, it is, in fact, a core ecological process across much...

  9. Vehicle fires and fire safety in tunnels

    Science.gov (United States)

    2002-09-20

    Tunnels present what is arguably the most hazardous environment, from the point of view of fire safety, that members of the public ever experience. The fire safety design of tunnels is carried out by tunnel engineers on the basis of a potential fire ...

  10. Fire Service Training. Portable Fire Extinguishers. (Revised).

    Science.gov (United States)

    North Carolina State Dept. of Community Colleges, Raleigh.

    One of a set of fourteen instructional outlines for use in a course to train novice firemen, this guide covers the topic of portable fire extinguishers. Designed to be used with the Robert J. Brady Transparencies and/or the film "Portable Fire Extinguishers" and with the International Fire Service Training Association Manual No. 101,…

  11. The Performance of Aircraft Control Cables Under Service Conditions

    Science.gov (United States)

    1976-04-01

    wires in the cables is illustr;tcd in Ifigs. I ald 2. Fatigue tests were also carried out on samples of galvanised steel cable (5 cwt. (2.49kN) minimumil...sheave ratio using the MIL-C-151I cable of 2.38 mm (3:32 in.) diameter would have been 13.3. For a satisfactory fatigue performance for 7 x 19 galvanised ...critical region in which cable life is relatively low". Reference 13 recommends a sheave ratio of 18 for 7 x 19 galvanised and stainless ,ables and a

  12. Strand critical current degradation in $Nb_{3}$ Sn Rutherford cables

    CERN Document Server

    Barzi, E; Higley, H C; Scanlan, R M; Yamada, R; Zlobin, A V

    2001-01-01

    Fermilab is developing 11 Tesla superconducting accelerator magnets based on Nb/sub 3/Sn superconductor. Multifilamentary Nb/sub 3/Sn strands produced using the modified jelly roll, internal tin, and powder-in-tube technologies were used for the development and test of the prototype cable. To optimize the cable geometry with respect to the critical current, short samples of Rutherford cable with packing factors in the 85 to 95% range were fabricated and studied. In this paper, the results of measurements of critical current, n-value and RRR made on the round virgin strands and on the strands extracted from the cable samples are presented. (5 refs).

  13. Simulations of a moored power cable at OBSEA platform

    OpenAIRE

    Prat Farran, Joana d'Arc; Río Fernandez, Joaquín del

    2013-01-01

    New green energy sources deployed at sea in mobile platforms use power cables in order to transport green energy at sea surface to the bottom. Theses power cables are exposed to the dynamic behaviour of the platform movements due to waves, currents and wind. OBSEA is a seafloor cabled observatory at 20 m depth in front of Vilanova, in Catalan coast. OBSEA captures data in real time like current, waves and wind among others. In this paper, a model of a moored power cable installed at OBS...

  14. A Cabled, High Bandwidth Instrument Platform for Continuous Scanning of the Upper Ocean Water Column

    Science.gov (United States)

    McRae, E.; Delaney, J. R.; Kelly, D.; Daly, K. L.; Luther, D. S.; Harkins, G.; Harrington, M.; McGuire, C.; Tilley, J.; Dosher, J.; Waite, P.; Cram, G.; Kawka, O. E.

    2016-02-01

    The Cabled Array portion of the National Science Foundation funded Ocean Observatories Initiative is a large scale, high bandwidth and high power subsea science network designed by the University of Washington Applied Physics Laboratory. Part of that system is a set of winched profilers which continuously scan the upper 200m of the ocean at their deployment sites. The custom built profilers leverage the Cabled Array's technology for interfacing collections of science instruments and add the ability to run predefined missions and to switch missions or mission parameters on the fly via command from shore. The profilers were designed to operate continuously for up to two years after deployment after which certain wearing components must be replaced. The data from the profiler's science and engineering sensors are streamed to shore via the seafloor network in real time. Data channel capacity from the profilers exceeds 40 Mbps. For profiler safety, mission execution is controlled within the platform. Inputs such as 3D gyro, pressure depth and deployed cable calculations are monitored to assure safe operation during any sea state. The profilers never surface but are designed to approach within 5m of the surface if conditions allow. Substantial engineering effort was focused on reliable cable handling under all ocean conditions. The profilers are currently operated from subsea moorings which also contain sets of fixed science and engineering sensors. The profilers and their associated mooring instrument assemblies are designed for rapid replacement using ROVs. We have operated this system for two years, including one annual maintenance turn and information relative to that experience will be included in the paper.[Image Caption] Cabled Array Shallow Profiler shown in its parking position.

  15. Continuing and New Measurements at the Abyssal ALOHA Cabled Observatory

    Science.gov (United States)

    Howe, B. M.; Potemra, J. T.; Butler, R.; Santiago-Mandujano, F.; Lukas, R.; Duennebier, F. K.; Karl, D. M.; Aucan, J.

