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Sample records for leake enric plaza

  1. Learning by Televised "Plaza Sesamo" in Mexico

    ERIC Educational Resources Information Center

    Diaz-Guerrero, Rogelio; Holtzman, Wayne H.

    1974-01-01

    Tests were administered pre, during, and post telecast of Plaza Sesamo to children in lower class day-care centers in Mexico City. Results indicate significant differences between control and experimental groups in general knowledge, numbers, letters, and words as taught by Plaza Sesamo. (Author/BJG)

  2. Historic Landscape Plan University of Florida Campus, Plaza of ...

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

    Historic Landscape Plan - University of Florida Campus, Plaza of the Americas, University of Florida Campus Quad Bounded by West University Avenue, US 441/Southwest 13th Street, Stadium Road, and North-South Drive, Gainesville, Alachua County, FL

  3. University of Florida Campus, Plaza of the Americas, University of ...

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

    University of Florida Campus, Plaza of the Americas, University of Florida Campus Quad Bounded by West University Avenue, US 441/Southwest 13th Street, Stadium Road, and North-South Drive, Gainesville, Alachua County, FL

  4. President Kennedy in Dallas: Dealey Plaza memorialized

    NASA Astrophysics Data System (ADS)

    Asmus, John F.

    2007-07-01

    The assassination of US President John F. Kennedy on November 22, 1963 transformed the US political landscape as well as the trajectory of subsequent world history. The venue of that tragic event in Dallas was Dealey Plaza, encompassing the "grassy knoll" and the adjacent book-depository and courthouse buildings. For the past forty years the site has undergone a series of conservation/preservation projects in order to make it more suitable for those visiting either in homage or out of curiosity. One such project concerned the deterioration of ironwork within the "Old Red Courthouse". The building architect noted that both stairway railings and floor-support trusses were corroding and deteriorating at accelerating rates. In most situations of this sort the iron would be sandblasted and repainted. However, in this instance sandblasting was inappropriate due to environmental concerns and logistical limitations. Furthermore, historical authenticity criteria dictated that the metal be preserved with its original unpainted finish. In order to avoid excessive floor loading (in this fragile old building) and the generation significant environmental air pollution (within urban Dallas) the general contractor (Avery Mays, Inc.) opted to evaluate photonic divestment. Both laser cleaning and laser glazing were assessed for efficacy and cost effectiveness. Xenon-flashlamp irradiation was evaluated both with and without citric acid augmentation. Citric acid matrix-assisted flashlamp treatment was selected for the preservation of the courthouse ironwork. This decision was based on three advantages over laser treatments: higher speed and cost effectiveness, preservation of the historic "Oliver Foundry" logo markings, and the chemical passivation and rust resistance of the final surface patina.

  5. Chlorofluorocarbon leak detection technology

    SciTech Connect

    Munday, E.B.

    1990-12-01

    There are about 590 large coolant systems located at the Portsmouth Gaseous Diffusion Plant (PORTS) and the Paducah Gaseous Diffusion Plant (PGDP) leaking nearly 800,000 lb of R-114 refrigerant annually (1989 estimate). A program is now under way to reduce the leakage to 325,000 lb/year -- an average loss of 551 lb/year (0.063 lb/h) per coolant system, some of which are as large as 800 ft. This report investigates leak detection technologies that can be used to locate leaks in the coolant systems. Included are descriptions, minimum leak detection rate levels, advantages, disadvantages, and vendor information on the following technologies: bubbling solutions; colorimetric leak testing; dyes; halogen leak detectors (coronea discharge detectors; halide torch detectors, and heated anode detectors); laser imaging; mass spectroscopy; organic vapor analyzers; odorants; pressure decay methods; solid-state electrolytic-cell gas sensors; thermal conductivity leak detectors; and ultrasonic leak detectors.

  6. Sealing Nitrogen Tetroxide Leaks

    NASA Technical Reports Server (NTRS)

    Garrard, George G.; Houston, Donald W.; Scott, Frank D.

    1990-01-01

    Use of Furmanite FSC-N-6B sealant in clam-shell sealing device makes it possible to stop leaks of nitrogen tetroxide through defective or improperly-seated plumbing fittings. Devised to stop leaks in vent line of small rocket motor on Space Shuttle. Also used on plumbing containing hydrazine and other hazardous fluids, and repair withstands severe temperature, vibration, and shock. Leaks stopped in place, without draining or replacement of leaking parts.

  7. Measuring Small Leak Holes

    NASA Technical Reports Server (NTRS)

    Koch, D. E.; Stephenson, J. G.

    1983-01-01

    Hole sizes deduced from pressure measurements. Measuring apparatus consists of pitot tube attached to water-filled manometer. Compartment tested is pressurized with air. Pitot probe placed at known distance from leak. Dynamic pressure of jet measured at that point and static pressure measured in compartment. Useful in situations in which small leaks are tolerable but large leaks are not.

  8. Leak detector uses ultrasonics

    NASA Technical Reports Server (NTRS)

    Heisman, R. M.; Iceland, W. F.; Keir, A. R.

    1978-01-01

    Probe located on outer wall of vacuum-jacketed fluid lines detects leaks on inner wall. Probe picks up and amplifies vibrations that occur when gas rushes through leak and converts them to audible signal or CRT display. System is considerably simpler to use than helium leak detectors and allows rapid checks to be made as part of routine maintenance.

  9. View from west porch looking southwest across plaza towards castro/breen ...

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

    View from west porch looking south-west across plaza towards castro/breen adobe and plaza hotel (duplicate of CA-1501-13) - Zanetta House, San Juan Bautista State Historical Park, San Juan Bautista, San Benito County, CA

  10. View looking northwest, showing Flagpole, Memorial Plaza around Flagpole, and ...

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

    View looking northwest, showing Flagpole, Memorial Plaza around Flagpole, and the south wall and portico of the central wing of Building No. 1 - U.S. Veterans Hospital, Jefferson Barracks, Flagpole, VA Medical Center, Jefferson Barracks Division 1 Jefferson Barracks Drive, Saint Louis, Independent City, MO

  11. Leak detection/verification

    SciTech Connect

    Krhounek, V.; Zdarek, J.; Pecinka, L.

    1997-04-01

    Loss of coolant accident (LOCA) experiments performed as part of a Leak Before Break (LBB) analysis are very briefly summarized. The aim of these experiments was to postulate the leak rates of the coolant. Through-wall cracks were introduced into pipes by fatigue cycling and hydraulically loaded in a test device. Measurements included coolant pressure and temperature, quantity of leaked coolant, displacement of a specimen, and acoustic emission. Small cracks were plugged with particles in the coolant during testing. It is believed that plugging will have no effect in cracks with leak rates above 35 liters per minute. The leak rate safety margin of 10 is sufficient for cracks in which the leak rate is more than 5 liters per minute.

  12. Permanent underwater leak detector

    NASA Astrophysics Data System (ADS)

    Costello, L.; McStay, D.; Moodie, D.; Kane, D.

    2009-07-01

    A new optoelectronic sensor for the real time monitoring of key components such as valves and connectors within the subsea production equipment for leaks of hydraulic fluid is reported. The sensor is capable of detecting low concentrations of such fluids, allowing the early detection of small leaks, and the ability to monitor the evolution of the leak-rate with time, hence providing an important new tool in complying with environmental requirements, enabling early intervention and optimising subsea production

  13. Detecting Methane Leaks

    NASA Technical Reports Server (NTRS)

    Grant, W. B.; Hinkley, E. D.

    1984-01-01

    Remote sensor uses laser radiation backscattered from natural targets. He/Ne Laser System for remote scanning of Methane leaks employs topographic target to scatter light to receiver near laser transmitter. Apparatus powered by 1.5kW generator transported to field sites and pointed at suspected methane leaks. Used for remote detection of natural-gas leaks and locating methane emissions in landfill sites.

  14. Apparatus for detecting leaks

    DOEpatents

    Booth, Eugene T.

    1976-02-24

    A method and apparatus for determining the position of and estimating the size of leaks in an evacuating apparatus comprising the use of a testing gas such as helium or hydrogen flowing around said apparatus whereby the testing gas will be drawn in at the site of any leaks.

  15. pico-PLAZA, a genome database of microbial photosynthetic eukaryotes.

    PubMed

    Vandepoele, Klaas; Van Bel, Michiel; Richard, Guilhem; Van Landeghem, Sofie; Verhelst, Bram; Moreau, Hervé; Van de Peer, Yves; Grimsley, Nigel; Piganeau, Gwenael

    2013-08-01

    With the advent of next generation genome sequencing, the number of sequenced algal genomes and transcriptomes is rapidly growing. Although a few genome portals exist to browse individual genome sequences, exploring complete genome information from multiple species for the analysis of user-defined sequences or gene lists remains a major challenge. pico-PLAZA is a web-based resource (http://bioinformatics.psb.ugent.be/pico-plaza/) for algal genomics that combines different data types with intuitive tools to explore genomic diversity, perform integrative evolutionary sequence analysis and study gene functions. Apart from homologous gene families, multiple sequence alignments, phylogenetic trees, Gene Ontology, InterPro and text-mining functional annotations, different interactive viewers are available to study genome organization using gene collinearity and synteny information. Different search functions, documentation pages, export functions and an extensive glossary are available to guide non-expert scientists. To illustrate the versatility of the platform, different case studies are presented demonstrating how pico-PLAZA can be used to functionally characterize large-scale EST/RNA-Seq data sets and to perform environmental genomics. Functional enrichments analysis of 16 Phaeodactylum tricornutum transcriptome libraries offers a molecular view on diatom adaptation to different environments of ecological relevance. Furthermore, we show how complementary genomic data sources can easily be combined to identify marker genes to study the diversity and distribution of algal species, for example in metagenomes, or to quantify intraspecific diversity from environmental strains.

  16. Leak checking in ISABELLE

    SciTech Connect

    Briggs, J.; Halama, H.J.

    1981-01-01

    The Intersecting Storage Accelerator (ISABELLE) contains two completely independent vacuum systems. One known as Beam Vacuum operates at 1 x 10/sup -11/ Torr and maintains a very clean environment for the circulating proton beam. The other system known as Insulating Vacuum maintains superconducting magnet vessels at a pressure below 1 x 10/sup -6/ Torr. In this system all gasses except helium are cryocondensed on the cold surfaces of superconducting magnets and cryogenic circuits. Turbomolecular pumps pump the inadvertent small helium leaks. The helium background both in the MagCOOL area and in the ISABELLE tunnel limits the sensitivity of conventional leak detectors. Leak detection in ISABELLE is one of the most important functions, since there are thousands of bellows and welds operating at 4 K and at 15 atmosphere pressure and that many welds can only be leak checked at room temperature. Leak rates are known to increase by 4 orders of magnitude when cooled from 300 K to 4 K. Thus the required 10/sup -10/ Torr liters s/sup -1/ sensitivity is essential for proper operation and methods and equipment which permit the location of such leaks in large systems have been developed and tested on the First Cell and the refrigerators. They produced a completely leak free system, i.e. the helium background did not change when all pumps were closed for 24 hours. These methods and the equipment are discussed in detail.

  17. Automated leak test systems

    SciTech Connect

    Cordaro, J.V.; Thompson, W.D.; Reeves, G.

    1997-09-15

    An automated leak test system for tritium shipping containers has been developed at Westinghouse Savannah River Co. (WSRC). The leak detection system employs a computer controlled helium detector which allows an operator to enter key information when prompted. The software for controlling the tests and the equipment apparatus were both designed and manufactured at the Savannah River Technology Center within WSRC. Recertification Test: Every twelve months, the pressure vessel portion of the shipping container itself must undergo a rigorous recertification leak test. After an empty pressure vessel (shipping container) is assembled, it is placed into one of six stainless steel belljars for helium leak testing. The belljars are fashioned in row much the same as assembly line arrangement. Post-load Test: A post-load leak test is performed upon reservoirs that have been filled with tritium and placed inside the shipping containers mentioned above. These leak tests are performed by a rate-of-rise method where the area around the shipping container seals is evacuated, valved off from the vacuum pump, and then the vacuum pressure is monitored over a two-minute period. The Post Load Leak Test is a quality verification test to ensure that the shipping container has been correctly assembled. 2 figs.

  18. Leak detection aid

    DOEpatents

    Steeper, T.J.

    1989-12-26

    A leak detection apparatus and method for detecting leaks across an O-ring sealing a flanged surface to a mating surface is an improvement in a flanged surface comprising a shallow groove following O-ring in communication with an entrance and exit port intersecting the shallow groove for injecting and withdrawing, respectively, a leak detection fluid, such as helium. A small quantity of helium injected into the entrance port will flow to the shallow groove, past the O-ring and to the exit port. 2 figs.

  19. Leak detection aid

    DOEpatents

    Steeper, Timothy J.

    1989-01-01

    A leak detection apparatus and method for detecting leaks across an O-ring sealing a flanged surface to a mating surface is an improvement in a flanged surface comprising a shallow groove following O-ring in communication with an entrance and exit port intersecting the shallow groove for injecting and withdrawing, respectively, a leak detection fluid, such as helium. A small quantity of helium injected into the entrance port will flow to the shallow groove, past the O-ring and to the exit port.

  20. Gaseous leak detector

    DOEpatents

    Juravic, Jr., Frank E.

    1988-01-01

    In a short path length mass-spectrometer type of helium leak detector wherein the helium trace gas is ionized, accelerated and deflected onto a particle counter, an arrangement is provided for converting the detector to neon leak detection. The magnetic field of the deflection system is lowered so as to bring the non linear fringe area of the magnetic field across the ion path, thereby increasing the amount of deflection of the heavier neon ions.

  1. Improved gaseous leak detector

    DOEpatents

    Juravic, F.E. Jr.

    1983-10-06

    In a short path length mass-spectrometer type of helium leak detector wherein the helium trace gas is ionized, accelerated and deflected onto a particle counter, an arrangement is provided for converting the detector to neon leak detection. The magnetic field of the deflection system is lowered so as to bring the nonlinear fringe area of the magnetic field across the ion path, thereby increasing the amount of deflection of the heavier neon ions.

  2. Ammonia Leak Locator Study

    NASA Technical Reports Server (NTRS)

    Dodge, Franklin T.; Wuest, Martin P.; Deffenbaugh, Danny M.

    1995-01-01

    The thermal control system of International Space Station Alpha will use liquid ammonia as the heat exchange fluid. It is expected that small leaks (of the order perhaps of one pound of ammonia per day) may develop in the lines transporting the ammonia to the various facilities as well as in the heat exchange equipment. Such leaks must be detected and located before the supply of ammonia becomes critically low. For that reason, NASA-JSC has a program underway to evaluate instruments that can detect and locate ultra-small concentrations of ammonia in a high vacuum environment. To be useful, the instrument must be portable and small enough that an astronaut can easily handle it during extravehicular activity. An additional complication in the design of the instrument is that the environment immediately surrounding ISSA will contain small concentrations of many other gases from venting of onboard experiments as well as from other kinds of leaks. These other vapors include water, cabin air, CO2, CO, argon, N2, and ethylene glycol. Altogether, this local environment might have a pressure of the order of 10(exp -7) to 10(exp -6) torr. Southwest Research Institute (SwRI) was contracted by NASA-JSC to provide support to NASA-JSC and its prime contractors in evaluating ammonia-location instruments and to make a preliminary trade study of the advantages and limitations of potential instruments. The present effort builds upon an earlier SwRI study to evaluate ammonia leak detection instruments [Jolly and Deffenbaugh]. The objectives of the present effort include: (1) Estimate the characteristics of representative ammonia leaks; (2) Evaluate the baseline instrument in the light of the estimated ammonia leak characteristics; (3) Propose alternative instrument concepts; and (4) Conduct a trade study of the proposed alternative concepts and recommend promising instruments. The baseline leak-location instrument selected by NASA-JSC was an ion gauge.

  3. Glycol leak detection system

    NASA Astrophysics Data System (ADS)

    Rabe, Paul; Browne, Keith; Brink, Janus; Coetzee, Christiaan J.

    2016-07-01

    MonoEthylene glycol coolant is used extensively on the Southern African Large Telescope to cool components inside the telescope chamber. To prevent coolant leaks from causing serious damage to electronics and optics, a Glycol Leak Detection System was designed to automatically shut off valves in affected areas. After two years of research and development the use of leaf wetness sensors proved to work best and is currently operational. These sensors are placed at various critical points within the instrument payload that would trigger the leak detector controller, which closes the valves, and alerts the building management system. In this paper we describe the research of an initial concept and the final accepted implementation and the test results thereof.

  4. SEALING SIMULATED LEAKS

    SciTech Connect

    Michael A. Romano

    2004-09-01

    This report details the testing equipment, procedures and results performed under Task 7.2 Sealing Simulated Leaks. In terms of our ability to seal leaks identified in the technical topical report, Analysis of Current Field Data, we were 100% successful. In regards to maintaining seal integrity after pigging operations we achieved varying degrees of success. Internal Corrosion defects proved to be the most resistant to the effects of pigging while External Corrosion proved to be the least resistant. Overall, with limitations, pressure activated sealant technology would be a viable option under the right circumstances.

  5. Sensitive hydrogen leak detector

    DOEpatents

    Myneni, Ganapati Rao

    1999-01-01

    A sensitive hydrogen leak detector system using passivation of a stainless steel vacuum chamber for low hydrogen outgassing, a high compression ratio vacuum system, a getter operating at 77.5 K and a residual gas analyzer as a quantitative hydrogen sensor.

  6. Sensitive hydrogen leak detector

    DOEpatents

    Myneni, G.R.

    1999-08-03

    A sensitive hydrogen leak detector system is described which uses passivation of a stainless steel vacuum chamber for low hydrogen outgassing, a high compression ratio vacuum system, a getter operating at 77.5 K and a residual gas analyzer as a quantitative hydrogen sensor. 1 fig.

  7. The Leaking-Toilet Challenge

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2008-01-01

    Leaking toilets can cost homeowners big dollars--often before it is even realized. Homeowners do not necessarily hear it leaking. It just does, and when the water bill comes due, it can be a most unpleasant surprise. This article presents a classroom challenge to try to develop leak-detection ideas that would be inexpensive and easily added to…

  8. Improved Portable Ultrasonic Leak Detectors

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C.; Moerk, John S.; Haskell, William D.; Cox, Robert B.; Polk, Jimmy D.; Strobel, James P.; Luaces, Frank

    1995-01-01

    Improved portable ultrasonic leak detector features three interchangeable ultrasonic-transducer modules, each suited for operation in unique noncontact or contact mode. One module equipped with ultrasound-collecting horn for use in scanning to detect leaks from distance; horn provides directional sensitivity pattern with sensitivity multiplied by factor of about 6 in forward direction. Another module similar, does not include horn; this module used for scanning close to suspected leak, where proximity of leak more than offsets loss of sensitivity occasioned by lack of horn. Third module designed to be pressed against leaking vessel; includes rugged stainless-steel shell. Improved detectors perform significantly better, smaller, more rugged, and greater sensitivity.

  9. Hazardous fluid leak detector

    DOEpatents

    Gray, Harold E.; McLaurin, Felder M.; Ortiz, Monico; Huth, William A.

    1996-01-01

    A device or system for monitoring for the presence of leaks from a hazardous fluid is disclosed which uses two electrodes immersed in deionized water. A gas is passed through an enclosed space in which a hazardous fluid is contained. Any fumes, vapors, etc. escaping from the containment of the hazardous fluid in the enclosed space are entrained in the gas passing through the enclosed space and transported to a closed vessel containing deionized water and two electrodes partially immersed in the deionized water. The electrodes are connected in series with a power source and a signal, whereby when a sufficient number of ions enter the water from the gas being bubbled through it (indicative of a leak), the water will begin to conduct, thereby allowing current to flow through the water from one electrode to the other electrode to complete the circuit and activate the signal.

  10. Aspects of leak detection

    SciTech Connect

    Chivers, T.C.

    1997-04-01

    A requirement of a Leak before Break safety case is that the leakage from the through wall crack be detected prior to any growth leading to unacceptable failure. This paper sets out to review some recent developments in this field. It does not set out to be a comprehensive guide to all of the methods available. The discussion concentrates on acoustic emission and how the techniques can be qualified and deployed on operational plant.

  11. Leak test fitting

    DOEpatents

    Pickett, P.T.

    A hollow fitting for use in gas spectrometry leak testing of conduit joints is divided into two generally symmetrical halves along the axis of the conduit. A clip may quickly and easily fasten and unfasten the halves around the conduit joint under test. Each end of the fitting is sealable with a yieldable material, such as a piece of foam rubber. An orifice is provided in a wall of the fitting for the insertion or detection of helium during testing. One half of the fitting also may be employed to test joints mounted against a surface.

  12. Leak test fitting

    DOEpatents

    Pickett, Patrick T.

    1981-01-01

    A hollow fitting for use in gas spectrometry leak testing of conduit joints is divided into two generally symmetrical halves along the axis of the conduit. A clip may quickly and easily fasten and unfasten the halves around the conduit joint under test. Each end of the fitting is sealable with a yieldable material, such as a piece of foam rubber. An orifice is provided in a wall of the fitting for the insertion or detection of helium during testing. One half of the fitting also may be employed to test joints mounted against a surface.

  13. Variable leak gas source

    DOEpatents

    Henderson, Timothy M.; Wuttke, Gilbert H.

    1977-01-01

    A variable leak gas source and a method for obtaining the same which includes filling a quantity of hollow glass micro-spheres with a gas, storing said quantity in a confined chamber having a controllable outlet, heating said chamber above room temperature, and controlling the temperature of said chamber to control the quantity of gas passing out of said controllable outlet. Individual gas filled spheres may be utilized for calibration purposes by breaking a sphere having a known quantity of a known gas to calibrate a gas detection apparatus.

  14. Superfluid helium leak sealant study

    NASA Technical Reports Server (NTRS)

    Vorreiter, J. W.

    1981-01-01

    Twenty-one leak specimens were fabricated in the ends of stainless steel and aluminum tubes. Eighteen of these tubes were coated with a copolymer material to seal the leak. The other three specimens were left uncoated and served as control specimens. All 21 tubes were cold shocked in liquid helium 50 times and then the leak rate was measured while the tubes were submerged in superfluid helium at 1.7 K. During the cold shocks two of the coated specimens were mechanically damaged and eliminated from the test program. Of the remaining 16 coated specimens one suffered a total coating failure and resulting high leak rate. Another three of the coated specimens suffered partial coating failures. The leak rates of the uncoated specimens were also measured and reported. The significance of various leak rates is discussed in view of the infrared astronomical satellite (IRAS) Dewar performance.

  15. Recorded seismic response of Pacific Park Plaza. II. System identification

    USGS Publications Warehouse

    Safak, F.; Celebi, M.

    1992-01-01

    This is the second of two companion papers on the recorded seismic response of the Pacific Park Plaza building, in Emeryville, Calif., during the October 17, 1989, Ms = 7.1 (surface-wave magnitude) Loma Prieta earthquake. In this second part, the recorded data are analyzed in more detail by using system-identification techniques. The three-dimensional behavior and the coupled modes of the building are determined, and the effects of soil-structure interaction are investigated. The study shows that the response of the building is nonlinear at the beginning, and becomes linear after 17 sec into the earthquake. The dominant motion of the building follows an elliptical path oriented in the southeast-northwest direction. Some of the modes are complex, with nonproportional damping, and there are phase differences among modal response components. The fundamental mode of the building is a translation in the southeast-northwest direction at 0.4 Hz, with 13% damping. The wing displacements relative to the center core are large, about 50% of the center core displacements, and indicate significant torsion in the center core. The soil-structure interaction is characterized by a vibration at 0.7 Hz. This is believed to be the fundamental frequency of the surrounding soil medium. The rocking motions of the building are negligible.

  16. SSME propellant path leak detection

    NASA Technical Reports Server (NTRS)

    Crawford, Roger; Shohadaee, Ahmad Ali

    1989-01-01

    The complicated high-pressure cycle of the space shuttle main engine (SSME) propellant path provides many opportunities for external propellant path leaks while the engine is running. This mode of engine failure may be detected and analyzed with sufficient speed to save critical engine test hardware from destruction. The leaks indicate hardware failures which will damage or destroy an engine if undetected; therefore, detection of both cryogenic and hot gas leaks is the objective of this investigation. The primary objective of this phase of the investigation is the experimental validation of techniques for detecting and analyzing propellant path external leaks which have a high probability of occurring on the SSME. The selection of candidate detection methods requires a good analytic model for leak plumes which would develop from external leaks and an understanding of radiation transfer through the leak plume. One advanced propellant path leak detection technique is obtained by using state-of-the-art technology infrared (IR) thermal imaging systems combined with computer, digital image processing, and expert systems for the engine protection. The feasibility of IR leak plume detection is evaluated on subscale simulated laboratory plumes to determine sensitivity, signal to noise, and general suitability for the application.

  17. Chemochromic Hydrogen Leak Detectors

    NASA Technical Reports Server (NTRS)

    Roberson, Luke; Captain, Janine; Williams, Martha; Smith, Trent; Tate, LaNetra; Raissi, Ali; Mohajeri, Nahid; Muradov, Nazim; Bokerman, Gary

    2009-01-01

    At NASA, hydrogen safety is a key concern for space shuttle processing. Leaks of any level must be quickly recognized and addressed due to hydrogen s lower explosion limit. Chemo - chromic devices have been developed to detect hydrogen gas in several embodiments. Because hydrogen is odorless and colorless and poses an explosion hazard, there is an emerging need for sensors to quickly and accurately detect low levels of leaking hydrogen in fuel cells and other advanced energy- generating systems in which hydrogen is used as fuel. The device incorporates a chemo - chromic pigment into a base polymer. The article can reversibly or irreversibly change color upon exposure to hydrogen. The irreversible pigment changes color from a light beige to a dark gray. The sensitivity of the pigment can be tailored to its application by altering its exposure to gas through the incorporation of one or more additives or polymer matrix. Furthermore, through the incorporation of insulating additives, the chemochromic sensor can operate at cryogenic temperatures as low as 78 K. A chemochromic detector of this type can be manufactured into any feasible polymer part including injection molded plastic parts, fiber-spun textiles, or extruded tapes. The detectors are simple, inexpensive, portable, and do not require an external power source. The chemochromic detectors were installed and removed easily at the KSC launch pad without need for special expertise. These detectors may require an external monitor such as the human eye, camera, or electronic detector; however, they could be left in place, unmonitored, and examined later for color change to determine whether there had been exposure to hydrogen. In one type of envisioned application, chemochromic detectors would be fabricated as outer layers (e.g., casings or coatings) on high-pressure hydrogen storage tanks and other components of hydrogen-handling systems to provide visible indications of hydrogen leaks caused by fatigue failures or

  18. Ultrasonic Leak Detection System

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C. (Inventor); Moerk, J. Steven (Inventor)

    1998-01-01

    A system for detecting ultrasonic vibrations. such as those generated by a small leak in a pressurized container. vessel. pipe. or the like. comprises an ultrasonic transducer assembly and a processing circuit for converting transducer signals into an audio frequency range signal. The audio frequency range signal can be used to drive a pair of headphones worn by an operator. A diode rectifier based mixing circuit provides a simple, inexpensive way to mix the transducer signal with a square wave signal generated by an oscillator, and thereby generate the audio frequency signal. The sensitivity of the system is greatly increased through proper selection and matching of the system components. and the use of noise rejection filters and elements. In addition, a parabolic collecting horn is preferably employed which is mounted on the transducer assembly housing. The collecting horn increases sensitivity of the system by amplifying the received signals. and provides directionality which facilitates easier location of an ultrasonic vibration source.

  19. Hermetic Seal Leak Detection Apparatus

    NASA Technical Reports Server (NTRS)

    Kelley, Anthony R. (Inventor)

    2013-01-01

    The present invention is a hermetic seal leak detection apparatus, which can be used to test for hermetic seal leaks in instruments and containers. A vacuum tight chamber is created around the unit being tested to minimize gas space outside of the hermetic seal. A vacuum inducing device is then used to increase the gas chamber volume inside the device, so that a slight vacuum is pulled on the unit being tested. The pressure in the unit being tested will stabilize. If the stabilized pressure reads close to a known good seal calibration, there is not a leak in the seal. If the stabilized pressure reads closer to a known bad seal calibration value, there is a leak in the seal. The speed of the plunger can be varied and by evaluating the resulting pressure change rates and final values, the leak rate/size can be accurately calculated.

  20. Cerebrospinal fluid leaks following septoplasty.

    PubMed

    Venkatesan, Naren N; Mattox, Douglas E; Del Gaudio, John M

    2014-12-01

    We conducted a retrospective review to identify the characteristics of cerebrospinal fluid (CSF) leak in patients who had undergone septoplasty and in selected patients who had experienced a spontaneous CSF leak. CSF leak is a known but infrequently reported complication of septoplasty; to the best of our knowledge, only 4 cases have been previously published in the literature. A review of our institution's database revealed 3 cases of postseptoplasty CSF leak. We reviewed all the available data to look for any commonalities among these 7 cases. In addition, we reviewed 6 cases of spontaneous CSF leak selected from our database for the same purpose. For all patients, we noted the side of the cribriform plate defect, its size and, for the postseptoplasty cases, the interval between the septoplasty and the leak repair. Overall, we found that leaks were much more common on the right side than on the left. The sizes of the leaks in the 2 postseptoplasty groups were comparable (mean: 14.0 × 6.4 mm). The interval between septoplasty and leak repair ranged from 2.5 to 20 years in our cases and from 3 days to 22 weeks in the previously published cases. All 3 of the postseptoplasty patients in our database presented with clear rhinorrhea. Two of the 3 patients had meningitis; 1 of these 2 also had pneumocephalus. Of the 6 cases of spontaneous CSF leaks, 4 occurred on the right and 2 on the left; the average size of the defect was 5.8 mm in the greatest dimension. The finding that cribriform plate defects after septoplasty were typically right-sided likely reflects the prevalence of left-sided surgical approaches. Also, the fact that the defects were larger in the postseptoplasty cases than in the spontaneous cases is likely attributable to the torque effect toward the thin skull base that occurs when the perpendicular plate is twisted during septoplasty.

  1. Expandable coating cocoon leak detection system

    NASA Technical Reports Server (NTRS)

    Hauser, R. L.; Kochansky, M. C.

    1972-01-01

    Development of system and materials for detecting leaks in cocoon protective coatings are discussed. Method of applying materials for leak determination is presented. Pressurization of system following application of materials will cause formation of bubble if leak exists.

  2. A Leak Monitor for Industry

    NASA Technical Reports Server (NTRS)

    1996-01-01

    GenCorp Aerojet Industrial Products, Lewis Research Center, Marshall Space Flight Center, and Case Western Reserve University developed a gas leak detection system, originally for use with the Space Shuttle propulsion system and reusable launch vehicles. The Model HG200 Automated Gas Leak Detection System has miniaturized sensors that can identify extremely low concentrations of hydrogen without requiring oxygen. A microprocessor-based hardware/software system monitors the sensors and displays the source and magnitude of hydrogen leaks in real time. The system detects trace hydrogen around pipes, connectors, flanges and pressure tanks, and has been used by Ford Motor Company in the production of a natural gas-powered car.

  3. Aerospace Payloads Leak Test Methodology

    NASA Technical Reports Server (NTRS)

    Lvovsky, Oleg; Grayson, Cynthia M.

    2010-01-01

    Pressurized and sealed aerospace payloads can leak on orbit. When dealing with toxic or hazardous materials, requirements for fluid and gas leakage rates have to be properly established, and most importantly, reliably verified using the best Nondestructive Test (NDT) method available. Such verification can be implemented through application of various leak test methods that will be the subject of this paper, with a purpose to show what approach to payload leakage rate requirement verification is taken by the National Aeronautics and Space Administration (NASA). The scope of this paper will be mostly a detailed description of 14 leak test methods recommended.

  4. Predictors of alveolar air leaks.

    PubMed

    Loran, David B; Woodside, Kenneth J; Cerfolio, Robert J; Zwischenberger, Joseph B

    2002-08-01

    Persistent air leaks are caused by the failure of the postoperative lung to achieve a configuration that is physiologically amenable to healing. The raw pulmonary surface caused by the dissection of the fissure often is separated from the pleura, and the air leak fails to close. Additionally, higher air flow thorough an alveolar-pleural fistula seems to keep the fistula open. Other factors that interfere with wound healing, such as steroid use, diabetes, or malnutrition, can result in persistence of the leak. A thoracic surgeon can minimize the incidence of air leak through meticulous surgical technique and can identify patients in whom the balance of risks (Table 1) and benefits warrant operative intervention based on an understanding of the underlying pathophysiology.

  5. Leak detection with expandable coatings

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Developed and evaluated is a system for leak detection that can be easily applied over separable connectors and that expands into a bubble or balloon if a leak is present. This objective is accomplished by using thin films of Parafilm tape wrapped over connectors, which are then overcoated with a special formulation. The low yield strength and the high elongation of the envelope permit bubble formation if leakage occurs. This system is appropriate for welds and other hardware besides separable connectors. The practical limit of this system appears to be for leaks exceeding 0.000001 cc/sec. If this envelope is used to trap gases for mass spectrometer inspection, leaks in the range of ten to the minus 8th power cc/sec. may be detectable.

  6. Leak test adapter for containers

    DOEpatents

    Hallett, Brian H.; Hartley, Michael S.

    1996-01-01

    An adapter is provided for facilitating the charging of containers and leak testing penetration areas. The adapter comprises an adapter body and stem which are secured to the container's penetration areas. The container is then pressurized with a tracer gas. Manipulating the adapter stem installs a penetration plug allowing the adapter to be removed and the penetration to be leak tested with a mass spectrometer. Additionally, a method is provided for using the adapter.

  7. Intelligent Leak Detection System

    SciTech Connect

    Mohaghegh, Shahab D.

    2014-10-27

    apability of underground carbon dioxide storage to confine and sustain injected CO2 for a very long time is the main concern for geologic CO2 sequestration. If a leakage from a geological CO2 sequestration site occurs, it is crucial to find the approximate amount and the location of the leak in order to implement proper remediation activity. An overwhelming majority of research and development for storage site monitoring has been concentrated on atmospheric, surface or near surface monitoring of the sequestered CO2. This study aims to monitor the integrity of CO2 storage at the reservoir level. This work proposes developing in-situ CO2 Monitoring and Verification technology based on the implementation of Permanent Down-hole Gauges (PDG) or “Smart Wells” along with Artificial Intelligence and Data Mining (AI&DM). The technology attempts to identify the characteristics of the CO2 leakage by de-convolving the pressure signals collected from Permanent Down-hole Gauges (PDG). Citronelle field, a saline aquifer reservoir, located in the U.S. was considered for this study. A reservoir simulation model for CO2 sequestration in the Citronelle field was developed and history matched. The presence of the PDGs were considered in the reservoir model at the injection well and an observation well. High frequency pressure data from sensors were collected based on different synthetic CO2 leakage scenarios in the model. Due to complexity of the pressure signal behaviors, a Machine Learning-based technology was introduced to build an Intelligent Leakage Detection System (ILDS). The ILDS was able to detect leakage characteristics in a short period of time (less than a day) demonstrating the capability of the system in quantifying leakage characteristics subject to complex rate behaviors. The performance of ILDS was examined under different conditions such as multiple well leakages, cap rock leakage, availability of an additional monitoring well, presence of pressure drift and noise

  8. On common ground: Social memory and the plaza at early Moundville

    NASA Astrophysics Data System (ADS)

    Davis, Jera Rollins

    The Moundville site of west-central Alabama featured one of the largest plazas in the Mississippian world. The construction of Moundville's plaza necessitated the destruction and burial of a prior landscape, obliterating symbols of a contested past at a time when emerging differences in rank and power threatened group cohesion. This dissertation employs landscape-scale geophysical data and targeted excavations to identify what remains of the former settlement and the community plan that replaced it. When the hundreds of previously undocumented buildings are sorted on the basis of architectural style and orientation into chronological categories, it is revealed that dramatic changes in the arrangement of architecture did indeed coincide with the construction of the plaza. Understood from a social memory perspective, this rapid shift is described as an effort to promote inclusivity by selectively reimagining and representing the past. Other conclusions pertain to the division of plaza space into habitation and activity zones and the spatial, historical, and ideological centrality of Moundville's Mound A.

  9. Mitigated Transfer Line Leaks that Result in Surface Pools and Spray Leaks into Pits

    SciTech Connect

    HEY, B.E.

    1999-12-07

    This analysis provides radiological and toxicological consequence calculations for postulated mitigated leaks during transfers of six waste compositions. Leaks in Cleanout Boxes equipped with supplemental covers and leaks in pits are analyzed.

  10. Mapping urban pipeline leaks: methane leaks across Boston.

    PubMed

    Phillips, Nathan G; Ackley, Robert; Crosson, Eric R; Down, Adrian; Hutyra, Lucy R; Brondfield, Max; Karr, Jonathan D; Zhao, Kaiguang; Jackson, Robert B

    2013-02-01

    Natural gas is the largest source of anthropogenic emissions of methane (CH(4)) in the United States. To assess pipeline emissions across a major city, we mapped CH(4) leaks across all 785 road miles in the city of Boston using a cavity-ring-down mobile CH(4) analyzer. We identified 3356 CH(4) leaks with concentrations exceeding up to 15 times the global background level. Separately, we measured δ(13)CH(4) isotopic signatures from a subset of these leaks. The δ(13)CH(4) signatures (mean = -42.8‰ ± 1.3‰ s.e.; n = 32) strongly indicate a fossil fuel source rather than a biogenic source for most of the leaks; natural gas sampled across the city had average δ(13)CH(4) values of -36.8‰ (± 0.7‰ s.e., n = 10), whereas CH(4) collected from landfill sites, wetlands, and sewer systems had δ(13)CH(4) signatures ~20‰ lighter (μ = -57.8‰, ± 1.6‰ s.e., n = 8). Repairing leaky natural gas distribution systems will reduce greenhouse gas emissions, increase consumer health and safety, and save money.

  11. Microbial Health Risks Associated with Exposure to Stormwater in a Water Plaza

    NASA Astrophysics Data System (ADS)

    Sales-Ortells, Helena; Medema, Gertjan

    2015-04-01

    Climate change scenarios predict an increase of intense rainfall events in summer in Western Europe. Current urban drainage systems cannot cope with such intense precipitation events. Cities are constructing local stormwater storage facilities to prevent pluvial flooding. Combining storage with other functions, such as recreation, may lead to exposure to contaminants. This study assessed the microbial quality of rainwater collected in a water plaza in Rotterdam (The Netherlands) and the health risks associated with recreational exposure. The water plaza collects street run-off, diverges first flush to the sewer system and stores the rest of the run-off in the plaza as open water. A rain simulation experiment was conducted using drinking water from fire hydrants. The water flowed over the street pavement into the street gutters and into the square. Samples were collected from the first flush diverted water and from two different levels of the water plaza at different points in time. Campylobacter spp., Cryptosporidium, and Legionella pneumophila were the pathogens investigated, using quantitative PCR. Escherichia coli was quantified with culture methods to obtain information on faecal contamination. Microbial source tracking tools (human Bacteroides, avian Helicobacter and canine mitochondrial DNA, all analysed with quantitative PCR) were used to determine the origin (human, animal) of the intestinal pathogens. To estimate the health risks for children playing in the water plaza after a rain event, a quantitative microbial risk assessment model was built. The volume of water ingested was obtained from literature on similar locations (flooded streets). Published dose-response models were used to calculate the risk per event. Exposure frequency was estimated using weather data (precipitation events). E. coli concentrations were below the level for excellent bathing water in the EU Bathing Water Directive. Cryptosporidium was not found in any sample. Campylobacter spp

  12. Variable gas leak rate valve

    DOEpatents

    Eernisse, Errol P.; Peterson, Gary D.

    1976-01-01

    A variable gas leak rate valve which utilizes a poled piezoelectric element to control opening and closing of the valve. The gas flow may be around a cylindrical rod with a tubular piezoelectric member encircling the rod for seating thereagainst to block passage of gas and for reopening thereof upon application of suitable electrical fields.

  13. Ryanodine receptors as leak channels.

    PubMed

    Guerrero-Hernández, Agustín; Ávila, Guillermo; Rueda, Angélica

    2014-09-15

    Ryanodine receptors are Ca(2+) release channels of internal stores. This review focuses on those situations and conditions that transform RyRs from a finely regulated ion channel to an unregulated Ca(2+) leak channel and the pathological consequences of this alteration. In skeletal muscle, mutations in either CaV1.1 channel or RyR1 results in a leaky behavior of the latter. In heart cells, RyR2 functions normally as a Ca(2+) leak channel during diastole within certain limits, the enhancement of this activity leads to arrhythmogenic situations that are tackled with different pharmacological strategies. In smooth muscle, RyRs are involved more in reducing excitability than in stimulating contraction so the leak activity of RyRs in the form of Ca(2+) sparks, locally activates Ca(2+)-dependent potassium channels to reduce excitability. In neurons the enhanced activity of RyRs is associated with the development of different neurodegenerative disorders such as Alzheimer and Huntington diseases. It appears then that the activity of RyRs as leak channels can have both physiological and pathological consequences depending on the cell type and the metabolic condition.

  14. 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...

  15. Optical Detection Of Cryogenic Leaks

    NASA Technical Reports Server (NTRS)

    Wyett, Lynn M.

    1988-01-01

    Conceptual system identifies leakage without requiring shutdown for testing. Proposed device detects and indicates leaks of cryogenic liquids automatically. Detector makes it unnecessary to shut equipment down so it can be checked for leakage by soap-bubble or helium-detection methods. Not necessary to mix special gases or other materials with cryogenic liquid flowing through equipment.

  16. LOCATING LEAKS WITH ACOUSTIC TECHNOLOGY

    EPA Science Inventory

    Many water distribution systems in this country are almost 100 years old. About 26 percent of piping in these systems is made of unlined cast iron or steel and is in poor condition. Many methods that locate leaks in these pipes are time-consuming, costly, disruptive to operations...

  17. Stochastic Consequence Analysis for Waste Leaks

    SciTech Connect

    HEY, B.E.

    2000-05-31

    This analysis evaluates the radiological consequences of potential Hanford Tank Farm waste transfer leaks. These include ex-tank leaks into structures, underneath the soil, and exposed to the atmosphere. It also includes potential misroutes, tank overflow

  18. Rapid leak detection with liquid crystals

    NASA Technical Reports Server (NTRS)

    Heisman, R. M.; Iceland, W. F.; Ruppe, E. P.

    1978-01-01

    Small leaks in vacuum lines are detected by applying liquid-crystal coating, warming suspected area, and observing color change due to differential cooling by leak jet. Technique is used on inside or outside walls of vacuum-jacketed lines.

  19. Standard Leak Calibration Facility software system

    SciTech Connect

    McClain, S.K.

    1989-06-01

    A Standard Leak Calibration Facility Software System has been developed and implemented for controlling, and running a standard Leak Calibration Facility. Primary capabilities provided by the software system include computer control of the vacuum system, automatic leak calibration, and data acquisition, manipulation, and storage.

  20. Sensitivities of Soap Solutions in Leak Detection

    NASA Technical Reports Server (NTRS)

    Stuck, D.; Lam, D. Q.; Daniels, C.

    1985-01-01

    Document describes method for determining minimum leak rate to which soap-solution leak detectors sensitive. Bubbles formed at smaller leak rates than previously assumed. In addition to presenting test results, document discusses effects of joint-flange configurations, properties of soap solutions, and correlation of test results with earlier data.

