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. Solving FRP piping and ducting problems

    SciTech Connect

    Britt, F.

    1997-12-01

    This paper presents an analytical approach to the design and installation of FRP piping and duct systems that can be used by piping designers and engineers to prevent failures. Design, installation, testing, and start up procedures will be presented that have proven to provide safe and long lasting service. Procedures offered will insure the most cost effective system based on operational requirements.

  3. OTEC Cold Water Pipe Design for Problems Caused by Vortex-Excited Oscillations.

    DTIC Science & Technology

    to structural damage and to destructive failures. The cold water pipe of an OTEC plant is nominally a bluff, flexible cylinder with a large aspect... OTEC cold water pipe. Practical design calculations are given as examples throughout the various sections of the report. This report is limited in...structural response parameters relevant to the OTEC cold water pipe. There are important problems associated with the shedding of vortices from cylinders in

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 46 CFR 193.15-15 - Piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... fittings shall have a bursting pressure of not less than 6,000 pounds per square inch. (b) All piping, in... by blowing out the piping with air at a pressure of at least 100 pounds per square inch....

  15. 46 CFR 193.15-15 - Piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... fittings shall have a bursting pressure of not less than 6,000 pounds per square inch. (b) All piping, in... by blowing out the piping with air at a pressure of at least 100 pounds per square inch....

  16. 46 CFR 193.15-15 - Piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... fittings shall have a bursting pressure of not less than 6,000 pounds per square inch. (b) All piping, in... by blowing out the piping with air at a pressure of at least 100 pounds per square inch....

  17. 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.

  18. The canonical problem of the fluid-conveying pipe and radiation of the knowledge gained to other dynamics problems across Applied Mechanics

    NASA Astrophysics Data System (ADS)

    Paı¨doussis, M. P.

    2008-02-01

    The basic dynamics of pipes conveying fluid is reviewed, establishing why this system has become a model dynamical problem. The paper then discusses the radiation of the experience gained in studying this problem into other areas of Applied Mechanics, particularly other problems in fluid-structure interactions involving slender structures and axial flows; specifically the dynamics of (i) quasi-cylindrical bodies in axial flow or towed in quiescent fluid; (ii) cylindrical shells containing or immersed in axial flow; and (iii) plates in axial flow. Applications, some of them wholly unexpected when the work was done, are noted throughout.

  19. 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.…

  20. Some major problems with existing models and terminology associated with kimberlite pipes from a volcanological perspective, and some suggestions

    NASA Astrophysics Data System (ADS)

    Cas, R. A. F.; Hayman, P.; Pittari, A.; Porritt, L.

    2008-06-01

    Five significant problems hinder advances in understanding of the volcanology of kimberlites: (1) kimberlite geology is very model driven; (2) a highly genetic terminology drives deposit or facies interpretation; (3) the effects of alteration on preserved depositional textures have been grossly underestimated; (4) the level of understanding of the physical process significance of preserved textures is limited; and, (5) some inferred processes and deposits are not based on actual, modern volcanological processes. These issues need to be addressed in order to advance understanding of kimberlite volcanological pipe forming processes and deposits. The traditional, steep-sided southern African pipe model (Class I) consists of a steep tapering pipe with a deep root zone, a middle diatreme zone and an upper crater zone (if preserved). Each zone is thought to be dominated by distinctive facies, respectively: hypabyssal kimberlite (HK, descriptively called here massive coherent porphyritic kimberlite), tuffisitic kimberlite breccia (TKB, descriptively here called massive, poorly sorted lapilli tuff) and crater zone facies, which include variably bedded pyroclastic kimberlite and resedimented and reworked volcaniclastic kimberlite (RVK). Porphyritic coherent kimberlite may, however, also be emplaced at different levels in the pipe, as later stage intrusions, as well as dykes in the surrounding country rock. The relationship between HK and TKB is not always clear. Sub-terranean fluidisation as an emplacement process is a largely unsubstantiated hypothesis; modern in-vent volcanological processes should initially be considered to explain observed deposits. Crater zone volcaniclastic deposits can occur within the diatreme zone of some pipes, indicating that the pipe was largely empty at the end of the eruption, and subsequently began to fill-in largely through resedimentation and sourcing of pyroclastic deposits from nearby vents. Classes II and III Canadian kimberlite models

  1. 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.

  2. 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.

  3. Inhomogeneous temperature problems inside a Li/SOCl2 cell - Homogenization by integrated heat pipes

    NASA Astrophysics Data System (ADS)

    Lefriec, C.; Suleiman, A.; Alexandre, A.

    1992-07-01

    The effect of the temperature gradient on the electrical capacity of the lithium/thionyl chloride (Li/SOCl2) cells and the dependence of internal heat generation on the temperature level were investigated by studying the thermal behavior of a cell constituted by a number of couples stacken in a stainless steel cylinder during a discharge profile. It is shown that the temperature gradient between couples affected the depth of discharge, indicating that this gradient must be limited to prevent discrepancy in couple's voltage and inversion phenomenon. It was found that a cooling concept based on integrated heat pipes is effective in reducing the temperature gradient and in yielding homogeneous cell behavior in overdischarge.

  4. 49 CFR 178.338-8 - Pressure relief devices, piping, valves, and fittings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) Piping, valves, and fittings. (1) The burst pressure of all piping, pipe fittings, hoses and other... pressure of the tank. Additionally, the burst pressure may not be less than 4 times any higher pressure to..., and fittings have been tested after installation with gas or air and proved leak tight at not...

  5. 49 CFR 178.338-8 - Pressure relief devices, piping, valves, and fittings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) Piping, valves, and fittings. (1) The burst pressure of all piping, pipe fittings, hoses and other... pressure of the tank. Additionally, the burst pressure may not be less than 4 times any higher pressure to..., and fittings have been tested after installation with gas or air and proved leak tight at not...

  6. 49 CFR 178.338-8 - Pressure relief devices, piping, valves, and fittings.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) Piping, valves, and fittings. (1) The burst pressure of all piping, pipe fittings, hoses and other... pressure of the tank. Additionally, the burst pressure may not be less than 4 times any higher pressure to..., and fittings have been tested after installation with gas or air and proved leak tight at not...

  7. 46 CFR 108.447 - Piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., and fitting in a CO2 system must have a bursting pressure of at least 420 kilograms per square centimeter (6,000 pounds per square inch). (b) All piping for a CO2 system of nominal size of 19.05... heavy). (c) Each pipe, valve, and fitting made of ferrous materials in a CO2 system must be...

  8. Heat Pipes

    ERIC Educational Resources Information Center

    Lewis, J.

    1975-01-01

    Describes the construction, function, and applications of heat pipes. Suggests using the heat pipe to teach principles related to heat transfer and gives sources for obtaining instructional kits for this purpose. (GS)

  9. 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)

  10. 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

  11. 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.

  12. Underground pipeline laying using the pipe-in-pipe system

    NASA Astrophysics Data System (ADS)

    Antropova, N.; Krets, V.; Pavlov, M.

    2016-09-01

    The problems of resource saving and environmental safety during the installation and operation of the underwater crossings are always relevant. The paper describes the existing methods of trenchless pipeline technology, the structure of multi-channel pipelines, the types of supporting and guiding systems. The rational design is suggested for the pipe-in-pipe system. The finite element model is presented for the most dangerous sections of the inner pipes, the optimum distance is detected between the roller supports.

  13. 49 CFR 178.337-9 - Pressure relief devices, piping, valves, hoses, and fittings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., valves, hose, and fittings. (1) The burst pressure of all piping, pipe fittings, hose and other pressure... of the cargo tank. Additionally, the burst pressure may not be less than 4 times any higher pressure... must be tested for leakage at not less than 225 psig using dry air or inert gas. (c) Marking inlets...

  14. 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.

  15. 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.

  16. 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

  17. 46 CFR 34.15-15 - Piping-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Systems, Details § 34.15-15 Piping—T/ALL. (a) The piping, valves, and fittings shall have a bursting... be tested by blowing out the piping with the air at a pressure of at least 100 pounds p.s.i....

  18. 46 CFR 34.15-15 - Piping-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Systems, Details § 34.15-15 Piping—T/ALL. (a) The piping, valves, and fittings shall have a bursting... be tested by blowing out the piping with the air at a pressure of at least 100 pounds p.s.i....

  19. 46 CFR 34.15-15 - Piping-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Systems, Details § 34.15-15 Piping—T/ALL. (a) The piping, valves, and fittings shall have a bursting... be tested by blowing out the piping with the air at a pressure of at least 100 pounds p.s.i....

  20. 46 CFR 34.15-15 - Piping-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Systems, Details § 34.15-15 Piping—T/ALL. (a) The piping, valves, and fittings shall have a bursting... be tested by blowing out the piping with the air at a pressure of at least 100 pounds p.s.i....

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 46 CFR 108.447 - Piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., and fitting in a CO2 system must have a bursting pressure of at least 420 kilograms per square centimeter (6,000 pounds per square inch). (b) All piping for a CO2 system of nominal size of 19.05 millimeters (3/4 inch) inside diameter or less must be at least Schedule 40 (standard weight) and all...

  6. High temperature loop heat pipes

    SciTech Connect

    Anderson, W.G.; Bland, J.J.; Fershtater, Y.; Goncharov, K.A.; Nikitkin, M.; Juhasz, A.

    1995-12-31

    Advantages of loop heat pipes over conventional heat pipes include self-priming during start-up, improved tolerance for noncondensible gas, and ability for ground testing in any orientation. The applications for high temperature, alkali-metal working fluid loop heat pipes include space radiators, and bimodal systems. A high temperature loop heat pipe was fabricated and tested at 850 K, using cesium as the working fluid. Previous loop heat pipes were tested with ambient temperature working fluids at temperatures below about 450 K. The loop heat pipe had a titanium envelope, and a titanium aluminide wick. The maximum cesium loop heat pipe power was only about 600 watts, which was lower the predicted 1,000 W power. The power limitation may be due to a wettability problem with the cesium not completely wetting the titanium aluminide wick. This would reduce the pumping capability of the wick, and the maximum power that the heat pipe could carry. This problem could be solved by using a refractory metal powder wick, since the alkali metals are known to wet refractory metal wicks.

  7. Silicate globules in kyanite from grospydites of the Zagadochnaya kimberlite pipe, Yakutia: The problem of the origin

    NASA Astrophysics Data System (ADS)

    Tomilenko, A. A.; Kovyazin, S. V.; Pokhilenko, L. N.; Sobolev, N. V.

    2011-01-01

    The results of complex study of silicate globules and α-quartz paramorphs after coesite in kyanite from grospydites from the Zagadochnaya kimberlite pipe, Yakutia, using optical and scanning electron spectroscopy, electron and ion microprobes, LA ICP MS and Raman spectroscopy, are presented. The existence of radial fractures diverging from silicate globules into the matrix (kyanite) attests to the fact that the content of the globules is extremely condensed. A zonal structure is usually typical for globules: a coat and a core, which can be explicitly distinguished under the electron microscope, can be differentiated in them. Compositionally, the coat of the globule corresponds to potassium feldspar (wt %: 66.4 SiO2; 16.9 Al2O3; 0.4 FeO; 0.1 CaO; 0.2 Na2O; 14.7 K2O). The globules were also detected in which along with K, a high content of Na and Ca was also ascertained in the silicate coat. The globule coat is considerably enriched with Ba, La, Ce, Nb, and a number of other noncompatible elements as compared with xenolith minerals. The water content in globules is ˜0.6 wt %. As compared with the host mineral (kyanite), the core part of the globules is also enriched with Co, Ni, Zn, and Cu; their content in kyanite is negligibly low. The entire data collection attests to the fact that the formation of silicate globules could have been caused by interaction of the conservated fluid and/or water-silicate melt with the host mineral and crystalline inclusions of clinopyroxene and garnet with decreasing pressure during the transportation of grospydite xenoliths by the kimberlite melt to the Earth's surface.

  8. 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.

  9. Heat Pipes

    NASA Astrophysics Data System (ADS)

    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. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Monitoring pipes for residual alpha contamination

    SciTech Connect

    MacArthur, D.; Rawool-Sullivan, M.; Dockray, T.

    1996-09-01

    The sensitivity and application of traditional alpha monitors is limited by the short range of alpha particles in air and in solid materials. Detecting small amounts of alpha-emitting contamination inside pipes presents particular problems. The alpha particle cannot penetrate the walls of the pipe. Associated gamma-ray detection and active neutron interrogation is often used to detect large amounts of radioactive material in pipes, but these methods are of limited use for detecting small amounts of contamination. Insertion of a traditional alpha probes works well in large diameter straight pipes, but is increasingly difficult as the pipe network becomes smaller in diameter and more complex. Monitors based on long-range alpha detection (LRAD) detect ionization of the ambient air rather than the alpha particles themselves. A small fan draws the ions into an externally mounted ion detector. Thus, the air in the pipe serves as both the detector gas and the mechanism for transporting the alpha-induced ions to a detection grid outside the pipe. All of the ions created by all of the contamination in the pipe can be measured in a single detector. Since ambient air serves as the probe, crushed or twisted sections of pipe can be monitored almost as effectively as straight sections. The pipe monitoring system described in the paper was tested both at LANL and BNFL`s Sellafield reprocessing facility in the UK. In this paper, we report on the first field tests of the pipe monitoring system.

  15. 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.

  16. PBF (PER620) interior, basement level. Detail of coolant piping. Date: ...

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

    PBF (PER-620) interior, basement level. Detail of coolant piping. Date: May 2004. INEEL negative no. HD-41-5-2 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

  17. Isentropic fluid dynamics in a curved pipe

    NASA Astrophysics Data System (ADS)

    Colombo, Rinaldo M.; Holden, Helge

    2016-10-01

    In this paper we study isentropic flow in a curved pipe. We focus on the consequences of the geometry of the pipe on the dynamics of the flow. More precisely, we present the solution of the general Cauchy problem for isentropic fluid flow in an arbitrarily curved, piecewise smooth pipe. We consider initial data in the subsonic regime, with small total variation about a stationary solution. The proof relies on the front-tracking method and is based on [1].

  18. How Long does a Burst Burst?

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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 burst based on both γ-ray and X-ray light curves rather than using γ-ray observations alone. We find that t burst can be reliably measured in 343 GRBs. Within this "good" sample, 21.9% GRBs have t burst >~ 103 s and 11.5% GRBs have t burst >~ 104 s. There is an apparent bimodal distribution of t burst in this sample. However, when we consider an "undetermined" sample (304 GRBs) with t burst possibly falling in the gap between GRB duration T 90 and the first X-ray observational time, as well as a selection effect against t burst falling into the first Swift orbital "dead zone" due to observation constraints, the intrinsic underlying t 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 90 duration and it does not even correlate with T 90. It would be premature to make a direct connection between T 90 and the size of the progenitor star.

  19. Sink or swim pipe

    SciTech Connect

    Dubois, B.C.; Rhines, J.A.

    1985-07-01

    The development of a six-inch ID flexible pipe system for use as a rapidly deployable offshore fuel delivery system is described. Pipe design data, pipe construction, and advantages of the offshore petroleum delivery system are discussed.

  20. Hydrological connectivity of soil pipes

    NASA Astrophysics Data System (ADS)

    Holden, J.

    2003-04-01

    Natural soil pipes are common in many parts of the world and particularly in blanket peat uplands yet there are problems in finding and defining soil pipe networks which are often located deep within the peat. Pipeflow can contribute a large proportion of runoff to the river systems in these upland environments and may significantly influence catchment sediment and solute yield. Ground penetrating radar (GPR) technology has recently been developed for non-destructive identification and mapping of soil pipes in peat catchments. While GPR can identify subsurface cavities, it cannot alone determine hydrological connectivity between one cavity and another. This poster presents results from an experiment to test the ability of GPR to establish hydrological connectivity between pipes through use of a tracer solution. Tracers such as sodium chloride were injected at a constant rate into an open pipe cavity. The GPR was moved across the test area downslope. The resultant radargrams were analysed and significantly increased reflectance was observed from a selection of cavities downslope. It was thus possible to determine hydrological connectivity of soil pipes within a dense pipe network across a hillslope without ground disturbance. In addition, tracers were added to the peat surface upslope of known pipe networks. It was possible to then trace the movement of water across and through the hillslope by using GPR to establish the connectivity of a range of flowpaths. Often pipe networks were supplied with water from overland flow entering through cracks and openings where the soil pipe was near the peat surface. Downslope, pipeflow contributed not only directly to streamflow but also to overland flow and near-surface throughflow on the hillslope. The same water that was within a pipe network at four metres depth could become near-surface throughflow outside of the pipe network a few metres down slope. These data allow the first three-dimensional picture of subsurface

  1. 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.

  2. 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.

  3. 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.

  4. PBF (PER620) interior, second basement level. Coolant and tank piping. ...

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

    PBF (PER-620) interior, second basement level. Coolant and tank piping. Mark on vertical pipe says, "H.P. Demin. Water." (High pressure demineralized water.) Date: March 2004. INEEL negative no. HD-41-4-3 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

  5. 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

  6. 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.

  7. Ultrasonic pipe assessment

    DOEpatents

    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.

  8. The effect of white or grey PVC pipe and its joint solvents (primer and cement) on odour problems in drinking water distribution systems.

    PubMed

    Wiesenthal, K E; Suffet, I H

    2007-01-01

    A study of the production of odour-causing compounds was conducted from the leaching of polyvinylchloride (PVC) pipe and its joints, primer and cement, into drinking water distribution systems. Flavour Profile Analysis (FPA), closed-loop stripping analysis--gas chromatography/mass spectrometry (CLSA-GC/MS) and sensory-GC analysis of white or grey PVC alone found no odour-causing compounds produced during the leaching experiments. FPA analysis of the PVC's primer and cement leached alone and/or when applied to grey or white PVC pipes produced a glue/varnish odour. A sweet/phenolic odour replaced the glue/varnish odour after the leached media were diluted with Milli-Q water to threshold odour intensity. Three compounds were responsible for the sweet/phenolic odour and were observed by sensoryGC analysis. The leaching study of the PVC pipe with its joint solvents (primer and cement) concluded that the original solvent compounds, and their reaction products that formed during the bonding process on the PVC pipe, were a primary source of the glue/varnish odour. The original compounds of the PVC primer and cement were not detected by CLSA-GC/MS, due to their high volatility during the CLSA extraction method and/or these compounds appeared in a solvent peak of the GC/MS analysis. However, the original primer and cement chemicals (acetone, tetrahydrofuran, methyl ethyl ketone, and cyclohexanone) had a glue/varnish odour. A total of nine odorous GC peaks were produced as reaction products from leaching of primer in water and white or grey PVC pipe with primer and cement, and white or grey PVC with primer only. None of these compounds were among the chemical ingredients in the original primer or cement. Four GC peaks with a sweet/phenolic odour were present due to the reaction products of the cement leached with white or grey PVC. None of these compounds were positively identified.

  9. A burst segmentation-deflection routing contention resolution mechanism in OBS networks

    NASA Astrophysics Data System (ADS)

    Guan, Ai-hong; Wang, Bo-yun

    2012-01-01

    One of the key problems to hinder the realization of optical burst switching (OBS) technology in the core networks is the losses due to the contention among the bursts at the core nodes. Burst segmentation is an effective contention resolution technique used to reduce the number of packets lost due to the burst losses. In our work, a burst segmentation-deflection routing contention resolution mechanism in OBS networks is proposed. When the contention occurs, the bursts are segmented according to the lowest packet loss probability of networks firstly, and then the segmented burst is deflected on the optimum routing. An analytical model is proposed to evaluate the contention resolution mechanism. Simulation results show that high-priority bursts have significantly lower packet loss probability and transmission delay than the low-priority. And the performance of the burst lengths, in which the number of segments per burst distributes geometrically, is more effective than that of the deterministically distributed burst lengths.

  10. 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.

  11. Propeller tone bursts

    NASA Technical Reports Server (NTRS)

    Succi, G. P.; Munro, D. H.; Ingard, K. U.

    1983-01-01

    Intense high frequency (25-38 kHz) tone bursts have been observed in acoustic tests of a scale model of a general aviation propeller. The amplitude of the tone burst is approximately equal to the amplitude of the propeller noise signature. The conditions necessary for the production of these tone bursts are described. The experiments indicate that the origin of these bursts is a periodic flow oscillation on the suction surface of the propeller blade tips which may be due to the interaction between an oscillating shock wave and a laminar boundary layer.

  12. Neutrino bursts from gamma-ray bursts

    NASA Technical Reports Server (NTRS)

    Paczynski, Bohdan; Xu, Guohong

    1994-01-01

    If gamma-ray bursts originate at cosmological distances, as strongly indicated by the results from Burst and Transient Source Experiment (BATSE) on the Compton Gamma-Ray Observatory (CGRO), then ultrarelativistic ejecta are the likely consequence of the highly super-Eddington luminosity of the sources. If the energy injection rate varies with time, then the Lorentz factor of the wind also varies, and the shells of ejected matter collide with each other. The collisions between baryons produce pions which decay into high-energy photons, electrons, electron positron pairs, and neutrino pairs. The bulk Lorentz factor of approximately 300 is required if our model is to be compatible with the observed millisecond variability. The strongest gamma-ray bursts are observed to deliver approximately 10(exp -4) ergs/sq cm in 100-200 keV photons. In our scenario more energy may be delivered in a neutrino burst. Typical neutrinos may be approximately 30 GeV if the protons have a Maxwellian energy distribution, and up to approximately TeV if the protons have a power-law distribution. Such neutrino bursts are close to the detection limit of the DUMAND II experiment.

  13. 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.

  14. 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.

  15. 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.

  16. SHEBA prompt burst dynamics

    SciTech Connect

    Kimpland, R.

    1997-12-31

    The Solution High-Energy Burst Assembly (SHEBA), located at the Los Alamos Critical Experiments Facility, is a homogeneous liquid-fueled reactor that is being prepared for prompt burst operation. As part of the preparations, a reactor safety study was performed in support of the new SHEBA experiment plan. This study looked at the maximum power, total energy yield, and maximum transient pressures that may occur in the reactor during prompt burst operation. The goal of this study is to analyze the neutronic and hydrodynamic behavior of the reactor during burst operation, and to ensure that prompt burst operation does not damage the reactor or exceed the safety envelope of the facility`s Safety Analysis Report (SAR).

  17. 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.

  18. Mixing in Helical Pipes

    NASA Astrophysics Data System (ADS)

    Gratton, Michael B.; Bernoff, Andrew J.

    2001-11-01

    We consider advection and diffusion of a passive scalar in a helical pipe. By assuming that the curvature and torsion are small (equivalent to small Dean number) and the Reynolds number is moderate, we can use a closed form approximation, due to Dean (1927) and Germano (1982), for the induced recirculation. We investigate the problem numerically using a split-step particle method for a variety of localized initial conditions. The problem is governed by two parameters: a nondimensional diffusion constant D (typically small), and the scaled ratio of torsion to curvature λ. At small times, the longitudinal width of the particle distribution, σ, is governed by diffusive effects (σ ∝ √Dt). At large times, Taylor diffusion dominates (σ ∝ √t/D). However, at intermediate times, a ballistic region exists where the width spreads linearly, as postulated by Mezic & Wiggins (1994). We also discuss how these various behaviors scale with the parameters D and λ.

  19. 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.

  20. Type III burst pair

    NASA Astrophysics Data System (ADS)

    Ning, Zongjun; Fu, Qijun; Lu, Quankang

    2000-05-01

    We present a special solar radio burst detected on 5 January 1994 using the multi-channel (50) spectrometer (1.0-2.0 GHz) of the Beijing Astronomical Observatory (BAO). Sadly, the whole event could not be recorded since it had a broader bandwidth than the limit range of the instrument. The important part was obtained, however. The event is composed of a normal drift type III burst on the lower frequency side and a reverse drift type III burst appearing almost simultaneously on the high side. We call the burst type III a burst pair. It is a typical characteristic of two type III bursts that they are morphologically symmetric about some frequency from 1.64 GHz to 1.78 GHz on the dynamic spectra records, which indicates that there are two different electron beams from the same acceleration region travelling simultaneously in opposite directions (upward and downward). A magnetic reconnection mode is a nice interpretation of type III burst pair since the plasma beta β~=0.01 is much less than 1 and the beams have velocity of about 1.07×10^8 cm s^-1 after leaving the reconnection region if we assume that the ambient magnetic field strength is about 100 G.

  1. Type III burst pair.

    NASA Astrophysics Data System (ADS)

    Zongjun, Ning; Fu, Qijun; Quankang, Lu

    2000-05-01

    Presents a special solar radio burst detected on 5 January 1994 using the multi-channel (50) spectrometer (1.0 - 2.0 GHz) of the Beijing Astronomical Observatory. Sadly, the whole event could not be recorded since it had a broader bandwidth than the limit range of the instrument. The important part was obtained, however. The event is composed of a normal drift type III burst on the lower frequency side and a reverse drift type III burst appearing almost simultaneously on the high side. The authors call the burst type III a burst pair. It is a typical characteristic of two type III bursts that they are morphologically symmetric about some frequency from 1.64 GHz to 1.78 GHz on the dynamic spectra records, which indicates that there are two different electron beams from the same acceleration region travelling simultaneously in opposite directions (upward and downward). A magnetic reconnection mode is an interpretation of type III burst pair.

  2. Speech Problems

    MedlinePlus

    ... thinking, but it becomes disorganized as they're speaking. So, someone who clutters may speak in bursts ... refuse to wait patiently for them to finish speaking. If you have a speech problem, it's fine ...

  3. Theta-Burst LTP

    PubMed Central

    Larson, John; Munkácsy, Erin

    2014-01-01

    This review covers the spatial and temporal rules governing induction of hippocampal long-term potentiation (LTP) by theta-burst stimulation. Induction of LTP in field CA1 by high frequency stimulation bursts that resemble the burst discharges (complex-spikes) of hippocampal pyramidal neurons involves a multiple-step mechanism. A single burst is insufficient for LTP induction because it evokes both excitatory and inhibitory currents that partially cancel and limit postsynaptic depolarization. Bursts repeated at the frequency (~5 Hz) of the endogenous theta rhythm induce maximal LTP, primarily because this frequency disables feed-forward inhibition and allows sufficient postsynaptic depolarization to activate voltage-sensitive NMDA receptors. The disinhibitory process, referred to as “priming”, involves presynaptic GABA autoreceptors that inhibit GABA release. Activation of NMDA receptors allows a calcium flux into dendritic spines that serves as the proximal trigger for LTP. We include new data showing that theta-burst stimulation is more efficient than other forms of stimulation for LTP induction. In addityion, we demonstrate that associative interactions between synapses activated during theta-bursts are limited to major dendritic domains since such interactions occur within apical or basal dendritic trees but not between them. We review evidence that recordings of electrophysiological responses during theta burst stimulation can help to determine if experimental manipulations that affect LTP do so by affecting events antecedent to the induction process, such as NMDA receptor activation, or downstream signaling cascades that result from postsynaptic calcium fluxes. Finally, we argue that theta-burst LTP represents a minimal model for stable, non-decremental LTP that is more sensitive to a variety of experimental manipulations than is LTP induced by other stimulation paradigms. PMID:25452022

  4. 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.

  5. Pipe-to-pipe impact program

    SciTech Connect

    Alzheimer, J.M.; Bampton, M.C.C.; Friley, J.R.; Simonen, F.A.

    1984-06-01

    This report documents the tests and analyses performed as part of the Pipe-to-Pipe Impact (PTPI) Program at the Pacific Northwest Laboratory. This work was performed to assist the NRC in making licensing decisions regarding pipe-to-pipe impact events following postulated breaks in high energy fluid system piping. The report scope encompasses work conducted from the program's start through the completion of the initial hot oil tests. The test equipment, procedures, and results are described, as are analytic studies of failure potential and data correlation. Because the PTPI Program is only partially completed, the total significance of the current test results cannot yet be accurately assessed. Therefore, although trends in the data are discussed, final conclusions and recommendations will be possible only after the completion of the program, which is scheduled to end in FY 1984.

  6. 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)

  7. 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.

  8. Pipe protection bibliography

    SciTech Connect

    Guy, N.G.

    1987-01-01

    Pipes and pipelines are being used for an ever widening range of materials, for increasing flows and in harsher applications. There is also more legal and social pressure to reduce the hazards associated with handling materials in pipes. All of this increases the demand for improved pipe reliability. Two of the major preventable causes of pipe failure are corrosion and wear. These may result from the pipe surroundings, or from the material which is carried and it is often impossible to prevent failure by the choice of pipe materials and design. However, additional pipe protection measures are available and it is these measures which are considered in this bibliography. The most common pipe protection methods are the application of coatings and the use of cathodic protection. Accordingly, much of this bibliography is devoted to these techniques. Articles dealing with other means of protecting pipes have also been included. The bibliography covers the protection of oil pipes, (both offshore and on land); water supply systems; gas distribution systems; sewer pipes; pipes for hydraulic and pneumatic transport of solids; power plant pipework; process plant pipework.

  9. Phase analysis method for burst onset prediction

    NASA Astrophysics Data System (ADS)

    Stellino, Flavio; Mazzoni, Alberto; Storace, Marco

    2017-02-01

    The response of bursting neurons to fluctuating inputs is usually hard to predict, due to their strong nonlinearity. For the same reason, decoding the injected stimulus from the activity of a bursting neuron is generally difficult. In this paper we propose a method describing (for neuron models) a mechanism of phase coding relating the burst onsets with the phase profile of the input current. This relation suggests that burst onset may provide a way for postsynaptic neurons to track the input phase. Moreover, we define a method of phase decoding to solve the inverse problem and estimate the likelihood of burst onset given the input state. Both methods are presented here in a unified framework, describing a complete coding-decoding procedure. This procedure is tested by using different neuron models, stimulated with different inputs (stochastic, sinusoidal, up, and down states). The results obtained show the efficacy and broad range of application of the proposed methods. Possible applications range from the study of sensory information processing, in which phase-of-firing codes are known to play a crucial role, to clinical applications such as deep brain stimulation, helping to design stimuli in order to trigger or prevent neural bursting.

  10. 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.

  11. 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.

  12. Pipe Line Control

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The array of tanks, pipes and valves in the photo below is a petroleum tank farm in Georgia, part of a petrochemical pipe line system that moves refined petroleum products from Texas and Louisiana to the mid-Eastern seaboard. The same pipes handle a number of different products, such as gasoline, kerosene, jet fuel or fuel oil. The fluids are temporarily stored in tanks, pumped into the pipes in turn and routed to other way stations along the pipe line. The complex job of controlling, measuring and monitoring fuel flow is accomplished automatically by a computerized control and communications system which incorporates multiple space technologies.

  13. 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

  14. 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.

  15. 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

  16. A Burst to See

    NASA Astrophysics Data System (ADS)

    2008-04-01

    On 19 March, Nature was particularly generous and provided astronomers with the wealth of four gamma-ray bursts on the same day. But that was not all: one of them is the most luminous object ever observed in the Universe. Despite being located in a distant galaxy, billions of light years away, it was so bright that it could have been seen, for a brief while, with the unaided eye. ESO PR Photo 08a/08 ESO PR Photo 08a/08 The REM Telescope and TORTORA Camera Gamma-ray bursts (GRBs) are short flashes of energetic gamma-rays lasting from less than a second to several minutes. They release a tremendous quantity of energy in this short time making them the most powerful events since the Big Bang. It is now widely accepted that the majority of the gamma-ray bursts signal the explosion of very massive, highly evolved stars that collapse into black holes. Gamma-ray bursts, which are invisible to our eyes, are discovered by telescopes in space. After releasing their intense burst of high-energy radiation, they become detectable for a short while in the optical and in the near-infrared. This 'afterglow' fades very rapidly, making detailed analysis possible for only a few hours after the gamma-ray detection. This analysis is important in particular in order to determine the GRB's distance and, hence, intrinsic brightness. The gamma-ray burst GRB 080319B was detected by the NASA/STFC/ASI Swift satellite. "It was so bright that it almost blinded the Swift instruments for a while," says Guido Chincarini, Italian principal investigator of the mission. A bright optical counterpart was soon identified in the Boötes Constellation (the "Bear Driver" or "Herdsman"). A host of ground-based telescopes reacted promptly to study this new object in the sky. In particular, the optical emission was detected by a few wide-field cameras on telescopes that constantly monitor a large fraction of the sky, including the TORTORA camera in symbiosis with the 0.6-m REM telescope located at La Silla

  17. Fast Radio Bursts

    NASA Astrophysics Data System (ADS)

    Kaspi, Victoria M.

    2017-01-01

    Fast Radio Bursts (FRBs) are a recently discovered phenomenon consisting of short (few ms) bursts of radio waves that have dispersion measures that strongly suggest an extragalactic and possibly cosmological origin. Current best estimates for the rate of FRBs is several thousand per sky per day at radio frequencies near 1.4 GHz. Even with so high a rate, to date, fewer than 20 FRBs have been reported, with one source showing repeated bursts. In this talk I will describe known FRB properties including what is known about the lone repeating source, as well as models for the origin of these mysterious events. I will also describe the CHIME radio telescope, currently under construction in Canada. Thanks to its great sensitivity and unprecedented field-of-view, CHIME promises major progress on FRBs.

  18. 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.

  19. 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.

  20. The Glast Burst Monitor

    NASA Technical Reports Server (NTRS)

    Meegan, Charles

    2000-01-01

    The Gamma-Ray Large Area Space Telescope (GLAST) will include a secondary instrument to augment the observatory's capabilities for GRB studies. The GLAST Burst Monitor (GBK is a collaboration between Marshall Space Flight Center, the University of Huntsville, Alabama, and the Max Plank Institute for Extraterrestrial Physics. The purpose of the GBM is to extend energy coverage below the main instrument's lower limit of about 20 MeV, and to provide an on-board burst trigger and approximate location. The instrument consists of twelve NaI detectors and two BGO detectors. This combination provides energy coverage from a few keV up to about 30 MeV.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. A Signal Processing Approach with a Smooth Empirical Mode Decomposition to Reveal Hidden Trace of Corrosion in Highly Contaminated Guided Wave Signals for Concrete-Covered Pipes

    PubMed Central

    Rostami, Javad; Chen, Jingming; Tse, Peter W.

