Science.gov

Sample records for pipe burst problems

  1. Analysis of chlorinated polyvinyl chloride pipe burst problems :Vasquez residence system inspection.

    SciTech Connect

    Black, Billy D.; Menicucci, David F.; Harrison, John

    2005-10-01

    This report documents the investigation regarding the failure of CPVC piping that was used to connect a solar hot water system to standard plumbing in a home. Details of the failure are described along with numerous pictures and diagrams. A potential failure mechanism is described and recommendations are outlined to prevent such a failure.

  2. Pipes Conveying Fluid: A Model Dynamical Problem

    NASA Astrophysics Data System (ADS)

    Païdoussis, M. P.; Li, G. X.

    1993-02-01

    This paper reviews the dynamics of pipes conveying fluid and presents a selective review of the research undertaken on it. It is endeavoured to show that this system is fast becoming a new paradigm in dynamics, on a par with, for instance, the classical problem of the column subjected to compressive loading, but one capable of displaying much richer dynamical behaviour. The dynamics of pipes with supported ends, cantilevered pipes or with unusual boundary conditions; continuously flexible pipes or articulated ones; pipe conveying incompressible or compressible fluid, with steady or unsteady flow velocity; pipes thin enough to be treated as thin shells; linear, nonlinear and chaotic dynamics; these and many more are some of the aspects of the problem considered. An Appendix is provided for those unfamiliar with the modern methods of nonlinear analysis.

  3. Piping benchmark problems for the Westinghouse AP600 Standardized Plant

    SciTech Connect

    Bezler, P.; DeGrassi, G.; Braverman, J.; Wang, Y.K.

    1997-01-01

    To satisfy the need for verification of the computer programs and modeling techniques that will be used to perform the final piping analyses for the Westinghouse AP600 Standardized Plant, three benchmark problems were developed. The problems are representative piping systems subjected to representative dynamic loads with solutions developed using the methods being proposed for analysis for the AP600 standard design. It will be required that the combined license licensees demonstrate that their solutions to these problems are in agreement with the benchmark problem set.

  4. Ductile fracture propagation in gas pipelines - results of full scale burst tests of big diameter pipes

    SciTech Connect

    de Vito, A.; Morini, A.; Pozzi, A.; Bonomo, F.; Bramante, M.

    1981-01-01

    Full-scale burst tests have been conducted at Perdasdefogu station of 48- and 56-in. diameter pipes of grade X70 and X80; hoop stresses were between 317 and 385 N/sq mm and thicknesses between 17 and 20 m. Two types of materials have been examined and other aspects have been considered. Particular efforts have been devoted to deformation measured by strain gages. From results obtained, examined also using a new formula as a prevision arrest criterion, the following conclusions can be drawn: (1) behavior of Q.T. materials is not properly covered by current design criteria, related limit cv energy values predicting arrest appear in fact unsafe for Q.T. steels; (2) frozen backfill might play an important role in containing fracture; and (3) simple mechanical devices can act, if properly designed, as very efficient crack-arrestors. 10 references.

  5. How to handle stuck pipe and fishing problems

    SciTech Connect

    Brouse, M.

    1982-11-01

    Discusses causes, symptoms, ways to prevent and methods for freeing differentially stuck strings. Presents 3 specific techniques for breaking the pipe-formation bond in detail. Includes all necessary formulas and calculation procedures that involve only simple arithmetic. Written for use by supervisory rig personnel who are faced with stuck pipe and fishing operations which continue to represent serious and expensive problems in drilling operations, particularly in today's deeper, higher pressure, and potentially more hazardous well environments. Points out that differentially stuck pipe is almost always associated with one or more of the following conditions: hydrostatic mud pressure in the well bore is greater than the formation pore pressure opposite the stuck point interval; the formation opposite the stuck point interval is usually a porous and permeable sand, limestone, or dolomite; a thick, poor and undesirable filter cake has built up across the formation which allows a differential pressure (i.e. spurt loss) to occur rapidly; pipe has been left stationary for several minutes opposite porous and permeable zones whereby a fairly large pipe contact area is against the formation; there is free circulation around the stuck zone; and a slight seepage or partial mud loss to the formation occurred prior to getting stuck.

  6. Identification of significant problems related to light water reactor piping systems

    SciTech Connect

    1980-07-01

    Work on the project was divided into three tasks. In Task 1, past surveys of LWR piping system problems and recent Licensee Event Report summaries are studied to identify the significant problems of LWR piping systems and the primary causes of these problems. Pipe cracking is identified as the most recurring problem and is mainly due to the vibration of pipes due to operating pump-pipe resonance, fluid-flow fluctuations, and vibration of pipe supports. Research relevant to the identified piping system problems is evaluated. Task 2 studies identify typical LWR piping systems and the current loads and load combinations used in the design of these systems. Definitions of loads are reviewed. In Task 3, a comparative study is carried out on the use of nonlinear analysis methods in the design of LWR piping systems. The study concludes that the current linear-elastic methods of analysis may not predict accurately the behavior of piping systems under seismic loads and may, under certain circumstances, result in nonconservative designs. Gaps at piping supports are found to have a significant effect on the response of the piping systems.

  7. How to handle stuck pipe and fishing problems

    SciTech Connect

    Brouse, M.

    1982-12-01

    In a previous paper, causes, prevention and methods for freeing differentially stuck pipe were discussed. This article presents similar information and methods for dealing with mechanically stuck pipe including tubular stretch techniques and free point/back off operations.

  8. Sonic limitations and startup problems of heat pipes

    NASA Technical Reports Server (NTRS)

    Deverall, J. E.; Kemme, J. E.; Florschuetz, L. W.

    1972-01-01

    Introduction of small amounts of inert, noncombustible gas aids startup in certain types of heat pipes. When the heat pipe is closely coupled to the heat sink, the startup system must be designed to bring the heat sink on-line slowly.

  9. Piping benchmark problems for the ABB/CE System 80+ Standardized Plant

    SciTech Connect

    Bezler, P.; DeGrassi, G.; Braverman, J.; Wang, Y.K.

    1994-07-01

    To satisfy the need for verification of the computer programs and modeling techniques that will be used to perform the final piping analyses for the ABB/Combustion Engineering System 80+ Standardized Plant, three benchmark problems were developed. The problems are representative piping systems subjected to representative dynamic loads with solutions developed using the methods being proposed for analysis for the System 80+ standard design. It will be required that the combined license licensees demonstrate that their solution to these problems are in agreement with the benchmark problem set. The first System 80+ piping benchmark is a uniform support motion response spectrum solution for one section of the feedwater piping subjected to safe shutdown seismic loads. The second System 80+ piping benchmark is a time history solution for the feedwater piping subjected to the transient loading induced by a water hammer. The third System 80+ piping benchmark is a time history solution of the pressurizer surge line subjected to the accelerations induced by a main steam line pipe break. The System 80+ reactor is an advanced PWR type.

  10. Methodological problems with gamma-ray burst hardness/intensity correlations

    NASA Technical Reports Server (NTRS)

    Schaefer, Bradley E.

    1993-01-01

    The hardness and intensity are easily measured quantities for all gamma-ray bursts (GRBs), and so, many past and current studies have sought correlations between them. This Letter presents many serious methodological problems with the practical definitions for both hardness and intensity. These difficulties are such that significant correlations can be easily introduced as artifacts of the reduction procedure. In particular, cosmological models of GRBs cannot be tested with hardness/intensity correlations with current instrumentation and the time evolution of the hardness in a given burst may be correlated with intensity for reasons that are unrelated to intrinsic change in the spectral shape.

  11. Clad piping - a novel approach for solving nuclear plant service water and erosion-corrosion problems

    SciTech Connect

    Chakravarti, B.

    1992-12-31

    This paper discusses the application of clad piping components to solve various nuclear plant corrosion problems, such as service water system corrosion and feedwater/condensate/steam erosion-corrosion. This approach uses a carbon steel piping component which has a metallurgically bonded alloy cladding on the ID. Different alloys are available as cladding, from stainless steels to Inconel 625, so that a specific alloy can be selected based on the service requirements. Clad piping components represent a novel approach, as they provide a mechanism to utilize resistant alloys to solve corrosion problems without affecting the plant design. Clad piping products are designed such that the carbon steel backing acts as the pressure boundary and the cladding the corrosion allowance. By selecting the proper carbon steel backing, the clad product can be engineered to allow {open_quotes}like-for-like{close_quotes} component replacement. The wall thickness, weight and stiffness of the piping would remain essentially the same. The thermal expansion coefficient of the bulk piping also remains the same. Thus, the piping design and layout is wholly unaffected, with no structural reanalysis being required. This paper discusses two applications where clad piping products are being applied for solving nuclear power plant corrosion problems. The first is in solving steam/condensate/feedwater erosion-corrosion. The second application is the utilization of Inconel 625 clad piping products for solving service water system corrosion. Clad piping products solve these problems while improving plant operation and performance by basically providing the benefits of the alloy without any of the accompanying disadvantages of redesign.

  12. Piping benchmark problems for the General Electric Advanced Boiling Water Reactor

    SciTech Connect

    Bezler, P.; DeGrassi, G.; Braverman, J.; Wang, Y.K.

    1993-08-01

    To satisfy the need for verification of the computer programs and modeling techniques that will be used to perform the final piping analyses for an advanced boiling water reactor standard design, three benchmark problems were developed. The problems are representative piping systems subjected to representative dynamic loads with solutions developed using the methods being proposed for analysis for the advanced reactor standard design. It will be required that the combined license holders demonstrate that their solutions to these problems are in agreement with the benchmark problem set.

  13. Foam pigs solve pipe cleaning problems offshore Brazil

    SciTech Connect

    Lima, P.C.R.; Neto, S.J.A.

    1995-10-02

    Pipeline systems in which conventional pigs cannot be run are common in such complex offshore installations as are found in Brazil`s Campos basin. These systems may contain changing pipe diameters or wet christmas trees and manifolds. A new concept for using low cost, low-density foam pigs for both liquid removal in wet-gas pipelines and paraffin removal in oil and multiphase pipelines has been successfully tested offshore Brazil. Although the present discussion focuses on condensate and paraffin removal in pipelines, the principles can be applied to several kinds of operations including general pipeline cleaning, product removal or separation in pipeline, corrosion evaluation, and chemical product application.

  14. TOPAZ - the transient one-dimensional pipe flow analyzer: code validation and sample problems

    SciTech Connect

    Winters, W.S.

    1985-10-01

    TOPAZ is a ''user friendly'' computer code for modeling the one-dimensional-transient physics of multi-species gas transfer in arbitrary arrangements of pipes, valves, vessels, and flow branches. This document presents a series of sample problems designed to aid potential users in creating TOPAZ input files. To the extent possible, sample problems were selected for which analytical solutions currently exist. TOPAZ comparisons with such solutions are intended to provide a measure of code validation.

  15. Piping benchmark problems. Volume 1. Dynamic analysis uniform support motion response spectrum method

    SciTech Connect

    Bezler, P.; Hartzman, M.; Reich, M.

    1980-08-01

    A set of benchmark problems and solutions have been developed for verifying the adequacy of computer programs used for dynamic analysis and design of nuclear piping systems by the Response Spectrum Method. The problems range from simple to complex configurations which are assumed to experience linear elastic behavior. The dynamic loading is represented by uniform support motion, assumed to be induced by seismic excitation in three spatial directions. The solutions consist of frequencies, participation factors, nodal displacement components and internal force and moment components. Solutions to associated anchor point motion static problems are not included.

  16. OTEC cold water pipe design for problems caused by vortex-excited oscillations

    SciTech Connect

    Griffin, O. M.

    1980-03-14

    Vortex-excited oscillations of marine structures result in reduced fatigue life, large hydrodynamic forces and induced stresses, and sometimes lead to structural damage and to diestructive failures. The cold water pipe of an OTEC plant is nominally a bluff, flexible cylinder with a large aspect ratio (L/D = length/diameter), and is likely to be susceptible to resonant vortex-excited oscillations. The objective of this report is to survey recent results pertaining to the vortex-excited oscillations of structures in general and to consider the application of these findings to the design of the OTEC cold water pipe. Practical design calculations are given as examples throughout the various sections of the report. This report is limited in scope to the problems of vortex shedding from bluff, flexible structures in steady currents and the resulting vortex-excited oscillations. The effects of flow non-uniformities, surface roughness of the cylinder, and inclination to the incident flow are considered in addition to the case of a smooth cyliner in a uniform stream. Emphasis is placed upon design procedures, hydrodynamic coefficients applicable in practice, and the specification of structural response parameters relevant to the OTEC cold water pipe. There are important problems associated with in shedding of vortices from cylinders in waves and from the combined action of waves and currents, but these complex fluid/structure interactions are not considered in this report.

  17. Evaluating Heat Pipe Performance in 1/6 g Acceleration: Problems and Prospects

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; McCollum, Timothy A.; Gibson, Marc A.; Sanzi, James L.; Sechkar, Edward A.

    2011-01-01

    Heat pipes composed of titanium and water are being considered for use in the heat rejection system of a fission power system option for lunar exploration. Placed vertically on the lunar surface, the heat pipes would operate as thermosyphons in the 1/6 g environment. The design of thermosyphons for such an application is determined, in part, by the flooding limit. Flooding is composed of two components, the thickness of the fluid film on the walls of the thermosyphon and the interaction of the fluid flow with the concurrent vapor counter flow. Both the fluid thickness contribution and interfacial shear contribution are inversely proportional to gravity. Hence, evaluating the performance of a thermosyphon in a 1 g environment on Earth may inadvertently lead to overestimating the performance of the same thermosyphon as experienced in the 1/6 g environment on the moon. Several concepts of varying complexity have been proposed for evaluating thermosyphon performance in reduced gravity, ranging from tilting the thermosyphons on Earth based on a cosine function, to flying heat pipes on a low-g aircraft. This paper summarizes the problems and prospects for evaluating thermosyphon performance in 1/6 g.

  18. Applications of Bayesian Statistics to Problems in Gamma-Ray Bursts

    NASA Technical Reports Server (NTRS)

    Meegan, Charles A.

    1997-01-01

    This presentation will describe two applications of Bayesian statistics to Gamma Ray Bursts (GRBS). The first attempts to quantify the evidence for a cosmological versus galactic origin of GRBs using only the observations of the dipole and quadrupole moments of the angular distribution of bursts. The cosmological hypothesis predicts isotropy, while the galactic hypothesis is assumed to produce a uniform probability distribution over positive values for these moments. The observed isotropic distribution indicates that the Bayes factor for the cosmological hypothesis over the galactic hypothesis is about 300. Another application of Bayesian statistics is in the estimation of chance associations of optical counterparts with galaxies. The Bayesian approach is preferred to frequentist techniques here because the Bayesian approach easily accounts for galaxy mass distributions and because one can incorporate three disjoint hypotheses: (1) bursts come from galactic centers, (2) bursts come from galaxies in proportion to luminosity, and (3) bursts do not come from external galaxies. This technique was used in the analysis of the optical counterpart to GRB970228.

  19. Basic problems and new potentials in monitoring sediment transport using Japanese pipe type geophone

    NASA Astrophysics Data System (ADS)

    Sakajo, Saiichi

    2016-04-01

    The authors have conducted a lot of series of monitoring of sediment transport by pipe type geophone in a model hydrological channel with various gradients and water discharge, using the various size of particles from 2 to 21 mm in the diameter. In the case of casting soils particle by particle into the water channel, 1,000 test cases were conducted. In the case of casting all soils at a breath into the water channel, 100 test cases were conducted. The all test results were totally analyzed by the conventional method, with visible judgement by video pictures. Then several important basic problems were found in estimating the volume and particle distributions by the conventional method, which was not found in the past similar studies. It was because the past studies did not consider the types of collisions between sediment particle and pipe. Based on these experiments, the authors have firstly implemented this idea into the old formula to estimate the amount of sediment transport. In the formula, two factors of 1) the rate of sensing in a single collision and 2) the rate of collided particles to a cast all soil particles were concretely considered. The parameters of these factors could be determined from the experimental results and it was found that the obtained formula could estimate grain size distribution. In this paper, they explain the prototype formula to estimate a set of volume and distribution of sediment transport. Another finding in this study is to propose a single collision as a river index to recognize its characteristics of sediment transport. This result could characterize the risk ranking of sediment transport in the rivers and mudflow in the mountainous rivers. Furthermore, in this paper the authors explain how the preciseness of the pipe geophone to sense the smaller sediment particles shall be improved, which has never been able to be sensed.

  20. An information-theoretic approach to the gravitational-wave burst detection problem

    NASA Astrophysics Data System (ADS)

    Katsavounidis, E.; Lynch, R.; Vitale, S.; Essick, R.; Robinet, F.

    2016-03-01

    The advanced era of gravitational-wave astronomy, with data collected in part by the LIGO gravitational-wave interferometers, has begun as of fall 2015. One potential type of detectable gravitational waves is short-duration gravitational-wave bursts, whose waveforms can be difficult to predict. We present the framework for a new detection algorithm - called oLIB - that can be used in relatively low-latency to turn calibrated strain data into a detection significance statement. This pipeline consists of 1) a sine-Gaussian matched-filter trigger generator based on the Q-transform - known as Omicron -, 2) incoherent down-selection of these triggers to the most signal-like set, and 3) a fully coherent analysis of this signal-like set using the Markov chain Monte Carlo (MCMC) Bayesian evidence calculator LALInferenceBurst (LIB). We optimally extract this information by using a likelihood-ratio test (LRT) to map these search statistics into a significance statement. Using representative archival LIGO data, we show that the algorithm can detect gravitational-wave burst events of realistic strength in realistic instrumental noise with good detection efficiencies across different burst waveform morphologies. With support from the National Science Foundation under Grant PHY-0757058.

  1. Self-Organized Criticality and Phase Problem in Magnetoaocustic Emission Burst in Ferromagnets

    NASA Technical Reports Server (NTRS)

    Namkung, M.; Fulton, J. P.; Wincheski, B.

    1993-01-01

    Two types of ferromagnets, pure iron and steel with varying geometry and microstructural properties, were prepared for the present study of magnetoacoustic emission (MAE). The purpose was to separate the effects of structural property variations from changes caused by differences in the sample geometry. The position and shape of the leading MAE sub-burst and its variation among the samples are explained by magnetic anisotropy and the results of numerical simulations which utilized the concept of self-organized criticality (SOC). The amplitude and duration of the second sub-burst, which previously was thought to occur as a result of a complicated interaction between non-180 deg domain walls and lattice defects, can easily be explained by the results of our simulation.

  2. Calculation of sample problems related to two-phase flow blowdown transients in pressure relief piping of a PWR pressurizer

    SciTech Connect

    Shin, Y.W.; Wiedermann, A.H.

    1984-02-01

    A method was published, based on the integral method of characteristics, by which the junction and boundary conditions needed in computation of a flow in a piping network can be accurately formulated. The method for the junction and boundary conditions formulation together with the two-step Lax-Wendroff scheme are used in a computer program; the program in turn, is used here in calculating sample problems related to the blowdown transient of a two-phase flow in the piping network downstream of a PWR pressurizer. Independent, nearly exact analytical solutions also are obtained for the sample problems. Comparison of the results obtained by the hybrid numerical technique with the analytical solutions showed generally good agreement. The good numerical accuracy shown by the results of our scheme suggest that the hybrid numerical technique is suitable for both benchmark and design calculations of PWR pressurizer blowdown transients.

  3. Pipe Flow Simulation Software: A Team Approach to Solve an Engineering Education Problem.

    ERIC Educational Resources Information Center

    Engel, Renata S.; And Others

    1996-01-01

    A computer simulation program for use in the study of fluid mechanics is described. The package is an interactive tool to explore the fluid flow characteristics of a pipe system by manipulating the physical construction of the system. The motivation, software design requirements, and specific details on how its objectives were met are presented.…

  4. Dark matter-induced collapse of neutron stars: a possible link between fast radio bursts and the missing pulsar problem

    NASA Astrophysics Data System (ADS)

    Fuller, Jim; Ott, Christian D.

    2015-06-01

    Fast radio bursts (FRBs) are an emerging class of short and bright radio transients whose sources remain enigmatic. Within the Galactic Centre, the non-detection of pulsars within the inner ˜10 pc has created a missing pulsar problem that has intensified with time. With all reserve, we advance the notion that the two problems could be linked by a common solution: the collapse of neutron stars (NS) due to capture and sedimentation of dark matter (DM) within their cores. Bramante & Linden showed that certain DM properties allow for rapid NS collapse within the high DM density environments near galactic centres while permitting NS survival elsewhere. Each DM-induced collapse could generate an FRB as the NS magnetosphere is suddenly expelled. This scenario could explain several features of FRBs: their short time scales, large energies, locally produced scattering tails, and high event rates. We predict that FRBs are localized to galactic centres, and that our own galactic centre harbours a large population of NS-mass (M ˜ 1.4 M⊙) black holes. The DM-induced collapse scenario is intrinsically unlikely because it can only occur in a small region of allowable DM parameter space. However, if observed to occur, it would place tight constraints on DM properties.

  5. 46 CFR 95.15-15 - Piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Piping. 95.15-15 Section 95.15-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS FIRE PROTECTION EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 95.15-15 Piping. (a) The piping, valves, and fittings shall have a bursting pressure of not...

  6. Magnetar Bursts

    NASA Technical Reports Server (NTRS)

    Kouveliotou, Chryssa

    2014-01-01

    The Fermi/Gamma-ray Burst Monitor (GBM) was launched in June 2008. During the last five years the instrument has observed several hundreds of bursts from 8 confirmed magnetars and 19 events from unconfirmed sources. I will discuss the results of the GBM magnetar burst catalog, expand on the different properties of their diverse source population, and compare these results with the bursting activity of past sources. I will then conclude with thoughts of how these properties fit the magnetar theoretical models.

  7. Piping Connector

    NASA Technical Reports Server (NTRS)

    1993-01-01

    A complex of high pressure piping at Stennis Space Center carries rocket propellants and other fluids/gases through the Center's Component Test Facility. Conventional clamped connectors tend to leak when propellant lines are chilled to extremely low temperatures. Reflange, Inc. customized an existing piping connector to include a secondary seal more tolerant of severe thermal gradients for Stennis. The T-Con connector solved the problem, and the company is now marketing a commercial version that permits testing, monitoring or collecting any emissions that may escape the primary seal during severe thermal transition.

  8. Investigation of Freeze and Thaw Cycles of a Gas-Charged Heat Pipe

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Ottenstein, Laura; Krimchansky, Alexander

    2012-01-01

    The traditional constant conductance heat pipes (CCHPs) currently used on most spacecraft run the risk of bursting the pipe when the working fluid is frozen and later thawed. One method to avoid pipe bursting is to use a gas-charged heat pipe (GCHP) that can sustain repeated freeze/thaw cycles. The construction of the GCHP is similar to that of the traditional CCHP except that a small amount of non-condensable gas (NCG) is introduced and a small length is added to the CCHP condenser to serve as the NCG reservoir. During the normal operation, the NCG is mostly confined to the reservoir, and the GCHP functions as a passive variable conductance heat pipe (VCHP). When the liquid begins to freeze in the condenser section, the NCG will expand to fill the central core of the heat pipe, and ice will be formed only in the grooves located on the inner surface of the heat pipe in a controlled fashion. The ice will not bridge the diameter of the heat pipe, thus avoiding the risk of pipe bursting during freeze/thaw cycles. A GCHP using ammonia as the working fluid was fabricated and then tested inside a thermal vacuum chamber. The GCHP demonstrated a heat transport capability of more than 200W at 298K as designed. Twenty-seven freeze/thaw cycles were conducted under various conditions where the evaporator temperature ranged from 163K to 253K and the condenser/reservoir temperatures ranged from 123K to 173K. In all tests, the GCHP restarted without any problem with heat loads between 10W and 100W. No performance degradation was noticed after 27 freeze/thaw cycles. The ability of the GCHP to sustain repeated freeze/thaw cycles was thus successfully demonstrated.

  9. 46 CFR 108.447 - Piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.447 Piping. (a) Each pipe, valve, and fitting in a CO2 system must have a bursting pressure of at least 420 kilograms per...

  10. Heat pipe investigations

    NASA Technical Reports Server (NTRS)

    Marshburn, J. P.

    1972-01-01

    The OAO-C spacecraft has three circular heat pipes, each of a different internal design, located in the space between the spacecraft structural tube and the experiment tube, which are designed to isothermalize the structure. Two of the pipes are used to transport high heat loads, and the third is for low heat loads. The test problems deal with the charging of the pipes, modifications, the mobile tilt table, the position indicator, and the heat input mechanisms. The final results showed that the techniques used were adequate for thermal-vacuum testing of heat pipes.