  1. PLAZA 3.0: an access point for plant comparative genomics

    PubMed Central

    Proost, Sebastian; Van Bel, Michiel; Vaneechoutte, Dries; Van de Peer, Yves; Inzé, Dirk; Mueller-Roeber, Bernd; Vandepoele, Klaas

    2015-01-01

    Comparative sequence analysis has significantly altered our view on the complexity of genome organization and gene functions in different kingdoms. PLAZA 3.0 is designed to make comparative genomics data for plants available through a user-friendly web interface. Structural and functional annotation, gene families, protein domains, phylogenetic trees and detailed information about genome organization can easily be queried and visualized. Compared with the first version released in 2009, which featured nine organisms, the number of integrated genomes is more than four times higher, and now covers 37 plant species. The new species provide a wider phylogenetic range as well as a more in-depth sampling of specific clades, and genomes of additional crop species are present. The functional annotation has been expanded and now comprises data from Gene Ontology, MapMan, UniProtKB/Swiss-Prot, PlnTFDB and PlantTFDB. Furthermore, we improved the algorithms to transfer functional annotation from well-characterized plant genomes to other species. The additional data and new features make PLAZA 3.0 (http://bioinformatics.psb.ugent.be/plaza/) a versatile and comprehensible resource for users wanting to explore genome information to study different aspects of plant biology, both in model and non-model organisms. PMID:25324309

  2. Hydrogen Leak Detection Sensor Database

    NASA Technical Reports Server (NTRS)

    Baker, Barton D.

    2010-01-01

    This slide presentation reviews the characteristics of the Hydrogen Sensor database. The database is the result of NASA's continuing interest in and improvement of its ability to detect and assess gas leaks in space applications. The database specifics and a snapshot of an entry in the database are reviewed. Attempts were made to determine the applicability of each of the 65 sensors for ground and/or vehicle use.

  3. Schlieren optics for leak detection

    NASA Technical Reports Server (NTRS)

    Peale, Robert E.; Ruffin, Alranzo B.

    1995-01-01

    The purpose of this research was to develop an optical method of leak detection. Various modifications of schlieren optics were explored with initial emphasis on leak detection of the plumbing within the orbital maneuvering system of the space shuttle (OMS pod). The schlieren scheme envisioned for OMS pod leak detection was that of a high contrast pattern on flexible reflecting material imaged onto a negative of the same pattern. We find that the OMS pod geometry constrains the characteristic length scale of the pattern to the order of 0.001 inch. Our experiments suggest that optical modulation transfer efficiency will be very low for such patterns, which will limit the sensitivity of the technique. Optical elements which allow a negative of the scene to be reversibly recorded using light from the scene itself were explored for their potential in adaptive single-ended schlieren systems. Elements studied include photochromic glass, bacteriorhodopsin, and a transmissive liquid crystal display. The dynamics of writing and reading patterns were studied using intensity profiles from recorded images. Schlieren detection of index gradients in air was demonstrated.

  4. Comprehensive quantitative analysis on privacy leak behavior.

    PubMed

    Fan, Lejun; Wang, Yuanzhuo; Jin, Xiaolong; Li, Jingyuan; Cheng, Xueqi; Jin, Shuyuan

    2013-01-01

    Privacy information is prone to be leaked by illegal software providers with various motivations. Privacy leak behavior has thus become an important research issue of cyber security. However, existing approaches can only qualitatively analyze privacy leak behavior of software applications. No quantitative approach, to the best of our knowledge, has been developed in the open literature. To fill this gap, in this paper we propose for the first time four quantitative metrics, namely, possibility, severity, crypticity, and manipulability, for privacy leak behavior analysis based on Privacy Petri Net (PPN). In order to compare the privacy leak behavior among different software, we further propose a comprehensive metric, namely, overall leak degree, based on these four metrics. Finally, we validate the effectiveness of the proposed approach using real-world software applications. The experimental results demonstrate that our approach can quantitatively analyze the privacy leak behaviors of various software types and reveal their characteristics from different aspects.

  5. Comprehensive Quantitative Analysis on Privacy Leak Behavior

    PubMed Central

    Fan, Lejun; Wang, Yuanzhuo; Jin, Xiaolong; Li, Jingyuan; Cheng, Xueqi; Jin, Shuyuan

    2013-01-01

    Privacy information is prone to be leaked by illegal software providers with various motivations. Privacy leak behavior has thus become an important research issue of cyber security. However, existing approaches can only qualitatively analyze privacy leak behavior of software applications. No quantitative approach, to the best of our knowledge, has been developed in the open literature. To fill this gap, in this paper we propose for the first time four quantitative metrics, namely, possibility, severity, crypticity, and manipulability, for privacy leak behavior analysis based on Privacy Petri Net (PPN). In order to compare the privacy leak behavior among different software, we further propose a comprehensive metric, namely, overall leak degree, based on these four metrics. Finally, we validate the effectiveness of the proposed approach using real-world software applications. The experimental results demonstrate that our approach can quantitatively analyze the privacy leak behaviors of various software types and reveal their characteristics from different aspects. PMID:24066046

  6. [Where is a leak point detected by "the low flow leak test" of anesthetic machines?].

    PubMed

    Omija, K; Tokumine, J; Iha, H; Uehara, M; Nitta, K; Okuda, Y

    1997-10-01

    "The low flow leak test" is recommended for pre-anesthetic inspection of anesthetic machines. We carried out anesthesia compression tests as a standard. Even in that case, often the low flow leak test does not meet the standard. We investigated the point where there is a leak in the anesthetic machine. Observing the leak that fluctuates each time there is detachment or attachment of the canister, the primary cause of the leak is thought to be related to the canister. It is important to carry out an inspection of the canister if the low flow leak test does not meet the standard.

  7. Vacuum leak detector and method

    DOEpatents

    Edwards, Jr., David

    1983-01-01

    Apparatus and method for detecting leakage in a vacuum system involves a moisture trap chamber connected to the vacuum system and to a pressure gauge. Moisture in the trap chamber is captured by freezing or by a moisture adsorbent to reduce the residual water vapor pressure therein to a negligible amount. The pressure gauge is then read to determine whether the vacuum system is leaky. By directing a stream of carbon dioxide or helium at potentially leaky parts of the vacuum system, the apparatus can be used with supplemental means to locate leaks.

  8. Thermal Adaptation Methods of Urban Plaza Users in Asia’s Hot-Humid Regions: A Taiwan Case Study

    PubMed Central

    Wu, Chen-Fa; Hsieh, Yen-Fen; Ou, Sheng-Jung

    2015-01-01

    Thermal adaptation studies provide researchers great insight to help understand how people respond to thermal discomfort. This research aims to assess outdoor urban plaza conditions in hot and humid regions of Asia by conducting an evaluation of thermal adaptation. We also propose that questionnaire items are appropriate for determining thermal adaptation strategies adopted by urban plaza users. A literature review was conducted and first hand data collected by field observations and interviews used to collect information on thermal adaptation strategies. Item analysis—Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA)—were applied to refine the questionnaire items and determine the reliability of the questionnaire evaluation procedure. The reliability and validity of items and constructing process were also analyzed. Then, researchers facilitated an evaluation procedure for assessing the thermal adaptation strategies of urban plaza users in hot and humid regions of Asia and formulated a questionnaire survey that was distributed in Taichung’s Municipal Plaza in Taiwan. Results showed that most users responded with behavioral adaptation when experiencing thermal discomfort. However, if the thermal discomfort could not be alleviated, they then adopted psychological strategies. In conclusion, the evaluation procedure for assessing thermal adaptation strategies and the questionnaire developed in this study can be applied to future research on thermal adaptation strategies adopted by urban plaza users in hot and humid regions of Asia. PMID:26516881

  9. Thermal Adaptation Methods of Urban Plaza Users in Asia's Hot-Humid Regions: A Taiwan Case Study.

    PubMed

    Wu, Chen-Fa; Hsieh, Yen-Fen; Ou, Sheng-Jung

    2015-10-27

    Thermal adaptation studies provide researchers great insight to help understand how people respond to thermal discomfort. This research aims to assess outdoor urban plaza conditions in hot and humid regions of Asia by conducting an evaluation of thermal adaptation. We also propose that questionnaire items are appropriate for determining thermal adaptation strategies adopted by urban plaza users. A literature review was conducted and first hand data collected by field observations and interviews used to collect information on thermal adaptation strategies. Item analysis--Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA)--were applied to refine the questionnaire items and determine the reliability of the questionnaire evaluation procedure. The reliability and validity of items and constructing process were also analyzed. Then, researchers facilitated an evaluation procedure for assessing the thermal adaptation strategies of urban plaza users in hot and humid regions of Asia and formulated a questionnaire survey that was distributed in Taichung's Municipal Plaza in Taiwan. Results showed that most users responded with behavioral adaptation when experiencing thermal discomfort. However, if the thermal discomfort could not be alleviated, they then adopted psychological strategies. In conclusion, the evaluation procedure for assessing thermal adaptation strategies and the questionnaire developed in this study can be applied to future research on thermal adaptation strategies adopted by urban plaza users in hot and humid regions of Asia.

  10. Leak detection capability in CANDU reactors

    SciTech Connect

    Azer, N.; Barber, D.H.; Boucher, P.J.

    1997-04-01

    This paper addresses the moisture leak detection capability of Ontario Hydro CANDU reactors which has been demonstrated by performing tests on the reactor. The tests confirmed the response of the annulus gas system (AGS) to the presence of moisture injected to simulate a pressure tube leak and also confirmed the dew point response assumed in leak before break assessments. The tests were performed on Bruce A Unit 4 by injecting known and controlled rates of heavy water vapor. To avoid condensation during test conditions, the amount of moisture which could be injected was small (2-3.5 g/hr). The test response demonstrated that the AGS is capable of detecting and annunciating small leaks. Thus confidence is provided that it would alarm for a growing pressure tube leak where the leak rate is expected to increase to kg/hr rapidly. The measured dew point response was close to that predicted by analysis.

  11. Long-life leak standard assembly

    DOEpatents

    Basford, James A.; Mathis, John E.; Wright, Harlan C.

    1982-01-01

    The present invention is directed to a portable leak standard assembly which is capable of providing a stream of high-purity reference gas at a virtually constant flow rate over an extensive period of time. The leak assembly comprises a high pressure reservoir coupled to a metal leak valve through a valve-controlled conduit. A reproducible leak valve useful in this assembly is provided by a metal tube crimped with a selected pressure loading for forming an orifice in the tube with this orifice being of a sufficient size to provide the selected flow rate. The leak valve assembly is formed of metal so that it can be "baked-out" in a vacuum furnace to rid the reservoir and attendent components of volatile impurities which reduce the efficiency of the leak standard.

  12. Occupational Noise Exposure among Toll Tellers at Toll Plaza in Malaysia

    NASA Astrophysics Data System (ADS)

    Azmi, Sharifah Nadya Syed; Dawal, Siti Zawiah Md; Ya, Tuan Mohammad Yusoff Shah Tuan; Saidin, Hamidi

    2010-10-01

    Toll tellers working at toll plaza have potential of exposure to high noise from the vehicles especially for the peak level of sound emitted by the heavy vehicles. However, occupational exposures in this workplace have not been adequately characterized and identified. Occupational noise exposure among toll tellers at toll plaza was assessed using Sound Level Meter, Noise Dosimeter and through questionnaire survey. These data were combined to estimate the work shift exposure level and health impacts to the toll tellers by using statistical analysis. Noise Dosimeter microphone was located at the hearing zone of the toll teller which working inside the toll booth and full-period measurements were collected for each work shift. The measurements were taken at 20 toll booths from 6.00 am to 2.00 pm for 5 days. 71 respondents participated in the survey to identify the symptoms of noise induced hearing loss and other health related problems among toll tellers. Results of this study indicated that occupational noise exposure among toll tellers for Mean Continuous Equivalent Level, Leq was 79.2±1.4 dB(A), Mean Maximum Level, Lmax was 107.8±3.6 dB(A) and Mean Peak Level, Lpeak was 136.6±9.9 dB. The Peak Level reported statistically significantly at 140 dB, the level of TLV recommended by ACGIH. The research findings indicated that the primary risk exposure to toll tellers comes from noise that emitted from heavy vehicles. Most of the toll tellers show symptoms of noise induced hearing loss and annoyed by the sources of noise at the toll plaza.

  13. Leak detection using structure-borne noise

    NASA Technical Reports Server (NTRS)

    Holland, Stephen D. (Inventor); Chimenti, Dale E. (Inventor); Roberts, Ronald A. (Inventor)

    2010-01-01

    A method for detection and location of air leaks in a pressure vessel, such as a spacecraft, includes sensing structure-borne ultrasound waveforms associated with turbulence caused by a leak from a plurality of sensors and cross correlating the waveforms to determine existence and location of the leak. Different configurations of sensors and corresponding methods can be used. An apparatus for performing the methods is also provided.

  14. High sensitivity leak detection method and apparatus

    DOEpatents

    Myneni, G.R.

    1994-09-06

    An improved leak detection method is provided that utilizes the cyclic adsorption and desorption of accumulated helium on a non-porous metallic surface. The method provides reliable leak detection at superfluid helium temperatures. The zero drift that is associated with residual gas analyzers in common leak detectors is virtually eliminated by utilizing a time integration technique. The sensitivity of the apparatus of this disclosure is capable of detecting leaks as small as 1 [times] 10[sup [minus]18] atm cc sec[sup [minus]1]. 2 figs.

  15. High sensitivity leak detection method and apparatus

    DOEpatents

    Myneni, Ganapatic R.

    1994-01-01

    An improved leak detection method is provided that utilizes the cyclic adsorption and desorption of accumulated helium on a non-porous metallic surface. The method provides reliable leak detection at superfluid helium temperatures. The zero drift that is associated with residual gas analyzers in common leak detectors is virtually eliminated by utilizing a time integration technique. The sensitivity of the apparatus of this disclosure is capable of detecting leaks as small as 1.times.10.sup.-18 atm cc sec.sup.-1.

  16. Safety upgrades plug car leaks

    SciTech Connect

    Not Available

    1993-08-01

    To lessen the chance of a chemical leak occurring during rail transport, some companies are improving tank car sturdiness and safety by adding such features as top-loading valves, on-board monitoring devices, and thicker, more impact-resistant hulls. Results include a dramatic drop in the number of rail incidents and leak tank cars. Chemicals Division of Olin Corporation (Stamford, Connecticut) has assigned its name to a new fleet of chlorine, caustic soda and toluene diisocyanate (TDI) tank cars. Each car carries the company's Care[trademark]Car registered trademark. The upgrade is part of a company-wide quality improvement process started in 1986. The company requires acoustic emissions (AE) testing on all hazardous materials tank cars. If an area has a defect, it expands and makes a slight sound when subjected to stress. In an AE test, cars are subject to simulated bumps and jolts as in rail shipment. Electronic sensors transfer any stress noises onto a computer screen, where an operator can pinpoint the trouble source.

  17. [The current state of leak in anesthetic machines detected by low flow leak tests].

    PubMed

    Uehara, M; Tokumine, J; Iha, H; Nitta, K; Okuda, Y

    1999-05-01

    To assess the current state of leak in anesthetic machines, we selected 66 units of anesthetic machines for inspection and repair from various medical institutions. Based on a newly designed inspection flow chart a low flow leak test for internal circuits of the anesthetic machines was performed. The conventional low flow leak test was also performed for smooth detection of leak for rational evaluation. Only 39% of the anesthetic machines met the standard of the low flow leak tests, and leak was detected in the remaining 61%. The average residual leak mounted to 0.97 l.min-1, with the maximum of 5.3 l.min-1. Canisters, corrugated tubes, and vaporizers were considered the primary causes of leak. After the inspection and repair, leak in 77.5% of the anesthetic machines either disappeared or decreased and the average residual leak dropped to 0.34 l.min-1. However, 47% of the anesthetic machines still failed to meet the standard of the low flow leak tests. To further improve the situation, more detailed inspection and repair are necessary especially for precise detection of the cause of leak in the internal circuit of anesthetic machines which often remains undetected.

  18. Leak checker data logging system

    DOEpatents

    Gannon, J.C.; Payne, J.J.

    1996-09-03

    A portable, high speed, computer-based data logging system for field testing systems or components located some distance apart employs a plurality of spaced mass spectrometers and is particularly adapted for monitoring the vacuum integrity of a long string of a superconducting magnets such as used in high energy particle accelerators. The system provides precise tracking of a gas such as helium through the magnet string when the helium is released into the vacuum by monitoring the spaced mass spectrometers allowing for control, display and storage of various parameters involved with leak detection and localization. A system user can observe the flow of helium through the magnet string on a real-time basis hour the exact moment of opening of the helium input valve. Graph reading can be normalized to compensate for magnet sections that deplete vacuum faster than other sections between testing to permit repetitive testing of vacuum integrity in reduced time. 18 figs.

  19. Leak checker data logging system

    DOEpatents

    Gannon, Jeffrey C.; Payne, John J.

    1996-01-01

    A portable, high speed, computer-based data logging system for field testing systems or components located some distance apart employs a plurality of spaced mass spectrometers and is particularly adapted for monitoring the vacuum integrity of a long string of a superconducting magnets such as used in high energy particle accelerators. The system provides precise tracking of a gas such as helium through the magnet string when the helium is released into the vacuum by monitoring the spaced mass spectrometers allowing for control, display and storage of various parameters involved with leak detection and localization. A system user can observe the flow of helium through the magnet string on a real-time basis hour the exact moment of opening of the helium input valve. Graph reading can be normalized to compensate for magnet sections that deplete vacuum faster than other sections between testing to permit repetitive testing of vacuum integrity in reduced time.

  20. Measuring Pinhole Leaks - A Novel Method

    NASA Technical Reports Server (NTRS)

    Dunn, Carol Anne

    2009-01-01

    Both of the shuttle pads have one of these large liquid hydrogen tanks and the Shuttle program is currently using both pads. However, just recently, there has been increasing concerns over possible air leaks from the outside into the evacuated region. A method to detect leaks involving measuring the change in the boil-off rate of the liquid hydrogen in the tank.

  1. Protecting brazing furnaces from air leaks

    NASA Technical Reports Server (NTRS)

    Armenoff, C. T.; Mckown, R. D.

    1980-01-01

    Inexpensive inert-atmosphere shielding protects vacuum brazing-furnace components that are likely to spring leak. Pipefittings, gages, and valves are encased in transparent plastic shroud inflated with argon. If leak develops, harmless argon will enter vacuum chamber, making it possible to finish ongoing brazing or heat treatment before shutting down for repair.

  2. EPA Needs Leak Detectives in Texas

    EPA Pesticide Factsheets

    DALLAS - (March 15, 2016) Every year more than one trillion gallons of water are wasted by easy-to-fix household leaks. The U.S. Environmental Protection Agency (EPA) is encouraging consumers to Be a leak detective during WaterSense's eighth annua

  3. EPA Needs Leak Detectives in New Mexico

    EPA Pesticide Factsheets

    DALLAS - (March 15, 2016) Every year more than one trillion gallons of water are wasted by easy-to-fix household leaks. The U.S. Environmental Protection Agency (EPA) is encouraging consumers to Be a Leak Detective during WaterSense's eighth annua

  4. Leak detection for underground storage tanks

    SciTech Connect

    Durgin, P.B. ); Young, T.M.

    1993-01-01

    This symposium was held in New Orleans, Louisiana on January 29, 1992. The purpose of this conference was to provide a forum for exchange of state-of-the-art information on leak detection for underground storage tanks that leaked fuel. A widespread concern was protection of groundwater supplies from these leaking tanks. In some cases, the papers report on research that was conducted two or three years ago but has never been adequately directed to the underground storage tank leak-detection audience. In other cases, the papers report on the latest leak-detection research. The symposium was divided into four sessions that were entitled: Internal Monitoring; External Monitoring; Regulations and Standards; and Site and Risk Evaluation. Individual papers have been cataloged separately for inclusion in the appropriate data bases.

  5. Ultrasonic Detectors Safely Identify Dangerous, Costly Leaks

    NASA Technical Reports Server (NTRS)

    2013-01-01

    In 1990, NASA grounded its space shuttle fleet. The reason: leaks detected in the hydrogen fuel systems of the Space Shuttles Atlantis and Columbia. Unless the sources of the leaks could be identified and fixed, the shuttles would not be safe to fly. To help locate the existing leaks and check for others, Kennedy Space Center engineers used portable ultrasonic detectors to scan the fuel systems. As a gas or liquid escapes from a leak, the resulting turbulence creates ultrasonic noise, explains Gary Mohr, president of Elmsford, New York-based UE Systems Inc., a long-time leader in ultrasonic detector technologies. "In lay terms, the leak is like a dog whistle, and the detector is like the dog ear." Because the ultrasound emissions from a leak are highly localized, they can be used not only to identify the presence of a leak but also to help pinpoint a leak s location. The NASA engineers employed UE s detectors to examine the shuttle fuel tanks and solid rocket boosters, but encountered difficulty with the devices limited range-certain areas of the shuttle proved difficult or unsafe to scan up close. To remedy the problem, the engineers created a long-range attachment for the detectors, similar to "a zoom lens on a camera," Mohr says. "If you are on the ground, and the leak is 50 feet away, the detector would now give you the same impression as if you were only 25 feet away." The enhancement also had the effect of reducing background noise, allowing for a clearer, more precise detection of a leak s location.

  6. Blind Leak Detection for Closed Systems

    NASA Technical Reports Server (NTRS)

    Oelgoetz, Peter; Johnson, Ricky; Todd, Douglas; Russell, Samuel; Walker, James

    2003-01-01

    The current inspection technique for locating interstitial leaking in the Space Shuttle Main Engine nozzles is the application of a liquid leak check solution in the openings where the interstitials space between the tubing and the structural jacket vent out the aft end of the nozzle, while its cooling tubes are pressurized to 25 psig with Helium. When a leak is found, it is classified, and if the leak is severe enough the suspect tube is cut open so that a boroscope can be inserted to find the leak point. Since the boroscope can only cover a finite tube length and since it is impossible to identify which tube (to the right or left of the identified interstitial) is leaking, many extra and undesired repairs have been made to fix just one leak. In certain instances when the interstitials are interlinked by poor braze bonding, many interstitials will show indications of leaking from a single source. What is desired is a technique that can identify the leak source so that a single repair can be performed. Dr, Samuel Russell and James Walker, both with NASA/MSFC have developed a thermographic inspection system that addresses a single repair approach. They have teamed with Boeing/Rocketdyne to repackage the inspection processes to be suitable to address full scale Shuttle development and flight hardware and implement the process at NASA centers. The methods and results presented address the thermographic identification of interstitial leaks in the Space Shuttle Main Engine nozzles. A highly sensitive digital infrared camera (capable of detecting a delta temperature difference of 0.025 C) is used to record the cooling effects associated with a leak source, such as a crack or pinhole, hidden within the nozzle wall by observing the inner hot wall surface as the nozzle is pressurized, These images are enhanced by digitally subtracting a thermal reference image taken before pressurization. The method provides a non-intrusive way of locating the tube that is leaking and the

  7. Vacuum leak detection for double bottom tanks

    SciTech Connect

    Hagen, T.; Rials, R.

    1995-12-31

    Double bottom tanks offer strong leak detection advantages. By incorporating the use of vacuum detection between the two bottoms, the tank bottoms can be verified leak free after construction and during tank use. Utilizing vacuum leak detection requires special considerations. In 1992 a tank construction company built 10 tanks for an oil company in Ponca City, Oklahoma. Each of these tanks were built with a double bottom. This paper provides insight into the planning, construction and testing of this type of double bottom design.

  8. Workplace safety in Bangladesh ready-made garment sector: 3 years after the Rana Plaza collapse.

    PubMed

    Barua, Uttama; Ansary, Mehedi Ahmed

    2016-11-18

    Workplace safety is one of the most important issues in industries worldwide, and is endangered by industrial accidents. Different industrial disasters have resulted in several initiatives worldwide to protect human life and reduce material damage, both nationally and internationally. In Bangladesh, the ready-made garment (RMG) industry is one of the most important export-oriented business sectors, which is facing challenges to ensure workplace safety. The Rana Plaza collapse in Bangladesh is the consequence of such non-compliance. The accident resulted in different local and global initiatives to address the challenges. This article reviews progress and achievement of the initiatives to reduce vulnerability in the Bangladesh RMG industry within 3 years after the deadly accident. In the long run, the challenge is to maintain momentum already created for achieving sustainability in the RMG sector in Bangladesh and maintaining compliance even after the end of support from external partners.

  9. The newly expanded KSC Visitors Complex features a new ticket plaza, information center, exhibits an

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Part of the $13 million expansion to KSC's Visitor Complex, the new information center welcomes visitors to the Gateway to the Universe. The five large video walls provide an orientation video, shown here with photos of John Glenn in his historic Shuttle mission in October 1998, with an introduction to the range of activities and exhibits, plus honor the center's namesake, President John F. Kennedy. Other new additions include a walk-through Robot Scouts exhibit, a wildlife exhibit, and the film Quest for Life in a new 300-seat theater, plus an International Space Station-themed ticket plaza, featuring a structure of overhanging solar panels and astronauts performing assembly tasks. The KSC Visitor Complex was inaugurated three decades ago and is now one of the top five tourist attractions in Florida. It is located on S.R. 407, east of I-95, within the Merritt Island National Wildlife Refuge.

  10. The newly expanded KSC Visitors Complex features a new ticket plaza, information center, exhibits an

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Part of the $13 million expansion to KSC's Visitor Complex, the new information center welcomes visitors to the Gateway to the Universe. The five large video walls provide an orientation video, with an introduction to the range of activities and exhibits, and honor the center's namesake, President John F. Kennedy. Other additions include a walk-through Robot Scouts exhibit, a wildlife exhibit, and the film Quest for Life in a new 300-seat theater, plus an International Space Station-themed ticket plaza, featuring a structure of overhanging solar panels and astronauts performing assembly tasks. The KSC Visitor Complex was inaugurated three decades ago and is now one of the top five tourist attractions in Florida. It is located on S.R. 407, east of I-95, within the Merritt Island National Wildlife Refuge.

  11. The newly expanded KSC Visitors Complex features a new ticket plaza, information center, exhibits an

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Part of the $13 million expansion to KSC's Visitor Complex, the new information center welcomes visitors to the Gateway to the Universe. The five large video walls provide an orientation video, with an introduction to the range of activities and exhibits, and honor the center's namesake, President John F. Kennedy. Other new additions include a walk-through Robot Scouts exhibit, a wildlife exhibit, and the film Quest for Life in a new 300-seat theater, and an International Space Station-themed ticket plaza, featuring a structure of overhanging solar panels and astronauts performing assembly tasks. The KSC Visitor Complex was inaugurated three decades ago and is now one of the top five tourist attractions in Florida. It is located on S.R. 407, east of I-95, within the Merritt Island National Wildlife Refuge.

  12. Environmental policy -- A leaking drum?

    SciTech Connect

    Bishop, J.

    1995-07-01

    Twenty years ago, the US had virtually no overall environmental policy. Since then, one has evolved as a result of accumulated legislation, much of which was crafted in reaction to specific events, typically real or potential disasters. The familiar names of Love Canal, Times Beach, Bhopal and others are the symbolic anchor points of that evolution, which yielded Superfund, the Resource Conservation and Recovery Act, the Superfund Amendments and Reauthorization Act, and other environmental statutes. The laws in each case were developed in response to particular environmental and health issues--clean water for drinking and recreation, unpolluted air, safe production of chemicals and chemical-based products. The result was a growing body of environmental legislation that eventually became an accumulate of requirements lacking internal consistency or coherence. Because policymaking followed, rather than guided, legislative actions, the policy itself became inconsistent and sometimes illogical. Like a drum that gradually and indiscriminately is filled with a mixture of mutually reactive chemicals, environmental policy increasingly became a volatile source of concern for those industries in whose midst it had been placed. Lately, there is growing consensus that the drum not only has been overfilled, it also is leaking.

  13. Leaking Underground Storage Tank (LUST) Trust Fund

    EPA Pesticide Factsheets

    In 1986, Congress created the Leaking Underground Storage Tank (LUST) Trust Fund to address releases from federally regulated underground storage tanks (USTs) by amending Subtitle I of the Solid Waste Disposal Act.

  14. Leak Detectives Saving Money, Water in Virginia

    EPA Pesticide Factsheets

    “Circuit riders” from the Virginia Rural Water Association (VRWA) are traveling to small communities across the Commonwealth using special equipment financed by EPA to locate expensive and wasteful leaks in drinking water distribution systems.

  15. mpileaks - an MPI opject leak debugging library

    SciTech Connect

    Leon, E. A.

    2011-11-14

    The mpileaks tool is to be used by MPI application developers to track and report leaked MPI objects, such as requests, groups, and datatypes. This debugging tool is useful as a quality assurance check for MPI applications, or it can be used to identify leaks fatal to long-running MPI applications. It provides an efficient method to report bugs that are otherwise fifficult to identify.

  16. Leak detection in pipelines using cepstrum analysis

    NASA Astrophysics Data System (ADS)

    Taghvaei, M.; Beck, S. B. M.; Staszewski, W. J.

    2006-02-01

    The detection and location of leaks in pipeline networks is a major problem and the reduction of these leaks has become a major priority for pipeline authorities around the world. Although the reasons for these leaks are well known, some of the current methods for locating and identifying them are either complicated or imprecise; most of them are time consuming. The work described here shows that cepstrum analysis is a viable approach to leak detection and location in pipeline networks. The method uses pressure waves caused by quickly opening and closing a solenoid valve. Due to their simplicity and robustness, transient analyses provide a plausible route towards leak detection. For this work, the time domain signals of these pressure transients were obtained using a single pressure transducer. These pressure signals were first filtered using discrete wavelets to remove the dc offset, and the low and high frequencies. They were then analysed using a cepstrum method which identified the time delay between the initial wave and its reflections. There were some features in the processed results which can be ascribed to features in the pipeline network such as junctions and pipe ends. When holes were drilled in the pipe, new peaks occurred which identified the presence of a leak in the pipeline network. When tested with holes of different sizes, the amplitude of the processed peak was seen to increase as the cube root of the leak diameter. Using this method, it is possible to identify leaks that are difficult to find by other methods as they are small in comparison with the flow through the pipe.

  17. Modeling Leaking Gas Plume Migration

    SciTech Connect

    Silin, Dmitriy; Patzek, Tad; Benson, Sally M.

    2007-08-20

    In this study, we obtain simple estimates of 1-D plume propagation velocity taking into account the density and viscosity contrast between CO{sub 2} and brine. Application of the Buckley-Leverett model to describe buoyancy-driven countercurrent flow of two immiscible phases leads to a transparent theory predicting the evolution of the plume. We obtain that the plume does not migrate upward like a gas bubble in bulk water. Rather, it stretches upward until it reaches a seal or until the fluids become immobile. A simple formula requiring no complex numerical calculations describes the velocity of plume propagation. This solution is a simplification of a more comprehensive theory of countercurrent plume migration that does not lend itself to a simple analytical solution (Silin et al., 2006). The range of applicability of the simplified solution is assessed and provided. This work is motivated by the growing interest in injecting carbon dioxide into deep geological formations as a means of avoiding its atmospheric emissions and consequent global warming. One of the potential problems associated with the geologic method of sequestration is leakage of CO{sub 2} from the underground storage reservoir into sources of drinking water. Ideally, the injected green-house gases will stay in the injection zone for a geologically long time and eventually will dissolve in the formation brine and remain trapped by mineralization. However, naturally present or inadvertently created conduits in the cap rock may result in a gas leak from primary storage. Even in supercritical state, the carbon dioxide viscosity and density are lower than those of the indigenous formation brine. Therefore, buoyancy will tend to drive the CO{sub 2} upward unless it is trapped beneath a low permeability seal. Theoretical and experimental studies of buoyancy-driven supercritical CO{sub 2} flow, including estimation of time scales associated with plume evolution, are critical for developing technology

  18. Automated Hydrogen Gas Leak Detection System

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Gencorp Aerojet Automated Hydrogen Gas Leak Detection System was developed through the cooperation of industry, academia, and the Government. Although the original purpose of the system was to detect leaks in the main engine of the space shuttle while on the launch pad, it also has significant commercial potential in applications for which there are no existing commercial systems. With high sensitivity, the system can detect hydrogen leaks at low concentrations in inert environments. The sensors are integrated with hardware and software to form a complete system. Several of these systems have already been purchased for use on the Ford Motor Company assembly line for natural gas vehicles. This system to detect trace hydrogen gas leaks from pressurized systems consists of a microprocessor-based control unit that operates a network of sensors. The sensors can be deployed around pipes, connectors, flanges, and tanks of pressurized systems where leaks may occur. The control unit monitors the sensors and provides the operator with a visual representation of the magnitude and locations of the leak as a function of time. The system can be customized to fit the user's needs; for example, it can monitor and display the condition of the flanges and fittings associated with the tank of a natural gas vehicle.

  19. Single-Shell Tanks Leak Integrity Elements/ SX Farm Leak Causes and Locations - 12127

    SciTech Connect

    Girardot, Crystal; Harlow, Don; Venetz, Theodore; Washenfelder, Dennis; Johnson, Jeremy

    2012-07-01

    Washington River Protection Solutions, LLC (WRPS) developed an enhanced single-shell tank (SST) integrity project in 2009. An expert panel on SST integrity was created to provide recommendations supporting the development of the project. One primary recommendation was to expand the leak assessment reports (substitute report or LD-1) to include leak causes and locations. The recommendation has been included in the M-045-91F Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) as one of four targets relating to SST leak integrity. The 241-SX Farm (SX Farm) tanks with leak losses were addressed on an individual tank basis as part of LD-1. Currently, 8 out of 23 SSTs that have been reported to having a liner leak are located in SX Farm. This percentage was the highest compared to other tank farms which is why SX Farm was analyzed first. The SX Farm is comprised of fifteen SSTs built 1953-1954. The tanks are arranged in rows of three tanks each, forming a cascade. Each of the SX Farm tanks has a nominal 1-million-gal storage capacity. Of the fifteen tanks in SX Farm, an assessment reported leak losses for the following tanks: 241-SX-107, 241-SX-108, 241-SX-109, 241-SX- 111, 241-SX-112, 241-SX-113, 241-SX-114 and 241-SX-115. The method used to identify leak location consisted of reviewing in-tank and ex-tank leak detection information. This provided the basic data identifying where and when the first leaks were detected. In-tank leak detection consisted of liquid level measurement that can be augmented with photographs which can provide an indication of the vertical leak location on the sidewall. Ex-tank leak detection for the leaking tanks consisted of soil radiation data from laterals and dry-wells near the tank. The in-tank and ex-tank leak detection can provide an indication of the possible leak location radially around and under the tank. Potential leak causes were determined using in-tank and ex-tank information that is not directly related to

  20. SINGLE-SHELL TANKS LEAK INTEGRITY ELEMENTS/SX FARM LEAK CAUSES AND LOCATIONS - 12127

    SciTech Connect

    VENETZ TJ; WASHENFELDER D; JOHNSON J; GIRARDOT C

    2012-01-25

    Washington River Protection Solutions, LLC (WRPS) developed an enhanced single-shell tank (SST) integrity project in 2009. An expert panel on SST integrity was created to provide recommendations supporting the development of the project. One primary recommendation was to expand the leak assessment reports (substitute report or LD-1) to include leak causes and locations. The recommendation has been included in the M-045-9IF Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) as one of four targets relating to SST leak integrity. The 241-SX Farm (SX Farm) tanks with leak losses were addressed on an individual tank basis as part of LD-1. Currently, 8 out of 23 SSTs that have been reported to having a liner leak are located in SX Farm. This percentage was the highest compared to other tank farms which is why SX Farm was analyzed first. The SX Farm is comprised of fifteen SSTs built 1953-1954. The tanks are arranged in rows of three tanks each, forming a cascade. Each of the SX Farm tanks has a nominal I-million-gal storage capacity. Of the fifteen tanks in SX Farm, an assessment reported leak losses for the following tanks: 241-SX-107, 241-SX-108, 241-SX-109, 241-SX-111, 241-SX-112, 241-SX-113, 241-SX-114 and 241-SX-115. The method used to identify leak location consisted of reviewing in-tank and ex-tank leak detection information. This provided the basic data identifying where and when the first leaks were detected. In-tank leak detection consisted of liquid level measurement that can be augmented with photographs which can provide an indication of the vertical leak location on the sidewall. Ex-tank leak detection for the leaking tanks consisted of soil radiation data from laterals and drywells near the tank. The in-tank and ex-tank leak detection can provide an indication of the possible leak location radially around and under the tank. Potential leak causes were determined using in-tank and ex-tank information that is not directly related to

  1. EPA Chases Leaks in Arkansas during Seventh Annual Fix a Leak Week

    EPA Pesticide Factsheets

    Central Arkansas Water is offering free leak repairs and rain gauges to low-income or elderly customers throughout Little Rock and North Little Rock. They will also giveaway promotional items such as low-flow showerheads, faucet aerators and toilet leak de

  2. Operational Philosophy Concerning Manned Spacecraft Cabin Leaks

    NASA Technical Reports Server (NTRS)

    DeSimpelaere, Edward

    2011-01-01

    The last thirty years have seen the Space Shuttle as the prime United States spacecraft for manned spaceflight missions. Many lessons have been learned about spacecraft design and operation throughout these years. Over the next few decades, a large increase of manned spaceflight in the commercial sector is expected. This will result in the exposure of commercial crews and passengers to many of the same risks crews of the Space Shuttle have encountered. One of the more dire situations that can be encountered is the loss of pressure in the habitable volume of the spacecraft during on orbit operations. This is referred to as a cabin leak. This paper seeks to establish a general cabin leak response philosophy with the intent of educating future spacecraft designers and operators. After establishing a relative definition for a cabin leak, the paper covers general descriptions of detection equipment, detection methods, and general operational methods for management of a cabin leak. Subsequently, all these items are addressed from the perspective of the Space Shuttle Program, as this will be of the most value to future spacecraft due to similar operating profiles. Emphasis here is placed upon why and how these methods and philosophies have evolved to meet the Space Shuttle s needs. This includes the core ideas of: considerations of maintaining higher cabin pressures vs. lower cabin pressures, the pros and cons of a system designed to feed the leak with gas from pressurized tanks vs. using pressure suits to protect against lower cabin pressures, timeline and consumables constraints, re-entry considerations with leaks of unknown origin, and the impact the International Space Station (ISS) has had to the standard Space Shuttle cabin leak response philosophy. This last item in itself includes: procedural management differences, hardware considerations, additional capabilities due to the presence of the ISS and its resource, and ISS docking/undocking considerations with a

  3. ICPP water inventory study leak test report

    SciTech Connect

    Richards, B.T.

    1993-12-01

    Data from the Idaho Chemical Processing Plant (ICPP) indicate that there are three areas where perched water bodies (groundwater) are suspect to exist beneath the ICPP. Questions have been raised concerning the recharge sources for the northwest (NW) perched water body which is located below the northwest area of the ICPP. In response to these questions, a Water Inventory Study was initiated to determine the extent and the potential impacts of the ICPP water systems as a recharge source. A key part of the Water Inventory Study was the leak test investigation, performed to leak test the ICPP water piping distribution system, or portions thereof, which could potentially contribute to the recharge of the NW perched water body. This report provides an overview and the results of the leak test investigation and will be incorporated into the overall Water Inventory Study Report.

  4. Remote Leak Detection: Indirect Thermal Technique

    NASA Technical Reports Server (NTRS)

    Clements, Sandra

    2002-01-01

    Remote sensing technologies are being considered for efficient, low cost gas leak detection. Eleven specific techniques have been identified for further study and evaluation of several of these is underway. The Indirect Thermal Technique is one of the techniques that is being explored. For this technique, an infrared camera is used to detect the temperature change of a pipe or fitting at the site of a gas leak. This temperature change is caused by the change in temperature of the gas expanding from the leak site. During the 10-week NFFP program, the theory behind the technique was further developed, experiments were performed to determine the conditions for which the technique might be viable, and a proof-of-concept system was developed and tested in the laboratory.

  5. Spontaneous cerebrospinal fluid leak at the clivus

    PubMed Central

    Składzien, Jacek; Betlej, Marek; Chrzan, Robert; Mika, Joanna

    2015-01-01

    We present a case report of a 60-year-old woman with a spontaneous cerebrospinal fluid leak at the clivus, obesity and no history of trauma. Follow-up imaging scans confirmed enlargement of the defect within the posterior clival framework to the size of 16 × 9 × 4 mm with a suspected meningocerebral hernia. The surgeons used the “two nostrils – four hands” endoscopic operating technique. The patient reported a history of cerebrospinal fluid leaks lasting for 3 years, with increasingly shorter leak-free periods and an increasing incidence of inflammatory complications. The patient recovered without complications, and she was discharged 14 days after the surgery. Good local outcome and improved patient condition were achieved postoperatively. PMID:26865899

  6. Endoscopic stenting for laparoscopic sleeve gastrectomy leaks

    PubMed Central

    Aydın, Mehmet Timuçin; Alahdab, Yeşim Özen; Aras, Orhan; Karip, Bora; Onur, Ender; İşcan, Yalın; Memişoğlu, Kemal

    2016-01-01

    Objective Laparoscopic sleeve gastrectomy is a widely accepted and effective bariatric surgery method. The rate of leakage at the staple-line has been reported to be between 1.5 and 5%. Aside from the use of percutaneous drainage, re-laparoscopy, or abdominal sepsis control by laparotomy, endoscopic esophagogastric stent placement is increasingly preferred as a treatment method. Because laparoscopic sleeve gastrectomy is a widely used modality in our hospital, we aimed to evaluate the rate of leaks and the results of stent placements in our patients. Material and Methods Between January 1st 2010 and August 31st 2014, laparoscopic sleeve gastrectomy was performed on 236 patients by three surgeons. The demographic information and postoperative discharge summaries were collected and analyzed with the permission of the hospital ethics committee. Information about leak treatment management was also collected. Results Leaks after laparoscopic sleeve gastrectomy in four patients were stented in the first postoperative month. Short (12 cm) Hanora® (M.I.Tech, Gyeonggi-do, Korea) self-expandable coated stents were placed in two patients, and long (24 cm) Hanora® self-expandable coated stents were placed in the other two. The stents were removed after one month in two patients, two and a half months later in one, and five months later in another patient. The leaks were demonstrated to be healed in all patients after stent removal. Endoscopic stent revision was performed in one patient due to migration of the stent and in another for stent breakage. Conclusion The success rate of treatment of leaks after laparoscopic sleeve gastrectomy by stent placement has been variable in the literature. The success in early stent placement has been shown to be related to physician expertise. According to the results of our patients, we suggest that endoscopic stent placement in the early stage after controlling sepsis is an effective method in the management of leaks. PMID:28149125

  7. Apparatus for Leak Testing Pressurized Hoses

    NASA Technical Reports Server (NTRS)

    Underwood, Steve D. (Inventor); Garrison, Steve G. (Inventor); Gant, Bobby D. (Inventor); Palmer, John R. (Inventor)

    2015-01-01

    A hose-attaching apparatus for leak-testing a pressurized hose may include a hose-attaching member. A bore may extend through the hose-attaching member. An internal annular cavity may extend coaxially around the bore. At least one of a detector probe hole and a detector probe may be connected to the internal annular cavity. At least a portion of the bore may have a diameter which is at least one of substantially equal to and less than a diameter of a hose to be leak-tested.