    2017-01-01

    Ultrasonic guided waves have been extensively applied for non-destructive testing of plate-like structures particularly pipes in past two decades. In this regard, if a structure has a simple geometry, obtained guided waves’ signals are easy to explain. However, any small degree of complexity in the geometry such as contacting with other materials may cause an extra amount of complication in the interpretation of guided wave signals. The problem deepens if defects have irregular shapes such as natural corrosion. Signal processing techniques that have been proposed for guided wave signals’ analysis are generally good for simple signals obtained in a highly controlled experimental environment. In fact, guided wave signals in a real situation such as the existence of natural corrosion in wall-covered pipes are much more complicated. Considering pipes in residential buildings that pass through concrete walls, in this paper we introduced Smooth Empirical Mode Decomposition (SEMD) to efficiently separate overlapped guided waves. As empirical mode decomposition (EMD) which is a good candidate for analyzing non-stationary signals, suffers from some shortcomings, wavelet transform was adopted in the sifting stage of EMD to improve its outcome in SEMD. However, selection of mother wavelet that suits best for our purpose plays an important role. Since in guided wave inspection, the incident waves are well known and are usually tone-burst signals, we tailored a complex tone-burst signal to be used as our mother wavelet. In the sifting stage of EMD, wavelet de-noising was applied to eliminate unwanted frequency components from each IMF. SEMD greatly enhances the performance of EMD in guided wave analysis for highly contaminated signals. In our experiment on concrete covered pipes with natural corrosion, this method not only separates the concrete wall indication clearly in time domain signal, a natural corrosion with complex geometry that was hidden and located inside the

  11. A Signal Processing Approach with a Smooth Empirical Mode Decomposition to Reveal Hidden Trace of Corrosion in Highly Contaminated Guided Wave Signals for Concrete-Covered Pipes.

    PubMed

    Rostami, Javad; Chen, Jingming; Tse, Peter W

    2017-02-07

    Ultrasonic guided waves have been extensively applied for non-destructive testing of plate-like structures particularly pipes in past two decades. In this regard, if a structure has a simple geometry, obtained guided waves' signals are easy to explain. However, any small degree of complexity in the geometry such as contacting with other materials may cause an extra amount of complication in the interpretation of guided wave signals. The problem deepens if defects have irregular shapes such as natural corrosion. Signal processing techniques that have been proposed for guided wave signals' analysis are generally good for simple signals obtained in a highly controlled experimental environment. In fact, guided wave signals in a real situation such as the existence of natural corrosion in wall-covered pipes are much more complicated. Considering pipes in residential buildings that pass through concrete walls, in this paper we introduced Smooth Empirical Mode Decomposition (SEMD) to efficiently separate overlapped guided waves. As empirical mode decomposition (EMD) which is a good candidate for analyzing non-stationary signals, suffers from some shortcomings, wavelet transform was adopted in the sifting stage of EMD to improve its outcome in SEMD. However, selection of mother wavelet that suits best for our purpose plays an important role. Since in guided wave inspection, the incident waves are well known and are usually tone-burst signals, we tailored a complex tone-burst signal to be used as our mother wavelet. In the sifting stage of EMD, wavelet de-noising was applied to eliminate unwanted frequency components from each IMF. SEMD greatly enhances the performance of EMD in guided wave analysis for highly contaminated signals. In our experiment on concrete covered pipes with natural corrosion, this method not only separates the concrete wall indication clearly in time domain signal, a natural corrosion with complex geometry that was hidden and located inside the

  12. 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.

  13. Splayed mirror light pipes

    SciTech Connect

    Swift, P.D.

    2010-02-15

    An expression is given for the transmission of the rectangular-section mirror light pipe. The expression is used to model throughputs for simulated solar conditions over a calender year. It is found that the splaying of a mirror light pipe results in a significant increase in throughputs particularly in winter months. (author)

  14. 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…

  15. Hardfacing takes the inside track in coating small diameter pipe

    SciTech Connect

    Not Available

    1985-03-01

    A Canadian company has adapted a standard hardfacing method to solve the problem of coating smaller pipe sizes. Small diameter piping and valves are hardfaced using a custom-designed plasma transferred arc (PTA) system. With an arrangement of automatically controlled mechanical arms, the firm is able to operate a PTA torch inside piping 6 to 12 inches in diameter and as long as 13 feet. Recently, the company improved the system so it can automatically hardface elbows up to 24 in. as well as straight runs of pipe.

  16. 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.

  17. The monster sound pipe

    NASA Astrophysics Data System (ADS)

    Ruiz, Michael J.; Perkins, James

    2017-03-01

    Producing a deep bass tone by striking a large 3 m (10 ft) flexible corrugated drainage pipe immediately grabs student attention. The fundamental pitch of the corrugated tube is found to be a semitone lower than a non-corrugated smooth pipe of the same length. A video (https://youtu.be/FU7a9d7N60Y) of the demonstration is included, which illustrates how an Internet keyboard can be used to estimate the fundamental pitches of each pipe. Since both pipes have similar end corrections, the pitch discrepancy between the smooth pipe and drainage tube is due to the corrugations, which lower the speed of sound inside the flexible tube, dropping its pitch a semitone.

  18. 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.

  19. The Double Firing Burst

    NASA Astrophysics Data System (ADS)

    2008-09-01

    Astronomers from around the world combined data from ground- and space-based telescopes to paint a detailed portrait of the brightest explosion ever seen. The observations reveal that the jets of the gamma-ray burst called GRB 080319B were aimed almost directly at the Earth. Uncovering the disc ESO PR Photo 28/08 A Gamma-Ray Burst with Two Jets Read more on this illuminating blast in the additional story. GRB 080319B was so intense that, despite happening halfway across the Universe, it could have been seen briefly with the unaided eye (ESO 08/08). In a paper to appear in the 11 September issue of Nature, Judith Racusin of Penn State University, Pennsylvania (USA), and a team of 92 co-authors report observations across the electromagnetic spectrum that began 30 minutes before the explosion and followed it for months afterwards. "We conclude that the burst's extraordinary brightness arose from a jet that shot material almost directly towards Earth at almost the speed of light - the difference is only 1 part in 20 000," says Guido Chincarini, a member of the team. Gamma-ray bursts are the Universe's most luminous explosions. Most occur when massive stars run out of fuel. As a star collapses, it creates a black hole or neutron star that, through processes not fully understood, drives powerful gas jets outward. As the jets shoot into space, they strike gas previously shed by the star and heat it, thereby generating bright afterglows. The team believes the jet directed toward Earth contained an ultra-fast component just 0.4 degrees across (this is slightly smaller than the apparent size of the Full Moon). This jet is contained within another slightly less energetic jet about 20 times wider. The broad component is more typical of other bursts. "Perhaps every gamma-ray burst has a narrow jet, but astronomers miss it most of the time," says team member Stefano Covino. "We happened to view this monster down the barrel of the very narrow and energetic jet, and the chance for

  20. Burst Populations and Detector Sensitivity

    NASA Technical Reports Server (NTRS)

    Band, David L.

    2003-01-01

    The F(sub T) (peak bolometric photon flux) vs. E(sub p) (peak energy) plane is a powerful tool to compare the burst populations detected by different detectors. Detector sensitivity curves in this plane demonstrate which burst populations the detectors will detect. For example, future CZT-based detectors will show the largest increase in sensitivity for soft bursts, and will be particularly well- suited to study X-ray rich bursts and X-ray Flashes. Identical bursts at different redshifts describe a track in the F(sub T)-E(sub p) plane.

  1. 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.

  2. 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.

  3. Jovian type III radio bursts

    NASA Technical Reports Server (NTRS)

    Kurth, W. S.; Gurnett, D. A.; Scarf, F. L.

    1989-01-01

    Radio bursts have been observed in the Voyager plasma wave data from Jupiter that bear a striking resemblance to solar type III radio bursts. The emissions lie in the frequency range near 10 kHz, have durations of a minute or so, and occur in a set of periodically spaced bursts. The spacing between primary bursts is typically 15 min, but the bursts may have additional components which recur on time scales of about 3 min. The similarity with solar type III radio bursts suggests a source mechanism involving the movement of energetic electrons through a density gradient in the plasma surrounding Jupiter. The periodicity of bursts suggests Io may be involved in the generation of waves, since the timing is similar to the Alfven wave travel time from one hemisphere to the other through the Io torus.

  4. 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.

  5. 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…

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. The pipes of pan.

    PubMed

    Chalif, David J

    2004-12-01

    The pipes of pan is the crowning achievement of Pablo Picasso's neoclassical period of the 1920s. This monumental canvas depicts a mythological Mediterranean scene in which two sculpted classical giants stare out, seemingly across the centuries, toward a distant and lost Arcadia. Picasso was influenced by Greco-Roman art during his travels in Italy, and his neoclassical works typically portray massive, immobile, and pensive figures. Pan and his pipes are taken directly from Greek mythological lore by Picasso and placed directly into 20th century art. He frequently turned to various mythological figures throughout his metamorphosing periods. The Pipes of Pan was also influenced by the painter's infatuation with the beautiful American expatriate Sara Murphy, and the finished masterpiece represents a revision of a previously conceived neoclassical work. The Pipes of Pan now hangs in the Musee Picasso in Paris.

  14. 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.

  15. 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.

  16. 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.

  17. Liquid Explosive in Pipes

    DTIC Science & Technology

    1994-01-01

    ETH - ethanolamine, ED - ethylenediamine, HMT - hexamethylenetetramine , MOR - morpholine. NM - nitromethane, PYR - pyridine, TETA...ror a detonable mixture in 16-mm ID pipe: diethylamine, diethylenetetramine, ethanolamine, ethylenediamine, hexamethylenetetramine , morpholine

  18. 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.

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

    NASA Astrophysics Data System (ADS)

    Sui, Haiteng; Niu, Wentie

    2016-09-01

    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.

  20. 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.

  1. 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.

  2. Alpha characterization inside pipes using ion-transport technology

    NASA Astrophysics Data System (ADS)

    Rojas, S. P.; Rawool-Sullivan, M. W.; Williams, K. G.; Vaccarella, J. A.

    Many DOE facilities have several miles of waste pipe systems that are internally contaminated with various and often undetermined radio nuclides. Unfortunately, currently acceptable alpha detection technologies are inefficient, time consuming, and do not address the problems presented by small diameter or curved pipes. In general, the problem of detecting alpha contamination on the inside surface of pipes is complicated by the fact that alphas do not penetrate the pipe walls. Unlike their conventional counterparts, alpha detectors based on ion transport technology sense alpha particles by collecting the ions created in ambient air as the particle loses its kinetic energy. The ions inside the pipe are transported by a fan-generated air current to an electrode inside the detector, which is attached to one end of the pipe. The collected charge at the electrode is proportional to the number of ions created inside the pipe, which in turn is proportional to the number of alphas emitted. Typically, monitoring for alpha contamination inside pipes or ductwork involves disrupting the operation to access as much surface area as possible for standard alpha monitoring. The detector based on ion transport technology effectively minimizes such disruption and in many circumstances will allow for in situ monitoring of a system that might otherwise not be practically accessible to standard methods.

  3. 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.

  4. 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.

  5. GTRAN- TRANSIENT ANALYSIS OF GAS PIPING SYSTEMS

    NASA Technical Reports Server (NTRS)

    TROVILLION T A

    1994-01-01

    The GTRAN program was developed to solve transient, as well as steady state, problems for gas piping systems. GTRAN capabilities allow for the analysis of a variety of system configurations and components. These include: multiple pipe junctions; valves that change position with time; fixed restrictions (orifices, manual valves, filters, etc.); relief valves; constant pressure sources; and heat transfer for insulated piping and piping subjected to free or forced convection. In addition, boundary conditions can be incorporated to simulate specific components. The governing equations of GTRAN are the one-dimensional transient gas dynamic equations. The three equations for pressure, velocity, and density are reduced to numerical equations using an implicit Crank-Nicholson finite difference technique. Input to GTRAN includes a description of the piping network, the initial conditions, and any events (e.g. valve closings) occuring during the period of analysis. Output includes pressure, velocity, and density versus time. GTRAN is written in FORTRAN 77 for batch execution and has been implemented on a DEC VAX series computer. GTRAN was developed in 1983.

  6. Arterial heat pipe performance in a transient heat flux and body force environment

    NASA Astrophysics Data System (ADS)

    Yerkes, Kirk L.; Beam, Jerry E.

    1992-10-01

    This paper reports on the effects of transient transverse and axial acceleration forces with step changes in input power on the performance of a flexible copper/water arterial heat pipe. Transient transverse accelerations were generated using a centrifuge table to simulate acceleration forces typifying high performance aircraft maneuvering. These transients consisted of step changes, steady periodic, and burst cycles in the transverse acceleration forces. Steady periodic and burst cycle transverse accelerations had frequencies of 0.01 and 0.03 Hz with peak-to-peak values of 1.1 to 9.8 g. Partial depriming of the artery, pooling of the unconstrained working fluid, and fluid sloshing were found to have a significant impact on the heat transport potential and transient behavior of the heat pipe. Repriming of the heat pipe under thermal load while being subjected to transient transverse accelerations was also demonstrated.

  7. Arterial heat pipe performance in a transient heat flux and body force environment

    SciTech Connect

    Yerkes, K.L.; Beam, J.E.

    1992-01-01

    This paper reports on the effects of transient transverse and axial acceleration forces with step changes in input power on the performance of a flexible copper/water arterial heat pipe. Transient transverse accelerations were generated using a centrifuge table to simulate acceleration forces typifying high performance aircraft maneuvering. These transients consisted of step changes, steady periodic, and burst cycles in the transverse acceleration forces. Steady periodic and burst cycle transverse accelerations had frequencies of 0.01 and 0.03 Hz with peak-to-peak values of 1.1 to 9.8 g. Partial depriming of the artery, pooling of the unconstrained working fluid, and fluid sloshing were found to have a significant impact on the heat transport potential and transient behavior of the heat pipe. Repriming of the heat pipe under thermal load while being subjected to transient transverse accelerations was also demonstrated. 22 refs.

  8. Characterization of pipes, drain lines, and ducts using the pipe explorer system

    SciTech Connect

    Cremer, C.D.; Kendrick, D.T.; Cramer, E.

    1997-05-01

    As DOE dismantles its nuclear processing facilities, site managers must employ the best means of disposing or remediating hundreds of miles of potentially contaminated piping and duct work. Their interiors are difficult to access, and in many cases even the exteriors are inaccessible. Without adequate characterization, it must be assumed that the piping is contaminated, and the disposal cost of buried drain lines can be on the order of $1,200/ft and is often unnecessary as residual contamination levels often are below free release criteria. This paper describes the program to develop a solution to the problem of characterizing radioactive contamination in pipes. The technical approach and results of using the Pipe Explorer {trademark} system are presented. The heart of the system is SEA`s pressurized inverting membrane adapted to transport radiation detectors and other tools into pipes. It offers many benefits over other pipe inspection approaches. It has video and beta/gamma detection capabilities, and the need for alpha detection has been addressed through the development of the Alpha Explorer{trademark}. These systems have been used during various stages of decontamination and decommissioning of DOE sites, including the ANL CP-5 reactor D&D. Future improvements and extensions of their capabilities are discussed.

  9. 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.

  10. 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.

  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. 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.

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

    DOEpatents

    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.

  14. 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.

  15. 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.

  16. Composite drill pipe

    SciTech Connect

    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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Bursts de raios gama

    NASA Astrophysics Data System (ADS)

    Braga, J.

    2003-02-01

    Nos últimos anos, graças principalmente aos dados obtidos pelo Compton Gamma-Ray Observatory e pelo satélite ítalo-holandês BeppoSAX, grandes avanços foram obtidos no nosso conhecimento sobre os fascinantes e enigmáticos fenômenos conhecidos por "bursts"de raios gama. Neste trabalho é feita uma revisão sobre a fenomenologia desses misteriosos objetos e são apresentados os desenvolvimentos recentes nessa área palpitante da astrofísica moderna, ressaltando tanto os resultados observacionais obtidos até o momento quanto os modelos teóricos propostos para explixá-los.

  2. 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.

  3. 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

  4. Burst Detector Sensitivity: Past, Present and Future

    NASA Technical Reports Server (NTRS)

    Band, David L.

    2005-01-01

    I compare the burst detection sensitivity of CGRO's BATSE, Swift's BAT, the GLAST Burst Monitor (GBM) and EXIST as a function of a burst s spectrum and duration. A detector's overall burst sensitivity depends on its energy sensitivity and set of accumulations times (Delta)t; these two factors shape the detected burst population. For example, relative to BATSE, the BAT s softer energy band decreases the detection rate of short, hard bursts, while the BAT s longer accumulation times increase the detection rate of long, soft bursts. Consequently, Swift is detecting long, low fluence bursts (2-3 x fainter than BATSE).

  5. Heat Pipe With Interrupted Slot

    NASA Technical Reports Server (NTRS)

    Brown, Richard F.; Kosson, Robert L.; Edelstein, Fred

    1994-01-01

    Newer version of heat pipe slot interrupted by plug or, if heat pipe is cast, by bridge of heat-pipe material cast integrally across groove. Small barrier assists in priming heat pipe. Vapor and noncondensible gas still accumulates in liquid channel at evaporator before or during startup, but barrier keeps liquid out of small part of slot at bubble. Dry part of slot allows bubble to escape into vapor channel, making room for liquid to move in during startup.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. Concept for LEU Burst Reactor

    SciTech Connect

    Klein, Steven Karl; Kimpland, Robert Herbert

    2016-03-07

    Design and performance of a proposed LEU burst reactor are sketched. Salient conclusions reached are the following: size would be ~1,500 kg or greater, depending on the size of the central cavity; internal stresses during burst require split rings for relief; the reactor would likely require multiple control and safety rods for fine control; the energy spectrum would be comparable to that of HEU machines; and burst yields and steady-state power levels will be significantly greater in an LEU reactor.

  14. The Burst of the Century

    NASA Astrophysics Data System (ADS)

    Fruchter, Andrew

    2014-09-01

    The extraordinarily bright GRB 130427A has provided a multiwavelength data set unprecedented in the history of the field. However the light curve of this burst, like that of the large majority of LAT bursts, shows a puzzling lack of a jet break (the hallmark of a collimated outflow). We propose to continue our long-term monitoring of this GRB through to the end of 2015. A detection of a jet break will give us a direct measure of the absolute energy of the burst; its absence will effectively rule out a rotating neutron star as the central engine of the GRB.

  15. A Complete Piping Analysis With Thermal Stratification Loads

    SciTech Connect

    Milton Dong; Hong Ming Lee; Chii Chern

    2002-07-01

    The U. S. Nuclear Regulatory Commission (USNRC) had issued Bulletins 88-08, 88-11, 89-90, and 93-38 to address the concerns and problems due to thermal stratification loading during the life span of normal plant operation. The thermal stratification condition typically will cause pipe to bow in on a long horizontal segment. These conditions have not been commonly considered in piping design. However, the additional thermal cyclic stresses and loads due to these conditions could lead to the fatigue damage of the piping components and the failures of pipe supports. Analyzing the effects of thermal stratification loads can be very cumbersome if it is not a built-in functionality of the analysis program. Thus in response to the recent increase in such cases we have incorporated this feature in our piping stress computer program. A stress engineer can now define the thermal stratification conditions easily and the program will compute the pipe stresses and pipe support loads automatically as one of the load cases. The program then combines the thermal stratification load cases with other load cases as required in accordance with the load histogram to determine the cumulative fatigue damage of the piping system. The thermal cyclic stresses are evaluated in accordance with the design rules of Nuclear Class 1 piping components provided in NB-3650 of ASME section III Code. This paper presents the method, modeling and validation for implementing the functionality of analyzing thermal stratification loads in a computer program, as well as an application on an actual piping system as an illustration. (authors)

  16. Detection of bursts and pauses in spike trains.

    PubMed

    Ko, D; Wilson, C J; Lobb, C J; Paladini, C A

    2012-10-15

    Midbrain dopaminergic neurons in vivo exhibit a wide range of firing patterns. They normally fire constantly at a low rate, and speed up, firing a phasic burst when reward exceeds prediction, or pause when an expected reward does not occur. Therefore, the detection of bursts and pauses from spike train data is a critical problem when studying the role of phasic dopamine (DA) in reward related learning, and other DA dependent behaviors. However, few statistical methods have been developed that can identify bursts and pauses simultaneously. We propose a new statistical method, the Robust Gaussian Surprise (RGS) method, which performs an exhaustive search of bursts and pauses in spike trains simultaneously. We found that the RGS method is adaptable to various patterns of spike trains recorded in vivo, and is not influenced by baseline firing rate, making it applicable to all in vivo spike trains where baseline firing rates vary over time. We compare the performance of the RGS method to other methods of detecting bursts, such as the Poisson Surprise (PS), Rank Surprise (RS), and Template methods. Analysis of data using the RGS method reveals potential mechanisms underlying how bursts and pauses are controlled in DA neurons.

  17. Performance characteristics of gravity-assisted, potassium heat pipes

    SciTech Connect

    Prenger, F.C.; Keddy, E.S.; Sena, J.T.

    1985-01-01

    Experiments with potassium-stainless steel gravity-assisted heat pipes were performed. Performance limitations due to entrainment or flooding of the liquid return flow are compared with analytical model predictions. The effect of heated pool height was investigated and problems with surface wetting are discussed. A comparison between entrainment limits for smooth-walled and textured-walled heat pipes was made and a minimum internal surface texturing depth is suggested.

  18. Performance characteristics of gravity-assisted potassium heat pipes

    SciTech Connect

    Prenger, F.C.; Keddy, E.S.; Sena, J.T.

    1986-08-01

    Experiments with potassium-stainless steel gravity-assisted heat pipes were performed. Performance limitations due to entrainment or flooding of the liquid return flow are compared with analytical model predictions. The effect of heated pool height was investigated, and problems with surface wetting are discussed. A comparison between entrainment limits for smoothand textured-walled heat pipes was made, and a minimum internal surface texturing depth is suggested.

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  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. Pipe ram improvement facilitates hang off

    SciTech Connect

    Not Available

    1986-06-02

    Hard facing on the top surface of ram blowout preventors (BOPs) can prevent deformation when hanging off drill pipe. A new ram body features this hardfacing. This improvement is important to floating drilling because it transfers potential damage from critical pressure components to relatively inexpensive and less critical drill pipe upsets. National Association of Corrosion Engineers (NACE) specifications for H/sub 2/S resistance often mean that pipe rams do not have the hardness required to hang off long strings without deformation to the ram. Conventionally, the problem has been solved by welding a harder material to the portion of the ram on which the tool joint lands. This method, although widely used, can result in cracking in the inlaid area of the ram. In a typical sequence, weather requires a floating drilling rig to disconnect. The pipe rams are closed after the bit is pulled off bottom. The string is lowered until a tool joint is in the rams. The drillstring is backed off, leaving downhole string weight on the rams. Upper rams are shut, and upper marine riser package, riser, and drillstring are disconnected, freeing the vessel from the well. On reentry, the operator can find that the ram bodies are damaged or the inlay is broken. This can necessitate pulling the riser for BOP stack maintenance.

  5. Ultrasonic guided wave NDE for piping

    SciTech Connect

    Rose, J.L.; Jiao, D.; Spanner, J. Jr.

    1996-11-01

    An ultrasonic guided wave nondestructive evaluation (NDE) system for rapidly detecting and quantifying the reduction in wall thickness caused by corrosion in piping under insulation is discussed. Only small, easily replaceable sections need to be removed from the thermal insulation that surrounds the pipework. The worst case scenario of the guided wave work will be a two-stage system, the first with guided waves capable of rapidly surveying the piping to indicate areas of corrosion attack and wall thinning, followed by a more quantitative technique using a more conventional normal beam ultrasonic longitudinal wave inspection. In most cases, however, the guided wave technique will be sufficient for quantitatively determining wall thickness, depending on the accuracy required and the local or global nature of the wall thinning. Drawing on guided wave experiences to date on a variety of different plate and tubing problems, preliminary feasibility experiments have already been conducted on piping under insulation in both a laboratory and a chemical processing facility field environment. Three guided wave techniques have been introduced, one on normal beam excitation, one using a broad variable angle beam transducer on a curved shoe, and a third on a newly developed pipe comb system.

  6. Extension of pipe failure models to consider the absence of data from replaced pipes.

    PubMed

    Scheidegger, Andreas; Scholten, Lisa; Maurer, Max; Reichert, Peter

    2013-07-01

    Predictions of the expected number of failures of water distribution network pipes are important to develop an optimal management strategy. A number of probabilistic pipe failure models have been proposed in the literature for this purpose. They have to be calibrated on failure records. However, common data management practices mean that replaced pipes are often absent from available data sets. This leads to a 'survival selection bias', as pipes with frequent failures are more likely to be absent from the data. To address this problem, we propose a formal statistical approach to extend the likelihood function of a pipe failure model by a replacement model. Frequentist maximum likelihood estimation or Bayesian inference can then be applied for parameter estimation. This approach is general and is not limited to a particular failure or replacement model. We implemented this approach with a Weibull-exponential failure model and a simple constant probability replacement model. Based on this distribution assumptions, we illustrated our concept with two examples. First, we used simulated data to show how replacement causes a 'survival selection bias' and how to successfully correct for it. A second example with real data illustrates how a model can be extended to consider covariables.

  7. 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.

  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. Burst interference in TDMA radio systems

    NASA Astrophysics Data System (ADS)

    Lei, Z.; Chen, M.-X.; Feher, K.

    1985-12-01

    Burst interference is inherent in TDMA subscriber radio and satellite communications systems. Spectral and interference properties of burst modulated signals are investigated. Owing to the burst mode operation of the TDMA system its spectrum spreads; this spread increases with the increase of burst gating rate and the decrease of the burst length. A theoretical derivation of the Pe = f(Eb/N0; I) performance, computer simulation and experimental results of IJF-OQPSK and conventional QPSK burst operated systems are presented. The performance of these systems in the presence of burst mode TDMA co-channel and adjacent channel interference (I) is evaluated.

  10. 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.

  11. 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.

  12. Decameter Type III-Like Bursts

    NASA Astrophysics Data System (ADS)

    Melnik, V. N.; Konovalenko, A. A.; Rutkevych, B. P.; Rucker, H. O.; Dorovskyy, V. V.; Abranin, E. P.; Lecacheux, A.; Brazhenko, A. I.; Stanislavskyy, A. A.

    2007-12-01

    Starting from 1960s Type III-like bursts (Type III bursts with high drift rates) in a wide frequency range from 300 to 950MHz have been observed. These new bursts observed at certain frequency being compared to the usual Type III bursts at the same frequency show similar behaviour but feature frequency drift 2-6 times higher than the normal bursts. In this paper we report the first observations of Type III-like bursts in decameter range, carried out during summer campaigns 2002 - 2004 at UTR-2 radio telescope. The circular polarization of the bursts was measured by the radio telescope URAN-2 in 2004. The observed bursts are analyzed and compared with usual Type III bursts in the decameter range. From the analysis of over 1100 Type III-like bursts, their main parameters have been found. Characteristic feature of the observed bursts is similar to Type III-like bursts at other frequencies, i.e. measured drift rates (5-10 MHz/s) of this bursts are few times larger than that for usual Type III bursts, and their durations (1-2 s) are few times smaller than that for usual Type III bursts in this frequency band.

  13. Coupling analysis of fluid-structure interaction in fluid-filled elbow pipe

    NASA Astrophysics Data System (ADS)

    Xu, W. W.; Wu, D. Z.; Wang, L. Q.

    2012-11-01

    Fluid in the ship pipeline, due to power equipment components (such as impellers, plungers, etc.) and valves, will induce turbulence, cavitations, which generate high-frequency vibration excitation lines. The measurements results show that fluid-induced vibration of the pipeline is not only confined to the pipeline, but also have an impact on the hull structure. Pipe vibration due to transient flow is very common in marine pipe system Thus fluid-structure interaction problems in shipping lines is being paid more and more attention. In this paper, the fluid-filled elbow pipe is simulated considering fluid-structure interaction (FSI) by the software ADINA. And the simulation results are validated through comparison with results obtained by other numerical solution. The results show that FSI affects the pipe-filled-water modal frequencies seriously, but have little effects on pipe vibration shapes, and the free vibration frequency of the fluid-filled pipe is lower than that of empty pipe. The pipe vibration amplitude and effective stress caused by fluid increase as the fluid velocity increase. Pipe continues vibrating after fluid velocity is steady, and the vibration is dispersing as time increase. The protection against vibration near the elbow is important because the maximum pipe deformation caused by fluid near the elbow. The maximum effective stress increases from 0 to 1.4MPa due to the fluid velocity increases from 0 to 20m/s in 5 seconds. So it is necessary to consider the FSI for fluid-filled pipe.

  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. 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.

  16. HETEROGENEITY IN SHORT GAMMA-RAY BURSTS

    SciTech Connect

    Norris, Jay P.; Gehrels, Neil

    2011-07-01

    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 is comprised of 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/X-Ray Telescope (XRT). The median flux of the initial XRT detections for EE bursts ({approx}6x10{sup -10} erg cm{sup -2} s{sup -1}) is {approx}>20x brighter than for non-EE bursts, and the median X-ray afterglow duration for EE bursts ({approx}60,000 s) is {approx}30x 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 denser environments than non-EE bursts, or that the sometimes-dominant EE component efficiently powers the afterglow. Combined, these results favor different progenitors for EE and non-EE short bursts.

  17. 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.

  18. Some remarks about x-ray burst sources

    SciTech Connect

    Lewin, W.H.G.

    1984-05-26

    The properties of X-ray burst sources (XRB) have recently been reviewed in great detail by Lewin and Joss (1983). Here, I will only mention some of the salient features, and I will then discuss some recent developments and some remaining problems.

  19. In vacuum thermal characteristics of different geometry sodium heat pipes

    NASA Astrophysics Data System (ADS)

    Fujiwara, Tsutomu; Ogiwara, Sachio; Nakamura, Yoshihiro; Eguchi, Kunihisa

    An experimental investigation is presently under way at the National Aerospace Laboratory (NAL) to provide understanding of high temperature heat pipe (HP) operations in space that are capable of transferring thermal energy from a solar receiver to a Stirling engine. To design a high performance heat pipe, it is necessary to assess accurately fundamental physical phenomena during the HP operations. In considering the heat pipe integration with a Stirling engine heater head, however, we are facing some problems of the HP design involved in the complex structure. Additionally, in such HP operations, the heat input distribution might be non-uniform and the liquid sodium return flow will be blocked at the connecting part of the wick. This will result in reduction of the heat transfer capability. To overcome such an operational problem, we have designed and tested two different types of heat pipe models. One is a T-shaped heat pipe and another is a cavity type, both having adiabatic and condenser parts of a single straight pipe. In the present paper, some experimental results available from these heating tests in a vacuum chamber are described.

  20. 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.

  1. Radiation crosslinked plasticized PVC - pipes

    NASA Astrophysics Data System (ADS)

    Hell, Z.; Ravlić, M.; Bogdanović, Lj.; Maleš, J.; Dvornik, I.; Ranogajec, F.; Ranogajec, M.; Tudorić-Ghemo, J.

    The efficiency of polyfunctional monomers triallyl cyanurate, allyl methacrylate, diallyl phtalate, 2-ethyl-2(hydroxy-methyl)-propanediol-(1,3) trimethacrylate, divinyl benzene and ethylene glycol dimethacrylate in radiation crosslinking of PVC was investigated. Patterns of pipes were produced and irradiated with gamma rays. The resistance to internal pressure of crosslinked PVC pipes was measured at 80°C and compared with resistance of unirradiated PVC pipes.

  2. 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.

  3. 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.

  4. 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.

  5. Amplitude-Modulated Bursting: A Novel Class of Bursting Rhythms

    NASA Astrophysics Data System (ADS)

    Vo, Theodore; Kramer, Mark A.; Kaper, Tasso J.

    2016-12-01

    We report on the discovery of a novel class of bursting rhythms, called amplitude-modulated bursting (AMB), in a model for intracellular calcium dynamics. We find that these rhythms are robust and exist on open parameter sets. We develop a new mathematical framework with broad applicability to detect, classify, and rigorously analyze AMB. Here we illustrate this framework in the context of AMB in a model of intracellular calcium dynamics. In the process, we discover a novel family of singularities, called toral folded singularities, which are the organizing centers for the amplitude modulation and exist generically in slow-fast systems with two or more slow variables.

  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 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

  8. Deployable Pipe-Z

    NASA Astrophysics Data System (ADS)

    Zawidzki, Machi

    2016-10-01

    This paper presents a concept of deployable Pipe-Z (dPZ): a modular structural system which takes advantage of the robustness of rigid-panel mechanism and allows to create free-form links which are also reconfigurable and deployable. The concept presented can be applied for building habitats and infrastructures for human exploration of oceans and outer space. dPZ structures can adapt to changing requirements e.g. mission objectives, crew condition and technological developments. Furthermore, such lightweight and adaptable structural concept can assist in sustainable exploration development. After brief introduction, the concept of Pipe-Z (PZ) is presented. Next, the reconfigurability of PZ is explained and illustrated with continuous and collision-free transition from a PZ forming a Trefoil knot to a Figure-eight knot. The following sections introduce, explain and illustrate the folding mechanism of a single foldable Pipe-Z module (fPZM) and entire dPZ structure. The latter is illustrated with asynchronous (delayed) unfolding of a relatively complex Unknot. Several applications of PZ are suggested, namely for underwater and deep-space and surface habitats, for permanent, but in particular, temporary or emergency passages. As an example, a scenario of a failure of one of the modules of the International Space Station is presented where a rigid structure of 40 fPZMs bypasses the "dead link". A low-fidelity prototype of a 6-module octagonal dPZ is presented; several folding schemes including concentric toric rings are demonstrated. Practical issues of pressurization and packing are briefly discussed.

  9. The Swift Burst Alert Telescope

    NASA Astrophysics Data System (ADS)

    Parsons, A.; Barthelmy, S.; Barbier, L.; Gehrels, N.; Palmer, D.; Tueller, J.; Fenimore, E.; BAT Engineering Team

    2000-10-01

    The Swift Gamma Ray Burst MIDEX is a multiwavelength observatory scheduled to be launched in September 2003 to study gamma-ray bursts (GRBs) and their x-ray and optical afterglow emission. Swift will exploit these newly discovered GRB afterglow characteristics to make a comprehensive study of ~ 1000 GRBs and use the afterglow phenomenon as a tool for probing their source and evolution. Swift will also be able to use GRBs to probe the early Universe. The Burst Alert Telescope (BAT), a large coded aperture instrument with a wide field-of-view (FOV), provides the gamma-ray burst triggers and locations for the Swift Mission. BAT will observe and locate hundreds of bursts per year to better than 4 arc minutes accuracy. Using this prompt burst location information, Swift can slew quickly (within 20 - 70 s) to point on-board x-ray (XRT) and optical (UVOT) instrumentation at the burst for continued afterglow studies. The BAT instrument consists of a large (5200 cm2) hard x-ray detector plane positioned one meter away from an even larger (2.6 m2) coded aperture mask. The BAT detector plane consists of 128 CdZnTe semiconductor detector modules each containing 256 individual, planar 4 mm x 4 mm x 2 mm CdZnTe detectors that are read out by a pair of XA1 Application Specific Integrated Circuits (ASICs). The BAT mask will be constructed using 5 mm x 5 mm x 1 mm lead tiles attached to a self-supporting 0.4 g/cm2 substrate fabricated from Kevlar fiber/honeycomb materials. With 4 mm square focal plane detector elements and 5 mm square mask pixels, BAT will have angular resolution better than 22 arc minutes and will determine GRB source locations to ~ 4 arc minutes for bursts detected at 5 sigma or brighter. A full description of the BAT instrument and its capabilities will be presented along with results from performance tests of prototype detector modules.

  10. 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.