  11. Miniature Heat Pipes

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Small Business Innovation Research contracts from Goddard Space Flight Center to Thermacore Inc. have fostered the company work on devices tagged "heat pipes" for space application. To control the extreme temperature ranges in space, heat pipes are important to spacecraft. The problem was to maintain an 8-watt central processing unit (CPU) at less than 90 C in a notebook computer using no power, with very little space available and without using forced convection. Thermacore's answer was in the design of a powder metal wick that transfers CPU heat from a tightly confined spot to an area near available air flow. The heat pipe technology permits a notebook computer to be operated in any position without loss of performance. Miniature heat pipe technology has successfully been applied, such as in Pentium Processor notebook computers. The company expects its heat pipes to accommodate desktop computers as well. Cellular phones, camcorders, and other hand-held electronics are forsible applications for heat pipes.

  12. An investigation of the origin of Rock City and cause of piping problems at Mountain Lake, Giles County, Virginia

    NASA Astrophysics Data System (ADS)

    Atallah, Nidal Walid

    Mountain Lake is one of only two natural lakes in the state of Virginia. The lake's origin has been attributed to either a natural solution-collapse basin, or to a landslide damming the valley of northwesterly flowing Pond Drain, or to a NW-SE trending fracture lineation. The lake is located within the breached northwest limb of a gently plunging anticline, a part of the larger Valley and Ridge physiographic province. In recent years, the lake drained almost completely, exposing the lake bottom and revealing the presence of four sinkhole-like depressions, containing piping holes at their sides and bottoms, at the northeastern and northwestern margins of the lake. This study focuses on the most likely origin of large sandstone blocks present at the northern end of the lake in an area locally referred to as "Rock City", including mapping of the block locations and analyzing the mode and extent of displacement that they have undergone. An additional objective is to investigate the piping potential of the lake-bottom sediment and its role in seepage out of the lake basin causing lake-level fluctuations. Mapping of Rock City was conducted by taking GPS readings at the corners of the rock blocks and using ArcMap Software. Investigations of the displacement mode of the rock blocks was done by comparing the measured orientations of principal discontinuity sets, forming the rock-block boundaries, with discontinuity orientations of undisturbed outcrops within the headscarp, using stereonet analysis. Grain size analysis, Atterberg limits, and a compaction-mold permeameter test were used to evaluate lake sediment's susceptibility to piping. Field observations and discontinuity data analysis indicate that Rock City is a landslide that dammed the valley of Pond Drain, consequently forming the lake. The primary mode of slope movement involves lateral spreading that is associated with extension occurring along discontinuities. The Tuscarora Sandstone rock blocks comprising Rock

  13. Pipe support

    DOEpatents

    Pollono, Louis P.

    1979-01-01

    A pipe support for high temperature, thin-walled piping runs such as those used in nuclear systems. A section of the pipe to be supported is encircled by a tubular inner member comprised of two walls with an annular space therebetween. Compacted load-bearing thermal insulation is encapsulated within the annular space, and the inner member is clamped to the pipe by a constant clamping force split-ring clamp. The clamp may be connected to pipe hangers which provide desired support for the pipe.

  14. A study of circumferentially-heated and block-heated heat pipes. I - Experimental analysis and generalized analytical prediction of capillary limits. II - Three-dimensional numerical modeling as a conjugate problem

    NASA Technical Reports Server (NTRS)

    Schmalhofer, Joseph; Faghri, Amir

    1993-01-01

    The wall and centerline vapor temperatures and heat output are determined experimentally for a low-temperature copper-water heat pipe under uniform circumferential heating and block heating. The time required to reach a vapor temperature of 60 C from an initial ambient temperature of 21 C is determined for both modes of heating. The experimental capillary limit of the heat pipe is compared to the generalized capillary limits for block-heated pipes over a range of vapor temperatures. A three-dimensional numerical model is then developed for determining the temperature, pressure, and velocity distributions in the entire domain of a circumferentially heated and a block-heated pipe. The problem is formulated as a conjugate problem, without the assumption of a uniform vapor temperature. The predictions of the model are found to be in good agreement with the experimental data.

  15. Pipe Dreams.

    ERIC Educational Resources Information Center

    Milshtein, Amy

    2002-01-01

    Discusses the importance of attention to plumbing in college facilities, offering examples from various campuses. Addresses preventive maintenance, technology, and piping materials, including the debate between cast iron and PVC for drain pipes. (EV)

  16. Gamma-ray burst populations

    NASA Astrophysics Data System (ADS)

    Virgili, Francisco Javier

    Over the last fifty years the field of gamma-ray bursts has shown incredible growth, but the amassing of data has also left observers and theorists alike wondering about some of the basic questions surrounding these phenomena. Additionally, these events show remarkable individuality and extrema, ranging in redshift throughout the observable universe and over ten orders of magnitude in energy. This work focuses on analyzing groups of bursts that are different from the general trend and trying to understand whether these bursts are from different intrinsic populations and if so, what can be said about their progenitors. This is achieved through numerical Monte Carlo simulations and statistical inference in conjunction with current GRB observations. Chapter 1 gives a general introduction of gamma-ray burst theory and observations in a semi-historical context. Chapter 2 provides an introduction to the theory and practical issues surrounding the numerical simulations and statistics. Chapters 3--5 are each dedicated to a specific problem relating to a different type of GRB population: high-luminosity v. low-luminosity bursts, constraints from high-redshift bursts, and Type I v. Type II bursts. Chapter 6 follows with concluding remarks.

  17. Heat Pipes

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Phoenix Refrigeration Systems, Inc.'s heat pipe addition to the Phoenix 2000, a supermarket rooftop refrigeration/air conditioning system, resulted from the company's participation in a field test of heat pipes. Originally developed by NASA to control temperatures in space electronic systems, the heat pipe is a simple, effective, heat transfer system. It has been used successfully in candy storage facilities where it has provided significant energy savings. Additional data is expected to fully quantify the impact of the heat pipes on supermarket air conditioning systems.

  18. Sample problem calculations related to two-phase flow transients in a PWR relief-piping network

    SciTech Connect

    Shin, Y.W.; Wiedermann, A.H.

    1981-03-01

    Two sample problems related with the fast transients of water/steam flow in the relief line of a PWR pressurizer were calculated with a network-flow analysis computer code STAC (System Transient-Flow Analysis Code). The sample problems were supplied by EPRI and are designed to test computer codes or computational methods to determine whether they have the basic capability to handle the important flow features present in a typical relief line of a PWR pressurizer. It was found necessary to implement into the STAC code a number of additional boundary conditions in order to calculate the sample problems. This includes the dynamics of the fluid interface that is treated as a moving boundary. This report describes the methodologies adopted for handling the newly implemented boundary conditions and the computational results of the two sample problems. In order to demonstrate the accuracies achieved in the STAC code results, analytical solutions are also obtained and used as a basis for comparison.

  19. Pipe connector

    DOEpatents

    Sullivan, Thomas E.; Pardini, John A.

    1978-01-01

    A safety test facility for testing sodium-cooled nuclear reactor components includes a reactor vessel and a heat exchanger submerged in sodium in the tank. The reactor vessel and heat exchanger are connected by an expansion/deflection pipe coupling comprising a pair of coaxially and slidably engaged tubular elements having radially enlarged opposed end portions of which at least a part is of spherical contour adapted to engage conical sockets in the ends of pipes leading out of the reactor vessel and in to the heat exchanger. A spring surrounding the pipe coupling urges the end portions apart and into engagement with the spherical sockets. Since the pipe coupling is submerged in liquid a limited amount of leakage of sodium from the pipe can be tolerated.

  20. Heat pipe dynamic behavior

    NASA Technical Reports Server (NTRS)

    Issacci, F.; Roche, G. L.; Klein, D. B.; Catton, I.

    1988-01-01

    The vapor flow in a heat pipe was mathematically modeled and the equations governing the transient behavior of the core were solved numerically. The modeled vapor flow is transient, axisymmetric (or two-dimensional) compressible viscous flow in a closed chamber. The two methods of solution are described. The more promising method failed (a mixed Galerkin finite difference method) whereas a more common finite difference method was successful. Preliminary results are presented showing that multi-dimensional flows need to be treated. A model of the liquid phase of a high temperature heat pipe was developed. The model is intended to be coupled to a vapor phase model for the complete solution of the heat pipe problem. The mathematical equations are formulated consistent with physical processes while allowing a computationally efficient solution. The model simulates time dependent characteristics of concern to the liquid phase including input phase change, output heat fluxes, liquid temperatures, container temperatures, liquid velocities, and liquid pressure. Preliminary results were obtained for two heat pipe startup cases. The heat pipe studied used lithium as the working fluid and an annular wick configuration. Recommendations for implementation based on the results obtained are presented. Experimental studies were initiated using a rectangular heat pipe. Both twin beam laser holography and laser Doppler anemometry were investigated. Preliminary experiments were completed and results are reported.

  1. Optical search for gamma-ray bursts

    NASA Astrophysics Data System (ADS)

    Hudec, R.; Ceplecha, Z.; Ehrlich, J.; Borovicka, J.; Hurley, K.; Ateia, J.-L.; Barat, C.; Niel, M.; Vedrenne, G.; Estulin, I. V.

    Preliminary results from an optical search for light pulses associated with gamma-ray bursts by means of the Czechoslovak Fireball Network plate collection at the Ondřejov Observatory are given. Optical monitoring represents more than 7700 hours, but no real optical counterpart was found. Problems associated with the optical search for gamma-ray bursts are discussed.

  2. Silicon Heat Pipe Array

    NASA Technical Reports Server (NTRS)

    Yee, Karl Y.; Ganapathi, Gani B.; Sunada, Eric T.; Bae, Youngsam; Miller, Jennifer R.; Beinsford, Daniel F.

    2013-01-01

    Improved methods of heat dissipation are required for modern, high-power density electronic systems. As increased functionality is progressively compacted into decreasing volumes, this need will be exacerbated. High-performance chip power is predicted to increase monotonically and rapidly with time. Systems utilizing these chips are currently reliant upon decades of old cooling technology. Heat pipes offer a solution to this problem. Heat pipes are passive, self-contained, two-phase heat dissipation devices. Heat conducted into the device through a wick structure converts the working fluid into a vapor, which then releases the heat via condensation after being transported away from the heat source. Heat pipes have high thermal conductivities, are inexpensive, and have been utilized in previous space missions. However, the cylindrical geometry of commercial heat pipes is a poor fit to the planar geometries of microelectronic assemblies, the copper that commercial heat pipes are typically constructed of is a poor CTE (coefficient of thermal expansion) match to the semiconductor die utilized in these assemblies, and the functionality and reliability of heat pipes in general is strongly dependent on the orientation of the assembly with respect to the gravity vector. What is needed is a planar, semiconductor-based heat pipe array that can be used for cooling of generic MCM (multichip module) assemblies that can also function in all orientations. Such a structure would not only have applications in the cooling of space electronics, but would have commercial applications as well (e.g. cooling of microprocessors and high-power laser diodes). This technology is an improvement over existing heat pipe designs due to the finer porosity of the wick, which enhances capillary pumping pressure, resulting in greater effective thermal conductivity and performance in any orientation with respect to the gravity vector. In addition, it is constructed of silicon, and thus is better

  3. Burst suppression probability algorithms: state-space methods for tracking EEG burst suppression

    NASA Astrophysics Data System (ADS)

    Chemali, Jessica; Ching, ShiNung; Purdon, Patrick L.; Solt, Ken; Brown, Emery N.

    2013-10-01

    Objective. Burst suppression is an electroencephalogram pattern in which bursts of electrical activity alternate with an isoelectric state. This pattern is commonly seen in states of severely reduced brain activity such as profound general anesthesia, anoxic brain injuries, hypothermia and certain developmental disorders. Devising accurate, reliable ways to quantify burst suppression is an important clinical and research problem. Although thresholding and segmentation algorithms readily identify burst suppression periods, analysis algorithms require long intervals of data to characterize burst suppression at a given time and provide no framework for statistical inference. Approach. We introduce the concept of the burst suppression probability (BSP) to define the brain's instantaneous propensity of being in the suppressed state. To conduct dynamic analyses of burst suppression we propose a state-space model in which the observation process is a binomial model and the state equation is a Gaussian random walk. We estimate the model using an approximate expectation maximization algorithm and illustrate its application in the analysis of rodent burst suppression recordings under general anesthesia and a patient during induction of controlled hypothermia. Main result. The BSP algorithms track burst suppression on a second-to-second time scale, and make possible formal statistical comparisons of burst suppression at different times. Significance. The state-space approach suggests a principled and informative way to analyze burst suppression that can be used to monitor, and eventually to control, the brain states of patients in the operating room and in the intensive care unit.

  4. Piping Analysis

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Burns & McDonnell provide architectural and engineering services in planning, design and construction of a wide range of projects all over the world. In design analysis, company regularly uses COSMIC computer programs. In computer testing piping design of a power plant, company uses Pipe Flexibility Analysis Program (MEL-21) to analyze stresses due to weight, temperature, and pressure found in proposed piping systems. Individual flow rates are put into the computer, then computer calculates the pressure drop existing across each component; if needed, design corrections or adjustments can be made and rechecked.

  5. Piping Flexibility

    NASA Technical Reports Server (NTRS)

    1978-01-01

    A NASA computer program aids Hudson Engineering Corporation, Houston, Texas, in the design and construction of huge petrochemical processing plants like the one shown, which is located at Ju'aymah, Saudi Arabia. The pipes handling the flow of chemicals are subject to a variety of stresses, such as weight and variations in pressure and temperature. Hudson Engineering uses a COSMIC piping flexibility analysis computer program to analyze stresses and unsure the necessary strength and flexibility of the pipes. This program helps the company realize substantial savings in reduced engineering time.

  6. Light pipes for LED measurements

    NASA Technical Reports Server (NTRS)

    Floyd, S. R.; Thomas, E. F., Jr.

    1976-01-01

    Light pipe directly couples LED optical output to single detector. Small area detector measures total optical output of diode. Technique eliminates thermal measurement problems and channels optical output to remote detector.

  7. Heat Pipe Integrated Microsystems

    SciTech Connect

    Gass, K.; Robertson, P.J.; Shul, R.; Tigges, C.

    1999-03-30

    The trend in commercial electronics packaging to deliver ever smaller component packaging has enabled the development of new highly integrated modules meeting the demands of the next generation nano satellites. At under ten kilograms, these nano satellites will require both a greater density electronics and a melding of satellite structure and function. Better techniques must be developed to remove the subsequent heat generated by the active components required to-meet future computing requirements. Integration of commercially available electronics must be achieved without the increased costs normally associated with current generation multi chip modules. In this paper we present a method of component integration that uses silicon heat pipe technology and advanced flexible laminate circuit board technology to achieve thermal control and satellite structure. The' electronics/heat pipe stack then becomes an integral component of the spacecraft structure. Thermal management on satellites has always been a problem. The shrinking size of electronics and voltage requirements and the accompanying reduction in power dissipation has helped the situation somewhat. Nevertheless, the demands for increased onboard processing power have resulted in an ever increasing power density within the satellite body. With the introduction of nano satellites, small satellites under ten kilograms and under 1000 cubic inches, the area available on which to place hot components for proper heat dissipation has dwindled dramatically. The resulting satellite has become nearly a solid mass of electronics with nowhere to dissipate heat to space. The silicon heat pipe is attached to an aluminum frame using a thermally conductive epoxy or solder preform. The frame serves three purposes. First, the aluminum frame provides a heat conduction path from the edge of the heat pipe to radiators on the surface of the satellite. Secondly, it serves as an attachment point for extended structures attached to

  8. Large-bore pipe decontamination

    SciTech Connect

    Ebadian, M.A.

    1998-01-01

    The decontamination and decommissioning (D and D) of 1200 buildings within the US Department of Energy-Office of Environmental Management (DOE-EM) Complex will require the disposition of miles of pipe. The disposition of large-bore pipe, in particular, presents difficulties in the area of decontamination and characterization. The pipe is potentially contaminated internally as well as externally. This situation requires a system capable of decontaminating and characterizing both the inside and outside of the pipe. Current decontamination and characterization systems are not designed for application to this geometry, making the direct disposal of piping systems necessary in many cases. The pipe often creates voids in the disposal cell, which requires the pipe to be cut in half or filled with a grout material. These methods are labor intensive and costly to perform on large volumes of pipe. Direct disposal does not take advantage of recycling, which could provide monetary dividends. To facilitate the decontamination and characterization of large-bore piping and thereby reduce the volume of piping required for disposal, a detailed analysis will be conducted to document the pipe remediation problem set; determine potential technologies to solve this remediation problem set; design and laboratory test potential decontamination and characterization technologies; fabricate a prototype system; provide a cost-benefit analysis of the proposed system; and transfer the technology to industry. This report summarizes the activities performed during fiscal year 1997 and describes the planned activities for fiscal year 1998. Accomplishments for FY97 include the development of the applicable and relevant and appropriate regulations, the screening of decontamination and characterization technologies, and the selection and initial design of the decontamination system.

  9. Heat Pipes

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Bobs Candies, Inc. produces some 24 million pounds of candy a year, much of it 'Christmas candy.' To meet Christmas demand, it must produce year-round. Thousands of cases of candy must be stored a good part of the year in two huge warehouses. The candy is very sensitive to temperature. The warehouses must be maintained at temperatures of 78-80 degrees Fahrenheit with relative humidities of 38- 42 percent. Such precise climate control of enormous buildings can be very expensive. In 1985, energy costs for the single warehouse ran to more than $57,000 for the year. NASA and the Florida Solar Energy Center (FSEC) were adapting heat pipe technology to control humidity in building environments. The heat pipes handle the jobs of precooling and reheating without using energy. The company contacted a FSEC systems engineer and from that contact eventually emerged a cooperative test project to install a heat pipe system at Bobs' warehouses, operate it for a period of time to determine accurately the cost benefits, and gather data applicable to development of future heat pipe systems. Installation was completed in mid-1987 and data collection is still in progress. In 1989, total energy cost for two warehouses, with the heat pipes complementing the air conditioning system was $28,706, and that figures out to a cost reduction.

  10. Pipe gripper

    DOEpatents

    Moyers, S.M.

    1975-12-16

    A device for gripping the exterior surface of a pipe or rod is described which has a plurality of wedges, each having a concave face which engages the outer surface of the pipe and each having a smooth face opposing the concave face. The wedges are seated on and their grooved concave faces are maintained in circular alignment by tapered axial segments of an opening extending through a wedge-seating member. The wedges are allowed to slide across the tapered axial segments so that such a sliding movement acts to vary the diameter of the circular alignment.

  11. Heat Pipes

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Heat Pipes were originally developed by NASA and the Los Alamos Scientific Laboratory during the 1960s to dissipate excessive heat build- up in critical areas of spacecraft and maintain even temperatures of satellites. Heat pipes are tubular devices where a working fluid alternately evaporates and condenses, transferring heat from one region of the tube to another. KONA Corporation refined and applied the same technology to solve complex heating requirements of hot runner systems in injection molds. KONA Hot Runner Systems are used throughout the plastics industry for products ranging in size from tiny medical devices to large single cavity automobile bumpers and instrument panels.

  12. Heat Pipes For Alyeska

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The heat pipes job is to keep the arctic ground frozen. The permafrost soil alternately freezes and thaws with seasonal temperature changes causing surface dislocations and problems for the builders. In winter, a phenomenon called frost-heaving uplifts the soil. It is something like the creation of highway potholes by the freezing of rainwater below the roadbed, but frost-heaving exerts a far greater force. Thawing of the frost in the summer causes the soil to settle unevenly. Therefore it is necessary to keep the soil in a continually frozen state so the pipeline won't rupture. To solve this problem, McDonnell Douglas Corp. applied heat pipe principles in the design of the vertical supports that hold up the pipeline.

  13. A data channel scheduling algorithm based on burst migration for optical burst switching networks

    NASA Astrophysics Data System (ADS)

    Zhang, Min; Yang, Xiaolong; Liu, Hui

    2004-05-01

    Currently optical burst switching (OBS) has been regarded as the most promising backbone networking technology for the next-generation Internet. In the OBS network, the data channel scheduling is one of key problems. Bandwidth efficiency and QoS support are its two concern focuses. However, the existing algorithms pay more attention to bandwidth efficiency. In this paper, we develop an efficient data channel scheduling algorithm, called BM-VF-SBD. It effectively integrates several mechanisms (i.e., void filling, burst migration and selective burst discard) to reduce the bandwidth fragment and support QoS. Its basic idea is in that a new burst is scheduled by migrating some bursts to other channels if none of voids in any channels can accommodate it; otherwise repeating the above processes after selectively dropping some bursts. Meanwhile under an effective data structure, such as the balanced binary search tree, its computational complexity will be o[(2w+1)log w] at most, and be close to LAUC-VF and ODBR. In the proposed algorithm, burst migration plays a key role in the improvement of bandwidth efficiency while selective burst discard has great effects on the two sides. The simulation results show that it performs much better than LAUC-VF and ODBR in burst loss probability (overall or individual) and bandwidth fragment ratio.

  14. Heat Pipe Systems

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Solar Fundamentals, Inc.'s hot water system employs space-derived heat pipe technology. It is used by a meat packing plant to heat water for cleaning processing machinery. Unit is complete system with water heater, hot water storage, electrical controls and auxiliary components. Other than fans and a circulating pump, there are no moving parts. System's unique design eliminates problems of balancing, leaking, corroding, and freezing.

  15. Electrohydrodynamic heat pipe research

    NASA Technical Reports Server (NTRS)

    Jones, T. B.; Perry, M. P.

    1973-01-01

    Experimental and theoretical applications to electrohydrodynamic heat pipe (EHDHP) research are presented. Two problems in the research which are discussed are the prediction of the effective thermal conductance of an EHDHP with threaded grooves for fluid distribution to the evaporator of an EHDHP. Hydrodynamic equations are included along with a discussion of boundary conditions and burn-out conditions. A discussion of the theoretical and experimental results is presented.

  16. Burst-by-burst laser frequency monitor

    NASA Technical Reports Server (NTRS)

    Esproles, Carlos (Inventor)

    1994-01-01

    The invention is a system for real-time frequency monitoring and display of an RF burst where the burst frequency is analyzed and displayed on a burst-by-burst basis in order to allow for frequency control. Although the invention was made for monitoring the laser frequency of a LIDAR system, it has other applications where realtime monitoring is required. The novelty of the invention resides in the use of a counter that is reset at the beginning of each unit time of monitoring and then gated for a unit of time. The invention also has an LED bar graph for displaying the measure of frequency at the end of each unit time in either a bar length mode or a moving dot mode. In the latter mode, the operator makes necessary adjustments to maintain the dot at the center of the bar graph.

  17. How long does a burst burst?

    SciTech Connect

    Zhang, Bin-Bin; Connaughton, Valerie; Briggs, Michael S.; Zhang, Bing; Murase, Kohta

    2014-05-20

    Several gamma-ray bursts (GRBs) last much longer (∼hours) in γ-rays than typical long GRBs (∼minutes), and it has recently been proposed that these 'ultra-long GRBs' may form a distinct population, probably with a different (e.g., blue supergiant) progenitor than typical GRBs. However, Swift observations suggest that many GRBs have extended central engine activities manifested as flares and internal plateaus in X-rays. We perform a comprehensive study on a large sample of Swift GRBs with X-Ray Telescope observations to investigate GRB central engine activity duration and to determine whether ultra-long GRBs are unusual events. We define burst duration t {sub burst} based on both γ-ray and X-ray light curves rather than using γ-ray observations alone. We find that t {sub burst} can be reliably measured in 343 GRBs. Within this 'good' sample, 21.9% GRBs have t {sub burst} ≳ 10{sup 3} s and 11.5% GRBs have t {sub burst} ≳ 10{sup 4} s. There is an apparent bimodal distribution of t {sub burst} in this sample. However, when we consider an 'undetermined' sample (304 GRBs) with t {sub burst} possibly falling in the gap between GRB duration T {sub 90} and the first X-ray observational time, as well as a selection effect against t {sub burst} falling into the first Swift orbital 'dead zone' due to observation constraints, the intrinsic underlying t {sub burst} distribution is consistent with being a single component distribution. We found that the existing evidence for a separate ultra-long GRB population is inconclusive, and further multi-wavelength observations are needed to draw a firmer conclusion. We also discuss the theoretical implications of our results. In particular, the central engine activity duration of GRBs is generally much longer than the γ-ray T {sub 90} duration and it does not even correlate with T {sub 90}. It would be premature to make a direct connection between T {sub 90} and the size of the progenitor star.

  18. NASTRAN analysis of an air storage piping system

    NASA Technical Reports Server (NTRS)

    Young, C. P., Jr.; Gerringer, A. H.; Faison, R. W.

    1973-01-01

    The application of NASTRAN to a complex piping design evaluation problem is summarized. Emphasis is placed on structural modeling aspects, problems encountered in modeling and analyzing curved pipe sections, principal results, and relative merits of using NASTRAN as a pipe analysis and design tool. In addition, the piping and manifolding system was analyzed with SNAP (Structural Network Analysis Program). The parallel SNAP study provides a basis for limited comparisons between NASTRAN and SNAP as to solution agreement and computer execution time and costs.