  8. Technique for detecting liquid metal leaks

    DOEpatents

    Bauerle, James E.

    1979-01-01

    In a system employing flowing liquid metal as a heat transfer medium in contact with tubular members containing a working fluid, i.e., steam, liquid metal leaks through the wall of the tubular member are detected by dislodging the liquid metal compounds forming in the tubular member at the leak locations and subsequently transporting the dislodged compound in the form of an aerosol to a detector responsive to the liquid metal compound. In the application to a sodium cooled tubular member, the detector would consist of a sodium responsive device, such as a sodium ion detector.

  9. Single-Shell Tank Leak Integrity Summary

    SciTech Connect

    Harlow, D. G.; Girardot, C. L.; Venetz, T. J.

    2015-03-26

    This document summarizes and evaluates the information in the Hanford Tri-Party Agreement Interim Milestone M-045-91F Targets completed between 2010 and 2015. 1) Common factors of SST liner failures (M-045-91F-T02), 2) the feasibility of testing for ionic conductivity between the inside and outside of SSTs (M-045-91F-T03, and 3) the causes, locations, and rates of leaks from leaking SSTs (M-045-91F-T04).

  10. COPPER PITTING AND PINHOLE LEAK RESEARCH STUDY

    EPA Science Inventory

    Localized copper corrosion or pitting is a significant problem at many water utilities across the United States. Copper pinhole leak problems resulting from extensive pitting are widely under reported. Given the sensitive nature of the problem, extent of damage possible, costs o...

  11. Microphone Detects Boiler-Tube Leaks

    NASA Technical Reports Server (NTRS)

    Parthasarathy, S. P.

    1985-01-01

    Unit simple, sensitive, rugged, and reliable. Diaphragmless microphone detects leaks from small boiler tubes. Porous plug retains carbon granules in tube while allowing pressure changes to penetrate to granules. Has greater life expectancy than previous controllers and used in variety of hot corrosive atmospheres.

  12. [Ryanodine receptor, calcium leak and arrhythmias].

    PubMed

    Rueda, Angélica; de Alba-Aguayo, David R; Valdivia, Héctor H

    2014-01-01

    The participation of the ionic Ca(2+) release channel/ryanodine receptor in cardiac excitation-contraction coupling is well known since the late '80s, when various seminal papers communicated its purification for the first time and its identity with the "foot" structures located at the terminal cisternae of the sarcoplasmic reticulum. In addition to its main role as the Ca(2+) channel responsible for the transient Ca(2+) increase that activates the contractile machinery of the cardiomyocytes, the ryanodine receptor releases Ca(2+) during the relaxation phase of the cardiac cycle, giving rise to a diastolic Ca(2+) leak. In normal physiological conditions, diastolic Ca(2+) leak regulates the proper level of luminal Ca(2+), but in pathological conditions it participates in the generation of both, acquired and hereditary arrhythmias. Very recently, several groups have focused their efforts into the development of pharmacological tools to control the altered diastolic Ca(2+) leak via ryanodine receptors. In this review, we focus our interest on describing the participation of cardiac ryanodine receptor in the diastolic Ca(2+) leak under physiological or pathological conditions and also on the therapeutic approaches to control its undesired exacerbated activity during diastole.

  13. The leak location package for assessment of the time-frequency correlation method for leak location

    NASA Astrophysics Data System (ADS)

    Faerman, V. A.; Cheremnov, A. G.; Avramchuk, V. S.; Shepetovsky, D. V.

    2017-01-01

    The paper describes the simplest implementation of a software and hardware package for acoustic correlation leak location and results of its performance assessment for location of water leaks from a metallic pipe in laboratory conditions. A distinctive feature of this leak locator is the use of the software based on the time-frequency correlation analysis of signals, which was proposed in our previous papers. Comparative analysis results are given for the information content of classical and time-frequency cross-correlation functions as obtained during processing of experimental data. The results obtained justify comparatively higher efficiency of a time-frequency cross correlation method to solve the leak location task. Improved efficiency is determined by bandpass filtration embedded into the time-frequency cross-correlation function calculation.

  14. Modeling leaks from liquid hydrogen storage systems.

    SciTech Connect

    Winters, William Stanley, Jr.

    2009-01-01

    This report documents a series of models for describing intended and unintended discharges from liquid hydrogen storage systems. Typically these systems store hydrogen in the saturated state at approximately five to ten atmospheres. Some of models discussed here are equilibrium-based models that make use of the NIST thermodynamic models to specify the states of multiphase hydrogen and air-hydrogen mixtures. Two types of discharges are considered: slow leaks where hydrogen enters the ambient at atmospheric pressure and fast leaks where the hydrogen flow is usually choked and expands into the ambient through an underexpanded jet. In order to avoid the complexities of supersonic flow, a single Mach disk model is proposed for fast leaks that are choked. The velocity and state of hydrogen downstream of the Mach disk leads to a more tractable subsonic boundary condition. However, the hydrogen temperature exiting all leaks (fast or slow, from saturated liquid or saturated vapor) is approximately 20.4 K. At these temperatures, any entrained air would likely condense or even freeze leading to an air-hydrogen mixture that cannot be characterized by the REFPROP subroutines. For this reason a plug flow entrainment model is proposed to treat a short zone of initial entrainment and heating. The model predicts the quantity of entrained air required to bring the air-hydrogen mixture to a temperature of approximately 65 K at one atmosphere. At this temperature the mixture can be treated as a mixture of ideal gases and is much more amenable to modeling with Gaussian entrainment models and CFD codes. A Gaussian entrainment model is formulated to predict the trajectory and properties of a cold hydrogen jet leaking into ambient air. The model shows that similarity between two jets depends on the densimetric Froude number, density ratio and initial hydrogen concentration.

  15. 40 CFR 86.328-79 - Leak checks.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... checks. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is...

  16. 40 CFR 86.328-79 - Leak checks.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... checks. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is...

  17. REFLEAK: NIST Leak/Recharge Simulation Program for Refrigerant Mixtures

    National Institute of Standards and Technology Data Gateway

    SRD 73 NIST REFLEAK: NIST Leak/Recharge Simulation Program for Refrigerant Mixtures (PC database for purchase)   REFLEAK estimates composition changes of zeotropic mixtures in leak and recharge processes.

  18. 49 CFR 230.64 - Leaks under lagging.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Steam Leaks § 230.64 Leaks under lagging. The steam locomotive owner and/or operator shall take out...

  19. 49 CFR 230.64 - Leaks under lagging.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Steam Leaks § 230.64 Leaks under lagging. The steam locomotive owner and/or operator shall take out...

  20. 49 CFR 230.64 - Leaks under lagging.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Steam Leaks § 230.64 Leaks under lagging. The steam locomotive owner and/or operator shall take out...

  1. 49 CFR 230.64 - Leaks under lagging.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Steam Leaks § 230.64 Leaks under lagging. The steam locomotive owner and/or operator shall take out...

  2. Experiences with leak rate calculations methods for LBB application

    SciTech Connect

    Grebner, H.; Kastner, W.; Hoefler, A.; Maussner, G.

    1997-04-01

    In this paper, three leak rate computer programs for the application of leak before break analysis are described and compared. The programs are compared to each other and to results of an HDR Reactor experiment and two real crack cases. The programs analyzed are PIPELEAK, FLORA, and PICEP. Generally, the different leak rate models are in agreement. To obtain reasonable agreement between measured and calculated leak rates, it was necessary to also use data from detailed crack investigations.

  3. The Prevention and Management of Air Leaks Following Pulmonary Resection.

    PubMed

    Burt, Bryan M; Shrager, Joseph B

    2015-11-01

    Alveolar air leaks are a common problem in the daily practice of thoracic surgeons. Prolonged air leak following pulmonary resection is associated with increased morbidity, increased length of hospital stay, and increased costs. This article reviews the evidence for the various intraoperative and postoperative options to prevent and manage postoperative air leak.

  4. 1999 Leak Detection and Monitoring and Mitigation Strategy Update

    SciTech Connect

    OHL, P.C.

    1999-09-23

    This document is a complete revision of WHC-SD-WM-ES-378, Rev 1. This update includes recent developments in Leak Detection, Leak Monitoring, and Leak Mitigation technologies, as well as, recent developments in single-shell tank retrieval technologies. In addition, a single-shell tank retrieval release protection strategy is presented.

  5. 10 CFR 39.35 - Leak testing of sealed sources.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Leak testing of sealed sources. 39.35 Section 39.35 Energy....35 Leak testing of sealed sources. (a) Testing and recordkeeping requirements. Each licensee who uses... Commission for 3 years after the leak test is performed. (b) Method of testing. The wipe of a sealed...

  6. 10 CFR 39.35 - Leak testing of sealed sources.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Leak testing of sealed sources. 39.35 Section 39.35 Energy....35 Leak testing of sealed sources. (a) Testing and recordkeeping requirements. Each licensee who uses... Commission for 3 years after the leak test is performed. (b) Method of testing. The wipe of a sealed...

  7. Double Shell Tank AY-102 Radioactive Waste Leak Investigation

    SciTech Connect

    Washenfelder, Dennis J.

    2014-04-10

    PowerPoint. The objectives of this presentation are to: Describe Effort to Determine Whether Tank AY-102 Leaked; Review Probable Causes of the Tank AY-102 Leak; and, Discuss Influence of Leak on Hanford’s Double-Shell Tank Integrity Program.

  8. Effect of heat leaks in platinum resistance thermometry.

    PubMed

    Goldratt, E; Yeshurun, Y; Greenfield, A J

    1980-03-01

    The effect of heat leaks in platinum resistance thermometry is analyzed. An experimental method is proposed for estimating the magnitude of this effect. Results are reported for the measurement of the temperature of a hot, solid body under different heat-leak configurations. Design criteria for thermometers are presented which minimize the effect of such heat leaks.

  9. Effect of heat leaks in platinum resistance thermometry

    NASA Astrophysics Data System (ADS)

    Goldratt, E.; Yeshurun, Y.; Greenfield, A. J.

    1980-03-01

    The effect of heat leaks in platinum resistance thermometry is analyzed. An experimental method is proposed for estimating the magnitude of this effect. Results are reported for the measurement of the temperature of a hot, solid body under different heat-leak configurations. Design criteria for thermometers are presented which minimize the effect of such heat leaks.

  10. 49 CFR 195.134 - CPM leak detection.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false CPM leak detection. 195.134 Section 195.134... PIPELINE Design Requirements § 195.134 CPM leak detection. This section applies to each hazardous liquid... computational pipeline monitoring (CPM) leak detection system and each replaced component of an existing...

  11. 49 CFR 195.134 - CPM leak detection.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false CPM leak detection. 195.134 Section 195.134... PIPELINE Design Requirements § 195.134 CPM leak detection. This section applies to each hazardous liquid... computational pipeline monitoring (CPM) leak detection system and each replaced component of an existing...

  12. 49 CFR 195.444 - CPM leak detection.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false CPM leak detection. 195.444 Section 195.444... PIPELINE Operation and Maintenance § 195.444 CPM leak detection. Each computational pipeline monitoring (CPM) leak detection system installed on a hazardous liquid pipeline transporting liquid in...

  13. 49 CFR 195.444 - CPM leak detection.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false CPM leak detection. 195.444 Section 195.444... PIPELINE Operation and Maintenance § 195.444 CPM leak detection. Each computational pipeline monitoring (CPM) leak detection system installed on a hazardous liquid pipeline transporting liquid in...

  14. Leak Detection and Location Technology Assessment for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Wilson, William C.; Coffey, Neil C.; Madaras, Eric I.

    2008-01-01

    Micro Meteoroid and Orbital Debris (MMOD) and other impacts can cause leaks in the International Space Station and other aerospace vehicles. The early detection and location of leaks is paramount to astronaut safety. Therefore this document surveys the state of the art in leak detection and location technology for aerospace vehicles.

  15. Instrumentation system to implement leak test program

    SciTech Connect

    Turner, W.J.; Brown, R.; Rael, D.

    1997-05-01

    HVAC equipment, gloveboxes, and other types of enclosures are required to meet rigid well-defined leak rates when they are to be installed in a nuclear facility. This paper describes two implementations of an instrumentation system that is used to test leak rates on heating, ventilation, and air conditioning (HVAC) plenums, gloveboxes, and experimental chambers, etc. One of the implementations used a programmable logic controller (PLC). The other used what is probably a simpler system based on FlexNet{reg_sign} modules. The emphasis on both systems was on automatic data collection, automatic report generation, and validation of the test results to ERDA 76-21 and ASME-N510. The data are collected using input modules connected to the PLC in one case. In the other case the data are collected using the FlexNet{reg_sign} modules. In both cases, the data are stored and the reports are generated in a spreadsheet.

  16. Gels, monomer solutions fix pinhole casing leaks

    SciTech Connect

    Creel, P.; Crook, R.

    1997-10-13

    Sodium silicate gel and in situ polymerizing monomer (IPM) solutions have had nearly 100% success in repairing pinhole casing leaks. These methods are an alternative to small-particle cement squeeze jobs and can be used in both producing and injection wells. The particles in small-particle or fine-grind cement average 5 microns in diameter compared to the 50 micron particles in Portland cement. Repairs not only help satisfy regulatory requirements but also reduce possible related casing repair costs such as during drillouts, repeated cement squeezes, and workovers. If casing leaks in injection wells are unsuccessfully squeezed and fail regulatory testing, the operator may be fined and the wells may have to be plugged and abandoned. The paper describes the repair of both injection and production well casings.

  17. Hydrogen leak detection in the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Barile, Ronald G

    1992-01-01

    This study focuses on a helium gas jet flowing into room air. Measurements of helium concentration and velocity in the jet-air mixture are reported. The objective is to learn about jet characteristics so that dynamically similar hydrogen leaks may be located in the Space Shuttle. The hazardous gas detection system (HGDS) in the mobile launch pad uses mass spectrometers to monitor the shuttle environment for leaks. The mass spectrometers are fed by long sample tubes which draw gas from the payload bay, mid body, aft engine compartment and external tank. The overall purpose of this study is to improve the HGDS especially in its potential for locating hydrogen leaks. A rapid-response leak detection experiment was designed, built, and tested, following on the work done in this program last summer. The apparatus included a Perkin Elmer MGA-1200 mass spectrometer and air velocity transducer, both monitored by a Macintosh IIFX computer using LabVIEW software. A jet of helium flowing into the lab air simulated a gas leak. Steady helium or hydrogen-nitrogen jets were logged for concentration and velocity, and the power spectral density of each was computed. Last year, large eddies and vortices were visually seen with Schlieren imaging, and they were detected in the time plots of the various instruments. The response time of the MGA-1200 was found in the range of 0.05 to 0.1 sec. Pulsed concentration waves were clearly detected at 25 cycles per sec by spectral analysis of MGA data. No peaks were detected in the power spectrum, so in the present study, 10 Hz bandwidth-averaged power levels were examined at regular frequency intervals. The practical consequences of last year's study are as follows: sampling frequency should be increased above the present rate of 1 sample per second so that transients could be observed and analyzed with frequency response methods. Many more experiments and conditions were observed in this second summer, including the effects of orifice diameter

  18. Scintigraphy for Pulmonary Capillary Protein Leak

    DTIC Science & Technology

    1982-09-01

    adrministration (16). The method is noninvasive and has been used clinically to determine the severity and duration of non- cardiogenic pulmonary edema ...If the leak exceeds the 1.iiiphatic capacity, which can increase flow by a factor of 20, pulmcnary interstitial edema occurs. T•hen the interstitial...of shoee is the accepted !::odel for the scudv of pulmonary permehbility - edema (18). It is, therefore, necessary to comnpare our scintigraphic

  19. Scintigraphy for Pulmonary Capillary Protein Leak

    DTIC Science & Technology

    1983-09-01

    det,,rmine the severity and duration of non- cardiogenic pulmonary edema (17). C. Approach to the Problem The anim-als were anesthetize,, intubated and...pulmonary lymphatics. If the leak exceeds the lymphatic capacity, which can increase flow by a factor of 20, pulmonary interstitial edema occurs. When...therefore, does not appear to cause permeability pulmonary edema in either the sheep or dog. The ARDS seen in patients following sclerotherapy of esophageal

  20. Natural gas pipeline leaks across Washington, DC.

    PubMed

    Jackson, Robert B; Down, Adrian; Phillips, Nathan G; Ackley, Robert C; Cook, Charles W; Plata, Desiree L; Zhao, Kaiguang

    2014-01-01

    Pipeline safety in the United States has increased in recent decades, but incidents involving natural gas pipelines still cause an average of 17 fatalities and $133 M in property damage annually. Natural gas leaks are also the largest anthropogenic source of the greenhouse gas methane (CH4) in the U.S. To reduce pipeline leakage and increase consumer safety, we deployed a Picarro G2301 Cavity Ring-Down Spectrometer in a car, mapping 5893 natural gas leaks (2.5 to 88.6 ppm CH4) across 1500 road miles of Washington, DC. The δ(13)C-isotopic signatures of the methane (-38.2‰ ± 3.9‰ s.d.) and ethane (-36.5 ± 1.1 s.d.) and the CH4:C2H6 ratios (25.5 ± 8.9 s.d.) closely matched the pipeline gas (-39.0‰ and -36.2‰ for methane and ethane; 19.0 for CH4/C2H6). Emissions from four street leaks ranged from 9200 to 38,200 L CH4 day(-1) each, comparable to natural gas used by 1.7 to 7.0 homes, respectively. At 19 tested locations, 12 potentially explosive (Grade 1) methane concentrations of 50,000 to 500,000 ppm were detected in manholes. Financial incentives and targeted programs among companies, public utility commissions, and scientists to reduce leaks and replace old cast-iron pipes will improve consumer safety and air quality, save money, and lower greenhouse gas emissions.

  1. Probabilistic pipe fracture evaluations for leak-rate-detection applications

    SciTech Connect

    Rahman, S.; Ghadiali, N.; Paul, D.; Wilkowski, G.

    1995-04-01

    Regulatory Guide 1.45, {open_quotes}Reactor Coolant Pressure Boundary Leakage Detection Systems,{close_quotes} was published by the U.S. Nuclear Regulatory Commission (NRC) in May 1973, and provides guidance on leak detection methods and system requirements for Light Water Reactors. Additionally, leak detection limits are specified in plant Technical Specifications and are different for Boiling Water Reactors (BWRs) and Pressurized Water Reactors (PWRs). These leak detection limits are also used in leak-before-break evaluations performed in accordance with Draft Standard Review Plan, Section 3.6.3, {open_quotes}Leak Before Break Evaluation Procedures{close_quotes} where a margin of 10 on the leak detection limit is used in determining the crack size considered in subsequent fracture analyses. This study was requested by the NRC to: (1) evaluate the conditional failure probability for BWR and PWR piping for pipes that were leaking at the allowable leak detection limit, and (2) evaluate the margin of 10 to determine if it was unnecessarily large. A probabilistic approach was undertaken to conduct fracture evaluations of circumferentially cracked pipes for leak-rate-detection applications. Sixteen nuclear piping systems in BWR and PWR plants were analyzed to evaluate conditional failure probability and effects of crack-morphology variability on the current margins used in leak rate detection for leak-before-break.

  2. DETECTION OF INTERSTATE LIQUIDS PIPELINE LEAKS: FEASIBILITY EVALUATION.

    SciTech Connect

    DIETZ,R.N.

    1998-10-20

    The approximately 200,000-mile fuel pipeline system in the U.S. operates at flow rates up to 2.5 x 10{sup 6}gallons per hour (GPH). Most commercial technologies only provide on-line leak detection at about 0.3% of flow rate, i.e., about 7,500 GPH or larger. Detection of leaks at about 1 GPH or so is desirable both from a regulatory and leak-prevention standpoint. Brookhaven's commercially-accepted perfluorocarbon tracer (PFT) technology for underground leak detection of utility industry dielectric fluids at leak rates less than 0.1 GPH, with new enhancements, will be able to cost-effectively detect fuel pipeline system leaks to about 1 GPH--3 orders-of-magnitude better than any on-line system. The magnitude of detected leaks would be calculable as well. Proposed mobile surveys (such as those used periodically in the gas pipeline industry) at about 110 to 120 miles per day would allow such small leaks to be detected at 10-ppb tagging levels (less than $1,500 of PFT for a 48-hour tag at the maximum transport rate) under worst-case meteorological dispersion conditions. Smaller leaks could be detected by proportionately larger tagging concentrations. Leaks would be pinpointed by subsequent conventional barholing and vapor analyses. There are no health nor safety issues associated with the use of the proposed technological approach nor any consequential environmental impacts associated with the proposed magnitudes of PFT tagging.

  3. Detection of interstate liquids pipeline leaks: Feasibility evaluation

    SciTech Connect

    Dietz, R.N.; Senum, G.I.

    1998-10-20

    The approximately 200,000-mile fuel pipeline system in the US operates at flow rates up to 2.5 {times} 10{sup 6} gallons per hour (GPH). Most commercial technologies only provide on-line leak detection at about 0.3% of flow rate, i.e., about 7,500 GPH or larger. Detection of leaks at about 1 GPH or so is desirable both from a regulatory and leak-prevention standpoint. Brookhaven`s commercially-accepted perfluorocarbon tracer (PFT) technology for underground leak detection of utility industry dielectric fluids at leak rates less than 0.1 GPH, with new enhancements, will be able to cost-effectively detect fuel pipeline system leaks to about 1 GPH--3 orders-of-magnitude better than any on-line system. The magnitude of detected leaks would be calculable as well. Proposed mobile surveys (such as those used periodically in the gas pipeline industry) at about 110 to 120 miles per day would allow such small leaks to be detected at 10-ppb tagging levels (less than $1,500 of PFT for a 48-hour tag at the maximum transport rate) under worst-case meteorological dispersion conditions. Smaller leaks could be detected by proportionately larger tagging concentrations. Leaks would be pinpointed by subsequent conventional barholing and vapor analyses. There are no health nor safety issues associated with the use of the proposed technological approach nor any consequential environmental impacts associated with the proposed magnitudes of PFT tagging.

  4. Use of IHTS pipe leak jacketing for LSPB

    SciTech Connect

    1983-08-15

    In an effort to reduce costs of the Large Scale Prototype Breeder (LSPB), Westinghouse and Burns and Roe examined the use of leak jacketing the Intermediate Heat Transport System (IHTS) piping in the Steam Generation Building (SGB) to reduce the amount of sodium leaked to the SGB atmosphere. The design basis leak for the LSPB, IHTS, is an Moderate Energy Fluid System (MEFS) leak. Previous calculations performed for the Mainstream Design SGB showed that high pressures, temperature and hydrogen concentrations would be produced as a result of the sodium leak. The high pressures would mean that the SGB would have to be vented to avoid overpressurization. Venting the SGB results in the dispersion of large quantities of sodium aerosols which can be ingested into reactor or spent fuel decay heat removal heat exchangers, the control room HVAC or the emergency gas turbines. This would require expensive design changes or relocating plant safety related equipment. By leak jacketing the IHTS piping, the effects of the sodium leak in the SGB can be greatly reduced. As a result of this study, it is recommended that leak jacketing of the large diameter IHTS piping in the SGB be used in the design of LSPB. The leak jacketing concept was the most cost effective means of mitigating the consequences of an MEFS leak in the SGB. This report shows the basis and results of the anaylsis, mitigation features and costs, and conclusions.

  5. LEAK: A source term generator for evaluating release rates from leaking vessels

    SciTech Connect

    Clinton, J.H.

    1994-09-01

    An interactive computer code for estimating the rate of release of any one of several materials from a leaking tank or broken pipe leading from a tank is presented. It is generally assumed that the material in the tank is liquid. Materials included in the data base are acetonitrile, ammonia, carbon tetrachloride, chlorine, chlorine trifluoride, fluorine, hydrogen fluoride, nitric acid, nitrogen tetroxide, sodium hydroxide, sulfur hexafluoride, sulfuric acid, and uranium hexafluoride. Materials that exist only as liquid and/or vapor over expected ranges of temperature and pressure can easily be added to the data base file. The Fortran source code for LEAK and the data file are included with this report.

  6. One-Piece Leak-Proof Battery

    DOEpatents

    Verhoog, Roelof

    1999-03-23

    The casing of a leak-proof one-piece battery is made of a material comprising a mixture of at least a matrix based on polypropylene and an alloy of a polyamide and a polypropylene. The ratio of the matrix to the alloy is in the range 0.5 to 6 by weight. The alloy forms elongate arborescent inclusions in the matrix such that, on average, the largest dimension of a segment of the arborescence is at least twenty times the smallest dimension of the segment.

  7. Low heat-leak cryogenic envelope

    DOEpatents

    DeHaan, James R.

    1976-10-19

    A plurality of cryogenic envelope sections are joined together to form a power transmission line. Each of the sections is comprised of inner and outer tubes having multilayer metalized plastic spirally wrapped within a vacuum chamber formed between the inner and outer tubes. A refrigeration tube traverses the vacuum chamber, but exits one section and enters another through thermal standoffs for reducing heat-leak from the outer tube to the refrigeration tube. The refrigeration tube passes through a spirally wrapped shield within each section's vacuum chamber in a manner so that the refrigeration tube is in close thermal contact with the shield, but is nevertheless slideable with respect thereto.

  8. A Hydrogen Leak Detection System for Aerospace and Commercial Applications

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.; Makel, D. B.; Jansa, E. D.; Patterson, G.; Cova, P. J.; Liu, C. C.; Wu, Q. H.; Powers, W. T.

    1995-01-01

    Leaks on the space shuttle while on the launch pad have generated interest in hydrogen leak monitoring technology. Microfabricated hydrogen sensors are being fabricated at Case Western Reserve University (CWRU) and tested at NASA Lewis Research Center (LeRC). These sensors have been integrated into hardware and software designed by Aerojet. This complete system allows for multipoint leak monitoring designed to provide leak source and magnitude information in real time. The monitoring system processes data from the hydrogen sensors and presents the operator with a visual indication of the leak location and magnitude. Although the leak monitoring system was designed for hydrogen propulsion systems, the possible applications of this monitoring system are wide ranged. This system is in operation in an automotive application which requires high sensitivity to hydrogen.

  9. A hydrogen leak detection system for aerospace and commercial applications

    NASA Astrophysics Data System (ADS)

    Hunter, Gary W.; Makel, D. B.; Jansa, E. D.; Patterson, G.; Cova, P. J.; Liu, C. C.; Wu, Q. H.; Powers, W. T.

    1995-10-01

    Leaks on the space shuttle while on the launch pad have generated interest in hydrogen leak monitoring technology. Microfabricated hydrogen sensors are being fabricated at Case Western Reserve University (CWRU) and tested at NASA Lewis Research Center (LeRC). These sensors have been integrated into hardware and software designed by Aerojet. This complete system allows for multipoint leak monitoring designed to provide leak source and magnitude information in real time. The monitoring system processes data from the hydrogen sensors and presents the operator with a visual indication of the leak location and magnitude. Although the leak monitoring system was designed for hydrogen propulsion systems, the possible applications of this monitoring system are wide ranged. This system is in operation in an automotive application which requires high sensitivity to hydrogen.

  10. [Leak test for the internal circuit of anesthesia machines].

    PubMed

    Tokumine, J; Iha, H; Okuda, Y

    1999-05-01

    In spite of detailed periodic inspection performed by specialized engineers, a great number of anesthesia machines fail to meet the standard of low flow leak test because of leak in the internal circuit. To find out the background and the solution to the problem, we sent questionnaire to 11 major manufacturers and/or dealers each responsible for periodic inspection of anesthetic machines. According to the responses to the questionnaire, the manufacturers and/or the dealers had various methods of internal circuit leak test without a unified standard in detail. The mismatch of the test methods with those anesthesia machines equipped with check valve mechanism has also led to poor evaluation of internal circuit leak. Leak test must be standardized for its appropriate application to work effectively for the problem of leak in the internal circuit of anesthesia machines.

  11. Long-life leak standard assembly. [Patent application

    DOEpatents

    Basford, J.A.; Mathis, J.E.; Wright, H.C.

    1980-11-12

    The present invention is directed to a portable leak standard assembly which is capable of providing a stream of high-purity reference gas at a virtually constant flow rate over an extensive period of time. The leak assembly comprises a high pressure reservoir coupled to a metal leak valve through a valve-controlled conduit. A reproducible leak valve useful in this assembly is provided by a metal tube crimped with a selected pressure loading for forming an orifice in the tube with this orifice being of a sufficient size to provide the selected flow rate. The leak valve assembly is formed of metal so that it can be baked-out in a vacuum furnace to rid the reservoir and attendent components of volatile impurities which reduce the efficiency of the leak standard.

  12. EPA Chases Leaks in New Mexico during Seventh Annual Fix a Leak Week

    EPA Pesticide Factsheets

    DALLAS - (March 16, 2015) Dripping faucets and leaky toilets account for a large portion of home water waste. Every year, more than 10,000 gallons of water is wasted in homes due to easy-to-fix leaks. The U.S. Environmental Protection Agency (EPA) i

  13. Leak locating microphone, method and system for locating fluid leaks in pipes

    DOEpatents

    Kupperman, David S.; Spevak, Lev

    1994-01-01

    A leak detecting microphone inserted directly into fluid within a pipe includes a housing having a first end being inserted within the pipe and a second opposed end extending outside the pipe. A diaphragm is mounted within the first housing end and an acoustic transducer is coupled to the diaphragm for converting acoustical signals to electrical signals. A plurality of apertures are provided in the housing first end, the apertures located both above and below the diaphragm, whereby to equalize fluid pressure on either side of the diaphragm. A leak locating system and method are provided for locating fluid leaks within a pipe. A first microphone is installed within fluid in the pipe at a first selected location and sound is detected at the first location. A second microphone is installed within fluid in the pipe at a second selected location and sound is detected at the second location. A cross-correlation is identified between the detected sound at the first and second locations for identifying a leak location.

  14. The regulation and physiology of mitochondrial proton leak.

    PubMed

    Divakaruni, Ajit S; Brand, Martin D

    2011-06-01

    Mitochondria couple respiration to ATP synthesis through an electrochemical proton gradient. Proton leak across the inner membrane allows adjustment of the coupling efficiency. The aim of this review is threefold: 1) introduce the unfamiliar reader to proton leak and its physiological significance, 2) review the role and regulation of uncoupling proteins, and 3) outline the prospects of proton leak as an avenue to treat obesity, diabetes, and age-related disease.

  15. Lymphangiography in the Diagnosis and Localization of Various Chyle Leaks

    SciTech Connect

    Deso, Steve; Ludwig, Benjamin; Kabutey, Nii-Kabu; Kim, Ducksoo; Guermazi, Ali

    2012-02-15

    Purpose: Chyle leaks are rare entities infrequently encountered by most physicians. However, large centers providing advanced surgical care are inevitably confronted with chyle leaks as a complication of surgery, an extension of disease, or as a primary disorder. Regardless of the etiology, proper diagnosis and localization are paramount in the management of any chyle leak. Materials and Methods: Here we present 16 patients with 17 chyle leaks (5 chyluria, 8 chylothorax, and 4 chylous ascites) who underwent bipedal lymphangiography (LAG) and postprocedure computed tomography (CT) imaging. Results: In each case, the source of the chyle leak was identified and properly localized to guide further treatment. Of the 16 patients who underwent LAG and postprocedure CT imaging, the initial LAG alone provided the diagnosis and localized the chyle leak in 4 patients (25%); the postprocedure CT imaging provided the diagnosis and localized the chyle leak in 6 patients (37.5%); and the two modalities were equal in the diagnosing and localizing the chyle leak in the remaining 6 patients (37.5%)ConclusionThese cases highlight the unparalleled abilities of LAG and the added benefit of post-LAG CT imaging in the diagnosis and fine anatomic localization of chyle leaks. In addition, these cases demonstrate the retained utility of LAG in these investigations despite the development of alternative tests involving CT, magnetic resonance imaging, and nuclear medicine imaging.

  16. Margins in high temperature leak-before-break assessments

    SciTech Connect

    Budden, P.J.; Hooton, D.G.

    1997-04-01

    Developments in the defect assessment procedure R6 to include high-temperature mechanisms in Leak-before-Break arguments are described. In particular, the effect of creep on the time available to detect a leak and on the crack opening area, and hence leak rate, is discussed. The competing influence of these two effects is emphasized by an example. The application to Leak-before-Break of the time-dependent failure assessment diagram approach for high temperature defect assessment is then outlined. The approach is shown to be of use in assessing the erosion of margins by creep.

  17. Method to control the amount of helium during leak testing

    SciTech Connect

    Frank E. Jurvic, Jr.

    2002-03-29

    The purpose of this paper is to demonstrate a method for limiting the amount of helium administered during leak testing and provide a method for keeping the atmospheric helium in a location to a minimum to eliminate backstreaming into the system. This method utilizes the permeability of a balloon. The transporting of helium to the leak check area is also safer by not requiring a cylinder in the leak check location. Utilizing the many shapes of balloons and partially filling of the balloon, any configuration can deliver helium to the leak location. The balloon I filled for the test fell to the floor with the amount of helium I put into the balloon.

  18. Comprehensive leak detection survey and benefit/cost analysis

    SciTech Connect

    Scholze, R.J. Jr.; Maloney, S.W.

    1995-06-01

    Fort Carson, Colorado was the site of a comprehensive leak detection investigation of the potable water system with the express purpose of quantifying the benefits to be derived by a military installation from use of leak detection and repair technology. Military bases are often the size of a small city and one Directorate or Department has responsibility for all real estate (buildings, roads, grounds, etc.) unlike a municipal public works department. The investigation used state of the art noise correlation and computer correlation technology to survey the distribution system mains. This was complemented by a building to building survey covering office and commercial buildings along with family and barracks housing where investigators entered buildings and quantified visible leaks in faucets and water closets, etc. Following repairs and a year`s time, a follow-on survey is performed to again examine all aspects of the system. The result was a complete economic evaluation and benefit/cost analysis of the installation. Representative findings include: the majority of distribution system leaks were at hydrants or similar appurtenances; and family housing was found to be the other major concentration of leaks. However, where the first survey found 80 percent of housing units had leaks, findings from the second round on the order of 20 percent. Office buildings were found from the first survey to not merit follow-on attention due to limited numbers of leaks. Water-consciousness was raised for both the responsible directorate and individuals in family housing and leak repair was given a higher priority for repairs. This paper will outline the leak detection methodology used, characterize the types and patterns of leaks found, introduce an economic analysis for the entire leak detection process, and finally, provide lessons learned with practical results and implications.

  19. Argon Spill Trough Bellows - Leak Test

    SciTech Connect

    Jaques, A.; /Fermilab

    1990-04-30

    The four argon spill trough bellows were leak tested with helium during the week of March 12, 1990. Three passed without incident, but the fourth was found to have a leak in the weld at one of the ring/clamps. The hole was approximately 1/32-inch in diameter (a likely result of a welding burn through) and located on an inflexible portion of the bellows, the ring/clamp. Frank Juravic, who conducted the tests, suggested using grey structural epoxy to plug the leak. The epoxy is metallic with some inherent flexibility. The epoxy was applied and the bellows retested in the same manner as before. The repair was a success as the bellows proved to be leaktight. The bellows were then put in their original shipping crates and placed in storage at Lab C. Included in this report is the manufacturer's spec sheets on the bellows, a copy of the Quality Control Report form and a sketch of the test setup with an explanation of the procedure. On the bellows data sheet entitled 'Analysis of Stress in Bellows', the analysis output is obtained through a theoretical bellows program that uses quadratic equations to approximate characteristic curves for such data as axial, lateral and angular movement and spring rates. The program is best suited for bellows with a wall thickness of at least 0.015-inch and an operating pressure significantly above atmospheric. Thus EJS Inc. warned that the output data would not be very accurate in some instances. The data given on the EJS Inc. sketch sheet should be taken as accurate, though, for it was taken from the actual bellows delivered. The 72-inch length includes the 64.64-inch of bellows section, the (3) 1/2-inch ring/clamps and the (2) 1-1/2-inch end bands. The remainder of the discrepancy is accounted for by a 2.75-inch factory elongation of the bellows from the original free length. The 40-inch compression capability includes the 2.75-inch of factory elongation, the program determined 31.9-inch of compression from free length and 5.35-inch of

  20. Pressure Change Measurement Leak Testing Errors

    SciTech Connect

    Pryor, Jeff M; Walker, William C

    2014-01-01

    A pressure change test is a common leak testing method used in construction and Non-Destructive Examination (NDE). The test is known as being a fast, simple, and easy to apply evaluation method. While this method may be fairly quick to conduct and require simple instrumentation, the engineering behind this type of test is more complex than is apparent on the surface. This paper intends to discuss some of the more common errors made during the application of a pressure change test and give the test engineer insight into how to correctly compensate for these factors. The principals discussed here apply to ideal gases such as air or other monoatomic or diatomic gasses; however these same principals can be applied to polyatomic gasses or liquid flow rate with altered formula specific to those types of tests using the same methodology.

  1. Silver plating technique seals leaks in thin wall tubing joints

    NASA Technical Reports Server (NTRS)

    Blenderman, W. H.

    1966-01-01

    Leaks in thin wall tubing joints are sealed by cleaning and silver plating the hot gas side of the joint in the leakage area. The pressure differential across the silver during hydrostatic test and subsequent use forces the ductile silver into the leak area and seals it.

  2. 10 CFR 39.35 - Leak testing of sealed sources.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.35 Leak testing of sealed sources. (a) Testing and recordkeeping requirements. Each licensee who uses... requirements. The following sealed sources are exempt from the periodic leak test requirements set out...

  3. 10 CFR 39.35 - Leak testing of sealed sources.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.35 Leak testing of sealed sources. (a) Testing and recordkeeping requirements. Each licensee who uses... requirements. The following sealed sources are exempt from the periodic leak test requirements set out...

  4. 10 CFR 39.35 - Leak testing of sealed sources.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.35 Leak testing of sealed sources. (a) Testing and recordkeeping requirements. Each licensee who uses... requirements. The following sealed sources are exempt from the periodic leak test requirements set out...

  5. 40 CFR 63.424 - Standards: Equipment leaks.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Standards: Equipment leaks. 63.424 Section 63.424 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS....424 Standards: Equipment leaks. (a) Each owner or operator of a bulk gasoline terminal or...

  6. 40 CFR 1065.644 - Vacuum-decay leak rate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Vacuum-decay leak rate. 1065.644 Section 1065.644 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.644 Vacuum-decay leak...

  7. 40 CFR 1065.644 - Vacuum-decay leak rate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Vacuum-decay leak rate. 1065.644 Section 1065.644 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.644 Vacuum-decay leak...

  8. 40 CFR 1065.644 - Vacuum-decay leak rate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Vacuum-decay leak rate. 1065.644 Section 1065.644 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.644 Vacuum-decay leak...

  9. 40 CFR 1065.644 - Vacuum-decay leak rate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Vacuum-decay leak rate. 1065.644 Section 1065.644 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.644 Vacuum-decay leak...

  10. 40 CFR 1065.644 - Vacuum-decay leak rate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Vacuum-decay leak rate. 1065.644 Section 1065.644 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.644 Vacuum-decay leak...

  11. 241-AY-102 Leak Detection Pit Drain Line Inspection Report

    SciTech Connect

    Boomer, Kayle D.; Engeman, Jason K.; Gunter, Jason R.; Joslyn, Cameron C.; Vazquez, Brandon J.; Venetz, Theodore J.; Garfield, John S.

    2014-01-20

    This document provides a description of the design components, operational approach, and results from the Tank AY-102 leak detection pit drain piping visual inspection. To perform this inspection a custom robotic crawler with a deployment device was designed, built, and operated by IHI Southwest Technologies, Inc. for WRPS to inspect the 6-inch leak detection pit drain line.

  12. HIGH RESOLUTION RESISTIVITY LEAK DETECTION DATA PROCESSING & EVALUATION MEHTODS & REQUIREMENTS

    SciTech Connect

    SCHOFIELD JS

    2007-10-04

    This document has two purposes: {sm_bullet} Describe how data generated by High Resolution REsistivity (HRR) leak detection (LD) systems deployed during single-shell tank (SST) waste retrieval operations are processed and evaluated. {sm_bullet} Provide the basic review requirements for HRR data when Hrr is deployed as a leak detection method during SST waste retrievals.

  13. 40 CFR 63.1255 - Standards: Equipment leaks.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... leaking connectors in the group of processes was less than 0.5 percent, but equal to or greater than 0.25... of processes was less than 0.25 percent during the initial or last required monitoring period. An... quarters. (v) For a group of processes with less than 0.25 percent leaking valves, the owner or...

  14. 40 CFR 63.1255 - Standards: Equipment leaks.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... leaking connectors in the group of processes was less than 0.5 percent, but equal to or greater than 0.25... of processes was less than 0.25 percent during the initial or last required monitoring period. An... quarters. (v) For a group of processes with less than 0.25 percent leaking valves, the owner or...

  15. 40 CFR 63.1363 - Standards for equipment leaks.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... percent, but equal to or greater than 0.25 percent, during the last required monitoring period, monitoring... leaking connectors in the group of process units was less than 0.25 percent during the last required... once every 4 quarters. (v) For a group of processes with less than 0.25 percent leaking valves,...

  16. 40 CFR 63.1255 - Standards: Equipment leaks.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... leaking connectors in the group of processes was less than 0.5 percent, but equal to or greater than 0.25... of processes was less than 0.25 percent during the initial or last required monitoring period. An... quarters. (v) For a group of processes with less than 0.25 percent leaking valves, the owner or...

  17. 40 CFR 63.1363 - Standards for equipment leaks.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... percent, but equal to or greater than 0.25 percent, during the last required monitoring period, monitoring... leaking connectors in the group of process units was less than 0.25 percent during the last required... once every 4 quarters. (v) For a group of processes with less than 0.25 percent leaking valves,...

  18. 40 CFR 63.1363 - Standards for equipment leaks.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... percent, but equal to or greater than 0.25 percent, during the last required monitoring period, monitoring... leaking connectors in the group of process units was less than 0.25 percent during the last required... once every 4 quarters. (v) For a group of processes with less than 0.25 percent leaking valves,...

  19. [Paravalvular leak following surgical valve replacement: is there a role for percutaneous paravalvular leak reduction?].

    PubMed

    Noble, S; lbrahim, R; Basmadjian, A; Müller, H; Lerch, R; Roffi, M

    2010-06-02

    After valve replacement, significant paravalvular leaks (PVL) may develop in up to 12.5% of the cases. Signs and symptoms include congestive heart failure and/or haemolysis and therefore may require reintervention. Redo valve surgery is considered the therapy of choice for symptomatic patients, either by valve replacement or leak repair. Considering the risk of morbidity and mortality associated with a surgical reintervention and the high post-surgical recurrence of PVL, the endovascular treatment represents an attractive alternative to surgery for high risk patients. The percutaneous approach aims at PVL reduction by implantation of certain occluder devices. The procedure is technically feasible in 60 to 90% of the cases according to different series. Technical success is associated with clinical improvement in 50 to 80% of the cases.