  11. Polymeric heat pipe wick

    NASA Astrophysics Data System (ADS)

    Seidenberg, Benjamin

    1988-08-01

    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.

  12. Resource Sharing Controls Gene Expression Bursting.

    PubMed

    Caveney, Patrick M; Norred, S Elizabeth; Chin, Charles W; Boreyko, Jonathan B; Razooky, Brandon S; Retterer, Scott T; Collier, C Patrick; Simpson, Michael L

    2017-02-17

    Episodic gene expression, with periods of high expression separated by periods of no expression, is a pervasive biological phenomenon. This bursty pattern of expression draws from a finite reservoir of expression machinery in a highly time variant way, i.e., requiring no resources most of the time but drawing heavily on them during short intense bursts, that intimately links expression bursting and resource sharing. Yet, most recent investigations have focused on specific molecular mechanisms intrinsic to the bursty behavior of individual genes, while little is known about the interplay between resource sharing and global expression bursting behavior. Here, we confine Escherichia coli cell extract in both cell-sized microfluidic chambers and lipid-based vesicles to explore how resource sharing influences expression bursting. Interestingly, expression burst size, but not burst frequency, is highly sensitive to the size of the shared transcription and translation resource pools. The intriguing implication of these results is that expression bursts are more readily amplified than initiated, suggesting that burst formation occurs through positive feedback or cooperativity. When extrapolated to prokaryotic cells, these results suggest that large translational bursts may be correlated with large transcriptional bursts. This correlation is supported by recently reported transcription and translation bursting studies in E. coli. The results reported here demonstrate a strong intimate link between global expression burst patterns and resource sharing, and they suggest that bursting plays an important role in optimizing the use of limited, shared expression resources.

  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. Building a Copper Pipe "Xylophone."

    ERIC Educational Resources Information Center

    Lapp, David R.

    2003-01-01

    Explains how to use the equation for frequency of vibration of a transversely oscillating bar or pipe with both ends free to vibrate to build a simple and inexpensive xylophone from a 3-meter section of copper pipe. The instrument produces a full major scale and can be used to investigate various musical intervals. (Author/NB)

  15. Heat Pipe Thermal Conditioning Panel

    NASA Technical Reports Server (NTRS)

    Saaski, E. W.

    1973-01-01

    The development, fabrication, and evaluation of heat pipe thermal conditioning panels are discussed. The panels were designed and fabricated to be compatible with several planned NASA space vehicles, in terms of panel size, capacity, temperature gradients, and integration with various heat exchangers and electronic components. It was satisfactorily demonstrated that the heat pipe thermal conditioning panel meets the thermal efficiency and heat transport requirements.

  16. Pipe crawler with stabilizing midsection

    DOEpatents

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

    1994-12-27

    A pipe crawler is described having a midsection that provides the stability and flexibility to allow the pipe crawler to negotiate curved and uneven segments of piping while traveling through piping systems. The pipe crawler comprises a front leg assembly, a rear leg assembly, a midsection with a gimbal at each end for connecting the midsection to the front and rear leg assemblies in a flexible manner, and an air cylinder for changing the distance between the front and rear leg assemblies. The pipe crawler moves in ''inch worm'' fashion with the front and rear leg assemblies alternating between an extended and a retracted position as the air cylinder moves the retracted leg assembly forward. The midsection has a plurality of legs extending radially for holding the midsection within a maximum displacement from the piping axis so that the gimbals are not pivoted to extreme angles where they might lock up or seize. When the midsection is displaced sufficiently, its legs with wheels on each end engage the interior surface of the piping and prevent further displacement. Using two gimbals divides the angle between the planes defined by the front and rear leg assemblies which also helps to prevent excessive gimbal pivoting. 5 figures.

  17. Pipe crawler with stabilizing midsection

    DOEpatents

    Zollinger, William T.; Treanor, Richard C.

    1994-01-01

    A pipe crawler having a midsection that provides the stability and flexibty to allow the pipe crawler to negotiate curved and uneven segments of piping while traveling through piping systems. The pipe crawler comprises a front leg assembly, a rear leg assembly, a midsection with a gimbal at each end for connecting the midsection to the front and rear leg assemblies in a flexible manner, and an air cylinder for changing the distance between the front and rear leg assemblies. The pipe crawler moves in "inch worm" fashion with the front and rear leg assemblies alternating between an extended and a retracted position as the air cylinder moves the retracted leg assembly forward. The midsection has a plurality of legs extending radially for holding the midsection within a maximum displacement from the piping axis so that the gimbals are not pivoted to extreme angles where they might lock up or seize. When the midsection is displaced sufficiently, its legs with wheels on each end engage the interior surface of the piping and prevent further displacement. Using two gimbals divides the angle between the planes defined by the front and rear leg assemblies which also helps to prevent excessive gimbal pivoting.

  18. Alternate high capacity heat pipe

    NASA Technical Reports Server (NTRS)

    Voss, F. E.

    1986-01-01

    The performance predictions for a fifty foot heat pipe (4 foot evaporator - 46 foot condensor) are discussed. These performance predictions are supported by experimental data for a four foot heat pipe. Both heat pipes have evaporators with axial groove wick structures and condensers with powder metal external artery wick structures. The predicted performance of a rectangular axial groove/external artery heat pipe operating in space is given. Heat transport versus groove width is plotted for 100, 200 and 300 grooves in the evaporator. The curves show that maximum power is achieved for groove widths from 0.040 to 0.053 as the number of grooves varies from 300 to 100. The corresponding range of maximum power is 3150 to 2400 watts. The relationships between groove width and heat pipe evaporate diameter for 100, 200 and 300 grooves in the evaporator are given. A four foot heat pipe having a three foot condenser and one foot evaporator was built and tested. The evaporator wick structure used axial grooves with rectangular cross sections, and the condenser wick structure used powder metal with an external artery configuration. Fabrication drawings are enclosed. The predicted and measured performance for this heat pipe is shown. The agreement between predicted and measured performance is good and therefore substantiates the predicted performance for a fifty foot heat pipe.

  19. Demonstrating Sound Impulses in Pipes.

    ERIC Educational Resources Information Center

    Raymer, M. G.; Micklavzina, Stan

    1995-01-01

    Describes a simple, direct method to demonstrate the effects of the boundary conditions on sound impulse reflections in pipes. A graphical display of the results can be made using a pipe, cork, small hammer, microphone, and fast recording electronics. Explains the principles involved. (LZ)

  20. Water flows from slotted pipes

    SciTech Connect

    Olson, D.A.

    1981-04-01

    Results of experiments and analyses that determine jet flow distribution from slotted pipes of dimensions typical for OC-OTEC evaporators or condensers are described. For a pipe with a 6.3-cm inside diameter and 0.64-cm wide slot, the measured and predicted jet flow was low and nearly parallel to the pipe at the entrance, and high and perpendicular to the pipe only near the closed end. Slot lengths ranged from 1.5 m to 4.6 m, and inlet flow rates varied from 6 kg/s to 17 kg/s. Friction reduces the pressure in the entrance and intermediate portions of the pipe, while the rapidly decelerating flow produces high pressure recovery as it approaches the closed end. In the region of high flow next to the closed end, the ratio of slot area (slot length times width) to pipe cross-sectional area is less than two. To use a slotted pipe for generating falling jets in an OC-OTEC plant, the slot length should be 1 m or less (for a pipe with a 6.3-cm inside diameter and a 0.64-cm wide slot).

  1. Heat Pipe Blocks Return Flow

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.

    1982-01-01

    Metal-foil reed valve in conventional slab-wick heat pipe limits heat flow to one direction only. With sink warmer than source, reed is forced closed and fluid returns to source side through annular transfer wick. When this occurs, wick slab on sink side of valve dries out and heat pipe ceases to conduct heat.

  2. Model changes improve compressor-station piping pressure-loss predictions

    SciTech Connect

    Meyer, T.R.

    1985-04-29

    This article explains steps taken to modify loss calculations to predict more accurately pressure losses in the station piping systems of Texas Gas. The article does not attempt to set any industry standards for determining pressure drop in station piping. Its purposes are to point out that problems exist in current methods used for calculating station piping pressure losses, to show that manufacturer estimates of pressure drop may not always reflect actual conditions, and to outline the procedure used by Texas Gas to model more accurately compressor station piping.

  3. 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

  4. Vapor spill pipe monitor

    DOEpatents

    Bianchini, G.M.; McRae, T.G.

    1983-06-23

    The invention is a method and apparatus for continually monitoring the composition of liquefied natural gas flowing from a spill pipe during a spill test by continually removing a sample of the LNG by means of a probe, gasifying the LNG in the probe, and sending the vaporized LNG to a remote ir gas detector for analysis. The probe comprises three spaced concentric tubes surrounded by a water jacket which communicates with a flow channel defined between the inner and middle, and middle and outer tubes. The inner tube is connected to a pump for providing suction, and the probe is positioned in the LNG flow below the spill pipe with the tip oriented partly downward so that LNG is continuously drawn into the inner tube through a small orifice. The probe is made of a high thermal conductivity metal. Hot water is flowed through the water jacket and through the flow channel between the three tubes to provide the necessary heat transfer to flash vaporize the LNG passing through the inner channel of the probe. The gasified LNG is transported through a connected hose or tubing extending from the probe to a remote ir sensor which measures the gas composition.

  5. Geothermal district piping - A primer

    SciTech Connect

    Rafferty, K.

    1989-11-01

    Transmission and distribution piping constitutes approximately 40 -60% of the capital costs of typical geothermal district heating systems. Selections of economical piping suitable for the fluid chemistry is critical. Presently, most piping (56%) in geothermal systems is of asbestos cement construction. Some fiberglass (19%) and steel (19%) is also in use. Identification of an economical material to replace asbestos cement is important to future project development. By providing information on relative costs, purchase considerations, existing material performance and new products, this report seeks to provide a background of information to the potential pipe purchaser. A brief discussion of the use of uninsulated piping in geothermal district heating systems is also provided. 5 refs., 19 figs., 1 tab.

  6. Prometheus Hot Leg Piping Concept

    NASA Astrophysics Data System (ADS)

    Gribik, Anastasia M.; DiLorenzo, Peter A.

    2007-01-01

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  7. Promethus Hot Leg Piping Concept

    SciTech Connect

    AM Girbik; PA Dilorenzo

    2006-01-24

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  8. Flexible ultrasonic pipe inspection apparatus

    DOEpatents

    Jenkins, Charles F.; Howard, Boyd D.

    1998-01-01

    A flexible, modular ultrasonic pipe inspection apparatus, comprising a flexible, hollow shaft that carries a plurality of modules, including at least one rotatable ultrasonic transducer, a motor/gear unit, and a position/signal encoder. The modules are connected by flexible knuckle joints that allow each module of the apparatus to change its relative orientation with respect to a neighboring module, while the shaft protects electrical wiring from kinking or buckling while the apparatus moves around a tight corner. The apparatus is moved through a pipe by any suitable means, including a tether or drawstring attached to the nose or tail, differential hydraulic pressure, or a pipe pig. The rotational speed of the ultrasonic transducer and the forward velocity of the apparatus are coordinated so that the beam sweeps out the entire interior surface of the pipe, enabling the operator to accurately assess the condition of the pipe wall and determine whether or not leak-prone corrosion damage is present.

  9. Prometheus Hot Leg Piping Concept

    SciTech Connect

    Gribik, Anastasia M.; DiLorenzo, Peter A.

    2007-01-30

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  10. Effects of Stormwater Pipe Size and Rainfall on Sediment and Nutrients Delivered to a Coastal Bayou

    EPA Science Inventory

    Pollutants discharged from stormwater pipes can cause water quality and ecosystem problems in coastal bayous. A study was conducted to characterize sediment and nutrients discharged by small and large (, 20 cm and .20 cm in internal diameters, respectively) pipes under different ...

  11. WATER QUALITY AND TREATMENT CONSIDERATIONS FOR CEMENT-LINED AND A-C PIPE

    EPA Science Inventory

    Both cement mortar lined (CML) and asbestos-cement pipes (A-C) are widely used in many water systems. Cement linings are also commonly applied in-situ after pipe cleaning, usually to prevent the recurrence of red water or tuberculation problems. Unfortunately, little consideratio...

  12. Computer program grade for design and analysis of graded-porosity heat-pipe wicks

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.

    1974-01-01

    A computer program for numerical solution of differential equations that describe heat pipes with graded-porosity fibrous wicks is discussed. A mathematical problem is provided with a summary of the input and output steps used to solve it. The program is also applied to the analysis of a typical heat pipe.

  13. Internal erosion during soil pipe flow: Role in gully erosion and hillslope instability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many field observations have lead to speculation on the role of piping in embankment failures, landslides, and gully erosion. However, there has not been a consensus on the subsurface flow and erosion processes involved and inconsistent use of terms have exasperated the problem. One such piping proc...

  14. Fracture mechanics models developed for piping reliability assessment in light water reactors: piping reliability project

    SciTech Connect

    Harris, D.O.; Lim, E.Y.; Dedhia, D.D.; Woo, H.H.; Chou, C.K.

    1982-06-01

    The efforts concentrated on modifications of the stratified Monte Carlo code called PRAISE (Piping Reliability Analysis Including Seismic Events) to make it more widely applicable to probabilistic fracture mechanics analysis of nuclear reactor piping. Pipe failures are considered to occur as the result of crack-like defects introduced during fabrication, that escape detection during inspections. The code modifications allow the following factors in addition to those considered in earlier work to be treated: other materials, failure criteria and subcritical crack growth characteristic; welding residual and vibratory stresses; and longitudinal welds (the original version considered only circumferential welds). The fracture mechanics background for the code modifications is included, and details of the modifications themselves provided. Additionally, an updated version of the PRAISE user's manual is included. The revised code, known as PRAISE-B was then applied to a variety of piping problems, including various size lines subject to stress corrosion cracking and vibratory stresses. Analyses including residual stresses and longitudinal welds were also performed.

  15. An investigation of corrosion in liquid-metal heat pipes

    SciTech Connect

    Adkins, D.R.; Rawlinson, K.S.; Andraka, C.E.; Showalter, S.K.; Moreno, J.B.; Moss, T.A.; Cordiero, P.G.

    1998-08-01

    Research is underway to develop a 75-kW heat pipe to transfer solar energy from the focus of a parabolic dish concentrator to the heater tubes of a Stirling engine. The high flux levels and high total power level encountered in this application have made it necessary to use a high-performance wick structure with fibers on the order of 4 to 8 microns in diameter. This fine wick structure is highly susceptible to corrosion damage and plugging, as dissolved contaminants plate out on the evaporator surface. Normal operation of the heat pipe also tends to concentrate contaminants in localized areas of the evaporator surface where heat fluxes are the highest. Sandia National Laboratories is conducting a systematic study to identify procedures that reduce corrosion and contamination problems in liquid-metal heat pipes. A series of heat pipes are being tested to explore different options for cleaning heat-pipe systems. Models are being developed to help understand the overall importance of operating parameters on the life of heat-pipe systems. In this paper, the authors present their efforts to reduce corrosion damage.

  16. Monitoring pipe line stress due to ground displacement

    SciTech Connect

    Greenwood, J.H. Jr.

    1986-04-01

    Northwest Pipeline Corp. has a large-diameter natural gas pipe line system from Ignacio, Colo., to Sumas, Wash. At Douglas Pass in Colorado, large landslides required several sections of the line to be relocated outside the slide areas: 4,400 ft of new line in April 1962 and 3,200 ft in March 1963. No serious disruptions occurred for the next 16 years. Then in July 1979, some 1,200 ft had to be relocated. From 1980 to date, many landslides in the Douglas Pass area have caused new deformations, with the springs of 1983 and 1984 being the worst years. In 1980, Northwest Pipeline began engineering and geotechnical studies of the landslide problems. These led to instrumentation and pipe monitoring which indicated that pipe failure can be predicted and prevented if important slope deformations or increases in pipe stresses are detected early enough to implement some mitigating measures. Excavation of the pipe to relieve the stresses was used in most cases. The method was so successful that no pipe failure occurred in 1984 within instrumented sections, in spite of the exceptionally bad climatic conditions experienced.

  17. Gamma-ray burst observations

    NASA Technical Reports Server (NTRS)

    Atteia, J.-L.

    1993-01-01

    The most important observational characteristics of gamma-ray bursts are reviewed, with emphasis on X-ray and gamma-ray data. The observations are used to derive some basic properties of the sources. The sources are found to be isotropically distributed; the burster population is limited in space, and the edge of the distribution is visible.

  18. Respiratory burst oxidase of fertilization.

    PubMed Central

    Heinecke, J W; Shapiro, B M

    1989-01-01

    Partially reduced oxygen species are toxic, yet sea urchin eggs synthesize H2O2 in a "respiratory burst" at fertilization, as an extracellular oxidant to crosslink their protective surface envelopes. To study the biochemical mechanism for H2O2 production, we have isolated an NADPH-specific oxidase fraction from homogenates of unfertilized Strongylocentrotus purpuratus eggs that produces H2O2 when stimulated with Ca2+ and MgATP2-. Concentrations of free Ca2+ previously implicated in regulation of egg activation modulate the activity of the oxidase. Inhibitors were used to test the relevance of this oxidase to the respiratory burst of fertilization. Procaine, two phenothiazines, and N-ethylmaleimide (but not iodoacetamide) inhibited H2O2 production by the oxidase fraction and oxygen consumption by activated eggs. The ATP requirement suggested that protein kinase activity might regulate the respiratory burst of fertilization; consonant with this hypothesis, H-7 and staurosporine were inhibitory. The respiratory burst oxidase of fertilization is an NADPH:O2 oxidoreductase that appears to be regulated by a protein kinase; although it bears a remarkable resemblance to the neutrophil oxidase, unlike the latter it does not form O2- as its initial product. PMID:2537493

  19. The Mystery of Gamma-Ray Bursts

    NASA Technical Reports Server (NTRS)

    Fishman, Gerald J.

    1998-01-01

    Gamma-ray bursts remain on of the greatest mysteries in astrophysics in spite of recent observational advances and intense theoretical work. Although some of the basic properties of bursts were known 25 years ago, new and more detailed observations have been made by the BATSE (Burst and Transient Source Experiment) experiment on the Compton Gamma Ray Observatory in the past five years. Recent observations of bursts and some proposed models will be discussed.

  20. The influences of soil and nearby structures on dispersion characteristics of wave propagating along buried plastic pipes

    NASA Astrophysics Data System (ADS)

    Liu, Shuyong; Jiang, J.; Parr, Nicola

    2016-09-01

    Water loss in distribution systems is a global problem for the water industry and governments. According to the international water supply association (IWSA), as a result of leaks from distribution pipes, 20% to 30% of water is lost while in transit from treatment plants to consumers. Although governments have tried to push the water industry to reduce the water leaks, a lot of experts have pointed out that a wide use of plastic pipes instead of metal pipes in recent years has caused difficulties in the detection of leaks using current acoustic technology. Leaks from plastic pipes are much quieter than traditional metal pipes and comparing to metal pipes the plastic pipes have very different coupling characteristics with soil, water and surrounding structures, such as other pipes, road surface and building foundations. The dispersion characteristics of wave propagating along buried plastic pipes are investigated in this paper using finite element and boundary element based models. Both empty and water- filled pipes were considered. Influences from nearby pipes and building foundations were carefully studied. The results showed that soil condition and nearby structures have significant influences on the dispersion characteristics of wave propagating along buried plastic pipes.

  1. Precipitation dendrites in turbulent pipe flows

    NASA Astrophysics Data System (ADS)

    Angheluta, Luiza; Hawkins, Christopher; Hammer, Øyvind; Jamtveit, Bjørn

    2013-04-01

    Surface precipitation in pipelines, as well as freezing in water pipes is of great concern in many industrial applications where scaling phenomena becomes a control problem of pipe-clogging or an efficiency reduction in transport. Flow blockage often occurs even when only a small fraction is deposited non-uniformly on the walls in the form of dendrites. Dendritic patterns are commonly encountered in surface precipitation from supersaturated solutions, e.g. calcite dendrites, as well as in solidification from undercooled liquids, e.g. freezing of water into ice dendrites. We explore the mathematical similarities between precipitation and freezing processes and, in particular, investigate the effect of fluid flow on the precipitation dendrites on pipe walls. We use a phase field approach to model surface growth coupled with a lattice Boltzmann method that simulates a channel flow at varying Reynolds number. The dendrites orientation and shape depend non-trivially on the ratio between advection and diffusion, i.e. the Peclet number, as well as the Reynolds number. Roughness induced vortices near growing dendrites at high flow rates further affect the branch splitting of dendrites. We show how the transport rate in a pipeline may depend on the different dendritic morphologies, and provide estimates for the flow conditions that correspond to most efficient transport regimes.

  2. Burst Mode Receiver for 112 Gb/s DP-QPSK with parallel DSP.

    PubMed

    Thomsen, Benn C; Maher, Robert; Millar, David S; Savory, Seb J

    2011-12-12

    A burst mode 112 Gb/s DP-QPSK digital coherent optical receiver with parallel DSP suitable for implementation in a CMOS ASIC with a 218.75 MHz clock speed is presented. The receiver performance is validated in a five channel 50 GHz grid WDM burst switching experiment using a commercially available wavelength tunable laser as the local oscillator. A new equalizer initialization scheme that overcomes the degenerate convergence problem and ensures rapid convergence is introduced. We show that the performance of the tunable local oscillator is commensurate with burst mode coherent reception when differential decoding in employed and that required parallel DSP implementation does not seriously impair the polarization and frequency tracking performance of a digital coherent receiver under burst mode operation. We report a burst acquisition time of less than 200 ns.

  3. Quantitative prediction of reduction in large pipe setting round process

    NASA Astrophysics Data System (ADS)

    Zhao, Jun; Zhan, Peipei; Ma, Rui; Zhai, Ruixue

    2013-07-01

    The control manner during the process to ensure the quality of pipe products mainly relies on the operator's experience, so it is very necessary to study the setting round process and obtain its spring-back law. The setting round process is shaping an oval section pipe into circular section, so it is difficult to provide a quantificational analysis for its spring-back process because of the curvature inequality of pipe section neutral layer. However, the spring-back law of the circle-oval process can be easily predicted. The experimental method is firstly used to establish the equivalent effect between the setting round process and the circle-oval process. The setting round process can be converted into the circle-oval process. There are two difficulties in the theoretical analysis for the circle-oval process: elastic-plastic bending problem of curved beam; statically indeterminate problem. A quantitative analytic method for the circle-oval process is presented on the basis of combination of the spring-back law of plane curved beam with the element dividing idea in finite element method. The ovality after unloading versus the relative reduction is plotted with analytical and experimental results respectively, which shows a fair agreement. Finally, the method of quantitative prediction of reduction for large pipe setting round is given based on the equivalent effect and the analytical results. Five pipes, which are needed to be set round, are used to carry out experiment so as to verify this method. The results of verification experiment indicates that, in the experimental range, the residual ovality are all under 0.35% after the once only setting round with the theoretical prediction reductions. It is much less than the 1% requirement of pipe standard. Applying the established theoretical analysis is able to correct the pipe ovality with sufficient accuracy, which provides theoretical direction to plant use.

  4. Plastic pipe insertion

    SciTech Connect

    Diskin, J.

    1987-05-01

    In March 1987 KPL changed all that when the utility inserted 1,000 ft of 16-in. SDR 15.5 Phillips Driscopipe 8000 pipe with a wall thickness of 1.032-in., into an abandoned 24-in. cast-iron line in downtown Kansas City. This is believed to be the largest diameter insert removal job ever done for gas distribution in the U.S. For KPL it was a natural progression from the smaller sizes used earlier. The procedure is the same, and the operation was quick and comparatively simple. Lower construction costs were the bottom line because with insert renewal there is no need to cut up the streets, a major expense in any urban pipeline work. There are other significant costs savings as well because the insert renewal construction process is faster than other techniques.

  5. The Mystery of Gamma-Ray Bursts

    NASA Technical Reports Server (NTRS)

    Fishman, Gerald J.

    2004-01-01

    Gamma-ray bursts remain one of the greatest mysteries in astrophysics. Observations of gamma-ray bursts made by the BATSE experiment on the Compton Gamma-Ray Observatory will be described. Most workers in the field now believe that they originate from cosmological distances. This view has been reinforced by observations this year of several optical afterglow counterparts to gamma-ray bursts. A summary of these recent discoveries will be presented, along with their implications for models of the burst emission mechanism and the energy source of the bursts.

  6. Heat pipe technology: A biblography with abstracts

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A bibliography of heat pipe research and development projects conducted during April through June 1972, is presented. The subjects discussed are: (1) general information, (2) heat pipe applications, (3) heat pipe theory, (4) design and fabrication, (5) test and operation, (6) subject and author index, and (7) heat pipe related patents.

  7. Leachate storage transport tanker loadout piping

    SciTech Connect

    Whitlock, R.W.

    1994-11-18

    This report shows the modifications to the W-025 Trench No. 31 leachate loadout discharge piping, and also the steps involved in installing the discharge piping, including dimensions and welding information. The installation of the discharge pipe should be done in accordance to current pipe installation standards. Trench No. 31 is a radioactive mixed waste land disposal facility.

  8. 46 CFR 45.133 - Air pipes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Air pipes. 45.133 Section 45.133 Shipping COAST GUARD....133 Air pipes. (a) Where an air pipe to any tank extends above the freeboard or superstructure deck— (1) The exposed part of the air pipe must be made of steel and of sufficient thickness to...

  9. 46 CFR 45.133 - Air pipes.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Air pipes. 45.133 Section 45.133 Shipping COAST GUARD....133 Air pipes. (a) Where an air pipe to any tank extends above the freeboard or superstructure deck— (1) The exposed part of the air pipe must be made of steel and of sufficient thickness to...

  10. 46 CFR 76.23-20 - Piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... System, Details § 76.23-20 Piping. (a) All piping, valves, and fittings shall meet the applicable requirements of subchapter F (Marine Engineering) of this chapter. (b) All piping, valves, and fittings of... the Commandant. (c) All piping, valves, fittings, and sprinkler heads shall be securely supported,...

  11. Determination of Secondary Encasement Pipe Design Pressure

    SciTech Connect

    TEDESCHI, A.R.

    2000-10-26

    This document published results of iterative calculations for maximum tank farm transfer secondary pipe (encasement) pressure upon failure of the primary pipe. The maximum pressure was calculated from a primary pipe guillotine break. Results show encasement pipeline design or testing pressures can be significantly lower than primary pipe pressure criteria.

  12. 49 CFR 192.281 - Plastic pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Plastic pipe. 192.281 Section 192.281... Plastic pipe. (a) General. A plastic pipe joint that is joined by solvent cement, adhesive, or heat fusion may not be disturbed until it has properly set. Plastic pipe may not be joined by a threaded joint...

  13. 49 CFR 192.281 - Plastic pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Plastic pipe. 192.281 Section 192.281... Plastic pipe. (a) General. A plastic pipe joint that is joined by solvent cement, adhesive, or heat fusion may not be disturbed until it has properly set. Plastic pipe may not be joined by a threaded joint...

  14. 49 CFR 192.281 - Plastic pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Plastic pipe. 192.281 Section 192.281... Plastic pipe. (a) General. A plastic pipe joint that is joined by solvent cement, adhesive, or heat fusion may not be disturbed until it has properly set. Plastic pipe may not be joined by a threaded joint...

  15. 49 CFR 192.281 - Plastic pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Plastic pipe. 192.281 Section 192.281... Plastic pipe. (a) General. A plastic pipe joint that is joined by solvent cement, adhesive, or heat fusion may not be disturbed until it has properly set. Plastic pipe may not be joined by a threaded joint...

  16. 49 CFR 192.281 - Plastic pipe.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Plastic pipe. 192.281 Section 192.281... Plastic pipe. (a) General. A plastic pipe joint that is joined by solvent cement, adhesive, or heat fusion may not be disturbed until it has properly set. Plastic pipe may not be joined by a threaded joint...

  17. 49 CFR 192.55 - Steel pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Steel pipe. 192.55 Section 192.55 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.55 Steel pipe. (a) New steel pipe is... in accordance with paragraph (c) or (d) of this section. (b) Used steel pipe is qualified for...

  18. 49 CFR 192.55 - Steel pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Steel pipe. 192.55 Section 192.55 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.55 Steel pipe. (a) New steel pipe is... in accordance with paragraph (c) or (d) of this section. (b) Used steel pipe is qualified for...

  19. 49 CFR 192.55 - Steel pipe.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Steel pipe. 192.55 Section 192.55 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.55 Steel pipe. (a) New steel pipe is... in accordance with paragraph (c) or (d) of this section. (b) Used steel pipe is qualified for...

  20. 49 CFR 192.55 - Steel pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Steel pipe. 192.55 Section 192.55 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.55 Steel pipe. (a) New steel pipe is... in accordance with paragraph (c) or (d) of this section. (b) Used steel pipe is qualified for...

  1. 49 CFR 192.55 - Steel pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Steel pipe. 192.55 Section 192.55 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.55 Steel pipe. (a) New steel pipe is... in accordance with paragraph (c) or (d) of this section. (b) Used steel pipe is qualified for...

  2. 46 CFR 108.475 - Piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Extinguishing Systems Foam Extinguishing Systems § 108.475 Piping. (a) Each pipe, valve, and fitting in a foam... pipe, valve, and fitting must have support and protection from damage. (d) Each foam extinguishing... to remove liquid from the system. (e) Piping in a foam extinguishing system must be used only...

  3. Heat pipe technology: A bibliography with abstracts

    NASA Technical Reports Server (NTRS)

    1971-01-01

    A cumulative bibliography on heat pipe research and development projects is presented. The subjects discussed are: (1) general information, (2) heat pipe applications, (3) heat pipe theory, (4) design and fabrication, (5) testing and operation, (6) subject and author index, and (7) heat pipe related patents.

  4. 49 CFR 192.279 - Copper pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Copper pipe. 192.279 Section 192.279 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Copper pipe. Copper pipe may not be threaded except that copper pipe used for joining screw fittings...

  5. 49 CFR 192.279 - Copper pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Copper pipe. 192.279 Section 192.279 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Copper pipe. Copper pipe may not be threaded except that copper pipe used for joining screw fittings...

  6. 49 CFR 192.279 - Copper pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Copper pipe. 192.279 Section 192.279 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Copper pipe. Copper pipe may not be threaded except that copper pipe used for joining screw fittings...

  7. 49 CFR 192.279 - Copper pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Copper pipe. 192.279 Section 192.279 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Copper pipe. Copper pipe may not be threaded except that copper pipe used for joining screw fittings...

  8. 49 CFR 192.279 - Copper pipe.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Copper pipe. 192.279 Section 192.279 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Copper pipe. Copper pipe may not be threaded except that copper pipe used for joining screw fittings...

  9. Influence of gravity on flutter of cantilevered pipes conveying fluid

    NASA Astrophysics Data System (ADS)

    Rivero, Javier; Perez-Saborid, Miguel

    2012-11-01

    We have considered the dynamics of the nonlinear interaction between a flexible pipe and the conveyed fluid in the presence of gravity. The stability of the system (fllutter and buckling) depends on parameters such as the dimensionless fluid flow rate, the gravity to bending stiffness ratio and the fluid to pipe mass ratio and it has been studied in detail both numerically and experimentally. It has also been found that the stabilizing or destabilizing effects of fluid flow depends crucially on the direction of gravity respect to the undeformed midline of the pipe. We have also computed the post-critical behavior of the system by solving the full nonlinear equations of the problem and analyzed the transfer of energy within the system in the nonlinear regime. We have formulated the problem in terms of the angles of the midline of the pipe instead of its transverse displacements, so that we can deal with large deflections without recurring to the quasi-linear approximations concerning the pipe curvature usually made in the literature. Supported by the Ministerio de Educación, Cultura y Deportes of Spain under grant DPI 2010-20450 C03-02.

  10. Loop Heat Pipe Startup Behaviors

    NASA Technical Reports Server (NTRS)

    Ku, Jentung

    2016-01-01

    A loop heat pipe must start successfully before it can commence its service. The startup transient represents one of the most complex phenomena in the loop heat pipe operation. This paper discusses various aspects of loop heat pipe startup behaviors. Topics include the four startup scenarios, the initial fluid distribution between the evaporator and reservoir that determines the startup scenario, factors that affect the fluid distribution between the evaporator and reservoir, difficulties encountered during the low power startup, and methods to enhance the startup success. Also addressed are the pressure spike and pressure surge during the startup transient, and repeated cycles of loop startup and shutdown under certain conditions.

  11. Asymmetric Collapse of LOS Pipe.

    DTIC Science & Technology

    1980-05-26

    models that were used to simulate a LOS pipe . Still, the jet was eliminated in a Pinex model with a helical ribbon of polyolefin on the inside surface of...Target from the Pinex Model 71 with Poly Spiral in Experiment LS-3 .41 b l [ SECTION 1 *. INTRODUCTION 1.1 BACKGROUND Line-of-sight (LOS) pipes are...distance. 3.5.7 Simulation of Pinex Pipe . As shown in the photo- graphs provided in Figures 37 and 38, the Pinex-Standard Model and Pinex-Polyolefin Spiral

  12. Variable conductance heat pipe technology

    NASA Technical Reports Server (NTRS)

    Marcus, B. D.; Edwards, D. K.; Anderson, W. T.

    1973-01-01

    Research and development programs in variable conductance heat pipe technology were conducted. The treatment has been comprehensive, involving theoretical and/or experimental studies in hydrostatics, hydrodynamics, heat transfer into and out of the pipe, fluid selection, and materials compatibility, in addition to the principal subject of variable conductance control techniques. Efforts were not limited to analytical work and laboratory experimentation, but extended to the development, fabrication and test of spacecraft hardware, culminating in the successful flight of the Ames Heat Pipe Experiment on the OAO-C spacecraft.

  13. Light pipe - design for efficiency

    SciTech Connect

    Hockey, S.N.

    1985-08-01

    The high cost and availability of materials which are clear enough to transmit light without absorption has limited the idea of piping large-scale quantities of light. The light pipe uses the principle of Total Internal Reflection, with the light guided by very accurate prisms. The transmission of light directed into the end of a Light Pipe at an angle of less than 27.6 degrees is theoretically 100% efficient. The author describes its uses and advantages for lighting offices, cold storage areas, difficult access and hazardous areas, and for solar lighting. Future directions will be to improve the economics and accuracy of the technology. 4 references, 2 figures.

  14. Heat pipe transient response approximation.

    SciTech Connect

    Reid, R. S.

    2001-01-01

    A simple and concise routine that approximates the response of an alkali metal heat pipe to changes in evaporator heat transfer rate is described. This analytically based routine is compared with data from a cylindrical heat pipe with a crescent-annular wick that undergoes gradual (quasi-steady) transitions through the viscous and condenser boundary heat transfer limits. The sonic heat transfer limit can also be incorporated into this routine for heat pipes with more closely coupled condensers. The advantages and obvious limitations of this approach are discussed. For reference, a source code listing for the approximation appears at the end of this paper.