  19. The GLAST Burst Monitor

    NASA Technical Reports Server (NTRS)

    Meegan, Charles; Bhat, Narayana; Connaughton, Valerie; Briggs, Michael; Diehl, Roland; Fishman, Gerald; Greiner, Jochen; Kippen, R. Marc; vonKienlin, Andreas; Kouveliotou, Chryssa; Lichti, Giselher; Paciesas, William; Preece, Robert; Steinle, Helmut; Wilson-Hodge, Colleen

    2007-01-01

    The GLAST Burst Monitor (GBM) comprises an array of NaI and BGO scintillation detectors designed to enhance the scientific return from GLAST in the study of gamma-ray bursts (GRBs). By observing in the 10 keV to 30 MeV energy range, GBM extends the spectral coverage of GRBs more than 3 decades below the LAT energy threshold. GBM computes burst locations on-board, allowing repointing of the GLAST Observatory to place strong bursts within the LAT field-of-view to observe delayed high-energy emission.

  20. The GLAST Burst Monitor

    SciTech Connect

    Meegan, Charles; Fishman, Gerald; Kouveliotou, Chryssa; Wilson-Hodge, Colleen; Bhat, Narayana; Connaughton, Valerie; Briggs, Michael; Paciesas, William; Preece, Robert; Diehl, Roland; Greiner, Jochen; Kienlin, Andreas von; Lichti, Giselher; Steinle, Helmut; Kippen, R. Marc

    2007-07-12

    The GLAST Burst Monitor (GBM) comprises an array of NaI and BGO scintillation detectors designed to enhance the scientific return from GLAST in the study of gamma-ray bursts (GRBs). By observing in the 10 keV to 30 MeV energy range, GBM extends the spectral coverage of GRBs more than 3 decades below the LAT energy threshold. GBM computes burst locations on-board, allowing repointing of the GLAST Observatory to place strong bursts within the LAT field-of-view to observe delayed high-energy emission.

  1. Heat pipe technology

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A bibliography of heat pipe technology to provide a summary of research projects conducted on heat pipes is presented. The subjects duscussed are: (1) heat pipe applications, (2) heat pipe theory, (3) design and fabrication, (4) testing and operation, (5) subject and author index, and (6) heat pipe related patents.

  2. PBF Reactor Building (PER620). Piping in basement fills space. Secondary ...

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

    PBF Reactor Building (PER-620). Piping in basement fills space. Secondary coolant flowed through carbon steel pipe; primary coolant, through stainless steel. Photographer: Larry Page. Date: April 30, 1970. INEEL negative no. 70-2080 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

  3. Gamma Ray Bursts - Observations

    NASA Technical Reports Server (NTRS)

    Gehrels, N.; Cannizzo, J. K.

    2010-01-01

    We are in an exciting period of discovery for gamma-ray bursts. The Swift observatory is detecting 100 bursts per year, providing arcsecond localizations and sensitive observations of the prompt and afterglow emission. The Fermi observatory is observing 250 bursts per year with its medium-energy GRB instrument and about 10 bursts per year with its high-energy LAT instrument. In addition, rapid-response telescopes on the ground are providing new capabilities to study optical emission during the prompt phase and spectral signatures of the host galaxies. The combined data set is enabling great advances in our understanding of GRBs including afterglow physics, short burst origin, and high energy emission.

  4. Sawtooth bursts: observations and model

    NASA Astrophysics Data System (ADS)

    Karlický, M.; Bárta, M.; Klassen, A.; Aurass, H.; Mann, G.

    2002-12-01

    An example of the sawtooth burst observed during the November 3, 1997 flare is shown. Basic parameters of the sawtooth bursts are summarized and compared with those of fibers, fiber chains, zebras, EEL bursts and lace bursts. The sawtooth bursts are found to be most similar to the lace bursts, therefore the lace bursts model is proposed also for them. Then using this model the dynamic spectrum with the sawtooth burst is modelled. The model considers accelerated electrons with an unstable distribution function on the double resonance frequency and quasi-periodic variations of the electron plasma density and/or magnetic field in the radio source.

  5. The feasibility of electrohydrodynamic heat pipes

    NASA Technical Reports Server (NTRS)

    Jones, T. B.

    1971-01-01

    The effect of a nonuniform electrostatic field on insulating dielectric liquids in heat pipes was studied. Topics discussed include the theory of operation, design criteria, and evaluation of optimal design features. It is concluded that the electrodynamic heat pipes offer advantages that must be weighed against the disadvantages in order to arrive at a proper assessment of their value in solving heat transfer problems.

  6. Heat Pipe Precools and Reheats Dehumidified Air

    NASA Technical Reports Server (NTRS)

    Koning, R. C.; Boggs, W. H.; Barnett, U. R.; Dinh, K.

    1986-01-01

    Precooling and reheating by heat pipe reduces operating costs of air-conditioning. Warm air returned from air-conditioned space and cooled air supplied are precooled and reheated, respectively, by each other through a heat pipe. Heat-pipe technology brought to bear on problem of conserving airconditioning energy in hot, humid environments. Any increase in the cost of equipment due to installation of heat-pipe heat exchangers expected to be recovered in energy savings during service period of 2 years or less.

  7. Flow conditions of fresh mortar and concrete in different pipes

    SciTech Connect

    Jacobsen, Stefan; Haugan, Lars; Hammer, Tor Arne; Kalogiannidis, Evangelos

    2009-11-15

    The variation in fresh concrete flow rate over the pipe cross section was investigated on differently coloured and highly flowable concrete mixes flowing through pipes of different materials (rubber, steel, acryl). First, uncoloured (gray) concrete was poured through the pipe and the pipe blocked. Similar but coloured (black) concrete was then poured into the pipe filled with gray concrete, flowing after the gray concrete for a while before being blocked and hardened. The advance of the colouring along the pipe wall (showing boundary flow rate) was observed on the moulded concrete surface appearing after removing the pipe from the hardened concrete. The shapes of the interfaces between uncoloured and coloured concrete (showing variation of flow rate over the pipe cross section) were observed on sawn surfaces of concrete half cylinders cut along the length axes of the concrete-filled pipe. Flow profiles over the pipe cross section were clearly seen with maximum flow rates near the centre of the pipe and low flow rate at the pipe wall (typically rubber pipe with reference concrete without silica fume and/or stabilizers). More plug-shaped profiles, with long slip layers and less variation of flow rate over the cross section, were also seen (typically in smooth acrylic pipes). Flow rate, amount of concrete sticking to the wall after flow and SEM-images of pipe surface roughness were observed, illustrating the problem of testing full scale pumping.

  8. Applications of heat pipes to cool PWBS and hybrid microcircuits

    NASA Technical Reports Server (NTRS)

    Sekhon, K. S.

    1986-01-01

    Some of the advanced thermal management techniques used to reduce operating junction temperature under extreme environmental temperature conditions are discussed. Heat pipes in actual electronic packaging applications, and those under development, are discussed. Performance characteristics of heat pipes are given, and examples are described of how thermal problems in electronic packaging are solved through the use of heat pipes.

  9. On vortex bursting

    NASA Technical Reports Server (NTRS)

    Werle, H.

    1984-01-01

    Vortex bursting is studied by means of visualization. The physical behavior of the phenomenon is emphasized, and its similarity with boundary layer separation or wake bursting becomes apparent. The essential influence of an increasing pressure gradient on the initiation, the position and the type of bursting is clearly confirmed. The evolution of the phenomena as a function of several parameters is analyzed in the case of delta wings, alone or installed on aircraft models, and compared with the results of similar wind tunnel or flight tests.

  10. Ultrasonic pipe assessment

    SciTech Connect

    Thomas, Graham H.; Morrow, Valerie L.; Levie, Harold; Kane, Ronald J.; Brown, Albert E.

    2003-12-23

    An ultrasonic pipe or other structure assessment system includes an ultrasonic transducer positioned proximate the pipe or other structure. A fluid connection between the ultrasonic transducer and the pipe or other structure is produced. The ultrasonic transducer is moved relative to the pipe or other structure.

  11. Shield For Flexible Pipe

    NASA Technical Reports Server (NTRS)

    Ponton, Michael K.; Williford, Clifford B.; Lagen, Nicholas T.

    1995-01-01

    Cylindrical shield designed to fit around flexible pipe to protect nearby workers from injury and equipment from damage if pipe ruptures. Designed as pressure-relief device. Absorbs impact of debris ejected radially from broken flexible pipe. Also redirects flow of pressurized fluid escaping from broken pipe onto flow path allowing for relief of pressure while minimizing potential for harm.

  12. Optimal Codes for the Burst Erasure Channel

    NASA Technical Reports Server (NTRS)

    Hamkins, Jon

    2010-01-01

    Deep space communications over noisy channels lead to certain packets that are not decodable. These packets leave gaps, or bursts of erasures, in the data stream. Burst erasure correcting codes overcome this problem. These are forward erasure correcting codes that allow one to recover the missing gaps of data. Much of the recent work on this topic concentrated on Low-Density Parity-Check (LDPC) codes. These are more complicated to encode and decode than Single Parity Check (SPC) codes or Reed-Solomon (RS) codes, and so far have not been able to achieve the theoretical limit for burst erasure protection. A block interleaved maximum distance separable (MDS) code (e.g., an SPC or RS code) offers near-optimal burst erasure protection, in the sense that no other scheme of equal total transmission length and code rate could improve the guaranteed correctible burst erasure length by more than one symbol. The optimality does not depend on the length of the code, i.e., a short MDS code block interleaved to a given length would perform as well as a longer MDS code interleaved to the same overall length. As a result, this approach offers lower decoding complexity with better burst erasure protection compared to other recent designs for the burst erasure channel (e.g., LDPC codes). A limitation of the design is its lack of robustness to channels that have impairments other than burst erasures (e.g., additive white Gaussian noise), making its application best suited for correcting data erasures in layers above the physical layer. The efficiency of a burst erasure code is the length of its burst erasure correction capability divided by the theoretical upper limit on this length. The inefficiency is one minus the efficiency. The illustration compares the inefficiency of interleaved RS codes to Quasi-Cyclic (QC) LDPC codes, Euclidean Geometry (EG) LDPC codes, extended Irregular Repeat Accumulate (eIRA) codes, array codes, and random LDPC codes previously proposed for burst erasure

  13. Short cracks in piping and piping welds

    SciTech Connect

    Wilkowski, G.M.; Brust, F.; Francini, R.; Ghadiali, N.; Kilinski, T.; Krishnaswamy, P.; Landow, M.; Marschall, C.W.; Rahman, S.; Scott, P. )

    1992-04-01

    This is the second semiannual report of the US Nuclear Regulatory Commission's Short Cracks in Piping and Piping Welds research program. The program began in March 1990 and will extend for 4 years. The intent of this program is to verify and improve fracture analyses for circumferentially cracked large-diameter nuclear piping with crack sizes typically used in leak-before-break analyses or in-service flaw evaluations. Only quasi-static loading rates are evaluated since the NRC's International Piping Integrity Research Group (IPIRG) program is evaluating the effects of seismic loading rates on cracked piping systems. Progress for through-wall-cracked pipe involved (1) conducting a 28-inch diameter stainless steel SAW and 4-inch diameter French TP316 experiments, (2) conducting a matrix of FEM analyses to determine GE/EPRI functions for short TWC pipe, (3) comparison of uncracked pipe maximum moments to various analyses and FEM solutions, (4) development of a J-estimation scheme that includes the strength of both the weld and base metals. Progress for surface-cracked pipe involved (1) conducting two experiments on 6-inch diameter pipe with d/t = 0.5 and {Theta}/{pi} = 0.25 cracks, (2) comparisons of the pipe experiments to Net-Section-Collapse predictions, and (3) modification of the SC.TNP and SC.TKP J-estimation schemes to include external surface cracks.

  14. INTEGRAL burst alert service

    NASA Technical Reports Server (NTRS)

    Pedersen, H.; Jennings, D.; Mereghetti, S.; Teegarden, B.

    1997-01-01

    The detection, accurate positioning, and spectral analysis of cosmic gamma ray bursts is an objective of the International Gamma Ray Astrophysics Laboratory (INTEGRAL) mission. Due to their unpredictable nature, gamma ray bursts can only be observed in serendipity mode. In order to allow and promote multiwavelength follow-up observations of such events, it is desirable to make the information available to the astrophysics community with a minimum delay through the use of Internet. Ideally, the data dissemination should occur within a few seconds of the start of the burst event so that follow up observations can proceed while gamma rays are still being emitted. The technical feasibility of building such a system to disseminate INTEGRAL burst alerts in real time is currently under consideration, the preliminary results of which are presented. It is concluded that such an alert service is technically feasible.

  15. Extragalactic Radio Bursts

    NASA Astrophysics Data System (ADS)

    Bailes, Matthew; Johnston, Simon; Bhat, Ramesh; Burke-Spolaor, Sarah; Barnes, David; van Straten, Willem

    2008-04-01

    We propose a sky monitoring survey that will piggy-back multibeam observations of other scientific programmes; the intent of our search is to intercept and analyse millisecond-duration, single, impulsive bursts from transient events in the extragalactic sky.

  16. Extragalactic Radio Bursts

    NASA Astrophysics Data System (ADS)

    Burke-Spolaor, Sarah; Johnston, Simon; Bailes, Matthew; Bhat, Ramesh; Barnes, David; van Straten, Willem

    2008-10-01

    We propose a sky monitoring survey that will piggy-back multibeam observations of other scientific programmes; the intent of our search is to intercept and analyse millisecond-duration, single, impulsive bursts from transient events in the extragalactic sky.

  17. Organ pipe resonance induced vibration in piping system

    SciTech Connect

    Wang, T.

    1996-12-01

    Acoustic-induced vibration is a fluid-structure interaction phenomenon. The feedback mechanism between the acoustic pressure pulsation and the structure movements determines the excited acoustic modes which, in turn, amplify the structure response when confidence frequency and mode shape matching occurs. The acoustic modes are not determined from the acoustic boundary conditions alone, structure feedback is as responsible for determining the acoustic modes and shaping the resulting forcing functions. Acoustic-induced piping vibration, when excited, does not attenuate much with distance. Pressure pulsation can be transmitted throughout the piping system and its branch connections. It is this property that makes vibration monitoring difficult, because vibration can surface at locations far away from the acoustic source when resonance occurs. For a large piping system with interconnected branches, the monitoring task can be formidable, particularly when there is no indication what the real source is. In organ pipe resonance induced vibration, the initiating acoustic source may be inconspicuous or unavoidable during operation. In these situations, the forcing function approach can offer an optimal tool for vibration assessment. The forcing function approach was used in the evaluation of a standby steam piping vibration problem. Monitoring locations and instrument specifications were determined from the acoustic eigenfunction profiles. Measured data confirmed the presence of coherent vibrations in the large bore piping. The developed forcing function permits design evaluation of the piping system, which leads to remedial actions and enables fatigue life determination, thus providing confidence to system operation. The forcing function approach is shown to be useful in finding potential vibration area and verifying the integrity of weak structure links. Application is to steam lines at BWR plants.

  18. GLAST's GBM Burst Trigger

    NASA Technical Reports Server (NTRS)

    Band, D.; Briggs, M.; Connaughton, V.; Kippen, M.; Preece, R.

    2003-01-01

    The GLAST Burst Monitor (GBM) will detect and localize bursts for the GLAST mission, and provide the spectral and temporal context in the traditional 10 keV to 25 MeV band for the high energy observations by the Large Area Telescope (LAT). The GBM will use traditional rate triggers in up to three energy bands, and on a variety of timescales between 16 ms and 16 s.

  19. GLAST's GBM Burst Trigger

    SciTech Connect

    Band, D.; Kippen, M.

    2004-09-28

    The GLAST Burst Monitor (GBM) will detect and localize bursts for the GLAST mission, and provide the spectral and temporal context in the traditional 10 keV to 25 MeV band for the high energy observations by the Large Area Telescope (LAT). The GBM will use traditional rate triggers in up to three energy bands, and on a variety of timescales between 16 ms and 16 s.

  20. Burst diaphragm sequence valve

    NASA Astrophysics Data System (ADS)

    Wisneskie, Bradley D.; Hyman, Sheldon; Hallum, Charles E.

    1991-11-01

    A burst diaphragm sequence valve which effectively combines the structure of a burst diaphragm with that of an ordinary swing check valve, the pivot of the ordinary swing check valve being replaced by an integral flexural hinge. The sequence valve provides a way to sequentially burn solid propellant hot gas generators which exit into a common gas manifold, thereby enabling gas-powered devices to operate for a longer time than the duration of one gas generator burn.

  1. Parameters for burst detection

    PubMed Central

    Bakkum, Douglas J.; Radivojevic, Milos; Frey, Urs; Franke, Felix; Hierlemann, Andreas; Takahashi, Hirokazu

    2014-01-01

    Bursts of action potentials within neurons and throughout networks are believed to serve roles in how neurons handle and store information, both in vivo and in vitro. Accurate detection of burst occurrences and durations are therefore crucial for many studies. A number of algorithms have been proposed to do so, but a standard method has not been adopted. This is due, in part, to many algorithms requiring the adjustment of multiple ad-hoc parameters and further post-hoc criteria in order to produce satisfactory results. Here, we broadly catalog existing approaches and present a new approach requiring the selection of only a single parameter: the number of spikes N comprising the smallest burst to consider. A burst was identified if N spikes occurred in less than T ms, where the threshold T was automatically determined from observing a probability distribution of inter-spike-intervals. Performance was compared vs. different classes of detectors on data gathered from in vitro neuronal networks grown over microelectrode arrays. Our approach offered a number of useful features including: a simple implementation, no need for ad-hoc or post-hoc criteria, and precise assignment of burst boundary time points. Unlike existing approaches, detection was not biased toward larger bursts, allowing identification and analysis of a greater range of neuronal and network dynamics. PMID:24567714

  2. Pipe crawlers: Versatile adaptations for real applications

    SciTech Connect

    Hapstack, M.; Talarek, T.R.

    1990-01-01

    A problem at the Savannah River Site requires the unique application of a pipe crawler. A number of stainless steel pipes buried in concrete require ultrasonic inspection of the heat affected zones of the welds for detection of flaws or cracks. The paper describes the utilization of an inch-worm motion pipe crawler which negotiates a 90 degree reducing elbow with significant changes in diameter and vertical sections before entering the area of concern. After a discussion of general considerations and problem description, special requirements to meet the objectives and the design approach regarding the tractor, control system, instrument carriage, and radiation protection are discussed. 2 refs., 11 figs. (MB)

  3. Dynamic simulation recalls condensate piping event

    SciTech Connect

    Farrell, R.J.; Reneberg, K.O. ); Moy, H.C. )

    1994-05-01

    This article describes how experience gained from simulating and reconstructing a condensate piping event will be used by Consolidated Edison to analyze control system problems. A cooperative effort by Con Edison and the Chemical Engineering Department at Polytechnic University used modular modeling system to investigate the probable cause of a Con Edison condensate piping event. Con Edison commissioned the work to serve as a case study for the more general problem of control systems analysis using dynamic simulation and MMS.

  4. Research on the FBG strain gauge used for the safety monitoring of high-temperature pressure pipes

    NASA Astrophysics Data System (ADS)

    Cai, Qing-mu; Liu, Yue-ming; He, Zheng-yan; Chen, Zhong-you; Huang, Chang-qing; Lou, Jun; Tian, Wei-jian

    2012-10-01

    High temperature pressure pipes were widely used in the chemical, oil companies and power plants, but the pipe burst incidents occurred from time to time, which had caused some damages on people's lives and property. Thus, in this paper, with the aim to solve this problem, a FBG (FBG: Fiber Bragg Grating) strain gauge structure which consists of three FBGs is designed and fabricated based on the theoretical strain and stress analysis. The strain gauge can be used for the real-time surface strain monitoring of high temperature pressure pipes. In the strain gauge, the elastic hightemperature alloy(10MoWVNb) is chosen as the substrate. The three FBGs with a similar performance are fabricated on the substrate with the high-temperature glue. Among the three FBGs, FBG1 is used for the horizontal strain sensing of high temperature pressure pipes., FBG2 is used for the longitudinal strain of high temperature pressure pipes, and FGB3 is used for temperature compensation. The strain gauge has a feature of high temperature resistance, temperature compensation and two-dimensional strain measurement. The experiment result shows that : the sensing ranges of temperature is 0~300°C, the transverse strain sensitivity is 1.110nm/μɛ, the temperature sensitivity is 0.0213nm/°C; The longitudinal strain sensitivity is 1.104nm/μɛ, the temperature sensitivity is 0.0212nm/°C; the temperature sensitivity is 0.0103nm/°C. Therefore, the strain gauge can meet the needs of the high temperature and pressure pipes.

  5. Fracture propagation, pipe deformation study

    SciTech Connect

    Aloe, A.; Di Candia, A.; Bramante, M.

    1983-04-15

    Shear fracture propagation has become an important research subject connected with design aspects of gas pipelines. Difficulties involved in predicting safe service conditions from pure theoretical studies require 1:1 scale experiments. Through these tests, semiempirical design criteria was formulated where the minimum level of material quality, indicated by Charpy V energy in the ductile range, is determined as a function of pipe geometry and hoop stress. Disagreements exist among these criteria. Different arrest energy predictions at high hoop stresses and different effects ascribed to the thickness have called for further research in the field. Some interesting indications were obtained about shape and size of the plastic zone ahead of the propagating crack. Burst tests have been conducted and are discussed.

  6. Flexible ocean upwelling pipe

    DOEpatents

    Person, Abraham

    1980-01-01

    In an ocean thermal energy conversion facility, a cold water riser pipe is releasably supported at its upper end by the hull of the floating facility. The pipe is substantially vertical and has its lower end far below the hull above the ocean floor. The pipe is defined essentially entirely of a material which has a modulus of elasticity substantially less than that of steel, e.g., high density polyethylene, so that the pipe is flexible and compliant to rather than resistant to applied bending moments. The position of the lower end of the pipe relative to the hull is stabilized by a weight suspended below the lower end of the pipe on a flexible line. The pipe, apart from the weight, is positively buoyant. If support of the upper end of the pipe is released, the pipe sinks to the ocean floor, but is not damaged as the length of the line between the pipe and the weight is sufficient to allow the buoyant pipe to come to a stop within the line length after the weight contacts the ocean floor, and thereafter to float submerged above the ocean floor while moored to the ocean floor by the weight. The upper end of the pipe, while supported by the hull, communicates to a sump in the hull in which the water level is maintained below the ambient water level. The sump volume is sufficient to keep the pipe full during heaving of the hull, thereby preventing collapse of the pipe.

  7. Burst Pressure Prediction of Multiple Cracks in Pipelines

    NASA Astrophysics Data System (ADS)

    Razak, N. A.; Alang, N. A.; Murad, M. A.

    2013-12-01

    Available industrial code such as ASME B1G, modified ASME B1G and DNV RP-F101 to assess pipeline defects appear more conservative for multiple crack like- defects than single crack-like defects. Thus, this paper presents burst pressure prediction of pipe with multiple cracks like defects. A finite element model was developed and the burst pressure prediction was compared with the available code. The model was used to investigate the effect of the distance between the cracks and the crack length. The coalescence diagram was also developed to evaluate the burst pressure of the multiple cracks. It was found as the distance between crack increases, the interaction effect comes to fade away and multiple cracks behave like two independent single cracks.

  8. Reusable pipe flange covers

    DOEpatents

    Holden, James Elliott; Perez, Julieta

    2001-01-01

    A molded, flexible pipe flange cover for temporarily covering a pipe flange and a pipe opening includes a substantially round center portion having a peripheral skirt portion depending from the center portion, the center portion adapted to engage a front side of the pipe flange and to seal the pipe opening. The peripheral skirt portion is formed to include a plurality of circumferentially spaced tabs, wherein free ends of the flexible tabs are formed with respective through passages adapted to receive a drawstring for pulling the tabs together on a back side of the pipe flange.

  9. Interplanetary Type IV Bursts

    NASA Astrophysics Data System (ADS)

    Hillaris, A.; Bouratzis, C.; Nindos, A.