    2016-02-01

    The ALOHA Cabled Observatory (ACO) is a general purpose "node" providing power, communications and timing connectivity for science use at Station ALOHA 100 km north of Oahu. Included are a suite of basic sensors making core measurements, some local and some sensing the water column. At 4728 m deep, it is the deepest scientific outpost on the planet with power and Internet. Importantly, Station ALOHA is the field site of the NSF-funded Hawaii Ocean Time-series (HOT) program that has investigated temporal dynamics in biology, physics, and chemistry since 1988, at a site that is representative of roughly 70% of the world ocean, sampling the ocean from top to bottom to monitor and study changes on scales of months to decades. The co-located Woods Hole mooring (WHOTS) provides meteorological and upper ocean physical data. The CMORE (Center for Microbial Oceanography Research and Education) and SCOPE (Simons Collaboration on Ocean Processes and Ecology) programs address their respective science topics at ALOHA. Together these programs provide a truly unique means for observing the ocean across all disciplines and regimes (deep sea, near surface, etc.). ACO has been operating in the abyss since June 2011, collecting temperature, salinity, velocity, acoustic, and video data (see for instance the abstract by Lukas et al., Spatial Analysis of Abyssal Temperature Variations Observed from the ALOHA Cabled Observatory and WHOTS Moorings). Using the University of Hawaii remotely operated vehicle ROV Lu`ukai, a basic sensor package was recently installed equipped with a Paroscientific nano-resolution pressure sensor, a WetLabs fluorometer/turbidity sensor, and a Seabird CTDO2 instrument. These data will be presented and described.

  16. Numerical Study of the Active Tendon Control of a Cable-Stayed Bridge in a Construction Phase

    Directory of Open Access Journals (Sweden)

    M. H. El Ouni

    2014-01-01

    Full Text Available This paper investigates numerically the active tendon control of a cable-stayed bridge in a construction phase. A linear Finite Element model of small scale mock-up of the bridge is first presented. Active damping is added to the structure by using pairs of collocated force actuator-displacement sensors located on each active cable and decentralized first order positive position feedback (PPF or direct velocity feedback (DVF. A comparison between these two compensators showed that each one has good performance for some modes and performs inadequately with the other modes. A decentralized parallel PPF-DVF is proposed to get the better of the two compensators. The proposed strategy is then compared to the one using decentralized integral force feedback (IFF and showed better performance. The Finite Element model of the bridge is coupled with a nonlinear cable taking into account sag effect, general support movements, and quadratic and cubic nonlinear couplings between in-plane and out-of-plane motions. Finally, the proposed strategy is used to control both deck and cable vibrations induced by parametric excitation. Both cable and deck vibrations are attractively damped.

  17. Wildland fire probabilities estimated from weather model-deduced monthly mean fire danger indices

    Science.gov (United States)

    Haiganoush K. Preisler; Shyh-Chin Chen; Francis Fujioka; John W. Benoit; Anthony L. Westerling

    2008-01-01

    The National Fire Danger Rating System indices deduced from a regional simulation weather model were used to estimate probabilities and numbers of large fire events on monthly and 1-degree grid scales. The weather model simulations and forecasts are ongoing experimental products from the Experimental Climate Prediction Center at the Scripps Institution of Oceanography...

  18. FireFly: reconfigurable optical wireless networking data centers

    Science.gov (United States)

    Kavehrad, Mohsen; Deng, Peng; Gupta, H.; Longtin, J.; Das, S. R.; Sekar, V.

    2017-01-01

    We explore a novel, free-space optics based approach for building data center interconnects. Data centers (DCs) are a critical piece of today's networked applications in both private and public sectors. The key factors that have driven this trend are economies of scale, reduced management costs, better utilization of hardware via statistical multiplexing, and the ability to elastically scale applications in response to changing workload patterns. A robust DC network fabric is fundamental to the success of DCs and to ensure that the network does not become a bottleneck for high-performance applications. In this context, DC network design must satisfy several goals: high performance (e.g., high throughput and low latency), low equipment and management cost, robustness to dynamic traffic patterns, incremental expandability to add new servers or racks, and other practical concerns such as cabling complexity, and power and cooling costs. Current DC network architectures do not seem to provide a satisfactory solution, with respect to the above requirements. In particular, traditional static (wired) networks are either overprovisioned or oversubscribed. Recent works have tried to overcome the above limitations by augmenting a static (wired) "core" with some flexible links (RF-wireless or optical). These augmented architectures show promise, but offer only incremental improvement in performance. Specifically, RFwireless based augmented solutions also offer only limited performance improvement, due to inherent interference and range constraints of RF links. This paper explores an alternative design point—a fully flexible and all-wireless DC interrack network based on free-space optical (FSO) links. We call this FireFly as in; Free-space optical Inter-Rack nEtwork with high FLexibilitY. We will present our designs and tests using various configurations that can help the performance and reliability of the FSO links.

  19. Use of expert knowledge to develop fuel maps for wildland fire management [chapter 11

    Science.gov (United States)

    Robert E. Keane; Matt Reeves

    2012-01-01

    Fuel maps are becoming an essential tool in fire management because they describe, in a spatial context, the one factor that fire managers can control over many scales ­ surface and canopy fuel characteristics. Coarse-resolution fuel maps are useful in global, national, and regional fire danger assessments because they help fire managers effectively plan, allocate, and...

  20. A review of challenges to determining and demonstrating efficiency of large fire management

    Science.gov (United States)

    Matthew P. Thompson; Francisco Rodriguez y Silva; David E. Calkin; Michael S. Hand

    2017-01-01

    Characterising the impacts of wildland fire and fire suppression is critical information for fire management decision-making. Here, we focus on decisions related to the rare larger and longer-duration fire events, where the scope and scale of decision-making can be far broader than initial response efforts, and where determining and demonstrating efficiency of...