  15. Abrasion protection in process piping

    SciTech Connect

    Accetta, J.

    1996-07-01

    Process piping often is subjected to failure from abrasion or a combination of abrasion and corrosion. Abrasion is a complex phenomenon, with many factors involved to varying degrees. Hard, mineral based alumina ceramic and basalt materials are used to provide protection against abrasion in many piping systems. Successful life extension examples are presented from many different industries. Lined piping components require special attention with regard to operating conditions as well as design and engineering considerations. Economic justification involves direct cost comparisons and avoided costs.

  16. Solar Radio Bursts and Space Weather

    NASA Technical Reports Server (NTRS)

    Gopalswamy, Natchimuthuk,

    2012-01-01

    Radio bursts from the Sun are produced by electron accelerated to relativistic energies by physical processes on the Sun such as solar flares and coronal mass ejections (CMEs). The radio bursts are thus good indicators of solar eruptions. Three types of nonthermal radio bursts are generally associated with CMEs. Type III bursts due to accelerated electrons propagating along open magnetic field lines. The electrons are thought to be accelerated at the reconnection region beneath the erupting CME, although there is another view that the electrons may be accelerated at the CME-driven shock. Type II bursts are due to electrons accelerated at the shock front. Type II bursts are also excellent indicators of solar energetic particle (SEP) events because the same shock is supposed accelerate electrons and ions. There is a hierarchical relationship between the wavelength range of type /I bursts and the CME kinetic energy. Finally, Type IV bursts are due to electrons trapped in moving or stationary structures. The low frequency stationary type IV bursts are observed occasionally in association with very fast CMEs. These bursts originate from flare loops behind the erupting CME and hence indicate tall loops. This paper presents a summary of radio bursts and their relation to CMEs and how they can be useful for space weather predictions.

  17. 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.

  18. Heat pipe life and processing study

    NASA Technical Reports Server (NTRS)

    Antoniuk, D.; Luedke, E. E.

    1979-01-01

    The merit of adding water to the reflux charge in chemically and solvent cleaned aluminum/slab wick/ammonia heat pipes was evaluated. The effect of gas in the performance of three heat pipe thermal control systems was found significant in simple heat pipes, less significant in a modified simple heat pipe model with a short wickless pipe section. Use of gas data for the worst and best heat pipes of the matrix in a variable conductance heat pipe model showed a 3 C increase in the source temperature at full on condition after 20 and 246 years, respectively.

  19. 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.

  20. Multi-terminal pipe routing by Steiner minimal tree and particle swarm optimisation

    NASA Astrophysics Data System (ADS)

    Liu, Qiang; Wang, Chengen

    2012-08-01

    Computer-aided design of pipe routing is of fundamental importance for complex equipments' developments. In this article, non-rectilinear branch pipe routing with multiple terminals that can be formulated as a Euclidean Steiner Minimal Tree with Obstacles (ESMTO) problem is studied in the context of an aeroengine-integrated design engineering. Unlike the traditional methods that connect pipe terminals sequentially, this article presents a new branch pipe routing algorithm based on the Steiner tree theory. The article begins with a new algorithm for solving the ESMTO problem by using particle swarm optimisation (PSO), and then extends the method to the surface cases by using geodesics to meet the requirements of routing non-rectilinear pipes on the surfaces of aeroengines. Subsequently, the adaptive region strategy and the basic visibility graph method are adopted to increase the computation efficiency. Numeral computations show that the proposed routing algorithm can find satisfactory routing layouts while running in polynomial time.

  1. On the theory of type I X-ray bursts - The energetics of bursts and the nuclear fuel reservoir in the envelope

    NASA Technical Reports Server (NTRS)

    Fujimoto, Masayuki Y.; Sztajno, Mirek; Lewin, Walter H. G.; Van Paradijs, Jan

    1987-01-01

    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.

  2. B Plant process piping replacement feasibility study

    SciTech Connect

    Howden, G.F.

    1996-02-07

    Reports on the feasibility of replacing existing embedded process piping with new more corrosion resistant piping between cells and between cells and a hot pipe trench of a Hanford Site style canyon facility. Provides concepts for replacement piping installation, and use of robotics to replace the use of the canyon crane as the primary means of performing/supporting facility modifications (eg, cell lining, pipe replacement, equipment reinstallation) and operational maintenenace.

  3. Fiberglass Reinforced Piping for Shipboard Systems

    DTIC Science & Technology

    1976-07-01

    B16.5 far flanges. Piping is gal- vanized. Thickness corresponds to standard weight. Diameters are 8" and 10”. Joininq. The piping system is welded ...critical, standard elbows are used in place of bends. Supports. Pipe hangers are made of U-bolts through angle iron supports welded directly to the ship...and 30" . Joining. The piping system is welded wherever possible, including at bulkhead penetrations. Spuds are welded into the pipe to form tee

  4. Intermediate Temperature Water Heat Pipe Tests

    NASA Technical Reports Server (NTRS)

    Devarakonda, Angirasa; Xiong, Da-Xi; Beach, Duane E.

    2005-01-01

    Heat pipes are among the most promising technologies for space radiator systems. Water heat pipes are explored in the intermediate temperature range of 400 to above 500 K. The thermodynamic and thermo-physical properties of water are reviewed in this temperature range. Test data are reported for a copper-water heat pipe. The heat pipe was tested under different orientations. Water heat pipes show promise in this temperature range. Fabrication and testing issues are being addressed.

  5. Intermediate Temperature Water Heat Pipe Tests

    NASA Technical Reports Server (NTRS)

    Devarakonda, Angirasa; Xiong, Daxi; Beach, Duane E.

    2004-01-01

    Heat pipes are among the most promising technologies for space radiator systems. Water heat pipes are explored in the intermediate temperature range of 400 to above 500 K. The thermodynamic and thermo-physical properties of water are reviewed in this temperature range. Test Data are reported for a copper-water heat pipe. The heat pipe was tested under different orientations. Water heat pipes show promise in this temperature range.Fabrication and testing issues are being addressed.

  6. Method for casting polyethylene pipe

    NASA Technical Reports Server (NTRS)

    Elam, R. M., Jr.

    1973-01-01

    Short lengths of 7-cm ID polyethylene pipe are cast in a mold which has a core made of room-temperature-vulcanizable (RTV) silicone. Core expands during casting and shrinks on cooling to allow for contraction of the polyethylene.

  7. Corrugated pipe adhesive applicator apparatus

    DOEpatents

    Shirey, R.A.

    1983-06-14

    Apparatus for coating selected portions of the troughs of a corrugated pipe with an adhesive includes a support disposed within the pipe with a reservoir containing the adhesive disposed on the support. A pump, including a spout, is utilized for supplying the adhesive from the reservoir to a trough of the pipe. A rotatable applicator is supported on the support and contacts the trough of the pipe. The applicator itself is sized so as to fit within the trough, and contacts the adhesive in the trough and spreads the adhesive in the trough upon rotation. A trough shield, supported by the support and disposed in the path of rotation of the applicator, is utilized to prevent the applicator from contacting selected portions of the trough. A locator head is also disposed on the support and provides a way for aligning the spout, the applicator, and the trough shield with the trough. 4 figs.

  8. Loop Heat Pipe Startup Behaviors

    NASA Technical Reports Server (NTRS)

    Ku, Jentung

    2014-01-01

    A loop heat pipe must start successfully before it can commence its service. The start-up transient represents one of the most complex phenomena in the loop heat pipe operation. This paper discusses various aspects of loop heat pipe start-up behaviors. Topics include the four start-up scenarios, the initial fluid distribution between the evaporator and reservoir that determines the start-up scenario, factors that affect the fluid distribution between the evaporator and reservoir, difficulties encountered during the low power start-up, and methods to enhance the start-up success. Also addressed are the thermodynamic constraint between the evaporator and reservoir in the loop heat pipe operation, the superheat requirement for nucleate boiling, pressure spike and pressure surge during the start-up transient, and repeated cycles of loop start-up andshutdown under certain conditions.

  9. Heat pipe radiators for space

    NASA Technical Reports Server (NTRS)

    Sellers, J. P.

    1976-01-01

    Analysis of the data heat pipe radiator systems tested in both vacuum and ambient environments was continued. The systems included (1) a feasibility VCHP header heat-pipe panel, (2) the same panel reworked to eliminate the VCHP feature and referred to as the feasibility fluid header panel, and (3) an optimized flight-weight fluid header panel termed the 'prototype.' A description of freeze-thaw thermal vacuum tests conducted on the feasibility VCHP was included. In addition, the results of ambient tests made on the feasibility fluid header are presented, including a comparison with analytical results. A thermal model of a fluid header heat pipe radiator was constructed and a computer program written. The program was used to make a comparison of the VCHP and fluid-header concepts for both single and multiple panel applications. The computer program was also employed for a parametric study, including optimum feeder heat pipe spacing, of the prototype fluid header.

  10. Corrugated pipe adhesive applicator apparatus

    DOEpatents

    Shirey, Ray A.

    1983-06-14

    Apparatus for coating selected portions of the troughs of a corrugated pipe within an adhesive includes a support disposed within the pipe with a reservoir containing the adhesive disposed on the support. A pump, including a spout, is utilized for supplying the adhesive from the reservoir to a trough of the pipe. A rotatable applicator is supported on the support and contacts the trough of the pipe. The applicator itself is sized so as to fit within the trough, and contacts the adhesive in the trough and spreads the adhesive in the trough upon rotation. A trough shield, supported by the support and disposed in the path of rotation of the applicator, is utilized to prevent the applicator from contacting selected portions of the trough. A locator head is also disposed on the support and provides a way for aligning the spout, the applicator, and the trough shield with the trough.

  11. Physics of heat pipe rewetting

    NASA Technical Reports Server (NTRS)

    Chan, S. H.

    1994-01-01

    This is the final report which summarizes the research accomplishments under the project entitled 'Physics of Heat Pipe Rewetting' under NASA Grant No. NAG 9-525, Basic, during the period of April 1, 1991 to January 31, 1994. The objective of the research project was to investigate both analytically and experimentally the rewetting characteristics of the heated, grooved plate. The grooved plate is to simulate the inner surface of the vapor channel in monogroove heat pipes for space station design. In such designs, the inner surface of the vapor channel is threaded with monogrooves. When the heat pipe is thermally overloaded, dryout of the monogroove surface occurs. Such a dryout surface should be promptly rewetted to prevent the failure of the heat pipe operation in the thermal radiator of the space station.

  12. 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

  13. Effects of Stormwater Pipe Size and Rainfall on Sediment and Nutrients Delivered to a Coastal Bayou.

    PubMed

    Grigas, Daniel; Lehrter, John; Cebrian, Just; Chen, Yushun; Ehmen, Brenna; Woodrey, Mark

    2015-09-01

    Pollutants discharged from stormwater pipes can cause water quality and ecosystem problems in coastal bayous. A study was conducted to characterize sediment and nutrients discharged by small and large (< 20 cm and >20 cm in internal diameters, respectively) pipes under different rainfall intensities (< 2.54 cm and > 2.54 cm, respectively). Results showed that large pipes had greater discharge than small pipes. Pollutants concentrations did not vary by pipe size. Large pipes had greater loads of TSS (138.2 vs. 24.0 mg/s), NO3(-) (5.54 vs. 2.74 mg/s), and NH4(+) (0.39 vs. 0.19 mg/s) than small pipes. Neither discharge nor constituents varied by rainfall events. Pipe size may be a useful metric for estimating loads to a system. Nutrient reduction efforts should be directed to reducing the dissolved nutrient pools, while stormwater management efforts should be directed to reducing pipe freshwater discharge volumes that drive constituent loads.

  14. The dynamics of axisymmetric swirling flows in a diverging or contracting circular pipe

    NASA Astrophysics Data System (ADS)

    Rusak, Zvi; Wang, Shixiao

    2009-11-01

    This paper describes a study of the effect of pipe divergence and contraction on the stability and breakdown of axisymmetric swirling flows in a long, finite-length, circular pipe. The work extends the theory of Wang & Rusak (1997). The approach is based on a rigorous analysis of the axisymmetric, steady and inviscid flow equations with non-periodic boundary conditions. The analysis firmly establishes the global bifurcation of flow states in the pipe (solutions of the Squire-Long PDE) by relating it to the bifurcation of solutions of the columnar flow problem (solutions of the resulting ODE) and using a new flow force relationship between the inlet and outlet states. This technique provides a simple, yet exact, method of analyzing the complex flow behavior including transitions from near-columnar vortex states to flow fields with large separation (stagnation) zones along the pipe centerline (breakdown states) or along the pipe wall (swirl induced wall separation). Bifurcation diagrams for base vortex models including the solid- body rotation and the Burgers vortex are presented. The stability characteristics of the various branches of solutions and the flow dynamics in the pipe under various perturbations are discussed. Results show that pipe divergence or contraction significantly modify the global flow behavior in a straight pipe and shed light on the effect of pipe geometry on the mechanism of vortex breakdown.

  15. Heat Pipe Thermal Conditioning Panel

    NASA Technical Reports Server (NTRS)

    Saaski, E. W.

    1973-01-01

    The technology involved in designing and fabricating a heat pipe thermal conditioning panel to satisfy a broad range of thermal control system requirements on NASA spacecraft is discussed. The design specifications were developed for a 30 by 30 inch heat pipe panel. The fundamental constraint was a maximum of 15 gradient from source to sink at 300 watts input and a flux density of 2 watts per square inch. The results of the performance tests conducted on the panel are analyzed.

  16. Mapping Temperatures On Heat Pipes

    NASA Technical Reports Server (NTRS)

    Gunnerson, Fred S.; Thorncroft, Glen E.

    1993-01-01

    Paints containing thermochromic liquid crystals (TLC's) used to map temperatures on heat pipes and thermosyphons. Color of thermally sensitive TLC coat changes reversibly upon heating or cooling. Each distinct color indicates particular temperature. Transient and steady-state isotherms become visible as colored bands. Positions and movements of bands yield information about startup transients, steady-state operation, cooler regions containing noncondensible gas, and other phenomena relevant to performance of heat pipe.

  17. Piping Inelastic Fracture Mechanics Analysis.

    DTIC Science & Technology

    1980-06-30

    DOCUMENTATION PAGE BEFORE COMPLETING FORM I. REPORT NUMBER 12. GOVT ACCESSION NO. S. RECIPIENT’S CATALOG NUMBER NUREG /CR 1119 4259 NRL Memorandum Report _4259...Steel Piping of Boiling Water Reactor Plants," US Nuclear Regulatory Commission, NUREG -75/067, October, 1975. 2. "Investigation and Evaluation of...Stress-Corrosion Cracking in Piping of Light-Water Reactor Plants," US Nuclear Regulatory Commission, NUREG -0531, February, 1979. 3. F.J. Witt, W.H

  18. Pipe weld crown removal device

    DOEpatents

    Sword, Charles K.; Sette, Primo J.

    1992-01-01

    A device is provided for grinding down the crown of a pipe weld joining aligned pipe sections so that the weld is substantially flush with the pipe sections joined by the weld. The device includes a cage assembly comprising a pair of spaced cage rings adapted to be mounted for rotation on the respective pipe sections on opposite sides of the weld, a plurality of grinding wheels, supported by the cage assembly for grinding down the crown of the weld, and a plurality of support shafts, each extending longitudinally along the joined pipe sections, parallel thereto, for individually mounting respective grinding wheels. Each end of the support shafts is mounted for rotation in a bearing assembly housed within a radially directed opening in a corresponding one of the cage rings so as to provide radial movement of the associated shaft, and thus of the associated grinding wheel, towards and away from the weld. A first drive sprocket provides rotation of the cage assembly around the pipe sections while a second drive unit, driven by a common motor, provides rotation of the grinding wheels.

  19. Pipe weld crown removal device

    SciTech Connect

    Sword, C.K.; Sette, P.J.

    1992-11-24

    A device is provided for grinding down the crown of a pipe weld joining aligned pipe sections so that the weld is substantially flush with the pipe sections joined by the weld. The device includes a cage assembly comprising a pair of spaced cage rings adapted to be mounted for rotation on the respective pipe sections on opposite sides of the weld, a plurality of grinding wheels, supported by the cage assembly for grinding down the crown of the weld, and a plurality of support shafts, each extending longitudinally along the joined pipe sections, parallel thereto, for individually mounting respective grinding wheels. Each end of the support shafts is mounted for rotation in a bearing assembly housed within a radially directed opening in a corresponding one of the cage rings so as to provide radial movement of the associated shaft, and thus of the associated grinding wheel, towards and away from the weld. A first drive sprocket provides rotation of the cage assembly around the pipe sections while a second drive unit, driven by a common motor, provides rotation of the grinding wheels. 2 figs.

  20. Pipe weld crown removal device

    SciTech Connect

    Sword, C.K.; Sette, P.J.

    1991-12-31

    This invention is comprised of a device that provides for grinding down the crown of a pipe weld joining aligned pipe sections so that the weld is substantially flush with the pipe sections joined by the weld. The device includes a cage assembly comprising a pair of spaced cage rings adapted to be mounted for rotation on the respective pipe sections on opposite sides of the weld, a plurality of grinding wheels, supported by the cage assembly for grinding down the crown of the weld, and a plurality of support shafts, each extending longitudinally along the joined pipe sections, parallel thereto, for individually mounting respective grinding wheels. Each end of the support shafts is mounted for rotation in a bearing assembly housed within a radially directed opening in a corresponding one of the cage rings so as to provide radial movement of the associated shaft, and thus of the associated grinding wheel, towards and away from the weld. A first drive sprocket provides rotation of the cage assembly around the pipe sections while a second drive unit, driven by a common motor, provides rotation of the grinding wheels.

  1. Heat pipe turbine vane cooling

    SciTech Connect

    Langston, L.; Faghri, A.

    1995-10-01

    The applicability of using heat pipe principles to cool gas turbine vanes is addressed in this beginning program. This innovative concept involves fitting out the vane interior as a heat pipe and extending the vane into an adjacent heat sink, thus transferring the vane incident heat transfer through the heat pipe to heat sink. This design provides an extremely high heat transfer rate and an uniform temperature along the vane due to the internal change of phase of the heat pipe working fluid. Furthermore, this technology can also eliminate hot spots at the vane leading and trailing edges and increase the vane life by preventing thermal fatigue cracking. There is also the possibility of requiring no bleed air from the compressor, and therefore eliminating engine performance losses resulting from the diversion of compressor discharge air. Significant improvement in gas turbine performance can be achieved by using heat pipe technology in place of conventional air cooled vanes. A detailed numerical analysis of a heat pipe vane will be made and an experimental model will be designed in the first year of this new program.

  2. Heat pipe turbine vane cooling

    SciTech Connect

    Langston, L.; Faghri, A.

    1995-12-31

    The applicability of using heat pipe principles to cool gas turbine vanes is addressed in this beginning program. This innovative concept involves fitting out the vane interior as a heat pipe and extending the vane into an adjacent heat sink, thus transferring the vane incident heat transfer through the heat pipe to heat sink. This design provides an extremely high heat transfer rate and a uniform temperature along the vane due to the internal change of phase of the heat pipe working fluid. Furthermore, this technology can also eliminate hot spots at the vane leading and trailing edges and increase the vane life by preventing thermal fatigue cracking. There is also the possibility of requiring no bleed air from the compressor, and therefore eliminating engine performance losses resulting from the diversion of compressor discharge air. Significant improvement in gas turbine performance can be achieved by using heat pipe technology in place of conventional air cooled vanes. A detailed numerical analysis of a heat pipe vane will be made and an experimental model will be designed in the first year of this new program.

  3. Automated internal pipe cutting device

    DOEpatents

    Godlewski, William J.; Haffke, Gary S.; Purvis, Dale; Bashar, Ronald W.; Jones, Stewart D.; Moretti, Jr., Henry; Pimentel, James

    2003-01-21

    The invention is a remotely controlled internal pipe cutting device primarily used for cutting pipes where the outside of the pipe is inaccessible at the line where the cut is to be made. The device includes an axial ram within a rotational cylinder which is enclosed in a housing. The housing is adapted for attachment to an open end of the pipe and for supporting the ram and cylinder in cantilever fashion within the pipe. A radially movable cutter, preferably a plasma arc torch, is attached to the distal end of the ram. A drive mechanism, containing motors and mechanical hardware for operating the ram and cylinder, is attached to the proximal end of the housing. The ram and cylinder provide for moving the cutter axially and circumferentially, and a cable assembly attached to a remote motor provide for the movement of the cutter radially, within the pipe. The control system can be adjusted and operated remotely to control the position and movement of the cutter to obtain the desired cut. The control system can also provide automatic standoff control for a plasma arc torch.

  4. Heat pipe cooled power magnetics

    NASA Technical Reports Server (NTRS)

    Chester, M. S.

    1979-01-01

    A high frequency, high power, low specific weight (0.57 kg/kW) transformer developed for space use was redesigned with heat pipe cooling allowing both a reduction in weight and a lower internal temperature rise. The specific weight of the heat pipe cooled transformer was reduced to 0.4 kg/kW and the highest winding temperature rise was reduced from 40 C to 20 C in spite of 10 watts additional loss. The design loss/weight tradeoff was 18 W/kg. Additionally, allowing the same 40 C winding temperature rise as in the original design, the KVA rating is increased to 4.2 KVA, demonstrating a specific weight of 0.28 kg/kW with the internal loss increased by 50W. This space environment tested heat pipe cooled design performed as well electrically as the original conventional design, thus demonstrating the advantages of heat pipes integrated into a high power, high voltage magnetic. Another heat pipe cooled magnetic, a 3.7 kW, 20A input filter inductor was designed, developed, built, tested, and described. The heat pipe cooled magnetics are designed to be Earth operated in any orientation.

  5. Agricultural drainage pipe detection using ground penetrating radar: Effects of antenna orientation relative to drainage pipe directional trend

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Locating buried agricultural drainage pipes is a difficult problem confronting farmers and land improvement contractors, especially in the Midwest U.S., where the removal of excess soil water using subsurface drainage systems is a common farm practice. Enhancing the efficiency of soil water removal ...

  6. Meteoroid Protection Methods for Spacecraft Radiators Using Heat Pipes

    NASA Technical Reports Server (NTRS)

    Ernst, D. M.

    1979-01-01

    Various aspects of achieving a low mass heat pipe radiator for the nuclear electric propulsion spacecraft were studied. Specific emphasis was placed on a concept applicable to a closed Brayton cycle power sub-system. Three aspects of inter-related problems were examined: (1) the armor for meteoroid protection, (2) emissivity of the radiator surface, and (3) the heat pipe itself. The study revealed several alternatives for the achievement of the stated goal, but a final recommendation for the best design requires further investigation.

  7. Effects of pipe diameters on the pressures during delayed load rejection in high-head pumped storage power stations

    NASA Astrophysics Data System (ADS)

    Zeng, W.; Yang, J. D.

    2014-03-01

    High-head pumped storage power stations face serious problems related to the transient process, especially in the area of delayed load rejection in stations with annular piping layouts. The controlled pressures are adversely affected, which leads to many problems in the engineering design phase. In this study, we investigated this condition through theoretical analysis, numerical simulation, and actual engineering practice. We concluded that the root cause of the pressure issues is the flow switching resulted from the non-synchronous changes in pressure between each branch pipe. Moreover, we examined the impact of the diameters of the upstream main pipe and branch pipe on the controlled pressures and determined that the diameter of the branch pipe has a major influence on the pressures as it changes the flow switching rate. A similar investigation was conducted for downstream pipes. Our conclusions can be applied to actual engineering practice for high-head pumped storage power stations.

  8. Piping inspection round robin

    SciTech Connect

    Heasler, P.G.; Doctor, S.R.

    1996-04-01

    The piping inspection round robin was conducted in 1981 at the Pacific Northwest National Laboratory (PNNL) to quantify the capability of ultrasonics for inservice inspection and to address some aspects of reliability for this type of nondestructive evaluation (NDE). The round robin measured the crack detection capabilities of seven field inspection teams who employed procedures that met or exceeded the 1977 edition through the 1978 addenda of the American Society of Mechanical Engineers (ASME) Section 11 Code requirements. Three different types of materials were employed in the study (cast stainless steel, clad ferritic, and wrought stainless steel), and two different types of flaws were implanted into the specimens (intergranular stress corrosion cracks (IGSCCs) and thermal fatigue cracks (TFCs)). When considering near-side inspection, far-side inspection, and false call rate, the overall performance was found to be best in clad ferritic, less effective in wrought stainless steel and the worst in cast stainless steel. Depth sizing performance showed little correlation with the true crack depths.

  9. Ultrasonic isolation of buried pipes

    NASA Astrophysics Data System (ADS)

    Leinov, Eli; Lowe, Michael J. S.; Cawley, Peter

    2016-02-01

    Long-range guided wave testing (GWT) is used routinely for the monitoring and detection of corrosion defects in above ground pipelines. The GWT test range in buried, coated pipelines is greatly reduced compared to above ground configurations due to energy leakage into the embedding soil. In this paper, the effect of pipe coatings on the guided wave attenuation is investigated with the aim of increasing test ranges for buried pipelines. The attenuation of the T(0,1) and L(0,2) guided wave modes is measured using a full-scale experimental apparatus in a fusion-bonded epoxy (FBE)-coated 8 in. pipe, buried in loose and compacted sand. Tests are performed over a frequency range typically used in GWT of 10-35 kHz and compared with model predictions. It is shown that the application of a low impedance coating between the FBE layer and the sand effectively decouples the influence of the sand on the ultrasound leakage from the buried pipe. Ultrasonic isolation of a buried pipe is demonstrated by coating the pipe with a Polyethylene (PE)-foam layer that has a smaller impedance than both the pipe and sand, and has the ability to withstand the overburden load from the sand. The measured attenuation in the buried PE-foam-FBE-coated pipe is found to be substantially reduced, in the range of 0.3-1.2 dB m-1 for loose and compacted sand conditions, compared to measured attenuation of 1.7-4.7 dB m-1 in the buried FBE-coated pipe without the PE-foam. The acoustic properties of the PE-foam are measured independently using ultrasonic interferometry and incorporated into model predictions of guided wave propagation in buried coated pipe. Good agreement is found between the experimental measurements and model predictions. The attenuation exhibits periodic peaks in the frequency domain corresponding to the through-thickness resonance frequencies of the coating layer. The large reduction in guided wave attenuation for PE-coated pipes would lead to greatly increased GWT test ranges; such

  10. NEP heat pipe radiators. [Nuclear Electric Propulsion

    NASA Technical Reports Server (NTRS)

    Ernst, D. M.

    1979-01-01

    This paper covers improvements of heat pipe radiators for the thermionic NEP design. Liquid metal heat pipes are suitable as spacecraft radiator elements because of high thermal conductance, low mass and reliability, but the NEP thermionic system design was too large and difficult to fabricate. The current integral collector-radiator design consisting of several layers of thermionic converters, the annular-tangential collector heat pipe, the radiator heat pipe, and the transition zone designed to minimize the temperature difference between the collector heat pipe and radiator heat pipe are described. Finally, the design of micrometeoroid armor protection and the fabrication of the stainless steel annular heat pipe with a tangential arm are discussed, and it is concluded that the heat rejection system for the thermionic NEP system is well advanced, but the collector-radiator heat pipe transition and the 8 to 10 m radiator heat pipe with two bends require evaluation.

  11. Size safety valve discharge piping with a programmable calculator

    SciTech Connect

    D'ambra, A.

    1982-10-01

    Discussed is a program that will aid in the proper sizing of steam safety valve discharge piping frequently encountered in steam distribution systems. Basis for calculation is the ASME/ANSI Power Piping Code. Code reference is not necessary for running the program. Presented is a safety valve installation schematic, the program listing, data registers, constants, and a sample problem. The calculation done by this program is a fluid momentum check to assure that selected pipe sizes yield velocities and back pressures such that the steam blowing out of the safety valve is driven up the stack and not backwards out of the clearance. Back pressure should not exceed safety valve manufacturers' limits to realize full design capacity of the installation.

  12. Application of burst vibrothermography to characterize planar vertical cracks

    NASA Astrophysics Data System (ADS)

    Mendioroz, Arantza; Celorrio, Ricardo; Cifuentes, Ángel; Zatón, Lander; Salazar, Agustín.

    2016-05-01

    We present a method to characterize vertical cracks in a fast way using burst vibrothermography. In this technique the sample is excited by ultrasounds and, at the defect, rubbing of the contacting surfaces produces heat that can be detected as a temperature rise at the surface using an infrared camera. In this work, first we present the solution of the direct problem, i.e., the calculation of the surface temperature distribution produced by a vertical heat source representing a crack excited by an ultrasound burst, and we choose the information that will be used to characterize the crack, namely, one thermogram and one timing-graph. Next we address the inverse problem, consisting of finding the heat source distribution that is responsible for the observed surface temperature. This inverse problem is ill-posed, and a naïve inversion process is unstable. We propose to use three penalty terms, based on zero order Tikhonov and Total Variation functionals and the Lasso method, to stabilize the inversion. By inverting synthetic data, we analyze the performance of the algorithm as a function of the depth of the heat source and we study the effect of the burst duration and noise level in the data on the quality of the reconstructions. Finally, we invert experimental data taken in samples containing calibrated heat sources. The results show that it is possible to characterize vertical cracks down to depths of 6 mm in AISI 304 stainless steel.

  13. Transient Simulation of Accumulating Particle Deposition in Pipe Flow

    NASA Astrophysics Data System (ADS)

    Hewett, James; Sellier, Mathieu

    2015-11-01

    Colloidal particles that deposit in pipe systems can lead to fouling which is an expensive problem in both the geothermal and oil & gas industries. We investigate the gradual accumulation of deposited colloids in pipe flow using numerical simulations. An Euler-Lagrangian approach is employed for modelling the fluid and particle phases. Particle transport to the pipe wall is modelled with Brownian motion and turbulent diffusion. A two-way coupling exists between the fouled material and the pipe flow; the local mass flux of depositing particles is affected by the surrounding fluid in the near-wall region. This coupling is modelled by changing the cells from fluid to solid as the deposited particles exceed each local cell volume. A similar method has been used to model fouling in engine exhaust systems (Paz et al., Heat Transfer Eng., 34(8-9):674-682, 2013). We compare our deposition velocities and deposition profiles with an experiment on silica scaling in turbulent pipe flow (Kokhanenko et al., 19th AFMC, 2014).

  14. Stirling Colgate and Gamma-Ray Bursts

    NASA Astrophysics Data System (ADS)

    Lamb, Donald

    2014-10-01

    Even before the discovery of gamma-ray bursts (GRBs), Stirling Colgate proposed that bursts of x rays and gamma rays might be produced by a relativistic shock created in the supernova explosion of a massive star. We trace the scientific story of GRBs from their detection to the present, highlighting along the way Stirling's interest in them and his efforts to understand them. We summarize our current understanding that short, soft, repeating bursts are produced by magnetic neutron stars; short, hard bursts are produced by the mergers of neutron star-neutron star binaries; and long, hard bursts are produced by the core collapse of massive stars that have lost their hydrogen and helium envelopes. We then discuss some important open questions about GRBs and how they might be answered. We conclude by describing the recent serendipitous discovery of an x-ray burst of exactly the kind he proposed, and the insights into core collapse supernovae and GRBs that it provided.

  15. Hardness/intensity correlations among BATSE bursts

    NASA Technical Reports Server (NTRS)

    Paciesas, William S.; Pendleton, Geoffrey N.; Kouveliotou, Chryssa; Fishman, Gerald J.; Meegan, Charles A.; Wilson, Robert B.

    1992-01-01

    Conclusions about the nature of gamma-ray bursts derived from the size-frequency distribution may be altered if a significant correlation exists between burst intensity and spectral shape. Moreover, if gamma-ray bursts have a cosmological origin, such a correlation may be expected to result from the expansion of the universe. We have performed a rudimentary search of the BATSE bursts for hardness/intensity correlations. The range of spectral shapes was determined for each burst by computing the ratio of the intensity in the range 100-300 keV to that in 55-300 keV. We find weak evidence for the existence of a correlation, the strongest effect being present when comparing the maximum hardness ratio for each burst with its maximum rate.

  16. Burst interference in TDMA radio systems

    NASA Astrophysics Data System (ADS)

    Lei, Z.; Chen, M.-X.; Feher, K.

    Analytical and experimental studies show that burst interference in TDMA systems causes spectral spreading, which depends on the gating rate and duty cycle of the burst. A probability-of-error performance study of IJF (intersymbol and jitter-free) OQPSK systems in the presence of burst interference signals shows that the higher gating rate or smaller duty cycle of the burst will introduce more degradation because of increased spectral spreading. It is concluded that the transmitted power of the burst signal should be limited more strictly than that of CW signals, because the burst interference causes more degradation in the performance of the desired channel than nonburst interference with the same (C/I)mean.

  17. Transitions to Synchrony in Coupled Bursting Neurons

    NASA Astrophysics Data System (ADS)

    Dhamala, Mukeshwar; Jirsa, Viktor K.; Ding, Mingzhou

    2004-01-01

    Certain cells in the brain, for example, thalamic neurons during sleep, show spike-burst activity. We study such spike-burst neural activity and the transitions to a synchronized state using a model of coupled bursting neurons. In an electrically coupled network, we show that the increase of coupling strength increases incoherence first and then induces two different transitions to synchronized states, one associated with bursts and the other with spikes. These sequential transitions to synchronized states are determined by the zero crossings of the maximum transverse Lyapunov exponents. These results suggest that synchronization of spike-burst activity is a multi-time-scale phenomenon and burst synchrony is a precursor to spike synchrony.

  18. Partnership in Innovative Preparation for Educators and Students (PIPES)

    DTIC Science & Technology

    2013-12-23

    purifications process . And her music pen is still working. She really enjoys it. She is so proud of it.  “He absolutely loved it!!! The hands-on experience is... artistic , and innovative students to solve our future problems related to science, technology, engineering, and mathematics (STEM). PIPES research...aspired to attract and encourage a new generation of creative, artistic , and innovative students to solve our future problems related to science

  19. Spectral features of solar gradual microwave bursts.

    NASA Astrophysics Data System (ADS)

    Yao, J.-X.

    The author presents data and spectral analysis of five solar gradual microwave bursts (GMB's), which are associated with the gradual hard X-ray bursts (GHB's). The durations of GMB's are about tens of minutes and are longer than that of impulsive bursts (5 min.) and the sources of GMB's are high in the corona. Therefore, one may attribute the long durations and spectral index decrease to the high radio sources.

  20. Ceramic Matrix Composite Vane Subelement Burst Testing

    NASA Technical Reports Server (NTRS)

    Brewer, David N.; Verrilli, Michael; Calomino, Anthony

    2006-01-01

    Burst tests were performed on Ceramic Matrix Composite (CMC) vane specimens, manufactured by two vendors, under the Ultra Efficient Engine Technology (UEET) project. Burst specimens were machined from the ends of 76mm long vane sub-elements blanks and from High Pressure Burner Rig (HPBR) tested specimens. The results of burst tests will be used to compare virgin specimens with specimens that have had an Environmental Barrier Coating (EBC) applied, both HPBR tested and untested, as well as a comparison between vendors.