  20. Effect of leak location on measured respirator fit.

    PubMed

    Crutchfield, C D; Park, D L

    1997-06-01

    A significant difference in leak detection as a function of leak location was observed during a study assessing how well current models of quantitative fit-test systems detect leakage. Known sources of leakage (matched hypodermic needles) were introduced at three fixed locations into factory-probed half-mask and full-face respirators mounted on a headform-breathing machine system. The leak locations were the bridge of the nose, the cheek, and the chin. Baseline leakage into each respirator was determined by conducting a fit-test with all fixed leak sources capped. Fit tests were repeated with each individual source uncapped. Study objectives included determining (1) how well each system measured the leakage, and (2) whether leak location had any effect on leak measurement. An ambient aerosol fit-test system (Portacount Plus) and a controlled negative pressure (CNP) fit-test system (FitTester 3000) were used. The ambient aerosol system detected an overall average of 37.2% of the known leakage, with a coefficient of variation of 44.7%. An analysis of variance showed significant differences in aerosol system measurements of leakage as a function of leak location and mask type (p < 0.001). A different pattern of aerosol leak detection as a function of leak location was observed between half-mask and full-face respirators, which appears to be related to differences in in-mask airflow dynamics. The CNP system detected an overall average of 97.9% of the known leakage through the same hypodermic needles, with a coefficient of variation of 4.3%. CNP system results were not affected by leak location (p > 0.43) or mask type (p > 0.32).

  1. Management of CSF Leaks Following Vestibular Schwannoma Surgery

    PubMed Central

    Mangus, Brannon D.; Rivas, Alejandro; Yoo, Mi Jin; Alvarez, JoAnn; Wanna, George B.; Haynes, David S.; Bennett, Marc L.

    2011-01-01

    Objective To evaluate the incidence and treatment of CSF leaks after resection of vestibular schwannomas and to propose a treatment algorithm for their management. Study Design Retrospective chart review. Setting Tertiary referral center. Patients Review of 1,922 subjects who underwent resection of vestibular schwannomas from 1970 through 2010. Intervention Surgical resection of vestibular schwannoma. Main Outcome Measures Patient demographics, surgical approach used, CSF leak incidence, meningitis, treatment and success in the management of CSF leaks. Results Postoperative CSF leaks were observed in 12.9% of our patients. There was no significant difference between the type of approach and the presence of CSF leak with translabyrinthine, suboccipital and middle fossa CSF leak rates of 12%, 12%, and 13% respectively (p=0.07). Patients presented with a wound leak or rhinorrhea almost equally. Ultimately, 92% of patients with rhinorrhea underwent surgical intervention. The probability of a patient with rhinorrhea requiring a second intervention was higher when the initial intervention was conservative rather than surgical. However, the probability of a patient with a wound leak requiring a second intervention was essentially the same when initially treated conservatively or surgically. Conclusion Our data suggests that there is no difference in CSF leak rates between the different surgical approaches. The appropriate treatment strategy is dependent on the presentation of the CSF. While conservative treatment is effective for managing wound leaks, it is less effective in managing patients with rhinorrhea. Therefore, surgical treatments should play an early role in the treatment algorithm of patients with CSF rhinorrhea. PMID:21970847

  2. Intelligence Leaks: What Is the Role of the Leak and the Leaker in U.S. Democracy?

    DTIC Science & Technology

    2014-03-01

    between the Pentagon Papers and WikiLeaks to Edward Snowden. 14. SUBJECT TERMS Bradley Manning, Daniel Ellsberg, executive...35 1. Background ........................................................................................36 2. Bradley Manning... Bradley Manning provided thousands of secret government documents to WikiLeaks—to date the largest leak of classified documents in U.S. history.3 His

  3. Leak testing of cryogenic components — problems and solutions

    NASA Astrophysics Data System (ADS)

    Srivastava, S. P.; Pandarkar, S. P.; Unni, T. G.; Sinha, A. K.; Mahajan, K.; Suthar, R. L.

    2008-05-01

    A prototype of Cold Neutron Source (CNS) for Dhruva Reactor is being manufactured at Centre for Design and Manufacture (CDM), BARC, Mumbai for validating the mechanical and thermal engineering design aspects, besides checking the integrity of all joints and components at low temperature, 77K. Task of a Cold Neutron Source is to generate cold neutrons by cooling down the thermal neutrons, which are originally produced in a nuclear research reactor. The complete Cold Neutron Source system comprises a complex arrangement of moderator pot, transfer line (piping), pumps, refrigerators, storage tanks, a heat exchanger and associated controls and instrumentation. The heart of the system is moderator pot in which water (moderator) is cooled down by Liquid Nitrogen (LN2) being circulated through an annular cavity machined on the walls of the pot. Transfer lines for LN2 basically consist of two concentric Stainless Steel flexible pipes, which are joined to the inlet and outlet Aluminium tubes of the moderator pot through transition joints. Leak in any component may result in loss of liquid Nitrogen, degradation of vacuum, which in turn may affect the heat removal efficiency of the source. Hence, leak testing was considered a very important quality control tool and all joints and components were subjected to helium leak test using mass spectrometer leak detector (MSLD) at cryogenic temperature. During one of the earlier experiments, flow of LN2 through inner flexible pipe of the transfer line resulted in rise of pressure in the vacuum annulus and sweating on the outer flexible pipe. After investigations it was found that large thermal stress compounded with mechanical stress resulted in cracks in the inner pipe. Accordingly design was modified to get leak proof transfer line assembly. Further, during leak testing of thin wall moderator pot, gross leak was observed on the outer jacket welded joint. Leak was so large that even a small amount of Helium gas in the vicinity of the

  4. ISS Ammonia Leak Detection Through X-Ray Fluorescence

    NASA Technical Reports Server (NTRS)

    Camp, Jordan; Barthelmy, Scott; Skinner, Gerry

    2013-01-01

    Ammonia leaks are a significant concern for the International Space Station (ISS). The ISS has external transport lines that direct liquid ammonia to radiator panels where the ammonia is cooled and then brought back to thermal control units. These transport lines and radiator panels are subject to stress from micrometeorites and temperature variations, and have developed small leaks. The ISS can accommodate these leaks at their present rate, but if the rate increased by a factor of ten, it could potentially deplete the ammonia supply and impact the proper functioning of the ISS thermal control system, causing a serious safety risk. A proposed ISS astrophysics instrument, the Lobster X-Ray Monitor, can be used to detect and localize ISS ammonia leaks. Based on the optical design of the eye of its namesake crustacean, the Lobster detector gives simultaneously large field of view and good position resolution. The leak detection principle is that the nitrogen in the leaking ammonia will be ionized by X-rays from the Sun, and then emit its own characteristic Xray signal. The Lobster instrument, nominally facing zenith for its astrophysics observations, can be periodically pointed towards the ISS radiator panels and some sections of the transport lines to detect and localize the characteristic X-rays from the ammonia leaks. Another possibility is to use the ISS robot arm to grab the Lobster instrument and scan it across the transport lines and radiator panels. In this case the leak detection can be made more sensitive by including a focused 100-microampere electron beam to stimulate X-ray emission from the leaking nitrogen. Laboratory studies have shown that either approach can be used to locate ammonia leaks at the level of 0.1 kg/day, a threshold rate of concern for the ISS. The Lobster instrument uses two main components: (1) a microchannel plate optic (also known as a Lobster optic) that focuses the X-rays and directs them to the focal plane, and (2) a CCD (charge

  5. Resilience to leaking--dynamic systems modeling of information security.

    PubMed

    Hamacher, Kay

    2012-01-01

    Leaking of confidential material is a major threat to information security within organizations and to society as a whole. This insight has gained traction in the political realm since the activities of Wikileaks, which hopes to attack 'unjust' systems or 'conspiracies'. Eventually, such threats to information security rely on a biologistic argument on the benefits and drawbacks that uncontrolled leaking might pose for 'just' and 'unjust' entities. Such biological metaphors are almost exclusively based on the economic advantage of participants. Here, I introduce a mathematical model of the complex dynamics implied by leaking. The complex interactions of adversaries are modeled by coupled logistic equations including network effects of econo-communication networks. The modeling shows, that there might arise situations where the leaking envisioned and encouraged by Wikileaks and the like can strengthen the defending entity (the 'conspiracy'). In particular, the only severe impact leaking can have on an organization seems to originate in the exploitation of leaks by another entity the organization competes with. Therefore, the model suggests that leaks can be used as a `tactical mean' in direct adversary relations, but do not necessarily increase public benefit and societal immunization to 'conspiracies'. Furthermore, within the model the exploitation of the (open) competition between entities seems to be a more promising approach to control malicious organizations : divide-et-impera policies triumph here.

  6. Development of perfluorocarbon tracer technology for underground leak location.

    PubMed

    Hassoun, S; McBride, T; Russell, D A

    2000-10-01

    A method has been developed for the atmospheric sampling and analysis of four perfluorocarbon tracer (PFT) compounds simultaneously at the parts per trillion (ppt) level. PFTs were pre-concentrated using adsorbent tube air sampling. Analysis was achieved by thermal desorption (TD) and gas chromatography (GC) with electron capture detection (ECD). Efficient separation of the PFTs from the other sample constituents was achieved by use of a capillary porous layer open tubular (PLOT) GC column without the need to cool the GC oven to sub-ambient temperatures using liquid coolants (M. de Bortoli and E. Pecchio, J. High Resolut. Chromatogr., 1985, 8, 422) or for a catalytic destruction step to remove interferents (T. W. D'Ottavio, R. W. Goodrich and R. N. Dietz, Environ. Sci. Technol., 1986, 20, 100). Results from test field trials with two volatile PFTs that were buried to simulate an underground leaking cable were successful. The PFTs were detected above ground level to pinpoint the leak position. The highest tracer concentrations were detected within 1 m of the simulated leak positions 2 days after tracer burial. The developed technology was applied to an oil leaking high voltage electricity cable. One PFT was added to the cable oil which enabled detection of the oil leak to within 3 m. The reported method has many advantages over currently used leak detection methods and could, in the future, be applied to the detection of underground leaks in a variety of cables and pipes.

  7. Management of low colorectal anastomotic leak: Preserving the anastomosis.

    PubMed

    Blumetti, Jennifer; Abcarian, Herand

    2015-12-27

    Anastomotic leak continues to be a dreaded complication after colorectal surgery, especially in the low colorectal or coloanal anastomosis. However, there has been no consensus on the management of the low colorectal anastomotic leak. Currently operative procedures are reserved for patients with frank purulent or feculent peritonitis and unstable vital signs, and vary from simple fecal diversion with drainage to resection of the anastomosis and closure of the rectal stump with end colostomy (Hartmann's procedure). However, if the patient is stable, and the leak is identified days or even weeks postoperatively, less aggressive therapeutic measures may result in healing of the leak and salvage of the anastomosis. Advances in diagnosis and treatment of pelvic collections with percutaneous treatments, and newer methods of endoscopic therapies for the acutely leaking anastomosis, such as use of the endosponge, stents or clips, have greatly reduced the need for surgical intervention in selected cases. Diverting ileostomy, if not already in place, may be considered to reduce fecal contamination. For subclinical leaks or those that persist after the initial surgery, endoluminal approaches such as injection of fibrin sealant, use of endoscopic clips, or transanal closure of the very low anastomosis may be utilized. These newer techniques have variable success rates and must be individualized to the patient, with the goal of treatment being restoration of gastrointestinal continuity and healing of the anastomosis. A review of the treatment of low colorectal anastomotic leaks is presented.

  8. Autogenous Metallic Pipe Leak Repair in Potable Water Systems.

    PubMed

    Tang, Min; Triantafyllidou, Simoni; Edwards, Marc A

    2015-07-21

    Copper and iron pipes have a remarkable capability for autogenous repair (self-repair) of leaks in potable water systems. Field studies revealed exemplars that metallic pipe leaks caused by nails, rocks, and erosion corrosion autogenously repaired, as confirmed in the laboratory experiments. This work demonstrated that 100% (N = 26) of 150 μm leaks contacting representative bulk potable water in copper pipes sealed autogenously via formation of corrosion precipitates at 20-40 psi, pH 3.0-11.0, and with upward and downward leak orientations. Similar leaks in carbon steel pipes at 20 psi self-repaired at pH 5.5 and 8.5, but two leaks did not self-repair permanently at pH 11.0 suggesting that water chemistry may control the durability of materials that seal the leaks and therefore the permanence of repair. Larger 400 μm holes in copper pipes had much lower (0-33%) success of self-repair at pH 3.0-11.0, whereas all 400 μm holes in carbon steel pipes at 20 psi self-repaired at pH 4.0-11.0. Pressure tests indicated that some of the repairs created at 20-40 psi ambient pressure could withstand more than 100 psi without failure. Autogenous repair has implications for understanding patterns of pipe failures, extending the lifetime of decaying infrastructure, and developing new plumbing materials.

  9. Management of low colorectal anastomotic leak: Preserving the anastomosis

    PubMed Central

    Blumetti, Jennifer; Abcarian, Herand

    2015-01-01

    Anastomotic leak continues to be a dreaded complication after colorectal surgery, especially in the low colorectal or coloanal anastomosis. However, there has been no consensus on the management of the low colorectal anastomotic leak. Currently operative procedures are reserved for patients with frank purulent or feculent peritonitis and unstable vital signs, and vary from simple fecal diversion with drainage to resection of the anastomosis and closure of the rectal stump with end colostomy (Hartmann’s procedure). However, if the patient is stable, and the leak is identified days or even weeks postoperatively, less aggressive therapeutic measures may result in healing of the leak and salvage of the anastomosis. Advances in diagnosis and treatment of pelvic collections with percutaneous treatments, and newer methods of endoscopic therapies for the acutely leaking anastomosis, such as use of the endosponge, stents or clips, have greatly reduced the need for surgical intervention in selected cases. Diverting ileostomy, if not already in place, may be considered to reduce fecal contamination. For subclinical leaks or those that persist after the initial surgery, endoluminal approaches such as injection of fibrin sealant, use of endoscopic clips, or transanal closure of the very low anastomosis may be utilized. These newer techniques have variable success rates and must be individualized to the patient, with the goal of treatment being restoration of gastrointestinal continuity and healing of the anastomosis. A review of the treatment of low colorectal anastomotic leaks is presented. PMID:26730283

  10. Modeling the Progression of Epithelial Leak Caused by Overdistension

    PubMed Central

    Hamlington, Katharine L.; Ma, Baoshun; Smith, Bradford J.; Bates, Jason H. T.

    2016-01-01

    Mechanical ventilation is necessary for treatment of the acute respiratory distress syndrome but leads to overdistension of the open regions of the lung and produces further damage. Although we know that the excessive stresses and strains disrupt the alveolar epithelium, we know little about the relationship between epithelial strain and epithelial leak. We have developed a computational model of an epithelial monolayer to simulate leak progression due to overdistension and to explain previous experimental findings in mice with ventilator-induced lung injury. We found a nonlinear threshold-type relationship between leak area and increasing stretch force. After the force required to initiate the leak was reached, the leak area increased at a constant rate with further increases in force. Furthermore, this rate was slower than the rate of increase in force, especially at end-expiration. Parameter manipulation changed only the leak-initiating force; leak area growth followed the same trend once this force was surpassed. These results suggest that there is a particular force (analogous to ventilation tidal volume) that must not be exceeded to avoid damage and that changing cell physical properties adjusts this threshold. This is relevant for the development of new ventilator strategies that avoid inducing further injury to the lung. PMID:26951764

  11. Resilience to Leaking — Dynamic Systems Modeling of Information Security

    PubMed Central

    Hamacher, Kay

    2012-01-01

    Leaking of confidential material is a major threat to information security within organizations and to society as a whole. This insight has gained traction in the political realm since the activities of Wikileaks, which hopes to attack ‘unjust’ systems or ‘conspiracies’. Eventually, such threats to information security rely on a biologistic argument on the benefits and drawbacks that uncontrolled leaking might pose for ‘just’ and ‘unjust’ entities. Such biological metaphors are almost exclusively based on the economic advantage of participants. Here, I introduce a mathematical model of the complex dynamics implied by leaking. The complex interactions of adversaries are modeled by coupled logistic equations including network effects of econo-communication networks. The modeling shows, that there might arise situations where the leaking envisioned and encouraged by Wikileaks and the like can strengthen the defending entity (the ‘conspiracy’). In particular, the only severe impact leaking can have on an organization seems to originate in the exploitation of leaks by another entity the organization competes with. Therefore, the model suggests that leaks can be used as a `tactical mean’ in direct adversary relations, but do not necessarily increase public benefit and societal immunization to ‘conspiracies’. Furthermore, within the model the exploitation of the (open) competition between entities seems to be a more promising approach to control malicious organizations : divide-et-impera policies triumph here. PMID:23227151

  12. Leak Path Development in CO2 Wells

    NASA Astrophysics Data System (ADS)

    Torsater, M.; Todorovic, J.; Opedal, N.; Lavrov, A.

    2014-12-01

    Wells have in numerous scientific works been denoted the "weak link" of safe and cost-efficient CO2 Capture and Storage (CCS). Whether they are active or abandoned, all wells are man-made intrusions into the storage reservoir with sealing abilities depending on degradable materials like steel and cement. If dense CO2 is allowed to expand (e.g. due to leakage) it will cool down its surroundings and cause strong thermal and mechanical loading on the wellbore. In addition, CO2 reacts chemically with rock, cement and steel. To ensure long-term underground containment, it is therefore necessary to study how, why, where and when leakage occurs along CO2wells. If cement bonding to rock or casing is poor, leak paths can form already during drilling and completion of the well. In the present work, we have mapped the bonding quality of cement-rock and cement-steel interfaces - and measured their resistance towards CO2 flow. This involved a large experimental matrix including different rocks, steels, cement types and well fluids. The bonding qualities were measured on composite cores using micro computed tomography (µ-CT), and CO2 was flooded through the samples to determine leakage rates. These were further compared to numerical simulations of leakage through the digitalized µ-CT core data, and CO2chemical interactions with the materials were mapped using electron microscopy. We also present a new laboratory set-up for measuring how well integrity is affected by downhole temperature variations - and we showcase some initial results. Our work concludes that leak path development in CO2 wells depends critically on the drilling fluids and presflushes/spacers chosen already during drilling and completion of a well. Fluid films residing on rock and casing surfaces strongly degrade the quality of cement bonding. The operation of the well is also important, as even slight thermal cycling (between 10°C and 95°C on casing) leads to significant de-bonding of the annular cement.

  13. Modeling and locating underground water pipe leak with microseismic data

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Liu, Jiangping; Liu, Hao; Tian, Zhijian; Cheng, Fei

    2017-01-01

    Traditional pipeline leak locating methods require that geophones have to be placed on the pipe wall. While if the exact location of the pipeline is unknown, the leaks may not be identified accurately. To solve this problem, considering the characteristics of pipeline leak, a continuous random seismic source model is proposed and geological models are established. Based on the two dimensional (2D) viscoacoustic equations and the staggered grid finite-difference (FD) algorithm, the microseismic wave field generated by a leaking pipe is modeled. Cross-correlation analysis and the simulated annealing (SA) algorithm are employed to obtain the time difference and the leak location. Analysis and discussions of the effects of number of recorded traces, survey layout, and offset and trace interval on the accuracy of the estimated location are also conducted. Simulation and data field experiment results indicate that: (1) A continuous random source can realistically represent the leak microseismic wave field in a simulation using 2D viscoacoustic equations and staggered grid FD algorithm. (2) For the leak microseismic wave field, the cross-correlation method is effective for calculating time difference of the direct wave relative to the reference trace. However, outside the refraction blind zone, accuracy of the time difference is reduced by the effects of refracted wave. (3) The SA algorithm based upon time difference, helps to identify the leak location effectively, even in the presence of noise. Estimation of the horizontal distance is more accurate than that of the depth, and the locating errors increase with increasing number of traces and offset. Moreover, in the refraction blind zone, trace interval has almost no impact on the accuracy of the location estimate. And the symmetrical array provides a higher estimate accuracy than the asymmetrical array. (4) The acquisition method of time difference based on the microseismic theory and SA algorithm has a great potential

  14. The cuff-leak test: what are we measuring?

    PubMed

    De Backer, Daniel

    2005-02-01

    Stridor is one of the most frequent causes of early extubation failure. The cuff-leak test may help to identify patients at risk to develop post-extubation laryngeal edema. However the discrimination power of the cuff-leak test is highly variable and can be use, at best, to detect patients at risk to develop edema but should not be used to postpone extubation as tracheal extubation can still be successful in many patients with a positive test. In this editorial, the author discuss the factors influencing the leak and hence its predictive value.

  15. Quartz enhanced photoacoustic leak sensor for mechatronic components

    NASA Astrophysics Data System (ADS)

    Sampaolo, A.; Patimisco, P.; Giglio, M.; Calabrese, P. P.; Chieco, L.; Scamarcio, G.; Tittel, F. K.; Spagnolo, V.

    2016-02-01

    We report the first demonstration of a leak sensor based on a mid-IR quartz-enhanced photoacoustic (QEPAS) spectroscopic technique. A QEPAS sensor was integrated in a vacuum seal test station for mechatronic components. The laser source is a quantum cascade laser emitting at 10.56 μm, resonant with a strong absorption band of sulfur hexafluoride (SF6), which was selected as target gas for leak detection. The minimum detectable concentration of the QEPAS sensor is 6.9 ppb with an integration time of 1 s. This detection sensitivity allowed to measure SF6 leak flows as low as 3x10-5 standard cm3.

  16. Compact Instruments Measure Helium-Leak Rates

    NASA Technical Reports Server (NTRS)

    Stout, Stephen; Immer, Christopher

    2003-01-01

    Compact, lightweight instruments have been developed for measuring small flows of helium and/or detecting helium leaks in solenoid valves when the valves are nominally closed. These instruments do not impede the flows when the valves are nominally open. They can be integrated into newly fabricated valves or retrofitted to previously fabricated valves. Each instrument includes an upstream and a downstream thermistor separated by a heater, plus associated analog and digital heater-control, signal- conditioning, and data-processing circuits. The thermistors and heater are off-the-shelf surface mount components mounted on a circuit board in the flow path. The operation of the instrument is based on a well-established thermal mass-flow-measurement technique: Convection by the flow that one seeks to measure gives rise to transfer of heat from the heater to the downstream thermistor. The temperature difference measured by the thermistors is directly related to the rate of flow. The calibration curve from temperature gradient to helium flow is closely approximated via fifth-order polynomial. A microprocessor that is part of the electronic circuitry implements the calibration curve to compute the flow rate from the thermistor readings.

  17. Leak detection system upgrades Cochin pipeline

    SciTech Connect

    Wray, B.; O`Leary, C.

    1996-02-01

    Amoco Canada`s Cochin pipeline system consists of 1,900 miles of 12-inch pipeline, 31 pump stations, eight injection/delivery stations and five propane terminals. It originates just northeast of Edmonton and crosses into the US in North Dakota, runs south of Lake Michigan, turns northeast to pass through Detroit and terminates in Sarnia, Ontario. In 1991, it was decided to significantly upgrade facilities for operating the Cochin pipeline. The control center hardware was obsolete, including parts and components no longer available. Also, SCADA and modeling software was no longer supported by outside vendors or consultants and there was only limited in-house support available. The land-based communications system was unreliable and expensive. Goals for the upgrade project included maintaining (improving) reliability and minimizing operating risks. Amoco Canada wanted to ensure reliable operations and support, provide reliable and effective leak detection, establish dependable communications, have the capability to respond to market additions or changes and maintain customer and regulatory confidence. Another important goal was to minimize operating costs. Specifically, methods were sought to minimize power costs, communications expense and support and maintenance expenditures while eliminating non-productive work. This paper reviews the resulting design and performance of this system.

  18. Effects of a documented hydrogen fluoride leak

    SciTech Connect

    Feder, W.A.

    1985-01-01

    At about 6 a.m. on June 19, 1984, 1037 liters of pressurized HF liquid escaped from a storage tank through a 2 mm diameter hole. 48 hours after the leak was discovered and sealed, visible injury to vegetation was observed 2 miles downwind of the source in a tear drop pattern. Injury symptoms ranged from a slight browning of leaves and needles to death of twigs and leaves and needles. Poplar, white pine, spruce, oak, red maple and several herbaceous plant species were injured. Ragweed was not injured but sensitive fern was severely injured. Goldenrod was also injured but recovered within 3 weeks after exposure. White pine trees within 1/4 of a mile from the source were killed. Fluoride analysis of tissues from upwind and downwind trees and herbaceous plants revealed fluoride tissue levels ranging from 5 to 34,000 ppm. Examples of distance/concentration are given. Soils revealed fluoride levels of about 1 ppm at all locations.

  19. Low heat leak connector for cryogenic system

    NASA Technical Reports Server (NTRS)

    Stelts, P. D. (Inventor)

    1965-01-01

    Heat leak from the surrounding atmosphere during fluid transfer from a spaced shell-insulated vessel for storing liquified gas having an upper gaseous phase, in minimized by forming a relatively wide, shallow blister on the wall of the vessel at the point of transfer line connection. The shell and the opposed walls of the blister have aligned openings whose common axis passes centrally through the blister and is normal to the surfaces of the vessel and shell. A fluid transfer line conduit passing through the shell opening is in fluid-tight connection with the shell and blister wall. The fluid transfer line confines the fluid in a continuous stream. The blister is filled with a heat insulating material which provides a thermal break between the central wall portions of the blister. A connector at the bottom of the vessel comprises a tube extending between the openings in the blister which projects a short distance within the body of liquefied gas and terminates in a reverse bend to prevent backflow of liquid through the pipe.

  20. Sodium leak channel, non-selective contributes to the leak current in human myometrial smooth muscle cells from pregnant women

    PubMed Central

    Reinl, Erin L.; Cabeza, Rafael; Gregory, Ismail A.; Cahill, Alison G.; England, Sarah K.

    2015-01-01

    Uterine contractions are tightly regulated by the electrical activity of myometrial smooth muscle cells (MSMCs). These cells require a depolarizing current to initiate Ca2+ influx and induce contraction. Cationic leak channels, which permit a steady flow of cations into a cell, are known to cause membrane depolarization in many tissue types. Previously, a Gd3+-sensitive, Na+-dependent leak current was identified in the rat myometrium, but the presence of such a current in human MSMCs and the specific ion channel conducting this current was unknown. Here, we report the presence of a Na+-dependent leak current in human myometrium and demonstrate that the Na+-leak channel, NALCN, contributes to this current. We performed whole-cell voltage-clamp on fresh and cultured MSMCs from uterine biopsies of term, non-laboring women and isolated the leak currents by using Ca2+ and K+ channel blockers in the bath solution. Ohmic leak currents were identified in freshly isolated and cultured MSMCs with normalized conductances of 14.6 pS/pF and 10.0 pS/pF, respectively. The myometrial leak current was significantly reduced (P < 0.01) by treating cells with 10 μM Gd3+ or by superfusing the cells with a Na+-free extracellular solution. Reverse transcriptase PCR and immunoblot analysis of uterine biopsies from term, non-laboring women revealed NALCN messenger RNA and protein expression in the myometrium. Notably, ∼90% knockdown of NALCN protein expression with lentivirus-delivered shRNA reduced the Gd3+-sensitive leak current density by 42% (P < 0.05). Our results reveal that NALCN, in part, generates the leak current in MSMCs and provide the basis for future research assessing NALCN as a potential molecular target for modulating uterine excitability. PMID:26134120

  1. Sodium leak channel, non-selective contributes to the leak current in human myometrial smooth muscle cells from pregnant women.

    PubMed

    Reinl, Erin L; Cabeza, Rafael; Gregory, Ismail A; Cahill, Alison G; England, Sarah K

    2015-10-01

    Uterine contractions are tightly regulated by the electrical activity of myometrial smooth muscle cells (MSMCs). These cells require a depolarizing current to initiate Ca(2+) influx and induce contraction. Cationic leak channels, which permit a steady flow of cations into a cell, are known to cause membrane depolarization in many tissue types. Previously, a Gd(3+)-sensitive, Na(+)-dependent leak current was identified in the rat myometrium, but the presence of such a current in human MSMCs and the specific ion channel conducting this current was unknown. Here, we report the presence of a Na(+)-dependent leak current in human myometrium and demonstrate that the Na(+)-leak channel, NALCN, contributes to this current. We performed whole-cell voltage-clamp on fresh and cultured MSMCs from uterine biopsies of term, non-laboring women and isolated the leak currents by using Ca(2+) and K(+) channel blockers in the bath solution. Ohmic leak currents were identified in freshly isolated and cultured MSMCs with normalized conductances of 14.6 pS/pF and 10.0 pS/pF, respectively. The myometrial leak current was significantly reduced (P < 0.01) by treating cells with 10 μM Gd(3+) or by superfusing the cells with a Na(+)-free extracellular solution. Reverse transcriptase PCR and immunoblot analysis of uterine biopsies from term, non-laboring women revealed NALCN messenger RNA and protein expression in the myometrium. Notably, ∼90% knockdown of NALCN protein expression with lentivirus-delivered shRNA reduced the Gd(3+)-sensitive leak current density by 42% (P < 0.05). Our results reveal that NALCN, in part, generates the leak current in MSMCs and provide the basis for future research assessing NALCN as a potential molecular target for modulating uterine excitability.

  2. Non-zero basal oxygen flow a hazard to anesthesia breathing circuit leak test.

    PubMed

    Tokumine, Joho; Sugahara, Kazuhiro; Gushiken, Kouji; Ohta, Minoru; Matsuyama, Tomoaki; Saikawa, Satoko

    2005-04-01

    The non-zero basal flow (BF) of oxygen in anesthesia machines has been set to supply the basal metabolic requirement of oxygen. However, there is no scientific evidence of its necessity. In this study we sought to clarify whether non-zero BF affects leak detection during preanesthetic inspections. Twenty-five participants performed leak tests on anesthesia machines to detect breathing circuit leaks. Artificial leak-producing devices were used to create leaks from 0 to 1.0 L/min. The investigator randomly chose the leak device and connected it into the breathing circuit. Participants, blinded as to the presence or the type of leak producing device, then tested the breathing circuit for leaks. The conventional breathing system leak test was performed with and without BF. The results of leak detection in each leak procedure were analyzed statistically. The leak detection rate of leak test with BF was less than without BF (P < 0.01). We demonstrated that non-zero BF of oxygen decreases the leak detection rate and is an obstacle for leak detection, especially for small leaks. Therefore, we recommend that breathing circuit leak tests should be performed in the absence of BF of oxygen.

  3. 40 CFR 63.648 - Equipment leak standards.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (except for the agitator provisions). The leak definition for valves, connectors, and instrumentation... service and agitators in heavy liquid service, owners and operators are not required to comply with...

  4. 40 CFR 63.648 - Equipment leak standards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (except for the agitator provisions). The leak definition for valves, connectors, and instrumentation... service and agitators in heavy liquid service, owners and operators are not required to comply with...

  5. 40 CFR 63.648 - Equipment leak standards.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (except for the agitator provisions). The leak definition for valves, connectors, and instrumentation... service and agitators in heavy liquid service, owners and operators are not required to comply with...

  6. 40 CFR 63.648 - Equipment leak standards.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (except for the agitator provisions). The leak definition for valves, connectors, and instrumentation... service and agitators in heavy liquid service, owners and operators are not required to comply with...

  7. 40 CFR 63.648 - Equipment leak standards.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (except for the agitator provisions). The leak definition for valves, connectors, and instrumentation... service and agitators in heavy liquid service, owners and operators are not required to comply with...

  8. Numerical Simulation of Gas Leaking Diffusion from Storage Tank

    NASA Astrophysics Data System (ADS)

    Zhu, Hongjun; Jing, Jiaqiang

    Over 80 percents of storage tank accidents are caused by gas leaking. Since traditional empirical calculation has great errors, present work aims to study the gas leaking diffusion under different wind conditions by numerical simulation method based on computational fluid dynamics theory. Then gas concentration distribution was obtained to determine the scope of the security zone. The results showed that gas diffused freely along the axis of leaking point without wind, giving rise to large range of hazardous area. However, wind plays the role of migrating and diluting the leaking gas. The larger is the wind speed, the smaller is the damage and the bigger is the security zone. Calculation method and results can provide some reference to establish and implement rescue program for accidents.

  9. 40 CFR 61.135 - Standard: Equipment leaks.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Emissions from Coke By-Product Recovery Plants § 61.135 Standard: Equipment leaks. (a) Each owner or... system that purges the barrier fluid into a process stream with zero benzene emissions to the...

  10. 40 CFR 61.135 - Standard: Equipment leaks.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Emissions from Coke By-Product Recovery Plants § 61.135 Standard: Equipment leaks. (a) Each owner or... system that purges the barrier fluid into a process stream with zero benzene emissions to the...

  11. 40 CFR 61.135 - Standard: Equipment leaks.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Emissions from Coke By-Product Recovery Plants § 61.135 Standard: Equipment leaks. (a) Each owner or... system that purges the barrier fluid into a process stream with zero benzene emissions to the...

  12. 40 CFR 61.135 - Standard: Equipment leaks.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Emissions from Coke By-Product Recovery Plants § 61.135 Standard: Equipment leaks. (a) Each owner or... system that purges the barrier fluid into a process stream with zero benzene emissions to the...

  13. 40 CFR 61.135 - Standard: Equipment leaks.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Emissions from Coke By-Product Recovery Plants § 61.135 Standard: Equipment leaks. (a) Each owner or... system that purges the barrier fluid into a process stream with zero benzene emissions to the...

  14. Clinical challenges of persistent pulmonary air-leaks--case report.

    PubMed

    van Zeller, M; Bastos, P; Fernandes, G; Magalhães, A

    2014-01-01

    Air leaks are a common problem after pulmonary resection and can be a source of significant morbidity and mortality. The authors describe the case of a 68-year-old male patient who presented with a persistent air-leak after pulmonary resection. Watchful waiting, surgical procedures, as well as medical therapy like pleurodesis and implantation of endobronchial one-way valves on the bronchial segments identified using systematic occlusion of the bronchial segments, were all tried unsuccessfully. During that time the patient remained hospitalized with a chest tube. The instillation of methylene blue through the chest tube was used to identify the segments leading to the persistent air-leak; this enabled successful endobronchial valve placement which sufficiently reduced the size of the air-leak so that the chest tube could be removed. Nonsurgical approaches seem promising and, for some patients may be the only treatment option after all conventional treatments have failed or are considered too high risk.

  15. An ultrasonic array sensor for spacecraft leak direction finding.

    PubMed

    Holland, Stephen D; Roberts, Ron; Chimenti, D E; Song, Jun Ho

    2006-12-01

    We have developed an ultrasonic array sensor useable for locating air leaks in manned spacecraft and have found that this sensor locates leaks in a 1-m(2) plate to within 2 cm. The sensor consists of a 63-element multiplexed array plus a reference element, all constructed from a single PZT disc and a printed circuit board. Cross-correlations of signals from the array elements with signals from the single reference element provide a measurement of the leak noise passing through the spacecraft skin under the array. A spatial Fourier transform reveals the dominant direction of propagation. Triangulation from multiple sensor locations can be used to find the source of the leak.

  16. Thermographic Leak Detection of the Space Shuttle Main Engine Nozzle

    NASA Technical Reports Server (NTRS)

    Walker, James L.; Russell, Samuel S.

    1999-01-01

    The Space Shuttle Main Engines Nozzles consist of over one thousand tapered Inconel coolant tubes brazed to a stainless steel structural jacket. Liquid Hydrogen flows through the tubing, from the aft to forward end of the nozzle, under high pressure to maintain a thermal balance between the rocket exhaust and the nozzle wall. Three potential problems occur within the SSME nozzle coolant tubes as a result of manufacturing anomalies and the highly volatile service environment including poor or incomplete bonding of the tubes to the structural jacket, cold wall leaks and hot wall leaks. Of these conditions the identification of cold wall leaks has been the most problematic. The methods and results presented in this summary addresses the thermographic identification of cold wall "interstitial" leaks between the structural jacket and coolant tubes of the Space Shuttle Main Engines Nozzles.

  17. Standard Test Procedures for Evaluating Various Leak Detection Methods

    EPA Pesticide Factsheets

    Learn about protocols that testers could use to demonstrate that an individual release detection equipment type could meet the performance requirements noted in the federal UST requirements for detecting leaks.

  18. Minimally Invasive, Nonsurgical Approach to Repairing Mitral Valve Leaks

    MedlinePlus

    Minimally Invasive, Nonsurgical Approach to Repairing Mitral Valve Leaks - David X. Zhao, MD Click Here to view the BroadcastMed, Inc. Privacy Policy and Legal Notice © 2017 BroadcastMed, Inc. All rights ...

  19. Multivariate thermo-hygrometric characterisation of the archaeological site of Plaza de l'Almoina (Valencia, Spain) for preventive conservation.

    PubMed

    Fernández-Navajas, Angel; Merello, Paloma; Beltrán, Pedro; García-Diego, Fernando-Juan

    2013-07-29

    Preventive conservation requires monitoring and control of the parameters involved in the deterioration process, mainly temperature and relative humidity. It is important to characterise an archaeological site prior to carrying out comparative studies in the future for preventive conservation, either by regular studies to verify whether the conditions are constant, or occasional ones when the boundary conditions are altered. There are numerous covered archaeological sites, but few preventive conservation works that give special attention to the type of cover installed. In particular, there is no background of microclimatic studies in sites that are in the ground and, as in the Plaza de l'Almoina (Valencia, Spain), are buried and partially covered by a transparent roof. A large effect of the transparent cover was found by the sensors located below this area, with substantial increases in temperature and a decrease in the relative humidity during the day. Surrounding zones also have values above the recommended temperature values. On the other hand, the influence of a buried water drainage line near the site is notable, causing an increase in relative humidity levels in the surrounding areas. Multivariate statistical analyses enabled us to characterise the microclimate of the archaeological site, allowing future testing to determine whether the conservation conditions have been altered.

  20. Multivariate Thermo-Hygrometric Characterisation of the Archaeological Site of Plaza de l’Almoina (Valencia, Spain) for Preventive Conservation

    PubMed Central

    Fernández-Navajas, Ángel; Merello, Paloma; Beltrán, Pedro; García-Diego, Fernando-Juan

    2013-01-01

    Preventive conservation requires monitoring and control of the parameters involved in the deterioration process, mainly temperature and relative humidity. It is important to characterise an archaeological site prior to carrying out comparative studies in the future for preventive conservation, either by regular studies to verify whether the conditions are constant, or occasional ones when the boundary conditions are altered. There are numerous covered archaeological sites, but few preventive conservation works that give special attention to the type of cover installed. In particular, there is no background of microclimatic studies in sites that are in the ground and, as in the Plaza de l’Almoina (Valencia, Spain), are buried and partially covered by a transparent roof. A large effect of the transparent cover was found by the sensors located below this area, with substantial increases in temperature and a decrease in the relative humidity during the day. Surrounding zones also have values above the recommended temperature values. On the other hand, the influence of a buried water drainage line near the site is notable, causing an increase in relative humidity levels in the surrounding areas. Multivariate statistical analyses enabled us to characterise the microclimate of the archaeological site, allowing future testing to determine whether the conservation conditions have been altered. PMID:23899937

  1. Space Shuttle RCS Oxidizer Leak Repair for STS-26

    NASA Technical Reports Server (NTRS)

    Delventhal, R. A.; Faget, N. M.

    1989-01-01

    Following propellant loading of the Space Shuttle's reaction control system (RCS) for mission STS 26, an oxidizer leak was detected in the left orbital maneuvering system (OMS) pod, where the RCS is located. Subsequent investigation determined that the leak was isolated at a mechanical Dynatube fitting near the RCS nitrogen tetroxide tank. An intense effort was initiated to design, fabricate, and qualify a sealing device to stop the oxidizer leak externally so that the Space Shuttle launch could proceed. It was discovered that sealing devices called clamshells were widely used throughout the petrochemical and power generation industries to stop leaks developed in large diameter pipes which carry steam or other hazardous fluids. These clamshells are available in different diameters and strengths and are placed around the pipe at the location of the leak. A sealing compound is then injected under high pressure into the clamshell to stop the leak. This technology was scaled down and applied to the problem of stopping the leak on the Orbiter, which was on a half-inch diameter line in a nearly inaccessible location. Many obstacles had to be overcome such as determining that the sealing material would be compatible with the nitrogen tetroxide and ensuring that the clamshell would actually fit around the Dynatube fitting without interfering with other lines which were in close proximity. The effort at the NASA Johnson Space Center included materials compatibility testing of several sealants, design of a clamshell to fit in the confined compartment, and manufacture and qualification of the flight hardware. A clamshell was successfully placed around the Dynatube fitting on the Orbiter and the oxidizer leak was terminated. Then it was decided to apply this technology further and design clamshells for other mechanical fittings onboard the Orbiter and develop sealing compounds which will be compatible with fuels such as monomethyl hydrazine (MMH). The potential exists for

  2. Identification of sewage leaks by active remote-sensing methods

    NASA Astrophysics Data System (ADS)

    Goldshleger, Naftaly; Basson, Uri

    2016-04-01

    The increasing length of sewage pipelines, and concomitant risk of leaks due to urban and industrial growth and development is exposing the surrounding land to contamination risk and environmental harm. It is therefore important to locate such leaks in a timely manner, to minimize the damage. Advances in active remote sensing Ground Penetrating Radar (GPR) and Frequency Domain Electromagnetic (FDEM) technologies was used to identify leaking potentially responsible for pollution and to identify minor spills before they cause widespread damage. This study focused on the development of these electromagnetic methods to replace conventional acoustic methods for the identification of leaks along sewage pipes. Electromagnetic methods provide an additional advantage in that they allow mapping of the fluid-transport system in the subsurface. Leak-detection systems using GPR and FDEM are not limited to large amounts of water, but enable detecting leaks of tens of liters per hour, because they can locate increases in environmental moisture content of only a few percentage along the pipes. The importance and uniqueness of this research lies in the development of practical tools to provide a snapshot and monitoring of the spatial changes in soil moisture content up to depths of about 3-4 m, in open and paved areas, at relatively low cost, in real time or close to real time. Spatial measurements performed using GPR and FDEM systems allow monitoring many tens of thousands of measurement points per hectare, thus providing a picture of the spatial situation along pipelines and the surrounding. The main purpose of this study was to develop a method for detecting sewage leaks using the above-proposed geophysical methods, since their contaminants can severely affect public health. We focused on identifying, locating and characterizing such leaks in sewage pipes in residential and industrial areas.

  3. Ultrafine cement seals slow leak in casing collar

    SciTech Connect

    Mac Eachern, D. ); Young, S.C. )

    1992-09-07

    This paper reports that an ultrafine cement squeeze effectively sealed a difficult casing collar leak in the protective casing in a deep, high-temperature well in Mobile Bay. The leak was sealed in one operation without perforating the casing, giving greater confidence in casing integrity and allowing the well to be drilled to total depth (TD). Restoring pressure integrity of the casing with this procedure saved approximately $250,000.

  4. Maintenance, Leak Detection in Large Underground Storage Tanks

    DTIC Science & Technology

    2009-05-01

    Responsive! FISC Puget Sound Manchester Fuel Department Maintenance, Leak Detection in Large Underground Storage Tanks Report Documentation Page Form...COVERED 00-00-2009 to 00-00-2009 4. TITLE AND SUBTITLE Maintenance, Leak Detection in Large Underground Storage Tanks 5a. CONTRACT NUMBER 5b...Manchester 13 Regulatory Drivers 40 CFR 280/281 Derives Basic Regulation of Underground Storage Tanks These tanks are Field Constructed – therefore

  5. SSME propellant path leak detection real-time

    NASA Technical Reports Server (NTRS)

    Crawford, R. A.; Smith, L. M.