    2016-08-01

    We study the characteristics of moving type IV radio bursts that extend to hectometric wavelengths (interplanetary type IV or type {IV}_{{IP}} bursts) and their relationship with energetic phenomena on the Sun. Our dataset comprises 48 interplanetary type IV bursts observed with the Radio and Plasma Wave Investigation (WAVES) instrument onboard Wind in the 13.825 MHz - 20 kHz frequency range. The dynamic spectra of the Radio Solar Telescope Network (RSTN), the Nançay Decametric Array (DAM), the Appareil de Routine pour le Traitement et l' Enregistrement Magnetique de l' Information Spectral (ARTEMIS-IV), the Culgoora, Hiraso, and the Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (IZMIRAN) Radio Spectrographs were used to track the evolution of the events in the low corona. These were supplemented with soft X-ray (SXR) flux-measurements from the Geostationary Operational Environmental Satellite (GOES) and coronal mass ejections (CME) data from the Large Angle and Spectroscopic Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO). Positional information of the coronal bursts was obtained by the Nançay Radioheliograph (NRH). We examined the relationship of the type IV events with coronal radio bursts, CMEs, and SXR flares. The majority of the events (45) were characterized as compact, their duration was on average 106 minutes. This type of events was, mostly, associated with M- and X-class flares (40 out of 45) and fast CMEs, 32 of these events had CMEs faster than 1000 km s^{-1}. Furthermore, in 43 compact events the CME was possibly subjected to reduced aerodynamic drag as it was propagating in the wake of a previous CME. A minority (three) of long-lived type {IV}_{{IP}} bursts was detected, with durations from 960 minutes to 115 hours. These events are referred to as extended or long duration and appear to replenish their energetic electron content, possibly from electrons escaping from the corresponding coronal

  10. Heat pipe flight experiments

    NASA Technical Reports Server (NTRS)

    Ollendorf, S.

    1973-01-01

    OAO 3 heat pipe flight experiments to check out weightlessness behavior are reported. Tested were a hollow channel screen system with helical grooves, a heat pipe with a wicking system of horizontal grooves, and a spiral artery pipe with multichannel fluid return to the evaporator. Flight experiment data proved that all heat pipe geometries containing wicking systems provided uninterrupted fluid return to the condensators during weightlessness and sufficient cooling for isothermalizing optical instruments onboard OAO.

  11. Singing Corrugated Pipes

    ERIC Educational Resources Information Center

    Crawford, Frank S.

    1974-01-01

    Presents theoretical and experimental observations made with a musical toy called Hummer consisting of a corrugated flexible plastic tube about three-feet long and one-inch diam open at both ends. Included are descriptions of three new instruments: the Water Pipe, the Gas-Pipe Corrugahorn Bugle, and the Gas-Pipe Blues Corrugahorn. (CC)

  12. Heat pipes. [technology utilization

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The development and use of heat pipes are described, including space requirements and contributions. Controllable heat pipes, and designs for automatically maintaining a selected constant temperature, are discussed which would add to the versatility and usefulness of heat pipes in industrial processing, manufacture of integrated circuits, and in temperature stabilization of electronics.

  13. The GLAST Burst Monitor

    NASA Technical Reports Server (NTRS)

    Meegan, Charles A.

    2004-01-01

    The Gamma Ray Large Area Space Telescope (GLAST) observatory, scheduled for launch in 2007, comprises the Large Area Telescope (LAT) and the GLAST Burst Monitor (GBM). spectral changes that are known to occur within GRBs. between the NASA Marshall Space Flight Center, the University of Alabama in Huntsville, and the Max Planck Institute for Extraterrestrial Physics. It consists of an array of NaI and BGO scintillation detectors operating in the 10 kev to 25 MeV range. The field of view includes the entire unocculted sky when the observatory is pointing close to the zenith. The GBM will enhance LAT observations of GRBs by extending the spectral coverage into the range of current GRB databases, and will provide a trigger for reorienting the spacecraft to observe delayed emission from bursts outside the LAT field of view. GBM is expected to trigger on about 200 bursts per year, and will provide on-board locations of strong bursts accurate to better than 10 degrees.

  14. Leaks in pipe networks

    USGS Publications Warehouse

    Pudar, Ranko S.; Liggett, James A.

    1992-01-01

    Leak detection in water-distribution systems can be accomplished by solving an inverse problem using measurements of pressure and/or flow. The problem is formulated with equivalent orifice areas of possible leaks as the unknowns. Minimization of the difference between measured and calculated heads produces a solution for the areas. The quality of the result depends on number and location of the measurements. A sensitivity matrix is key to deciding where to make measurements. Both location and magnitude of leaks are sensitive to the quantity and quality of pressure measurements and to how well the pipe friction parameters are known. The overdetermined problem (more measurements than suspected leaks) gives the best results, but some information can be derived from the underdetermined problem. The variance of leak areas, based on the quality of system characteristics and pressure data, indicates the likely accuracy of the results. The method will not substitute for more traditional leak surveys but can serve as a guide and supplement.

  15. Convection Design of Cryogenic Piping and Components

    NASA Astrophysics Data System (ADS)

    McIntosh, G. E.

    2006-04-01

    Poor thermal performance of dewars, magnet cryostats, and other cryogenic equipment is often caused by failure of the designer to recognize the impact of enclosed free convection heat transfer. This paper describes the mechanism of internal convection in piping, vapor-cooled leads, bayonets and specialty dewars. Specific examples are given in each category. Conclusions include guidelines to avoid convection heat transfer problems and rules for correctly calculating heat leak of cryogenic piping.

  16. A repeating fast radio burst.

    PubMed

    Spitler, L G; Scholz, P; Hessels, J W T; Bogdanov, S; Brazier, A; Camilo, F; Chatterjee, S; Cordes, J M; Crawford, F; Deneva, J; Ferdman, R D; Freire, P C C; Kaspi, V M; Lazarus, P; Lynch, R; Madsen, E C; McLaughlin, M A; Patel, C; Ransom, S M; Seymour, A; Stairs, I H; Stappers, B W; van Leeuwen, J; Zhu, W W

    2016-03-10

    Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star. PMID:26934226

  17. A repeating fast radio burst

    NASA Astrophysics Data System (ADS)

    Spitler, L. G.; Scholz, P.; Hessels, J. W. T.; Bogdanov, S.; Brazier, A.; Camilo, F.; Chatterjee, S.; Cordes, J. M.; Crawford, F.; Deneva, J.; Ferdman, R. D.; Freire, P. C. C.; Kaspi, V. M.; Lazarus, P.; Lynch, R.; Madsen, E. C.; McLaughlin, M. A.; Patel, C.; Ransom, S. M.; Seymour, A.; Stairs, I. H.; Stappers, B. W.; van Leeuwen, J.; Zhu, W. W.

    2016-03-01

    Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star.

  18. Cloaked Gamma-Ray Bursts

    NASA Astrophysics Data System (ADS)

    Eichler, David

    2014-06-01

    It is suggested that many gamma-ray bursts (GRBs) are cloaked by an ultrarelativistic baryonic shell that has high optical depth when the photons are manufactured. Such a shell would not fully block photons reflected or emitted from its inner surface, because the radial velocity of the photons can be less than that of the shell. This avoids the standard problem associated with GRBs that the thermal component should be produced where the flow is still obscured by high optical depth. The radiation that escapes high optical depth obeys the Amati relation. Observational implications may include (1) anomalously high ratios of afterglow to prompt emission, such as may have been the case in the recently discovered PTF 11agg, and (2) ultrahigh-energy neutrino pulses that are non-coincident with detectable GRB. It is suggested that GRB 090510, a short, very hard GRB with very little afterglow, was an exposed GRB, in contrast to those cloaked by baryonic shells.

  19. CLOAKED GAMMA-RAY BURSTS

    SciTech Connect

    Eichler, David

    2014-06-01

    It is suggested that many gamma-ray bursts (GRBs) are cloaked by an ultrarelativistic baryonic shell that has high optical depth when the photons are manufactured. Such a shell would not fully block photons reflected or emitted from its inner surface, because the radial velocity of the photons can be less than that of the shell. This avoids the standard problem associated with GRBs that the thermal component should be produced where the flow is still obscured by high optical depth. The radiation that escapes high optical depth obeys the Amati relation. Observational implications may include (1) anomalously high ratios of afterglow to prompt emission, such as may have been the case in the recently discovered PTF 11agg, and (2) ultrahigh-energy neutrino pulses that are non-coincident with detectable GRB. It is suggested that GRB 090510, a short, very hard GRB with very little afterglow, was an exposed GRB, in contrast to those cloaked by baryonic shells.

  20. GRO: Black hole models for gamma-ray bursts

    NASA Technical Reports Server (NTRS)

    Shaham, Jacob

    1994-01-01

    The possibility of creating gamma ray bursts (GRB's) from accretion flows on to black holes is investigated. The mechanism of initial energy release in the form of a burst is not understood yet. The typical time scales involved in this energy release and the initial distribution of photons as a function of energy are studied. As a first step the problem is formulated in the Minkowski spacetime for a homogeneous and isotropic burst. For an arbitrary initial distribution of photons, the equations of relativistic kinetic theory are formulated for nonequilibrium plasmas which can take into account various particle creation and annihilation processes and various scattering processes.

  1. 65. FIRE SUPPRESSION PIPES BEHIND FLAME BUCKET. PIPES TO UMBILICAL ...

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

    65. FIRE SUPPRESSION PIPES BEHIND FLAME BUCKET. PIPES TO UMBILICAL MAST IN LOWER LEFT CORNER; PIPES TO LAUNCHER IN UPPER LEFT CORNER; PIPES TO FLAME BUCKET IN LOWER RIGHT CORNER OF PHOTOGRAPH. POTABLE WATER PIPING IN UPPER RIGHT CORNER OF PHOTO. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  2. KENTUCKY STRAIGHT PIPES REPORT, DECEMBER 2002

    EPA Science Inventory

    The poor sanitary conditions and water pollution problems EPA observed in the Kentucky counties of Harlan, Martin, Bath, and Montgomery were of the highest concern. The widespread scale of both the straight pipe issues as well as package plant wastewater problems present an envir...

  3. The GLAST Burst Monitor

    SciTech Connect

    Bhat, P.N.; Briggs, M.S.; Connaughton, V.; Paciesas, W.S.; Preece, R.D.; Meegan, C.A.; Fishman, G.J.; Wilson, R.B.; Lichti, G.G.; Diehl, R.; Greiner, J.; Schoenfelder, V.; Kienlin, A. von; Kippen, R.M.; Kouveliotou, C.

    2004-09-28

    The Gamma Ray Large Area Space Telescope (GLAST) mission is a followup to the successful EGRET experiment onboard the Compton Gamma Ray Observatory (CGRO). It will provide a high-sensitivity survey of the sky in high-energy {gamma}-rays, and will perform detailed observations of persistent and transient sources. There are two experiments onboard the GLAST - the Large Area Telescope (LAT) and the GLAST Burst Monitor (GBM).The primary mission of the GBM instrument is to support the LAT in observing {gamma}-ray bursts (GRBs) by providing low-energy measurements with high time resolution and rapid burst locations over a large field-of-view ({>=} 8 sr). The GBM will complement the LAT measurements by observing GRBs in the energy range 10 keV to 30 MeV, the region of the spectral turnover in most GRBs. An important objective of the GBM is to compute the locations of GRB sources on-board the spacecraft and quickly communicate them to the LAT and to the ground to allow rapid followup observations. This information may be used to re-point the LAT towards particularly interesting burst sources that occurred outside its field-of-view. The GBM consists of 14 uncollimated scintillation detectors coupled to phototubes to measure {gamma}-ray energies and time profiles. Two types of detectors are used to obtain spectral information over a wide energy range: 12 NaI(Tl) detectors (10 keV to 1 MeV), and 2 BGO detectors (150 keV to 30 MeV). The detectors are distributed around the GLAST spacecraft to provide a large, unobstructed field of view. The 12 NaI(Tl) detectors are mounted with different orientations for use in locating GRB sources.

  4. SCIENCE Magazine: BATSE 1000 gamma-ray burst perspective

    NASA Technical Reports Server (NTRS)

    Horack, John M.

    1995-01-01

    A historical highlight and analysis of the Burst and Transient Source Experiment (BATSE), which has been in operation for more than three years and has detected more than 1,000 cosmic gamma-ray bursts is presented. The questions BATSE has answered and those it has not are assessed, along with the problems and data correlation and processing that has occured from the BATSE operation.

  5. Piping inspection instrument carriage

    SciTech Connect

    Zollinger, W.T.; Treanor, R.C.

    1993-09-20

    This invention is comprised of a pipe inspection instrument carriage for use with a pipe crawler or other locomotion means for performing internal inspections of piping surfaces. The carriage has a front leg assembly, a rear leg assembly and a central support connecting the two assemblies and for mounting an instrument arm having inspection instruments. The instrument arm has means mounted distally thereon for axially aligning the inspection instrumentation and means for extending the inspection instruments radially outward to operably position the inspection instruments on the piping interior. Also, the carriage has means for rotating the central support and the front leg assembly with respect to the rear leg assembly so that the inspection instruments azimuthally scan the piping interior. The instrument carriage allows performance of all piping inspection operations with a minimum of moving parts, thus decreasing the likelihood of performance failure.

  6. Deployable Heat Pipe Radiator

    NASA Technical Reports Server (NTRS)

    Edelstein, F.

    1975-01-01

    A 1.2- by 1.8-m variable conductance heat pipe radiator was designed, built, and tested. The radiator has deployment capability and can passively control Freon-21 fluid loop temperatures under varying loads and environments. It consists of six grooved variable conductance heat pipes attached to a 0.032-in. aluminum panel. Heat is supplied to the radiator via a fluid header or a single-fluid flexible heat pipe header. The heat pipe header is an artery design that has a flexible section capable of bending up to 90 degrees. Radiator loads as high as 850 watts were successfully tested. Over a load variation of 200 watts, the outlet temperature of the Freon-21 fluid varied by 7 F. An alternate control system was also investigated which used a variable conductance heat pipe header attached to the heat pipe radiator panel.

  7. Abrasion resistant heat pipe

    DOEpatents

    Ernst, Donald M.

    1984-10-23

    A specially constructed heat pipe for use in fluidized bed combustors. Two distinct coatings are spray coated onto a heat pipe casing constructed of low thermal expansion metal, each coating serving a different purpose. The first coating forms aluminum oxide to prevent hydrogen permeation into the heat pipe casing, and the second coating contains stabilized zirconium oxide to provide abrasion resistance while not substantially affecting the heat transfer characteristics of the system.

  8. Abrasion resistant heat pipe

    DOEpatents

    Ernst, D.M.

    1984-10-23

    A specially constructed heat pipe is described for use in fluidized bed combustors. Two distinct coatings are spray coated onto a heat pipe casing constructed of low thermal expansion metal, each coating serving a different purpose. The first coating forms aluminum oxide to prevent hydrogen permeation into the heat pipe casing, and the second coating contains stabilized zirconium oxide to provide abrasion resistance while not substantially affecting the heat transfer characteristics of the system.

  9. Internal pipe attachment mechanism

    DOEpatents

    Bast, Richard M.; Chesnut, Dwayne A.; Henning, Carl D.; Lennon, Joseph P.; Pastrnak, John W.; Smith, Joseph A.

    1994-01-01

    An attachment mechanism for repairing or extending fluid carrying pipes, casings, conduits, etc. utilizing one-way motion of spring tempered fingers to provide a mechanical connection between the attachment mechanism and the pipe. The spring tempered fingers flex to permit insertion into a pipe to a desired insertion depth. The mechanical connection is accomplished by reversing the insertion motion and the mechanical leverage in the fingers forces them outwardly against the inner wall of the pipe. A seal is generated by crushing a sealing assembly by the action of setting the mechanical connection.

  10. Internal pipe attachment mechanism

    DOEpatents

    Bast, R.M.; Chesnut, D.A.; Henning, C.D.; Lennon, J.P.; Pastrnak, J.W.; Smith, J.A.

    1994-12-13

    An attachment mechanism is described for repairing or extending fluid carrying pipes, casings, conduits, etc. utilizing one-way motion of spring tempered fingers to provide a mechanical connection between the attachment mechanism and the pipe. The spring tempered fingers flex to permit insertion into a pipe to a desired insertion depth. The mechanical connection is accomplished by reversing the insertion motion and the mechanical leverage in the fingers forces them outwardly against the inner wall of the pipe. A seal is generated by crushing a sealing assembly by the action of setting the mechanical connection. 6 figures.

  11. Underground radial pipe network

    SciTech Connect

    Peterson, D.L.

    1984-04-24

    The network, useful in conducting fluids to underground sites, is an assembly of flexible pipes or tubes, suspended from and connected to a drill pipe. The flexible pipes, assembled in a bundle, are spring biased to flare outwardly in an arcuate manner when a releasable cap on the distal end of the bundle is removed. The assembled bundle is inserted into and lowered down a bore hole. When the cap is released, the pipes flare radially and outwardly. Fluid, pumped into and through the assembly, can be directed into the underground formation for various purposes.

  12. Heat Pipe Materials Compatibility

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.; Fleischman, G. L.; Luedke, E. E.

    1976-01-01

    An experimental program to evaluate noncondensable gas generation in ammonia heat pipes was completed. A total of 37 heat pipes made of aluminum, stainless steel and combinations of these materials were processed by various techniques, operated at different temperatures and tested at low temperature to quantitatively determine gas generation rates. In order of increasing stability are aluminum/stainless combination, all aluminum and all stainless heat pipes. One interesting result is the identification of intentionally introduced water in the ammonia during a reflux step as a means of surface passivation to reduce gas generation in stainless-steel/aluminum heat pipes.

  13. External artery heat pipe

    NASA Technical Reports Server (NTRS)

    Gernert, Nelson J. (Inventor); Ernst, Donald M. (Inventor); Shaubach, Robert M. (Inventor)

    1989-01-01

    An improved heat pipe with an external artery. The longitudinal slot in the heat pipe wall which interconnects the heat pipe vapor space with the external artery is completely filled with sintered wick material and the wall of the external artery is also covered with sintered wick material. This added wick structure assures that the external artery will continue to feed liquid to the heat pipe evaporator even if a vapor bubble forms within and would otherwise block the liquid transport function of the external artery.

  14. Introduction to Heat Pipes

    NASA Technical Reports Server (NTRS)

    Ku, Jentung

    2015-01-01

    This is the presentation file for the short course Introduction to Heat Pipes, to be conducted at the 2015 Thermal Fluids and Analysis Workshop, August 3-7, 2015, Silver Spring, Maryland. NCTS 21070-15. Course Description: This course will present operating principles of the heat pipe with emphases on the underlying physical processes and requirements of pressure and energy balance. Performance characterizations and design considerations of the heat pipe will be highlighted. Guidelines for thermal engineers in the selection of heat pipes as part of the spacecraft thermal control system, testing methodology, and analytical modeling will also be discussed.

  15. Pipe crawler apparatus

    DOEpatents

    Hovis, Gregory L.; Erickson, Scott A.; Blackmon, Bruce L.

    2002-01-01

    A pipe crawler apparatus particularly useful for 3-inch and 4-inch diameter pipes is provided. The pipe crawler apparatus uses a gripping apparatus in which a free end of a piston rod is modified with a bearing retaining groove. Bearings, placed within the groove, are directed against a camming surface of three respective pivoting support members. The non-pivoting ends of the support members carry a foot-like gripping member that, upon pivoting of the support member, engages the interior wall of the pipe.

  16. Heat Pipe Planets

    NASA Technical Reports Server (NTRS)

    Moore, William B.; Simon, Justin I.; Webb, A. Alexander G.

    2014-01-01

    When volcanism dominates heat transport, a terrestrial body enters a heat-pipe mode, in which hot magma moves through the lithosphere in narrow channels. Even at high heat flow, a heat-pipe planet develops a thick, cold, downwards-advecting lithosphere dominated by (ultra-)mafic flows and contractional deformation at the surface. Heat-pipes are an important feature of terrestrial planets at high heat flow, as illustrated by Io. Evidence for their operation early in Earth's history suggests that all terrestrial bodies should experience an episode of heat-pipe cooling early in their histories.

  17. UWB dual burst transmit driver

    SciTech Connect

    Dallum, Gregory E.; Pratt, Garth C.; Haugen, Peter C.; Zumstein, James M.; Vigars, Mark L.; Romero, Carlos E.

    2012-04-17

    A dual burst transmitter for ultra-wideband (UWB) communication systems generates a pair of precisely spaced RF bursts from a single trigger event. An input trigger pulse produces two oscillator trigger pulses, an initial pulse and a delayed pulse, in a dual trigger generator. The two oscillator trigger pulses drive a gated RF burst (power output) oscillator. A bias driver circuit gates the RF output oscillator on and off and sets the RF burst packet width. The bias driver also level shifts the drive signal to the level that is required for the RF output device.

  18. X-ray burst sources

    NASA Technical Reports Server (NTRS)

    Lewin, W. H. G.

    1986-01-01

    There are about 100 bright X-ray sources in the Galaxy that are accretion-driven systems composed of a neutron star and a low mass companion that fills its critical Roche lobe. Many of these systems generate recurring X-ray bursts that are the result of thermonuclear flashes in the neutron star's surface layers, and are accompanied by a somewhat delayed optical burst due to X-ray heating of accretion disk. The Rapid Burster discovered in 1976 exhibits an interval between bursts that is strongly correlated with the energy in the preceding burst. There is no optical identification for this object.

  19. Gamma-ray bursts.

    PubMed

    Gehrels, Neil; Mészáros, Péter

    2012-08-24

    Gamma-ray bursts (GRBs) are bright flashes of gamma rays coming from the cosmos. They occur roughly once per day, typically last for tens of seconds, and are the most luminous events in the universe. More than three decades after their discovery, and after pioneering advances from space and ground experiments, they still remain mysterious. The launch of the Swift and Fermi satellites in 2004 and 2008 brought in a trove of qualitatively new data. In this Review, we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglow. PMID:22923573

  20. Gamma Ray Bursts

    NASA Technical Reports Server (NTRS)

    Gehrels, Neil; Meszaros, Peter

    2012-01-01

    Gamma-ray bursts (GRBs) are bright flashes of gamma-rays coming from the cosmos. They occur roughly once per day ,last typically lOs of seconds and are the most luminous events in the universe. More than three decades after their discovery, and after pioneering advances from space and ground experiments, they still remain mysterious. The launch of the Swift and Fermi satellites in 2004 and 2008 brought in a trove of qualitatively new data. In this review we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglows.

  1. Gamma-Ray Bursts

    NASA Astrophysics Data System (ADS)

    Gehrels, Neil; Mészáros, Péter

    2012-08-01

    Gamma-ray bursts (GRBs) are bright flashes of gamma rays coming from the cosmos. They occur roughly once per day, typically last for tens of seconds, and are the most luminous events in the universe. More than three decades after their discovery, and after pioneering advances from space and ground experiments, they still remain mysterious. The launch of the Swift and Fermi satellites in 2004 and 2008 brought in a trove of qualitatively new data. In this Review, we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglow.

  2. Theory of type I X-ray bursts - the energetics of bursts and the nuclear fuel reservoir in the envelope

    SciTech Connect

    Fujimoto, M.Y.; Sztajno, M.; Lewin, W.H.G.; Van Paradijs, J.

    1987-08-01

    A comparison is made between the observed properties of type I X-ray bursts from 4U/MXB 1636-53 and those of models of thermonuclear flashes on accreting neutron stars. Possible explanations of variations in the burst recurrence properties without an apparent correlation with accretion rate are discussed. The strongest bursts with photospheric expansion are described well by current spherically symmetric models. The observed weak bursts suggest a mechanism that can promote the inward propagation and heating of accreted fuel so as to give rise to thermonuclear runaways much earlier than expected from spherical models. A sufficient amount of fuel to feed the weak bursts can be stored in the outer layers for neutron stars with radii greater than 8 km. The proposed mechanism and fuel storage can resolve the longstanding problem of bursts in rapid succession with intervals shorter than about 10 minutes. The proposed model explains the variation of burst peak fluxes observed from 4U/MSB 1636-53. 67 references.

  3. Heat pipe methanator

    DOEpatents

    Ranken, William A.; Kemme, Joseph E.

    1976-07-27

    A heat pipe methanator for converting coal gas to methane. Gravity return heat pipes are employed to remove the heat of reaction from the methanation promoting catalyst, transmitting a portion of this heat to an incoming gas pre-heat section and delivering the remainder to a steam generating heat exchanger.

  4. These Pipes Are "Happening"

    ERIC Educational Resources Information Center

    Skophammer, Karen

    2010-01-01

    The author is blessed with having the water pipes for the school system in her office. In this article, the author describes how the breaking of the pipes had led to a very worthwhile art experience for her students. They practiced contour and shaded drawing techniques, reviewed patterns and color theory, and used their reasoning skills--all while…

  5. Gamma-ray burst theory: Back to the drawing board

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.

    1994-01-01

    Gamma-ray bursts have always been intriguing sources to study in terms of particle acceleration, but not since their discovery two decades ago has the theory of these objects been in such turmoil. Prior to the launch of Compton Gamma-Ray Observatory and observations by Burst and Transient Source Experiment (BATSE), there was strong evidence pointing to magnetized Galactic neutron stars as the sources of gamma-ray bursts. However, since BATSE the observational picture has changed dramatically, requiring much more distant and possibly cosmological sources. I review the history of gamma-ray burst theory from the era of growing consensus for nearby neutron stars to the recent explosion of halo and cosmological models and the impact of the present confusion on the particle acceleration problem.