  1. A Gamma-Ray Burst Trigger Toolkit

    NASA Technical Reports Server (NTRS)

    Band, David L.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    The detection rate of a gamma-ray burst detector can be increased by using a count rate trigger with many accumulation times DELTAt and energy bands DELTAE Because a burst's peak flux varies when averaged over different DELTAt and DELTAE the nominal sensitivity (the numerical value of the peak flux) of a trigger system is less important than how much fainter a burst could be at the detection threshold as DELTAt and DELTAE are changed. The relative sensitivity of different triggers can be quantified by referencing the detection threshold back to the peak flux for a fiducial value of DELTAt and DELTA E. This mapping between peak flux values for different sets of DELTAt and DELTAE varies from burst to burst. Quantitative estimates of the burst detection rate for a given detector and trigger system can be based on the observed rate at a measured peak flux value in this fiducial trigger. Predictions of a proposed trigger's burst detection rate depend on the assumed burst population, and these predictions can be wildly in error for triggers that differ significantly from previous missions. I base the fiducial rate on the BATSE observations: 550 bursts per sky above a peak flux of 0.3 ph per square centimeter per second averaged over DELTAt=1.024 sec and DELTAE=50-300 keV. Using a sample of 100 burst lightcurves I find that triggering on any value of DELTAt that is a multiple of 0.064 sec decreases the average threshold peak flux on the 1.024 sec timescale by a factor of 0.6. Extending DELTAE to lower energies includes the large flux of the X-ray background, increasing the background count rate. Consequently a low energy DELTAE is advantageous only for very soft bursts. Whether a large fraction of the population of bright bursts is soft is disputed; the new population of X-ray Flashes is soft but relatively faint.

  2. Ballerina - pirouettes in search of gamma bursts

    NASA Astrophysics Data System (ADS)

    Brandt, S.; Lund, N.; Pedersen, H.; Hjorth, J.; BALLERINA Collaboration

    1999-09-01

    The cosmological origin of gamma ray bursts has now been established with reasonable certainty. Many more bursts will need to be studied to establish the typical distance scale, and to map out the large diversity in properties which have been indicated by the first handful of events. We are proposing Ballerina, a small satellite to provide accurate positions and new data on the gamma-ray bursts. We anticipate a detection rate an order of magnitude larger than obtained from Beppo-SAX.

  3. Magnetic refrigeration apparatus with heat pipes

    DOEpatents

    Barclay, John A.; Prenger, Jr., F. Coyne

    1987-01-01

    A magnetic refrigerator operating in the 4 to 20 K range utilizes heat pipes to transfer heat to and from the magnetic material at the appropriate points during the material's movement. In one embodiment circular disks of magnetic material can be interleaved with the ends of the heat pipes. In another embodiment a mass of magnetic material reciprocatingly moves between the end of the heat pipe of pipes that transmits heat from the object of cooling to the magnetic material and the end of the heat pipe or pipes that transmits heat from the magnetic material to a heat sink.

  4. Magnetic refrigeration apparatus with heat pipes

    DOEpatents

    Barclay, J.A.; Prenger, F.C. Jr.

    1985-10-25

    A magnetic refrigerator operating in the 4 to 20 K range utilizes heat pipes to transfer heat to and from the magnetic material at the appropriate points during the material's movement. In one embodiment circular disks of magnetic material can be interleaved with the ends of the heat pipes. In another embodiment a mass of magnetic material reciprocatingly moves between the end of the heat pipe or pipes that transmits heat from the object of cooling to the magnetic material and the end of the heat pipe or pipes that transmits heat from the magnetic material to a heat sink.

  5. Turbine-Driven Pipe-Cleaning Brush

    NASA Technical Reports Server (NTRS)

    Werlink, Rudy J.; Rowell, David E.

    1994-01-01

    Simple pipe-cleaning device includes small turbine wheel axially connected, by standoff, to circular brush. Turbine wheel turns on hub bearing attached to end of upstream cable. Turbine-and-brush assembly inserted in pipe with cable trailing upstream and brush facing downstream. Water or cleaning solution pumped through pipe. Cable held at upstream end, so it holds turbine and brush in pipe at location to be cleaned. Flow in pipe turns turbine, which turns wheel, producing desired cleaning action. In addition to brushing action, device provides even mixing of cleaning solution in pipe.

  6. Helium bubble bursting in tungsten

    SciTech Connect

    Sefta, Faiza; Juslin, Niklas; Wirth, Brian D.

    2013-12-28

    Molecular dynamics simulations have been used to systematically study the pressure evolution and bursting behavior of sub-surface helium bubbles and the resulting tungsten surface morphology. This study specifically investigates how bubble shape and size, temperature, tungsten surface orientation, and ligament thickness above the bubble influence bubble stability and surface evolution. The tungsten surface is roughened by a combination of adatom “islands,” craters, and pinholes. The present study provides insight into the mechanisms and conditions leading to various tungsten topology changes, which we believe are the initial stages of surface evolution leading to the formation of nanoscale fuzz.

  7. Bursts in inclined layer convection

    NASA Astrophysics Data System (ADS)

    Busse, F. H.; Clever, R. M.

    2000-08-01

    A new instability of longitudinal rolls in an inclined fluid layer heated from below is analyzed in the case of the Prandtl number P=0.71. The instability assumes the form of subharmonic undulations and evolves into a spatially chaotic pattern when the angle of inclination is of the order of 20°. The chaotic state rapidly decays and longitudinal rolls recover until the next burst of chaotic convection occurs. The theoretical findings closely correspond to recent experimental observations by Daniels et al. [Phys. Rev. Lett. (to be published)].

  8. Volatile pipe prices ahead

    SciTech Connect

    Perkins, C.

    1988-01-01

    Over the last 10 years, prices for oilfield casing and tubing have shot up and down like a roller coaster. Average pipe prices went up 80 percent in the 1979-81 drilling boom. They dropped 50 percent in the 1982-83 period, only to recover 20 percent in 1984-85. The collapse of crude prices caused another 30 percent drop in 1986. Since they bottomed out in August of that year, prices have come up by 60 percent. The key question: ''What lies ahead.'' The short answer: ''Probably more of the same''. This article looks at what has caused price fluctuations of such magnitude and volatility over the past several years to assess the outlook for 1988 and beyond. The author says we are not on the brink of a severe OCTG shortage of any sort, though there may be some very localized spot shortages in terms of deliverability and price. There is likely to be some build up of tubular inventory among supply houses wary of losing regular customers to those with adequate inventories. The characteristic first-of-the-year dip in the active rig count will supplement a slight inventory building, as will an expected increase in imports. The bottomline impact for the wellsite is there is little chance for substantial price increases until the third or fourth quarter of this year. Even then, a considerable jump in utilization would be needed and most analysts are predicting the rig count to slowly rise to about the 1500-plus range for the fourth quarter.

  9. [Study on the automatic parameters identification of water pipe network model].

    PubMed

    Jia, Hai-Feng; Zhao, Qi-Feng

    2010-01-01

    Based on the problems analysis on development and application of water pipe network model, the model parameters automatic identification is regarded as a kernel bottleneck of model's application in water supply enterprise. The methodology of water pipe network model parameters automatic identification based on GIS and SCADA database is proposed. Then the kernel algorithm of model parameters automatic identification is studied, RSA (Regionalized Sensitivity Analysis) is used for automatic recognition of sensitive parameters, and MCS (Monte-Carlo Sampling) is used for automatic identification of parameters, the detail technical route based on RSA and MCS is presented. The module of water pipe network model parameters automatic identification is developed. At last, selected a typical water pipe network as a case, the case study on water pipe network model parameters automatic identification is conducted and the satisfied results are achieved.

  10. New technique for installing screen wicking into Inconel 718 heat pipe

    NASA Astrophysics Data System (ADS)

    Giriunas, Julius A.; Watson, Gordon K.; Tower, Leonard K.

    1993-01-01

    The creep behavior of superalloys, including Inconel 718, in the presence of liquid sodium is not yet known. To study this problem, the NASA Lewis Research Center has initiated a program with the Energy Technology Engineering Center (ETEC) of Rockwell International Corporation to fill with sodium and creep-test three small cylindrical heat pipes of Inconel 718 for a period of 1000 hours each. This report documents the design and the construction methods that were used at NASA Lewis to fabricate these heat pipes. Of particular importance in the heat pipe construction was the installation of the screen wicking by using an expandable mandrel and differential thermal expansion. This installation technique differs from anything known to have been reported in the heat pipe literature and may be of interest to other workers in the heat pipe field.

  11. New technique for installing screen wicking into Inconel 718 heat pipe

    SciTech Connect

    Giriunas, J.A.; Watson, G.K. ); Tower, L.K. )

    1993-01-10

    The creep behavior of superalloys, including Inconel 718, in the presence of liquid sodium is not yet known. To study this problem, the NASA Lewis Research Center has initiated a program with the Energy Technology Engineering Center (ETEC) of Rockwell International Corporation to fill with sodium and creep-test three small cylindrical heat pipes of Inconel 718 for a period of 1000 hours each. This report documents the design and the construction methods that were used at NASA Lewis to fabricate these heat pipes. Of particular importance in the heat pipe construction was the installation of the screen wicking by using an expandable mandrel and differential thermal expansion. This installation technique differs from anything known to have been reported in the heat pipe literature and may be of interest to other workers in the heat pipe field.

  12. Neutron Stars and Thermonuclear X-ray Bursts

    NASA Technical Reports Server (NTRS)

    Bhattacharyya, Supid

    2007-01-01

    This viewgraph presentation describes neutron stars and thermonuclear x ray bursts. The contents include: 1) Neutron Stars: why do we care?; 2) Thermonuclear Bursts: why do we care?; 3) Neutron Stars: Mass, Radius and Spin: a. Continuum Spectroscopy of Bursts b. Spectral Lines from Bursts c. Timing Properties of Bursts; 4) Neutron Star Atmosphere: Thermonuclear Flame Spreading; and 5) Future Prospects and Conclusions.

  13. Pipe crawler with extendable legs

    DOEpatents

    Zollinger, W.T.

    1992-06-16

    A pipe crawler for moving through a pipe in inchworm fashion having front and rear leg assemblies separated by air cylinders to increase and decrease the spacing between assemblies. Each leg of the four legs of an assembly is moved between a wall-engaging, extended position and a retracted position by a separate air cylinder. The air cylinders of the leg assemblies are preferably arranged in pairs of oppositely directed cylinders with no pair lying in the same axial plane as another pair. Therefore, the cylinders can be as long as a leg assembly is wide and the crawler can crawl through sections of pipes where the diameter is twice that of other sections. The crawler carries a valving system, a manifold to distribute air supplied by a single umbilical air hose to the various air cylinders in a sequence controlled electrically by a controller. The crawler also utilizes a rolling mechanism, casters in this case, to reduce friction between the crawler and pipe wall thereby further extending the range of the pipe crawler. 8 figs.

  14. Flexible ultrasonic pipe inspection apparatus

    DOEpatents

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

    1998-06-23

    A flexible, modular ultrasonic pipe inspection apparatus, comprises a flexible, hollow shaft that carries a plurality of modules, including at least one rotatable ultrasonic transducer, a motor/gear unit, and a position/signal encoder. The modules are connected by flexible knuckle joints that allow each module of the apparatus to change its relative orientation with respect to a neighboring module, while the shaft protects electrical wiring from kinking or buckling while the apparatus moves around a tight corner. The apparatus is moved through a pipe by any suitable means, including a tether or drawstring attached to the nose or tail, differential hydraulic pressure, or a pipe pig. The rotational speed of the ultrasonic transducer and the forward velocity of the apparatus are coordinated so that the beam sweeps out the entire interior surface of the pipe, enabling the operator to accurately assess the condition of the pipe wall and determine whether or not leak-prone corrosion damage is present. 7 figs.

  15. Pipe crawler with extendable legs

    DOEpatents

    Zollinger, William T.

    1992-01-01

    A pipe crawler for moving through a pipe in inchworm fashion having front and rear leg assemblies separated by air cylinders to increase and decrease the spacing between assemblies. Each leg of the four legs of an assembly is moved between a wall-engaging, extended position and a retracted position by a separate air cylinder. The air cylinders of the leg assemblies are preferably arranged in pairs of oppositely directed cylinders with no pair lying in the same axial plane as another pair. Therefore, the cylinders can be as long a leg assembly is wide and the crawler can crawl through sections of pipes where the diameter is twice that of other sections. The crawler carries a valving system, a manifold to distribute air supplied by a single umbilical air hose to the various air cylinders in a sequence controlled electrically by a controller. The crawler also utilizes a rolling mechanism, casters in this case, to reduce friction between the crawler and pipe wall thereby further extending the range of the pipe crawler.

  16. Acoustic Propagation in a Water-Filled Cylindrical Pipe

    SciTech Connect

    Sullivan, E J; Candy, J V

    2003-06-01

    This study was concerned with the physics of the propagation of a tone burst of high frequency sound in a steel water-filled pipe. The choice of the pulse was rather arbitrary, so that this work in no way can be considered as recommending a particular pulse form. However, the MATLAB computer codes developed in this study are general enough to carry out studies of pulses of various forms. Also, it should be pointed out that the codes as written are quite time consuming. A computation of the complete field, including all 5995 modes, requires several hours on a desktop computer. The time required by such computations as these is a direct consequence of the bandwidths, frequencies and sample rates employed. No attempt was made to optimize these codes, and it is assumed that much can be done in this regard.

  17. Transcriptional burst frequency and burst size are equally modulated across the human genome

    SciTech Connect

    Dar, Roy D.; Simpson, Michael L; Weinberger, Leor S.; Razooky, B; Cox, Chris D.; McCollum, James M.; Trimeloni, Tom; Singh, A

    2012-01-01

    Gene expression occurs either as an episodic process, characterized by pulsatile bursts or as a constitutive, Poisson-like accumulation of gene products. It is not clear which mode of gene expression (constitutive versus bursty) predominates across a genome or how transcriptional dynamics are influenced by genomic position and promoter sequence. Here, we use time-lapse fluorescence microscopy, building off of theoretical studies that exploit the time-resolved structure of stochastic fluctuations in gene expression, to develop a three-dimensional method for mapping underlying gene-regulatory mechanisms. Over 8,000 individual human genomic loci were analyzed, and at virtually all loci, episodic bursting as opposed to constitutive expression was found to be the predominant mode of expression. Quantitative analysis of the expression dynamics at these 8,000 loci indicates that both frequency and size of transcriptional bursts vary equally across the human genome independent of promoter sequence. Strikingly, weaker expression loci modulate burst frequency to increase activity, while stronger expression loci modulate burst size to increase activity. Transcriptional activators, such as TNF, generate similar patterns of change in burst frequency and burst size. In summary, transcriptional bursting dominates across the human genome, both burst frequency and burst size vary by chromosomal location, and transcriptional activators alter burst frequency and burst size, depending on the expression level of the locus.

  18. Laboratory evaluation of the Pipe Explorer{trademark} gamma measurement and deployment capability

    SciTech Connect

    Cremer, C.D.; Cramer, E.; Lowry, W.

    1994-08-01

    The DOE is faced with the responsibility of decommissioning and dismantling many of its nuclear process facilities. Much of this will involve piping systems which may or may not be contaminated with radioactive material. It is important to be able to differentiate contaminated from non-contaminated material, since the disposal costs for radioactive waste are significant (on the order of hundreds of dollars per cubic foot). In the case of pipes, this determination may be particularly difficult if the pipes are not easily accessible. As a solution to this problem, SEA is developing an inverting membrane technology, called Pipe Explorer{trademark} which uses commercial gamma spectroscopy systems to characterize the radiation levels inside of pipes. The heart of the system is an air-tight membrane which is initially spooled inside of a canister. The end of the membrane protruding out of the canister is folded over and attached to a basepipe. With this configuration, when the canister becomes pressurized the pressure force on the membrane causes the membrane to be pulled from the spool. This continues until the membrane is completely off the spool. A radiation detector is attached to the end of the membrane and towed into the pipe as the membrane continues to evert. The detector cabling is also towed into the pipe. To retrieve the system from a pipe the process is simply reversed, where the cabling, detector, and membrane are wound back onto the spool. The system can thus be used to move a detector freely back and forth through a pipe to provide high resolution analysis of the location of radioactive contamination in pipes. This unique method can deploy the detector and analyze piping systems with multiple elbows and vertical runs. The membrane also serves to protect the expensive detector from contamination.

  19. Flat heat pipe design, construction, and analysis

    SciTech Connect

    Voegler, G.; Boughey, B.; Cerza, M.; Lindler, K.W.

    1999-08-02

    This paper details the design, construction and partial analysis of a low temperature flat heat pipe in order to determine the feasibility of implementing flat heat pipes into thermophotovoltaic (TPV) energy conversion systems.

  20. Laboratory exercises on oscillation modes of pipes

    NASA Astrophysics Data System (ADS)

    Haeberli, Willy

    2009-03-01

    This paper describes an improved lab setup to study the vibrations of air columns in pipes. Features of the setup include transparent pipes which reveal the position of a movable microphone inside the pipe; excitation of pipe modes with a miniature microphone placed to allow access to the microphone stem for open, closed, or conical pipes; and sound insulation to avoid interference between different setups in a student lab. The suggested experiments on the modes of open, closed, and conical pipes, the transient response of a pipe, and the effect of pipe diameter are suitable for introductory physics laboratories, including laboratories for nonscience majors and music students, and for more advanced undergraduate laboratories. For honors students or for advanced laboratory exercises, the quantitative relation between the resonance width and damping time constant is of interest.

  1. Removing Camera Shake via Weighted Fourier Burst Accumulation.

    PubMed

    Delbracio, Mauricio; Sapiro, Guillermo

    2015-11-01

    Numerous recent approaches attempt to remove image blur due to camera shake, either with one or multiple input images, by explicitly solving an inverse and inherently ill-posed deconvolution problem. If the photographer takes a burst of images, a modality available in virtually all modern digital cameras, we show that it is possible to combine them to get a clean sharp version. This is done without explicitly solving any blur estimation and subsequent inverse problem. The proposed algorithm is strikingly simple: it performs a weighted average in the Fourier domain, with weights depending on the Fourier spectrum magnitude. The method can be seen as a generalization of the align and average procedure, with a weighted average, motivated by hand-shake physiology and theoretically supported, taking place in the Fourier domain. The method's rationale is that camera shake has a random nature, and therefore, each image in the burst is generally blurred differently. Experiments with real camera data, and extensive comparisons, show that the proposed Fourier burst accumulation algorithm achieves state-of-the-art results an order of magnitude faster, with simplicity for on-board implementation on camera phones. Finally, we also present experiments in real high dynamic range (HDR) scenes, showing how the method can be straightforwardly extended to HDR photography.

  2. 46 CFR 61.15-5 - Steam piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to a... removed and the piping thoroughly examined. (b) All steam piping subject to pressure from the main...

  3. 46 CFR 61.15-5 - Steam piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to a... removed and the piping thoroughly examined. (b) All steam piping subject to pressure from the main...

  4. 46 CFR 61.15-5 - Steam piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to a... removed and the piping thoroughly examined. (b) All steam piping subject to pressure from the main...

  5. 46 CFR 61.15-5 - Steam piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to a... removed and the piping thoroughly examined. (b) All steam piping subject to pressure from the main...

  6. 46 CFR 61.15-5 - Steam piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to a... removed and the piping thoroughly examined. (b) All steam piping subject to pressure from the main...

  7. Introduction to Loop Heat Pipes

    NASA Technical Reports Server (NTRS)

    Ku, Jentung

    2015-01-01

    This is the presentation file for the short course Introduction to Loop Heat Pipes, to be conducted at the 2015 Thermal Fluids and Analysis Workshop, August 3-7, 2015, Silver Spring, Maryland. This course will discuss operating principles and performance characteristics of a loop heat pipe. Topics include: 1) pressure profiles in the loop; 2) loop operating temperature; 3) operating temperature control; 4) loop startup; 4) loop shutdown; 5) loop transient behaviors; 6) sizing of loop components and determination of fluid inventory; 7) analytical modeling; 8) examples of flight applications; and 9) recent LHP developments.

  8. Cryogenic thermal diode heat pipes

    NASA Technical Reports Server (NTRS)

    Alario, J.

    1979-01-01

    The development of spiral artery cryogenic thermal diode heat pipes was continued. Ethane was the working fluid and stainless steel the heat pipe material in all cases. The major tasks included: (1) building a liquid blockage (blocking orifice) thermal diode suitable for the HEPP space flight experiment; (2) building a liquid trap thermal diode engineering model; (3) retesting the original liquid blockage engineering model, and (4) investigating the startup dynamics of artery cryogenic thermal diodes. An experimental investigation was also conducted into the wetting characteristics of ethane/stainless steel systems using a specially constructed chamber that permitted in situ observations.

  9. Heat pipe thermal conditioning panel

    NASA Technical Reports Server (NTRS)

    Saaski, E. W.; Loose, J. D.; Mccoy, K. E.

    1974-01-01

    Thermal control of electronic hardware and experiments on future space vehicles is critical to proper functioning and long life. Thermal conditioning panels (cold plates) are a baseline control technique in current conceptual studies. Heat generating components mounted on the panels are typically cooled by fluid flowing through integral channels within the panel. However, replacing the pumped fluid coolant loop within the panel with heat pipes offers attractive advantages in weight, reliability, and installation. This report describes the development and fabrication of two large 0.76 x 0.76 m heat pipe thermal conditioning panels to verify performance and establish the design concept.

  10. High performance flexible heat pipes

    NASA Technical Reports Server (NTRS)

    Shaubach, R. M.; Gernert, N. J.

    1985-01-01

    A Phase I SBIR NASA program for developing and demonstrating high-performance flexible heat pipes for use in the thermal management of spacecraft is examined. The program combines several technologies such as flexible screen arteries and high-performance circumferential distribution wicks within an envelope which is flexible in the adiabatic heat transport zone. The first six months of work during which the Phase I contract goal were met, are described. Consideration is given to the heat-pipe performance requirements. A preliminary evaluation shows that the power requirement for Phase II of the program is 30.5 kilowatt meters at an operating temperature from 0 to 100 C.

  11. Status of program to develop low cost application of carbon fiber to strengthen water and other pipes

    NASA Astrophysics Data System (ADS)

    Goodell, Ryan; Wisotzkey, Sean; Carr, Heath; Fyfe, Ed

    2012-04-01

    Currently, the United States has over 3.5 million4 linear feet of large diameter water pipes failing prematurely. Methods of pipe repair generally involve very intrusive excavation and replacement of existing pipe sections that can be slow, detrimental to society, and in a lot of cases impossible. A novel new approach of repair is under development that utilizes the latest technology in automated robotics to effectively retrofit the pipes with carbon fiber. By utilizing this technology, many of the problems associated with existing repair methods can be mitigated.

  12. Analysis of Municipal Pipe Network Franchise Institution

    NASA Astrophysics Data System (ADS)

    Yong, Sun; Haichuan, Tian; Feng, Xu; Huixia, Zhou

    Franchise institution of municipal pipe network has some particularity due to the characteristic of itself. According to the exposition of Chinese municipal pipe network industry franchise institution, the article investigates the necessity of implementing municipal pipe network franchise institution in China, the role of government in the process and so on. And this offers support for the successful implementation of municipal pipe network franchise institution in China.

  13. Central burst of simultaneously rotating and gravitating body

    NASA Astrophysics Data System (ADS)

    Golubyatnikov, A. N.; Chilachava, T. I.

    1984-04-01

    The astrophysical problem of bursts in simultaneously rotating and gravitating celestial bodies is treated as an axisymmetric one for a homogeneous ellipsoid bursting at the center. It is formulated in a system of spherical coordinates with the sought distributions of pressure and gravitational potential appropriately stipulated. The corresponding equations of steady axisymmetric adiabatic motion of a gas during the initial stage, before the shock wave reaches the surface, are formulated in Lagrange variables and by the asymptotic method of a thin shock layer with epsilon = upsilon -1 as the small parameter upsilon- adiabatic exponent) and with appropriate boundary conditions at the shock wave front. Consideration is taken of the law of momentum conservation and the condition of continuity for the tangential velocity component as well as for Euler and Lagrange variables. Emergence of the shock wave at the body surface, at the poles first, results in formation of jets associated with expansion of a gas into vacuum.

  14. Air bubble bursting effect of lotus leaf.

    PubMed

    Wang, Jingming; Zheng, Yongmei; Nie, Fu-Qiang; Zhai, Jin; Jiang, Lei

    2009-12-15

    In this paper, a phenomenon of air bubbles quickly bursting within several milliseconds on a "self-cleaning" lotus leaf was described. This observation prompted the synthesis of artificial surfaces similar to that of the lotus leaf. The artificial leaf surfaces, prepared by photolithography and wet etching, showed a similar air bubble bursting effect. Smooth and rough silicon surfaces with an ordered nanostructure or patterned microstructure were utilized to study the contribution of the micro/nano hierarchical structures to this phenomenon of air bubble bursting. Air bubbles were found to burst on some superhydrophobic surfaces with microstructure (within 220 ms). However, air bubbles burst much more rapidly (within 13 ms) on similar surfaces with micro/nanostructure. The height, width, and spacing of hierarchical structures could also affect air bubble bursting, and the effect of the height was more obvious. When the height of hierarchical structures was around the height found in natural lotus papillae, the width and spacing were significant for air bubble bursting. An original model was proposed to further evaluate the reason why the micro/nano hierarchical rough structures had an excellent air bubble bursting effect, and the validity of the model was theoretically demonstrated.

  15. Backscattering of solar electron burst distributions

    NASA Astrophysics Data System (ADS)

    Skoug, R. M.; Steinberg, J. T.; Anderson, B. R.; de Koning, C. A.; Gosling, J. T.; McComas, D. J.

    2008-12-01

    Solar electron bursts are frequently observed in the ACE/SWEPAM suprathermal electron measurements at energies below 1.4 keV. Approximately 1/3 of such events show backstreaming electrons, which are typically observed after a 1-2 hour delay following burst onset and travel back towards the Sun along the magnetic field direction. These backstreaming particles are likely produced by scattering of the solar electron burst particles beyond the ~1 AU spacecraft location. Our previous studies have shown that transient solar burst electrons exhibit a greater degree of pitch angle scattering than does the steady-state solar wind electron strahl, which could result in turning back of the burst electrons. From the delays observed between the onset of the bursts and the backstreaming, we infer that burst electrons are turned back sunward at a field-aligned distance of less than 1 AU beyond the spacecraft. In this study we compare the fluxes and energy spectra of backstreaming particles with those of the outgoing burst particles. In addition, we compare the angular widths of the two electron beams. These comparisons provide an indication of the relative importance of magnetic mirroring and focusing, scattering in pitch angle, and scattering in energy for determining the character of the observed electron distributions.

  16. Astronomy: Radio burst caught red-handed

    NASA Astrophysics Data System (ADS)

    Falcke, Heino

    2017-01-01

    For almost a decade, astronomers have observed intense bursts of radio waves from the distant cosmos whose origins were unknown. The source of one such burst has now been identified, but this has only deepened the mystery. See Letter p.58

  17. The Burst Mode of Protostellar Accretion

    NASA Astrophysics Data System (ADS)

    Vorobyov, E. I.; Basu, Shantanu

    2006-10-01

    We present new numerical simulations in the thin disk approximation that characterize the burst mode of protostellar accretion. The burst mode begins upon the formation of a centrifugally balanced disk around a newly formed protostar. It comprises prolonged quiescent periods of low accretion rate (typically <~10-7 Msolar yr-1) that are punctuated by intense bursts of accretion (typically >~10-4 Msolar yr-1, with duration <~100 yr) during which most of the protostellar mass is accumulated. The accretion bursts are associated with the formation of dense protostellar/protoplanetary embryos, which are later driven onto the protostar by the gravitational torques that develop in the disk. Gravitational instability in the disk, driven by continuing infall from the envelope, is shown to be an effective means of transporting angular momentum outward and mass inward to the protostar. We show that the disk mass always remains significantly less than the central protostar's mass throughout this process. The burst phenomenon is robust enough to occur for a variety of initial values of rotation rate and frozen-in (supercritical) magnetic field and a variety of density-temperature relations. Even in cases where the bursts are nearly entirely suppressed, a moderate increase in cloud size or rotation rate can lead to vigorous burst activity. We conclude that most (if not all) protostars undergo a burst mode of evolution during their early accretion history, as inferred empirically from observations of FU Orionis variables.

  18. Physics issues of gamma ray burst emissions

    NASA Technical Reports Server (NTRS)

    Liang, Edison

    1987-01-01

    The critical physics issues in the interpretation of gamma-ray-burst spectra are reviewed. An attempt is made to define the emission-region parameter space satisfying the maximum number of observational and theoretical constraints. Also discussed are the physical mechanisms responsible for the bursts that are most consistent with the above parameter space.

  19. Autaptic Connections Shift Network Excitability and Bursting

    PubMed Central

    Wiles, Laura; Gu, Shi; Pasqualetti, Fabio; Parvesse, Brandon; Gabrieli, David; Bassett, Danielle S.; Meaney, David F.

    2017-01-01

    We examine the role of structural autapses, when a neuron synapses onto itself, in driving network-wide bursting behavior. Using a simple spiking model of neuronal activity, we study how autaptic connections affect activity patterns, and evaluate if controllability significantly affects changes in bursting from autaptic connections. Adding more autaptic connections to excitatory neurons increased the number of spiking events and the number of network-wide bursts. We observed excitatory synapses contributed more to bursting behavior than inhibitory synapses. We evaluated if neurons with high average controllability, predicted to push the network into easily achievable states, affected bursting behavior differently than neurons with high modal controllability, thought to influence the network into difficult to reach states. Results show autaptic connections to excitatory neurons with high average controllability led to higher burst frequencies than adding the same number of self-looping connections to neurons with high modal controllability. The number of autapses required to induce bursting was lowered by adding autapses to high degree excitatory neurons. These results suggest a role of autaptic connections in controlling network-wide bursts in diverse cortical and subcortical regions of mammalian brain. Moreover, they open up new avenues for the study of dynamic neurophysiological correlates of structural controllability. PMID:28266594

  20. Thermal Performance of High Temperature Titanium - Water Heat Pipes by Multiple Heat Pipe Manufacturers

    NASA Astrophysics Data System (ADS)

    Sanzi, James L.

    2007-01-01

    Titanium - water heat pipes are being investigated for use in heat rejection systems for lunar and Mars fission surface power systems. Heat pipes provide an efficient and reliable means to transfer heat to a radiator heat rejection system. NASA Glenn Research Center requisitioned nine titanium water heat pipes from three vendors. Each vendor supplied three heat pipes 1.25 cm diameter by 1.1 meter long with each vendor selecting a different wick design. Each of the three heat pipes is slightly different in construction. Additional specifications for the heat pipes included 500 K nominal operating temperature, light weight, and freeze tolerance. The heat pipes were performance tested gravity aided, in the horizontal position and elevations against gravity at 450 K and 500 K. Performance of the three heat pipes is compared. The heat pipe data will be used to verify models of heat pipe radiators that will be used in future space exploration missions.

  1. Thermal Performance of High Temperature Titanium-Water Heat Pipes by Multiple Heat Pipe Manufacturers

    NASA Technical Reports Server (NTRS)

    Sanzi, James L.

    2007-01-01

    Titanium-water heat pipes are being investigated for use in heat rejection systems for lunar and Mars fission surface power systems. Heat pipes provide an efficient and reliable means to transfer heat to a radiator heat rejection system. NASA Glenn Research Center requisitioned nine titanium water heat pipes from three vendors. Each vendor supplied three heat pipes 1.25 cm diameter by 1.1 meter long with each vendor selecting a different wick design. Each of the three heat pipes is slightly different in construction. Additional specifications for the heat pipes included 500 K nominal operating temperature, light weight, and freeze tolerance. The heat pipes were performance tested gravity-aided, in the horizontal position and at elevations against gravity at 450 and 500 K. Performance of the three heat pipes is compared. The heat pipe data will be used to verify models of heat pipe radiators that will be used in future space exploration missions.

  2. Thermal Performance of High Temperature Titanium -- Water Heat Pipes by Multiple Heat Pipe Manufacturers

    NASA Technical Reports Server (NTRS)

    Sanzi, James L.

    2007-01-01

    Titanium - water heat pipes are being investigated for use in heat rejection systems for lunar and Mars fission surface power systems. Heat pipes provide an efficient and reliable means to transfer heat to a radiator heat rejection system. NASA Glenn Research Center requisitioned nine titanium water heat pipes from three vendors. Each vendor supplied three heat pipes 1.25 cm diameter by 1.1 meter long with each vendor selecting a different wick design. Each of the three heat pipes is slightly different in construction. Additional specifications for the heat pipes included 500 K nominal operating temperature, light weight, and freeze tolerance. The heat pipes were performance tested gravity-aided, in the horizontal position and at elevations against gravity at 450 K and 500 K. Performance of the three heat pipes is compared. The heat pipe data will be used to verify models of heat pipe radiators that will be used in future space exploration missions.

  3. 46 CFR 76.25-30 - Piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Automatic Sprinkling System, Details § 76.25-30 Piping. (a) All piping, valves, and fittings of ferrous materials shall be... piping, valves, fittings, and sprinkler heads shall be securely supported, and, where...

  4. 46 CFR 154.660 - Pipe welding.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Pipe welding. 154.660 Section 154.660 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR... § 154.660 Pipe welding. (a) Pipe welding must meet part 57 of this chapter. (b) Longitudinal butt...

  5. 46 CFR 154.660 - Pipe welding.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Pipe welding. 154.660 Section 154.660 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR... § 154.660 Pipe welding. (a) Pipe welding must meet part 57 of this chapter. (b) Longitudinal butt...

  6. 46 CFR 154.660 - Pipe welding.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Pipe welding. 154.660 Section 154.660 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR... § 154.660 Pipe welding. (a) Pipe welding must meet Part 57 of this chapter. (b) Longitudinal butt...

  7. 46 CFR 154.660 - Pipe welding.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Pipe welding. 154.660 Section 154.660 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR... § 154.660 Pipe welding. (a) Pipe welding must meet part 57 of this chapter. (b) Longitudinal butt...

  8. 46 CFR 108.447 - Piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Piping. 108.447 Section 108.447 Shipping COAST GUARD, 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,...

  9. 46 CFR 197.336 - Pressure piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Pressure piping. 197.336 Section 197.336 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.336 Pressure piping. Piping systems that are not an integral part of the vessel or facility, carrying fluids under pressures exceeding 15...

  10. 46 CFR 197.336 - Pressure piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Pressure piping. 197.336 Section 197.336 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.336 Pressure piping. Piping systems that are not an integral part of the vessel or facility, carrying fluids under pressures exceeding 15...

  11. 46 CFR 197.336 - Pressure piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Pressure piping. 197.336 Section 197.336 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.336 Pressure piping. Piping systems that are not an integral part of the vessel or facility, carrying fluids under pressures exceeding 15...