    1994-01-01

    Included are four documents that outline the technical aspects of the research performed on NASA Grant NAG8-140: 'A System for Sequential Step Detection with Application to Video Image Processing'; 'Leak Detection from the SSME Using Sequential Image Processing'; 'Digital Image Processor Specifications for Real-Time SSME Leak Detection'; and 'A Color Change Detection System for Video Signals with Applications to Spectral Analysis of Rocket Engine Plumes'.

  6. Tank 241-A-105 leak assessment

    SciTech Connect

    Not Available

    1991-06-01

    Tank 241-A-105 is one of 149 single shell tanks constructed at Hanford to contain and store highly radioactive wastes originating from the processing of spent nuclear reactor fuel. Radiation detection and temperature monitoring devices installed beneath the tank indicate that several episodes of leakage of waste from the tank have occurred. The aim of this study was to evaluate the previous estimates and reanalyze the data to provide a more accurate estimate of leakage from the tank. The principal conclusions of this study are as follows: Earlier investigators estimated leakage prior to August 1968 at 5,000 to 15,000 gallons. Their estimate appears reasonable. Leakage while the tank was being sluiced (8/68--11/70) probably exceeded 5,000 gallons, but probably did not exceed 30,000 gallons. Insufficient data are available to be more precise. Cooling water added to the tank during the sprinkling phase (11/70 -- 12/78) was approximately 610,000 gallons. Sufficient heat was generated in the tank to evaporate most, and perhaps nearly all, of this water. Radionuclides escaping into the soil under the tank cannot be estimated directly because of many uncertainties. Based on a range of leakage from 10,000 to 45,000 gallons, assumed compositions, and decayed to 1/1/91, radioactivity under the tank is expected to be in the range of 85,000--760,000 curies. Measured radiation peaks were nearly all located directly below the perimeter of the tank and, except in rare cases, they showed no tendency to spread horizontally. Moreover, the maximum radiation readings detected are a very small fraction of the radiation reading in the tank. This is the basis for the conclusion that the rate of leakage and, most likely, the quantity leaked, was small. 51 refs., 5 figs., 3 tabs.

  7. Local Leak Detection and Health Monitoring of Pressurized Tanks

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt; Witherow, William; Korman, Valentin; Sinko, John; Hendrickson, Adam

    2011-01-01

    An optical gas-detection sensor safely monitors pressurized systems (such as cryogenic tanks) and distribution systems for leaks. This sensor system is a fiber-coupled, solid optical body interferometer that allows for the miniaturized sensing element of the device to be placed in the smallest of recesses, and measures a wide range of gas species and densities (leaks). The deflection of the fringe pattern is detected and recorded to yield the time-varying gas density in the gap. This technology can be used by manufacturers or storage facilities with toxic, hazardous, or explosive gases. The approach is to monitor the change in the index of refraction associated with low-level gas leaks into a vacuum environment. The completion of this work will provide NASA with an enabling capability to detect gas system leaks in space, and to verify that pressurized systems are in a safe (i.e. non-leaking) condition during manned docking and transit operations. By recording the output of the sensor, a time-history of the leak can be constructed to indicate its severity. Project risk is mitigated by having several interferometric geometries and detection techniques available, each potentially leveraging hardware and lessons learned to enhance detectability.

  8. Methane Leaks from Natural Gas Systems Follow Extreme Distributions

    SciTech Connect

    Brandt, Adam R.; Heath, Garvin A.; Cooley, Daniel

    2016-10-14

    Future energy systems may rely on natural gas as a low-cost fuel to support variable renewable power. However, leaking natural gas causes climate damage because methane (CH4) has a high global warming potential. In this study, we use extreme-value theory to explore the distribution of natural gas leak sizes. By analyzing ~15,000 measurements from 18 prior studies, we show that all available natural gas leakage datasets are statistically heavy-tailed, and that gas leaks are more extremely distributed than other natural and social phenomena. A unifying result is that the largest 5% of leaks typically contribute over 50% of the total leakage volume. While prior studies used lognormal model distributions, we show that lognormal functions poorly represent tail behavior. Our results suggest that published uncertainty ranges of CH4 emissions are too narrow, and that larger sample sizes are required in future studies to achieve targeted confidence intervals. Additionally, we find that cross-study aggregation of datasets to increase sample size is not recommended due to apparent deviation between sampled populations. Finally, understanding the nature of leak distributions can improve emission estimates, better illustrate their uncertainty, allow prioritization of source categories, and improve sampling design. Also, these data can be used for more effective design of leak detection technologies.

  9. Reduction of persistent air leak with endoscopic valve implants.

    PubMed

    Toma, Tudor P; Kon, Onn Min; Oldfield, William; Sanefuji, Reina; Griffiths, Mark; Wells, Frank; Sivasothy, Siva; Dusmet, Michael; Geddes, Duncan M; Polkey, Michael I

    2007-09-01

    The standard management of air leaks due to persistent bronchopleural fistula involves chest drainage and occasionally pleurodesis, with intractable cases requiring surgical decortication or surgical repair. However, some of these patients may be at high risk for surgery, particularly if they have already had thoracic surgery or have other medical problems; for this group there is a need for less invasive methods of stopping or reducing air leaks. Emphasys endobronchial valves (EBV) are occlusive devices designed primarily for endoscopic lung volume reduction in emphysema. Because the device is a one-way inspiratory airway blocker, it is possible that it could be used in controlling persistent air leaks while maintaining the drainage of secretions. Two cases are reported of persistent air leaks that were managed by endoscopic occlusion with EBV. In one case complete stoppage of the air leak was achieved with immediate clinical benefits. The second patient died 5 days after treatment from additional complications apparently not related to the procedure. Endobronchial blockage may be a useful salvage procedure for patients with persistent air leak for whom there is no other treatment available.

  10. Measurement of Submerged Oil/Gas Leaks using ROV Video

    NASA Astrophysics Data System (ADS)

    Shaffer, Franklin; de Vera, Giorgio; Lee, Kenneth; Savas, Ömer

    2013-11-01

    Drilling for oil or gas in the Gulf of Mexico is increasing rapidly at depths up to three miles. The National Commission on the Deepwater Horizon Oil Leak concluded that inaccurate estimates of the leak rate from the Deepwater Horizon caused an inadequate response and attempts to cap the leak to fail. The first response to a submerged oil/gas leak will be to send a Remotely Operated Vehicle (ROV) down to view the leak. During the response to the Deepwater Horizon crisis, the authors Savas and Shaffer were members of the Flow Rate Technical Group's Plume Team who used ROV video to develop the FRTG's first official estimates of the oil leak rate. Savas and Shaffer developed an approach using the larger, faster jet features (e.g., turbulent eddies, vortices, entrained particles) in the near-field developing zone to measure discharge rates. The authors have since used the Berkeley Tow Tank to test this approach on submerged dye-colored water jets and compressed air jets. Image Correlation Velocimetry has been applied to measure the velocity of visible features. Results from tests in the Berkeley Tow Tank and submerged oil jets in the OHMSETT facility will be presented.

  11. Leak test fixture and method for using same

    DOEpatents

    Hawk, Lawrence S.

    1976-01-01

    A method and apparatus are provided which are especially useful for leak testing seams such as an end closure or joint in an article. The test does not require an enclosed pressurized volume within the article or joint section to be leak checked. A flexible impervious membrane is disposed over an area of the seamed surfaces to be leak checked and sealed around the outer edges. A preselected vacuum is applied through an opening in the membrane to evacuate the area between the membrane and the surface being leak checked to essentially collapse the membrane to conform to the article surface or joined adjacent surfaces. A pressure differential is concentrated at the seam bounded by the membrane and only the seam experiences a pressure differential as air or helium molecules are drawn into the vacuum system through a leak in the seam. A helium detector may be placed in a vacuum exhaust line from the membrane to detect the helium. Alternatively, the vacuum system may be isolated at a preselected pressure and leaks may be detected by a subsequent pressure increase in the vacuum system.

  12. Passive vapor monitoring of underground storage tanks for leak detection.

    PubMed

    Weber, D; Schwille, F

    1991-02-01

    Passive vapor monitoring of underground storage tanks (USTs) containing volatile hydrocarbons at locations external to the tank (an external system) is touted as a fast and effective method of leak detection. However, major gaps remain in our knowledge of the physical processes that relate a measured vapor concentration to the leak rate, thus making network design according to a quantitative design criterion nearly impossible, and differentiation between surface spills and a leaking UST requires certain levels of sophistication in the leak detection system and in the analysis that are not usually available. Heavier-than-air vapors from the constituents of stored hydrocarbons could result in a density-driven convective propagation component that complicates the design of leak detection systems, and finally, detection times are highly sensitive to concentration detection threshold levels set by the system. The use of inadequate systems and analyses can lead to either wasted efforts or excessive subsurface contamination. This paper discusses the physical processes involved, explores the above aspects of external passive vapor leak detection design, and suggests some alternatives as they pertain to gasoline service stations.

  13. Methane Leaks from Natural Gas Systems Follow Extreme Distributions

    DOE PAGES

    Brandt, Adam R.; Heath, Garvin A.; Cooley, Daniel

    2016-10-14

    Future energy systems may rely on natural gas as a low-cost fuel to support variable renewable power. However, leaking natural gas causes climate damage because methane (CH4) has a high global warming potential. In this study, we use extreme-value theory to explore the distribution of natural gas leak sizes. By analyzing ~15,000 measurements from 18 prior studies, we show that all available natural gas leakage datasets are statistically heavy-tailed, and that gas leaks are more extremely distributed than other natural and social phenomena. A unifying result is that the largest 5% of leaks typically contribute over 50% of the totalmore » leakage volume. While prior studies used lognormal model distributions, we show that lognormal functions poorly represent tail behavior. Our results suggest that published uncertainty ranges of CH4 emissions are too narrow, and that larger sample sizes are required in future studies to achieve targeted confidence intervals. Additionally, we find that cross-study aggregation of datasets to increase sample size is not recommended due to apparent deviation between sampled populations. Finally, understanding the nature of leak distributions can improve emission estimates, better illustrate their uncertainty, allow prioritization of source categories, and improve sampling design. Also, these data can be used for more effective design of leak detection technologies.« less

  14. Hazardous Gas Leak Analysis in the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Barile, Ronald G.

    1991-01-01

    Helium tests of the main propulsion system in the Space Shuttle and on hydrogen leaks are examined. The hazardous gas detection system (HGDS) in the mobile launch pad uses mass spectrometers (MS) to monitor the shuttle environment for leaks. The mass spectrometers are fed by long tubes to sample gas from the payload bay, mid-body, aft engine compartment, and external tank. The purpose is to improve the HGDS, especially in its potential for locating cryogen leaks. Pre-existing leak data was analyzed for transient information to determine if the leak location could be pinpointed from test data. A rapid response leak detection experiment was designed, built, and tested. Large eddies and vortices were visually seen with Schlieren imaging, and they were detected in the time plots of the various instruments. The response time of the MS was found in the range of 0.05 to 0.1 sec. Pulsed concentration waves were clearly detected at 25 cycles per sec by spectral analysis of MS data. One conclusion is that the backup HGDS sampling frequency should be increased above the present rate of 1 sample per second.

  15. Methane Leaks from Natural Gas Systems Follow Extreme Distributions.

    PubMed

    Brandt, Adam R; Heath, Garvin A; Cooley, Daniel

    2016-11-15

    Future energy systems may rely on natural gas as a low-cost fuel to support variable renewable power. However, leaking natural gas causes climate damage because methane (CH4) has a high global warming potential. In this study, we use extreme-value theory to explore the distribution of natural gas leak sizes. By analyzing ∼15 000 measurements from 18 prior studies, we show that all available natural gas leakage data sets are statistically heavy-tailed, and that gas leaks are more extremely distributed than other natural and social phenomena. A unifying result is that the largest 5% of leaks typically contribute over 50% of the total leakage volume. While prior studies used log-normal model distributions, we show that log-normal functions poorly represent tail behavior. Our results suggest that published uncertainty ranges of CH4 emissions are too narrow, and that larger sample sizes are required in future studies to achieve targeted confidence intervals. Additionally, we find that cross-study aggregation of data sets to increase sample size is not recommended due to apparent deviation between sampled populations. Understanding the nature of leak distributions can improve emission estimates, better illustrate their uncertainty, allow prioritization of source categories, and improve sampling design. Also, these data can be used for more effective design of leak detection technologies.

  16. The ISS 2B PVTCS Ammonia Leak: An Operational History

    NASA Technical Reports Server (NTRS)

    Vareha, Anthony

    2014-01-01

    In 2006, the Photovoltaic Thermal Control System (PVTCS) for the International Space Station's 2B power channel began leaking ammonia at a rate of approximately 1.5lbm/year (out of a starting approximately 53lbm system ammonia mass). Initially, the operations strategy was "feed the leak," a strategy successfully put into action via Extra Vehicular Activity during the STS-134 mission. During this mission the system was topped off with ammonia piped over from a separate thermal control system. This recharge was to have allowed for continued power channel operation into 2014 or 2015, at which point another EVA would have been required. Without these periodic EVAs to refill the 2B coolant system, the channel would eventually leak enough fluid as to risk pump cavitation and system failure, resulting in the loss of the 2B power channel - the most critical of the Space Station's 8 power channels. In mid-2012, the leak rate increased to approximately 5lbm/year. Once discovered, an EVA was planned and executed within a 5 week timeframe to drastically alter the architecture of the PVTCS via connection to a dormant thermal control system not intended to be utilized as anything other than spare components. The purpose of this rerouting of the TCS was to increase system volume and to isolate the photovoltaic radiator, thought to be the likely leak source. This EVA was successfully executed on November 1st, 2012 and left the 2B PVTCS in a configuration where the system was now being adequately cooled via a totally different radiator than what the system was designed to utilize. Unfortunately, data monitoring over the next several months showed that the isolated radiator was not leaking, and the system itself continued to leak steadily until May 9th, 2013. It was on this day that the ISS crew noticed the visible presence of ammonia crystals escaping from the 2B channel's truss segment, signifying a rapid acceleration of the leak from 5lbm/year to 5lbm/day. Within 48 hours of the

  17. Fugitive methane emissions from leak-prone natural gas distribution infrastructure in urban environments.

    PubMed

    Hendrick, Margaret F; Ackley, Robert; Sanaie-Movahed, Bahare; Tang, Xiaojing; Phillips, Nathan G

    2016-06-01

    Fugitive emissions from natural gas systems are the largest anthropogenic source of the greenhouse gas methane (CH4) in the U.S. and contribute to the risk of explosions in urban environments. Here, we report on a survey of CH4 emissions from 100 natural gas leaks in cast iron distribution mains in Metro Boston, MA. Direct measures of CH4 flux from individual leaks ranged from 4.0 - 2.3 × 10(4) g CH4•day(-1). The distribution of leak size is positively skewed, with 7% of leaks contributing 50% of total CH4 emissions measured. We identify parallels in the skewed distribution of leak size found in downstream systems with midstream and upstream stages of the gas process chain. Fixing 'superemitter' leaks will disproportionately stem greenhouse gas emissions. Fifteen percent of leaks surveyed qualified as potentially explosive (Grade 1), and we found no difference in CH4 flux between Grade 1 leaks and all remaining leaks surveyed (p = 0.24). All leaks must be addressed, as even small leaks cannot be disregarded as 'safely leaking.' Key methodological impediments to quantifying and addressing the impacts of leaking natural gas distribution infrastructure involve inconsistencies in the manner in which gas leaks are defined, detected, and classified. To address this need, we propose a two-part leak classification system that reflects both the safety and climatic impacts of natural gas leaks.

  18. Prediction of Gas Leak Tightness of Superplastically Formed Products

    SciTech Connect

    Snippe, Corijn H. C.; Meinders, T.

    2010-06-15

    In some applications, in this case an aluminium box in a subatomic particle detector containing highly sensitive detecting devices, it is important that a formed sheet should show no gas leak from one side to the other. In order to prevent a trial-and-error procedure to make this leak tight box, a method is set up to predict if a formed sheet conforms to the maximum leak constraint. The technique of superplastic forming (SPF) is used in order to attain very high plastic strains before failure. Since only a few of these boxes are needed, this makes, this generally slow, process an attractive production method. To predict the gas leak of a superplastically formed aluminium sheet in an accurate way, finite element simulations are used in combination with a user-defined material model. This constitutive model couples the leak rate with the void volume fraction. This void volume fraction is then dependent on both the equivalent plastic strain and the applied hydrostatic pressure during the bulge process (backpressure).

  19. Leak detection by acoustic emission monitoring. Phase 1: Feasibility study

    NASA Astrophysics Data System (ADS)

    Lichtenstein, Bernard; Winder, A. A.

    1994-05-01

    This investigation was conducted to determine the feasibility of detecting leaks from underground storage tanks or pipelines using acoustic emissions. An extensive technical literature review established that distinguishable acoustic emission signals will be generated when a storage tank is subjected to deformation stresses. A parametric analysis was performed which indicated that leak rates less than 0.1 gallons per hour can be detected for leak sizes less than 1/32 inch with 99% probability if the transient signals were sensed with an array of accelerometers (cemented to the tank or via acoustic waveguides), each having a sensitivity greater than 250 mv/g over a frequency range of 0.1 to 4000 Hz, and processed in a multi-channel Fourier spectrum analyzer with automatic threshold detection. An acoustic transient or energy release processor could conceivably detect the onset of the leak at the moment of fracture of the tank wall. The primary limitations to realizing reliable and robust acoustic emission monitoring of underground fluid leaks are the various masking noise sources prevalent at Air Force bases, which are attributed to aircraft, motor traffic, pump station operation, and ground tremors.

  20. Detecting leaks in hydrocarbon storage tanks using electrical resistance tomography

    SciTech Connect

    Daily, W.; Ramirez, A.; LaBrecque, D.; Binley, A.

    1995-04-03

    Large volumes of hydrocarbons are stored worldwide in surface and underground tanks. It is well documented [1] that all too often these tanks are found to leak, resulting in not only a loss of stored inventory but, more importantly, contamination to soil and groundwater. Two field experiments are reported herein to evaluate the utility of electrical resistance tomography (ERT) for detecting and locating leaks as well as delineating any resulting plumes emanating from steel underground storage tanks (UST). Current leak detection methods for single shell tanks require careful inventory monitoring, usually from liquid level sensors within the tank, or placement of chemical sensors in the soil under and around the tank. Liquid level sensors can signal a leak but are limited in sensitivity and, of course, give no information about the location or the leak or the distribution of the resulting plume. External sensors are expensive to retrofit and must be very densely spaced to assure reliable detection, especially in heterogeneous soils. The rational for using subsurface tomography is that it may have none of these shortcomings.

  1. CO2-Leaking Well - Analytical Modeling

    NASA Astrophysics Data System (ADS)

    Wertz, F.; Audigane, P.; Bouc, O.

    2009-04-01

    The long-term integrity of CO2 storage in geological system relies highly on local trapping mechanisms but also on the absence/control of any kind of outlets. Indeed numerous pathways (faults, wells, rock heterogeneities…) exist that can lead stored gas back to the surface. Thus, such leakage risks must be assessed and quantified if possible. In France, BRGM is inquired for evaluating safety criteria and developing a methodology for qualifying potential geological storage sites. This implies in particular to study the leakage scenario, here through a water-filled well as a worth scenario case. In order to determine the kinds of impacts leaking CO2 can have; knowing the velocity and flow rate of uprising CO2 is a necessity. That is why a better knowledge of CO2 in storage conditions and its behaviour with the environment is required. The following study aims at characterising the CO2 flowing into the well and then rising up in a water column over the vertical dimension. An analytical model was built that describes: - In a first step, the CO2 flow between the reservoir and the inside of the well, depending on quality and thickness of different seals, which determines the flow rate through the well. - In a second step, the CO2 uprising through an open and water filled well, however in steady state, which excludes a priori the characterisation of periodic or chaotic behaviours such as geyser formation. The objective is to give numerous orders of magnitude concerning CO2 thermodynamic properties while rising up: specific enthalpy, density, viscosity, velocity, flow, gas volume fraction and expansion, pressure and temperature gradient. Dissolution is partially taken into account, however without kinetic. The strength of this model is to compute analytically - easily and instantaneously - the 1-dimensional rising velocity of CO2 in a water column as a function of the CO2 density, interfacial tension and initial volume fraction. Characteristic speeds - the ones given by

  2. Hermetic Seal Leak Detection Apparatus with Variable Size Test Chamber

    NASA Technical Reports Server (NTRS)

    Kelley, Anthony R. (Inventor)

    2015-01-01

    The present invention is a versatile hermetic seal leak detection apparatus for testing hermetically sealed containers and devices for leaks without the need to create a custom or specially manufactured testing chamber conforming to the dimensions of the specific object under test. The size of the testing chamber may be mechanically adjusted by the novel use of bellows to reduce and optimize the amount of gas space in a test chamber which surrounds the hermetically sealed object under test. The present invention allows the size of the test chamber to be selectively adjusted during testing to provide an optimum test chamber gas space. The present invention may be further adapted to isolate and test specific portions of the hermetically sealed object under test for leaks.

  3. Gas-leak localization using distributed ultrasonic sensors

    NASA Astrophysics Data System (ADS)

    Huseynov, Javid; Baliga, Shankar; Dillencourt, Michael; Bic, Lubomir; Bagherzadeh, Nader

    2009-03-01

    We propose an ultrasonic gas leak localization system based on a distributed network of sensors. The system deploys highly sensitive miniature Micro-Electro-Mechanical Systems (MEMS) microphones and uses a suite of energy-decay (ED) and time-delay of arrival (TDOA) algorithms for localizing a source of a gas leak. Statistical tools such as the maximum likelihood (ML) and the least squares (LS) estimators are used for approximating the source location when closed-form solutions fail in the presence of ambient background nuisance and inherent electronic noise. The proposed localization algorithms were implemented and tested using a Java-based simulation platform connected to four or more distributed MEMS microphones observing a broadband nitrogen leak from an orifice. The performance of centralized and decentralized algorithms under ED and TDOA schemes is analyzed and compared in terms of communication overhead and accuracy in presence of additive white Gaussian noise (AWGN).

  4. Apparatus and method for detecting leaks in piping

    DOEpatents

    Trapp, D.J.

    1994-12-27

    A method and device are disclosed for detecting the location of leaks along a wall or piping system, preferably in double-walled piping. The apparatus comprises a sniffer probe, a rigid cord such as a length of tube attached to the probe on one end and extending out of the piping with the other end, a source of pressurized air and a source of helium. The method comprises guiding the sniffer probe into the inner pipe to its distal end, purging the inner pipe with pressurized air, filling the annulus defined between the inner and outer pipe with helium, and then detecting the presence of helium within the inner pipe with the probe as is pulled back through the inner pipe. The length of the tube at the point where a leak is detected determines the location of the leak in the pipe. 2 figures.

  5. Apparatus and method for detecting leaks in piping

    DOEpatents

    Trapp, Donald J.

    1994-01-01

    A method and device for detecting the location of leaks along a wall or piping system, preferably in double-walled piping. The apparatus comprises a sniffer probe, a rigid cord such as a length of tube attached to the probe on one end and extending out of the piping with the other end, a source of pressurized air and a source of helium. The method comprises guiding the sniffer probe into the inner pipe to its distal end, purging the inner pipe with pressurized air, filling the annulus defined between the inner and outer pipe with helium, and then detecting the presence of helium within the inner pipe with the probe as is pulled back through the inner pipe. The length of the tube at the point where a leak is detected determines the location of the leak in the pipe.

  6. Oil/gas collector/separator for underwater oil leaks

    SciTech Connect

    Henning, C.D.

    1992-12-31

    This invention is comprised of an oil/gas collector/separator for recovery of oil leaking, for example, from an offshore or underwater oil well. The separator is floated over the point of the leak and tethered in place so as to receive oil/gas floating, or forced under pressure, toward the water surface from either a broken or leaking oil well casing, line, or sunken ship. The separator is provided with a downwardly extending skirt to contain the oil/gas which floats or is forced upward into a dome wherein the gas is separated from the oil/water, with the gas being flared (burned) at the top of the dome, and the oil is separated from water and pumped to a point of use. Since the density of oil is less than that of water it can be easily separated from any water entering the dome.

  7. Echocardiographic findings in patients with spontaneous CSF leak.

    PubMed

    Pimienta, Allen L; Rimoin, David L; Pariani, Mitchel; Schievink, Wouter I; Reinstein, Eyal

    2014-10-01

    The presence of cardiovascular abnormalities in patients with spontaneous cerebrospinal fluid (CSF) leaks are not well-documented in the literature, as cardiovascular evaluation is not generally pursued if a patient does not exhibit additional clinical features suggesting an inherited connective tissue disorder. We aimed to assess this association, enrolling a consecutive group of 50 patients referred for spinal CSF leak consultation. Through echocardiographic evaluation and detailed medical history, we estimate that up to 20% of patients presenting with a spontaneous CSF leak may have some type of cardiovascular abnormality. Further, the increase in prevalence of aortic dilatation in our cohort was statistically significant in comparison to the estimated population prevalence. This supports a clinical basis for echocardiographic screening of these individuals for cardiovascular manifestations that may have otherwise gone unnoticed or evolved into a more severe manifestation.

  8. Oil/gas collector/separator for underwater oil leaks

    DOEpatents

    Henning, Carl D.

    1993-01-01

    An oil/gas collector/separator for recovery of oil leaking, for example, from an offshore or underwater oil well. The separator is floated over the point of the leak and tethered in place so as to receive oil/gas floating, or forced under pressure, toward the water surface from either a broken or leaking oil well casing, line, or sunken ship. The separator is provided with a downwardly extending skirt to contain the oil/gas which floats or is forced upward into a dome wherein the gas is separated from the oil/water, with the gas being flared (burned) at the top of the dome, and the oil is separated from water and pumped to a point of use. Since the density of oil is less than that of water it can be easily separated from any water entering the dome.

  9. Evaluation of advanced and current leak detection system

    SciTech Connect

    Kupperman, D.S.

    1987-01-01

    US Nuclear Regulatory Commission Guide 1.45 recommends the use of at least three different detection methods in reactors to detect leakage. Monitoring of both sump-flow and airborne particulate radioactivity is mandatory. A third method can involve either monitoring of condensate flow rate from air coolers or monitoring of airborne gaseous radioactivity. Although the methods currently used for leak detection reflect the state of the art, other techniques may be developed and used. Since the recommendations of Regulatory Guide 1.45 are not mandatory, Licensee Event Report Compilations have been reviewed to help establish actual capabilities for leak detection. The review of reports which had previously covered the period June 1985 to August 1986, has been extended. The total number of events of significance is now 83. These reports have provided documented, sometimes detailed summaries of reactor leaks.

  10. High Altitude Aerial Natural Gas Leak Detection System

    SciTech Connect

    Richard T. Wainner; Mickey B. Frish; B. David Green; Matthew C. Laderer; Mark G. Allen; Joseph R. Morency

    2006-12-31

    The objective of this program was to develop and demonstrate a cost-effective and power-efficient advanced standoff sensing technology able to detect and quantify, from a high-altitude (> 10,000 ft) aircraft, natural gas leaking from a high-pressure pipeline. The advanced technology is based on an enhanced version of the Remote Methane Leak Detector (RMLD) platform developed previously by Physical Sciences Inc. (PSI). The RMLD combines a telecommunications-style diode laser, fiber-optic components, and low-cost DSP electronics with the well-understood principles of Wavelength Modulation Spectroscopy (WMS), to indicate the presence of natural gas located between the operator and a topographic target. The transceiver transmits a laser beam onto a topographic target and receives some of the laser light reflected by the target. The controller processes the received light signal to deduce the amount of methane in the laser's path. For use in the airborne platform, we modified three aspects of the RMLD, by: (1) inserting an Erbium-doped optical fiber laser amplifier to increase the transmitted laser power from 10 mW to 5W; (2) increasing the optical receiver diameter from 10 cm to 25 cm; and (3) altering the laser wavelength from 1653 nm to 1618 nm. The modified RMLD system provides a path-integrated methane concentration sensitivity {approx}5000 ppm-m, sufficient to detect the presence of a leak from a high capacity transmission line while discriminating against attenuation by ambient methane. In ground-based simulations of the aerial leak detection scenario, we demonstrated the ability to measure methane leaks within the laser beam path when it illuminates a topographic target 2000 m away. We also demonstrated simulated leak detection from ranges of 200 m using the 25 cm optical receiver without the fiber amplifier.

  11. Secondary containment and leak detection: A great marriage

    SciTech Connect

    Geyer, W.B.; Stellmach, W.A.

    1995-04-01

    The past decade has seen a proliferation of sophisticated release detection systems for both underground and aboveground storage tanks. But leak detection alone will not ensure against contamination. The storage tank owner who has to spend $100,000 or more to clean up contaminated soil - and much more if groundwater becomes tainted - could have avoided real headaches by investing in sound secondary containment in addition to leak detection. Combined with release detection devices, secondary containment provides the best insurance for UST owners through containment of the primary tank and its piping. We call this a great marriage between two technologies - and EPA agrees.

  12. Wide-band gas leak imaging detection system using UFPA

    NASA Astrophysics Data System (ADS)

    Jin, Wei-qi; Li, Jia-kun; Dun, Xiong; Jin, Minglei; Wang, Xia

    2014-11-01

    The leakage of toxic or hazardous gases not only pollutes the environment, but also threatens people's lives and property safety. Many countries attach great importance to the rapid and effective gas leak detection technology and instrument development. However, the gas leak imaging detection systems currently existing are generally limited to a narrow-band in Medium Wavelength Infrared (MWIR) or Long Wavelength Infrared (LWIR) cooled focal plane imaging, which is difficult to detect the common kinds of the leaking gases. Besides the costly cooled focal plane array is utilized, the application promotion is severely limited. To address this issue, a wide-band gas leak IR imaging detection system using Uncooled Focal Plane Array (UFPA) detector is proposed, which is composed of wide-band IR optical lens, sub-band filters and switching device, wide-band UFPA detector, video processing and system control circuit. A wide-band (3µm~12µm) UFPA detector is obtained by replacing the protection window and optimizing the structural parameters of the detector. A large relative aperture (F#=0.75) wide-band (3μm~12μm) multispectral IR lens is developed by using the focus compensation method, which combining the thickness of the narrow-band filters. The gas leak IR image quality and the detection sensitivity are improved by using the IR image Non-Uniformity Correction (NUC) technology and Digital Detail Enhancement (DDE) technology. The wide-band gas leak IR imaging detection system using UFPA detector takes full advantage of the wide-band (MWIR&LWIR) response characteristic of the UFPA detector and the digital image processing technology to provide the resulting gas leak video easy to be observed for the human eyes. Many kinds of gases, which are not visible to the naked eyes, can be sensitively detected and visualized. The designed system has many commendable advantages, such as scanning a wide range simultaneously, locating the leaking source quickly, visualizing the gas

  13. Leak before break application in French PWR plants under operation

    SciTech Connect

    Faidy, C.

    1997-04-01

    Practical applications of the leak-before break concept are presently limited in French Pressurized Water Reactors (PWR) compared to Fast Breeder Reactors. Neithertheless, different fracture mechanic demonstrations have been done on different primary, auxiliary and secondary PWR piping systems based on similar requirements that the American NUREG 1061 specifications. The consequences of the success in different demonstrations are still in discussion to be included in the global safety assessment of the plants, such as the consequences on in-service inspections, leak detection systems, support optimization,.... A large research and development program, realized in different co-operative agreements, completes the general approach.

  14. [Leak of anesthetic gases inside the anesthesia machine].

    PubMed

    Tanaka, Tadashi; Masaki, Go; Kato, Hidetaka; Takita, Eiichi; Sugai, Naosuke

    2006-05-01

    We experienced the leak of anesthetic gases inside the anesthesia machine in spite of performing the leak test before its use. After induction of anesthesia, a laryngeal mask airway was inserted and the patient was ventilated manually. At the beginning we could not find any signs of machine troubles. High airway pressure occurred immediately after switching to the mechanical ventilation. Because we could not detect the details of the machine trouble, tidal volume was set lower and the surgery was continued. After surgery, we found a crack in a fresh gas circuit valve. We have to check the anesthesia machine regularly and know its duration of use.

  15. Approach to evaluating leak detection methods in underground storage tanks

    NASA Astrophysics Data System (ADS)

    Starr, J.; Broscious, J.; Niaki, S.

    1986-10-01

    The detection and evaluation of leaks in underground storage tanks require a detailed knowledge of conditions both within the tank and in the nearby surroundings. The test apparatus, as constructed, enables data regarding these environmental conditions to be readily obtained and incorporated in a carefully structured test program that minimizes the amount of costly full-scale testing that would otherwise be required to evaluate volumetric leak detection methods for underground storage tanks. In addition, sufficient flexibility has been designed into the apparatus to enable additional evaluations of non-volumetric test methods to be conducted, and different types of tanks and products to be tested in a cost-effective manner.

  16. Minimally invasive management of anastomotic leaks in colorectal surgery

    PubMed Central

    Sevim, Yusuf; Celik, Suleyman Utku; Yavarifar, Hana; Akyol, Cihangir

    2016-01-01

    Anastomotic leakage is an unfortunate complication of colorectal surgery. This distressing situation can cause severe morbidity and significantly affects the patient’s quality of life. Additional interventions may cause further morbidity and mortality. Parenteral nutrition and temporary diverting ostomy are the standard treatments of anastomotic leaks. However, technological developments in minimally invasive treatment modalities for anastomotic dehiscence have caused them to be used widely. These modalities include laparoscopic repair, endoscopic self-expandable metallic stents, endoscopic clips, over the scope clips, endoanal repair and endoanal sponges. The review aimed to provide an overview of the current knowledge on the minimally invasive management of anastomotic leaks. PMID:27721925

  17. Leak detection by acoustic emissions monitoring: An experimental investigation of the acoustic properties of leaks and the attenuation characteristics of soil

    NASA Astrophysics Data System (ADS)

    Kilpatrick, James F.; March, Patrick A.

    1994-05-01

    This study experimentally explored the conditions, equipment, and methodology necessary for the acoustic detection of small leaks of jet fuel (JP4) from underground storage tank (UST) systems. The study indicates that acoustic leak detection of very small leaks is feasible. In general, significant JP4 fuel leaks which occur across a 5 PSI (pounds per square inch) or greater pressure drop are acoustically active and can be detected with proper sensors and proper placement of sensors. The primary source of leak noise is turbulent flow through the leak orifice. At lower pressures, the leak flow becomes laminar, and the leak becomes virtually silent. With direct transducer contact on the pipe or tank wall and sufficient system pressure, leaks smaller than 0.1 GPH (gallons per hour) can be detected. Larger leaks can be detected through short distances in soil. However, sand, which is the most commonly used fill material for UST systems, provides significant acoustic attenuation. Consequently, waveguides must be used when monitoring distances exceeding about 1 foot of travel through sand. Sand acts to reduce background noise levels, providing an ideal environment for acoustic leak detection using sensors mounted directly on the pipe or tank wall.

  18. The application of capnography to differentiate peri-chest tube air leak from parenchymal leak following pulmonary surgery

    PubMed Central

    Walker, William S.

    2014-01-01

    Prolonged air leak is a common complication of pulmonary resection. However, while a bubbling chest drain is commonly related to parenchymal air leakage, it may also be caused by air entering the pleural cavity via an incomplete seal of the tissues at the chest tube insertion site. Examination alone is not sufficient to guide the surgeon as to which of the above complications is responsible for drain bubbling. We describe a simple method, whereby a CO2 monitoring device is attached to the chest drain to determine whether the air loss observed is in fact due to a pulmonary air leak. PMID:24790853

  19. 40 CFR 63.1255 - Standards: Equipment leaks.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 12 2014-07-01 2014-07-01 false Standards: Equipment leaks. 63.1255 Section 63.1255 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES...

  20. 40 CFR 63.1363 - Standards for equipment leaks.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 12 2014-07-01 2014-07-01 false Standards for equipment leaks. 63.1363 Section 63.1363 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES...

  1. 10 CFR 36.59 - Detection of leaking sources.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... alarm set-point to a higher level if necessary to operate the pool water purification system to clean up... certificate from a transferor that leak test has been done within the 6 months before the transfer. Water from... either by using a radiation monitor on a pool water circulating system or by analysis of a sample of...

  2. 40 CFR 63.1331 - Equipment leak provisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... in pumps and agitator seals in light liquid service shall not be considered to be a leak. For... polymer fluid used to provide lubrication and/or cooling of the pump or agitator shaft exits the pump... by § 63.1335(e)(6). (6) For pumps, valves, connectors, and agitators in heavy liquid...

  3. 40 CFR 63.1331 - Equipment leak provisions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... in pumps and agitator seals in light liquid service shall not be considered to be a leak. For... polymer fluid used to provide lubrication and/or cooling of the pump or agitator shaft exits the pump... by § 63.1335(e)(6). (6) For pumps, valves, connectors, and agitators in heavy liquid...

  4. 40 CFR 63.1331 - Equipment leak provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... in pumps and agitator seals in light liquid service shall not be considered to be a leak. For... polymer fluid used to provide lubrication and/or cooling of the pump or agitator shaft exits the pump... by § 63.1335(e)(6). (6) For pumps, valves, connectors, and agitators in heavy liquid...

  5. Thermal-leak analyzer for vacuum-jacketed lines

    NASA Technical Reports Server (NTRS)

    Heisman, R. M.; Iceland, W. F.; Ruppe, E. P.

    1978-01-01

    Technique involves coating suspected area with water-soluble black paint that gives even, infrared emission. Painted area is warmed with heat gun; an infrared scanner is used to detect cooled spot on jacket exterior. Introduction of atmospheric pressure into jacket intensifies leak jet and improves test sensitivity.

  6. Acoustic leak-detection system for railroad transportation security

    NASA Astrophysics Data System (ADS)

    Womble, P. C.; Spadaro, J.; Harrison, M. A.; Barzilov, A.; Harper, D.; Hopper, L.; Houchins, E.; Lemoff, B.; Martin, R.; McGrath, C.; Moore, R.; Novikov, I.; Paschal, J.; Rogers, S.

    2007-04-01

    Pressurized rail tank cars transport large volumes of volatile liquids and gases throughout the country, much of which is hazardous and/or flammable. These gases, once released in the atmosphere, can wreak havoc with the environment and local populations. We developed a system which can non-intrusively and non-invasively detect and locate pinhole-sized leaks in pressurized rail tank cars using acoustic sensors. The sound waves from a leak are produced by turbulence from the gas leaking to the atmosphere. For example, a 500 μm hole in an air tank pressurized to 689 kPa produces a broad audio frequency spectrum with a peak near 40 kHz. This signal is detectable at 10 meters with a sound pressure level of 25 dB. We are able to locate a leak source using triangulation techniques. The prototype of the system consists of a network of acoustic sensors and is located approximately 10 meters from the center of the rail-line. The prototype has two types of acoustic sensors, each with different narrow frequency response band: 40 kHz and 80 kHz. The prototype is connected to the Internet using WiFi (802.11g) transceiver and can be remotely operated from anywhere in the world. The paper discusses the construction, operation and performance of the system.

  7. 40 CFR 63.148 - Leak inspection provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Leak inspection provisions. 63.148 Section 63.148 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... part 60, appendix A. (4) Calibration gases shall be as follows: (i) Zero air (less than 10 parts...

  8. Locating and sealing air leaks in multiroomed buildings

    NASA Technical Reports Server (NTRS)

    Britton, J. M.

    1968-01-01

    Industrial, nontoxic smoke bombs are used in multiroomed buildings to locate and fill discovered leak areas with polyurethane foam. All obvious air escape routes are sealed and the room is then pressurized to a minimum of 0.1 inch water above the pressure of adjoining rooms.

  9. VOLUMETRIC LEAK DETECTION IN LARGE UNDERGROUND STORAGE TANKS - VOLUME I

    EPA Science Inventory

    A set of experiments was conducted to determine whether volumetric leak detection system presently used to test underground storage tanks (USTs) up to 38,000 L (10,000 gal) in capacity could meet EPA's regulatory standards for tank tightness and automatic tank gauging systems whe...

  10. 10 CFR 36.59 - Detection of leaking sources.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... alarm set-point to a higher level if necessary to operate the pool water purification system to clean up... certificate from a transferor that leak test has been done within the 6 months before the transfer. Water from... either by using a radiation monitor on a pool water circulating system or by analysis of a sample of...

  11. 10 CFR 36.59 - Detection of leaking sources.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... alarm set-point to a higher level if necessary to operate the pool water purification system to clean up... certificate from a transferor that leak test has been done within the 6 months before the transfer. Water from... either by using a radiation monitor on a pool water circulating system or by analysis of a sample of...

  12. 10 CFR 36.59 - Detection of leaking sources.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... alarm set-point to a higher level if necessary to operate the pool water purification system to clean up... certificate from a transferor that leak test has been done within the 6 months before the transfer. Water from... either by using a radiation monitor on a pool water circulating system or by analysis of a sample of...

  13. 10 CFR 36.59 - Detection of leaking sources.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... alarm set-point to a higher level if necessary to operate the pool water purification system to clean up... certificate from a transferor that leak test has been done within the 6 months before the transfer. Water from... either by using a radiation monitor on a pool water circulating system or by analysis of a sample of...

  14. 84. Photocopied August 1978. REPAIRING FOREBAY LEAK, NOVEMBER 1907. THE ...

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

    84. Photocopied August 1978. REPAIRING FOREBAY LEAK, NOVEMBER 1907. THE PILE-DRIVER IS DRIVING NEW PILES FOR THE FOREBAY APRON, CLAY BACKFILL AND PLANKING CREWS ARE BUSY AT THE RIGHT. MUCH OF THE FOREBAY FLOOR WAS ALSO REPLANKED AT THIS TIME. (520) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

  15. COPPER PITTING CORROSION AND PINHOLE LEAKS: A CASE STUDY

    EPA Science Inventory

    Localized corrosion, or "pitting", of copper drinking water pipe continues is a problem for many water utilities and their customers. Extreme attack leads to pinhole leaks that can potentially lead to water damage, mold growth, and costly repairs for the homeowners, as well as th...

  16. Valve leak detection for maintenance and thermal performance

    SciTech Connect

    Dimmick, J.G.; Mills, W.H.

    1988-01-01

    The theory and practical applications of the acoustic valve leak analyzer (AVLA) are discussed in this paper. Test procedures, analysis techniques, limitations, and results are presented, along with several case histories. It also presents information on check valve applications, which are routine for marine steam plants, but only recently of interest to utility engineers.

  17. Low-Leak, High-Flow Poppet Valve

    NASA Technical Reports Server (NTRS)

    Tervo, John N.

    1995-01-01

    Valve with conical poppet modified to incorporate smooth transition to segment of sphere at upstream end of cone. Constitutes sealing surface of poppet; results in leak rate equivalent to ball-type poppet, and extremely low flow losses. Also enables use of loose fit for guiding poppet, with resulting lower manufacturing cost, high reliability, and long operating life.

  18. Scrape on Endeavour's robotic arm during oxygen leak repairs

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- Robotic arm experts begin inspection of a scrape on the surface of the honeycomb shell on Endeavour's robotic arm. The scrape occurred while work platforms were being installed to gain access to repair the oxygen leak in the Shuttle's mid-body. Launch of Endeavour on mission STS-113 has been postponed until no earlier than Nov. 22.

  19. Scrape on Endeavour's robotic arm during oxygen leak repairs

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- Robotic arm experts get ready for ultrasound testing on Endeavour's robotic arm. A scrape of the honeycomb shell around the arm occurred while work platforms were being installed to gain access to repair the oxygen leak in the Shuttle's mid-body. Launch of Endeavour on mission STS-113 has been postponed until no earlier than Nov. 22.