  6. Extendable pipe crawler

    DOEpatents

    Hapstack, Mark

    1991-01-01

    A pipe crawler having a front leg assembly and a back leg assembly connected together by two air cylinders, each leg assembly having four extendable legs and a pair of actuators for sliding the extendable legs radially outward to increase the range of the legs when the pipe crawler enters a section of a pipe having a larger diameter. The crawler crawls by "inchworm"-like motion, the front leg assembly and back leg assembly alternately engaging and disengaging the wall of the pipe to hold the pipe crawler as the air cylinders alternately advance the front leg assembly and bring up the rear leg assembly. The pair of actuators of each leg assembly are parallel, adjacent and opposing acting so that each slides two adjacent extendable legs radially outward.

  7. Extendable pipe crawler

    DOEpatents

    Hapstack, M.

    1991-05-28

    A pipe crawler is described having a front leg assembly and a back leg assembly connected together by two air cylinders, each leg assembly having four extendable legs and a pair of actuators for sliding the extendable legs radially outward to increase the range of the legs when the pipe crawler enters a section of a pipe having a larger diameter. The crawler crawls by inchworm'-like motion, the front leg assembly and back leg assembly alternately engaging and disengaging the wall of the pipe to hold the pipe crawler as the air cylinders alternately advance the front leg assembly and bring up the rear leg assembly. The pair of actuators of each leg assembly are parallel, adjacent and opposing acting so that each slides two adjacent extendable legs radially outward. 5 figures.

  8. New video probe sees gas pipe abnormalities

    SciTech Connect

    Swenson, P. )

    1992-04-01

    This paper reports that initial results indicate the PLS 3000 pipeline inspection system can significantly reduce the time and cost required to locate and repair leaks in low-pressure natural gas distribution system without interrupting the flow of gas. The system uses a sealed miniature color TV probe into live low-pressure piping to see the leak and other piping problems, such as water infiltration, pipe distortions, structural cracks, broken or misaligned service connections and the presence of foreign matter. The camera is housed in a sealed stainless steel probe that is 1.96-in in diameter and 5.7-in. long. It can travel up to 6000 linear ft in 3- 4- and 6-in piping from a single 3-ft by 5-ft excavation. The probe enters the pipe through a patented Easy Dual Access fitting. The fitting allows the technician to cut into the pipe, remove the coupon and insert the camera probe under sealed conditions. At the conclusion of the examination, the technician seals the access hole with a gasketed steel band clamp.

  9. Analysis of Rotary Bayonets and Piping

    SciTech Connect

    Chess, K.; Wendlandt, J.; /Fermilab

    1988-08-19

    This report quantifies certain characteristics of the rotary bayonets and associated platform piping on the DO detector. The Vacuum Jacketed 4-inch x 6-inch and 1.5-inch x 3-inch and the 4-inch and 6-inch vacuum pipe articulating jumpers are considered here. The values of greatest importance are the forces required at the bayonet moment arms given in Table II and the stresses summarized in Table III. The forces required should be noted and checked that they are acceptable to the problem. The maximum bending stresses of the vacuum pipes do not exceed 1000 psi and are essentially negligible. The 4-inch x 6-inch vacuum jacketed line experiences the maximum bending stress of 10,300 psi. According to code B31.1, the maximum allowable bending stress is 25,500 psi. The major sources of error in these calculations should be summarized. First, all weights used were approximations and all lengths used were scaled from drawings. Second, while the FRAME MAC{trademark} models resemble the vacuum pipe articulating jumpers, they are definitely simplified. For instance, they do not account for the different stiffnesses of the unions. Finally, the bayonets in the ANSYS models consist of an outer jacket and an inner pipe fixed together at the end of the male sleeve. The actual bayonets are more complex and are composed of various sizes of tubes and pipes which affect the stiffness of the section.

  10. Common causes of material degradation in buried piping

    SciTech Connect

    Jenkins, C.F.

    1997-01-20

    Buried pipe may fail for innumerable reasons. Causes can be mechanical damage/breakage, chemically initiated corrosion, or a combination. Failures may originate either internally or externally on the pipe. They may be related to flaws in the design, to excessive or unanticipated internal pressure or ground level loading, and/or to poor or uncertain installation practice. Or the pipe may simply ``wear out`` in service. Steel is strong and very forgiving in underground applications, especially with regard to backfill. However, soil support developed through densification or compaction is critical for brittle concrete and vitrified clay tile pipe, and is very important for cast iron and plastic pipe. Chemistry of the soil determines whether or not it will enhance corrosion or other types of degradation. Various causes and mechanisms for deterioration of buried pipe are indicated. Some peculiarities of the different materials of construction are characterized. Repair methods and means to circumvent special problems are described.

  11. Swift's 500th Gamma Ray Burst

    NASA Video Gallery

    On April 13, 2010, NASA's Swift Gamma-ray Burst Explorer satellite discovered its 500th burst. Swift's main job is to quickly localize each gamma-ray burst (GRB), report its position so that others...

  12. Burst propagation in Texas Helimak

    NASA Astrophysics Data System (ADS)

    Pereira, F. A. C.; Toufen, D. L.; Guimarães-Filho, Z. O.; Caldas, I. L.; Gentle, K. W.

    2016-05-01

    We present investigations of extreme events (bursts) propagating in the Texas Helimak, a toroidal plasma device in which the radial electric field can be changed by application of bias. In the experiments analyzed, a large grid of Langmuir probes measuring ion saturation current fluctuations is used to study the burst propagation and its dependence on the applied bias voltage. We confirm previous results reported on the turbulence intermittency in the Texas Helimak, extending them to a larger radial interval with a density ranging from a uniform decay to an almost uniform value. For our analysis, we introduce an improved procedure, based on a multiprobe bidimensional conditional averaging method, to assure precise determination of burst statistical properties and their spatial profiles. We verify that intermittent bursts have properties that vary in the radial direction. The number of bursts depends on the radial position and on the applied bias voltage. On the other hand, the burst characteristic time and size do not depend on the applied bias voltage. The bias voltage modifies the vertical and radial burst velocity profiles differently. The burst velocity is smaller than the turbulence phase velocity in almost all the analyzed region.

  13. An optical method for measuring the thickness of a falling condensate in gravity assisted heat pipe

    NASA Astrophysics Data System (ADS)

    Kasanický, Martin; Lenhard, Richard; Kaduchová, Katarína; Malcho, Milan

    2015-05-01

    A large number of variables is the main problem of designing systems which uses heat pipes, whether it is a traditional - gravity, or advanced - capillary, pulsating, advanced heat pipes. This article is a methodology for measuring the thickness of the falling condensate in gravitational heat pipes, with using the optical triangulation method, and the evaluation of risks associated with this method.

  14. Early On-Orbit Operation of the Loop Heat Pipe System on the Swift BAT Instrument

    NASA Technical Reports Server (NTRS)

    Ottenstein, Laura; Ku, Jentung; Choi, Mike; Feenan, Dave

    2005-01-01

    The Burst Alert Telescope (BAT) is one of three instruments on the Swift satellite. Two Loop Heat Pipes (LHP's), one at either side of the BAT's Detector Array Plate (DAP), transfer heat to a common radiator for rejection to space. This viewgraph presentation provides information on LHP design for the BAT, and the performance of the LHPs in orbit.

  15. Quantum Key Based Burst Confidentiality in Optical Burst Switched Networks

    PubMed Central

    Balamurugan, A. M.; Sivasubramanian, A.

    2014-01-01

    The optical burst switching (OBS) is an emergent result to the technology concern that could achieve a feasible network in future. They are endowed with the ability to meet the bandwidth requirement of those applications that require intensive bandwidth. There are more domains opening up in the OBS that evidently shows their advantages and their capability to face the future network traffic. However, the concept of OBS is still far from perfection facing issues in case of security threat. The transfer of optical switching paradigm to optical burst switching faces serious downfall in the fields of burst aggregation, routing, authentication, dispute resolution, and quality of service (QoS). This paper deals with employing RC4 (stream cipher) to encrypt and decrypt bursts thereby ensuring the confidentiality of the burst. Although the use of AES algorithm has already been proposed for the same issue, by contrasting the two algorithms under the parameters of burst encryption and decryption time, end-to-end delay, it was found that RC4 provided better results. This paper looks to provide a better solution for the confidentiality of the burst in OBS networks. PMID:24578663

  16. Quantum key based burst confidentiality in optical burst switched networks.

    PubMed

    Balamurugan, A M; Sivasubramanian, A

    2014-01-01

    The optical burst switching (OBS) is an emergent result to the technology concern that could achieve a feasible network in future. They are endowed with the ability to meet the bandwidth requirement of those applications that require intensive bandwidth. There are more domains opening up in the OBS that evidently shows their advantages and their capability to face the future network traffic. However, the concept of OBS is still far from perfection facing issues in case of security threat. The transfer of optical switching paradigm to optical burst switching faces serious downfall in the fields of burst aggregation, routing, authentication, dispute resolution, and quality of service (QoS). This paper deals with employing RC4 (stream cipher) to encrypt and decrypt bursts thereby ensuring the confidentiality of the burst. Although the use of AES algorithm has already been proposed for the same issue, by contrasting the two algorithms under the parameters of burst encryption and decryption time, end-to-end delay, it was found that RC4 provided better results. This paper looks to provide a better solution for the confidentiality of the burst in OBS networks. PMID:24578663

  17. Comets, X-ray bursts, and gamma-ray bursts

    NASA Technical Reports Server (NTRS)

    Katz, J. I.

    1986-01-01

    The proposal, revived by Tremaine and Zytkow (1985), that accretion of comets by neutron stars may be the origin of gamma-ray bursts is considered. This mechanism has difficulty accounting for the observed gamma-ray spectrum and optical counterparts of the bursts. The survival of comets near supernovae is investigated. Ablation rates and the thermal structure of an ablating surface layer are calculated. In some circumstances, mechanical disruption will erode a comet more rapidly than evaporation. The accretion of comets by neutron stars may produce a class of X-ray burst sources with novel properties.

  18. Piping stress handbook. Second edition

    SciTech Connect

    Helguero, V.

    1986-01-01

    This abridged volume contains the following: Coefficients of thermal expansion. Allowable stress range for ANSI/ASME Power Piping Code B31.1. Stress intensification and flexibility factors. Pressure and stress ratios. Design criteria for allowable loads, moment, and stresses. Properties of pipe. Weight and dimensions of pipe and components. Pipe support selection and design. Fundamentals of expansion joints. Index.

  19. Experimenting with a "Pipe" Whistle

    ERIC Educational Resources Information Center

    Stafford, Olga

    2012-01-01

    A simple pipe whistle can be made using pieces of PVC pipe. The whistle can be used to measure the resonant frequencies of open or closed pipes. A slightly modified version of the device can be used to also investigate the interesting dependence of the sound frequencies produced on the orifice-to-edge distance. The pipe whistle described here…

  20. Flexible ultrasonic pipe inspection apparatus

    DOEpatents

    Jenkins, C.F.; Howard, B.D.

    1994-01-01

    Pipe crawlers, pipe inspection {open_quotes}rabbits{close_quotes} and similar vehicles are widely used for inspecting the interior surfaces of piping systems, storage tanks and process vessels for damaged or flawed structural features. This paper describes the design of a flexible, modular ultrasonic pipe inspection apparatus.

  1. Gas pipe explorer robot

    NASA Technical Reports Server (NTRS)

    Wilcox, Brian (Inventor)

    2004-01-01

    A gas pipe explorer formed of a plurality of connecting elements, and an articulation element between the connected elements. The connected elements include drive capabilities, and the articulation element allows the connected elements to traverse gas pipes of arbitrary shapes and sizes. A sensor may sends the characteristics of the gas pipe, and the communication element may send back those sends characteristics. The communication can be wired, over a tether connecting the device to a remote end. Alternatively, the connection can be wireless, driven by either a generator or a battery.

  2. An electrohydrodynamic heat pipe.

    NASA Technical Reports Server (NTRS)

    Jones, T. B.

    1972-01-01

    A heat pipe of new design, using an electrode structure to orient and guide the dielectric liquid phase flow, is proposed. Analysis indicates that the operation of the electrohydrodynamic heat pipe is in direct analogy to capillary devices, with the polarization force acting in place of capillarity. Advantages of these new heat pipes include greatly reduced liquid friction, electrohydrodynamically enhanced evaporation and condensation heat transfer, and a possible voltage-controlled on/off feature. Preliminary calculations indicate that relatively high performance devices are possible.

  3. Electrohydrodynamic heat pipes.

    NASA Technical Reports Server (NTRS)

    Jones, T. B.

    1973-01-01

    An electrohydrodynamic heat pipe of radical design is proposed which substitutes polarization electrohydrodynamic force effects for capillarity in collecting, guiding, and pumping a condensate liquid phase. The discussed device is restricted to the use of dielectric liquids as working fluids. Because of the relatively poor thermal transport properties of these liquids, capillary heat pipes using these liquids have not been high performance devices. The employment of the electrohydrodynamic concept should enhance this performance and help fill the performance gap that exists in the temperature range from 250 F to 750 F for 'conventional' capillary heat pipes.

  4. Large variable conductance heat pipe. Transverse header

    NASA Technical Reports Server (NTRS)

    Edelstein, F.

    1975-01-01

    The characteristics of gas-loaded, variable conductance heat pipes (VCHP) are discussed. The difficulties involved in developing a large VCHP header are analyzed. The construction of the large capacity VCHP is described. A research project to eliminate some of the problems involved in large capacity VCHP operation is explained.

  5. Improved Thin, Flexible Heat Pipes

    NASA Technical Reports Server (NTRS)

    Rosenfeld, John H.; Gernert, Nelson J.; Sarraf, David B.; Wollen, Peter J.; Surina, Frank C.; Fale, John E.

    2004-01-01

    Flexible heat pipes of an improved type are fabricated as layers of different materials laminated together into vacuum- tight sheets or tapes. In comparison with prior flexible heat pipes, these flexible heat pipes are less susceptible to leakage. Other advantages of these flexible heat pipes, relative to prior flexible heat pipes, include high reliability and greater ease and lower cost of fabrication. Because these heat pipes are very thin, they are highly flexible. When coated on outside surfaces with adhesives, these flexible heat pipes can be applied, like common adhesive tapes, to the surfaces of heat sinks and objects to be cooled, even if those surfaces are curved.

  6. AutoPIPE Extract Program

    SciTech Connect

    Cline, Barbara E.

    1993-07-02

    The AutoPIPE Extract Program (APEX) provides an interface between CADAM (Computer Aided Design and Manufacturing) Release 21 drafting software and the AutoPIPE, Version 4.4, piping analysis program. APEX produces the AutoPIPE batch input file that corresponds to the piping shown in a CADAM model. The card image file contains header cards, material cards, and pipe cross section cards as well as tee, bend, valve, and flange cards. Node numbers are automatically generated. APEX processes straight pipe, branch lines and ring geometries.

  7. AutoPIPE Extract Program

    Energy Science and Technology Software Center (ESTSC)

    1993-07-02

    The AutoPIPE Extract Program (APEX) provides an interface between CADAM (Computer Aided Design and Manufacturing) Release 21 drafting software and the AutoPIPE, Version 4.4, piping analysis program. APEX produces the AutoPIPE batch input file that corresponds to the piping shown in a CADAM model. The card image file contains header cards, material cards, and pipe cross section cards as well as tee, bend, valve, and flange cards. Node numbers are automatically generated. APEX processes straightmore » pipe, branch lines and ring geometries.« less

  8. Gamma-Ray Burst Physics with GLAST

    SciTech Connect

    Omodei, N.; /INFN, Pisa

    2006-10-06

    The Gamma-ray Large Area Space Telescope (GLAST) is an international space mission that will study the cosmos in the energy range 10 keV-300 GeV, the upper end of which is one of the last poorly observed region of the celestial electromagnetic spectrum. The ancestor of the GLAST/LAT was the Energetic Gamma Ray Experiment Telescope (EGRET) detector, which flew onboard the Compton Gamma Ray Observatory (CGRO). The amount of information and the step forward that the high energy astrophysics made thanks to its 9 years of observations are impressive. Nevertheless, EGRET uncovered the tip of the iceberg, raising many questions, and it is in the light of EGRET's results that the great potential of the next generation gamma-ray telescope can be appreciated. GLAST will have an imaging gamma-ray telescope, the Large Area Telescope (LAT) vastly more capable than instruments own previously, as well as a secondary instrument, the GLAST Bursts Monitor, or GBM, to augment the study of gamma-ray bursts. Gamma-Ray Bursts (GRBs) science is one of the most exciting challenges for the GLAST mission, exploring the high energy emission of one of the most intense phenomena in the sky, shading light on various problems: from the acceleration of particles to the emission processes, to more exotic physics like Quantum Gravity effect. In this paper we report the work done so far in the simulation development as well as the study of the LAT sensitivity to GRB.

  9. Burst Firing Enhances Neural Output Correlation

    PubMed Central

    Chan, Ho Ka; Yang, Dong-Ping; Zhou, Changsong; Nowotny, Thomas

    2016-01-01

    Neurons communicate and transmit information predominantly through spikes. Given that experimentally observed neural spike trains in a variety of brain areas can be highly correlated, it is important to investigate how neurons process correlated inputs. Most previous work in this area studied the problem of correlation transfer analytically by making significant simplifications on neural dynamics. Temporal correlation between inputs that arises from synaptic filtering, for instance, is often ignored when assuming that an input spike can at most generate one output spike. Through numerical simulations of a pair of leaky integrate-and-fire (LIF) neurons receiving correlated inputs, we demonstrate that neurons in the presence of synaptic filtering by slow synapses exhibit strong output correlations. We then show that burst firing plays a central role in enhancing output correlations, which can explain the above-mentioned observation because synaptic filtering induces bursting. The observed changes of correlations are mostly on a long time scale. Our results suggest that other features affecting the prevalence of neural burst firing in biological neurons, e.g., adaptive spiking mechanisms, may play an important role in modulating the overall level of correlations in neural networks. PMID:27242499

  10. Type 2 and type 3 burst theory

    NASA Technical Reports Server (NTRS)

    Smith, D. F.

    1973-01-01

    The present state of the theory of type 3 bursts is reviewed by dividing the problem into the exciting agency, radiation source, and propagation of radiation between the source and the observer. In-situ measurements indicate that the excitors are electron streams of energy about 40 keV which are continuously relaxing. An investigation of neutralization of an electron stream indicates that n sub s is much less than 100,000 n sub e, where n sub s is the stream density and n sub e the coronal electron density. In situ observations are consistent with this result. An analysis of propagation of electrons in the current sheets of coronal streamers shows that such propagation at heights greater than 1 solar radius is impossible. The mechanisms for radiation are reviewed; it is shown that fundamental radiation at high frequencies (approximately 100 MHz) is highly beamed in the radial direction and that near the earth second harmonic radiation must be dominant. Because of beaming of the fundamental at high frequencies, it can often be quite weak near the limb so that the second harmonic is dominant. In considering propagation to the observer, the results of scattering of radiation are discussed. The present state of the theory of type 2 bursts is reviewed in the same manner as type 3 bursts.

  11. Bursting the Taylor cone bubble

    NASA Astrophysics Data System (ADS)

    Pan, Zhao; Truscott, Tadd

    2014-11-01

    A soap bubble fixed on a surface and placed in an electric field will take on the shape of a cone rather than constant curvature (dome) when the electrical field is not present. The phenomenon was introduced by J. Zeleny (1917) and studied extensively by C.T. Wilson & G.I. Taylor (1925). We revisit the Taylor cone problem by studying the deformation and bursting of soap bubbles in a point charge electric field. A single bubble takes on the shape of a cone in the electric field and a high-speed camera equipped with a micro-lens is used to observe the unsteady dynamics at the tip. Rupture occurs as a very small piece of the tip is torn away from the bubble toward the point charge. Based on experiments, a theoretical model is developed that predicts when rupture should occur. This study may help in the design of foam-removal techniques in engineering and provide a better understanding of an electrified air-liquid interface.

  12. Cosmological gamma-ray bursts

    NASA Technical Reports Server (NTRS)

    Paczynski, Bohdan

    1991-01-01

    The distribution in angle and flux of gamma-ray bursts indicates that the majority of gamma-ray bursters are at cosmological distances, i.e., at z of about 1. The rate is then about 10 exp -8/yr in a galaxy like the Milky Way, i.e., orders of magnitude lower than the estimated rate for collisions between neutron stars in close binary systems. The energy per burst is about 10 exp 51 ergs, assuming isotropic emission. The events appear to be less energetic and more frequent if their emission is strongly beamed. Some tests for the distance scale are discussed: a correlation between the burst's strength and its spectrum; the absorption by the Galactic gas below about 2 keV; the X-ray tails caused by forward scattering by the Galactic dust; about 1 month recurrence of some bursts caused by gravitational lensing by foreground galaxies; and a search for gamma-ray bursts in M31. The bursts appear to be a manifestation of something exotic, but conventional compact objects can provide an explanation. The best possibility is offered by a decay of a bindary composed of a spinning-stellar-mass black-hole primary and a neutron or a strange-quark star secondary. In the final phase the secondary is tidally disrupted, forms an accretion disk, and up to 10 exp 54 ergs are released. A very small fraction of this energy powers the gamma-ray burst.

  13. Branch-pipe-routing approach for ships using improved genetic algorithm

    NASA Astrophysics Data System (ADS)

    Sui, Haiteng; Niu, Wentie

    2016-05-01

    Branch-pipe routing plays fundamental and critical roles in ship-pipe design. The branch-pipe-routing problem is a complex combinatorial optimization problem and is thus difficult to solve when depending only on human experts. A modified genetic-algorithm-based approach is proposed in this paper to solve this problem. The simplified layout space is first divided into threedimensional (3D) grids to build its mathematical model. Branch pipes in layout space are regarded as a combination of several two-point pipes, and the pipe route between two connection points is generated using an improved maze algorithm. The coding of branch pipes is then defined, and the genetic operators are devised, especially the complete crossover strategy that greatly accelerates the convergence speed. Finally, simulation tests demonstrate the performance of proposed method.

  14. An electrohydrodynamic heat pipe

    NASA Technical Reports Server (NTRS)

    Jones, T. B.

    1972-01-01

    Dielectric liquid for transfer of heat provides liquid flow from the condenser section to the evaporator section in conventional heat pipes. Working fluid is guided or pumped by an array of wire electrodes connected to a high-voltage source.

  15. Heat pipe manufacturing study

    NASA Technical Reports Server (NTRS)

    Edelstein, F.

    1974-01-01

    Heat pipe manufacturing methods are examined with the goal of establishing cost effective procedures that will ultimately result in cheaper more reliable heat pipes. Those methods which are commonly used by all heat pipe manufacturers have been considered, including: (1) envelope and wick cleaning, (2) end closure and welding, (3) mechanical verification, (4) evacuation and charging, (5) working fluid purity, and (6) charge tube pinch off. The study is limited to moderate temperature aluminum and stainless steel heat pipes with ammonia, Freon-21 and methanol working fluids. Review and evaluation of available manufacturers techniques and procedures together with the results of specific manufacturing oriented tests have yielded a set of recommended cost-effective specifications which can be used by all manufacturers.

  16. Miniature pipe crawler tractor

    DOEpatents

    McKay, Mark D.; Anderson, Matthew O.; Ferrante, Todd A.; Willis, W. David

    2000-01-01

    A pipe crawler tractor may comprise a half tractor assembly having a first base drive wheel, a second base drive wheel, and a top drive wheel. The drive wheels are mounted in spaced-apart relation so that the top drive wheel is positioned between the first and second base drive wheels. The mounting arrangement is also such that the first and second base drive wheels contact the inside surface of the pipe at respective first and second positions and so that the top drive wheel contacts the inside surface of the pipe at a third position, the third position being substantially diametrically opposed to the first and second positions. A control system connected to the half tractor assembly controls the rotation of the first base wheel, the second base wheel, and the top drive wheel to move the half tractor assembly within the pipe.

  17. Heat pipe development

    NASA Technical Reports Server (NTRS)

    Bienart, W. B.

    1973-01-01

    The objective of this program was to investigate analytically and experimentally the performance of heat pipes with composite wicks--specifically, those having pedestal arteries and screwthread circumferential grooves. An analytical model was developed to describe the effects of screwthreads and screen secondary wicks on the transport capability of the artery. The model describes the hydrodynamics of the circumferential flow in triangular grooves with azimuthally varying capillary menisci and liquid cross-sections. Normalized results were obtained which give the influence of evaporator heat flux on the axial heat transport capability of the arterial wick. In order to evaluate the priming behavior of composite wicks under actual load conditions, an 'inverted' glass heat pipe was designed and constructed. The results obtained from the analysis and from the tests with the glass heat pipe were applied to the OAO-C Level 5 heat pipe, and an improved correlation between predicted and measured evaporator and transport performance were obtained.

  18. Heat Pipe Systems

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The heat pipe was developed to alternately cool and heat without using energy or any moving parts. It enables non-rotating spacecraft to maintain a constant temperature when the surface exposed to the Sun is excessively hot and the non Sun-facing side is very cold. Several organizations, such as Tropic-Kool Engineering Corporation, joined NASA in a subsequent program to refine and commercialize the technology. Heat pipes have been installed in fast food restaurants in areas where humid conditions cause materials to deteriorate quickly. Moisture removal was increased by 30 percent in a Clearwater, FL Burger King after heat pipes were installed. Relative humidity and power consumption were also reduced significantly. Similar results were recorded by Taco Bell, which now specifies heat pipe systems in new restaurants in the Southeast.