  12. 46 CFR 197.336 - Pressure piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Pressure piping. 197.336 Section 197.336 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.336 Pressure piping. Piping systems that are not an integral part of the vessel or facility, carrying fluids under pressures exceeding 15...

  13. 46 CFR 197.336 - Pressure piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Pressure piping. 197.336 Section 197.336 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.336 Pressure piping. Piping systems that are not an integral part of the vessel or facility, carrying fluids under pressures exceeding 15...

  14. 46 CFR 182.455 - Fuel piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Fuel piping. 182.455 Section 182.455 Shipping COAST...) MACHINERY INSTALLATION Specific Machinery Requirements § 182.455 Fuel piping. (a) Materials and workmanship. The materials and construction of fuel lines, including pipe, tube, and hose, must comply with...

  15. 46 CFR 182.455 - Fuel piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Fuel piping. 182.455 Section 182.455 Shipping COAST...) MACHINERY INSTALLATION Specific Machinery Requirements § 182.455 Fuel piping. (a) Materials and workmanship. The materials and construction of fuel lines, including pipe, tube, and hose, must comply with...

  16. 46 CFR 182.455 - Fuel piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Fuel piping. 182.455 Section 182.455 Shipping COAST...) MACHINERY INSTALLATION Specific Machinery Requirements § 182.455 Fuel piping. (a) Materials and workmanship. The materials and construction of fuel lines, including pipe, tube, and hose, must comply with...

  17. 46 CFR 182.455 - Fuel piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Fuel piping. 182.455 Section 182.455 Shipping COAST...) MACHINERY INSTALLATION Specific Machinery Requirements § 182.455 Fuel piping. (a) Materials and workmanship. The materials and construction of fuel lines, including pipe, tube, and hose, must comply with...

  18. 46 CFR 119.455 - Fuel piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Fuel piping. 119.455 Section 119.455 Shipping COAST... Machinery Requirements § 119.455 Fuel piping. (a) Materials and workmanship. The materials and construction of fuel lines, including pipe, tube, and hose, must comply with the requirements of this...

  19. 46 CFR 119.455 - Fuel piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Fuel piping. 119.455 Section 119.455 Shipping COAST... Machinery Requirements § 119.455 Fuel piping. (a) Materials and workmanship. The materials and construction of fuel lines, including pipe, tube, and hose, must comply with the requirements of this...

  20. 46 CFR 119.455 - Fuel piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Fuel piping. 119.455 Section 119.455 Shipping COAST... Machinery Requirements § 119.455 Fuel piping. (a) Materials and workmanship. The materials and construction of fuel lines, including pipe, tube, and hose, must comply with the requirements of this...

  1. 46 CFR 119.455 - Fuel piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Fuel piping. 119.455 Section 119.455 Shipping COAST... Machinery Requirements § 119.455 Fuel piping. (a) Materials and workmanship. The materials and construction of fuel lines, including pipe, tube, and hose, must comply with the requirements of this...

  2. 46 CFR 119.455 - Fuel piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Fuel piping. 119.455 Section 119.455 Shipping COAST... Machinery Requirements § 119.455 Fuel piping. (a) Materials and workmanship. The materials and construction of fuel lines, including pipe, tube, and hose, must comply with the requirements of this...

  3. 49 CFR 192.59 - Plastic pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe... specification; and (2) It is resistant to chemicals with which contact may be anticipated. (b) Used plastic...

  4. 49 CFR 192.59 - Plastic pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe... specification; and (2) It is resistant to chemicals with which contact may be anticipated. (b) Used plastic...

  5. 49 CFR 192.59 - Plastic pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe... specification; and (2) It is resistant to chemicals with which contact may be anticipated. (b) Used plastic...

  6. 49 CFR 192.59 - Plastic pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe... specification; and (2) It is resistant to chemicals with which contact may be anticipated. (b) Used plastic...

  7. 49 CFR 192.59 - Plastic pipe.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe... specification; and (2) It is resistant to chemicals with which contact may be anticipated. (b) Used plastic...

  8. Leachate storage transport tanker loadout piping

    SciTech Connect

    Whitlock, R.W.

    1994-10-05

    This report contains schematic drawings for the pipe fittings for the Hanford waste tanks. Included are the modifications to the W-025 trench {number_sign}31 leachate loadout piping, and also the modifications to the tanker trailers. The piping was modified to prevent spillage to the environment. The tankers were modified for loading and unloading purposes.

  9. 33 CFR 127.1101 - Piping systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Piping systems. 127.1101 Section... Waterfront Facilities Handling Liquefied Hazardous Gas Design and Construction § 127.1101 Piping systems. Each piping system within the marine transfer area for LHG used for the transfer of LHG must meet...

  10. 46 CFR 95.17-15 - Piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Piping. 95.17-15 Section 95.17-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS FIRE PROTECTION EQUIPMENT Foam Extinguishing Systems, Details § 95.17-15 Piping. (a) All piping, valves, and fittings shall meet the...

  11. 46 CFR 76.17-15 - Piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Piping. 76.17-15 Section 76.17-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Foam Extinguishing Systems, Details § 76.17-15 Piping. (a) All piping, valves, and fittings shall meet the...

  12. Bag Test Measures Leakage From Insulated Pipe

    NASA Technical Reports Server (NTRS)

    Schock, Kent D.; Easter, Barry P.

    1994-01-01

    Test quantifies leakage of gas from pipe even though pipe covered with insulation. Involves use of helium analyzer to measure concentration of helium in impermeable bag around pipe. Test administered after standard soap-solution bubble test indicates presence and general class of leakage.

  13. 46 CFR 154.660 - Pipe welding.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Pipe welding. 154.660 Section 154.660 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR... § 154.660 Pipe welding. (a) Pipe welding must meet Part 57 of this chapter. (b) Longitudinal butt...

  14. FRBCAT: The Fast Radio Burst Catalogue

    NASA Astrophysics Data System (ADS)

    Petroff, E.; Barr, E. D.; Jameson, A.; Keane, E. F.; Bailes, M.; Kramer, M.; Morello, V.; Tabbara, D.; van Straten, W.

    2016-09-01

    Here, we present a catalogue of known Fast Radio Burst sources in the form of an online catalogue, FRBCAT. The catalogue includes information about the instrumentation used for the observations for each detected burst, the measured quantities from each observation, and model-dependent quantities derived from observed quantities. To aid in consistent comparisons of burst properties such as width and signal-to-noise ratios, we have re-processed all the bursts for which we have access to the raw data, with software which we make available. The originally derived properties are also listed for comparison. The catalogue is hosted online as a Mysql database which can also be downloaded in tabular or plain text format for off-line use. This database will be maintained for use by the community for studies of the Fast Radio Burst population as it grows.

  15. Backstreaming Electrons Associated With Solar Electron Bursts

    NASA Astrophysics Data System (ADS)

    Skoug, R. M.; Steinberg, J. T.; de Koning, C. A.; Gosling, J. T.; McComas, D. J.

    2007-12-01

    Solar electron bursts are frequently observed in the ACE/SWEPAM suprathermal electron measurements at energies below 1.4 keV. A significant fraction of such events show backscattered electrons, beginning after the burst onset and traveling back towards the Sun along the magnetic field direction. Such backscattered particles imply a scattering mechanism beyond the spacecraft location. Some bursts also show backstreaming conic distributions, implying mirroring at magnetic field enhancements beyond the spacecraft. Here we present a study of these backstreaming particles during solar electron events. We examine the occurrence of backstreaming electrons and their relationship to other burst characteristics such as pitch angle width, duration, and energy range. We also investigate the time delay between burst onset and the appearance of backscattered electrons, including energy and pitch-angle dispersion. We examine the pitch angle distribution and energy dependence of backstreaming electrons, and consider possible origins of these electron distributions and their relationship to solar wind structure beyond the spacecraft.

  16. Ginga Gamma-Ray Burst Line Occurrence

    NASA Technical Reports Server (NTRS)

    Band, David

    1998-01-01

    The purpose of this project is the statistical evaluation of the occurrence of spectral lines in the gamma-ray burst spectra detected by the Ginga burst detector, and the comparison of the Ginga results to the BATSE observations. Two significant line features were detected in the Ginga bursts, but thus far none have been detected in the bursts BATSE detected. These line features may indicate the presence of strong magnetic fields in bursts, and therefore are important physical diagnostics of the conditions in the plasma which radiates the observed gamma-rays. The issue is whether there is a discrepancy between the Ginga and BATSE results; the potential discrepancy must be evaluated statistically. Even if BATSE line detections are announced, the statistical methodology we have developed can be used to estimate the rate at which different types of spectral features occur.

  17. Gamma ray bursts: a 1983 overview

    SciTech Connect

    Cline, T.L.

    1983-10-01

    Gamma ray burst observations are reviewed with mention of new gamma-ray and optical transient measurements and with discussions of the controversial, contradictory and unresolved issues that have recently emerged: burst spectra appear to fluctuate in time as rapidly as they are measured, implying that any one spectrum may be incorrect. Energy spectra can be obligingly fitted to practically any desired shape, implying, in effect, that no objective spectral resolution exists at all. Burst fluxes and temporal quantities, including the total event energy, are characterized very differently with differing instruments, implying that even elementary knowledge of their properties is instrumentally subjective. Finally, the log N-log S determinations are deficient in the weak bursts, while there is no detection of a source direction anisotropy, implying that Ptolemy was right or that burst source distance estimates are basically guesswork. These issues may remain unsolved until vastly improved instruments are flown.

  18. Gamma Ray Bursts: a 1983 Overview

    NASA Technical Reports Server (NTRS)

    Cline, T. L.

    1983-01-01

    Gamma ray burst observations are reviewed with mention of new gamma-ray and optical transient measurements and with discussions of the controversial, contradictory and unresolved issues that have recently emerged: burst spectra appear to fluctuate in time as rapidly as they are measured, implying that any one spectrum may be incorrect; energy spectra can be obligingly fitted to practically any desired shape, implying, in effect, that no objective spectral resolution exists at all; burst fluxes and temporal quantities, including the total event energy, are characterized very differently with differing instruments, implying that even elementary knowledge of their properties is instrumentally subjective; finally, the log N-log S determinations are deficient in the weak bursts, while there is no detection of a source direction anisotropy, implying that Ptolemy was right or that burst source distance estimates are basically guesswork. These issues may remain unsolved until vastly improved instruments are flown.

  19. Microsecond flares in gamma-ray bursts

    NASA Technical Reports Server (NTRS)

    Schaefer, Bradley E.; Cohen, Justin; Teegarden, Bonnard J.; Cline, Thomas L.; Fishman, Gerald J.; Meegan, Charles A.; Wilson, Robert B.; Paciesas, William S.; Pendleton, Geoffrey N.; Matteson, James L.

    1993-01-01

    It has been suggested that gamma-ray burst light curves may consist of many superposed flares with a duration shorter than 30/microsec. If true, the implications for the interpretation of burst data are enormous. With the launch of the Compton Gamma-Ray Observatory, four predictions of Mitrofanov's (1989) suggestion can be tested. Our results which contradict this suggestion are (1) the photon arrival times are not correlated between independent detectors, (2) the spectral hardness and intensity does not depend on the detector area, (3) the bursts seen by detectors which measure photon positions do not see microsecond flares, and (4) burst positions deduced from detectors with different projected areas are close to the positions deduced from time-of-flight differences between separated spacecraft. We conclude, therefore, that gamma-ray bursts are not composed of microsecond flares.

  20. Stress Indices and Flexibility Factors for 90-Degree Piping Elbows with Straight Pipe Extensions.

    DTIC Science & Technology

    1982-02-01

    FACTORS FOR 90-DEGREE PIPING ELBOWS WITH STRAIGHT PIPE EXTENS IONS cn by oA. J. Quezon and G. C. Everstine a% APPROVED FOR PUBLIC RELEASE: DISTRIBUTION...FLEXIBILITY FACTORS FOR 90-DEGREE PIPING ELBOWS WITH STRAIGHT PIPE EXTENSIONS 6. PERFORMING OrG. REPORT NUMBER = 7. AUTHOR(e S. CONTRACT OR GRANT NUMBER(e...NOTES 19. KEY WORDS (Continue on reverse elde If neceeeary and Identify by bloc, number) Piping Finite Element Flexibility Factor Elbow NASTRAN Bend

  1. Pyrosequencing analysis of bacterial communities in biofilms from different pipe materials in a city drinking water distribution system of East China.

    PubMed

    Ren, Hongxing; Wang, Wei; Liu, Yan; Liu, Shuai; Lou, Liping; Cheng, Dongqing; He, Xiaofang; Zhou, Xiaoyan; Qiu, Shangde; Fu, Liusong; Liu, Jingqing; Hu, Baolan

    2015-12-01

    Biofilms in drinking water distribution systems (DWDSs) could cause several types of problems, such as the deterioration of water quality, corrosion of pipe walls, and potential proliferation of opportunistic pathogens. In this study, ten biofilm samples from different pipe materials, including ductile cast iron pipe (DCIP), gray cast iron pipe (GCIP), galvanized steel pipe (GSP), stainless steel clad pipe (SSCP), and polyvinyl chloride (PVC), were collected from an actual DWDS to investigate the effect of pipe material on bacterial community. Real-time quantitative polymerase chain reaction (qPCR) and culture-based method were used to quantify bacteria. 454 pyrosequencing was used for bacterial community analysis. The results showed that the numbers of total bacteria and culturable heterotrophic bacteria from iron pipes were higher than that in PVC, while the numbers of Shigella and vibrios were low in biofilms from iron pipes. Bacterial community analysis showed that Hyphomicrobium or Desulfovibrio were the predominant microorganism in iron pipes, whereas Sphingomonas or Pseudomonas were dominant in other types of pipe. This study revealed differences in bacterial communities in biofilms among different pipe materials, and the results were useful for pipeline material selection in DWDSs.

  2. Spatiotemporal chaos from bursting dynamics

    SciTech Connect

    Berenstein, Igal; De Decker, Yannick

    2015-08-14

    In this paper, we study the emergence of spatiotemporal chaos from mixed-mode oscillations, by using an extended Oregonator model. We show that bursting dynamics consisting of fast/slow mixed mode oscillations along a single attractor can lead to spatiotemporal chaotic dynamics, although the spatially homogeneous solution is itself non-chaotic. This behavior is observed far from the Hopf bifurcation and takes the form of a spatiotemporal intermittency where the system locally alternates between the fast and the slow phases of the mixed mode oscillations. We expect this form of spatiotemporal chaos to be generic for models in which one or several slow variables are coupled to activator-inhibitor type of oscillators.

  3. Pipe Leak Detection Technology Development

    EPA Science Inventory

    The U. S. Environmental Protection Agency (EPA) has determined that one of the nation’s biggest infrastructural needs is the replacement or rehabilitation of the water distribution and transmission systems. The institution of more effective pipe leak detection technology will im...

  4. Pipe inspection and repair system

    NASA Technical Reports Server (NTRS)

    Schempf, Hagen (Inventor); Mutschler, Edward (Inventor); Chemel, Brian (Inventor); Boehmke, Scott (Inventor); Crowley, William (Inventor)

    2004-01-01

    A multi-module pipe inspection and repair device. The device includes a base module, a camera module, a sensor module, an MFL module, a brush module, a patch set/test module, and a marker module. Each of the modules may be interconnected to construct one of an inspection device, a preparation device, a marking device, and a repair device.

  5. Radiant heating tests of several liquid metal heat-pipe sandwich panels

    NASA Technical Reports Server (NTRS)

    Camarda, C. J.; Basiulis, A.

    1983-01-01

    Integral heat-pipe sandwich panels, which synergistically combine the thermal efficiency of heat pipes and the structural efficiency of honeycomb sandwich construction, were conceived as a means of alleviating thermal stress problems in the Langley Scramjet Engine. Test panels which utilized two different wickable honeycomb cores, facesheets with screen mesh sintered to the internal surfaces, and a liquid metal working fluid (either sodium or potassium) were tested by radiant heating at various heat-load levels. The heat-pipe panels reduced maximum temperature differences by 31 percent with sodium working fluid and 45 percent with potassium working fluid. Results indicate that a heat-pipe sandwich panel is a potential, simple solution to the engine thermal stress problem. Other interesting applications of the concept include: cold plates for electronic component and circuit card cooling, radiators for large space platforms, low-distortion large area structures (e.g., space antennas) and laser mirrors.

  6. Radiant heating tests of several liquid metal heat-pipe sandwich panels

    SciTech Connect

    Camarda, C.J.; Basiulis, A.

    1983-08-01

    Integral heat pipe sandwich panels, which synergistically combine the thermal efficiency of heat pipes and the structural efficiency of honeycomb sandwich construction, were conceived as a means of alleviating thermal stress problems in the Langley Scramjet Engine. Test panels which utilized two different wickable honeycomb cores, facesheets with screen mesh sintered to the internal surfaces, and a liquid metal working fluid (either sodium or potassium) were tested by radiant heating at various heat load levels. The heat pipe panels reduced maximum temperature differences by 31 percent with sodium working fluid and 45 percent with potassium working fluid. Results indicate that a heat pipe sandwich panel is a potential, simple solution to the engine thermal stress problem. Other interesting applications of the concept include: cold plates for electronic component and circuit card cooling, radiators for large space platforms, low distortion large area structures (e.g., space antennas) and laser mirrors.

  7. Diffusion-controlled startup of a gas-loaded liquid-metal heat pipe

    NASA Astrophysics Data System (ADS)

    Ponnappan, R.; Boehman, L. I.; Mahefkey, E. T.

    1990-07-01

    Liquid-metal heat pipes have exhibited difficulties starting up from a frozen-state. Inert gas loading is a possible solution to the frozen-state startup problem. The present study deals with the diffusion-controlled startup analysis and testing of an argon-loaded, 2-m-long, stainless steel-sodium heat pipe of the double-walled type with artery channel and long adiabatic section. A two-dimensional, quasi-steady state, binary vapor-gas diffusion model determined the energy transport rate of vapor at the diffusion front. The analytical solution to the diffusion problem provided the vapor flux, which in turn was used in the one-dimensional transient thermal model of the heat pipe to predict the time rate-of-change of temperature and position of the hot front. The experimental test results successfully demonstrated the startup of a gas-loaded sodium heat pipe and validated the diffusion model of the startup.

  8. Radiant heating tests of several liquid metal heat-pipe sandwich panels

    NASA Technical Reports Server (NTRS)

    Camarda, C. J.; Basiulis, A.

    1983-01-01

    Integral heat pipe sandwich panels, which synergistically combine the thermal efficiency of heat pipes and the structural efficiency of honeycomb sandwich construction, were conceived as a means of alleviating thermal stress problems in the Langley Scramjet Engine. Test panels which utilized two different wickable honeycomb cores, facesheets with screen mesh sintered to the internal surfaces, and a liquid metal working fluid (either sodium or potassium) were tested by radiant heating at various heat load levels. The heat pipe panels reduced maximum temperature differences by 31 percent with sodium working fluid and 45 percent with potassium working fluid. Results indicate that a heat pipe sandwich panel is a potential, simple solution to the engine thermal stress problem. Other interesting applications of the concept include: cold plates for electronic component and circuit card cooling, radiators for large space platforms, low distortion large area structures (e.g., space antennas) and laser mirrors.

  9. Heat pipes in space and on earth

    NASA Technical Reports Server (NTRS)

    Ollendorf, S.

    1978-01-01

    The performance of heat pipes used in the thermal control system of spacecraft such as OAO-III and ATS-6 is discussed, and applications of heat pipes to permafrost stabilization on the Alaska Pipeline and to heat recovery systems are described. Particular attention is given to the ATS-6, launched in 1974, which employs 55 heat pipes to carry solar and internal power loads to radiator surfaces. In addition, experiments involving radiative cooling based on cryogenic heat pipes have been planned for the Long Duration Exposure Facility spacecraft and for Spacelab. The role of heat pipes in Space Shuttle heat rejection services is also mentioned.

  10. Observing a Burst with Sunglasses

    NASA Astrophysics Data System (ADS)

    2003-11-01

    Unique Five-Week VLT Study of the Polarisation of a Gamma-Ray Burst Afterglow "Gamma-ray bursts (GRBs)" are certainly amongst the most dramatic events known in astrophysics. These short flashes of energetic gamma-rays, first detected in the late 1960's by military satellites, last from less than one second to several minutes. GRBs have been found to be situated at extremely large ("cosmological") distances. The energy released in a few seconds during such an event is larger than that of the Sun during its entire lifetime of more than 10,000 million years. The GRBs are indeed the most powerful events since the Big Bang known in the Universe, cf. ESO PR 08/99 and ESO PR 20/00. During the past years circumstantial evidence has mounted that GRBs signal the collapse of extremely massive stars, the so-called hypernovae. This was finally demonstrated some months ago when astronomers, using the FORS instrument on ESO's Very Large Telescope (VLT), documented in unprecedented detail the changes in the spectrum of the light source ("the optical afterglow") of the gamma-ray burst GRB 030329 (cf. ESO PR 16/03). A conclusive and direct link between cosmological gamma-ray bursts and explosions of very massive stars was provided on this occasion. Gamma-Ray Burst GRB 030329 was discovered on March 29, 2003 by NASA's High Energy Transient Explorer spacecraft. Follow-up observations with the UVES spectrograph at the 8.2-m VLT KUEYEN telescope at the Paranal Observatory (Chile) showed the burst to have a redshift of 0.1685 [1]. This corresponds to a distance of about 2,650 million light-years, making GRB 030329 the second-nearest long-duration GRB ever detected. The proximity of GRB 030329 resulted in very bright afterglow emission, permitting the most extensive follow-up observations of any afterglow to date. A team of astronomers [2] led by Jochen Greiner of the Max-Planck-Institut für extraterrestrische Physik (Germany) decided to make use of this unique opportunity to study the

  11. Practical aspects of acoustic plastic pipe location

    SciTech Connect

    Huebler, J.E.; Campbell, B.K.; Ching, G.K.

    1993-12-31

    Many gas distribution company operation and maintenance activities require precise knowledge of the location of buried plastic piping. Plastic pipe cannot be located if the tracer wire is gone or was never installed. Under sponsorship of the Southern California Gas Company, IGT successfully demonstrated an acoustic plastic pipe location technique and is developing the technique into a practical field instrument an acoustic signal is injected directly into the gas at a service. The acoustic signal travels in the gas in the pipes, not in the pipe wall. As the acoustic wave travels along the pipe, some of the sound radiates from the pipe through the soil to the surface of the ground. An array of sensors on the surface of the ground perpendicular to the pipe detects the acoustic signal, thereby locating the Pipe. Two different acoustic measurements are used. The first measurement locates the pipe to within {plus_minus} 3-ft. Then the second technique determines the location of the pipe to within {plus_minus} 6-in.

  12. Underground pipe inspection device and method

    DOEpatents

    Germata, Daniel Thomas

    2009-02-24

    A method and apparatus for inspecting the walls of an underground pipe from inside the pipe in which an inspection apparatus having a circular planar platform having a plurality of lever arms having one end pivotably attached to one side of the platform, having a pipe inspection device connected to an opposite end, and having a system for pivoting the lever arms is inserted into the underground pipe, with the inspection apparatus oriented with the planar platform disposed perpendicular to the pipe axis. The plurality of lever arms are pivoted toward the inside wall of the pipe, contacting the inside wall with each inspection device as the apparatus is conveyed along a length of the underground pipe.

  13. Through Weld Inspection of Wrought Stainless Steel Piping Using Phased Arrays

    SciTech Connect

    Anderson, Michael T.; Cumblidge, Stephen E.; Doctor, Steven R.

    2004-12-31

    Outline: Discuss far-side weld problem and phased array techniques applied. Describe laboratory work on flawed piping specimens using L- and S-wave arrays and provide synopsis of results. Discuss conclusions ofr capability of phased array as applied to austenitic welds. Research Approach: Evaluate phased arrays on unifornly-welded piping specimens. Apply best methods to non-uniform welds. Correlate acoustic responses as function of weld microstructures.

  14. Development of a curved pipe capability for the NASTRAN finite element program

    NASA Technical Reports Server (NTRS)

    Jeter, J. W., Jr.

    1977-01-01

    A curved pipe element capability for the NASTRAN structural analysis program is developed using the NASTRAN dummy element feature. A description is given of the theory involved in the subroutines which describe stiffness, mass, thermal and enforced deformation loads, and force and stress recovery for the curved pipe element. Incorporation of these subroutines into NASTRAN is discussed. Test problems are proposed. Instructions on use of the new element capability are provided.

  15. Transcriptional burst frequency and burst size are equally modulated across the human genome

    PubMed Central

    Dar, Roy D.; Razooky, Brandon S.; Singh, Abhyudai; Trimeloni, Thomas V.; McCollum, James M.; Cox, Chris D.; Simpson, Michael L.; Weinberger, Leor S.

    2012-01-01

    Gene expression occurs either as an episodic process, characterized by pulsatile bursts, or as a constitutive process, characterized by a Poisson-like accumulation of gene products. It is not clear which mode of gene expression (constitutive versus bursty) predominates across a genome or how transcriptional dynamics are influenced by genomic position and promoter sequence. Here, we use time-lapse fluorescence microscopy to analyze 8,000 individual human genomic loci and find that at virtually all loci, episodic bursting—as opposed to constitutive expression—is the predominant mode of expression. Quantitative analysis of the expression dynamics at these 8,000 loci indicates that both the frequency and size of the transcriptional bursts varies equally across the human genome, independent of promoter sequence. Strikingly, weaker expression loci modulate burst frequency to increase activity, whereas stronger expression loci modulate burst size to increase activity. Transcriptional activators such as trichostatin A (TSA) and tumor necrosis factor α (TNF) only modulate burst size and frequency along a constrained trend line governed by the promoter. In summary, transcriptional bursting dominates across the human genome, both burst frequency and burst size vary by chromosomal location, and transcriptional activators alter burst frequency and burst size, depending on the expression level of the locus. PMID:23064634

  16. The Case of the Disappearing Spindle Burst

    PubMed Central

    Tiriac, Alexandre; Blumberg, Mark S.

    2016-01-01

    Sleep spindles are brief cortical oscillations at 10–15 Hz that occur predominantly during non-REM (quiet) sleep in adult mammals and are thought to contribute to learning and memory. Spindle bursts are phenomenologically similar to sleep spindles, but they occur predominantly in early infancy and are triggered by peripheral sensory activity (e.g., by retinal waves); accordingly, spindle bursts are thought to organize neural networks in the developing brain and establish functional links with the sensory periphery. Whereas the spontaneous retinal waves that trigger spindle bursts in visual cortex are a transient feature of early development, the myoclonic twitches that drive spindle bursts in sensorimotor cortex persist into adulthood. Moreover, twitches—and their associated spindle bursts—occur exclusively during REM (active) sleep. Curiously, despite the persistence of twitching into adulthood, twitch-related spindle bursts have not been reported in adult sensorimotor cortex. This raises the question of whether such spindle burst activity does not occur in adulthood or, alternatively, occurs but has yet to be discovered. If twitch-related spindle bursts do occur in adults, they could contribute to the calibration, maintenance, and repair of sensorimotor systems. PMID:27119028

  17. Spectral evolution of gamma-ray bursts

    NASA Technical Reports Server (NTRS)

    Band, D.; Matteson, J.; Ford, L.; Schaefer, B.; Teegarden, B.; Cline, T.; Paciesas, W.; Pendleton, G.; Fishman, G.; Meegan, C.

    1992-01-01

    BATSE's Spectral Detectors provide a series of high resolution spectra over the duration of a gamma-ray burst; fits to these spectra show the evolution of the continuum as the burst progresses. The burst continuum can usually be fit by the spectral form AE sup alpha exp(-E/kT) from around 25 keV to more than 3 MeV, with varying trends in the value and evolution of the spectral parameters. As a result of limited statistics for E greater than 1 - 2 MeV in the individual spectra, a high energy power law is not required. Only long duration strong bursts can be studied by fitting a series of spectra, and therefore our conclusions concern only this class of burst. The bursts we analyzed tend to be characterized by a hard-to-soft trend both for individual intensity spikes and for the burst as a whole: the hardness leads the count rate in spectra which resolve the temporal variations, while the hardness of successive spikes decreases. We also summarize the performance of the Spectral Detectors and the development of analysis tools to date.

  18. Observational properties of decameter type IV bursts

    NASA Astrophysics Data System (ADS)

    Melnik, Valentin; Brazhenko, Anatoly; Rucker, Helmut; Konovalenko, Alexander; Briand, Carine; Dorovskyy, Vladimir; Zarka, Philippe; Frantzusenko, Anatoly; Panchenko, Michael; Poedts, Stefan; Zaqarashvili, Teimuraz; Shergelashvili, Bidzina

    2013-04-01

    Oscillations of decameter type IV bursts were registered during observations of solar radio emission by UTR-2, URAN-2 and NDA in 2011-2012. Large majority of these bursts were accompanied by coronal mass ejections (CMEs), which were observed by SOHO and STEREO in the visible light. Only in some cases decameter type IV bursts were not associated with CMEs. The largest periods of oscillations P were some tens of minutes. There were some modes of long periods of oscillations simultaneously. Periods of oscillations in flux and in polarization profiles were close. Detailed properties of oscillations at different frequencies were analyzed on the example of two type IV bursts. One of them was observed on April 7, 2011 when a CME happened. Another one (August 1, 2011) was registered without any CME. The 7 April type IV burst had two periods in the frames 75-85 and 35-85 minutes. Interesting feature of these oscillations is decreasing periods with time. The observed decreasing rates dP/dt equaled 0.03-0.07. Concerning type IV burst observed on August 1, 2011 the period of its oscillations increases from 17 min. at 30 MHz to 44 min. at 10 MHz. Connection of type IV burst oscillations with oscillations of magnetic arches and CMEs at corresponding altitudes are discussed. The work is fulfilled in the frame of FP7 project "SOLSPANET".

  19. Development report for dual-burst disks

    SciTech Connect

    Fusco, A.M.

    1996-11-01

    Burst disks, commonly used in pressure relief applications, were studied as single-use valves. A dual-burst disk design was chosen for primary investigation for systems involving separation of gases of two significantly different pressures. The two disks are used to seal either end of a piston cavity that has a different cross-sectional area on each side. Different piston surface areas are used to maintain hydrostatic equilibrium, P{sub 1}A{sub 1} = P{sub 2}A{sub 2}. The single-use valve functions when the downstream pressure is reduced to approximately atmospheric pressure, creating a pressure differential that causes the burst disks to fail. Several parameters were studied to determine the optimum design of the burst disk. These parameters include thickness, diameter, area/pressure ratio, scoring, and disk geometry. The disk material was limited to 304L stainless steel. Factors that were considered essential to the optimization of the design were robustness, manufacturability, and burst pressure variability. The thicknesses of the disks that were studied range from 0.003 in. to 0.010 in. A model for predicting burst pressures of the burst disks was derived. The model combines membrane stress theory with force/displacement data to predict the burst pressure of various designs to within {+-}10%. This model results from studies that characterize the behavior of individual small and large disks. Welding techniques used to join the dual-disk assembly are discussed. Laser welds are used to join and seal the disks to the bulkhead. These welds were optimized for repeatability and robustness. Resistance upset welding is suggested for joining the dual-disk assembly to the pressure vessel body. Resistance upset weld parameters were developed for this particular design so as to minimize the side effects on the burst-disk performance and to provide high-quality welds.

  20. Numerical simulation of burst defects in cold extrusion process

    NASA Astrophysics Data System (ADS)

    Labergère, C.; Lestriez, P.; Saanouni, K.

    2007-05-01

    The formation of the central bursts in axisymmetric cold extrusion is numerically simulated by using 2D finite element analysis (FEA) accounting for the mixed isotropic and kinematic hardening together with the ductile damage effect. The coupling between the ductile damage and the elastoplastic constitutive equations is formulated in the framework of the thermodynamics of irreversible processes together with the Continuum Damage Mechanics (CDM) theory. An isotropic ductile damage model is fully coupled with elastoplastic constitutive equations including non linear isotropic and kinematic hardening. A modified ductile damage criterion based on linear combination of the stress tensor invariants is used in order to predict the occurrence of micro-crack initiation as a discontinuous central bursts along the bar axis. The implicit integration scheme of the fully coupled constitutive equations and the Dynamic Explicit resolution scheme to solve the associated initial and boundary value problem are outlined. Application is made to the prediction of the chevron shaped cracks in cold extrusion of a round bar. The effect of various process parameters, as the diameter reduction ratio, the die semi-angle, the friction coefficient and the material ductility, on the central bursts occurrence are discussed.

  1. TORTORA discovery of Naked-Eye Burst fast optical variability

    NASA Astrophysics Data System (ADS)

    Beskin, Grigory; Karpov, Sergey; Bondar, Sergey; Greco, Giuseppe; Guarnieri, Adriano; Bartolini, Corrado; Piccioni, Adalberto; Molinari, Emilio; Chincarini, Guido

    2008-10-01

    Features characterizing gamma-ray bursts in the different spectral bands may be a clue for the nature of their inner engine. Up to now, only several bursts have been observed in optical band during the gamma activity, and the only one-GRB080319B-was covered from rise till fall with high temporal resolution. Here we discuss these data, acquired with TORTORA fast wide-field monitoring optical camera, as well as results of its analysis. The camera observed the position of Naked-Eye Burst, GRB080318B, before, during and after the trigger. It detected the fast rise of optical emission, which reached the peak of V 5.3 at the eighteenth second, had a complex evolution till T+43s and monotonously faded then. The brightest part of the light curve contains two 15-20 s segments with different fluxes, each having two clearly-seen peaks of 5-8 s duration; all four peaks look quasi-periodic with separation of 9 s. There is no clear evidence of any sub-second variability. However, there are signs of quasi-periodic variability on 1s time scale at around the last peak (T+40 till T+50). The general properties of the optical light curve and its variability time scales look similar to the gamma one, but there is no clear correlation between them. This raises serious problems in interpretation of mechanisms generating such variability.

  2. Fast Radio Bursts and Radio Transients from Black Hole Batteries

    NASA Astrophysics Data System (ADS)

    Mingarelli, Chiara; Levin, Janna; Lazio, Joseph

    2016-03-01

    Most black holes (BHs) will absorb a neutron star (NS) companion fully intact, without tidal disruption, suggesting the pair will remain dark to telescopes. Even without tidal disruption, electromagnetic (EM) luminosity is generated from the battery phase of the binary when the BH interacts with the NS magnetic field. Originally the luminosity was expected in high-energy X-rays or gamma-rays, however we conjecture that some of the battery power is emitted in the radio bandwidth. While the luminosity and timescale are suggestive of fast radio bursts (FRBs), NS-BH coalescence rates are too low to make these a primary FRB source. Instead, we propose the transients form a FRB sub-population, distinguishable by a double peak. The main burst is from the peak luminosity before merger, while the post-merger burst follows from the NS magnetic field migration to the BH, causing a shock. NS-BH pairs are desirable for ground-based gravitational wave (GW) observatories since the pair might not be detected any other way, with EM counterparts augmenting the scientific leverage beyond the GW signal. Valuably, EM signal can break degeneracies in the parameters encoded in the GW as well as probe the NS magnetic field strength, yielding insights into open problems in NS magnetic field decay.