  20. Scrape on Endeavour's robotic arm during oxygen leak repairs

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- A piece of the honeycomb shell around Endeavour's robotic arm has been cut to inspect the arm. A scrape of the shell occurred while work platforms were being installed to gain access to repair the oxygen leak in the Shuttle's mid-body. Launch of Endeavour on mission STS-113 has been postponed until no earlier than Nov. 22.

  1. Scrape on Endeavour's robotic arm during oxygen leak repairs

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- Robotic arm experts begin inspection of a scrape on the surface of the honeycomb shell on Endeavour's robotic arm. The scrape occurred while work platforms were being installed to gain access to repair the oxygen leak in the Shuttle's mid-body. Launch of Endeavour on mission STS-113 has been postponed until no earlier than Nov. 22..

  2. A Hydrazine Leak Sensor Based on Chemically Reactive Thermistors

    NASA Technical Reports Server (NTRS)

    Davis, Dennis D.; Mast, Dion J.; Baker, David L.

    1999-01-01

    Leaks in the hydrazine supply system of the Shuttle APU can result in hydrazine ignition and fire in the aft compartment of the Shuttle. Indication of the location of a leak could provide valuable information required for operational decisions. WSTF has developed a small, single use sensor for detection of hydrazine leaks. The sensor is composed of a thermistor bead coated with copper(II) oxide (CuO) dispersed in a clay or alumina binder. The CuO-coated thermistor is one of a pair of closely located thermistors, the other being a reference. On exposure to hydrazine the CuO reacts exothermically with the hydrazine and increases the temperature of the coated-thermistor by several degrees. The temperature rise is sensed by a resistive bridge circuit and an alarm registered by data acquisition software. Responses of this sensor to humidity changes, hydrazine concentration, binder characteristics, distance from a liquid leak, and ambient pressure levels as well as application of this sensor concept to other fluids are presented.

  3. 40 CFR 63.1255 - Standards: Equipment leaks.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) General equipment leak requirements. (1) The provisions of this section apply to pumps, compressors... connection systems. Section 63.169 applies to pumps, valves, connectors, and agitators in heavy liquid... or operator may not comply with the planned routine maintenance provisions in § 63.1252(h)....

  4. Monitoring plan for characterization of the Building 3019 leak site

    SciTech Connect

    Not Available

    1986-06-01

    The Oak Ridge National Laboratory (ORNL) has established a Remedial Action Program to provide comprehensive management of areas where past research, development, and waste management activities have resulted in residual contamination of facilities or the environment. In the winter of 1985, elevated levels of strontium-90 were detected in White Oak Creek and the ORNL sewage treatment plant. A leak was subsequently identified in a low-level waste transfer line north of Building 3019. The period of leakage and the exact chemical composition of the effluent are unknown. Two dye tests conducted at the leak site have identified several possible pathways for contaminant migration. The discovery of a solution cavity in the Chickamauga bedrock underlying the leak site and the rapid appearance of dye in the sump at Building 3042 indicate the extension of the cavity system along strike to the east. This report outlines the available published and unpublished background information pertaining to the site and proposes a monitoring plan consisting of soil sample collection and monitor well installation to provide a preliminary assessment of the types and extent of contamination at the leak site. The plan is also designed to provide additional geologic and hydrologic data for evaluating possible contaminant migration pathways. 6 refs., 10 figs., 1 tab.

  5. Leaks, Lumps, and Lines: Stigma and Women's Bodies

    ERIC Educational Resources Information Center

    Chrisler, Joan C.

    2011-01-01

    Women's bodies have often been positioned in art and popular culture as monstrous or defiled and women's bodily products (e.g., menstrual fluid, breast milk) as disgusting. This framing has led to the stigmatization of aspects of women's bodies (e.g., leaking fluids, lumps of fat, and lines in the skin that indicate aging), especially those…

  6. 40 CFR 1065.345 - Vacuum-side leak verification.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ....345 Section 1065.345 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calibrations and Verifications Flow-Related Measurements § 1065...) Measurement principles. A leak may be detected either by measuring a small amount of flow when there should...

  7. Analog Binaural Circuits for Detecting and Locating Leaks

    NASA Technical Reports Server (NTRS)

    Hartley, Frank T.

    2003-01-01

    Very-large-scale integrated (VLSI) analog binaural signal-processing circuits have been proposed for use in detecting and locating leaks that emit noise in the ultrasonic frequency range. These circuits would be designed to function even in the presence of intense lower-frequency background noise that could include sounds associated with flow and pumping. Each of the proposed circuits would include the approximate electronic equivalent of a right and a left cochlea plus correlator circuits. A pair of transducers (microphones or accelerometers), corresponding to right and left ears, would provide the inputs to their respective cochleas from different locations (e.g., from different positions along a pipe). The correlation circuits plus some additional external circuits would determine the difference between the times of arrival of a common leak sound at the two transducers. Then the distance along the pipe from either transducer to the leak could be estimated from the time difference and the speed of sound along the pipe. If three or more pairs of transducers and cochlear/correlator circuits were available and could suitably be positioned, it should be possible to locate a leak in three dimensions by use of sound propagating through air.

  8. DETAIL OF JAMES LEAK CONFEDERATE HEADSTONE (RIGHT FOREGROUND), WITH CANNON, ...

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

    DETAIL OF JAMES LEAK CONFEDERATE HEADSTONE (RIGHT FOREGROUND), WITH CANNON, FLAGPOLE, CONFEDERATE MONUMENT, CANNONBALL PYRAMID AND ARC OF UNKNOWN U.S. SOLDIER HEADSTONES IN BACKGROUND. VIEW TO NORTHEAST. - Oak Woods Cemetery, Confederate Mound, 1035 East 67th Street, Chicago, Cook County, IL

  9. 40 CFR 63.148 - Leak inspection provisions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... readings for background. If an owner or operator elects to not adjust readings for background, all such... is a leak. If an owner or operator elects to adjust instrument readings for background, the owner or operator shall measure background concentration using the procedures in §§ 63.180(b) and (c) of subpart...

  10. 40 CFR 63.148 - Leak inspection provisions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... readings for background. If an owner or operator elects to not adjust readings for background, all such... is a leak. If an owner or operator elects to adjust instrument readings for background, the owner or operator shall measure background concentration using the procedures in §§ 63.180(b) and (c) of subpart...

  11. 40 CFR 63.148 - Leak inspection provisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... readings for background. If an owner or operator elects to not adjust readings for background, all such... is a leak. If an owner or operator elects to adjust instrument readings for background, the owner or operator shall measure background concentration using the procedures in §§ 63.180(b) and (c) of subpart...

  12. 40 CFR 63.148 - Leak inspection provisions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... readings for background. If an owner or operator elects to not adjust readings for background, all such... is a leak. If an owner or operator elects to adjust instrument readings for background, the owner or operator shall measure background concentration using the procedures in §§ 63.180(b) and (c) of subpart...

  13. Management of Prolonged Pulmonary Air Leaks With Endobronchial Valve Placement

    PubMed Central

    Doelken, Peter; Pupovac, Stevan; Ata, Ashar; Fabian, Tom

    2016-01-01

    Background: Prolonged pulmonary air leaks (PALs) are associated with increased morbidity and extended hospital stay. We sought to investigate the role of bronchoscopic placement of 1-way valves in treating this condition. Methods: We queried a prospectively maintained database of patients with PAL lasting more than 7 days at a tertiary medical center. Main outcome measures included duration of chest tube placement and hospital stay before and after valve deployment. Results: Sixteen patients were eligible to be enrolled from September 2012 through December 2014. One patient refused to give consent, and in 4 patients, the source of air leak could not be identified with bronchoscopic balloon occlusion. Eleven patients (9 men; mean age, 65 ± 15 years) underwent bronchoscopic valve deployment. Eight patients had postoperative PAL and 3 had a secondary spontaneous pneumothorax. The mean duration of air leak before valve deployment was 16 ± 12 days, and the mean number of implanted valves was 1.9 (median, 2). Mean duration of hospital stay before and after valve deployment was 18 and 9 days, respectively (P = .03). Patients who had more than a 50% decrease in air leak on digital monitoring had the thoracostomy tube removed within 3–6 days. There were no procedural complications related to deployment or removal of the valves. Conclusions: Bronchoscopic placement of 1-way valves is a safe procedure that could help manage patients with prolonged PAL. A prospective randomized trial with cost-efficiency analysis is necessary to better define the role of this bronchoscopic intervention and demonstrate its effect on air leak duration. PMID:27647978

  14. Gastroesophageal stenting for the management of post sleeve gastrectomy leak

    PubMed Central

    Guzaiz, Noha; Arabi, Mohammad; Khankan, Azzam; Salman, Refaat; Al-Toki, Mohammed; Qazi, Shahbaz; Alzakari, Abdulmohsin; Al-Moaiqel, Mohammad

    2016-01-01

    Objectives To retrospectively evaluate the effectiveness of gastroesophageal stenting for post sleeve gastrectomy staple line leaks using removable self-expandable stents. Methods Between April 2012 and June 2015, 12 consecutive patients (6 males) with mean age of 34 years: (21-38 years) presented with staple line leak 1-8 weeks after the operation (mean 2.8 weeks). Patients underwent gastroesophageal stenting by interventional radiology. A total of 23 stents were deployed with mean length of 17.8 cm (7-24 cm) and mean diameter 25.6 mm (18-36 mm). Stent re-insertion was needed in 7 patients (9 procedure), while 6 patients required percutaneous collection drainage and 3 patients required endoscopic glue injection with clipping. Two stent removal procedures were carried out under endoscopic visualization after failed stent capture under fluoroscopy, while the remaining stents were successfully removed by interventional radiology. Results Stent placement was technically successful in all patients. Stent migration occurred in 6 patients (50%). There is a tendency for stent migration with shorter stent length (R= -0.557, p=0.008). The mean duration of stenting was 60.5 days (14-137 days). All patients underwent stent removal and resumed oral intake with no recurrence of leak at a mean follow up time of 190 days (14-410 days). Complications included gastrointestinal bleeding (n=1), proximal esophageal stricture (n=1) and stent occlusion (n=1). Conclusion Gastroesophageal stenting as a primary measure after diagnosis of early post sleeve gastrectomy leak appears to offer a safe and effective alternative option in obviating repeat surgical interventions. Minimally invasive interventions may still be required for the management of persistent leak. PMID:27874149

  15. Leaks in nuclear grade high efficiency aerosol filters

    SciTech Connect

    Scripsick, Ronald Clyde

    1994-07-01

    Nuclear grade high efficiency aerosol filters, also known as high efficiency particulate air (HEPA) filters, are commonly used in air cleaning systems for removal of hazardous aerosols. Performance of the filter units is important in assuring health and environmental protection. The filter units are constructed from pleated packs of fiberglass filter media sealed into rigid frames. Results of previous studies on such filter units indicate that their performance may not be completely predicted by ideal performance of the fibrous filter media. In this study, departure from ideal performance is linked to leaks existing in filter units and overall filter unit performance is derived from independent performance of the individual filter unit components. The performance of 14 nuclear grade HEPA filter units (size 1, 25 cfm) with plywood frames was evaluated with a test system that permitted independent determination of penetration as a function of particle size for the whole filter unit, the filter unit frame, and the filter media pack. Tests were performed using a polydisperse aerosol of di-2-ethylhexyl phthalate with a count median diameter of 0.2 {mu}m and geometric standard deviation of 1.6. Flow rate and differential pressure were controlled from 1% to 100% of design values. Particle counts were made upstream and downstream of the filter unit with an optical particle counter (OPC). The OPC provided count information in 28 size channels over the particle diameter range from 0.1 to 0.7 μm. Results provide evidence for a two component leak model of filler unit performance with: (1) external leaks through filter unit frames, and (2) internal leaks through defects in the media and through the seal between the media pack and frame. For the filter units evaluated, these leaks dominate overall filter unit performance over much of the flow rate and particle size ranges tested.

  16. CSNI specialist meeting on leak-before-break in nuclear reactor piping: proceedings

    SciTech Connect

    Not Available

    1984-08-01

    On September 1 and 2, 1983, the CSNI subcommittee on primary system integrity held a special meeting in Monterey, California, on the subject of leak-before-break in nuclear reactor piping systems. The purpose of the meeting was to provide an international forum for the exchange of ideas, positions, and research results; to identify areas requiring additional research and development; and to determine the general attitude toward acceptance of the leak-before-break concept. The importance of the leak-before-break issue was evidenced by excellent attendance at the meeting and through active participation by the meeting attendees. Approximately 125 people representing fifteen different nations attended the meeting. The meeting was divided into four technical sessions addressing the following areas: Application of Piping Fracture Mechanics to Leak-Before Break, Leak Rate and Leak Detection, Leak-Before-Break Studies, Methods and Results, Current and Proposed Positions on Leak-Before-Break.

  17. Rapid, Vehicle-Based Identification of Location and Magnitude of Urban Natural Gas Pipeline Leaks.

    PubMed

    von Fischer, Joseph C; Cooley, Daniel; Chamberlain, Sam; Gaylord, Adam; Griebenow, Claire J; Hamburg, Steven P; Salo, Jessica; Schumacher, Russ; Theobald, David; Ham, Jay

    2017-04-04

    Information about the location and magnitudes of natural gas (NG) leaks from urban distribution pipelines is important for minimizing greenhouse gas emissions and optimizing investment in pipeline management. To enable rapid collection of such data, we developed a relatively simple method using high-precision methane analyzers in Google Street View cars. Our data indicate that this automated leak survey system can document patterns in leak location and magnitude within and among cities, even without wind data. We found that urban areas with prevalent corrosion-prone distribution lines (Boston, MA, Staten Island, NY, and Syracuse, NY), leaked approximately 25-fold more methane than cities with more modern pipeline materials (Burlington, VT, and Indianapolis, IN). Although this mobile monitoring method produces conservative estimates of leak rates and leak counts, it can still help prioritize both leak repairs and replacement of leak-prone sections of distribution lines, thus minimizing methane emissions over short and long terms.

  18. Method and apparatus for continuous fluid leak monitoring and detection in analytical instruments and instrument systems

    DOEpatents

    Weitz, Karl K.; Moore, Ronald J.

    2010-07-13

    A method and device are disclosed that provide for detection of fluid leaks in analytical instruments and instrument systems. The leak detection device includes a collection tube, a fluid absorbing material, and a circuit that electrically couples to an indicator device. When assembled, the leak detection device detects and monitors for fluid leaks, providing a preselected response in conjunction with the indicator device when contacted by a fluid.

  19. Hanford Double-Shell Tank AY-102 Radioactive Waste Leak Investigation Update

    SciTech Connect

    Washenfelder, Dennis J.

    2015-02-03

    The presentation outline is: Briefly review leak integrity status of tank AY-102 and current leak behavior; Summarize recent initiatives to understand leak mechanism and to verify integrity of remaining waste confinement structures; describe planned waste recovery activities; and, introduce other papers on tank AY-102 topics.

  20. PORTABLE IMAGING DEVICES FOR INDUSTRIAL LEAK DETECTION AT PETROLEUM REFINERIES AND CHEMICAL PLANTS

    EPA Science Inventory

    Undiscovered gas leaks, or fugitive emissions, in chemical plants and refinery operations can impact regional air quality as well as being a public health problem. Surveying a facility for potential gas leaks can be a daunting task. Industrial Leak Detection and Repair (LDAR) pro...

  1. Assessment of Remote Sensing Technologies for Location of Hydrogen and Helium Leaks

    NASA Technical Reports Server (NTRS)

    Sellar, R. Glenn; Wang, Danli

    2000-01-01

    The objective of this initial phase of this research effort is to: 1) Evaluate remote sensing technologies for location of leaks of gaseous molecular hydrogen (H2) and gaseous helium (He) in air, for space transportation applications; and 2) Develop a diffusion model that predicts concentration of H2 or He gas as a function of leak rate and distance from the leak.

  2. 49 CFR 192.717 - Transmission lines: Permanent field repair of leaks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Transmission lines: Permanent field repair of leaks. 192.717 Section 192.717 Transportation Other Regulations Relating to Transportation (Continued... § 192.717 Transmission lines: Permanent field repair of leaks. Each permanent field repair of a leak...

  3. 49 CFR 192.717 - Transmission lines: Permanent field repair of leaks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Transmission lines: Permanent field repair of leaks. 192.717 Section 192.717 Transportation Other Regulations Relating to Transportation (Continued... § 192.717 Transmission lines: Permanent field repair of leaks. Each permanent field repair of a leak...

  4. 49 CFR 192.717 - Transmission lines: Permanent field repair of leaks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Transmission lines: Permanent field repair of leaks. 192.717 Section 192.717 Transportation Other Regulations Relating to Transportation (Continued... § 192.717 Transmission lines: Permanent field repair of leaks. Each permanent field repair of a leak...

  5. Leaking and Death-Threats by Students: A Study in German Schools

    ERIC Educational Resources Information Center

    Bondü, Rebecca; Scheithauer, Herbert

    2014-01-01

    Leaking comprises observable behavior or statements that signal intentions of committing a violent offense and is considered an important warning sign for school shootings. School staff who are confronted with leaking have to assess its seriousness and react appropriately--a difficult task, because knowledge about leaking is sparse. The present…

  6. Hanford Single-Shell Tank Leak Causes and Locations - 241-B Farm

    SciTech Connect

    Girardot, Crystal L.; Harlow, Donald G.

    2013-07-11

    This document identifies 241-B Tank Farm (B Farm) leak cause and locations for the 100 series leaking tank (241-B-107) identified in RPP-RPT-49089, Hanford B-Farm Leak Inventory Assessments Report. This document satisfies the B Farm portion of the target (T04) in the Hanford Federal Facility Agreement and Consent Order milestone M-045-91F.

  7. Method and means of passive detection of leaks in buried pipes

    DOEpatents

    Claytor, T.

    1979-10-30

    A method and means for passive detection of a leak in a buried pipe containing fluid under pressure includes a plurality of acoustic detectors that are placed in contact with the pipe. Noise produced by the leak is detected by the detectors, and the detected signals are correlated to locate the leak. In one embodiment of the invention two detectors are placed at different locations to locate a leak between them. In an alternate embodiment two detectors of different waves are placed at substantially the same location to determine the distance of the leak from the location.

  8. Area Monitoring for Detection of Leaks and/or Flames

    NASA Technical Reports Server (NTRS)

    Mian, Zahid F. (Inventor); Gamache, Ronald W. (Inventor); Glasser, Nick (Inventor)

    2015-01-01

    A solution for monitoring an area for the presence of a flame and/or a leak, such as from a pressurized fluid, is provided. An imaging device can be used that acquires image data based on electromagnetic radiation having wavelengths only corresponding to at least one region of the electromagnetic spectrum in which electromagnetic radiation from an ambient light source is less than the electromagnetic radiation emitted by at least one type of flame for which the presence within the area is being monitored. An acoustic device can be used that is configured to acquire acoustic data for the area and enhance acoustic signals in a range of frequencies corresponding to a leak of a pressurized fluid present in the area.

  9. Massive Cerebrospinal Fluid Leak of the Temporal Bone

    PubMed Central

    Manno, Alessandra; Pasqualitto, Emanuela; Ciofalo, Andrea; Angeletti, Diletta; Pasquariello, Benedetta

    2016-01-01

    Cerebrospinal fluid (CSF) leakage of the temporal bone region is defined as abnormal communications between the subarachnoidal space and the air-containing spaces of the temporal bone. CSF leak remains one of the most frequent complications after VS surgery. Radiotherapy is considered a predisposing factor for development of temporal bone CSF leak because it may impair dural repair mechanisms, thus causing inadequate dural sealing. The authors describe the case of a 47-year-old man with a massive effusion of CSF which extended from the posterior and lateral skull base to the first cervical vertebrae; this complication appeared after a partial enucleation of a vestibular schwannoma (VS) with subsequent radiation treatment and second operation with total VS resection. PMID:27597915

  10. Massive Cerebrospinal Fluid Leak of the Temporal Bone.

    PubMed

    Iannella, Giannicola; Manno, Alessandra; Pasqualitto, Emanuela; Ciofalo, Andrea; Angeletti, Diletta; Pasquariello, Benedetta; Magliulo, Giuseppe

    2016-01-01

    Cerebrospinal fluid (CSF) leakage of the temporal bone region is defined as abnormal communications between the subarachnoidal space and the air-containing spaces of the temporal bone. CSF leak remains one of the most frequent complications after VS surgery. Radiotherapy is considered a predisposing factor for development of temporal bone CSF leak because it may impair dural repair mechanisms, thus causing inadequate dural sealing. The authors describe the case of a 47-year-old man with a massive effusion of CSF which extended from the posterior and lateral skull base to the first cervical vertebrae; this complication appeared after a partial enucleation of a vestibular schwannoma (VS) with subsequent radiation treatment and second operation with total VS resection.

  11. Troponin leak associated with drug-induced methemoglobinemia.

    PubMed

    Cannon, Robert D; Wagner, Michael; Jacoby, Jeanne L

    2014-10-01

    Drug-induced methemoglobinemia is a well-described entity but has not been previously associated with elevated troponins in the absence of cardiac symptoms. We report a case of a patient presenting to the emergency department (ED) with complaints related to an exacerbation of her long-standing cystitis. A low pulse oximetry reading prompted an evaluation, revealing a troponin leak, which peaked at 10 hours. Her methemoglobin level was found to be elevated at 11.4%, but a preexisting anemia apparently prevented the clinical recognition of cyanosis. The methemoglobinemia was determined to be secondary to her ingestion of phenazopyridine and trimethoprim-sulfa methoxizole. Although phenazopyridine and sulfa agents have long been known to cause methemoglobinemia, our patient exhibited an asymptomatic troponin leak that has not been previously reported as a complication of drug-induced methemoglobinemia. Clinicians should be aware of this potential association.

  12. MCO combustible gas management leak test acceptance criteria

    SciTech Connect

    SHERRELL, D.L.

    1999-05-11

    Existing leak test acceptance criteria for mechanically sealed and weld sealed multi-canister overpacks (MCO) were evaluated to ensure that MCOs can be handled and stored in stagnant air without compromising the Spent Nuclear Fuel Project's overall strategy to prevent accumulation of combustible gas mixtures within MCO's or within their surroundings. The document concludes that the integrated leak test acceptance criteria for mechanically sealed and weld sealed MCOs (1 x 10{sup -5} std cc/sec and 1 x 10{sup -7} std cc/sec, respectively) are adequate to meet all current and foreseeable needs of the project, including capability to demonstrate compliance with the NFPA 60 Paragraph 3-3 requirement to maintain hydrogen concentrations [within the air atmosphere CSB tubes] t or below 1 vol% (i.e., at or below 25% of the LFL).

  13. Spacecraft Leak Location Using Structure-Borne Noise

    NASA Astrophysics Data System (ADS)

    Reusser, R. S.; Chimenti, D. E.; Holland, S. D.; Roberts, R. A.

    2010-02-01

    Guided ultrasonic waves, generated by air escaping through a small hole, have been measured with an 8×8 piezoelectric phased-array detector. Rapid location of air leaks in a spacecraft skin, caused by high-speed collisions with small objects, is essential for astronaut survival. Cross correlation of all 64 elements, one pair at a time, on a diced PZT disc combined with synthetic aperture analysis determines the dominant direction of wave propagation. The leak location is triangulated by combining data from two or more detector. To optimize the frequency band selection for the most robust direction finding, noise-field measurements of a plate with integral stiffeners have been performed using laser Doppler velocimetry. We compare optical and acoustic measurements to analyze the influence of the PZT array detector and its mechanical coupling to the plate.

  14. Method for HEPA filter leak scanning with differentiating aerosol detector

    SciTech Connect

    Kovach, B.J.; Banks, E.M.; Wikoff, W.O.

    1997-08-01

    While scanning HEPA filters for leaks with {open_quotes}Off the Shelf{close_quote} aerosol detection equipment, the operator`s scanning speed is limited by the time constant and threshold sensitivity of the detector. This is based on detection of the aerosol density, where the maximum signal is achieved when the scanning probe resides over the pinhole longer than several detector time-constants. Since the differential value of the changing signal can be determined by observing only the first small fraction of the rising signal, using a differentiating amplifier will speed up the locating process. The other advantage of differentiation is that slow signal drift or zero offset will not interfere with the process of locating the leak, since they are not detected. A scanning hand-probe attachable to any NUCON{reg_sign} Aerosol Detector displaying the combination of both aerosol density and differentiated signal was designed. 3 refs., 1 fig.

  15. Management of Leaks in Hydrogen Production, Delivery, and Storage Systems

    SciTech Connect

    Rawls, G

    2006-04-27

    A systematic approach to manage hydrogen leakage from components is presented. Methods to evaluate the quantity of hydrogen leakage and permeation from a system are provided by calculation and testing sensitivities. The following technology components of a leak management program are described: (1) Methods to evaluate hydrogen gas loss through leaks; (2) Methods to calculate opening areas of crack like defects; (3) Permeation of hydrogen through metallic piping; (4) Code requirements for acceptable flammability limits; (5) Methods to detect flammable gas; (6) Requirements for adequate ventilation in the vicinity of the hydrogen system; (7) Methods to calculate dilution air requirements for flammable gas mixtures; and (8) Concepts for reduced leakage component selection and permeation barriers.

  16. Develop Efficient Leak Proof M1 Abrams Plenum Seal

    DTIC Science & Technology

    2014-05-07

    SBIR report, M1 Abrams, plenum seal, turbine blade wear, FOD leakage, turbine failure, air cleaner plenum box, seal design, efficient leak proof seal...premature and excessive turbine blade wear. This in turn leads to a reduced time interval between turbine rebuilds and an estimated $3-$4 million in...Comparison – As drawn vs. actual installation ........................................... 9 Figure 5: Assembly model of M1 Turbine and related components

  17. Passive Leak Detection Using Commercial Hydrogen Colorimetric Indicator

    SciTech Connect

    Hartmann, Kevin; Buttner, William; Burgess, Robert; Rivkin, Carl

    2016-09-01

    Element One, Inc. (www.elem.com), a small business with in Boulder, CO, has been developing hydrogen detection technology based upon a highly selective colorimetric indicator. In its native state, the indicator pigment is a pale gray color, but becomes black upon exposure to hydrogen. The colorimetric change can be readily observed by the naked eye without the need for supplemental electronics or other hardware. Recently, the colorimetric indicator was integrated into a pliable, self-adhesive tape that can readily wrap around pneumatic fittings to serve as a hydrogen leak detector. A prototype version of the Element One indicator tape was tested within an NREL hydrogen system and successfully identified the unexpected presence of a small leak; a summary document for this case study is presented in Appendix 1. The tape was subsequently configured into 10-foot rolls as a product prototype that has just recently been commercialized and marketed under the tradename DetecTape(R). Figure 1 shows the commercial version of DetecTape along with an indicator sample in its native state and one that had been exposed to hydrogen. DetecTape is a self-adhesive silicone-based tape impregnated with a proprietary hydrogen-sensitive indicator based on transition metal oxides. A length of the tape can be cut from the roll and stretched by a factor of two or three times around a fitting. Due to the self-adhesive property of the tape, this provides a tight seal around the fitting. The seal is not hermetic, and is not intended to prevent the release of a leaking gas. However, a portion of the hydrogen leaking from a wrapped fitting will pass through the tape and react with the active indicator impregnated within the tape, thereby inducing blackening.

  18. Leak Location in Plates Using Spatial Fourier Transform Based Analysis

    NASA Astrophysics Data System (ADS)

    Roberts, R.; Holland, S.; Strei, M.; Song, J.; Chimenti, D. E.

    2005-04-01

    The location of air leaks in plate-like structures is examined using a spatial Fourier transform based analysis. Noise data is collected over 2-D spatial arrays at sensor locations, from which mean cross-correlations are compiled. Propagation properties, transit times, and energy distribution among modes are extracted through spatial Fourier transformation of these data. A simple algorithm to determine source location using a reduced set of transform data is demonstrated experimentally, based upon extraction of energy propagation direction.

  19. Scrape on Endeavour's robotic arm during oxygen leak repairs

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- An ultrasound device is held at the site where the honeycomb shell around Endeavour's robotic arm has been cut to inspect the arm. A scrape of the shell occurred while work platforms were being installed to gain access to repair the oxygen leak in the Shuttle's mid-body. Launch of Endeavour on mission STS-113 has been postponed until no earlier than Nov. 22.

  20. Scrape on Endeavour's robotic arm during oxygen leak repairs

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- One of a team of robotic experts looks at the site of the scrape on the surface of the honeycomb shell on the robotic arm that occurred while work platforms were being installed to gain access to repair the oxygen leak in the Shuttle's mid-body. The site will be cut out and ultrasound testing will be done on the structure underneath. Launch of Endeavour on mission STS-113 has been postponed until no earlier than Nov. 22.

  1. Scrape on Endeavour's robotic arm during oxygen leak repairs

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- Workers in Endeavour's payload bay look at the site of the scrape on the surface of the honeycomb shell on the robotic arm that occurred while work platforms were being installed to gain access to repair the oxygen leak in the Shuttle's mid-body. The site will be cut out and ultrasound testing will be done on the structure underneath. Launch of Endeavour on mission STS-113 has been postponed until no earlier than Nov. 22.

  2. Scrape on Endeavour's robotic arm during oxygen leak repairs

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- The site being identified in the photo is the scrape on the surface of the honeycomb shell on Endeavour's robotic arm. The scrape occurred while work platforms were being installed to gain access to repair the oxygen leak in the Shuttle's mid-body. The site will be cut out and ultrasound testing will be done on the structure underneath. Launch of Endeavour on mission STS-113 has been postponed until no earlier than Nov. 22.

  3. Scrape on Endeavour's robotic arm during oxygen leak repairs

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- The opening shown here is the site where the honeycomb shell around Endeavour's robotic arm has been cut to inspect the arm. A scrape of the shell occurred while work platforms were being installed to gain access to repair the oxygen leak in the Shuttle's mid-body. Launch of Endeavour on mission STS-113 has been postponed until no earlier than Nov. 22.

  4. Scrape on Endeavour's robotic arm during oxygen leak repairs

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- One of a team of robotic experts prepares the site scraped on the robotic arm for removal. The scrape occurred while work platforms were being installed to gain access to repair the oxygen leak in the Shuttle's mid-body. The site will be cut out and ultrasound testing will be done on the structure underneath. Launch of Endeavour on mission STS-113 has been postponed until no earlier than Nov. 22.

  5. Scrape on Endeavour's robotic arm during oxygen leak repairs

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- One of a team of robotic experts looks at the site of the scrape on the surface of the the robotic arm's honeycomb shell. The scrape occurred while work platforms were being installed to gain access to repair the oxygen leak in Endeavour's mid-body. The site will be cut out and ultrasound testing will be done on the structure underneath. Launch of Endeavour on mission STS-113 has been postponed until no earlier than Nov. 22.

  6. 105-KE Isolation Barrier Leak Rate Acceptance Test Report

    SciTech Connect

    McCracken, K.J.

    1995-06-14

    This Acceptance Test Report (ATR) contains the completed and signed Acceptance Procedure (ATP) for the 105-KE Isolations Barrier Leak Rate Test. The Test Engineer`s log, the completed sections of the ATP in the Appendix for Repeat Testing (Appendix K), the approved WHC J-7s (Appendix H), the data logger files (Appendices T and U), and the post test calibration checks (Appendix V) are included.

  7. ACOUSTIC LOCATION OF LEAKS IN PRESSURIZED UNDER- GROUND PETROLEUM PIPELINES

    EPA Science Inventory

    Experiments were conducted at the Underground Storage Tank (UST) Test Apparatus Pipeline in which three acoustic sensors separated by a maximum distance of 38.1 m (125 ft) were used to monitor signals produced by 11.4-, 5.7-, and 3.8-L/h (3.0-, 1.5-, and 1.0-gal/h) leaks in th...

  8. Leak Detection by Acoustic Emission Monitoring. Phase 1. Feasibility Study

    DTIC Science & Technology

    1994-05-26

    considered the soil composition- and structure , the leak depth and rate, the acoustic array geometry on the 12 PHASE I 03 SflAIASTrNAflc C’ 111 ATON 90111...First Conference on Acoustic Emission/ Microseismic Activilty in Geologic Structures and Materials. H.R. Hardy, Jr. and F.W. Leighton, 2ditors. Trans...Recognition and Acoustical Imaging , Newport Beach, California, February 4-6. 1987. 29. M.C. Junger and D. Feit. Sounds, Structures , and Their Interaction, The

  9. Broadband reflectance spectroscopy for establishing a quantitative metric of vascular leak using the Miles assay

    NASA Astrophysics Data System (ADS)

    McMurdy, John; Reichner, Jonathan; Mathews, Zara; Markey, Mary; Intwala, Sunny; Crawford, Gregory

    2009-09-01

    Monitoring the physiological effects of biological mediators on vascular permeability is important for identifying potential targets for antivascular leak therapy. This therapy is relevant to treatments for pulmonary edema and other disorders. Current methods of quantifying vascular leak are in vitro and do not allow repeated measurement of the same animal. Using an in vivo diffuse reflectance optical method allows pharmacokinetic analysis of candidate antileak molecules. Here, vascular leak is assessed in mice and rats by using the Miles assay and introducing irritation both topically using mustard oil and intradermally using vascular endothelial growth factor (VEGF). The severity of the leak is assessed using broadband diffuse reflectance spectroscopy with a fiber reflectance probe. Postprocessing techniques are applied to extract an artificial quantitative metric of leak from reflectance spectra at vascular leak sites on the skin of the animal. This leak metric is calculated with respect to elapsed time from irritation in both mustard oil and VEGF treatments on mice and VEGF treatments on rats, showing a repeatable increase in leak metric with leak severity. Furthermore, effects of pressure on the leak metric are observed to have minimal effect on the reflectance spectra, while spatial positioning showed spatially nonuniform leak sites.

  10. An improved PCA method with application to boiler leak detection.

    PubMed

    Sun, Xi; Marquez, Horacio J; Chen, Tongwen; Riaz, Muhammad

    2005-07-01

    Principal component analysis (PCA) is a popular fault detection technique. It has been widely used in process industries, especially in the chemical industry. In industrial applications, achieving a sensitive system capable of detecting incipient faults, which maintains the false alarm rate to a minimum, is a crucial issue. Although a lot of research has been focused on these issues for PCA-based fault detection and diagnosis methods, sensitivity of the fault detection scheme versus false alarm rate continues to be an important issue. In this paper, an improved PCA method is proposed to address this problem. In this method, a new data preprocessing scheme and a new fault detection scheme designed for Hotelling's T2 as well as the squared prediction error are developed. A dynamic PCA model is also developed for boiler leak detection. This new method is applied to boiler water/steam leak detection with real data from Syncrude Canada's utility plant in Fort McMurray, Canada. Our results demonstrate that the proposed method can effectively reduce false alarm rate, provide effective and correct leak alarms, and give early warning to operators.

  11. MWTF jumper connector integral seal block development and leak testing

    SciTech Connect

    Ruff, E.S.; Jordan, S.R.

    1995-01-01

    In fiscal year 1993, tests of an o-ring/tetraseal retainer designed to replace a gasket-type seal used in PUREX-type process jumper connectors encouraged the design of an improved seal block. This new seal block combines several parts into one unitized component called an integral seal block. This report summarizes development and leak testing of the new integral seal block. The integral seal block uses a standard o-ring nested in a groove to accomplish leak tightness. This seal block eliminates the need to machine acme threads into the lower skirt casting and seal retainers, eliminates tolerance stack-up, reduces parts inventory, and eliminates an unnecessary leak path in the jumper connector assembly. This report also includes test data on various types of o-ring materials subjected to heat and pressure. Materials tested included Viton, Kalrez, and fluorosilicone, with some incidental data on teflon coated silicone o-rings. Test experience clearly demonstrates the need to test each seal material for temperature and pressure in its intended application. Some materials advertised as being {open_quotes}better{close_quotes} at higher temperatures did not perform up to expectations. Inspection of the fluorosilicone and Kalrez seals after thermal testing indicates that they are much more susceptible to heat softening than Viton.

  12. A voice-actuated wind tunnel model leak checking system

    NASA Technical Reports Server (NTRS)

    Larson, William E.

    1989-01-01

    A computer program has been developed that improves the efficiency of wind tunnel model leak checking. The program uses a voice recognition unit to relay a technician's commands to the computer. The computer, after receiving a command, can respond to the technician via a voice response unit. Information about the model pressure orifice being checked is displayed on a gas-plasma terminal. On command, the program records up to 30 seconds of pressure data. After the recording is complete, the raw data and a straight line fit of the data are plotted on the terminal. This allows the technician to make a decision on the integrity of the orifice being checked. All results of the leak check program are stored in a database file that can be listed on the line printer for record keeping purposes or displayed on the terminal to help the technician find unchecked orifices. This program allows one technician to check a model for leaks instead of the two or three previously required.

  13. Monitoring plan for characterization of the Building 3028 leak site

    SciTech Connect

    Not Available

    1986-06-01

    The Oak Ridge National Laboratory (ORNL) has established a Remedial Action Program to characterize, manage, and restore areas where past use has resulted in residual contamination of facilities or the environment. In March of 1985, a leak was discovered in the low-level waste (LLW) line leading from Building 3028 during excavation for the construction of condensate traps in the line. Radiation readings as high as 200 R/hr were measured in the contaminated soil in contact with the pipeline. A dye test conducted on the suspect section of line indicated the presence of the leak underneath the southeast corner of the building. The line at that point serves both Building 3028 and Building 3047. A wide variety of radionuclides are processed or produced in the hot cells of Building 3047. All available published and unpublished background information on contaminant inventory, geology, hydrology, and ecology of the site is presented in this report. A monitoring plan is proposed to provide a preliminary assessment of the extent of contamination at the leak site and to provide additional geologic and hydrologic data for evaluating possible contaminant migration pathways.

  14. Optoelectronic leak detection system for monitoring subsea structures

    NASA Astrophysics Data System (ADS)

    Moodie, D.,; Costello, L.; McStay, D.

    2010-04-01

    Leak detection and monitoring on subsea structures is an area of increasing interest for the detection and monitoring of production and control fluids for the oil and gas industry. Current techniques such as capacitive (dielectric) based measurement or passive acoustic systems have limitations and we report here an optoelectronic solution based upon fluorescence spectroscopy to provide a permanent monitoring solution. We report here a new class of optoelectronic subsea sensor for permanent, real time monitoring of hydrocarbon production systems. The system is capable of detecting small leaks of production or hydraulic fluid (ppm levels) over distances of 4-5 meters in a subsea environment. Ideally systems designed for such applications should be capable of working at depths of up to 3000m unattended for periods of 20+ years. The system uses advanced single emitter LED technology to meet the challenges of lifetime, power consumption, spatial coverage and delivery of a cost effective solution. The system is designed for permanent deployment on Christmas tree (XT), subsea processing systems (SPS) and associated equipment to provide enhanced leak detection capability.

  15. Electrical detection of liquid lithium leaks from pipe jointsa)

    NASA Astrophysics Data System (ADS)

    Schwartz, J. A.; Jaworski, M. A.; Mehl, J.; Kaita, R.; Mozulay, R.

    2014-11-01

    A test stand for flowing liquid lithium is under construction at Princeton Plasma Physics Laboratory. As liquid lithium reacts with atmospheric gases and water, an electrical interlock system for detecting leaks and safely shutting down the apparatus has been constructed. A defense in depth strategy is taken to minimize the risk and impact of potential leaks. Each demountable joint is diagnosed with a cylindrical copper shell electrically isolated from the loop. By monitoring the electrical resistance between the pipe and the copper shell, a leak of (conductive) liquid lithium can be detected. Any resistance of less than 2 kΩ trips a relay, shutting off power to the heaters and pump. The system has been successfully tested with liquid gallium as a surrogate liquid metal. The circuit features an extensible number of channels to allow for future expansion of the loop. To ease diagnosis of faults, the status of each channel is shown with an analog front panel LED, and monitored and logged digitally by LabVIEW.

  16. Underground storage tank (UST) monitoring systems for leak detection

    SciTech Connect

    Porter, A.D.

    1995-12-31

    Owners and operators of fuel underground storage tanks (USTs) have had to comply with federal regulations for leak detection since 1988. These regulations were based on data obtained from all areas of the country. Many of these tank systems were steel in corrosive environments. Corrosion was the predominant failure mode. Initially, the attention of UST operators, leak detection systems manufacturers and service providers focused exclusively on compliance. Systems were developed that were expensive and complex, causing many operators to delay compliance until the last possible moment. While most approved leak detection methods continue to perform only this compliance function, there is clearly one exception--automatic tank gauges (ATGs). ATGs have evolved from a single-function, compliance-only system into a multi-tasking, multi-functional management tool that goes far beyond regulatory compliance. The continuing advancement in technology of these multi-functional systems promises to bring cathodic protection, among other functions, under their umbrella in a fully-integrated regulatory compliance and tank management system. The hub of a total site-control system, that ultimately brings together all devices and daily business management functions, will be the on-site computer.

  17. Electrical detection of liquid lithium leaks from pipe joints

    SciTech Connect

    Schwartz, J. A. Jaworski, M. A.; Mehl, J.; Kaita, R.; Mozulay, R.

    2014-11-15

    A test stand for flowing liquid lithium is under construction at Princeton Plasma Physics Laboratory. As liquid lithium reacts with atmospheric gases and water, an electrical interlock system for detecting leaks and safely shutting down the apparatus has been constructed. A defense in depth strategy is taken to minimize the risk and impact of potential leaks. Each demountable joint is diagnosed with a cylindrical copper shell electrically isolated from the loop. By monitoring the electrical resistance between the pipe and the copper shell, a leak of (conductive) liquid lithium can be detected. Any resistance of less than 2 kΩ trips a relay, shutting off power to the heaters and pump. The system has been successfully tested with liquid gallium as a surrogate liquid metal. The circuit features an extensible number of channels to allow for future expansion of the loop. To ease diagnosis of faults, the status of each channel is shown with an analog front panel LED, and monitored and logged digitally by LabVIEW.

  18. Leak injection/detection input for B and W prototype steam generator test request

    SciTech Connect

    1980-11-18

    The goal of the leak injection/detection phase of the test program on the prototype steam generator is to obtain data that can be used to specify the leak protection system for the plant unit steam generators. Both chemical and two acoustic leak detection methods (by GE and Rockwell International) are to be considered. The chemical system has been selected as the reference based on its more developed state. The acoustic methods have potential both as small leak detection systems and as intermediate leak protection/automatic shutdown systems. Simulated leak injections will be made at various locations within the steam generator to determine the performance of the chemical system as specifically applied to the B and W helical coil steam generator geometry. Acoustic tests will be made to characterize the various steam generator background noise sources and to record acoustic signals during smulated leak injections, in order to predict the performance of both systems.

  19. With long, dry summer looming, EPA urges Northwest residents to stop drips and leaks during Fix-a-Leak Week, March 16-23

    EPA Pesticide Factsheets

    (Seattle, WA - March 16, 2015) With local snowpack at historic lows, the U.S. Environmental Protection Agency is inviting Northwest households to make every drop count for Fix-a-Leak Week, March 16 - 23, 2015. The Agency estimates that household leaks wa

  20. 40 CFR 265.196 - Response to leaks or spills and disposition of leaking or unfit-for-use tank systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... leaks or spills and disposition of leaking or unfit-for-use tank systems. A tank system or secondary... hazardous waste into the tank system or secondary containment system and inspect the system to determine the cause of the release. (b) Removal of waste from tank system or secondary containment system. (1) If...