  19. BEAM PIPE DESORPTION RATE IN RHIC.

    SciTech Connect

    HUANG, H.; FISCHER, W.; HE, P.; HSEUH, H.C.; IRISO, U.; PTITSYN, V.; TRBOJEVIC, D.; WEI, J.; YANG, S.Y.

    2006-06-23

    In the past, an increase of beam intensity in RHIC has caused several decades of pressure rises in the warm sections during operation. This has been a major factor limiting the RHIC luminosity. About 430 meters of NEG coated beam pipes have been installed in the warm sections to ameliorate this problem. Beam ion induced desorption is one possible cause of pressure rises. A series beam studies in RHIC has been dedicated to estimate the desorption rate of various beam pipes (regular and NEG coated) at various warm sections. Correctors were used to generate local beam losses and consequently local pressure rises. The experimental results are presented and analyzed in this paper.

  20. Neurophysiology of pipe flow

    NASA Astrophysics Data System (ADS)

    Barkley, Dwight

    2014-11-01

    This work explores the connection between the transition to turbulence in pipe flow and the dynamics of excitable media, as exemplified by nerve cells. The primary goal is to leverage years of extensive analysis of neural systems to understand the dynamics of transitional turbulence. To demonstrate the predictive nature of the approach, model simulations will be presented for puffs in pipe flow for cases not previously studied experimentally.

  1. Freezable heat pipe

    DOEpatents

    Ernst, Donald M.; Sanzi, James L.

    1981-02-03

    A heat pipe whose fluid can be repeatedly frozen and thawed without damage to the casing. An additional part is added to a conventional heat pipe. This addition is a simple porous structure, such as a cylinder, self-supporting and free standing, which is dimensioned with its diameter not spanning the inside transverse dimension of the casing, and with its length surpassing the depth of maximum liquid.

  2. 30 CFR 57.3461 - Rock bursts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Rock bursts. 57.3461 Section 57.3461 Mineral...-Underground Only § 57.3461 Rock bursts. (a) Operators of mines which have experienced a rock burst shall— (1) Within twenty four hours report to the nearest MSHA office each rock burst which: (i) Causes persons...

  3. 30 CFR 57.3461 - Rock bursts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Rock bursts. 57.3461 Section 57.3461 Mineral...-Underground Only § 57.3461 Rock bursts. (a) Operators of mines which have experienced a rock burst shall— (1) Within twenty four hours report to the nearest MSHA office each rock burst which: (i) Causes persons...

  4. 30 CFR 57.3461 - Rock bursts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Rock bursts. 57.3461 Section 57.3461 Mineral...-Underground Only § 57.3461 Rock bursts. (a) Operators of mines which have experienced a rock burst shall— (1) Within twenty four hours report to the nearest MSHA office each rock burst which: (i) Causes persons...

  5. 30 CFR 57.3461 - Rock bursts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Rock bursts. 57.3461 Section 57.3461 Mineral...-Underground Only § 57.3461 Rock bursts. (a) Operators of mines which have experienced a rock burst shall— (1) Within twenty four hours report to the nearest MSHA office each rock burst which: (i) Causes persons...

  6. 30 CFR 57.3461 - Rock bursts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Rock bursts. 57.3461 Section 57.3461 Mineral...-Underground Only § 57.3461 Rock bursts. (a) Operators of mines which have experienced a rock burst shall— (1) Within twenty four hours report to the nearest MSHA office each rock burst which: (i) Causes persons...

  7. Radiative Transfer In Gamma-Ray Bursts

    NASA Astrophysics Data System (ADS)

    Beloborodov, Andrei

    We propose to develop state-of-the-art numerical tools for radiative transfer calculations in gamma-ray bursts (GRBs). We will investigate two problems: (1) Production and heating of photons at the early (opaque) stage of the explosion, which controls the brightness and spectral shape of the jet photospheric emission. (2) Transfer of GRB radiation through the external blast wave. Our recent results suggest that this transfer generates the GeV flash observed in GRBs, providing key information on the explosion and its progenitor. We will test our models against observations.

  8. Bursting frequency prediction in turbulent boundary layers

    SciTech Connect

    LIOU,WILLIAM W.; FANG,YICHUNG

    2000-02-01

    The frequencies of the bursting events associated with the streamwise coherent structures of spatially developing incompressible turbulent boundary layers were predicted using global numerical solution of the Orr-Sommerfeld and the vertical vorticity equations of hydrodynamic stability problems. The structures were modeled as wavelike disturbances associated with the turbulent mean flow. The global method developed here involves the use of second and fourth order accurate finite difference formula for the differential equations as well as the boundary conditions. An automated prediction tool, BURFIT, was developed. The predicted resonance frequencies were found to agree very well with previous results using a local shooting technique and measured data.

  9. Do gamma-ray burst sources repeat?

    NASA Technical Reports Server (NTRS)

    Meegan, C. A.; Hartmann, D. H.; Brainerd, J. J.; Briggs, M.; Paciesas, W. S.; Pendleton, G.; Kouveliotou, C.; Fishman, G.; Blumenthal, G.; Brock, M.

    1994-01-01

    The demonstration of repeated gamma-ray bursts from an individual source would severely constrain burst source models. Recent reports of evidence for repetition in the first BATSE burst catalog have generated renewed interest in this issue. Here, we analyze the angular distribution of 585 bursts of the second BATSE catalog (Meegan et al. 1994). We search for evidence of burst recurrence using the nearest and farthest neighbor statistic ad the two-point angular correlation function. We find the data to be consistent with the hypothesis that burst sources do not repeat; however, a repeater fraction of up to about 20% of the bursts cannot be excluded.

  10. Cosmic gamma-ray bursts

    NASA Astrophysics Data System (ADS)

    Vedrenne, G.

    1981-06-01

    The general characteristics of gamma-ray bursts are considered. During the period from 1967 to 1977 62 gamma-ray bursts were discovered. Between September 1978 and December 1980 more than 40 bursts were observed with the aid of interplanetary spacecraft, including the Pioneer Venus Orbiter, ISEE-C, Helios B, Vela, Prognoz 7, Venera 11, and Venera 12. The time structures are discussed along with the spectra, and the burst intensity distribution. Attention is given to events observed on March 5, April 6, November 4, and November 19, 1979, taking into account the location of each event. The implications of the more recent results are discussed. It is pointed out that for a better understanding of the origin of the emissions, it is necessary to have a coordinated observation program with several satellites separated by large distances.

  11. STEALTH: a Lagrange explicit finite difference code for solids, structural, and thermohydraulic analysis. Volume 6: piping systems manual. Computer code manual

    SciTech Connect

    Cohen, L.M.

    1982-03-01

    This volume documents the STEALTH piping numerical code, which can simulate the time-dependent flow phenomena that occur in piping systems. This volume also contains the input instructions for the STEALTH piping code, and a sample problem of a pipe flow simulation.

  12. X-ray bursts: Observation versus theory

    NASA Technical Reports Server (NTRS)

    Lewin, W. H. G.

    1981-01-01

    Results of various observations of common type I X-ray bursts are discussed with respect to the theory of thermonuclear flashes in the surface layers of accreting neutron stars. Topics covered include burst profiles; irregular burst intervals; rise and decay times and the role of hydrogen; the accuracy of source distances; accuracy in radii determination; radius increase early in the burst; the super Eddington limit; temperatures at burst maximum; and the role of the magnetic field.

  13. Steady advance of coal and gas bursts

    NASA Astrophysics Data System (ADS)

    Shanbing, Yu

    1988-02-01

    This paper establishes a one-dimensional model to analyse the mechanism of coal and gas bursts. It is found that the intrinsic factor governing bursts is the coupling of the initiation of the moving of coal fragments with the gas seepage. A typical (strong) burst can be treated as a steady advance process. The significant dimensionless parameters concerning bursts and an approximate burst criterion are given, and they are in good agreement with the statistics of field data.

  14. Gamma-ray burst models.

    PubMed

    King, Andrew

    2007-05-15

    I consider various possibilities for making gamma-ray bursts, particularly from close binaries. In addition to the much-studied neutron star+neutron star and black hole+neutron star cases usually considered good candidates for short-duration bursts, there are also other possibilities. In particular, neutron star+massive white dwarf has several desirable features. These systems are likely to produce long-duration gamma-ray bursts (GRBs), in some cases definitely without an accompanying supernova, as observed recently. This class of burst would have a strong correlation with star formation and occur close to the host galaxy. However, rare members of the class need not be near star-forming regions and could have any type of host galaxy. Thus, a long-duration burst far from any star-forming region would also be a signature of this class. Estimates based on the existence of a known progenitor suggest that this type of GRB may be quite common, in agreement with the fact that the absence of a supernova can only be established in nearby bursts. PMID:17293332

  15. Optimum design for pipe-support allocation against seismic loading

    SciTech Connect

    Hara, Fumio; Iwasaki, Akira

    1996-12-01

    This paper deals with the optimum design methodology of a piping system subjected to a seismic design loading to reduce its dynamic response by selecting the location of pipe supports and whereby reducing the number of pipe supports to be used. The author employs the Genetic Algorithm for obtaining a reasonably optimum solution of the pipe support location, support capacity and number of supports. The design condition specified by the support location, support capacity and the number of supports to be used is encored by an integer number string for each of the support allocation candidates and they prepare many strings for expressing various kinds of pipe-support allocation state. Corresponding to each string, the authors evaluate the seismic response of the piping system to the design seismic excitation and apply the Genetic Algorithm to select the next generation candidates of support allocation to improve the seismic design performance specified by a weighted linear combination of seismic response magnitude, support capacity and the number of supports needed. Continuing this selection process, they find a reasonably optimum solution to the seismic design problem. They examine the feasibility of this optimum design method by investigating the optimum solution for 5, 7 and 10 degree-of-freedom models of piping system, and find that this method can offer one a theoretically feasible solution to the problem. They will be, thus, liberated from the severe uncertainty of damping value when the pipe support guaranties the design capacity of damping. Finally, they discuss the usefulness of the Genetic Algorithm for the seismic design problem of piping systems and some sensitive points when it will be applied to actual design problems.

  16. What Will Colleges Do when the Bubble Bursts?

    ERIC Educational Resources Information Center

    Shaw, Jane S.

    2011-01-01

    The problem facing American colleges and universities is larger than even the term "bubble" implies. A bursting bubble would force change on the more than four thousand postsecondary institutions in the United States, but something even more destructive is going to hit higher education, probably at the same time. The major sign that a bubble is…

  17. Pipe crack identification based on finite element method of second generation wavelets

    NASA Astrophysics Data System (ADS)

    Ye, Junjie; He, Yumin; Chen, Xuefeng; Zhai, Zhi; Wang, Youming; He, Zhengjia

    2010-02-01

    In this paper, a new method is presented to identify crack location and size, which is based on stress intensity factor suitable for pipe structure and finite element method of second generation wavelets (SGW-FEM). Pipe structure is dispersed into a series of nested thin-walled pipes. By making use of stress intensity factor of the thin-walled pipe, a new calculation method of crack equivalent stiffness is proposed to solve the stress intensity factor of the pipe structure. On this basis, finite element method of second generation wavelets is used to establish the dynamic model of cracked pipe. Then we combine forward problem with inverse problem in order to establish quantitative identification method of the crack based on frequency change, which provides a non-destructive testing technology with vibration for the pipe structure. The efficiency of the proposed method is verified by experiments.

  18. Heterogeneity in Short Gamma-Ray Bursts

    NASA Technical Reports Server (NTRS)

    Norris, Jay P.; Gehrels Neil; Scargle, Jeffrey D.

    2011-01-01

    We analyze the Swift/BAT sample of short gamma-ray bursts, using an objective Bayesian Block procedure to extract temporal descriptors of the bursts' initial pulse complexes (IPCs). The sample comprises 12 and 41 bursts with and without extended emission (EE) components, respectively. IPCs of non-EE bursts are dominated by single pulse structures, while EE bursts tend to have two or more pulse structures. The medians of characteristic timescales - durations, pulse structure widths, and peak intervals - for EE bursts are factors of approx 2-3 longer than for non-EE bursts. A trend previously reported by Hakkila and colleagues unifying long and short bursts - the anti-correlation of pulse intensity and width - continues in the two short burst groups, with non-EE bursts extending to more intense, narrower pulses. In addition we find that preceding and succeeding pulse intensities are anti-correlated with pulse interval. We also examine the short burst X-ray afterglows as observed by the Swift/XRT. The median flux of the initial XRT detections for EE bursts (approx 6 X 10(exp -10) erg / sq cm/ s) is approx > 20 x brighter than for non-EE bursts, and the median X-ray afterglow duration for EE bursts (approx 60,000 s) is approx 30 x longer than for non-EE bursts. The tendency for EE bursts toward longer prompt-emission timescales and higher initial X-ray afterglow fluxes implies larger energy injections powering the afterglows. The longer-lasting X-ray afterglows of EE bursts may suggest that a significant fraction explode into more dense environments than non-EE bursts, or that the sometimes-dominant EE component efficiently p()wers the afterglow. Combined, these results favor different progenitors for EE and non-EE short bursts.

  19. Explosive Welding of Pipes

    NASA Astrophysics Data System (ADS)

    Burtseva, Olga

    2007-06-01

    For connection by welding it is suggested to use the explosive welding method. This method is rather new. Nevertheless, it has become commonly used among the technological developments. This method can be advantageous (saving material and physical resources) comparing to its statical analogs (electron-beam welding, argon-arc welding, plasma welding, gas welding, etc.), in particular, in hard-to-reach areas due to their geographic and climatic conditions. The suggestion is to use water as filler. The principle of non-compressibility of liquid under quasi-dynamic loading is used. In one-dimensional gasdynamic and elastic-plastic calculations we determined non-deformed mass of water (perturbations, which are moving in the axial direction with sound velocity, should not reach the layer end boundaries for 5-7 circulations of shock waves in the radial direction). Linear dimension of the water layer from the zone of pipe coupling along axis in each direction is >= 2R, where R is the internal radius of pipe. Model experiments with pipes having radii R = 57 mm confirmed results of the calculations and the possibility in principle to weld pipes by explosion with use of water as filler. Reduction of pipe diameter after dynamic loading and explosive welding was ˜2%.

  20. Wedgethread pipe connection

    DOEpatents

    Watts, John D.

    2003-06-17

    Several embodiments of a wedgethread pipe connection are disclosed that have improved makeup, sealing, and non-loosening characteristics. In one embodiment, an open wedgethread is disclosed that has an included angle measured in the gap between the stab flank and the load flank to be not less than zero, so as to prevent premature wedging between mating flanks before the position of full makeup is reached, as does occur between trapped wedgethreads wherein the included angle is less than zero. The invention may be used for pipe threads large or small, as a flush joint, with collars, screwed into plates or it may even be used to reversibly connect such as solid posts to base members where a wide makeup torque range is desired. This Open wedgethread, as opposed to trapped wedgethreads, provides a threaded pipe connection that: is more cost-effective; can seal high pressure gas; can provide selectively a connection strength as high as the pipe strength; assures easy makeup to the desired position of full makeup within a wide torque range; may have a torque strength as high as the pipe torque strength; is easier to manufacture; is easier to gage; and is less subject to handling damage.

  1. Remotely operated pipe connector

    DOEpatents

    Josefiak, Leonard J.; Cramer, Charles E.

    1988-01-01

    An apparatus for remotely assembling and disassembling a Graylock type coctor between a pipe and a closure for the pipe includes a base and a receptacle on the base for the closure. The pipe is moved into position vertically above the closure by a suitable positioning device such that the flange on the pipe is immediately adjacent and concentric with the flange on the closure. A moving device then moves two semicircular collars from a position free of the closure to a position such that the interior cam groove of each collar contacts the two flanges. Finally, a tensioning device automatically allows remote tightening and loosening of a nut and bolt assembly on each side of the collar to cause a seal ring located between the flanges to be compressed and to seal the closure. Release of the pipe and the connector is accomplished in the reverse order. Preferably, the nut and bolt assembly includes an elongate shaft portion on which a removable sleeve is located.

  2. Comet Bursting Through Relaxation

    NASA Astrophysics Data System (ADS)

    Jacobson, Seth A.; Scheeres, D. J.

    2012-10-01

    Comets may be excited and occupy non-principal axis (complex) rotation states for a large fraction of their lifetimes. Many comet nuclei have been identified or are suspected to occupy non-principal axis (complex) rotation [Belton 2005, etc.] as well as have evolving rotation rates [Belton 2011, etc.]. Comet orbits drive these rotation states through cycles of excitation due to surface jets and relaxation due to time variable internal stresses that dissipate energy in the anelastic comet interior. Furthermore, relaxation from complex rotation can increase the loads along the symmetry axis of prolate comets. These loads stretch the body along the symmetry axis and may be the cause of the characteristic ``bowling pin’’ shape and eventually may lead to failure. This is an alternative model for comet bursting. Each cycle deposits only a small amount of energy and stress along the axis, but this process is repeated every orbit during which jets are activated. Our model for the evolution of comet nuclei includes torques due to a number of discrete jets located on the surface based on Neishtadt et al. [2002]. The model also includes internal dissipation using an approach developed by Sharma et al. [2005] and Vokrouhlicky et al. [2009]. These equations are averaged over the instantaneous spin state and the heliocentric orbit so the long-term evolution of the comet can be determined. We determine that even after the inclusion of internal dissipation there still exist non-principal axis equilibrium states for certain jet geometries. For ranges of dissipation factors and jet geometries, prolate comets are found to occupy states that have time variable internal loads over long time periods. These periodic loadings along the symmetry axis may lead to ``necking’’ as the body extends along the axis to release the stress and eventually disruption.

  3. Sparsity based defect imaging in pipes using guided waves

    NASA Astrophysics Data System (ADS)

    Golato, Andrew; Santhanam, Sridhar; Ahmad, Fauzia; Amin, Moeness G.

    2016-05-01

    Pipes are used for the transport of fluids and gases in urban and industrial settings, such as buried pipelines to transport water, oil, and other resources. To ensure reliable operation, it is essential that an inspection system be in place to identify and localize damage/defects in the pipes. Unfortunately, many of the typical nondestructive evaluation techniques are inadequate due to limited pipe access; often, only the beginning and end sections of the pipe are physically accessible. As such, this problem is well suited to the use of ultrasonic guided-wave based structural health monitoring. With a limited number of transducers, ultrasonic guided waves can be used to interrogate long lengths of pipes. In this paper, we propose a damage detection and localization scheme that relies upon the inherent sparsity of defects in the pipes. A sparse array of transducers, deployed in accessible areas of the pipes, is utilized in pitch-catch mode to record signals scattered by defects in the pipe. Both the direct path scattering off the defect, and the helical modes, which are paths that spiral around the circumference of the pipe before or after interaction with the defect, are recorded. A Lamb wave based signal model is formulated that accounts for this multipath approach. The signal model is then inverted via group sparse reconstruction, in order to produce an image of the scene. The model accounts for the specificities of Lamb wave propagation through the pipe. Performance validation of the proposed approach is provided using simulated data for an aluminum pipe.

  4. Heat Pipe Technology

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The heat pipe, a sealed chamber whose walls are lined with a "wick," a thin capillary network containing a working fluid in liquid form was developed for a heat distribution system for non-rotating satellites. Use of the heat pipe provides a continuous heat transfer mechanism. "Heat tubes" that improve temperature control in plastics manufacturing equipment incorporated the heat pipe technology. James M. Stewart, an independent consultant, patented the heat tubes he developed and granted a license to Kona Corporation. The Kona Nozzle for heaterless injection molding gets heat for its operation from an external source and has no internal heating bands, reducing machine maintenance and also eliminating electrical hazards associated with heater bands. The nozzles are used by Eastman Kodak, Bic Pen Corporation, Polaroid, Tupperware, Ford Motor Company, RCA, and Western Electric in the molding of their products.

  5. Apparatus for inspecting piping

    DOEpatents

    Zollingger, W.T.; Appel, D.K.; Park, L.R.

    1995-03-21

    An inspection rabbit is described for inspecting piping systems having severe bends therein. The rabbit consists of a flexible, modular body containing a miniaturized eddy current inspection probe, a self-contained power supply for proper operation of the rabbit, an outer surface that allows ease of movement through piping systems and means for transmitting data generated by the inspection device. The body is preferably made of flexible polyvinyl chloride (PVC) tubing or, alternatively, silicone rubber with a shrink wrapping of polytetrafluoroethylene (TEFLON{trademark}). The body is formed to contain the power supply, preferably a plurality of batteries, and a spool of communication wire that connects to a data processing computer external to the piping system. 6 figures.

  6. Apparatus for inspecting piping

    DOEpatents

    Zollingger, W. Thor; Appel, D. Keith; Park, Larry R.

    1995-01-01

    An inspection rabbit for inspecting piping systems having severe bends therein. The rabbit consists of a flexible, modular body containing a miniaturized eddy current inspection probe, a self-contained power supply for proper operation of the rabbit, an outer surface that allows ease of movement through piping systems and means for transmitting data generated by the inspection device. The body is preferably made of flexible polyvinyl chloride (PVC) tubing or, alternatively, silicone rubber with a shrink wrapping of polytetrafluoroethylene (TEFLON.RTM.). The body is formed to contain the power supply, preferably a plurality of batteries, and a spool of communication wire that connects to a data processing computer external to the piping system.

  7. Heat-pipe Earth.

    PubMed

    Moore, William B; Webb, A Alexander G

    2013-09-26

    The heat transport and lithospheric dynamics of early Earth are currently explained by plate tectonic and vertical tectonic models, but these do not offer a global synthesis consistent with the geologic record. Here we use numerical simulations and comparison with the geologic record to explore a heat-pipe model in which volcanism dominates surface heat transport. These simulations indicate that a cold and thick lithosphere developed as a result of frequent volcanic eruptions that advected surface materials downwards. Declining heat sources over time led to an abrupt transition to plate tectonics. Consistent with model predictions, the geologic record shows rapid volcanic resurfacing, contractional deformation, a low geothermal gradient across the bulk of the lithosphere and a rapid decrease in heat-pipe volcanism after initiation of plate tectonics. The heat-pipe Earth model therefore offers a coherent geodynamic framework in which to explore the evolution of our planet before the onset of plate tectonics. PMID:24067709

  8. Composite drill pipe

    DOEpatents

    Leslie, James C.; Leslie, II, James C.; Heard, James; Truong, Liem , Josephson; Marvin , Neubert; Hans

    2008-12-02

    A composite pipe segment is formed to include tapered in wall thickness ends that are each defined by opposed frustoconical surfaces conformed for self centering receipt and intimate bonding contact within an annular space between corresponding surfaces of a coaxially nested set of metal end pieces. The distal peripheries of the nested end pieces are then welded to each other and the sandwiched and bonded portions are radially pinned. The composite segment may include imbedded conductive leads and the axial end portions of the end pieces are shaped to form a threaded joint with the next pipe assembly that includes a contact ring in one pipe assembly pierced by a pointed contact in the other to connect the corresponding leads across the joint.

  9. Heat pipes and use of heat pipes in furnace exhaust

    SciTech Connect

    Polcyn, Adam D.

    2010-12-28

    An array of a plurality of heat pipe are mounted in spaced relationship to one another with the hot end of the heat pipes in a heated environment, e.g. the exhaust flue of a furnace, and the cold end outside the furnace. Heat conversion equipment is connected to the cold end of the heat pipes.

  10. Apparatus for moving a pipe inspection probe through piping

    DOEpatents

    Zollinger, W.T.; Appel, D.K.; Lewis, G.W.

    1995-07-18

    A method and apparatus are disclosed for controllably moving devices for cleaning or inspection through piping systems, including piping systems with numerous piping bends therein, by using hydrostatic pressure of a working fluid introduced into the piping system. The apparatus comprises a reservoir or other source for supplying the working fluid to the piping system, a launch tube for admitting the device into the launcher and a reversible, positive displacement pump for controlling the direction and flow rate of the working fluid. The device introduced into the piping system moves with the flow of the working fluid through the piping system. The launcher attaches to the valved ends of a piping system so that fluids in the piping system can recirculate in a closed loop. The method comprises attaching the launcher to the piping system, supplying the launcher with working fluid, admitting the device into the launcher, pumping the working fluid in the direction and at the rate desired so that the device moves through the piping system for pipe cleaning or inspection, removing the device from the launcher, and collecting the working fluid contained in the launcher. 8 figs.

  11. Apparatus for moving a pipe inspection probe through piping

    DOEpatents

    Zollinger, W. Thor; Appel, D. Keith; Lewis, Gregory W.