  3. Ultrasonic multi-skip tomography for pipe inspection

    SciTech Connect

    Volker, Arno; Zon, Tim van

    2014-02-18

    The inspection of wall loss corrosion is difficult at pipe supports due to limited accessibility. The recently developed ultrasonic Multi-Skip screening technique is suitable for this problem. The method employs ultrasonic transducers in a pitch-catch geometry positioned on opposite sides of the pipe support. Shear waves are transmitted in the axial direction within the pipe wall, reflecting multiple times between the inner and outer surfaces before reaching the receivers. Along this path, the signals accumulate information on the integral wall thickness (e.g., via variations in travel time). The method is very sensitive in detecting the presence of wall loss, but it is difficult to quantify both the extent and depth of the loss. Multi-skip tomography has been developed to reconstruct the wall thickness profile along the axial direction of the pipe. The method uses model-based full wave field inversion; this consists of a forward model for predicting the measured wave field and an iterative process that compares the predicted and measured wave fields and minimizes the differences with respect to the model parameters (i.e., the wall thickness profile). Experimental results are very encouraging. Various defects (slot and flat bottom hole) are reconstructed using the tomographic inversion. The general shape and width are well recovered. The current sizing accuracy is in the order of 1 mm.

  4. Burst Oscillations: Watching Neutron Stars Spin

    NASA Technical Reports Server (NTRS)

    Strohmayer, Tod

    2010-01-01

    It is now almost 15 years since the first detection of rotationally modulated emission from X-ray bursting neutron stars, "burst oscillations," This phenomenon enables us to see neutron stars spin, as the X-ray burst flux asymmetrically lights up the surface. It has enabled a new way to probe the neutron star spin frequency distribution, as well as to elucidate the multidimensional nature of nuclear burning on neutron stars. I will review our current observational understanding of the phenomenon, with an eye toward highlighting some of the interesting remaining puzzles, of which there is no shortage.

  5. Eddy current technique for predicting burst pressure

    DOEpatents

    Petri, Mark C.; Kupperman, David S.; Morman, James A.; Reifman, Jaques; Wei, Thomas Y. C.

    2003-01-01

    A signal processing technique which correlates eddy current inspection data from a tube having a critical tubing defect with a range of predicted burst pressures for the tube is provided. The method can directly correlate the raw eddy current inspection data representing the critical tubing defect with the range of burst pressures using a regression technique, preferably an artificial neural network. Alternatively, the technique deconvolves the raw eddy current inspection data into a set of undistorted signals, each of which represents a separate defect of the tube. The undistorted defect signal which represents the critical tubing defect is related to a range of burst pressures utilizing a regression technique.

  6. System for Testing Thermal Insulation of Pipes

    NASA Technical Reports Server (NTRS)

    Fesmire, James E.; Augustynowicz, Stanislaw D.; Nagy, Zoltan F.

    2003-01-01

    An apparatus and method have been developed for measuring the rates of leakage of heat into pipes carrying liquids, the purpose of the measurements being to quantify the thermal performance of the insulation system. The apparatus is designed primarily for testing pipes used to carry cryogenic liquids, but can also be used for measuring the thermal performance of other insulated pipes or piping systems. The basic measurement principle is straightforward: The outer surface of the pipe insulation is maintained at a fixed warmer temperature. The interior of the pipe is maintained in a narrow fixed lower-temperature range by means of a regular liquid (e.g., water) that is pumped through the pipe at a known flow rate or a cryogenic liquid (e.g., nitrogen) that is saturated at atmospheric pressure and replenished until steady-state conditions are achieved. In the case of water or another liquid pumped through, the inlet and outlet temperatures are measured and heat-leak power is calculated as the mass flow rate of the liquid multiplied by the specific heat of the liquid multiplied by the inlet-to-outlet temperature rise of the liquid. In the case of liquid nitrogen or another low-temperature boiling liquid, the heat-leak power is calculated as the rate of boil-off multiplied by the latent heat of vaporization of the liquid. Then the thermal-insulation performance of the pipe system can be calculated as a function of the measured heat-leak power, the inner and outer boundary temperatures, and the dimensions of the pipe. The apparatus can test as many as three pipes simultaneously. The pipes can have inner diameters up to .15 cm and outer diameters up to .20 cm. The lengths of the pipes may vary; typical lengths are of the order of 18 m. Two thermal guard boxes . one for each end of the pipe(s) under test . are used to make the inlet and outlet fluid connections to the pipe(s) (see figure). The connections include bellows that accommodate thermal expansion and contraction

  7. Fast Radio Bursts and Radio Transients from Black Hole Batteries

    NASA Astrophysics Data System (ADS)

    Mingarelli, Chiara M. F.; Levin, Janna; Lazio, T. Joseph W.

    2015-12-01

    Most black holes (BHs) will absorb a neutron star (NS) companion fully intact without tidal disruption, suggesting the pair will remain dark to telescopes. Even without tidal disruption, electromagnetic (EM) luminosity is generated from the battery phase of the binary when the BH interacts with the NS magnetic field. Originally, the luminosity was expected to be in high-energy X-rays or gamma-rays, however, we conjecture that some of the battery power is emitted in the radio bandwidth. While the luminosity and timescale are suggestive of fast radio bursts (FRBs; millisecond-scale radio transients) NS-BH coalescence rates are too low to make these a primary FRB source. Instead, we propose that the transients form a FRB sub-population, distinguishable by a double peak with a precursor. The rapid ramp-up in luminosity manifests as a precursor to the burst which is 20%-80% as luminous given 0.5 ms timing resolution. The main burst arises from the peak luminosity before the merger. The post-merger burst follows from the NS magnetic field migration to the BH, causing a shock. NS-BH pairs are especially desirable for ground-based gravitational wave (GW) observatories since the pair might not otherwise be detected, with EM counterparts greatly augmenting the scientific leverage beyond the GW signal. The EM signal’s ability to break degeneracies in the parameters encoded in the GW and probe the NS magnetic field strength is quite valuable, yielding insights into open problems in NS magnetic field decay.

  8. FAST RADIO BURSTS AND RADIO TRANSIENTS FROM BLACK HOLE BATTERIES

    SciTech Connect

    Mingarelli, Chiara M. F.; Levin, Janna; Lazio, T. Joseph W.

    2015-12-01

    Most black holes (BHs) will absorb a neutron star (NS) companion fully intact without tidal disruption, suggesting the pair will remain dark to telescopes. Even without tidal disruption, electromagnetic (EM) luminosity is generated from the battery phase of the binary when the BH interacts with the NS magnetic field. Originally, the luminosity was expected to be in high-energy X-rays or gamma-rays, however, we conjecture that some of the battery power is emitted in the radio bandwidth. While the luminosity and timescale are suggestive of fast radio bursts (FRBs; millisecond-scale radio transients) NS–BH coalescence rates are too low to make these a primary FRB source. Instead, we propose that the transients form a FRB sub-population, distinguishable by a double peak with a precursor. The rapid ramp-up in luminosity manifests as a precursor to the burst which is 20%–80% as luminous given 0.5 ms timing resolution. The main burst arises from the peak luminosity before the merger. The post-merger burst follows from the NS magnetic field migration to the BH, causing a shock. NS–BH pairs are especially desirable for ground-based gravitational wave (GW) observatories since the pair might not otherwise be detected, with EM counterparts greatly augmenting the scientific leverage beyond the GW signal. The EM signal’s ability to break degeneracies in the parameters encoded in the GW and probe the NS magnetic field strength is quite valuable, yielding insights into open problems in NS magnetic field decay.

  9. Suppression of the Near Wall Burst Process of a Fully Developed Turbulent Pipe Flow

    DTIC Science & Technology

    1993-05-01

    tunmel turbulent boundary layer a ) velocity fluctuation skewness levels and b) velocity fluctuation kurtosis levels ...by the undisturbed total uv level and u*. a ) quadrants I and 2 and b) quadrants 3 and 4 ...................... 105 5.20 Spanwise development of the uw...times larger than the long time averaged levels . A knowledge of the mechanisms governing the formation and dynamics of the lift-up of the low speed

  10. A self-adapting approach for the detection of bursts and network bursts in neuronal cultures.

    PubMed

    Pasquale, Valentina; Martinoia, Sergio; Chiappalone, Michela

    2010-08-01

    Dissociated networks of neurons typically exhibit bursting behavior, whose features are strongly influenced by the age of the culture, by chemical/electrical stimulation or by environmental conditions. To help the experimenter in identifying the changes possibly induced by specific protocols, we developed a self-adapting method for detecting both bursts and network bursts from electrophysiological activity recorded by means of micro-electrode arrays. The algorithm is based on the computation of the logarithmic inter-spike interval histogram and automatically detects the best threshold to distinguish between inter- and intra-burst inter-spike intervals for each recording channel of the array. An analogous procedure is followed for the detection of network bursts, looking for sequences of closely spaced single-channel bursts. We tested our algorithm on recordings of spontaneous as well as chemically stimulated activity, comparing its performance to other methods available in the literature.

  11. QUASI-PERIODIC OSCILLATIONS AND BROADBAND VARIABILITY IN SHORT MAGNETAR BURSTS

    SciTech Connect

    Huppenkothen, Daniela; Watts, Anna L.; Uttley, Phil; Van der Horst, Alexander J.; Van der Klis, Michiel; Kouveliotou, Chryssa; Goegues, Ersin; Granot, Jonathan; Vaughan, Simon; Finger, Mark H.

    2013-05-01

    The discovery of quasi-periodic oscillations (QPOs) in magnetar giant flares has opened up prospects for neutron star asteroseismology. However, with only three giant flares ever recorded, and only two with data of sufficient quality to search for QPOs, such analysis is seriously data limited. We set out a procedure for doing QPO searches in the far more numerous, short, less energetic magnetar bursts. The short, transient nature of these bursts requires the implementation of sophisticated statistical techniques to make reliable inferences. Using Bayesian statistics, we model the periodogram as a combination of red noise at low frequencies and white noise at high frequencies, which we show is a conservative approach to the problem. We use empirical models to make inferences about the potential signature of periodic and QPOs at these frequencies. We compare our method with previously used techniques and find that although it is on the whole more conservative, it is also more reliable in ruling out false positives. We illustrate our Bayesian method by applying it to a sample of 27 bursts from the magnetar SGR J0501+4516 observed by the Fermi Gamma-ray Burst Monitor, and we find no evidence for the presence of QPOs in any of the bursts in the unbinned spectra, but do find a candidate detection in the binned spectra of one burst. However, whether this signal is due to a genuine quasi-periodic process, or can be attributed to unmodeled effects in the noise is at this point a matter of interpretation.

  12. Analyzing Space-Based Interferometric Measurements of Stars and Network Measurements of Gamma-Ray Bursts

    NASA Technical Reports Server (NTRS)

    Taff, L. G.

    1998-01-01

    Since the announcement of the discovery of sources of bursts of gamma-ray radiation in 1973, hundreds more reports of such bursts have now been published. Numerous artificial satellites have been equipped with gamma-ray detectors including the very successful Compton Gamma Ray Observatory BATSE instrument. Unfortunately, we have made no progress in identifying the source(s) of this high energy radiation. We suspected that this was a consequence of the method used to define gamma-ray burst source "error boxes." An alternative procedure to compute gamma-ray burst source positions, with a purely physical underpinning, was proposed in 1988 by Taff. Since then we have also made significant progress in understanding the analytical nature of the triangulation problem and in computing actual gamma-ray burst positions and their corresponding error boxes. For the former, we can now mathematically illustrate the crucial role of the area occupied by the detectors, while for the latter, the Atteia et al. (1987) catalog has been completely re-reduced. There are very few discrepancies in locations between our results and those of the customary "time difference of arrival" procedure. Thus, we have numerically demonstrated that the end result, for the positions, of these two very different-looking procedures is the same. Finally, for the first time, we provide a sample of realistic "error boxes" whose non-simple shapes vividly portray the difficulty of burst source localization.

  13. An effective implementation scheme of just-in-time protocol for optical burst switching networks

    NASA Astrophysics Data System (ADS)

    Wu, Guiling; Li, Xinwan; Chen, Jian-Ping; Wang, Hui

    2005-02-01

    Optical burst switching (OBS) has been emerging as a promising technology that can effectively support the next generation IP-oriented transportation networks. JIT signaling protocol for OBS is relatively simple and easy to be implemented by hardware. This paper presented an effective scheme to implement the JIT protocol, which not only can effectively implement reservation and release of optical channels based on JIT, but also can process the failure of channel reservation and release due to loss of burst control packets. The scheme includes: (1) a BHP (burst head packet) path table is designed and built at each OBS node. It is used to guarantee the corresponding burst control packet, i.e. BHP, BEP (burst end packet) and BEP_ACK (BEP acknowledgement), to be transmitted in the same path. (2) The timed retransmission of BEP and the reversed deletion of the item in BHP path tables triggered by the corresponding BEP_ACK are combined to solve the problems caused by the loss of the signaling messages in channel reservation and release process. (3) Burst head packets and BEP_ACK are transmitted using "best-effort" method. Related signaling messages and their formats for the proposed scheme are also given.

  14. Strain Modal Analysis of Small and Light Pipes Using Distributed Fibre Bragg Grating Sensors.

    PubMed

    Huang, Jun; Zhou, Zude; Zhang, Lin; Chen, Juntao; Ji, Chunqian; Pham, Duc Truong

    2016-09-25

    Vibration fatigue failure is a critical problem of hydraulic pipes under severe working conditions. Strain modal testing of small and light pipes is a good option for dynamic characteristic evaluation, structural health monitoring and damage identification. Unique features such as small size, light weight, and high multiplexing capability enable Fibre Bragg Grating (FBG) sensors to measure structural dynamic responses where sensor size and placement are critical. In this paper, experimental strain modal analysis of pipes using distributed FBG sensors ispresented. Strain modal analysis and parameter identification methods are introduced. Experimental strain modal testing and finite element analysis for a cantilever pipe have been carried out. The analysis results indicate that the natural frequencies and strain mode shapes of the tested pipe acquired by FBG sensors are in good agreement with the results obtained by a reference accelerometer and simulation outputs. The strain modal parameters of a hydraulic pipe were obtained by the proposed strain modal testing method. FBG sensors have been shown to be useful in the experimental strain modal analysis of small and light pipes in mechanical, aeronautic and aerospace applications.

  15. Strain Modal Analysis of Small and Light Pipes Using Distributed Fibre Bragg Grating Sensors

    PubMed Central

    Huang, Jun; Zhou, Zude; Zhang, Lin; Chen, Juntao; Ji, Chunqian; Pham, Duc Truong

    2016-01-01

    Vibration fatigue failure is a critical problem of hydraulic pipes under severe working conditions. Strain modal testing of small and light pipes is a good option for dynamic characteristic evaluation, structural health monitoring and damage identification. Unique features such as small size, light weight, and high multiplexing capability enable Fibre Bragg Grating (FBG) sensors to measure structural dynamic responses where sensor size and placement are critical. In this paper, experimental strain modal analysis of pipes using distributed FBG sensors ispresented. Strain modal analysis and parameter identification methods are introduced. Experimental strain modal testing and finite element analysis for a cantilever pipe have been carried out. The analysis results indicate that the natural frequencies and strain mode shapes of the tested pipe acquired by FBG sensors are in good agreement with the results obtained by a reference accelerometer and simulation outputs. The strain modal parameters of a hydraulic pipe were obtained by the proposed strain modal testing method. FBG sensors have been shown to be useful in the experimental strain modal analysis of small and light pipes in mechanical, aeronautic and aerospace applications. PMID:27681728

  16. Simultaneous fog formation and thermophoretic droplet deposition in a turbulent pipe flow

    SciTech Connect

    Epstein, M.; Hauser, G.M. )

    1991-02-01

    Simultaneous aerosol formation by equilibrium condensation and the migration of the resulting droplets to the cold surface by thermophoresis is studied theoretically for a turbulent pipe flow. The problem is one in which a mixture of a vapor and noncondensable gas flows into a section of pipe where the pipe wall is cooled to below the dew point of the vapor. Because the temperature gradient at the pipe wall decays to zero once the gas travels far enough into the pipe, only some fraction of the droplets formed will deposit on the pipe wall. The equations of energy and diffusion suggest that turbulence leads to a discontinuity in the aerosol (fog) concentration at the boundary between the fog and clear regions. Numerical solutions are obtained for CsOH fog formation and deposition in steam flow, a particular case of current practical interest in water reactor safety. The axial and radial variations of the aerosol and vapor concentrations are displayed graphically, as are the location of the fog boundary as a function of axial distance and the efficiency of deposition as a function of the pipe wall temperature.

  17. Gamma-Ray Burst Progenitors

    NASA Astrophysics Data System (ADS)

    Levan, Andrew; Crowther, Paul; de Grijs, Richard; Langer, Norbert; Xu, Dong; Yoon, Sung-Chul

    2016-12-01

    We review our current understanding of the progenitors of both long and short duration gamma-ray bursts (GRBs). Constraints can be derived from multiple directions, and we use three distinct strands; (i) direct observations of GRBs and their host galaxies, (ii) parameters derived from modelling, both via population synthesis and direct numerical simulation and (iii) our understanding of plausible analog progenitor systems observed in the local Universe. From these joint constraints, we describe the likely routes that can drive massive stars to the creation of long GRBs, and our best estimates of the scenarios that can create compact object binaries which will ultimately form short GRBs, as well as the associated rates of both long and short GRBs. We further discuss how different the progenitors may be in the case of black hole engine or millisecond-magnetar models for the production of GRBs, and how central engines may provide a unifying theme between many classes of extremely luminous transient, from luminous and super-luminous supernovae to long and short GRBs.

  18. Gamma-ray burst cosmology

    NASA Astrophysics Data System (ADS)

    Wang, F. Y.; Dai, Z. G.; Liang, E. W.

    2015-08-01

    Gamma-ray bursts (GRBs) are the most luminous electromagnetic explosions in the Universe, which emit up to 8.8 × 1054 erg isotropic equivalent energy in the hard X-ray band. The high luminosity makes them detectable out to the largest distances yet explored in the Universe. GRBs, as bright beacons in the deep Universe, would be the ideal tool to probe the properties of high-redshift universe: including the cosmic expansion and dark energy, star formation rate, the reionization epoch and the metal enrichment history of the Universe. In this article, we review the luminosity correlations of GRBs, and implications for constraining the cosmological parameters and dark energy. Observations show that the progenitors of long GRBs are massive stars. So it is expected that long GRBs are tracers of star formation rate. We also review the high-redshift star formation rate derived from GRBs, and implications for the cosmic reionization history. The afterglows of GRBs generally have broken power-law spectra, so it is possible to extract intergalactic medium (IGM) absorption features. We also present the capability of high-redshift GRBs to probe the pre-galactic metal enrichment and the first stars.

  19. Overview Animation of Gamma-ray Burst

    NASA Video Gallery

    Gamma-ray bursts are the most luminous explosions in the cosmos. Astronomers think most occur when the core of a massive star runs out of nuclear fuel, collapses under its own weight, and forms a b...

  20. POPULATION SYNTHESIS AND GAMMA RAY BURST PROGENITORS

    SciTech Connect

    C. L. FREYER

    2000-12-11

    Population synthesis studies of binaries are always limited by a myriad of uncertainties from the poorly understood effects of binary mass transfer and common envelope evolution to the many uncertainties that still remain in stellar evolution. But the importance of these uncertainties depends both upon the objects being studied and the questions asked about these objects. Here I review the most critical uncertainties in the population synthesis of gamma-ray burst progenitors. With a better understanding of these uncertainties, binary population synthesis can become a powerful tool in understanding, and constraining, gamma-ray burst models. In turn, as gamma-ray bursts become more important as cosmological probes, binary population synthesis of gamma-ray burst progenitors becomes an important tool in cosmology.

  1. Expected Performance of the GLAST Burst Monitor

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

    The GLAST Burst Monitor (GBM) will enhance LAT observations of GRBs by extending the spectral coverage from the LAT threshold down to approx. 8 kev, and will provide a trigger for re-orienting the spacecraft to observe delayed emission from selected bursts outside the LAT field of view. GBM consists of twelve NaI scintillation detectors operating in the 8 kev to 1 MeV energy range and two BGO scintillation detectors operating in the 150 keV to 30 MeV energy range. Detector resolution, effective area, and angular response have been determined by calibrations. Analyses indicate that the on-board burst threshold will be approx. 0.7 photon/cm2/s and the on-board burst localization accuracy will typically be better than 8 degrees.

  2. Impulsive solar X-ray bursts

    NASA Technical Reports Server (NTRS)

    Crannell, C. J.; Frost, K. J.; Maetzler, C.; Ohki, K.; Saba, J. L.

    1977-01-01

    A set of 22 simple, impulsive solar flares, identified in the OSO-5 hard X-ray data, were analyzed together with coincident microwave and meterwave radio observations. The rise times and fall times of the X-ray bursts are found to be highly correlated and effectively equal, strongly suggesting a flare energizing mechanism that is reversible. The good time resolution available for these observations reveals that the microwave emission is influenced by an additional process, evident in the tendency of the microwave emission to peak later and decay more slowly than the symmetric X-ray bursts. Meterwave emission is observed in coincidence with the 5 events which show the strongest time correlation between the X-ray and microwave burst structure. This meterwave emission is characterized by U-burst radiation, indicating confinement of the flare source.

  3. The Gamma-Ray Burst Next Door

    NASA Technical Reports Server (NTRS)

    Wanjek, Christopher

    2003-01-01

    I hesitate to spawn a thousand bad sci-fi flicks, but here it goes: Scientists now say that some gamma-ray bursts, the most powerful explosions in the universe, originate in nearby galaxy clusters. If one were to occur nearby, it could wipe out life on Earth. Fortunately, the chances of mass extinction are slimmer than the Chicago Cubs meeting the Boston Red Sox in the World Series (. . . and the Red Sox winning). But a new analysis of over 1400 archived gamma-ray bursts reveals that about 100 bursts originated within 325 million light-years of Earth, and not billions of light-years away as previously thought. If so, there's no reason why a burst couldn't go off in our galaxy.

  4. NASA's Swift Sees 'Dual Personality' Burst

    NASA Video Gallery

    These animations illustrate two wildly different explanations for GRB 101225A, better known as the "Christmas burst." First, a solitary neutron star in our own galaxy shreds and accretes an approac...

  5. CMEs and frequency cutoff of solar bursts

    NASA Astrophysics Data System (ADS)

    Stanislavsky, Al.; Konovalenko, Al.; Koval, Ar.; Volvach, Y.; Zarka, P.

    2016-05-01

    Radio observations of solar bursts with high-frequency cutoff by the radio telescope UTR-2 (near Kharkiv, Ukraine) at 8-33 MHz on 17-19 August 2012 are presented. Such cutoff may be attributed to the emergence of the burst sources behind limb of the Sun with respect to an observer on the Earth. The events are strongly associated with solar eruptions occurred in a new active region. Ray tracing simulations show that the CMEs play a constructive role for the behind-limb bursts to be detected in ground-based observations. Likely, due to tunnel-like cavities with low density in CMEs, the radio emission of behind-limb solar bursts can be directed towards the Earth.

  6. GLAST Burst Monitor Trigger Classification Algorithm

    NASA Technical Reports Server (NTRS)

    Perrin, D. J.; Sidman, E. D.; Meegan, C. A.; Briggs, M. S.; Connaughton, V.

    2004-01-01

    The Gamma Ray Large Area Space Telescope (GLAST), currently set for launch in the first quarter of 2007, will consist of two instruments, the GLAST Burst Monitor (GBM) and the Large Area Telescope (LAT). One of the goals of the GBM is to identify and locate gamma-ray bursts using on-board software. The GLAST observatory can then be re-oriented to allow observations by the LAT. A Bayesian analysis will be used to distinguish gamma-ray bursts from other triggering events, such as solar flares, magnetospheric particle precipitation, soft gamma repeaters (SGRs), and Cygnus X-1 flaring. The trigger parameters used in the analysis are the burst celestial coordinates, angle from the Earth's horizon, spectral hardness, and the spacecraft geomagnetic latitude. The algorithm will be described and the results of testing will be presented.

  7. Transverse Bursts in Inclined Layer Convection: Experiment

    NASA Astrophysics Data System (ADS)

    Daniels, Karen; Wiener, Richard; Bodenschatz, Eberhard

    2002-03-01

    We report experimental results on inclined layer convection in a fluid of Prandtl number σ ≈ 1. A codimension-two point divides regions of buoyancy-driven convection (longitudinal rolls) at lower angles from shear-driven convection (transverse rolls) at higher angles (Daniels et al. PRL 84: 5320, 2000). In the region of buoyancy-driven convection, near the codimension-two point, we observe longitudinal rolls with intermittent, localized, subharmonic transverse bursts. The patterns are spatiotemporally chaotic. With increasing temperature difference the bursts increase in duration and number. We examine the details of the bursting process (e.g. the energy of longitudinal, transverse, and mixed modes) and compare our results to bursting processes in other systems. This work is supported by the National Science Foundation under grant DMR-0072077 and the IGERT program in nonlinear systems, grant DGE-9870631.

  8. Dual manifold heat pipe evaporator

    DOEpatents

    Adkins, D.R.; Rawlinson, K.S.

    1994-01-04

    An improved evaporator section is described for a dual manifold heat pipe. Both the upper and lower manifolds can have surfaces exposed to the heat source which evaporate the working fluid. The tubes in the tube bank between the manifolds have openings in their lower extensions into the lower manifold to provide for the transport of evaporated working fluid from the lower manifold into the tubes and from there on into the upper manifold and on to the condenser portion of the heat pipe. A wick structure lining the inner walls of the evaporator tubes extends into both the upper and lower manifolds. At least some of the tubes also have overflow tubes contained within them to carry condensed working fluid from the upper manifold to pass to the lower without spilling down the inside walls of the tubes. 1 figure.

  9. Dual manifold heat pipe evaporator

    DOEpatents

    Adkins, Douglas R.; Rawlinson, K. Scott

    1994-01-01

    An improved evaporator section for a dual manifold heat pipe. Both the upper and lower manifolds can have surfaces exposed to the heat source which evaporate the working fluid. The tubes in the tube bank between the manifolds have openings in their lower extensions into the lower manifold to provide for the transport of evaporated working fluid from the lower manifold into the tubes and from there on into the upper manifold and on to the condenser portion of the heat pipe. A wick structure lining the inner walls of the evaporator tubes extends into both the upper and lower manifolds. At least some of the tubes also have overflow tubes contained within them to carry condensed working fluid from the upper manifold to pass to the lower without spilling down the inside walls of the tubes.

  10. Variable-Conductance Heat Pipes

    NASA Technical Reports Server (NTRS)

    Antoniuk, D.

    1986-01-01

    In response to need to accurately and efficiently predict performance of variable-conductance heat pipes (VCHP's) incorporated in spacecraft thermalcontrol systems, computer code VCHPDA developed to interact with thermal analyzer programs such as SINDA (Systems Improved Numerical Differencing Analyzer). Calculates length of gas-blocked region and vapor temperature in active portion. Advantages of VCHPDA over prior programs improved accuracy, unconditional stability, and increased efficiency of solution resulting from novel approach and use of state-of-the-art numerical techniques for solving VCHP mathematical model. Code valuable tool in design and evaluation of advanced thermal-control systems using variable-conductance heat pipes. Written in FORTRAN IV for use on CDC 600 computers.

  11. A Non-Triggered Burst Supplement to the BATSE Gamma-Ray Burst Catalogs

    NASA Technical Reports Server (NTRS)

    Kommers, J.; Lewin, W. H.; Kouveliotou, C.; vanParadijs, J.; Pendleton, G. N.; Meegan, C. A.; Fishman, G. J.

    1998-01-01

    The Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory detects gamma-ray bursts (GRBs) with a real-time burst detection (or "trigger") system running onboard the spacecraft. Under some circumstances, however, a GRB may not activate the onboard burst trigger. For example, the burst may be too faint to exceed the onboard detection threshold, or it may occur while the onboard burst trigger is disabled for technical reasons. This paper is a catalog of such "non-triggered" GRBs that were detected in a search of the archival continuous data from BATSE. It lists 873 non-triggered bursts that were recorded between 1991 December 9.0 and 1997 December 17.0. For each burst, the catalog gives an estimated source direction, duration, peak flux, and fluence. Similar data are presented for 50 additional bursts of unknown origin that were detected in the 25-50 keV range; these events may represent the low-energy "tail" of the GRB spectral distribution. This catalog increases the number of GRBs detected with BATSE by 48% during the time period covered by the search.

  12. QoS-guaranteed burst transmission for VoIP service over optical burst switching networks

    NASA Astrophysics Data System (ADS)

    Tachibana, Takuji; Kasahara, Shoji

    2007-08-01

    We propose a burst transmission method that guarantees the voice over Internet protocol (VoIP) service. The proposed method consists of three techniques: round-robin burst assembly with slotted scheduling, priority control with void filling, and hop-based preemption. Each technique is utilized so that the burst loss probability and the burst transmission delay satisfy VoIP quality of service (QoS). We evaluate by simulation the performance of the proposed method in NSFNET with 14 nodes. Numerical examples show that our proposed method is effective for guaranteeing the VoIP QoS while accommodating a large number of VoIP users.

  13. Inspecting an ethylene pipe line

    SciTech Connect

    Ramsvig, D.M. ); Duncan, J.; Zillinger, L. )

    1991-07-01

    This paper reports on the Alberta Gas Ethylene Co. (AGEC), completion of intensive internal cleaning and inspection program on their 112-mi ethylene pipe line. AGEC operates two ethylene manufacturing facilities in central Alberta, Canada. The ethylene plants are located 12.4 mi east of Red Deer, Alta., at Joffre, and supply two customers in Joffre. The remaining ethylene is shipped by the 112-mi, 12-in. line to a storage cavern near Edmonton.

  14. Entrainment in electrohydrodynamic heat pipes

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

    A theoretical analysis for predicting the onset of the Kelvin-Helmholtz instability is reported. The model for the analysis is described, and the derived stability criterion are given. It is concluded that surface tension plays a role in the entrainment limit of electro hydrodynamic heat pipes. The surface of the liquid in an EHD flow structure is open, with no restriction placed on the wavenumbers of perturbations.

  15. Progress Report: Pressure Vessel Burst Test Study

    DTIC Science & Technology

    1994-08-01

    report is provided on a program developed to study through test and analysis, the characteristics of blast waves and fragmentation generated by ruptured ...vessels were composite overwrapped pressure vessels ( COPV ) and were cut with a shaped charge (no groove) around its center. The burst location on the...and the shaped charge cut area (shown with dotted lines). BURST INITIATION Longitudinal stress in the circumferential grooves (for developing axial

  16. Localizing the Fast Radio Burst 121102

    NASA Astrophysics Data System (ADS)

    Chatterjee, Shami; Wharton, Robert; Law, Casey J.; Hessels, Jason; Burke-Spolaor, Sarah; Bower, Geoffrey C.; Abruzzo, Matthew W.; Bassa, Cees; Butler, Bryan J.; Cordes, James M.; Paul, Demorest; Kaspi, Victoria M.; McLaughlin, Maura; Ransom, Scott M.; Scholz, Paul; Seymour, Andrew; Spitler, Laura; Tendulkar, Shriharsh P.; PALFA Survey Team; VLA+AO FRB121102 Simultaneous Campaign Team; EVN FRB121102 Campaign Team

    2017-01-01

    The precise localization of a fast radio burst and the identification of its host counterpart would allow constraints on their distances and energetics, and enable us to discriminate between various origin scenarios, from the local and mundane to the cosmological and exotic. Here we report on the results of an ongoing localization campaign on the repeating fast radio burst source, FRB 121102, with the VLA, Arecibo, and other telescopes.

  17. Gamma-Ray Burst Class Properties

    NASA Technical Reports Server (NTRS)

    Hakkila, Jon; Haglin, David J.; Pendleton, Geoffrey N.; Mallozzi, Robert S.; Meegan, Charles A.; Roiger, Richard J.

    2000-01-01

    Guided by the supervised pattern recognition algorithm C4.5 developed by Quinlan in 1986, we examine the three gamma-ray burst classes identified by Mukherjee et al. in 1998. C4.5 provides strong statistical support for this classification. However, with C4.5 and our knowledge of the Burst and Transient Source Experiment (BATSE) instrument, we demonstrate that class 3 (intermediate fluence, intermediate duration, soft) does not have to be a distinct source population: statistical/systematic errors in measuring burst attributes combined with the well-known hardness/intensity correlation can cause low peak flux class 1 (high fluence, long, intermediate hardness) bursts to take on class 3 characteristics naturally. Based on our hypothesis that the third class is not a distinct one, we provide rules so that future events can be placed in either class 1 or class 2 (low fluence, short, hard). We find that the two classes are relatively distinct on the basis of Band's work in 1993 on spectral parameters alpha, beta, and E (sub peak) alone. Although this does not indicate a better basis for classification, it does suggest that different physical conditions exist for class 1 and class 2 bursts. In the process of studying burst class characteristics, we identify a new bias affecting burst fluence and duration measurements. Using a simple model of how burst duration can be underestimated, we show how this fluence duration bias can affect BATSE measurements and demonstrate the type of effect it can have on the BATSE fluence versus peak flux diagram.

  18. Variable Protostellar Accretion with Episodic Bursts

    NASA Astrophysics Data System (ADS)

    Vorobyov, Eduard I.; Basu, Shantanu

    2015-06-01

    We present the latest development of the disk gravitational instability and fragmentation model, originally introduced by us to explain episodic accretion bursts in the early stages of star formation. Using our numerical hydrodynamics model with improved disk thermal balance and star-disk interaction, we computed the evolution of protostellar disks formed from the gravitational collapse of prestellar cores. In agreement with our previous studies, we find that cores of higher initial mass and angular momentum produce disks that are more favorable to gravitational instability and fragmentation, while a higher background irradiation and magnetic fields moderate the disk tendency to fragment. The protostellar accretion in our models is time-variable, thanks to the nonlinear interaction between different spiral modes in the gravitationally unstable disk, and can undergo episodic bursts when fragments migrate onto the star owing to the gravitational interaction with other fragments or spiral arms. Most bursts occur in the partly embedded Class I phase, with a smaller fraction taking place in the deeply embedded Class 0 phase and a few possible bursts in the optically visible Class II phase. The average burst duration and mean luminosity are found to be in good agreement with those inferred from observations of FUors. The model predicts the existence of two types of bursts: the isolated ones, showing well-defined luminosity peaks separated with prolonged periods (˜ {{10}4} yr) of quiescent accretion, and clustered ones, demonstrating several bursts occurring one after another during just a few hundred years. Finally, we estimate that 40%-70% of the star-forming cores can display bursts after forming a star-disk system.