  1. 40 CFR 61.243-2 - Alternative standards for valves in VHAP service-skip period leak detection and repair.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... VHAP service-skip period leak detection and repair. 61.243-2 Section 61.243-2 Protection of Environment... Alternative standards for valves in VHAP service—skip period leak detection and repair. (a)(1) An owner or.... (2) After 2 consecutive quarterly leak detection periods with the percentage of valves leaking...

  2. Leak testing of IR sensor dewars to 1E-15 std He/s

    NASA Astrophysics Data System (ADS)

    Sasaki, Y. Tito; Bergquist, Lyle E.

    1990-09-01

    The results of tests for leakage performed on ten IR sensor dewars are presented, and the design principles of the new testing devices are discussed. The ultrasensitive leak detector used for testing is compared to conventional detectors. The superfine leak calibrator consisting of a tracer gas supply, an aliquot volume, a pressure transducer, temperature gage, and valves was used to measure leak rates in the E-4 to E-12 std cc He/s range. The testing method is explained, including the gases used, the quadrupole mass analyzer, the reference leak calibration, and the temperature coefficient of the reference leak. The test results of the IR sensor dewars are shown: seven showed leak rates in the E-15 std cc He/s range, two had no detectable leaks, and one had a mid-range E-14 leak. The shelf lives of the dewars are calculated based on the results. The vacuum integrity of small IR sensor dewars can be reliably tested to the range of 1E-15 std cc He/s using the ultrasensitive leak detector and the superfine leak calibrator.

  3. Engineering study of tank leaks related to hydraulic retrieval of sludge from tank 241-C-106. Revision 1

    SciTech Connect

    Lowe, S.S.; Carlos, W.C.; Irwin, J.J.; Khaleel, R.; Kline, N.W.; Ludowise, J.D.; Marusich, R.M.; Rittman, P.D.

    1993-06-09

    This study evaluates hydraulic retrieval (sluicing) of the waste in single-shell tank 241-C-106 with respect to the likelihood of tank leaks, gross volumes of potential leaks, and their consequences. A description of hydraulic retrieval is developed to establish a baseline for the study. Leak models are developed based on postulated leak mechanisms to estimate the amount of waste that could potentially leak while sluicing. Transport models describe the movement of the waste constituents in the surrounding soil and groundwater after a leak occurs. Environmental impact and risk associated with tank leaks are evaluated. Transport of leaked material to the groundwater is found to be dependent on the rate of recharge of moisture in the soil for moderate-sized leaks. Providing a cover over the tank and surrounding area would eliminate the recharge. The bulk of any leaked material would remain in the vicinity of the tank for remedial action.

  4. Factors affecting the location and shape of face seal leak sites on half-mask respirators.

    PubMed

    Oestenstad, Riedar Kent; Bartolucci, Alfred A

    2010-06-01

    While there have been a number of studies on the effect of leak site and shape on the magnitude of measured leakage through respirator face seals, there have been very few studies to identify the location and size of these leaks. In a previous study we used a method of identifying the location and shape of respirator leaks on a half-mask respirator by the deposition of a fluorescent tracer during a fit test, and testing for their association with facial dimensions. The purpose of this study was to apply that methodology to conduct multiple fit tests to determine if gender, respirator brand, repeated fit tests, and test exercises affected the location and shape of face seal leak sites. Categorical analysis found that none of these factors had a significant effect on the location and shape of leaks. General linear model analysis found some significant effects of the study factors on leaks, but facial dimensions had a greater effect, and there were significant differences between facial dimensions of subjects with a leak and those without. Significant differences in leak site distributions between this and the previous study may have been due to differences in facial dimensions and racial/ethnic composition. Twice as many diffuse leaks as point leaks were observed in both studies, indicating that slit-like leaks would be most appropriate on mannequins used in laboratory respirator leakage studies, and in respirator flow and penetration models. That the study factors had no significant effects in the categorical analysis, significant effects for facial dimensions were found in the linear analysis, and leak site distribution differences between this and our previous study may have been affected by differences in facial dimensions, indicate that, in addition to size, the shape of an individual's face may be an important determinant of leak sites on a half-mask respirator. This would have implications for the design of respirator facepieces and in the selection of

  5. 82. Photocopied August 1978. PREPARATIONS FOR REPAIRING A FOREBAY LEAK ...

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

    82. Photocopied August 1978. PREPARATIONS FOR REPAIRING A FOREBAY LEAK IN 1907, VIEW FROM FOREBAY. THE SILLS OF THE FOREBAY APRON WHICH HAD CRACKED AND SAGGED ARE CLEARLY VISIBLE IN THE CENTER OF THE PHOTOGRAPH. NOTE ALSO THE PENSTOCK GATE SECTION AND THE TRAVELLING GATE HOIST ABOVE THE DAMAGED AREA. THIS WAS THE MEANS USED FOR SHUTTING OFF INDIVIDUAL PENSTOCKS PRIOR TO C. 1920. THREE OF THE SECTIONS (WOODEN) SHOWN WERE REQUIRED TO CLOSE OFF A PENSTOCK. THE TRAVELLING HOIST WAS MANUALLY OPERATED. (511) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

  6. Single-shell tank leak emergency pumping guide. Revision 5

    SciTech Connect

    Wiggins, D.D.

    1994-10-04

    This document provides general information on all Single-Shell Tank Farms about readiness and special concerns for Emergency Pumping and identifies the required actions when a Single-Shell tank is identified as a leaking tank. Tank Transfer Routes are described, possible heat trace circuits are outlined, and tank riser status and obstructions are documented. Locations of existing saltwell systems and spares, information on emergency pumping equipment, watch list tank status, and transfer line integrity assessments are all included. A matrix of required actions to emergency pump individual tanks, and lists of useful drawings, procedures, work procedure outlines, and references are also provided.

  7. Sodium Leak Channels in Neuronal Excitability and Rhythmic Behaviors

    PubMed Central

    Ren, Dejian

    2011-01-01

    Extracellular K+, Na+, and Ca2+ ions all influence the resting membrane potential of the neuron. However, the mechanisms by which extracellular Na+ and Ca2+ regulate basal neuronal excitability are not well understood. Recent findings suggest that NALCN, in association with UNC79 and UNC80, contributes a basal Na+ leak conductance in neurons. Mutations in Nalcn, Unc79, or Unc80 lead to severe phenotypes that include neonatal lethality and disruption in rhythmic behaviors. This review discusses the properties of the NALCN complex, its regulation, and its contribution to neuronal function and animal behavior. PMID:22196327

  8. Carbon granule probe microphone for leak detection. [recovery boilers

    NASA Technical Reports Server (NTRS)

    Parthasarathy, S. P. (Inventor)

    1985-01-01

    A microphone which is not subject to corrosion is provided by employing carbon granules to sense sound waves. The granules are packed into a ceramic tube and no diaphragm is used. A pair of electrodes is located in the tube adjacent the carbon granules and are coupled to a sensing circuit. Sound waves cause pressure changes on the carbon granules which results in a change in resistance in the electrical path between the electrodes. This change in resistance is detected by the sensing circuit. The microphone is suitable for use as a leak detection probe in recovery boilers, where it provides reliable operation without corrosion problems associated with conventional microphones.

  9. What was leaking from a hazardous-waste dump

    SciTech Connect

    Hites, R.A.

    1988-05-15

    The city of Niagara Falls, N.Y., is the home of several toxic waste disposal sites, the most famous of which is Love Canal. Although less well known, the Hyde Park dump is equally noxious. This hazardous-waste dump was operated by the Hooker Chemical Company from about 1953 to 1975. Approximately 55,000 tons of halogenated waste were buried at this site, which is just north of the city. The Hyde Park dump is drained by Bloody Run Creek. Ronald A. Hites of Indiana University outlines the steps taken to identify the structures of organic compounds leaking from the Hyde Park dump.

  10. Portable Rapid Test Fuel Tank Leak Detection System

    DTIC Science & Technology

    2010-04-01

    aspects of the bulk tank leak detection method . It is not intended to provide a thorough description of the principles behind the system or how the...no Does the Method detect the presence of water in the bottom of the tank? ( ) yes (X) no B-2 Principle of Operation What technique...rates of 0.10 gal/hr and 0.20 gal/hr with a very high PD and very low PFA. This provides a significant improvement over current methods technologically

  11. Fiber-Optic Based Compact Gas Leak Detection System

    NASA Technical Reports Server (NTRS)

    deGroot, Wim A.

    1995-01-01

    A propellant leak detection system based on Raman scattering principles is introduced. The proposed system is flexible and versatile as the result of the use of optical fibers. It is shown that multiple species can be monitored simultaneously. In this paper oxygen, nitrogen, carbon monoxide, and hydrogen are detected and monitored. The current detection sensitivity for both hydrogen and carbon monoxide is 1% partial pressure at ambient conditions. The sensitivity for oxygen and nitrogen is 0.5% partial pressure. The response time to changes in species concentration is three minutes. This system can be used to monitor multiple species at several locations.

  12. Leak protection system on a tank for storing or transporting liquefied gas

    SciTech Connect

    Kvamsdal, R.

    1981-01-20

    An improved leak-protection system for spherical cargo tanks carrying LNG eliminates the drainage pumps and the protective insulation on the inner bottom of the ship below the tank, as found in current leak-protection designs. The new design incorporates a catch basin beneath the tank to hold any leaked cargo. The basin is large enough to allow the LNG to gradually evaporate. With this arrangement, the pump system is limited to units for draining water that has leaked in. Designed with two multicelled levels, the catch basin distributes the leaked fluid over the largest possible area, regardless of the trim or list of the moving ship. The aluminum structure of the basin prevents any thermal shock from affecting the hull of the ship below the leaking tank.

  13. Assessment of volume and leak measurements during CPAP using a neonatal lung model.

    PubMed

    Fischer, H S; Roehr, C C; Proquitté, H; Wauer, R R; Schmalisch, G

    2008-01-01

    Although several commercial devices are available which allow tidal volume and air leak monitoring during continuous positive airway pressure (CPAP) in neonates, little is known about their measurement accuracy and about the influence of air leaks on volume measurement. The aim of this in vitro study was the validation of volume and leak measurement under CPAP using a commercial ventilatory device, taking into consideration the clinical conditions in neonatology. The measurement accuracy of the Leoni ventilator (Heinen & Löwenstein, Germany) was investigated both in a leak-free system and with leaks simulated using calibration syringes (2-10 ml, 20-100 ml) and a mechanical lung model. Open tubes of variable lengths were connected for leak simulation. Leak flow was measured with the flow-through technique. In a leak-free system the mean relative volume error +/-SD was 3.5 +/- 2.6% (2-10 ml) and 5.9 +/- 0.7% (20-60 ml), respectively. The influence of CPAP level, driving flow, respiratory rate and humidification of the breathing gas on the volume error was negligible. However, an increasing F(i)O(2) caused the measured tidal volume to increase by up to 25% (F(i)O(2) = 1.0). The relative error +/- SD of the leak measurements was -0.2 +/- 11.9%. For leaks > 19%, measured tidal volume was underestimated by more than 10%. In conclusion, the present in vitro study showed that the Leoni allowed accurate volume monitoring under CPAP conditions similar to neonates. Air leaks of up to 90% of patient flow were reliably detected. For an F(i)O(2) > 0.4 and for leaks > 19%, a numerical correction of the displayed volume should be performed.

  14. Hanford Single-Shell Tank Leak Causes and Locations - 241-A Farm

    SciTech Connect

    Girardot, Crystal L.; Harlow, Donald G.

    2013-09-10

    This document identifies 241-A Tank Farm (A Farm) leak causes and locations for the 100 series leaking tanks (241-A-104 and 241-A-105) identified in RPP-ENV-37956, Hanford A and AX Farm Leak Assessment Report. This document satisfies the A Farm portion of the target (T04) in the Hanford Federal Facility Agreement and Consent Order milestone M-045-91F.

  15. Hanford Single-Shell Tank Leak Causes and Locations - 241-T Farm

    SciTech Connect

    Girardot, Crystal L.; Harlow, Donald G.

    2014-05-15

    This document identifies 241-T Tank Farm (T Farm) leak causes and locations for the 100 series leaking tanks (241-T-106 and 241-T-111) identified in RPP-RPT-55084, Rev. 0, Hanford 241-T Farm Leak Inventory Assessment Report. This document satisfies the T Farm portion of the target (T04) in the Hanford Federal Facility Agreement and Consent Order milestone M-045-91F.

  16. Hanford Single-Shell Tank Leak Causes and Locations - 241-C Farm

    SciTech Connect

    Girardot, Crystal L.; Harlow, Donald G.

    2013-07-30

    This document identifies 241-C Tank Farm (C Farm) leak causes and locations for the 100 series leaking tanks (241-C-101 and 241-C-105) identified in RPP-RPT-33418, Rev. 2, Hanford C-Farm Leak Inventory Assessments Report. This document satisfies the C Farm portion of the target (T04) in the Hanford Federal Facility Agreement and Consent Order milestone M-045-91F.

  17. Hanford Single-Shell Tank Leak Causes and Locations - 241-U Farm

    SciTech Connect

    Girardot, Crystal L.; Harlow, Donald G.

    2013-12-02

    This document identifies 241-U Tank Farm (U Farm) leak causes and locations for the 100 series leaking tanks (241-U-104, 241-U-110, and 241-U-112) identified in RPP-RPT-50097, Rev. 0, Hanford 241-U Farm Leak Inventory Assessment Report. This document satisfies the U-Farm portion of the target (T04) in the Hanford Federal Facility Agreement and Consent Order milestone M-045-91F.

  18. Hanford Single Shell Tank Leak Causes and Locations - 241-TX Farm

    SciTech Connect

    Girardot, C. L.; Harlow, D> G.

    2014-07-22

    This document identifies 241-TX Tank Farm (TX Farm) leak causes and locations for the 100 series leaking tanks (241-TX-107 and 241-TX-114) identified in RPP-RPT-50870, Rev. 0, Hanford 241-TX Farm Leak Inventory Assessment Report. This document satisfies the TX Farm portion of the target (T04) in the Hanford Federal Facility Agreement and Consent Order milestone M-045-91F.

  19. Ultra high vacuum pumping system and high sensitivity helium leak detector

    DOEpatents

    Myneni, G.R.

    1997-12-30

    An improved helium leak detection method and apparatus are disclosed which increase the leak detection sensitivity to 10{sup {minus}13} atm cc/s. The leak detection sensitivity is improved over conventional leak detectors by completely eliminating the use of o-rings, equipping the system with oil-free pumping systems, and by introducing measured flows of nitrogen at the entrances of both the turbo pump and backing pump to keep the system free of helium background. The addition of dry nitrogen flows to the system reduces back streaming of atmospheric helium through the pumping system as a result of the limited compression ratios of the pumps for helium. 2 figs.

  20. Ultra high vacuum pumping system and high sensitivity helium leak detector

    DOEpatents

    Myneni, Ganapati Rao

    1997-01-01

    An improved helium leak detection method and apparatus are disclosed which increase the leak detection sensitivity to 10.sup.-13 atm cc s.sup.-1. The leak detection sensitivity is improved over conventional leak detectors by completely eliminating the use of o-rings, equipping the system with oil-free pumping systems, and by introducing measured flows of nitrogen at the entrances of both the turbo pump and backing pump to keep the system free of helium background. The addition of dry nitrogen flows to the system reduces backstreaming of atmospheric helium through the pumping system as a result of the limited compression ratios of the pumps for helium.

  1. Method of locating a leaking fuel element in a fast breeder power reactor

    DOEpatents

    Honekamp, John R.; Fryer, Richard M.

    1978-01-01

    Leaking fuel elements in a fast reactor are identified by measuring the ratio of .sup.134 Xe to .sup.133 Xe in the reactor cover gas following detection of a fuel element leak, this ratio being indicative of the power and burnup of the failed fuel element. This procedure can be used to identify leaking fuel elements in a power breeder reactor while continuing operation of the reactor since the ratio measured is that of the gases stored in the plenum of the failed fuel element. Thus, use of a cleanup system for the cover gas makes it possible to identify sequentially a multiplicity of leaking fuel elements without shutting the reactor down.

  2. 40 CFR 60.483-1 - Alternative standards for valves-allowable percentage of valves leaking.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Standards of Performance for Equipment Leaks of VOC in the Synthetic Organic Chemicals Manufacturing Industry for which Construction, Reconstruction, or Modification Commenced After January 5, 1981, and on...

  3. 40 CFR 60.483-1 - Alternative standards for valves-allowable percentage of valves leaking.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Standards of Performance for Equipment Leaks of VOC in the Synthetic Organic Chemicals Manufacturing Industry for which Construction, Reconstruction, or Modification Commenced After January 5, 1981, and on...

  4. Hanford Single-Shell Tank Leak Causes and Locations - 241-BY and 241-TY Farm

    SciTech Connect

    Girardot, Crystal L.; Harlow, Donald G.

    2013-11-19

    This document identifies 241-BY Tank Farm (BY Farm) and 241-TY Tank Farm (TY Farm) leak causes and locations for the 100 series leaking tanks (241-BY-103, 241-TY-103, 241-TY-104, 241-TY-105, and 241-TY-106) identified in RPP-RPT-43704, Hanford BY Farm Leak Assessments Report, and in RPP-RPT-42296, Hanford TY Farm Leak Assessments Report. This document satisfies the BY and TY Farm portion of the target (T04) in Hanford Federal Facility Agreement and Consent Order milestone M-045-91F.

  5. Sellar Reconstruction and Rates of Delayed Cerebrospinal Fluid Leak after Endoscopic Pituitary Surgery

    PubMed Central

    Sanders-Taylor, Chris; Anaizi, Amjad; Kosty, Jennifer; Zimmer, Lee A.; Theodosopoulos, Phillip V.

    2015-01-01

    Objectives Delayed cerebrospinal fluid (CSF) leaks are a complication in transsphenoidal surgery, potentially causing morbidity and longer hospital stays. Sella reconstruction can limit this complication, but is it necessary in all patients? Design Retrospective review. Setting Single-surgeon team (2005–2012) addresses this trend toward graded reconstruction. Participants A total of 264 consecutive patients with pituitary adenomas underwent endoscopic transsphenoidal resections. Sellar defects sizable to accommodate a fat graft were reconstructed. Main outcomes Delayed CSF leak and autograft harvesting. Results Overall, 235 (89%) had reconstruction with autograft (abdominal fat, septal bone/cartilage) and biological glue. Delayed CSF leak was 1.9%: 1.7%, and 3.4% for reconstructed and nonreconstructed sellar defects, respectively (p = 0.44). Complications included one reoperation for leak, two developed meningitis, and autograft harvesting resulted in abdominal hematoma in 0.9% and wound infection in 0.4%. Conclusion In our patients, delayed CSF leaks likely resulted from missed intraoperative CSF leaks or postoperative changes. Universal sellar reconstruction can preemptively treat missed leaks and provide a barrier for postoperative changes. When delayed CSF leaks occurred, sellar reconstruction often allowed for conservative treatment (i.e., lumbar drain) without repeat surgery. We found universal reconstruction provides a low risk of delayed CSF leak with minimal complications. PMID:26225317

  6. Digital radar-gram processing for water pipelines leak detection

    NASA Astrophysics Data System (ADS)

    García-Márquez, Jorge; Flores, Ricardo; Valdivia, Ricardo; Carreón, Dora; Malacara, Zacarías; Camposeco, Arturo

    2006-02-01

    Ground penetrating radars (GPR) are useful underground exploration devices. Applications are found in archaeology, mine detection, pavement evaluation, among others. Here we use a GPR to detect by an indirect way, the anomalies caused by the presence of water in the neighborhood of an underground water pipeline. By Fourier transforming a GPR profile map we interpret the signal as spatial frequencies, instead of the temporal frequencies, that composes the profile map. This allows differentiating between signals returning from a standard subsoil feature from those coming back from anomalous zones. Facilities in Mexican cities are commonly buried up to 2.5 m. Their constituent materials are PVC, concrete or metal, typically steel. GPRs are ultra-wide band devices; leak detection must be an indirect process since echoes due to the presence of underground zones with high moisture levels are masked by dense reflections (clutter). In radargrams the presence of water is visualized as anomalies in the neighborhood of the facility. Enhancement of these anomalies will give us the information required to detect leaks.

  7. Chauncey Leake and the development of bioethics in America.

    PubMed

    Brody, Howard

    2014-03-01

    Chauncey D. Leake (1896-1978) occupies a unique place in the history of American bioethics. A pharmacologist, he was largely an autodidact in both history and philosophy, and believed that ethics should ideally be taught to medical students by those with philosophical training. After pioneering work on medical ethics during the 1920s, he helped to lay the groundwork for important centers for bioethics and medical humanities at two institutions where he worked, the University of California-San Francisco and the University of Texas Medical Branch-Galveston. Understanding Leake's role in American bioethics requires navigating a number of paradoxes--why he was described respectfully in his time but largely forgotten today; how in the 1920s he could write forward-looking pieces that anticipated many of the themes taken up by bioethics a half-century later, yet played largely a reactionary role when the new bioethics actually arrived; and why he advocated turning to philosophy and philosophers for a proper understanding of ethics, yet appeared often to misunderstand philosophical ethics.

  8. Non-linear leak currents affect mammalian neuron physiology

    PubMed Central

    Huang, Shiwei; Hong, Sungho; De Schutter, Erik

    2015-01-01

    In their seminal works on squid giant axons, Hodgkin, and Huxley approximated the membrane leak current as Ohmic, i.e., linear, since in their preparation, sub-threshold current rectification due to the influence of ionic concentration is negligible. Most studies on mammalian neurons have made the same, largely untested, assumption. Here we show that the membrane time constant and input resistance of mammalian neurons (when other major voltage-sensitive and ligand-gated ionic currents are discounted) varies non-linearly with membrane voltage, following the prediction of a Goldman-Hodgkin-Katz-based passive membrane model. The model predicts that under such conditions, the time constant/input resistance-voltage relationship will linearize if the concentration differences across the cell membrane are reduced. These properties were observed in patch-clamp recordings of cerebellar Purkinje neurons (in the presence of pharmacological blockers of other background ionic currents) and were more prominent in the sub-threshold region of the membrane potential. Model simulations showed that the non-linear leak affects voltage-clamp recordings and reduces temporal summation of excitatory synaptic input. Together, our results demonstrate the importance of trans-membrane ionic concentration in defining the functional properties of the passive membrane in mammalian neurons as well as other excitable cells. PMID:26594148

  9. Using Decision Trees to Detect and Isolate Simulated Leaks in the J-2X Rocket Engine

    NASA Technical Reports Server (NTRS)

    Schwabacher, Mark A.; Aguilar, Robert; Figueroa, Fernando F.

    2009-01-01

    The goal of this work was to use data-driven methods to automatically detect and isolate faults in the J-2X rocket engine. It was decided to use decision trees, since they tend to be easier to interpret than other data-driven methods. The decision tree algorithm automatically "learns" a decision tree by performing a search through the space of possible decision trees to find one that fits the training data. The particular decision tree algorithm used is known as C4.5. Simulated J-2X data from a high-fidelity simulator developed at Pratt & Whitney Rocketdyne and known as the Detailed Real-Time Model (DRTM) was used to "train" and test the decision tree. Fifty-six DRTM simulations were performed for this purpose, with different leak sizes, different leak locations, and different times of leak onset. To make the simulations as realistic as possible, they included simulated sensor noise, and included a gradual degradation in both fuel and oxidizer turbine efficiency. A decision tree was trained using 11 of these simulations, and tested using the remaining 45 simulations. In the training phase, the C4.5 algorithm was provided with labeled examples of data from nominal operation and data including leaks in each leak location. From the data, it "learned" a decision tree that can classify unseen data as having no leak or having a leak in one of the five leak locations. In the test phase, the decision tree produced very low false alarm rates and low missed detection rates on the unseen data. It had very good fault isolation rates for three of the five simulated leak locations, but it tended to confuse the remaining two locations, perhaps because a large leak at one of these two locations can look very similar to a small leak at the other location.

  10. Air pollutant penetration through airflow leaks into buildings

    SciTech Connect

    Liu, De-Ling

    2002-01-01

    The penetration of ambient air pollutants into the indoor environment is of concern owing to several factors: (1) epidemiological studies have shown a strong association between ambient fine particulate pollution and elevated risk of human mortality; (2) people spend most of their time in indoor environments; and (3) most information about air pollutant concentration is only available from ambient routine monitoring networks. A good understanding of ambient air pollutant transport from source to receptor requires knowledge about pollutant penetration across building envelopes. Therefore, it is essential to gain insight into particle penetration in infiltrating air and the factors that affect it in order to assess human exposure more accurately, and to further prevent adverse human health effects from ambient particulate pollution. In this dissertation, the understanding of air pollutant infiltration across leaks in the building envelope was advanced by performing modeling predictions as well as experimental investigations. The modeling analyses quantified the extent of airborne particle and reactive gas (e.g., ozone) penetration through building cracks and wall cavities using engineering analysis that incorporates existing information on building leakage characteristics, knowledge of pollutant transport processes, as well as pollutant-surface interactions. Particle penetration is primarily governed by particle diameter and by the smallest dimension of the building cracks. Particles of 0.1-1 μm are predicted to have the highest penetration efficiency, nearly unity for crack heights of 0.25 mm or higher, assuming a pressure differential of 4 Pa or greater and a flow path length of 3 cm or less. Supermicron and ultrafine particles (less than 0.1 μm) are readily deposited on crack surfaces by means of gravitational settling and Brownian diffusion, respectively. The fraction of ozone penetration through building leaks could vary widely, depending significantly on its

  11. Fuel leak detection apparatus for gas cooled nuclear reactors

    DOEpatents

    Burnette, Richard D.

    1977-01-01

    Apparatus is disclosed for detecting nuclear fuel leaks within nuclear power system reactors, such as high temperature gas cooled reactors. The apparatus includes a probe assembly that is inserted into the high temperature reactor coolant gaseous stream. The probe has an aperture adapted to communicate gaseous fluid between its inside and outside surfaces and also contains an inner tube for sampling gaseous fluid present near the aperture. A high pressure supply of noncontaminated gas is provided to selectively balance the pressure of the stream being sampled to prevent gas from entering the probe through the aperture. The apparatus includes valves that are operable to cause various directional flows and pressures, which valves are located outside of the reactor walls to permit maintenance work and the like to be performed without shutting down the reactor.

  12. Narrative Review: Clarkson Disease-Systemic Capillary Leak Syndrome

    PubMed Central

    Druey, Kirk M.; Greipp, Philip R.

    2010-01-01

    In 1960, Dr. Bayard Clarkson described a patient experiencing sporadic episodes of hypovolemia, hypotension, and edema. Plasma during the acute attack induced a “shock”-like syndrome when given systemically in rats. The unusual and enigmatic “Systemic Capillary Leak Syndrome” (SCLS) named for Dr. Clarkson is of unknown etiology and is characterized by transient, severe, reversible hemoconcentration and hypoalbuminemia due to leakage of fluids and macromolecules (up to 900 kDa) into tissues (1). Fewer than 150 cases of SCLS have been reported since 1960, but the nonspecific presenting symptoms and signs and high mortality rate may have resulted in under-recognition of this disorder. Given the substantial overlap of SCLS with other “shock” syndromes, including sepsis, anaphylaxis, and angioedema, clinicians should consider this diagnosis in patients with unexplained edema, increased hematocrit, and hypotension. PMID:20643990

  13. Transcatheter closure of paravalvular leaks: state of the art.

    PubMed

    Cruz-Gonzalez, I; Rama-Merchan, J C; Rodríguez-Collado, J; Martín-Moreiras, J; Diego-Nieto, A; Barreiro-Pérez, M; Sánchez, P L

    2017-02-01

    Paravalvular leak (PVL) is a serious complication after surgical valve replacement or after transcatheter aortic valve replacement. Approximately 1-5% of PVLs can lead to serious clinical consequences, including congestive heart failure and/or haemolytic anaemia. For years, surgical re-intervention has been considered the treatment of choice for symptomatic patients with PVLs. However, surgical re-intervention is associated with a high risk of morbidity and mortality. Transcatheter PVL (TPVL) closure is a less invasive alternative to surgical re-intervention. The safety and feasibility of TPVL closure has been confirmed in several registries and a meta-analysis.In this review, we discuss the clinical implications and diagnosis of PVLs, technical considerations for TPVL, execution of the procedure and assessment of the results.

  14. The Use of Spontaneous Raman Scattering for Hydrogen Leak Detection

    NASA Technical Reports Server (NTRS)

    Degroot, Wim A.

    1994-01-01

    A fiber optic probe has been built and demonstrated that utilizes back scattered spontaneous Raman spectroscopy to detect and identify gaseous species. The small probe, coupled to the laser and data acquisition equipment with optical fibers, has applications in gaseous leak detection and process monitoring. The probe design and data acquisition system are described. Raman scattering theory has been reviewed and the results of intensity calculations of hydrogen and nitrogen Raman scattering are given. Because the device is in its developmental stage, only preliminary experimental results are presented here. Intensity scans across the rotational-vibrational Raman lines of nitrogen and hydrogen are presented. Nitrogen at a partial pressure of 0.077 MPa was detected. Hydrogen at a partial pressure of 2 kPa approached the lower limit of detectability with the present apparatus. Potential instrument improvements that would allow more sensitive and rapid hydrogen detection are identified.

  15. Internal dissipation and heat leaks in quantum thermodynamic cycles.

    PubMed

    Correa, Luis A; Palao, José P; Alonso, Daniel

    2015-09-01

    The direction of the steady-state heat currents across a generic quantum system connected to multiple baths may be engineered to realize virtually any thermodynamic cycle. In spite of their versatility, such continuous energy-conversion systems are generally unable to operate at maximum efficiency due to non-negligible sources of irreversible entropy production. In this paper we introduce a minimal model of irreversible absorption chiller. We identify and characterize the different mechanisms responsible for its irreversibility, namely heat leaks and internal dissipation, and gauge their relative impact in the overall cooling performance. We also propose reservoir engineering techniques to minimize these detrimental effects. Finally, by looking into a known three-qubit embodiment of the absorption cooling cycle, we illustrate how our simple model may help to pinpoint the different sources of irreversibility naturally arising in more complex practical heat devices.

  16. Method for fabricating a mass spectrometer inlet leak

    NASA Technical Reports Server (NTRS)

    Harris, R. F. (Inventor)

    1977-01-01

    A method of fabricating an inlet leak for measuring chemically reactive gases is proposed. The method involves the steps of preparing a selected internal surface of a high melting point metal tubing for sealing to a glass tubing. A portion of the glass tubing is inserted into the prepared portion of the metal tubing, the glass tubing having an outer diameter substantially the same as the inner diameter of the metal tubing. The inserted glass tubing is sealed to the internal surface of the metal tubing; the glass tubing is drawn under a magnifying device to reduce the entire interior diameter thereof to substantially two microns; and an end portion of the drawing glass tubing is broken away.

  17. Volumetric leak detection in large underground storage tanks. Volume 1

    SciTech Connect

    Starr, J.W.; Wise, R.F.; Maresca, J.W.

    1991-08-01

    A set of experiments was conducted to determine whether volumetric leak detection system presently used to test underground storage tanks (USTs) up to 38,000 L (10,000 gal) in capacity could meet EPA's regulatory standards for tank tightness and automatic tank gauging systems when used to test tanks up to 190,000 L (50,000 gal) in capacity. The experiments, conducted on two partially filled 190,000-L (50,000-gal) USTs at Griffiss Air Force Base in upstate New York during late August 1990, showed that a system's performance in large tanks depends primarily on the accuracy of the temperature compensation, which is inversely proportional to the volume of product in the tank. Errors in temperature compensation that were negligible in tests in small tanks were important in large tanks. The experiments further suggest that a multiple-test strategy is also required.

  18. Aortic Angiosarcoma: A Rare Cause for Leaking Thoracic Aneurysm

    SciTech Connect

    Hales, S. L. Locke, R.; Sandison, A.; Jenkins, M.; Hamady, M.

    2011-02-15

    Primary malignant tumours of the aorta are rare. They present with aneurysm formation, arterial occlusion, and embolic phenomenon. We report the case of a 56-year-old man whose initial presentation and investigations lead to emergency endovascular stenting of a descending thoracic aneurysm with a contained leak. Initial response was favourable, yet the patient presented again with worsening symptoms. The circum-aortic haematoma expanded by 50% on subsequent imaging, but no endoleak was identified. When altered bone marrow signal was identified on magnetic resonance imaging, the possibility of malignancy was considered. A metastatic skin lesion was then biopsied, which demonstrated morphological and immunohistochemical features consistent with metastases from a pleomorphic sarcoma of the aorta.

  19. Portable remote laser sensor for methane leak detection

    NASA Technical Reports Server (NTRS)

    Grant, W. B.; Hinkley, E. D., Jr. (Inventor)

    1984-01-01

    A portable laser system for remote detection of methane gas leaks and concentrations is disclosed. The system transmitter includes first and second lasers, tuned respectively to a wavelength coincident with a strong absorption line of methane and a reference wavelength which is weakly absorbed by methane gas. The system receiver includes a spherical mirror for collecting the reflected laser radiation and focusing the collected radiation through a narrowband optical filter onto an optial detector. The filter is tuned to the wavelength of the two lasers, and rejects background noise. The output of the optical detector is processed by a lock-in detector synchronized to the chopper, and which measures the difference between the first wavelength signal and the reference wavelength signal.

  20. Leak rate analysis of the Westinghouse Reactor Coolant Pump

    SciTech Connect

    Boardman, T.; Jeanmougin, N.; Lofaro, R.; Prevost, J.

    1985-07-01

    An independent analysis was performed by ETEC to determine what the seal leakage rates would be for the Westinghouse Reactor Coolant Pump (RCP) during a postulated station blackout resulting from loss of ac electric power. The object of the study was to determine leakage rates for the following conditions: Case 1: All three seals function. Case 2: No. 1 seal fails open while Nos. 2 and 3 seals function. Case 3: All three seals fail open. The ETEC analysis confirmed Westinghouse calculations on RCP seal performance for the conditions investigated. The leak rates predicted by ETEC were slightly lower than those predicted by Westinghouse for each of the three cases as summarized below. Case 1: ETEC predicted 19.6 gpm, Westinghouse predicted 21.1 gpm. Case 2: ETEC predicted 64.7 gpm, Westinghouse predicted 75.6 gpm. Case 3: ETEC predicted 422 gpm, Westinghouse predicted 480 gpm. 3 refs., 22 figs., 6 tabs.

  1. Idiopathic Systemic Capillary Leak Syndrome: A Case Report

    PubMed Central

    Yardimci, Bulent; Kazancioglu, Rumeyza

    2016-01-01

    Introduction Idiopathic systemic capillary leak syndrome (ISCLS) is rarely seen, and presents with recurrent episodes of hypotension, shock, hemoconcentration, and hypoproteinemia. The main pathology is the dysfunction of the vascular endothelium, and it is characterized by an increase of capillary permeability that is accompanied by the loss of intravascular fluid and protein. Case Presentation We present a 58-year-old female who presented with peripheral edema, leg pain, and syncope at the emergency department. Interestingly demyemilising neuropathy, which is a rare finding, ensued on day 4. She is still being treated using intravenous immunoglobulin therapy. Conclusions The early signs and symptoms of ISCLS may be subtle; therefore the diagnosis can easily be missed and prompt treatment of the syndrome may be postponed. Thus, the clinician must consider ISCLS in differential diagnosis in cases of hypotension, hemoconcentration, and hypoalbuminemia. PMID:27195144

  2. Analysis of electric and magnetic fields leaking from induction heaters.

    PubMed

    Andreuccetti, D; Bini, M; Ignesti, A; Olmi, R; Rubino, N; Vanni, R

    1988-01-01

    Results are presented of an investigation on electric and magnetic fields leaking from inductive (magnetic) heaters that are used for thermal processing of high-power electron tubes and lasers in an industrial plant. Measurements of electric and magnetic fields were done using both commercially available and laboratory-developed instrumentation. Isotropic H-field sensors were developed to allow quantitative evaluation of high-intensity magnetic fields. Ten induction heaters with nominal A.C. power ranging from 2.5 kW to 15 kW and operating at frequencies between 300 kHz and 790 kHz were surveyed. Electric field strengths up to 8 kV/m and magnetic field strengths up to 20 A/m were measured.

  3. The effects of air leaks on solar air heating systems

    NASA Technical Reports Server (NTRS)

    Elkin, R.; Cash, M.

    1979-01-01

    This paper presents the results of an investigation to determine the effects of leakages in collector and duct work on the system performance of a typical single-family residence solar air heating system. Positive (leakage out) and negative (leakage in) pressure systems were examined. Collector and duct leakage rates were varied from 10 to 30 percent of the system flow rate. Within the range of leakage rates investigated, solar contribution to heated space and domestic hot water loads was found to be reduced up to 30 percent from the no-leak system contribution with duct leakage equally divided between supply and return duct; with supply duct leakage greater than return leakage a reduction of up to 35 percent was noted. The negative pressure system exhibited a reduction in solar contribution somewhat larger than the positive pressure system for the same leakage rates.

  4. Internal dissipation and heat leaks in quantum thermodynamic cycles

    NASA Astrophysics Data System (ADS)

    Correa, Luis A.; Palao, José P.; Alonso, Daniel

    2015-09-01

    The direction of the steady-state heat currents across a generic quantum system connected to multiple baths may be engineered to realize virtually any thermodynamic cycle. In spite of their versatility, such continuous energy-conversion systems are generally unable to operate at maximum efficiency due to non-negligible sources of irreversible entropy production. In this paper we introduce a minimal model of irreversible absorption chiller. We identify and characterize the different mechanisms responsible for its irreversibility, namely heat leaks and internal dissipation, and gauge their relative impact in the overall cooling performance. We also propose reservoir engineering techniques to minimize these detrimental effects. Finally, by looking into a known three-qubit embodiment of the absorption cooling cycle, we illustrate how our simple model may help to pinpoint the different sources of irreversibility naturally arising in more complex practical heat devices.

  5. A HYBRID THERMAL VIDEO AND FTTR SPECTROMETER FOR RAPIDLY LOCATING AND CHARACTERIZING GAS LEAKS

    EPA Science Inventory

    Undiscovered gas leaks, known as fugitive emissions, in chemical plants and refinery operations can impact regional air quality as well as being a public health problem. Surveying a facility for potential gas leaks can be a daunting task. An efficient, accurate and cost-effecti...

  6. EPA and Partners Host 5K for Fix a Leak Week

    EPA Pesticide Factsheets

    DALLAS - (March 10, 2016) The U.S. Environmental Protection Agency (EPA), the city of Fort Worth and the Fort Worth Runners Club are hosting a 5K Run/Walk to kick off the eighth annual Fix a Leak week and promote awareness to fix leaks and stop wa

  7. Sealing of large leaks in high-vacuum systems subject to mechanical and thermal stresses

    NASA Technical Reports Server (NTRS)

    Christian, J. D.; Gilbreath, W. P.

    1974-01-01

    The use of silicone rubber adhesive (particularly, G.E. RTV-108) for sealing large leaks in high vacuum systems subject to mechanical and thermal stresses is shown to be more effective than that of epoxy cements. The sealant is applied externally to the leak while the system is partially evacuated so that it is drawn into the hole.

  8. 40 CFR 63.1086 - How must I monitor for leaks to cooling water?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... system so that the cooling water flow rate is 51,031 liters per minute or less so that a leak of 3.06 kg... 40 Protection of Environment 11 2014-07-01 2014-07-01 false How must I monitor for leaks to... (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR...

  9. 40 CFR 63.1086 - How must I monitor for leaks to cooling water?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... system so that the cooling water flow rate is 51,031 liters per minute or less so that a leak of 3.06 kg... 40 Protection of Environment 11 2012-07-01 2012-07-01 false How must I monitor for leaks to... (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR...

  10. Intermediate-Scale Laboratory Experiments of Subsurface Flow and Transport Resulting from Tank Leaks

    SciTech Connect

    Oostrom, Martinus; Wietsma, Thomas W.

    2014-09-30

    Washington River Protection Solutions contracted with Pacific Northwest National Laboratory to conduct laboratory experiments and supporting numerical simulations to improve the understanding of water flow and contaminant transport in the subsurface between waste tanks and ancillary facilities at Waste Management Area C. The work scope included two separate sets of experiments: •Small flow cell experiments to investigate the occurrence of potential unstable fingering resulting from leaks and the limitations of the STOMP (Subsurface Transport Over Multiple Phases) simulator to predict flow patterns and solute transport behavior under these conditions. Unstable infiltration may, under certain conditions, create vertically elongated fingers potentially transporting contaminants rapidly through the unsaturated zone to groundwater. The types of leak that may create deeply penetrating fingers include slow release, long duration leaks in relatively permeable porous media. Such leaks may have occurred below waste tanks at the Hanford Site. •Large flow experiments to investigate the behavior of two types of tank leaks in a simple layered system mimicking the Waste Management Area C. The investigated leaks include a relatively large leak with a short duration from a tank and a long duration leak with a relatively small leakage rate from a cascade line.

  11. 10 CFR 34.27 - Leak testing and replacement of sealed sources.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Leak testing and replacement of sealed sources. 34.27... of sealed sources. (a) The replacement of any sealed source fastened to or contained in a radiographic exposure device and leak testing of any sealed source must be performed by persons authorized...

  12. 241-AN-B pit leak detection ANA-WT-LDSTA-231 acceptance test procedure

    SciTech Connect

    VANDYKE, D.W.

    1999-08-25

    This document describes the method used to test design criteria for Safety Class, Intrinsically Safe leak detector system installed in 241-AN-B Valve Pit located at 200E Tank Farms. The purpose of this Procedure is to demonstrate that the pit leak detection relay cabinet and intrinsically safe probe circuit is fully operable.

  13. SN-268 encasement leak detection ANA-WT-LDSTA-335 acceptance test procedure

    SciTech Connect

    VANDYKE, D.W.

    1999-08-25

    This document describes the method used to test design criteria for encasement leak detector system installed in 241-AN-A Encasement Line SN-268, located at 200E Tank Farms. This procedure provides instructions for demonstrating that the pit leak detection relay cabinet and intrinsically safe probe circuit is fully operable.

  14. 241-AN-A pit leak detection ANA-WT-LDSTA-331 acceptance test procedure

    SciTech Connect

    VANDYKE, D.W.

    1999-08-25

    This document describes the method used to test design criteria for Safety Class, Intrinsically Safe leak detector system installed in 241-AN-A Valve Pit located at 200E Tank Farms. The purpose of this Procedure is to demonstrate that the pit leak detection relay cabinet and intrinsically safe probe circuit is fully operable.

  15. Space Shuttle Main Engine Propellant Path Leak Detection Using Sequential Image Processing

    NASA Technical Reports Server (NTRS)

    Smith, L. Montgomery; Malone, Jo Anne; Crawford, Roger A.