    1995-01-01

    A method and apparatus for controllably moving devices for cleaning or inspection through piping systems, including piping systems with numerous piping bends therein, by using hydrostatic pressure of a working fluid introduced into the piping system. The apparatus comprises a reservoir or other source for supplying the working fluid to the piping system, a launch tube for admitting the device into the launcher and a reversible, positive displacement pump for controlling the direction and flow rate of the working fluid. The device introduced into the piping system moves with the flow of the working fluid through the piping system. The launcher attaches to the valved ends of a piping system so that fluids in the piping system can recirculate in a closed loop. The method comprises attaching the launcher to the piping system, supplying the launcher with working fluid, admitting the device into the launcher, pumping the working fluid in the direction and at the rate desired so that the device moves through the piping system for pipe cleaning or inspection, removing the device from the launcher, and collecting the working fluid contained in the launcher.

  12. Excitation and Scattering of Guided WAVES—RELATIONSHIPS Between Solutions for Plates and Pipes

    NASA Astrophysics Data System (ADS)

    Velichko, A.; Wilcox, P. D.

    2008-02-01

    In many important industrial applications the diameter of a pipe is much larger than wall thickness. In this case the approximate theory is applicable, when a pipe is considered as an unwrapped isotropic plate. In this paper, a technique for obtaining pipe mode amplitudes in terms of the solution to the forced 3D problem on a plate is presented. The same principle can be extended to relate guided wave scattering from defects in plates to scattered circumferential modal amplitudes from defects in pipe. Results are shown that illustrate the application of the method to reflection from through thickness circumferential cracks in pipes.

  13. A Novel Pre-cooling System for a Cryogenic Pulsating Heat Pipe

    NASA Astrophysics Data System (ADS)

    Xu, Dong; Liu, Huiming; Gong, Linghui; Xu, Xiangdong; Li, Laifeng

    To reduce the influence of the pipe material on the measurement of effective thermal conductivity, the pipe of a cryogenic pulsating heat pipe is generally made of stainless steel. Because of the low thermal conductivity of stainless steel, the pre-cooling of the evaporator in cryogenic pulsating heat pipe using helium as working fluid at 4.2 K is a problem. We designed a mechanical-thermal switch between the cryocooler and the evaporator, which was on during the pre-cooling process and off during the test process. By using the pre-cooling system, the cool down time of the cryogenic pulsating heat pipe was reduced significantly.

  14. Superfluid Helium Heat Pipe

    NASA Astrophysics Data System (ADS)

    Gully, P.

    This paper reports on the development and the thermal tests of three superfluid helium heat pipes. Two of them are designed to provide a large transport capacity (4 mW at 1.7 K). They feature a copper braid located inside a 6 mm outer diameter stainless tube fitted with copper ends for mechanical anchoring. The other heat pipe has no copper braid and is designed to get much smaller heat transport capacity (0.5 mW) and to explore lower temperature (0.7 - 1 K). The copper braid and the tube wall is the support of the Rollin superfluid helium film in which the heat is transferred. The low filling pressure makes the technology very simple with the possibility to easily bend the tube. We present the design and discuss the thermal performance of the heat pipes tested in the 0.7 to 2.0 K temperature range. The long heat pipe (1.2 m with copper braid) and the short one (0.25 m with copper braid) have similar thermal performance in the range 0.7 - 2.0 K. At 1.7 K the long heat pipe, 120 g in weight, reaches a heat transfer capacity of 6.2 mW and a thermal conductance of 600 mW/K for 4 mW transferred power. Due to the pressure drop of the vapor flow and Kapitza thermal resistance, the conductance of the third heat pipe dramatically decreases when the temperature decreases. A 3.8 mW/K is obtained at 0.7 K for 0.5 mW transferred power.

  15. Heat pipe array heat exchanger

    DOEpatents

    Reimann, Robert C.

    1987-08-25

    A heat pipe arrangement for exchanging heat between two different temperature fluids. The heat pipe arrangement is in a ounterflow relationship to increase the efficiency of the coupling of the heat from a heat source to a heat sink.

  16. Heat transfer in pipes

    NASA Technical Reports Server (NTRS)

    Burbach, T.

    1985-01-01

    The heat transfer from hot water to a cold copper pipe in laminar and turbulent flow condition is determined. The mean flow through velocity in the pipe, relative test length and initial temperature in the vessel were varied extensively during tests. Measurements confirm Nusselt's theory for large test lengths in laminar range. A new equation is derived for heat transfer for large starting lengths which agrees satisfactorily with measurements for large starting lengths. Test results are compared with the new Prandtl equation for heat transfer and correlated well. Test material for 200- and to 400-diameter test length is represented at four different vessel temperatures.

  17. Heat pipe cooled probe

    NASA Technical Reports Server (NTRS)

    Camarda, C. J. (Inventor); Couch, L. M.

    1984-01-01

    The basic heat pipe principle is employed to provide a self-contained passively cooled probe that may be placed into a high temperature environment. The probe consists of an evaporator region of a heat pipe and a sensing instrument. Heat is absorbed as the working fluid evaporates in the probe. The vapor is transported to the vapor space of the condenser region. Heat is dissipated from the condenser region and fins causing condensation of the working fluid, which returns to the probe by gravity and the capillary action of the wick. Working fluid, wick and condenser configurations and structure materials can be selected to maintain the probe within an acceptable temperature range.

  18. Analysis of Q burst waveforms

    NASA Astrophysics Data System (ADS)

    Ogawa, Toshio; Komatsu, Masayuki

    2007-04-01

    The electric field changes in ELF to VLF were observed with a ball antenna in fair weather at Kochi (latitude 33.3°N, longitude 133.4°E) during 2003-2004. Some 376 Q bursts were obtained, seven examples of which are analyzed in the present study. The continuous frequency spectra of the Q bursts and the background noises from 1.0 Hz to 11 kHz are compared, and it was found that the Q bursts prevail over the background in the frequency range from 1 to 300 Hz. The surplus is 20 dB (in amplitude) near the fundamental mode frequency. The "W"-type changes found in the initial portion of the Q burst waveforms are interpreted as the combined electromagnetic waveform of direct and antipodal waves from the causative lightning strokes. From the time intervals between the two waves, the source-receiver distances are estimated as far as 19 Mm. The pulses to excite the Schumann resonances in the Q bursts are clearly identified.

  19. Mechanism for fast radio bursts

    NASA Astrophysics Data System (ADS)

    Romero, G. E.; del Valle, M. V.; Vieyro, F. L.

    2016-01-01

    Fast radio bursts are mysterious transient sources likely located at cosmological distances. The derived brightness temperatures exceed by many orders of magnitude the self-absorption limit of incoherent synchrotron radiation, implying the operation of a coherent emission process. We propose a radiation mechanism for fast radio bursts where the emission arises from collisionless bremsstrahlung in strong plasma turbulence excited by relativistic electron beams. We discuss possible astrophysical scenarios in which this process might operate. The emitting region is a turbulent plasma hit by a relativistic jet, where Langmuir plasma waves produce a concentration of intense electrostatic soliton-like regions (cavitons). The resulting radiation is coherent and, under some physical conditions, can be polarized and have a power-law distribution in energy. We obtain radio luminosities in agreement with the inferred values for fast radio bursts. The time scale of the radio flare in some cases can be extremely fast, of the order of 1 0-3 s . The mechanism we present here can explain the main features of fast radio bursts and is plausible in different astrophysical sources, such as gamma-ray bursts and some active galactic nuclei.

  20. Pipe Drafting with CAD. Teacher Edition.

    ERIC Educational Resources Information Center

    Smithson, Buddy

    This teacher's guide contains nine units of instruction for a course on computer-assisted pipe drafting. The course covers the following topics: introduction to pipe drafting with CAD (computer-assisted design); flow diagrams; pipe and pipe components; valves; piping plans and elevations; isometrics; equipment fabrication drawings; piping design…

  1. Burst Fractures as a Result of Attempted Suicide by Jumping

    PubMed Central

    Kim, Do Young; Park, Jeong Yoon; Kim, Kyung Hyun; Kuh, Sung Uk; Chin, Dong Kyu; Kim, Keun Su; Cho, Yong Eun; Jin, Byoung Ho

    2014-01-01

    Objective Jumping from high place for the purpose of suicide results in various damages to body area. A burst fracture of vertebrae is representative of them and we reviewed eight patients who were diagnosed with spinal burst fracture following suicide falling-down. The demographics, characteristics, performed operation, combined injuries, psychological past histories of the patients were analyzed. Methods A retrospective study was made of patients who are diagnosed with vertebral burst fracture from falling-down with the purpose of suicide admitted to department of neurosurgery of the author's hospital, covering the period between 2003 and 2012. Results Total eight patients were suicidal jumper. There were eleven vertebral burst fractures in eight patients and mean age was 26.5 years old. Seven patients already had psychological past history and there were various combined injuries except vertebrae burst fracture. The ankle fracture such as calcaneus, talus, navicular and malleolus was the most common injury and there were also various combined injury. Conclusion Suicidal jumper is different from incidental faller in some aspects because of different injury mechanism. For managing suicidal jumper, physician had to consider patients' age, affected site, psychiatric problem and combined injuries. Each department related to the injuries of patient have to cooperate each other with departments of psychiatry and rehabilitation from beginning to end. PMID:27169037

  2. Deployable heat-pipe radiator

    NASA Technical Reports Server (NTRS)

    Edelstein, F.

    1978-01-01

    Loop temperatures are controlled effectively under varying load conditions. Radiator has four separate pieces of hardware: heat-pipe panel, flexible heat-pipe leader, heat exchanger, fluid header. Single-fluid transport capacities of about 850 watts, corresponding to 51,000 watt-inches, have been achieved in 90 degree bend orientation of heat-pipe header.

  3. Reusable high-temperature heat pipes and heat pipe panels

    NASA Technical Reports Server (NTRS)

    Camarda, Charles J. (Inventor); Ransone, Philip O. (Inventor)

    1989-01-01

    A reusable, durable heat pipe which is capable of operating at temperatures up to about 3000 F in an oxidizing environment and at temperatures above 3000 F in an inert or vacuum environment is produced by embedding a refractory metal pipe within a carbon-carbon composite structure. A reusable, durable heat pipe panel is made from an array of refractory-metal pipes spaced from each other. The reusable, durable, heat-pipe is employed to fabricate a hypersonic vehicle leading edge and nose cap.

  4. Using ductile iron pipe for penstocks: A new option

    SciTech Connect

    Hurless, R.C.

    1996-04-01

    When choosing the type of material for the penstock at a new project or when repairing or replacing pipe at existing plants, it may pay off to take a look at ductile iron pipe. This type of pipe was used at the Wailuku River hydro project, resulting in a more corrosion resistant, durable, and cost-effective penstock. This article reviews the planning and decision-making that went into this effort, including: (1) material properties, (2) testing, (3) performance under negative pressure conditions, (4) pressure rating, (5) corrosion resistance, (6) seismic effects, (7) installation problems, and (8) economic considerations.

  5. Bursts in discontinuous Aeolian saltation

    PubMed Central

    Carneiro, M. V.; Rasmussen, K. R.; Herrmann, H. J.

    2015-01-01

    Close to the onset of Aeolian particle transport through saltation we find in wind tunnel experiments a regime of discontinuous flux characterized by bursts of activity. Scaling laws are observed in the time delay between each burst and in the measurements of the wind fluctuations at the fluid threshold Shields number θc. The time delay between each burst decreases on average with the increase of the Shields number until sand flux becomes continuous. A numerical model for saltation including the wind-entrainment from the turbulent fluctuations can reproduce these observations and gives insight about their origin. We present here also for the first time measurements showing that with feeding it becomes possible to sustain discontinuous flux even below the fluid threshold. PMID:26073305

  6. Chimera states in bursting neurons

    NASA Astrophysics Data System (ADS)

    Bera, Bidesh K.; Ghosh, Dibakar; Lakshmanan, M.

    2016-01-01

    We study the existence of chimera states in pulse-coupled networks of bursting Hindmarsh-Rose neurons with nonlocal, global, and local (nearest neighbor) couplings. Through a linear stability analysis, we discuss the behavior of the stability function in the incoherent (i.e., disorder), coherent, chimera, and multichimera states. Surprisingly, we find that chimera and multichimera states occur even using local nearest neighbor interaction in a network of identical bursting neurons alone. This is in contrast with the existence of chimera states in populations of nonlocally or globally coupled oscillators. A chemical synaptic coupling function is used which plays a key role in the emergence of chimera states in bursting neurons. The existence of chimera, multichimera, coherent, and disordered states is confirmed by means of the recently introduced statistical measures and mean phase velocity.

  7. Bursts in discontinuous Aeolian saltation.

    PubMed

    Carneiro, M V; Rasmussen, K R; Herrmann, H J

    2015-01-01

    Close to the onset of Aeolian particle transport through saltation we find in wind tunnel experiments a regime of discontinuous flux characterized by bursts of activity. Scaling laws are observed in the time delay between each burst and in the measurements of the wind fluctuations at the fluid threshold Shields number θc. The time delay between each burst decreases on average with the increase of the Shields number until sand flux becomes continuous. A numerical model for saltation including the wind-entrainment from the turbulent fluctuations can reproduce these observations and gives insight about their origin. We present here also for the first time measurements showing that with feeding it becomes possible to sustain discontinuous flux even below the fluid threshold. PMID:26073305

  8. Defect characterization in pipe-to-pipe welds in large diameter stainless steel piping

    SciTech Connect

    Rawl, D.E. Jr.; West, S.L.; Wheeler, D.A.; Louthan, M.R. Jr.

    1990-01-01

    Metallurgical evaluation of pipe-to-pipe welds in large-diameter, Type 304 stainless steel piping used to construct the moderator/coolant water systems for Savannah River Site reactors has demonstrated that small weld defects found in this 1950-vintage system do not compromise the integrity of the system. The weld defects were too small for detection by the pre-service standard radiographic inspection, but were found through systematic ultrasonic testing (UT) and penetrant testing (PT) evaluations of piping that had been removed during upgrades to the piping system. The defects include lack of weld penetration, slag inclusions, and other weld metal discontinuities. These discontinuities typically did not propagate during more than 35 years of service. The defects examined were too small and isolated to degrade the mechanical properties of the pipe-to-pipe weldments and therefore did not compromise the integrity of the piping system. 14 refs., 7 figs.

  9. 46 CFR 154.503 - Piping and piping system components: Protection from movement.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Piping and piping system components: Protection from..., Construction and Equipment Cargo and Process Piping Systems § 154.503 Piping and piping system components... cause stresses that exceed the design stresses, the piping and piping system components and cargo...

  10. 46 CFR 154.503 - Piping and piping system components: Protection from movement.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Piping and piping system components: Protection from..., Construction and Equipment Cargo and Process Piping Systems § 154.503 Piping and piping system components... cause stresses that exceed the design stresses, the piping and piping system components and cargo...

  11. 46 CFR 154.503 - Piping and piping system components: Protection from movement.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Piping and piping system components: Protection from..., Construction and Equipment Cargo and Process Piping Systems § 154.503 Piping and piping system components... cause stresses that exceed the design stresses, the piping and piping system components and cargo...

  12. 46 CFR 154.503 - Piping and piping system components: Protection from movement.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Piping and piping system components: Protection from..., Construction and Equipment Cargo and Process Piping Systems § 154.503 Piping and piping system components... cause stresses that exceed the design stresses, the piping and piping system components and cargo...

  13. DECIMETRIC TYPE III BURSTS: GENERATION AND PROPAGATION

    SciTech Connect

    Li, B.; Cairns, Iver H.; Robinson, P. A.; Yan, Y. H.

    2011-09-01

    Simulations are presented for decimetric type III radio bursts at 2f{sub p} , where f{sub p} is the local electron plasma frequency. The simulations show that 2f{sub p} radiation can be observed at Earth in two scenarios for the radiation's generation and propagation. In Scenario A, radiation is produced and propagates in warm plasmas in the lower corona that are caused by previous magnetic reconnection outflows and/or chromospheric evaporation. In Scenario B radiation is generated in normal plasmas, then due to its natural directivity pattern and refraction, radiation partly propagates into nearby regions, which are hot because of previous reconnection/evaporation. The profiles of plasma density n{sub e} (r) and electron temperature T{sub e} (r) in the lower corona (r - R{sub sun} {approx}< 100 Mm) are found to be crucial to whether radiation can be produced and escape at observable levels against the effects of free-free absorption, where r is the heliocentric distance. Significantly, the observed wide ranges of radiation properties (e.g., drift rates) require n{sub e} (r) with a large range of scale heights h{sub s} , consistent nonetheless for Scenario B with short observed EUV loops. This is relevant to problems with large h{sub s} inferred from tall EUV loops. The simulations suggest: (1) n{sub e} (r) with small h{sub s} , such as n{sub e} (r){proportional_to}(r - R{sub sun}){sup -2.38} for flaring regions, are unexpectedly common deep in the corona. This result is consistent with recent work on n{sub e} (r) for r {approx} (1.05-2)R{sub sun} extracted from observed metric type IIIs. (2) The dominance of reverse-slope bursts over normal bursts sometimes observed may originate from asymmetric reconnection/acceleration, which favors downgoing beams.

  14. Explosive Welding of Pipes

    NASA Astrophysics Data System (ADS)

    Drennov, Oleg; Drennov, Andrey; Burtseva, Olga

    2013-06-01

    For connection by welding it is suggested to use the explosive welding method. This method is rather new. Nevertheless, it has become commonly used among the technological developments. This method can be advantageous (saving material and physical resources) comparing to its statical analogs (electron-beam welding, argon-arc welding, plasma welding, gas welding, etc.), in particular, in hard-to-reach areas due to their geographic and climatic conditions. Explosive welding of cylindrical surfaces is performed by launching of welded layer along longitudinal axis of construction. During this procedure, it is required to provide reliable resistance against radial convergent strains. The traditional method is application of fillers of pipe cavity, which are dense cylindrical objects having special designs. However, when connecting pipes consecutively in pipelines by explosive welding, removal of the fillers becomes difficult and sometimes impossible. The suggestion is to use water as filler. The principle of non-compressibility of liquid under quasi-dynamic loading is used. In one-dimensional gasdynamic and elastic-plastic calculations we determined non-deformed mass of water (perturbations, which are moving in the axial direction with sound velocity, should not reach the layer end boundaries for 5-7 circulations of shock waves in the radial direction). Linear dimension of the water layer from the zone of pipe coupling along axis in each direction is >= 2R, where R is the internal radius of pipe.

  15. Flexible Heat Pipe

    NASA Technical Reports Server (NTRS)

    Bienert, W. B.; Wolf, D. A.

    1985-01-01

    Narrow Tube carries 10 watts or more to moving parts. Heat pipe 12 inches long and diameter of 0.312 inch (7.92mm). Bent to minimum radius of 2.5 blocks. Flexible section made of 321 stainless steel tubing (Cajon Flexible Tubing or equivalent). Evaporator and condenser made of oxygen free copper. Working fluid methanol.

  16. Aeronautical tubes and pipes

    NASA Astrophysics Data System (ADS)

    Beauclair, N.

    1984-12-01

    The main and subcomponent French suppliers of aircraft tubes and pipes are discussed, and the state of the industry is analyzed. Quality control is essential for tubes with regard to their i.d. and metallurgical compositions. French regulations do not allow welded seam tubes in hydraulic circuits unless no other form is available, and then rustproofed steel must be installed. The actual low level of orders for any run of tubes dictates that the product is only one of several among the manufacturers' line. Automation, both in NDT and quality control, assures that the tubes meet specifications. A total of 10 French companies participate in the industry, serving both civil and military needs, with some companies specializing only in titanium, steel, or aluminum materials. Concerns wishing to enter the market must upgrade their equipment to meet the higher aeronautical specifications and be prepared to furnish tubes and pipes that serve both functional and structural purposes simultaneously. Additionally, pipe-bending machines must also perform to tight specifications. Pipes can range from 0.2 mm exterior diameter to 40 mm, with wall thicknesses from 0.02 mm to 3 mm. A chart containing a list of manufacturers and their respective specifications and characteristics is presented, and a downtrend in production with reduction of personnel is noted.

  17. Heat pipe investigations

    NASA Technical Reports Server (NTRS)

    Marshburn, J. P.

    1973-01-01

    Techniques associated with thermal-vacuum and bench testing, along with flight testing of the OAO-C spacecraft heat pipes are outlined, to show that the processes used in heat transfer design and testing are adequate for good performance evaluations.

  18. Heat Pipes Cool Power Magnetics

    NASA Technical Reports Server (NTRS)

    Hansen, I.; Chester, M.; Luedke, E.

    1983-01-01

    Configurations originally developed for space use are effective in any orientation. Heat pipes integrated into high-power, high-frequency, highvoltage spaceflight magnetics reduce weight and improve reliability by lowering internal tempertures. Two heat pipes integrated in design of power transformer cool unit in any orientation. Electrostatic shield conducts heat from windings to heat pipe evaporator. Technology allows dramatic reductions in size and weight, while significantly improving reliability. In addition, all attitude design of heat pipes allows operation of heat pipes independent of local gravity forces.

  19. Cosmology: Home of a fast radio burst

    NASA Astrophysics Data System (ADS)

    Lorimer, Duncan

    2016-02-01

    Our understanding of fast radio bursts -- intense pulses of radio waves -- and their use as cosmic probes promises to be transformed now that one burst has been associated with a galaxy of known distance from Earth. See Letter p.453

  20. Utilizing clad piping to improve process plant piping integrity, reliability, and operations

    SciTech Connect

    Chakravarti, B.

    1996-07-01

    During the past four years carbon steel piping clad with type 304L (UNS S30403) stainless steel has been used to solve the flow accelerated corrosion (FAC) problem in nuclear power plants with exceptional success. The product is designed to allow ``like for like`` replacement of damaged carbon steel components where the carbon steel remains the pressure boundary and type 304L (UNS S30403) stainless steel the corrosion allowance. More than 3000 feet of piping and 500 fittings in sizes from 6 to 36-in. NPS have been installed in the extraction steam and other lines of these power plants to improve reliability, eliminate inspection program, reduce O and M costs and provide operational benefits. This concept of utilizing clad piping in solving various corrosion problems in industrial and process plants by conservatively selecting a high alloy material as cladding can provide similar, significant benefits in controlling corrosion problems, minimizing maintenance cost, improving operation and reliability to control performance and risks in a highly cost effective manner. This paper will present various material combinations and applications that appear ideally suited for use of the clad piping components in process plants.

  1. On the problem of turbulent flows in pipes at very large Reynolds numbers (reply to comment by I I Vigdorovich [Phys. Usp. 58 196 (2015); Usp. Fiz. Nauk 185 213 (2015)] on "Turbulent flows at very large Reynolds numbers: new lessons learned" [Phys. Usp. 57 250 (2014); Usp. Fiz. Nauk 184 265 (2014)])

    NASA Astrophysics Data System (ADS)

    Barenblatt, G. I.; Chorin, A. J.; Prostokishin, V. M.

    2015-02-01

    The problem of turbulent flow in pipes, although at first sight of purely engineering interest, has since the 1930s been the subject of much attention by mathematicians and physicists, including such outstanding figures as Th von Kármán, L Prandtl, and L D Landau. It has turned out that despite - or perhaps due to - the seemingly simple formulation of this problem, research on it has revealed new aspects of the still very mysterious phenomenon of turbulence. Reference [1] briefly summarizes our work over the last twenty years on the problem. Some of our results strongly disagree with commonly accepted views which, unsurprisingly, makes them difficult to accept. This is well exemplified by letter [2], so its analysis here may hopefully be of interest to UFN's (Physics -Uspekhi) readers.

  2. A critical review of observations of classical gamma-ray bursts

    NASA Astrophysics Data System (ADS)

    Higdon, J. C.

    1996-04-01

    First, I discuss the evidence for spatial nonuniformity from burst experiments flown prior to CGRO. The range of deviations from spatial uniformity seem to be inconsistent with those expected from the corresponding range of instrumental sensitivities. After a discussion of how bursts are identified, I suggest that systematic errors, associated with burst selection criteria, are the likely source for the disparity among these experiments. Next, the statistically compelling (>~14σ) BATSE deviations from spatial uniformity are presented. I find that systematic effects are again important and present evidence that BATSE's on-board trigger is biased against the detection of both slow risers as well as rapid bursts. Such biases cause BATSE analyses to underestimate the actual of the bursts. Next, the classification of γ-ray transients are examined. I suggest that BATSE's qualitative, somewhat subjective, selection criteria can lead to problems in burst identification. Also, weak transients are more likely to be misidentified, and, consequently, the neglect of this bias produces a further small underestimation of the BATSE of the bursts. Next, I examine the important issue of BATSE location errors. Although such sky locations are consistent with isotropy, I suggest that the proper appreciation of systematics plays a pivotal role in interpreting such results. Then GINGA measurements of burst absorption features are presented. It seems very unlikely that such features result from statistical fluctuations, and I suggest that any discrepancy between BATSE's absence of line detections and GINGA detections resides with BATSE, not GINGA. The controversial report (71) of cosmological time dilation in BATSE bursts is addressed next. I find that unambiguous detection of such cosmological time dilation seems unlikely. Finally, I examine the reports (89,81) of evidence for classical bursts repetitions. I suggest that, if burst sources repeat infrequently (~2 yr-1

  3. Drill pipe protector development

    SciTech Connect

    Thomerson, C.; Kenne, R.; Wemple, R.P.