  19. Search for absorption edges in superexpansion bursts

    NASA Astrophysics Data System (ADS)

    in't Zand, Jean

    2013-09-01

    Our goal is to measure with the LETGS a series of bright type-I X-ray bursts with strong photospheric radius expansion ('superexpansion') to search for absorption edges due to the ashes of nuclear burning. We request a quick TOO, to be triggered by ISS-MAXI and Swift-BAT, with a total exposure time of 100 ks to obtain the detection of about 10 bursts.

  20. GAMCIT: A gamma ray burst detector

    NASA Technical Reports Server (NTRS)

    Surka, Derek M.; Grunsfeld, John M.; Warneke, Brett A.

    1992-01-01

    The origin of celestial gamma ray bursts remains one of the great mysteries of modern astrophysics. The GAMCIT Get-Away-Special payload is designed to provide new and unique data in the search for the sources of gamma ray bursts. GAMCIT consists of three gamma ray detectors, an optical CCD camera, and an intelligent electronics system. This paper describes the major components of the system, including the electronics and structural designs.

  1. Supernovae and gamma-ray bursts connection

    SciTech Connect

    Valle, Massimo Della

    2015-12-17

    I’ll review the status of the Supernova/Gamma-Ray Burst connection. Several pieces of evidence suggest that long duration Gamma-ray Bursts are associated with bright SNe-Ic. However recent works suggest that GRBs might be produced in tight binary systems composed of a massive carbon-oxygen cores and a neutron star companion. Current estimates of the SN and GRB rates yield a ratio GRB/SNe-Ibc in the range ∼ 0.4% − 3%.

  2. Establishing the existence of lines in gamma-ray bursts

    NASA Technical Reports Server (NTRS)

    Loredo, T. J.; Lamb, D. Q.

    1992-01-01

    A rigorous method for establishing the existence of lines in gamma-ray bursts is described which is based on Bayesian inference. In particular, it is shown how the problem of line detection can be reduced to that of comparing two models, a model consisting only of a continuum spectrum and a model with an additional feature in it. The simple case of a Gaussian line is considered, and it is noted that the results can be readily extended to the case of time-dependent lines.

  3. Further observations of the burst source MXB 1728-34

    NASA Technical Reports Server (NTRS)

    Hoffman, J. A.; Lewin, W. H. G.; Doty, J.

    1977-01-01

    MXB 1728-34 has been observed by the SAS 3 observatory on eight occasions. It was bursting 95-100 per cent of the time, with burst intervals from 4 to 8 hr. The burst intervals were not correlated with the burst intensities. Seven relatively hard bursts occurring in July 1976 were all observed at energies up to about 30 keV. Following each of these bursts, enhanced X-ray emission was observed for several minutes, with a much softer spectrum than that of the bursts themselves. No periodic pulsations were observed from the associated steady source.

  4. Hot Leg Piping Materials Issues

    SciTech Connect

    V. Munne

    2006-07-19

    With Naval Reactors (NR) approval of the Naval Reactors Prime Contractor Team (NRPCT) recommendation to develop a gas cooled reactor directly coupled to a Brayton power conversion system as the space nuclear power plant (SNPP) for Project Prometheus (References a and b) the reactor outlet piping was recognized to require a design that utilizes internal insulation (Reference c). The initial pipe design suggested ceramic fiber blanket as the insulation material based on requirements associated with service temperature capability within the expected range, very low thermal conductivity, and low density. Nevertheless, it was not considered to be well suited for internal insulation use because its very high surface area and proclivity for holding adsorbed gases, especially water, would make outgassing a source of contaminant gases in the He-Xe working fluid. Additionally, ceramic fiber blanket insulating materials become very friable after relatively short service periods at working temperatures and small pieces of fiber could be dislodged and contaminate the system. Consequently, alternative insulation materials were sought that would have comparable thermal properties and density but superior structural integrity and greatly reduced outgassing. This letter provides technical information regarding insulation and materials issues for the Hot Leg Piping preconceptual design developed for the Project Prometheus space nuclear power plant (SNPP).

  5. Physics of Gamma Ray Burst Sources

    NASA Technical Reports Server (NTRS)

    Meszaros, Peter

    2004-01-01

    During this grant period, the physics of gamma-ray bursts was investigated. A number of new results have emerged. The importance of pair formation in high compactness burst spectra may help explain x-ray flashes; a universal jet shape is a likely explanation for the distribution of jet break times; gravitational waves may be copiously produced both in short bursts from compact mergers and in long bursts arising from collapsars; x-ray iron lines are likely to be due to interaction with the stellar atmosphere of the progenitor; prompt optical flashes from reverse shocks will give diagnostics on the Lorentz factor and the environment; GeV and TeV emission from bursts may be expected in the external shock; etc. The group working with the PI included postdocs Dr. Bing Zhang (now assistant professor at University of Nevada); Dr. Shiho Kobayashi; graduate student Lijun Gou; collaborators Drs. Tim Kallman and Martin Rees. Meszaros shared with Rees and Dr. Bohan Paczynsky the AAS Rossi Prize in 2000 for their work on the theory of gamma ray bursts. The refereed publications and conference proceedings resulting from this research are summarized below. The PI gave a number of invited talks at major conferences, also listed.

  6. Voyager observations of Jovian millisecond radio bursts

    NASA Technical Reports Server (NTRS)

    Alexander, J. K.; Desch, M. D.

    1984-01-01

    Voyager Planetary Radio Astronomy data collected over 30-day intervals centered on the two close encounters with Jupiter were utilized to study the characteristics of millisecond-duration radio bursts (s-bursts) at frequencies between 5 and 15 MHz. In this frequency range, s-bursts are found to occur almost independently of Central Meridian Longitude and to depend entirely on the phase of Io with respect to the observer's planetocentric line of sight. Individual bursts typically cover a total frequency range of about 1.5 to 3 MHz, and they are usually strongly circularly polarized. Most bursts in a particular s-burst storm will exhibit the same polarization sense (either right-hand or left-hand), and there is some evidence for a systematic pattern in which one polarizations sense is preferred over the other as a function of Io phase and Central Meridian Longitude. These data are all suggestive of a radio source that is located along the instantaneous Io flux tube and that extends over a linear dimension of 5000 km along the field lines in both the northern and southern Hemispheres.

  7. Terahertz inline wall thickness monitoring system for plastic pipe extrusion

    SciTech Connect

    Hauck, J. E-mail: d.stich@skz.de E-mail: m.bastian@skz.de Stich, D. E-mail: d.stich@skz.de E-mail: m.bastian@skz.de Heidemeyer, P. E-mail: d.stich@skz.de E-mail: m.bastian@skz.de Bastian, M. E-mail: d.stich@skz.de E-mail: m.bastian@skz.de Hochrein, T. E-mail: d.stich@skz.de E-mail: m.bastian@skz.de

    2014-05-15

    Conventional and commercially available inline wall thickness monitoring systems for pipe extrusion are usually based on ultrasonic or x-ray technology. Disadvantages of ultrasonic systems are the usual need of water as a coupling media and the high damping in thick walled or foamed pipes. For x-ray systems special safety requirements have to be taken into account because of the ionizing radiation. The terahertz (THz) technology offers a novel approach to solve these problems. THz waves have many properties which are suitable for the non-destructive testing of plastics. The absorption of electrical isolators is typically very low and the radiation is non-ionizing in comparison to x-rays. Through the electromagnetic origin of the THz waves they can be used for contact free measurements. Foams show a much lower absorption in contrast to acoustic waves. The developed system uses THz pulses which are generated by stimulating photoconductive switches with femtosecond laser pulses. The time of flight of THz pulses can be determined with a resolution in the magnitude of several ten femtoseconds. Hence the thickness of an object like plastic pipes can be determined with a high accuracy by measuring the time delay between two reflections on materials interfaces e.g. at the pipe's inner and outer surface, similar to the ultrasonic technique. Knowing the refractive index of the sample the absolute layer thickness from the transit time difference can be calculated easily. This method in principle also allows the measurement of multilayer systems and the characterization of foamed pipes.

  8. Terahertz inline wall thickness monitoring system for plastic pipe extrusion

    NASA Astrophysics Data System (ADS)

    Hauck, J.; Stich, D.; Heidemeyer, P.; Bastian, M.; Hochrein, T.

    2014-05-01

    Conventional and commercially available inline wall thickness monitoring systems for pipe extrusion are usually based on ultrasonic or x-ray technology. Disadvantages of ultrasonic systems are the usual need of water as a coupling media and the high damping in thick walled or foamed pipes. For x-ray systems special safety requirements have to be taken into account because of the ionizing radiation. The terahertz (THz) technology offers a novel approach to solve these problems. THz waves have many properties which are suitable for the non-destructive testing of plastics. The absorption of electrical isolators is typically very low and the radiation is non-ionizing in comparison to x-rays. Through the electromagnetic origin of the THz waves they can be used for contact free measurements. Foams show a much lower absorption in contrast to acoustic waves. The developed system uses THz pulses which are generated by stimulating photoconductive switches with femtosecond laser pulses. The time of flight of THz pulses can be determined with a resolution in the magnitude of several ten femtoseconds. Hence the thickness of an object like plastic pipes can be determined with a high accuracy by measuring the time delay between two reflections on materials interfaces e.g. at the pipe's inner and outer surface, similar to the ultrasonic technique. Knowing the refractive index of the sample the absolute layer thickness from the transit time difference can be calculated easily. This method in principle also allows the measurement of multilayer systems and the characterization of foamed pipes.

  9. Heat Pipe Solar Receiver Development Activities at Sandia National Laboratories

    SciTech Connect

    Adkins, D.R.; Andraka, C.E.; Moreno, J.B.; Moss, T.A.; Rawlinson, K.S.; Showalter, S.K.

    1999-01-08

    Over the past decade, Sandia National Laboratories has been involved in the development of receivers to transfer energy from the focus of a parabolic dish concentrator to the heater tubes of a Stirling engine. Through the isothermal evaporation and condensation of sodium. a heat-pipe receiver can efficiently transfer energy to an engine's working fluid and compensate for irregularities in the flux distribution that is delivered by the concentrator. The operation of the heat pipe is completely passive because the liquid sodium is distributed over the solar-heated surface by capillary pumping provided by a wick structure. Tests have shown that using a heat pipe can boost the system performance by twenty percent when compared to directly illuminating the engine heater tubes. Designing heat pipe solar receivers has presented several challenges. The relatively large area ({approximately}0.2 m{sup 2}) of the receiver surface makes it difficult to design a wick that can continuously provide liquid sodium to all regions of the heated surface. Selecting a wick structure with smaller pores will improve capillary pumping capabilities of the wick, but the small pores will restrict the flow of liquid and generate high pressure drops. Selecting a wick that is comprised of very tine filaments can increase the permeability of the wick and thereby reduce flow losses, however, the fine wick structure is more susceptible to corrosion and mechanical damage. This paper provides a comprehensive review of the issues encountered in the design of heat pipe solar receivers and solutions to problems that have arisen. Topics include: flow characterization in the receiver, the design of wick systems. the minimization of corrosion and dissolution of metals in sodium systems. and the prevention of mechanical failure in high porosity wick structures.

  10. 46 CFR 154.310 - Cargo piping systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo piping systems. 154.310 Section 154.310 Shipping... Arrangements § 154.310 Cargo piping systems. Cargo liquid or vapor piping must: (a) Be separated from other piping systems, except where an interconnection to inert gas or purge piping is required by §...

  11. INTERIOR VIEW WITH LARGE PIPE CASTING MACHINE CASTING A 48' ...

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

    INTERIOR VIEW WITH LARGE PIPE CASTING MACHINE CASTING A 48' PIPE OPERATOR SPRAYING A POWDER TO HELP SOLIDIFY THE PIPE BEING CENTRIFUGALLY CAST. - United States Pipe & Foundry Company Plant, Pipe Casting & Testing Area, 2023 St. Louis Avenue at I-20/59, Bessemer, Jefferson County, AL

  12. 46 CFR 154.522 - Materials for piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Materials for piping. 154.522 Section 154.522 Shipping... Process Piping Systems § 154.522 Materials for piping. (a) The materials for piping systems must meet § 154.625 for the minimum design temperature of the piping, except the material for open ended...

  13. Lightweight Heat Pipes Made from Magnesium

    NASA Technical Reports Server (NTRS)

    Rosenfeld, John N.; Zarembo, Sergei N.; Eastman, G. Yale

    2010-01-01

    Magnesium has shown promise as a lighter-weight alternative to the aluminum alloys now used to make the main structural components of axially grooved heat pipes that contain ammonia as the working fluid. Magnesium heat-pipe structures can be fabricated by conventional processes that include extrusion, machining, welding, and bending. The thermal performances of magnesium heat pipes are the same as those of equal-sized aluminum heat pipes. However, by virtue of the lower mass density of magnesium, the magnesium heat pipes weigh 35 percent less. Conceived for use aboard spacecraft, magnesium heat pipes could also be attractive as heat-transfer devices in terrestrial applications in which minimization of weight is sought: examples include radio-communication equipment and laptop computers.

  14. Extended Development of Variable Conductance Heat Pipes

    NASA Technical Reports Server (NTRS)

    Antoniuk, D.; Edwards, D. K.; Luedke, E. E.

    1978-01-01

    A high-capacity vapor-modulated heat pipe was designed and tested. In 1977, a program was undertaken to use the aforementioned heat pipe to study protection from freezing-point failure, increase control sensitivity, and transient behavior under a wide range of operating conditions in order to determine the full performance potential of the heat pipe. A new concept, based on the vapor-induced-dry-out principle, was developed for passive feedback temperature control as a heat pipe diode. This report documents this work and describes: (1) the experimental and theoretical investigation of the performance of the vapor-modulated heat pipe; and (2) the design, fabrication and test of the heat pipe diode.

  15. Piping inspection carriage having axially displaceable sensor

    DOEpatents

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

    1994-12-06

    A pipe inspection instrument carriage is described for use with a pipe crawler 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 a Y-arm mounted distally thereon for axially aligning the inspection instrumentation and a mounting block, a linear actuator and axial movement arm for extending the inspection instruments radially outward to operably position the inspection instruments on the piping interior. Also, the carriage has a rotation motor and gear assembly 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. 4 figures.

  16. Piping inspection carriage having axially displaceable sensor

    DOEpatents

    Zollinger, William T.; Treanor, Richard C.

    1994-01-01

    A pipe inspection instrument carriage for use with a pipe crawler 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 a y-arm mounted distally thereon for axially aligning the inspection instrumentation and a mounting block, a linear actuator and axial movement arm for extending the inspection instruments radially outward to operably position the inspection instruments on the piping interior. Also, the carriage has a rotation motor and gear assembly 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.

  17. Pipe lifting hook having clamp assembly

    SciTech Connect

    Codner, J.A.

    1984-06-12

    A pipe lifting hook is provided having a generally ''C'' shaped hook member having an elongated lower portion being insertable within the end of a joint of pipe and having an upper portion positionable above the pipe and provided with lifting connection means. The hook member is frictionally clamped to the pipe by grip shoe means that is movably supported by the upper portion of the hook member and is selectably movable from a released position out of contact with said pipe to a locked position in frictional locking engagement with the outer surface of the pipe. A ratchet mechanism couples said grip shoe means to the upper portion of the hook member and is manually positionable to lock said grip shoe means at said locked position or release said grip shoe means for movement toward said released position thereof.

  18. 46 CFR 154.503 - Piping and piping system components: Protection from movement.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... cause stresses that exceed the design stresses, the piping and piping system components and cargo tanks... including: (1) Bellows; (2) Slip joints; (3) Ball joints; or (e) Other means specially approved by...

  19. Pipe Cleaning Operating Procedures

    SciTech Connect

    Clark, D.; Wu, J.; /Fermilab

    1991-01-24

    This cleaning procedure outlines the steps involved in cleaning the high purity argon lines associated with the DO calorimeters. The procedure is broken down into 7 cycles: system setup, initial flush, wash, first rinse, second rinse, final rinse and drying. The system setup involves preparing the pump cart, line to be cleaned, distilled water, and interconnecting hoses and fittings. The initial flush is an off-line flush of the pump cart and its plumbing in order to preclude contaminating the line. The wash cycle circulates the detergent solution (Micro) at 180 degrees Fahrenheit through the line to be cleaned. The first rinse is then intended to rid the line of the majority of detergent and only needs to run for 30 minutes and at ambient temperature. The second rinse (if necessary) should eliminate the remaining soap residue. The final rinse is then intended to be a check that there is no remaining soap or other foreign particles in the line, particularly metal 'chips.' The final rinse should be run at 180 degrees Fahrenheit for at least 90 minutes. The filters should be changed after each cycle, paying particular attention to the wash cycle and the final rinse cycle return filters. These filters, which should be bagged and labeled, prove that the pipeline is clean. Only distilled water should be used for all cycles, especially rinsing. The level in the tank need not be excessive, merely enough to cover the heater float switch. The final rinse, however, may require a full 50 gallons. Note that most of the details of the procedure are included in the initial flush description. This section should be referred to if problems arise in the wash or rinse cycles.

  20. Development of a heat pipe heat dissipation method for CPV application

    NASA Astrophysics Data System (ADS)

    Moon, Seok-Hwan; Lee, Kyu-Ho; Hong, Soo-Hyun; Ko, Sang-Choon; Jun, Chi-Hoon; Mun, Jae-Kyoung; Park, Ki-Sung; Park, Jun-Hee

    2014-09-01

    Even when there is a sufficient heat dissipation area from the heat sink to the environment, if the heat flux in the chip package substrate cannot be transferred rapidly to the heat sink, a thermal problem may occur.[1] In this study, a relatively thin CPV module compared to general models was considered. Because four solar chips are mounted on a center column in the CPV module, heat can accumulate rapidly. Therefore, a heat pipe with high thermal conductivity was considered as the heat dissipation method.[2] The heat pipe adopted in the present study is commercially available and has a circular type sintered wick in it. To apply the heat pipe to the CPV module with thin thickness and a central column with 4 solar cells, it should be pressed and bent. The thermal characteristics of the pressed and bent heat pipe was investigated experimentally.

  1. Flight data analysis and further development of variable-conductance heat pipes. [for aircraft control

    NASA Technical Reports Server (NTRS)

    Enginer, J. E.; Luedke, E. E.; Wanous, D. J.

    1976-01-01

    Continuing efforts in large gains in heat-pipe performance are reported. It was found that gas-controlled variable-conductance heat pipes can perform reliably for long periods in space and effectively provide temperature stabilization for spacecraft electronics. A solution was formulated that allows the control gas to vent through arterial heat-pipe walls, thus eliminating the problem of arterial failure under load, due to trace impurities of noncondensable gas trapped in an arterial bubble during priming. This solution functions well in zero gravity. Another solution was found that allows priming at a much lower fluid charge. A heat pipe with high capacity, with close temperature control of the heat source and independent of large variations in sink temperature was fabricated.

  2. Bending loss of terahertz pipe waveguides.

    PubMed

    Lu, Jen-Tang; Hsueh, Yu-Chun; Huang, Yu-Ru; Hwang, Yuh-Jing; Sun, Chi-Kuang

    2010-12-06

    We present an experimental study on the bending loss of terahertz (THz) pipe waveguide. Bending loss of pipe waveguides is investigated for various frequencies, polarizations, core diameters, cladding thicknesses, and cladding materials. Our results indicate that the pipe waveguides with lower guiding loss suffer lower bending loss due to stronger mode confinement. The unexpected low bending loss in the investigated simple leaky waveguide structure promises variety of flexible applications.

  3. Transverse flat plate heat pipe experiment

    NASA Technical Reports Server (NTRS)

    Edelstein, F.

    1978-01-01

    This paper describes a Shuttle-launched flight experiment to evaluate the performance of a transverse flat plate heat pipe that serves as an integral temperature control/mounting panel for electronic equipment. A transverse heat pipe is a gas-controlled variable conductance heat pipe that can handle relatively large thermal loads. An experiment designed to flight test the concept over a 6-9 month period is self-sufficient with respect to electrical power, timing sequences, and data storage.

  4. Alkali Metal Heat Pipe Life Issues

    SciTech Connect

    Reid, Robert S.

    2004-07-01

    One approach to fission power system design uses alkali metal heat pipes for the core primary heat-transfer system. Heat pipes may also be used as radiator elements or auxiliary thermal control elements. This synopsis characterizes long-life core heat pipes. References are included where information that is more detailed can be found. Specifics shown here are for demonstration purposes and do not necessarily reflect current Nasa Project Prometheus point designs. (author)

  5. Simulated Heat-Pipe Vapor Dynamics

    DTIC Science & Technology

    1987-05-01

    129 - viii - Notation A pipe area A porous pipe property (Eq 2.12) AR aspect ratio (Eq 6.27) B porous pipe property (Eq 2.12) C coefficient of...laminar flow, in circular porous tubes. He assumed a constant -5- - -t- -- - - - -- 5-- - - ’C -W property fluid and uniform wall mass transfer. He...two gas models studied by Levy. They found that assuming thermodynamic equilibrium of the two phase flow was valid -9- when compared with unpublished

  6. Downhole pipe selection for acoustic telemetry

    DOEpatents

    Drumheller, D.S.

    1995-12-19

    A system is described for transmitting signals along a downhole string including a plurality of serially connected tubular pipes such as drill or production pipes, a transmitter for transmitting a signal along the string and a receiver for receiving the signal placed along the string at a location spaced from said transmitting means, wherein the pipes between the transmitter and the receiver are ordered according to length of tube to minimize loss of signal from said transmitter to said receiver. 7 figs.

  7. Downhole pipe selection for acoustic telemetry

    DOEpatents

    Drumheller, Douglas S.

    1995-01-01

    A system for transmitting signals along a downhole string including a plurality of serially connected tubular pipes such as drill or production pipes, a transmitter for transmitting a signal along the string and a receiver for receiving the signal placed along the string at a location spaced from said transmitting means, wherein the pipes between the transmitter and the receiver are ordered according to length of tube to minimize loss of signal from said transmitter to said receiver.

  8. Modeling gamma-ray bursts

    NASA Astrophysics Data System (ADS)

    Maxham, Amanda

    Discovered serendipitously in the late 1960s, gamma-ray bursts (GRBs) are huge explosions of energy that happen at cosmological distances. They provide a grand physical playground to those who study them, from relativistic effects such as beaming, jets, shocks and blastwaves to radiation mechanisms such as synchrotron radiation to galatic and stellar populations and history. Through the Swift and Fermi space telescopes dedicated to observing GRBs over a wide range of energies (from keV to GeV), combined with accurate pinpointing that allows ground based follow-up observations in the optical, infrared and radio, a rich tapestry of GRB observations has emerged. The general picture is of a mysterious central engine (CE) probably composed of a black hole or neutron star that ejects relativistic shells of matter into intense magnetic fields. These shells collide and combine, releasing energy in "internal shocks" accounting for the prompt emission and flaring we see and the "external shock" or plowing of the first blastwave into the ambient surrounding medium has well-explained the afterglow radiation. We have developed a shell model code to address the question of how X-ray flares are produced within the framework of the internal shock model. The shell model creates randomized GRB explosions from a central engine with multiple shells and follows those shells as they collide, merge and spread, producing prompt emission and X-ray flares. We have also included a blastwave model, which can constrain X-ray flares and explain the origin of high energy (GeV) emission seen by the Fermi telescope. Evidence suggests that gamma-ray prompt emission and X-ray flares share a common origin and that at least some flares can only be explained by long-lasting central engine activity. We pay special attention to the time history of central engine activity, internal shocks, and observed flares. We calculate the gamma-ray (Swift/BAT band) and X-ray (Swift/XRT band) lightcurves for arbitrary

  9. Modeling of transient heat pipe operation

    NASA Technical Reports Server (NTRS)

    Colwell, G. T.; Hartley, J. G.

    1985-01-01

    The overall goal is to gain a better understanding of the transient behavior of heat pipes operating under both normal and adverse conditions. Normal operation refers to cases where the capillary structure remains fully wetted. Adverse operation occurs when drying, re-wetting, choking, noncontinuum flow, freezing, thawing etc., occur within the heat pipe. The work was redirected towards developing the capability to predict operational behavior of liquid metal heat pipes used for cooling aerodynamic structures. Of particular interest is the startup of such heat pipes from an initially frozen state such as might occur during re-entry of a space vehicle into the Earth's atmosphere or during flight of hypersonic aircraft.

  10. Development of an in pipe inspection minirobot

    NASA Astrophysics Data System (ADS)

    Tătar, M. O.; Pop, A.

    2016-08-01

    In the first part of the paper, authors present a new in pipe inspection minirobot with wheeled adaptable structure for pipe diameters ranging from 220 to 380 mm. The mechanical structure is composed of three adaptable mechanisms placed at 120 degrees around the central axes. For adapting to the interior surface of the pipe, a passive method is used which utilizes elastic elements. In the second part of the paper, authors present the simulation of in pipe minirobot locomotion, components of driving and control systems, user interface, conclusions and future development areas.

  11. Note: Ultrasonic liquid flow meter for small pipes.

    PubMed

    Yu, Yang; Zong, Guanghua

    2012-02-01

    An ultrasonic flow meter for small pipes is presented. For metal pipe diameter smaller than 10 mm, clamp-on ultrasonic contrapropagation flow meters may encounter difficulties if cross talk or the short acoustic path contributes to large uncertainty in transit time measurement. Axial inline flow meters can avoid these problems, but they may introduce other problems if the transducer port is not properly positioned. Three types of pipe connecting tees are compared using the computational fluid dynamics (CFD) method. CFD shows the 45° tee has more uniform velocity distribution over the measuring section. A prototype flow meter using the 45° tee was designed and tested. The zero flow experiment shows the flow meter has a maximum of 0.002 m∕s shift over 24 h. The flow meter is calibrated by only 1 meter factor. After calibration, inaccuracy lower than 0.1% of reading was achieved in the laboratory, for a measuring range from 15 to 150 g∕s (0.29 to 2.99 m∕s; Re = 2688 to 26,876).

  12. Location of Agricultural Drainage Pipes and Assessment of Agricultural Drainage Pipe Conditions Using Ground Penetrating Radar

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methods are needed to not only locate buried agricultural drainage pipe, but to also determine if the pipes are functioning properly with respect to water delivery. The primary focus of this research project was to confirm the ability of ground penetrating radar (GPR) to locate buried drainage pipe ...

  13. Method and apparatus for coherent burst ranging

    DOEpatents

    Wachter, Eric A.; Fisher, Walter G.

    1998-01-01

    A high resolution ranging method is described utilizing a novel modulated waveform, hereafter referred to as coherent burst modulation. In the coherent burst method, high frequency modulation of an acoustic or electromagnetic transmitter, such as a laser, is performed at a modulation frequency. This modulation frequency is transmitted quasi-continuously in the form of interrupted bursts of radiation. Energy from the transmitter is directed onto a target, interacts with the target, and the returning energy is collected. The encoded burst pattern contained in the collected return signal is detected coherently by a receiver that is tuned so as to be principally sensitive to the modulation frequency. The receiver signal is processed to determine target range using both time-of-flight of the burst envelope and phase shift of the high frequency modulation. This approach effectively decouples the maximum unambiguous range and range resolution relationship of earlier methods, thereby allowing high precision ranging to be conducted at arbitrarily long distances using at least one burst of encoded energy. The use of a receiver tuned to the high frequency modulation contained within the coherent burst vastly improves both sensitivity in the detection of the target return signal and rejection of background interferences, such as ambient acoustic or electromagnetic noise. Simultaneous transmission at several energies (or wavelengths) is possible by encoding each energy with a separate modulation frequency or pattern; electronic demodulation at the receiver allows the return pattern for each energy to be monitored independently. Radial velocity of a target can also be determined by monitoring change in phase shift of the return signal as a function of time.

  14. Method and apparatus for coherent burst ranging

    DOEpatents

    Wachter, E.A.; Fisher, W.G.

    1998-04-28

    A high resolution ranging method is described utilizing a novel modulated waveform, hereafter referred to as coherent burst modulation. In the coherent burst method, high frequency modulation of an acoustic or electromagnetic transmitter, such as a laser, is performed at a modulation frequency. This modulation frequency is transmitted quasi-continuously in the form of interrupted bursts of radiation. Energy from the transmitter is directed onto a target, interacts with the target, and the returning energy is collected. The encoded burst pattern contained in the collected return signal is detected coherently by a receiver that is tuned so as to be principally sensitive to the modulation frequency. The receiver signal is processed to determine target range using both time-of-flight of the burst envelope and phase shift of the high frequency modulation. This approach effectively decouples the maximum unambiguous range and range resolution relationship of earlier methods, thereby allowing high precision ranging to be conducted at arbitrarily long distances using at least one burst of encoded energy. The use of a receiver tuned to the high frequency modulation contained within the coherent burst vastly improves both sensitivity in the detection of the target return signal and rejection of background interferences, such as ambient acoustic or electromagnetic noise. Simultaneous transmission at several energies (or wavelengths) is possible by encoding each energy with a separate modulation frequency or pattern; electronic demodulation at the receiver allows the return pattern for each energy to be monitored independently. Radial velocity of a target can also be determined by monitoring change in phase shift of the return signal as a function of time. 12 figs.

  15. A biomechanical study on burst mechanisms of plant fruit: stress analysis of pericarps before bursting.

    PubMed

    Endo, Yasuhiro; Sakamoto, Jiro; Kashiwano, Yuki; Yokota, Hideo; Nakamura, Sakiko; Kinoshita, Eichiro

    2010-10-01

    Bursting of fruit is a very interesting biomechanical phenomenon because its mechanism is directly related to the plant's reproduction. A plant that produces fruit that bursts powerfully and spreads the seeds widely has the advantage of reproduction without relying on other mechanisms such as transportation of fruit by insects. The structures of many types of fruit have likely been optimized by evolution, although the structure itself appears rather simplistic. Strain energy is stored in each pericarp because of growth deformation, swelling or desiccation just before bursting. Throughout these changes, the mechanical stress of the pericarps is at equilibrium. At the instant of bursting, the stored strain energy is released very rapidly. Quick and wide motion of the pericarps in a certain direction is advantageous for throwing the seed a long distance. The motion and deformation of bursting pericarps depend on their tissue structure and mechanical stress condition just before the burst. We tracked the bursting motion by using a high-speed camera. Then we calculated the pre-burst stress generated in a pericarp of Impatiens by using the finite-element method. The boundary condition obtained by experiments using a high-speed video camera is given, and the stress was calculated using reverse deformation analysis. The stress distribution of the pericarp is effective in causing the pericarp motion to throw the seeds far away.

  16. A Nontriggered Burst Supplement to the BATSE Gamma-Ray Burst Catalogs

    NASA Technical Reports Server (NTRS)

    Kommers, Jefferson M.; Lewin, Walter H. G.; Kouveliotou, Chryssa; vanParadijs, Jan; Pendleton, Geoffrey N.; Meegan, Charles A.; Fishman, Gerald J.

    2001-01-01

    The Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory detects gamma-ray bursts (GRBs) with a real-time burst detection (or "trigger") system running onboard the spacecraft. Under some circumstances, however, a GRB may not activate the on-board burst trigger. For example, the burst may be too faint to exceed the on-board detection threshold, or it may occur while the on-board burst trigger is disabled for technical reasons. This paper describes a catalog of 873 "nontriggered" GRBs that were detected in a search of the archival continuous data from BATSE recorded between 1991 December 9.0 and 1997 December 17.0. For each burst, the catalog gives an estimated source direction, duration, peak flux, and fluence. Similar data are presented for 50 additional bursts of unknown origin that were detected in the 25-50 keV range; these events may represent the low-energy "tail" of the GRB spectral distribution. This catalog increases the number of GRBs detected with BATSE by 48% during the time period covered by the search.

  17. Internal cathodic protection of cement-lined steel pipes

    SciTech Connect

    Jensen, F.O. ); Tems, R.D. )

    1988-07-01

    Internally coated, cement-lined, carbon steel pipes have been used extensively for ballast- and service-water systems offshore. Mechanical cracking of the lining, undercutting, and erosion have resulted in corrosion and system leaks. Cathodic protection is one alternative that has been evaluated as a solution. Cathodic protection normally gives limited protection when applied internally to a pipeline system. Tests have been performed to evaluate this hypothesis and the possibility of improved current distribution due to the cement lining. This paper presents the test results as well as a solution to the problem. Internally coated, cement-lined steel pipes are used for ballast-water, service-water, and fire-water systems in the offshore oil and gas production industry.

  18. NON-DESTRUCTIVE TESTING METHODS FOR GEOTHERMAL PIPING.

    SciTech Connect

    BERNDT,M.L.

    2001-03-23

    Non-destructive testing is a key component of optimized plant inspection and maintenance programs. Risk based inspection, condition based maintenance and reliability centered maintenance systems all require detection, location and sizing of defects or flaws by non-destructive methods. Internal damage of geothermal piping by corrosion and erosion-corrosion is an ongoing problem requiring inspection and subsequent maintenance decisions to ensure safe and reliable performance. Conventional manual ultrasonic testing to determine remaining wall thickness has major limitations, particularly when damage is of a random and localized nature. Therefore, it is necessary to explore alternative non-destructive methods that offer potential benefits in terms of accurate quantification of size, shape and location of damage, probability of detection, ability to use on-line over long ranges, and economics. A review of non-destructive methods and their applicability to geothermal piping was performed. Based on this, ongoing research will concentrate on long range guided wave and dynamic methods.

  19. Testing Thermal Properties of the Cooling Device with Heat Pipes

    NASA Astrophysics Data System (ADS)

    Nemec, P.; Čaja, A.; Malcho, M.

    2013-04-01

    Paper deal about testing of device with heat pipes and about research alternative possible applications of heat pipes and potential improvements in purpose effective heat sink from power switches of device. This device is used in various static and moveable applications. Testing device is part of control unit in rail vehicle. The amount of heat produced by power switches depend from working conditions of static converter. Great impact on heat sink has, how as season also this if the vehicle is moving or don't moving. If the vehicle is moving the heat transfer form energy converter to surrounding is caused by forced convection of air flow around device. But the critical conditions occur if the vehicle doesn't move, because the application of this cooling device is based on natural convection. The study deal solution of the problem heat transfer from energy converter to surrounding by natural convection.

  20. Steady hydrodynamic loads due to vortex shedding from the OTEC cold water pipe. Final report

    SciTech Connect

    Griffin, O.M.

    1982-01-13

    This report is limited in scope to consideration of the problems caused by vortex shedding from flexible, bluff cylinders in steady current flows, as these problems apply to the OTEC cold water pipe. In particular, the steady deflections caused by the amplified drag forces that accompany vortex-excited oscillations are considered. Emphasis placed upon the discussion of design methods, applications of these methods to practical problems, and comparison with available experimental data. A discussion is given of laboratory and field studies that have been conducted with model OTEC cold water pipes. Various devices that have been developed for the suppression of vortex-excited oscillations also are discussed. A comparison is made of the effectiveness of various suppresion devices and procedures, and practical approaches to implementing their application are presented. The implications of vortex-induced hydrodynamic drag and the suppression of vortex-excited oscillations in OTEC cold water pipe design are discussed briefly.