    1996-03-01

    The Geothermal Drilling Organization (GDO), formed in the early 1980s by the geothermal industry and the U.S. Department of Energy (DOE) Geothermal Division, sponsors specific development projects to advance the technologies used in geothermal exploration, drilling, and production phases. Individual GDO member companies can choose to participate in specific projects that are most beneficial to their industry segment. Sandia National Laboratories is the technical interface and contracting office for the DOE in these projects. Typical projects sponsored in the past have included a high temperature borehole televiewer, drill bits, muds/polymers, rotary head seals, and this project for drill pipe protectors. This report documents the development work of Regal International for high temperature geothermal pipe protectors.

  4. Explosive welding of pipes

    NASA Astrophysics Data System (ADS)

    Drennov, O.; Burtseva, O.; Kitin, A.

    2006-08-01

    For connection by welding it is suggested to use the explosive welding method. This method is rather new. Nevertheless, it has become commonly used among the technological developments. This method can be advantageous (saving material and physical resources) comparing to its statical analogs (electron-beam welding, argon-arc welding, plasma welding, gas welding, etc.), in particular, in hard-to-reach areas due to their geographic and climatic conditions. The suggestion is to use water as filler. The principle of non-compressibility of liquid under quasi-dynamic loading is used. In one-dimensional gasdynamic and elastic-plastic calculations we determined non-deformed mass of water. Model experiments with pipes having radii R = 57 mm confirmed results of the calculations and the possibility in principle to weld pipes by explosion with use of water as filler.

  5. Light Pipe Thermophotovoltaics (LTPV)

    NASA Astrophysics Data System (ADS)

    Chubb, Donald L.

    2007-02-01

    In a conventional thermophotovoltaic (TPV) energy converter the radiation from the emitter to the photovoltaic (PV) array is transmitted in a vacuum or air where the index of refraction, n = 1. The intensity of the radiation is proportional to n2. Therefore, the incident intensity on the PV array could be greatly increase if the medium between the emitter and the PV array had n > 1. This light pipe TPV (LTPV) concept was introduced by The Quantum Group at the Third National Renewable Energy Laboratory (NREL) TPV Conference in 1997. This paper presents a theoretical analysis of the LTPV concept. The solution of the one-dimensional energy equation that includes both thermal conduction and radiation yields the temperature distribution through the light pipe. Applying the analysis to a zinc selenide (ZnSe) light pipe yielded the following result. For an emitter temperature of 1000K the convertible radiation(photon energy >PV bandgap energy) that reaches the photovoltaic(PV) cell is 1 W/cm2. At the same emitter temperature, a conventional TPV converter would have 1/8 W/cm2 of convertible radiation. Thus, the LTPV concept makes possible lower temperature operation than current TPV converters.

  6. Guidable pipe plug

    DOEpatents

    Glassell, Richard L.; Babcock, Scott M.; Lewis, Benjamin E.

    2001-01-01

    A plugging device for closing an opening defined by an end of a pipe with sealant comprises a cap, an extension, an inner seal, a guide, and at least one stop. The cap has an inner surface which defines a chamber adapted for retaining the sealant. The chamber is dimensioned slightly larger than the end so as to receive the end. The chamber and end define a gap therebetween. The extension has a distal end and is attached to the inner surface opposite the distal end. The inner seal is attached to the extension and sized larger than the opening. The guide is positioned forward of the inner seal and attached to the distal end. The guide is also dimensioned to be inserted into the opening. The stop is attached to the extender, and when the stop is disposed in the pipe, the stop is movable with respect to the conduit in one direction and also prevents misalignment of the cap with the pipe. A handle can also be included to allow the cap to be positioned robotically.

  7. Observations of Gamma-Ray Bursts

    NASA Technical Reports Server (NTRS)

    Fishman, G. J.

    1995-01-01

    Some basic observed properties of gamma-ray bursts are reviewed. Although some properties were known 25 years ago, new and more detailed observations have been made by the Compton Observatory in the past three years. The new observation with the greatest impact has been the observed isotropic distribution of bursts along with a deficiency of weak bursts which would be expected from a homogeneous burst distribution. This is not compatible with any known Galactic population of objects. Gamma-ray bursts show an enormous variety of burst morphologies and a wide spread in burst durations. The spectra of gamma-ray bursts are characterized by rapid variations and peak power which is almost entirely in the gamma-ray energy range. Delayed gamma-ray burst photons extending to GeV energies have been detected for the first time. A time dilation effect has also been reported to be observed in gamma-ray, bursts. The observation of a gamma-ray burst counterpart in another wavelength region has yet to be made.

  8. Gamma-Ray Bursts: The End Game

    NASA Astrophysics Data System (ADS)

    Lamb, Don

    1997-11-01

    The nature of gamma-ray bursts has been one of the greatest unsolved mysteries in astrophysics for more than a quarter century. A major reason for this is that no definite counterparts to the bursts could be found at other wavelengths, despite intense efforts spanning more than two decades. Consequently, the study of gamma-ray bursts has been isolated from the rest of astronomy. Scientists studying them have had only the laws of physics and the bursts themselves to guide them in attempting to solve the burst mystery. All of this changed dramatically with the discovery earlier this year of fading X-ray and optical sources in the arcminute-sized positional error boxes of several gamma-ray bursts. For the first time, temporal, as well as spatial, coincidence could be used to associate these X-ray and optical sources with the gamma-ray bursts. As a result, the odds are great that the fading X-ray and optical sources are counterparts of the bursts, and that the study of gamma-ray bursts has finally been connected with the rest of astronomy. In this talk, we describe the dramatic new information about the nature of gamma-ray bursts that the X-ray, optical, and radio observations of the fading sources have provided, and emphasize the implications that this information has for the distance scale to the bursts.

  9. Emission model of gamma-ray bursts

    NASA Technical Reports Server (NTRS)

    Liang, E. P.

    1983-01-01

    The emission mechanisms of cosmic gamma-ray bursts are reviewed. In particular, the thermal synchrotron model is discussed as the most viable mechanism for the majority of the continuum emission. Within this framework various information about the source region can be extracted. The picture that emerges is that of a hot (kT = .2 - 1.0 sq mc), thin sheet of dense pair-dominated plasma emitting via cyclo-synchrotron radiation in a strong magnetic field (B approximately one-hundred billion to one trillion gauss). Speculations on the origin and structure of this sheet are attempted. The problem of high-energy photons above pair production threshold escaping from the source is also considered.

  10. Do gamma-ray burst sources repeat?

    NASA Technical Reports Server (NTRS)

    Meegan, Charles A.; Hartmann, Dieter H.; Brainerd, J. J.; Briggs, Michael S.; Paciesas, William S.; Pendleton, Geoffrey; Kouveliotou, Chryssa; Fishman, Gerald; Blumenthal, George; Brock, Martin

    1995-01-01

    The demonstration of repeated gamma-ray bursts from an individual source would severely constrain burst source models. Recent reports (Quashnock and Lamb, 1993; Wang and Lingenfelter, 1993) of evidence for repetition in the first BATSE burst catalog have generated renewed interest in this issue. Here, we analyze the angular distribution of 585 bursts of the second BATSE catalog (Meegan et al., 1994). We search for evidence of burst recurrence using the nearest and farthest neighbor statistic and the two-point angular correlation function. We find the data to be consistent with the hypothesis that burst sources do not repeat; however, a repeater fraction of up to about 20% of the observed bursts cannot be excluded.

  11. Spindle Bursts in Neonatal Rat Cerebral Cortex

    PubMed Central

    Yang, Jenq-Wei; Reyes-Puerta, Vicente; Kilb, Werner; Luhmann, Heiko J.

    2016-01-01

    Spontaneous and sensory evoked spindle bursts represent a functional hallmark of the developing cerebral cortex in vitro and in vivo. They have been observed in various neocortical areas of numerous species, including newborn rodents and preterm human infants. Spindle bursts are generated in complex neocortical-subcortical circuits involving in many cases the participation of motor brain regions. Together with early gamma oscillations, spindle bursts synchronize the activity of a local neuronal network organized in a cortical column. Disturbances in spindle burst activity during corticogenesis may contribute to disorders in cortical architecture and in the activity-dependent control of programmed cell death. In this review we discuss (i) the functional properties of spindle bursts, (ii) the mechanisms underlying their generation, (iii) the synchronous patterns and cortical networks associated with spindle bursts, and (iv) the physiological and pathophysiological role of spindle bursts during early cortical development. PMID:27034844

  12. Spindle Bursts in Neonatal Rat Cerebral Cortex.

    PubMed

    Yang, Jenq-Wei; Reyes-Puerta, Vicente; Kilb, Werner; Luhmann, Heiko J

    2016-01-01

    Spontaneous and sensory evoked spindle bursts represent a functional hallmark of the developing cerebral cortex in vitro and in vivo. They have been observed in various neocortical areas of numerous species, including newborn rodents and preterm human infants. Spindle bursts are generated in complex neocortical-subcortical circuits involving in many cases the participation of motor brain regions. Together with early gamma oscillations, spindle bursts synchronize the activity of a local neuronal network organized in a cortical column. Disturbances in spindle burst activity during corticogenesis may contribute to disorders in cortical architecture and in the activity-dependent control of programmed cell death. In this review we discuss (i) the functional properties of spindle bursts, (ii) the mechanisms underlying their generation, (iii) the synchronous patterns and cortical networks associated with spindle bursts, and (iv) the physiological and pathophysiological role of spindle bursts during early cortical development. PMID:27034844

  13. Procedures for measuring the properties of heat-pipe wick materials

    SciTech Connect

    Adkins, D.R.; Dykhuizen, R.C.

    1993-07-01

    Accurate measurements of wick properties must be available to design high-performance beat pipes and to properly interpret results from heat pipe tests. In a program that is aimed at developing heat-pipe receivers for solar-Stirling electric systems, we have recently explored procedures to measure the effective pore radius and permeability of wick materials in their final ``as fabricated`` condition. Measurement techniques are compared in this paper and problems that are frequently encountered in measuring wick properties are discussed.

  14. Heat pipe technology: A bibliography with abstracts

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The annual supplement on heat pipe technology for 1971 is presented. The document contains 101 references with abstracts and 47 patents. The subjects discussed are: (1) heat pipe applications, (2) heat pipe theory, (3) design, development, and fabrication of heat pipes, (4) testing and operation, (5) subject and author index, and (6) heat pipe related patents.

  15. Experimenting with a ``Pipe'' Whistle

    NASA Astrophysics Data System (ADS)

    Stafford, Olga

    2012-04-01

    A simple pipe whistle can be made using pieces of PVC pipe. The whistle can be used to measure the resonant frequencies of open or closed pipes. A slightly modified version of the device can be used to also investigate the interesting dependence of the sound frequencies produced on the orifice-to-edge distance. The pipe whistle described here allows students in a physics of music or introductory physics course to study an example of an "edge tone" device that produces discrete sound frequencies. From their textbooks, students likely know about standing waves produced by pipes or strings, as well as the resonant frequencies for open and closed pipes. To go a bit further, they can also learn how the frequency of the sound wave depends on the orifice-to-edge distance of the wind instrument.

  16. Detection of artifacts from high energy bursts in neonatal EEG.

    PubMed

    Bhattacharyya, Sourya; Biswas, Arunava; Mukherjee, Jayanta; Majumdar, Arun Kumar; Majumdar, Bandana; Mukherjee, Suchandra; Singh, Arun Kumar

    2013-11-01

    Detection of non-cerebral activities or artifacts, intermixed within the background EEG, is essential to discard them from subsequent pattern analysis. The problem is much harder in neonatal EEG, where the background EEG contains spikes, waves, and rapid fluctuations in amplitude and frequency. Existing artifact detection methods are mostly limited to detect only a subset of artifacts such as ocular, muscle or power line artifacts. Few methods integrate different modules, each for detection of one specific category of artifact. Furthermore, most of the reference approaches are implemented and tested on adult EEG recordings. Direct application of those methods on neonatal EEG causes performance deterioration, due to greater pattern variation and inherent complexity. A method for detection of a wide range of artifact categories in neonatal EEG is thus required. At the same time, the method should be specific enough to preserve the background EEG information. The current study describes a feature based classification approach to detect both repetitive (generated from ECG, EMG, pulse, respiration, etc.) and transient (generated from eye blinking, eye movement, patient movement, etc.) artifacts. It focuses on artifact detection within high energy burst patterns, instead of detecting artifacts within the complete background EEG with wide pattern variation. The objective is to find true burst patterns, which can later be used to identify the Burst-Suppression (BS) pattern, which is commonly observed during newborn seizure. Such selective artifact detection is proven to be more sensitive to artifacts and specific to bursts, compared to the existing artifact detection approaches applied on the complete background EEG. Several time domain, frequency domain, statistical features, and features generated by wavelet decomposition are analyzed to model the proposed bi-classification between burst and artifact segments. A feature selection method is also applied to select the

  17. Insulating Cryogenic Pipes With Frost

    NASA Technical Reports Server (NTRS)

    Stephenson, J. G.; Bova, J. A.

    1985-01-01

    Crystallized water vapor fills voids in pipe insulation. Small, carefully controlled amount of water vapor introduced into dry nitrogen gas before it enters aft fuselage. Vapor freezes on pipes, filling cracks in insulation. Ice prevents gaseous nitrogen from condensing on pipes and dripping on structure, in addition to helping to insulate all parts. Industrial applications include large refrigeration plants or facilities that use cryogenic liquids.

  18. Geometric analysis of transient bursts

    NASA Astrophysics Data System (ADS)

    Osinga, Hinke M.; Tsaneva-Atanasova, Krasimira T.

    2013-12-01

    We consider the effect of a brief stimulation from the rest state of a minimal neuronal model with multiple time scales. Such transient dynamics brings out the intrinsic bursting capabilities of the system. Our main goal is to show that a minimum of three dimensions is enough to generate spike-adding phenomena in transient responses, and that the onset of a new spike can be tracked using existing continuation packages. We take a geometric approach to illustrate how the underlying fast subsystem organises the spike adding in much the same way as for spike adding in periodic bursts, but the bifurcation analysis for spike onset is entirely different. By using a generic model, we further strengthen claims made in our earlier work that our numerical method for spike onset can be used for a broad class of systems.

  19. Flutter of articulated pipes at finite amplitude

    NASA Technical Reports Server (NTRS)

    Rousselet, J.; Herrmann, G.

    1977-01-01

    The plane motion of an articulated pipe made of two segments is examined and the flow velocity at which flutter manifests itself is sought. The pressure in the reservoir feeding the pipe is kept constant. In contrast to previous works, the flow velocity is not taken as a prescribed parameter of the system but is left to follow the laws of motion. This approach requires a nonlinear formulation of the problem and the equations of motion are solved using Krylov-Bogoliubov's method. A graph of the amplitude of the limit cycles, as a function of the fluid-system mass ratio, is presented and conclusions are drawn as to the necessity of considering nonlinearities in the analysis.

  20. Nonlinear gas oscillations in pipes. I - Theory.

    NASA Technical Reports Server (NTRS)

    Jimenez, J.

    1973-01-01

    The problem of forced acoustic oscillations in a pipe is studied theoretically. The oscillations are produced by a moving piston in one end of the pipe, while a variety of boundary conditions ranging from a completely closed to a completely open mouth at the other end are considered. The linear theory predicts large amplitudes near resonance and that nonlinear effects become crucially important. By expanding the equations of motion in a series in the Mach number, both the amplitude and waveform of the oscillation are predicted there. In both the open- and closed-end cases the need for shock waves in some range of parameters is found. The amplitude of the oscillation is different for the two cases, however, being proportional to the square root of the piston amplitude in the closed-end case and to the cube root for the open end.

  1. Thermostructural applications of heat pipes

    NASA Technical Reports Server (NTRS)

    Peeples, M. E.; Reeder, J. C.; Sontag, K. E.

    1979-01-01

    The feasibility of integrating heat pipes in high temperature structure to reduce local hot spot temperature was evaluated for a variety of hypersonic aerospace vehicles. From an initial list of twenty-two potential applications, the single stage to orbit wing leading edge showed the greatest promise and was selected for preliminary design of an integrated heat pipe thermostructural system. The design consisted of a Hastelloy X assembly with sodium heat pipe passages aligned normal to the wing leading edge. A d-shaped heat pipe cross section was determined to be optimum from the standpoint of structural weight.

  2. Cryogenic Heat Pipe Experiment (CRYOHP)

    NASA Technical Reports Server (NTRS)

    Mcintosh, Roy

    1992-01-01

    The objective of the CRYOHP experiment is to conduct a shuttle experiment that demonstrates the reliable operation of two oxygen heat pipes in microgravity. The experiment will perform the following tasks: (1) demonstrate startup of the pipes from the supercritical state; (2) measure the heat transport capacity of the pipes; (3) measure evaporator and condenser film coefficients; and (4) work shuttle safety issues. The approach for the experiment is as follows: (1) fly two axially grooved oxygen heat pipes attached to mechanical stirling cycle tactical coolers; (2) integrate experiment in hitch-hiker canister; and (3) fly on shuttle and control from ground.

  3. The application of PIV to the study of unsteady gas dynamic flow within pipes and at pipe discontinuities

    NASA Astrophysics Data System (ADS)

    Thornhill, D.; Fleck, R.; Li, H.; Woods, J.

    2007-10-01

    This paper describes research using a pulse generator that provides discrete waves. The wave motion was recorded using a series of high speed pressure transducers and the ensuing movement of the gas particles within the pipes was recorded using digital PIV. Gas particle velocities of up to 250m/s were a regular occurrence and vortices of high angular velocity were a common problem with associated spin out of seed particles. Although flows were predominantly two dimensional, stereoscopic techniques were used to give optical access to otherwise inaccessible areas of flow. So far these techniques have been applied to the unsteady gas dynamic flow within plain pipes, at sudden expansions and contractions within pipes and at the end of a pipe open to the environment, both plain ended and when fitted with a bellmouth. Examples of all of these are presented in this paper.

  4. Collapsed White Dwarfs as Gamma-Ray Burst Sources

    NASA Astrophysics Data System (ADS)

    de Paolis, F.; Ingrosso, G.; Qadir, A.

    1995-09-01

    It has been suggested by Usov (1992) that accreting white dwarfs, collapsing to neutron stars may be the sources of the gamma-ray bursts observed at cosmological distances, provided they rotate very fast and have enormously high magnetic fields. In this model the burst's durationτ is given by the ratio of pulsar kinetic energy and magneticdipole luminosity, so that in order to account for the shortest (τ ˜ 0.1 s) bursts, the pulsars must rotate very fast (with periodP ˜ 0.5 ms) and have magnetic fields of 1016 - 1017 G. Though the high pulsar frequency was anticipated (Qadir and Rafique, 1986) and has been shown to be plausible (Abramowicz, 1990), the extremely high magnetic fields seem anomalous as observed neutron stars have fields below ˜ 1013 G. The problem with Usov's proposal is reduced by incorporating the relativistic corrections for fast rotating magnetic dipoles (Belinskyet al., 1994) or magnetic stars (De Paolis and Qadir, 1994). These corrections substantially enhance the radiation efficiency due to the existence of a magnetic synchrotron effect so that the magnetic field required for the explanation of the shortest gamma-ray bursts is strongly reduced. As such the model becomes much more plausible.

  5. Heat pipes - Thermal diodes

    NASA Astrophysics Data System (ADS)

    Aptekar, B. F.; Baum, J. M.; Ivanovskii, M. N.; Kolgotin, F. F.; Serbin, V. I.

    The performance concept and peculiarities of the new type of thermal diode with the trap and with the wick breakage are dealt with in the report. The experimental data were obtained and analysed for the working fluid mass and the volume of the liquid in the wick on the forward-mode limiting heat transfer. The flow rate pulsation of the working fluid in the wick was observed visually on the setup with the transparent wall. The quantitative difference on the data on the investigated thermal diode and on the identical heat pipes without the wick breakage is found experimentally concerning the forward-mode limiting heat transfer.

  6. Ceramic heat pipe wick

    NASA Technical Reports Server (NTRS)

    Seidenberg, Benjamin (Inventor); Swanson, Theodore (Inventor)

    1989-01-01

    A wick for use in a capillary loop pump heat pipe is disclosed. The wick material is an essentially uniformly porous, permeable, open-cell, silicon dioxide/aluminum oxide inorganic ceramic foam having a silica fiber ratio, by weight, of about 78 to 22, respectively, a density of 6 lbs/cu ft, and an average pore size of less than 5 microns. A representative material having these characteristics is Lockheed Missile and Space Company, Inc.'s HTP 6-22. This material is fully compatible with the freons and anhydrous ammonia and allows for the use of these very efficient working fluids, and others, in capillary loops.

  7. Polymeric heat pipe wick

    NASA Technical Reports Server (NTRS)

    Seidenberg, Benjamin

    1988-01-01

    A wick for use in a capillary loop pump heat pipe is described. The wick material is an essentially uniformly porous, permeable, open-cell, polyethylene thermoplastic foam having an ultrahigh average molecular weight of from approximately 1 to 5 million, and an average pore size of about 10 to 12 microns. A representative material having these characteristics is POREX UF, which has an average molecular weight of about 3 million. This material is fully compatible with the FREONs and anhydrous ammonia and allows for the use of these very efficient working fluids in capillary loops.

  8. Removal of Pipe Fouling Inside Pipes Using Ultrasonic Waves

    NASA Astrophysics Data System (ADS)

    Nakagawa, Noritoshi; Fujihara, Masaya; Wu, Chaoqun; Satonobu, Jun

    Since fouling generated inside pipes of chemistry plant equipment, shortens “its life”, periodical maintenance such as cleaning or replacement is needed. Therefore, the development of a safe and sanitary method of preventing a corrosion and blockage inside pipes is desired. In this study, a vibration system, composed of a bolt-clamped Langevin transducer and a pipe, was employed to experimentally study the possibility of fouling removal. In the experiment, a flexural vibration was excited in a pipe containing fouling using ultrasonic waves. When the pipe was made to vibrate, with calcium carbonate or starch used as the fouling, it was shown that the fouling was diffused into the air, and except at the node of the flexural vibration, the fouling was removed completely. Also, the result showed that a higher input voltage to the transducer was more effective in removing the fouling.

  9. The thermonuclear-flash model for X-ray burst sources - A new tool for observing neutron stars

    NASA Technical Reports Server (NTRS)

    Joss, P. C.

    1979-01-01

    The helium-flash model for X-ray burst sources, in which matter is presumed to accrete onto the surface of a neutron star, is discussed. Attention is given to the accretion process, nuclear burning, X-ray emission, and the energy released by convection as well as by radiative diffusion near the surface. The rise times of observed bursts, their spectral evolution, and the properties of the spectrally soft X-ray transients are considered. Problems in interpreting the continuum spectra are discussed, along with problems in the detection and measurement of line features in the spectra. Also considered are the ratio of time-averaged persistent luminosity to time-averaged burst luminosity, peak burst luminosities, and the possibility of detecting binary membership for burst sources.

  10. The LOFT burst alert system and its burst onboard trigger

    NASA Astrophysics Data System (ADS)

    Schanne, Stéphane; Götz, Diego; Le Provost, Hervé; Château, Frédéric; Bozzo, Enrico; Brandt, Søren

    2014-07-01

    The ESA M3 candidate mission LOFT (Large Observatory For x-ray Timing) has been designed to study strong gravitational fields by observing compact objects, such as black-hole binaries or neutron-star systems and supermassive black-holes, based on the temporal analysis of photons collected by the primary instrument LAD (Large Area Detector), sensitive to X-rays from 2 to 50 keV, offering a very large effective area (>10 m2), but a small field of view (ø<1°). Simultaneously the second instrument WFM (Wide Field Monitor), composed of 5 coded-mask camera pairs (2-50 keV), monitors a large part of the sky, in order to detect and localize eruptive sources, to be observed with the LAD after ground-commanded satellite repointing. With its large field of view (>π sr), the WFM actually detects all types of transient sources, including Gamma-Ray Bursts (GRBs), which are of primary interest for a world-wide observers community. However, observing the quickly decaying GRB afterglows with ground-based telescopes needs the rapid knowledge of their precise localization. The task of the Loft Burst Alert System (LBAS) is therefore to detect in near-real- time GRBs (about 120 detections expected per year) and other transient sources, and to deliver their localization in less than 30 seconds to the observers, via a VHF antenna network. Real-time full resolution data download to ground being impossible, the real-time data processing is performed onboard by the LBOT (LOFT Burst On-board Trigger system). In this article we present the LBAS and its components, the LBOT and the associated ground-segment.