    1995-01-01

    Initial research in this study using theoretical radiation transport models established that the occurrence of a leak is accompanies by a sudden but sustained change in intensity in a given region of an image. In this phase, temporal processing of video images on a frame-by-frame basis was used to detect leaks within a given field of view. The leak detection algorithm developed in this study consists of a digital highpass filter cascaded with a moving average filter. The absolute value of the resulting discrete sequence is then taken and compared to a threshold value to produce the binary leak/no leak decision at each point in the image. Alternatively, averaging over the full frame of the output image produces a single time-varying mean value estimate that is indicative of the intensity and extent of a leak. Laboratory experiments were conducted in which artificially created leaks on a simulated SSME background were produced and recorded from a visible wavelength video camera. This data was processed frame-by-frame over the time interval of interest using an image processor implementation of the leak detection algorithm. In addition, a 20 second video sequence of an actual SSME failure was analyzed using this technique. The resulting output image sequences and plots of the full frame mean value versus time verify the effectiveness of the system.

  16. 77 FR 36248 - National Uniform Emission Standards for Storage Vessel and Transfer Operations, Equipment Leaks...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-18

    ...-0871; FRL-9688-8] RIN 2060-AR00 National Uniform Emission Standards for Storage Vessel and Transfer Operations, Equipment Leaks, and Closed Vent Systems and Control Devices; and Revisions to the National... Emission Standards for Storage Vessels and Transfer Operations, Equipment Leaks, and Closed Vent...

  17. Field Demonstration of Innovative Condition Assessment Technologies for Water Mains: Leak Detection and Location

    EPA Science Inventory

    Three leak detection/location technologies were demonstrated on a 76-year-old, 2,057-ft-long portion of a cement-lined, 24-in. cast iron water main in Louisville, KY. This activity was part of a series of field demonstrations of innovative leak detection/location and condition a...

  18. 76 FR 9987 - Protection of Stratospheric Ozone: Amendments to the Section 608 Leak Repair Requirements

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-23

    ... AGENCY 40 CFR Part 82 Protection of Stratospheric Ozone: Amendments to the Section 608 Leak Repair...://epa.gov/ozone/title6/608/leak.html . SUPPLEMENTARY INFORMATION: Background The statutory and... greater than 50 pounds of ozone-depleting substances. This action proposes to streamline existing...

  19. Assessment of Field Experience Related to Pressurized Water Reactor Primary System Leaks

    SciTech Connect

    Shah, Vikram Naginbhai; Ware, Arthur Gates; Atwood, Corwin Lee; Sattison, Martin Blaine; Hartley, Robert Scott; Hsu, C.

    1999-08-01

    This paper presents our assessment of field experience related to pressurized water reactor (PWR) primary system leaks in terms of their number of rates, how aging affects frequency of leak events, the safety significance of such leaks, industry efforts to reduce leaks, and effectiveness of current leak detection systems. We have reviewed the licensee event reports to identify the events that took place during 1985 to the third quarter of 1996, and reviewed related technical literature and visited PWR plants to analyze these events. Our assessment shows that USNRC licensees have taken effective actions to reduce the number of leak events. One main reason for this decreasing trend was the elimination or reportable leakages from valve stem packing after 1991. Our review of leak events related to vibratory fatigue reveals a statistically significant decreasing trend with age (years of operation), but not in calendar time. Our assessment of worldwide data on leakage caused by thermal fatigue cracking is that the fatigue of aging piping is a safety significant issue. Our review of leak events has identified several susceptible sites in piping having high safety significance; but the inspection of some of these sites is not required by the ASME Code. These sites may be included in the risk-informed inspection programs.

  20. Assessment of Field Experience Related to Pressurized Water Reactor Primary System Leaks

    SciTech Connect

    A. G. Ware; C. Hsu; C. L. Atwood; M. B. Sattison; R. S. Hartley; V. N. Shah

    1999-02-01

    This paper presents our assessment of field experience related to pressurized water reactor (PWR) primary system leaks in terms of their number and rates, how aging affects frequency of leak events, the safety significance of such leaks, industry efforts to reduce leaks, and effectiveness of current leak detection systems. We have reviewed the licensee event reports to identify the events that took place during 1985 to the third quarter of 1996, and reviewed related technical literature and visited PWR plants to analyze these events. Our assessment shows that USNRC licensees have taken effective actions to reduce the number of leak events. One main reason for this decreasing trend was the elimination or reportable leakages from valve stem packing after 1991. Our review of leak events related to vibratory fatigue reveals a statistically significant decreasing trend with age (years of operation), but not in calendar time. Our assessment of worldwide data on leakage caused by thermal fatigue cracking is that the fatigue of aging piping is a safety significant issue. Our review of leak events has identified several susceptible sites in piping having high safety significance; but the inspection of some of these sites is not required by the ASME Code. These sites may be included in the risk-informed inspection programs.

  1. Potential role of infrared imaging for detecting facial seal leaks in filtering facepiece respirator users.

    PubMed

    Harber, Philip; Su, Jing; Badilla, Alejandro D; Rahimian, Rombod; Lansey, Kirsten R

    2015-01-01

    Infrared imaging (IRI) can detect airflow through and near respirator masks based upon temperature differences between ambient and exhaled air. This study investigated the potential usefulness of IRI for detecting leaks and providing insight into the sites and significance of leaks. Subjects (n = 165) used filtering facepiece N95 respirators (N95 FFR) in the course of a research study concerning training modalities. Short sequence video infrared images were obtained during use and with intentionally introduced facial seal leaks. Fit factor (FF) was measured with condensation nuclei count methods. IRI detected leaks were scored on a four-point scale and summarized as the Total Leak Score (TLS) over six coding regions and the presence or absence of a "Big Leak" (BL) in any location. A semi-automated interpretation algorithm was also developed. IRI detected leaks are particularly common in the nasal region, but these are of limited significance. IR imaging could effectively identify many large leaks. The TLS was related to FF. Although IRI scores were related to FF, the relationship is insufficiently close for IRI to substitute for quantitative fit-testing. Using FFRs infrared techniques have potential for identifying situations with very inadequate respiratory protection.

  2. 46 CFR 38.15-10 - Leak detection systems-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Leak detection systems-T/ALL. 38.15-10 Section 38.15-10... Requirements § 38.15-10 Leak detection systems—T/ALL. (a) A detection system shall be permanently installed to... exempt from the requirements of this paragraph. (b) The indicating instruments for the detection...

  3. Helium Mass Spectrometer Leak Detection: A Method to Quantify Total Measurement Uncertainty

    NASA Technical Reports Server (NTRS)

    Mather, Janice L.; Taylor, Shawn C.

    2015-01-01

    In applications where leak rates of components or systems are evaluated against a leak rate requirement, the uncertainty of the measured leak rate must be included in the reported result. However, in the helium mass spectrometer leak detection method, the sensitivity, or resolution, of the instrument is often the only component of the total measurement uncertainty noted when reporting results. To address this shortfall, a measurement uncertainty analysis method was developed that includes the leak detector unit's resolution, repeatability, hysteresis, and drift, along with the uncertainty associated with the calibration standard. In a step-wise process, the method identifies the bias and precision components of the calibration standard, the measurement correction factor (K-factor), and the leak detector unit. Together these individual contributions to error are combined and the total measurement uncertainty is determined using the root-sum-square method. It was found that the precision component contributes more to the total uncertainty than the bias component, but the bias component is not insignificant. For helium mass spectrometer leak rate tests where unit sensitivity alone is not enough, a thorough evaluation of the measurement uncertainty such as the one presented herein should be performed and reported along with the leak rate value.

  4. Endoscopic Transmaxillary Transposition of Temporalis Flap for Recurrent Cerebrospinal Fluid Leak Closure.

    PubMed

    Thomas, Regi; Girishan, Shabari; Chacko, Ari George

    2016-12-01

    Objective To describe the technique of endoscopic transmaxillary temporalis muscle flap transposition for the repair of a persistent postoperative sphenoidal cerebrospinal fluid leak. Design The repair of a recurrent cerebrospinal fluid leak for a patient who had undergone endoscopic transsphenoidal excision of an invasive silent corticotroph Hardy C and Knosp Grade IV pituitary adenoma was undertaken. The patient had completed postoperative radiotherapy for the residual tumor and presented with cerebrospinal fluid leak, 1 year later. The initial two attempts to repair the cerebrospinal fluid leak with free grafts failed. Therefore, an endoscopic transmaxillary transposition of the temporalis muscle flap was attempted to stop the cerebrospinal fluid leak. Results The endoscopic transmaxillary transposition of the vascularized temporalis muscle flap onto the cerebrospinal fluid leak repair site resulted in successful closure of the cerebrospinal fluid leak. Conclusion Endoscopic transmaxillary transposition of the temporalis flap resulted in closure of recurrent cerebrospinal fluid leak in a patient with recurrent pituitary adenoma, who had undergone previous surgery and radiotherapy. This technique has advantages over the endoscopic transpterygoid transposition of the same flap and could be used as a complementary technique in selected patients.

  5. Fiber optic distributed chemical sensor for the real time detection of hydrocarbon fuel leaks

    NASA Astrophysics Data System (ADS)

    Mendoza, Edgar; Kempen, C.; Esterkin, Yan; Sun, Sunjian

    2015-09-01

    With the increase worldwide demand for hydrocarbon fuels and the vast development of new fuel production and delivery infrastructure installations around the world, there is a growing need for reliable hydrocarbon fuel leak detection technologies to provide safety and reduce environmental risks. Hydrocarbon leaks (gas or liquid) pose an extreme danger and need to be detected very quickly to avoid potential disasters. Gas leaks have the greatest potential for causing damage due to the explosion risk from the dispersion of gas clouds. This paper describes progress towards the development of a fast response, high sensitivity, distributed fiber optic fuel leak detection (HySense™) system based on the use of an optical fiber that uses a hydrocarbon sensitive fluorescent coating to detect the presence of fuel leaks present in close proximity along the length of the sensor fiber. The HySense™ system operates in two modes, leak detection and leak localization, and will trigger an alarm within seconds of exposure contact. The fast and accurate response of the sensor provides reliable fluid leak detection for pipelines, storage tanks, airports, pumps, and valves to detect and minimize any potential catastrophic damage.

  6. 46 CFR 38.15-10 - Leak detection systems-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Leak detection systems-T/ALL. 38.15-10 Section 38.15-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Special Requirements § 38.15-10 Leak detection systems—T/ALL. (a) A detection system shall be permanently installed...

  7. Evaluation method of leachate leaking from carcass burial site

    NASA Astrophysics Data System (ADS)

    Park, S.; Kim, H.; Lee, M.; Lee, K.; Kim, S.; Kim, M.; Kim, H.; Kim, T.; Han, J.

    2012-12-01

    More than 150,000 cattle carcasses and 3,140,000 pig carcasses were buried all over the nation in Korea because of 2010 outbreak of foot and mouth disease (FMD). Various disposal Techniques such as incineration, composting, rendering, and burial have been developed and applied to effectively dispose an animal carcass. Since a large number of carcasses should be disposed for a short-term period to prevent the spread of FMD virus, most of the carcasses were disposed by mass burial technique. However, a long-term management and monitoring of leachate discharges are required because mass burial can cause soil and groundwater contamination. In this study, we used key parameters related to major components of leachate such as NH4-N, NO3-N, Cl-, E.coli and electrical conductivity as potential leachate contamination indicator to determine leachate leakage from the site. We monitored 300 monitoring wells in both burial site and the monitoring well 5m away from burial sites to identify leachate leaking from burial site. Average concentration of NH3-N in 300 monitoring wells, both burial site and the well 5m away from burial sites, were 2,593 mg/L and 733 mg/L, respectively. 24% out of 300 monitoring wells showed higher than 10 mg/L NH4-N, 100 mg/L Cl- and than 800 μS/cm electrical conductivity. From this study, we set up 4 steps guidelines to evaluate leachate leakage like; step 1 : High potential step of leachate leakage, step 2 : Middle potential step of leachate leakage, step 3 : Low potential step of leachate leakage, step 4 : No leachate leakage. On the basis of this result, we moved 34 leachate leaking burial sites to other places safely and it is necessary to monitor continuously the monitoring wells for environmental protection and human health.

  8. Management of Cerebrospinal Fluid Leak following Posterior Cranial Fossa Surgery

    PubMed Central

    Altaf, Imran; Vohra, Anjum Habib; Shams, Shahzad

    2016-01-01

    Objective: Cerebrospinal fluid leakage remains a significant cause of morbidity following posterior fossa surgery, and its treatment remains a difficult problem. The aim of the study was to propose a treatment algorithm for its management. Methods: A retrospective, single-center study was conducted on 147 patients who underwent elective posterior fossa surgery for a variety of diseases. Patients with post operative CSF leakage had either been treated initially with conservative measures including re-suturing of the wound, with CSF lumbar drainage to be employed in case the CSF leakage didn’t stop, or the initial intervention was the institution of CSF lumbar drainage simultaneously with conservative measures. VP (ventriculo-peritoneal) shunt was done in patients with gross hydrocephalus on postoperative CT brain. Results: There were 25 (17%) cases of CSF leakage, including 24 incisional CSF leaks and one case of CSF otorrhea. In eight patients with incisional CSF leakage treated initially with conservative measures including re-suturing of the wound, CSF leakage stopped in only two cases. CSF lumbar drainage instituted later on in six cases with persistent leakage stopped the CSF leakage. In fourteen patients managed initially with re-suturing of the wound and concomitant CSF lumbar drainage, CSF leakage settled in all the cases. Two patients with gross hydrocephalus on post operative CT were managed successfully with VP shunt. Re-suturing of the wound with concomitant CSF lumbar drainage was found to be significantly associated (p=0.003) with the stoppage of CSF leakage, and the settlement of meningitis (p= 0.014). Conclusion: Incisional CSF leaks after posterior fossa surgery should be managed with re-suturing of the wound and concomitant CSF lumbar drainage, instead of an initial trial of conservative therapy alone. PMID:28083041

  9. Effect of dynamic random leaks on the monitoring accuracy of home mechanical ventilators: a bench study

    PubMed Central

    2013-01-01

    Background So far, the accuracy of tidal volume (VT) and leak measures provided by the built-in software of commercial home ventilators has only been tested using bench linear models with fixed calibrated and continuous leaks. The objective was to assess the reliability of the estimation of tidal volume (VT) and unintentional leaks in a single tubing bench model which introduces random dynamic leaks during inspiratory or expiratory phases. Methods The built-in software of four commercial home ventilators and a fifth ventilator-independent ad hoc designed external software tool were tested with two levels of leaks and two different models with excess leaks (inspiration or expiration). The external software analyzed separately the inspiratory and expiratory unintentional leaks. Results In basal condition, all ventilators but one underestimated tidal volume with values ranging between -1.5 ± 3.3% to -8.7% ± 3.27%. In the model with excess of inspiratory leaks, VT was overestimated by all four commercial software tools, with values ranging from 18.27 ± 7.05% to 35.92 ± 17.7%, whereas the ventilator independent-software gave a smaller difference (3.03 ± 2.6%). Leaks were underestimated by two applications with values of -11.47 ± 6.32 and -5.9 ± 0.52 L/min. With expiratory leaks, VT was overestimated by the software of one ventilator and the ventilator-independent software and significantly underestimated by the other three, with deviations ranging from +10.94 ± 7.1 to -48 ± 23.08%. The four commercial tools tested overestimated unintentional leaks, with values between 2.19 ± 0.85 to 3.08 ± 0.43 L/min. Conclusions In a bench model, the presence of unintentional random leaks may be a source of error in the measurement of VT and leaks provided by the software of home ventilators. Analyzing leaks during inspiration and expiration separately may reduce this source of error. PMID:24325396

  10. Temperature and Atomic Oxygen Effects on Helium Leak Rates of a Candidate Main Interface Seal

    NASA Technical Reports Server (NTRS)

    Penney, Nicholas; Wasowski, Janice L.; Daniels, Christopher C.

    2011-01-01

    Helium leak tests were completed to characterize the leak rate of a 54 in. diameter composite space docking seal design in support of the National Aeronautics and Space Administration s (NASA's) Low Impact Docking System (LIDS). The evaluated seal design was a candidate for the main interface seal on the LIDS, which would be compressed between two vehicles, while docked, to prevent the escape of breathable air from the vehicles and into the vacuum of space. Leak tests completed at nominal temperatures of -30, 20, and 50 C on untreated and atomic oxygen (AO) exposed test samples were examined to determine the influence of both test temperature and AO exposure on the performance of the composite seal assembly. Results obtained for untreated seal samples showed leak rates which increased with increased test temperature. This general trend was not observed in tests of the AO exposed specimens. Initial examination of collected test data suggested that AO exposure resulted in higher helium leak rates, however, further analysis showed that the differences observed in the 20 and 50 C tests between the untreated and AO exposed samples were within the experimental error of the test method. Lack of discernable trends in the test data prevented concrete conclusions about the effects of test temperature and AO exposure on helium leak rates of the candidate seal design from being drawn. To facilitate a comparison of the current test data with results from previous leak tests using air as the test fluid, helium leak rates were converted to air leak rates using standard conversion factors for viscous and molecular flow. Flow rates calculated using the viscous flow conversion factor were significantly higher than the experimental air leakage values, whereas values calculated using the molecular flow conversion factor were significantly lower than the experimentally obtained air leak rates. The difference in these sets of converted flow rates and their deviation from the

  11. [Definition of a leak model and derivation of formulas for quantifying the accompanying leak surfaces in the anesthetic system].

    PubMed

    von Hintzenstern, U; Berthold, G; Daun, S; Bäz, G

    1991-02-01

    Our intention was to conceive a simple model for the evaluation of well-defined leakages in the anesthetic breathing system. Utilization of any model requires a formula to calculate the corresponding leakage surfaces. METHOD. The leak is defined as the projection of a circle (radius r) onto the surface of a cylinder (radius R) in which anesthetic gas is flowing. If we remove the leakage surface from the cylinder and flatten it out this produces neither a circular nor an elliptic shape. We will develop an expression for the leakage surface depending on the two radii, r and R, in a two-dimensional coordinate system. RESULTS. Formulas (3), (4) and (5) can be used to compute leakage areas for our model. An analytic solution of the equations is impossible by the application of calculus, but a PC program for numeric integration can yield values with a sufficient degree of accuracy. Some results for well-defined leakages in breathing tubes (R = 11 mm) are shown. These show that the difference between the leakage area and the projected circle (radius r) can practically be neglected for some values of r. CONCLUSION. Leakages in most anesthetic breathing systems cause some gas loss. The main causes are leaking plug connections and screw joints. Damage to the breathing tubes or bellows is less significant. Part of the tidal volume will disperse into the environment via the leak. This might be hazardous for the patient because the breathing volume and inspiratory oxygen concentration are reduced and for the operating team because of air pollution. To examine how such parameters as flow, compliance and resistance cause loss of pressure and volume and variations in gas concentration in the case of leakages an appropriate model of practical use is needed. Application of the formulas derived from our model makes it possible to compare measurements gained from studying the impacts of leakages in cylindrical tubes of different diameters. By experimental research of pressure and

  12. Evaluation and refinement of leak-rate estimation models. Revision 1

    SciTech Connect

    Paul, D.D.; Ahmad, J.; Scott, P.M.; Flanigan, L.F.; Wilkowski, G.M.

    1994-06-01

    Leak-rate estimation models are important elements in developing a leak-beforebreak methodology in piping integrity and safety analyses. Existing thermalhydraulic and crack-opening-area models used in current leak-rate estimations have been incorporated into a single computer code for leak-rate estimation. The code is called SQUIRT, which stands for Seepage Quantification of Upsets In Reactor Tubes. The SQUIRT program has been validated by comparing its thermalhydraulic predictions with the limited experimental data that have been published on two-phase flow through slits and cracks, and by comparing its crack-opening-area predictions with data from the Degraded Piping Program. In addition, leak-rate experiments were conducted to obtain validation data for a circumferential fatigue crack in a carbon steel pipe girth weld.

  13. Detecting well casing leaks in Bangladesh using a salt spiking method.

    PubMed

    Stahl, M O; Ong, J B; Harvey, C F; Johnson, C D; Badruzzaman, A B M; Tarek, M H; van Geen, A; Anderson, J A; Lane, J W

    2014-09-01

    We apply fluid-replacement logging in arsenic-contaminated regions of Bangladesh using a low-cost, down-well fluid conductivity logging tool to detect leaks in the cased section of wells. The fluid-conductivity tool is designed for the developing world: it is lightweight and easily transportable, operable by one person, and can be built for minimal cost. The fluid-replacement test identifies leaking casing by comparison of fluid conductivity logs collected before and after spiking the wellbore with a sodium chloride tracer. Here, we present results of fluid-replacement logging tests from both leaking and non-leaking casing from wells in Araihazar and Munshiganj, Bangladesh, and demonstrate that the low-cost tool produces measurements comparable to those obtained with a standard geophysical logging tool. Finally, we suggest well testing procedures and approaches for preventing casing leaks in Bangladesh and other developing countries.

  14. Detecting well casing leaks in Bangladesh using a salt spiking method

    USGS Publications Warehouse

    Stahl, M.O.; Ong, J.B.; Harvey, C.F.; Johnson, C.D.; Badruzzaman, A.B.M.; Tarek, M.H.; VanGeen, A.; Anderson, J.A.; Lane, J.W.

    2014-01-01

    We apply fluid-replacement logging in arsenic-contaminated regions of Bangladesh using a low-cost, down-well fluid conductivity logging tool to detect leaks in the cased section of wells. The fluid-conductivity tool is designed for the developing world: it is lightweight and easily transportable, operable by one person, and can be built for minimal cost. The fluid-replacement test identifies leaking casing by comparison of fluid conductivity logs collected before and after spiking the wellbore with a sodium chloride tracer. Here, we present results of fluid-replacement logging tests from both leaking and non-leaking casing from wells in Araihazar and Munshiganj, Bangladesh, and demonstrate that the low-cost tool produces measurements comparable to those obtained with a standard geophysical logging tool. Finally, we suggest well testing procedures and approaches for preventing casing leaks in Bangladesh and other developing countries.

  15. Small-target leak detection for a closed vessel via infrared image sequences

    NASA Astrophysics Data System (ADS)

    Zhao, Ling; Yang, Hongjiu

    2017-03-01

    This paper focus on a leak diagnosis and localization method based on infrared image sequences. Some problems on high probability of false warning and negative affect for marginal information are solved by leak detection. An experimental model is established for leak diagnosis and localization on infrared image sequences. The differential background prediction is presented to eliminate the negative affect of marginal information on test vessel based on a kernel regression method. A pipeline filter based on layering voting is designed to reduce probability of leak point false warning. A synthesize leak diagnosis and localization algorithm is proposed based on infrared image sequences. The effectiveness and potential are shown for developed techniques through experimental results.

  16. Severe hypo-osmotic hyponatraemia due to chylous leak following radical neck dissection.

    PubMed

    Andreou, Zenon; Trinidade, Aaron; Shakeel, Muhammad; Argiris, Konstantin; Panesar, Jaan; Kothari, Prasad

    2013-03-01

    Chylous leak is a documented complication of radical neck dissection with well recognised morbidities, including wound breakdown, hypovolaemia and hypoalbuminaemia. Other less well-documented electrolyte imbalances can also ensue. We aim to raise awareness about hypo-osmotic hyponatraemia as a potentially fatal, commonly overlooked complication of high-output chylous leaks. Following identification of his hyponatraemia, this patient underwent successful management in the intensive therapy unit, followed by surgical repair of his chylous leak. Hypo-osmotic hyponatraemia as a complication of chylous leak is not well documented, is likely to be overlooked when present, and is potentially life-threatening. It should be sought after in any patient with a high-output chylous leak following neck dissection.

  17. Endoscopic Nasobiliary Drainage for Bile Leak Caused by Injury to the Ducts of Luschka.

    PubMed

    Ko, Soon Young; Lee, Jeong Rok; Wang, Joon Ho

    2017-02-25

    A 51-year-old man underwent laparoscopic cholecystectomy for gallbladder stones. He had developed fever, chills, and abdominal pain four days after the procedure. In the drain tube, bile was persistently observed. An endoscopic retrograde cholangiopancreatography (ERCP) showed a leakage from the small duct into the right intrahepatic duct. We determined that the bile leak was caused by an injury to the ducts of Luschka. An endoscopic sphincterotomy (ES) using a 5-F nasobiliary tube (NBT) was performed, and the leak was resolved in five days. Herein, we report a bile leak caused by an injury to the ducts of Luschka after laparoscopic cholecystectomy. The leak was treated with ES using 5-F NBT, and the resolution of the leak was confirmed without repeated endoscopy.

  18. The Relief of Unilateral Painful Thoracic Radiculopathy without Headache from Remote Spontaneous Spinal Cerebrospinal Fluid Leak

    PubMed Central

    Son, Byung-chul; Ha, Sang-woo; Lee, Si-hoon; Choi, Jin-gyu

    2016-01-01

    Spontaneous intracranial hypotension (SIH) caused by spontaneous spinal cerebrospinal fluid (CSF) leaks produces orthostatic headaches. Although upper arm pain or paresthesia is reportedly associated with SIH from spontaneous spinal CSF leak in the presence of orthostatic headache, low thoracic radicular pain due to spontaneous spinal CSF leak unassociated with postural headache is extremely rare. We report a 67-year-old female who presented with chronic, positional radicular right T11 pain. Computed tomography myelography showed a spontaneous lumbar spinal CSF leak at L2-3 and repeated lumbar epidural blood patches significantly alleviated chronic, positional, and lower thoracic radiculopathic pain. The authors speculate that a chronic spontaneous spinal CSF leak not severe enough to cause typical orthostatic headache or epidural CSF collection may cause local symptoms such as irritation of a remote nerve root. There might be considerable variabilities in the clinical features of SIH which can present a diagnostic challenge. PMID:27445613

  19. NDE of stainless steel and on-line leak monitoring of LWRs

    SciTech Connect

    Kupperman, D.S.; Claytor, T.N.; Mathieson, T.; Prine, D.W.

    1985-10-01

    The GARD/ANL acoustic leak detection system is under evaluation in the laboratory. Results of laboratory tests with simulated acoustic leak signals and acoustic signals from field-induced intergranular stress corrosion cracks (IGSCCs) indicate that cross-correlation techniques can be used to locate the position of a leak. Leaks from a 2-in. ball valve and a flange were studied and compared with leaks from IGSCCs and fatigue cracks. The dependence of acoustic signal on flow rate and frequency for the valve and the flange was comparable to that of fatigue cracks (thermal and mechanical) and different from that of IGSCCs. Two pipe-to-endcap weldments with overlays were examined. Because the amount of cracking in the specimens was limited, the emphasis was on trying understand the nature of crack overcalling. Four 60-mm-thick cast stainless steel plates with microstructures ranging from equiaxed to primarily columnar grains have been examined with ultrasonic waves. 13 refs., 23 figs.

  20. Role of Barium Swallow in Diagnosing Clinically Significant Anastomotic Leak following Esophagectomy

    PubMed Central

    Roh, Simon; Iannettoni, Mark D.; Keech, John C.; Bashir, Mohammad; Gruber, Peter J.; Parekh, Kalpaj R.

    2016-01-01

    Background Barium swallow is performed following esophagectomy to evaluate the anastomosis for detection of leaks and to assess the emptying of the gastric conduit. The aim of this study was to evaluate the reliability of the barium swallow study in diagnosing anastomotic leaks following esophagectomy. Methods Patients who underwent esophagectomy from January 2000 to December 2013 at our institution were investigated. Barium swallow was routinely done between days 5–7 to detect a leak. These results were compared to clinically determined leaks (defined by neck wound infection requiring jejunal feeds and or parenteral nutrition) during the postoperative period. The sensitivity and specificity of barium swallow in diagnosing clinically significant anastomotic leaks was determined. Results A total of 395 esophagectomies were performed (mean age, 62.2 years). The indications for the esophagectomy were as follows: malignancy (n=320), high-grade dysplasia (n=14), perforation (n=27), benign stricture (n=7), achalasia (n=16), and other (n=11). A variety of techniques were used including transhiatal (n=351), McKeown (n=35), and Ivor Lewis (n=9) esophagectomies. Operative mortality was 2.8% (n=11). Three hundred and sixty-eight patients (93%) underwent barium swallow study after esophagectomy. Clinically significant anastomotic leak was identified in 36 patients (9.8%). Barium swallow was able to detect only 13/36 clinically significant leaks. The sensitivity of the swallow in diagnosing a leak was 36% and specificity was 97%. The positive and negative predictive values of barium swallow study in detecting leaks were 59% and 93%, respectively. Conclusion Barium swallow is an insensitive but specific test for detecting leaks at the cervical anastomotic site after esophagectomy. PMID:27066433

  1. The International Space Station 2B Photovoltaic Thermal Control System (PVTCS) Leak: An Operational History

    NASA Technical Reports Server (NTRS)

    Vareha, Anthony N.

    2014-01-01

    As early as 2004, the Photovoltaic Thermal Control System (PVTCS) for the International Space Station's 2B electrical power channel began slowly leaking ammonia overboard. Initially, the operations strategy was "feed the leak," a strategy successfully put into action via Extra Vehicular Activity (EVA) during the STS-134 Space Shuttle mission. This recharge was to have allowed for continued power channel operation into 2014 or 2015, at which point another EVA would have been required. In mid-2012, the leak rate increased from 1.5lbm/year to approximately 5lbm/year. As a result, an EVA was planned and executed within a 5 week timeframe to drastically alter the architecture of the PVTCS via connection to an adjacent dormant thermal control system. This EVA, US EVA 20, was successfully executed on November 1, 2012 and left the 2B PVTCS in a configuration where the system was now being adequately cooled via a different radiator than what the system was designed to utilize. Data monitoring over the next several months showed that the isolated radiator had not been leaking, and the system itself continued to leak steadily until May 9th, 2013. It was on this day that the ISS crew noticed the visible presence of ammonia crystals escaping from the 2B channel's truss segment, signifying a rapid acceleration of the leak from 5lbm/year to 5lbm/day. Within 48 hours of the crew noticing the leak, US EVA 21 was in progress to replace the coolant pump - the only remaining replaceable leak source. This was successful, and telemetry monitoring has shown that indeed the coolant pump was the leak source and was thus isolated from the running 2B PVTCS. This paper will explore the management of the 2B PVTCS leak from the operations perspective.

  2. Neonatal air leak syndrome and the role of high-frequency ventilation in its prevention.

    PubMed

    Jeng, Mei-Jy; Lee, Yu-Sheng; Tsao, Pei-Chen; Soong, Wen-Jue

    2012-11-01

    Air leak syndrome includes pulmonary interstitial emphysema, pneumothorax, pneumomediastinum, pneumopericardium, pneumoperitoneum, subcutaneous emphysema, and systemic air embolism. The most common cause of air leak syndrome in neonates is inadequate mechanical ventilation of the fragile and immature lungs. The incidence of air leaks in newborns is inversely related to the birth weight of the infants, especially in very-low-birth-weight and meconium-aspirated infants. When the air leak is asymptomatic and the infant is not mechanically ventilated, there is usually no specific treatment. Emergent needle aspiration and/or tube drainage are necessary in managing tension pneumothorax or pneumopericardium with cardiac tamponade. To prevent air leak syndrome, gentle ventilation with low pressure, low tidal volume, low inspiratory time, high rate, and judicious use of positive end expiratory pressure are the keys to caring for mechanically ventilated infants. Both high-frequency oscillatory ventilation (HFOV) and high-frequency jet ventilation (HFJV) can provide adequate gas exchange using extremely low tidal volume and supraphysiologic rate in neonates with acute pulmonary dysfunction, and they are considered to have the potential to reduce the risks of air leak syndrome in neonates. However, there is still no conclusive evidence that HFOV or HFJV can help to reduce new air leaks in published neonatal clinical trials. In conclusion, neonatal air leaks may present as a thoracic emergency requiring emergent intervention. To prevent air leak syndrome, gentle ventilations are key to caring for ventilated infants. There is insufficient evidence showing the role of HFOV and HFJV in the prevention or reduction of new air leaks in newborn infants, so further investigation will be necessary for future applications.

  3. Detection and location of leaks in district heating steam systems: Survey and review of current technology and practices

    SciTech Connect

    Kupperman, D.S.; Raptis, A.C.; Lanham, R.N.

    1992-03-01

    This report presents the results of a survey undertaken to identify and characterize current practices for detecting and locating leaks in district heating systems, particular steam systems. Currently used technology and practices are reviewed. In addition, the survey was used to gather information that may be important for the application of acoustic leak detection. A few examples of attempts to locate leaks in steam and hot water pipes by correlation of acoustic signals generated by the leaks are also discussed.

  4. 40 CFR 60.483-2 - Alternative standards for valves-skip period leak detection and repair.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... period leak detection and repair. 60.483-2 Section 60.483-2 Protection of Environment ENVIRONMENTAL... Before November 7, 2006 § 60.483-2 Alternative standards for valves—skip period leak detection and repair... in light liquid service, as described in § 60.482-7. (2) After 2 consecutive quarterly leak...

  5. 40 CFR 60.483-2a - Alternative standards for valves-skip period leak detection and repair.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... period leak detection and repair. 60.483-2a Section 60.483-2a Protection of Environment ENVIRONMENTAL...-2a Alternative standards for valves—skip period leak detection and repair. (a)(1) An owner or..., as described in § 60.482-7a. (2) After 2 consecutive quarterly leak detection periods with...

  6. Analytical and experimental studies of leak location and environment characterization for the international space station

    NASA Astrophysics Data System (ADS)

    Woronowicz, Michael; Abel, Joshua; Autrey, David; Blackmon, Rebecca; Bond, Tim; Brown, Martin; Buffington, Jesse; Cheng, Edward; DeLatte, Danielle; Garcia, Kelvin; Glenn, Jodie; Hawk, Doug; Ma, Jonathan; Mohammed, Jelila; de Garcia, Kristina Montt; Perry, Radford; Rossetti, Dino; Tull, Kimathi; Warren, Eric

    2014-12-01

    The International Space Station program is developing a robotically-operated leak locator tool to be used externally. The tool would consist of a Residual Gas Analyzer for partial pressure measurements and a full range pressure gauge for total pressure measurements. The primary application is to demonstrate the ability to detect NH3 coolant leaks in the ISS thermal control system. An analytical model of leak plume physics is presented that can account for effusive flow as well as plumes produced by sonic orifices and thruster operations. This model is used along with knowledge of typical RGA and full range gauge performance to analyze the expected instrument sensitivity to ISS leaks of various sizes and relative locations ("directionality"). The paper also presents experimental results of leak simulation testing in a large thermal vacuum chamber at NASA Goddard Space Flight Center. This test characterized instrument sensitivity as a function of leak rates ranging from 1 lbm//yr. to about 1 lbm/day. This data may represent the first measurements collected by an RGA or ion gauge system monitoring off-axis point sources as a function of location and orientation. Test results are compared to the analytical model and used to propose strategies for on-orbit leak location and environment characterization using the proposed instrument while taking into account local ISS conditions and the effects of ram/wake flows and structural shadowing within low Earth orbit.

  7. A Novel Technique to Treat Air Leak Following Lobectomy: Intrapleural Infusion of Plasma

    PubMed Central

    Konstantinou, Froso; Potaris, Konstantinos; Syrigos, Konstantinos N.; Tsipas, Panteleimon; Karagkiouzis, Grigorios; Konstantinou, Marios

    2016-01-01

    Background Persistent air leak following pulmonary lobectomy can be very difficult to treat and results in prolonged hospitalization. We aimed to evaluate the efficacy of a new method of postoperative air leak management using intrapleurally infused fresh frozen plasma via the chest tube. Material/Methods Between June 2008 and June 2014, we retrospectively reviewed 98 consecutive patients who underwent lobectomy for lung cancer and postoperatively developed persistent air leak treated with intrapleural instillation of fresh frozen plasma. Results The study identified 89 men and 9 women, with a median age of 65.5 years (range 48–77 years), with persistent postoperative air leak. Intrapleural infusion of fresh frozen plasma was successful in stopping air leaks in 90 patients (92%) within 24 hours, and in 96 patients (98%) within 48 hours, following resumption of the procedure. In the remaining 2, air leak ceased at 14 and 19 days. Conclusions Intrapleural infusion of fresh frozen plasma is a safe, inexpensive, and remarkably effective method for treatment of persistent air leak following lobectomy for lung cancer. PMID:27079644

  8. Analytical and Experimental Studies of Leak Location and Environment Characterization for the International Space Station

    NASA Technical Reports Server (NTRS)

    Woronowicz, Michael; Abel, Joshua; Autrey, David; Blackmon, Rebecca; Bond, Tim; Brown, Martin; Buffington, Jesse; Cheng, Edward; DeLatte, Danielle; Garcia, Kelvin; Glenn, Jodie; Hawk, Doug; Ma, Jonathan; Mohammed, Jelila; Montt de Garcia, Kristina; Perry, Radford; Rossetti, Dino; Tull, Kimathi; Warren, Eric

    2014-01-01

    The International Space Station program is developing a robotically-operated leak locator tool to be used externally. The tool would consist of a Residual Gas Analyzer for partial pressure measurements and a full range pressure gauge for total pressure measurements. The primary application is to detect NH3 coolant leaks in the ISS thermal control system. An analytical model of leak plume physics is presented that can account for effusive flow as well as plumes produced by sonic orifices and thruster operations. This model is used along with knowledge of typical RGA and full range gauge performance to analyze the expected instrument sensitivity to ISS leaks of various sizes and relative locations ("directionality"). The paper also presents experimental results of leak simulation testing in a large thermal vacuum chamber at NASA Goddard Space Flight Center. This test characterized instrument sensitivity as a function of leak rates ranging from 1 lb-mass/yr. to about 1 lb-mass/day. This data may represent the first measurements collected by an RGA or ion gauge system monitoring off-axis point sources as a function of location and orientation. Test results are compared to the analytical model and used to propose strategies for on-orbit leak location and environment characterization using the proposed instrument while taking into account local ISS conditions and the effects of ram/wake flows and structural shadowing within low Earth orbit.

  9. Analytical and experimental studies of leak location and environment characterization for the international space station

    SciTech Connect

    Woronowicz, Michael; Blackmon, Rebecca; Brown, Martin; Abel, Joshua; Hawk, Doug; Autrey, David; Glenn, Jodie; Bond, Tim; Buffington, Jesse; Cheng, Edward; Ma, Jonathan; Rossetti, Dino; DeLatte, Danielle; Garcia, Kelvin; Mohammed, Jelila; Montt de Garcia, Kristina; Perry, Radford; Tull, Kimathi; Warren, Eric

    2014-12-09

    The International Space Station program is developing a robotically-operated leak locator tool to be used externally. The tool would consist of a Residual Gas Analyzer for partial pressure measurements and a full range pressure gauge for total pressure measurements. The primary application is to demonstrate the ability to detect NH{sub 3} coolant leaks in the ISS thermal control system. An analytical model of leak plume physics is presented that can account for effusive flow as well as plumes produced by sonic orifices and thruster operations. This model is used along with knowledge of typical RGA and full range gauge performance to analyze the expected instrument sensitivity to ISS leaks of various sizes and relative locations (“directionality”). The paper also presents experimental results of leak simulation testing in a large thermal vacuum chamber at NASA Goddard Space Flight Center. This test characterized instrument sensitivity as a function of leak rates ranging from 1 lb{sub m/}/yr. to about 1 lb{sub m}/day. This data may represent the first measurements collected by an RGA or ion gauge system monitoring off-axis point sources as a function of location and orientation. Test results are compared to the analytical model and used to propose strategies for on-orbit leak location and environment characterization using the proposed instrument while taking into account local ISS conditions and the effects of ram/wake flows and structural shadowing within low Earth orbit.

  10. Analytical study of the performance of a geomembrane leak detection system.

    PubMed

    Lugli, Francesco; Mahler, Claudio Fernando

    2016-05-01

    The electrical detection of leaks in geomembranes is a method that allows identifying leakage of contaminants in lined facilities (e.g. sanitary landfills, pollutant ponds, etc.). The procedure in the field involves placing electrodes above and below the geomembrane, to generate an electrical current, which in turn engenders an electric potential distribution in the protective layer (generally a clayey soil). The electric potential will be greater in areas with higher current density, i.e. near leaks. In this study, we combined models from the literature to carry out a parametric analysis to identify the variables that most influence the amplitude of the electrical signals produced by leaks. The basic hypothesis is that the electrical conduction phenomena in a liner system could be depicted by a direct current circuit. After determining the value of the current at the leak, we calculated the electric potential distribution according to the model of Darilek and Laine. This enabled analysing the sensitivity of the parameters, which can be useful in the design of landfills and facilitate the location of leaks. This study showed that geomembranes with low electrical resistance (owing to low thickness, low resistivity, or extensive area) can hinder the leak detection process. In contrast, low thickness and high resistivity of the protection layer magnify the leak signal.

  11. High sensitivity of spontaneous spike frequency to sodium leak current in a Lymnaea pacemaker neuron.

    PubMed

    Lu, T Z; Kostelecki, W; Sun, C L F; Dong, N; Pérez Velázquez, J L; Feng, Z-P

    2016-12-01

    The spontaneous rhythmic firing of action potentials in pacemaker neurons depends on the biophysical properties of voltage-gated ion channels and background leak currents. The background leak current includes a large K(+) and a small Na(+) component. We previously reported that a Na(+) -leak current via U-type channels is required to generate spontaneous action potential firing in the identified respiratory pacemaker neuron, RPeD1, in the freshwater pond snail Lymnaea stagnalis. We further investigated the functional significance of the background Na(+) current in rhythmic spiking of RPeD1 neurons. Whole-cell patch-clamp recording and computational modeling approaches were carried out in isolated RPeD1 neurons. The whole-cell current of the major ion channel components in RPeD1 neurons were characterized, and a conductance-based computational model of the rhythmic pacemaker activity was simulated with the experimental measurements. We found that the spiking rate is more sensitive to changes in the Na(+) leak current as compared to the K(+) leak current, suggesting a robust function of Na(+) leak current in regulating spontaneous neuronal firing activity. Our study provides new insight into our current understanding of the role of Na(+) leak current in intrinsic properties of pacemaker neurons.

  12. Analytical and Experimental Studies of Leak Location and Environment Characterization for the International Space Station

    NASA Technical Reports Server (NTRS)

    Woronowicz, Michael S.; Abel, Joshua C.; Autrey, David; Blackmon, Rebecca; Bond, Tim; Brown, Martin; Buffington, Jesse; Cheng, Edward; DeLatte, Danielle; Garcia, Kelvin; Glenn, Jodie; Hawk, Doug; Ma, Jonathan; Mohammed, Jelila; de Garcia, Kristina Montt; Perry, Radford; Rossetti, Dino; Tull, Kimathi; Warren, Eric

    2014-01-01

    The International Space Station program is developing a robotically-operated leak locator tool to be used externally. The tool would consist of a Residual Gas Analyzer for partial pressure measurements and a full range pressure gauge for total pressure measurements. The primary application is to detect NH3 coolant leaks in the ISS thermal control system.An analytical model of leak plume physics is presented that can account for effusive flow as well as plumes produced by sonic orifices and thruster operations. This model is used along with knowledge of typical RGA and full range gauge performance to analyze the expected instrument sensitivity to ISS leaks of various sizes and relative locations (directionality).The paper also presents experimental results of leak simulation testing in a large thermal vacuum chamber at NASA Goddard Space Flight Center. This test characterized instrument sensitivity as a function of leak rates ranging from 1 lbmyr. to about 1 lbmday. This data may represent the first measurements collected by an RGA or ion gauge system monitoring off-axis point sources as a function of location and orientation. Test results are compared to the analytical model and used to propose strategies for on-orbit leak location and environment characterization using the proposed instrument while taking into account local ISS conditions and the effects of ramwake flows and structural shadowing within low Earth orbit.

  13. Fuel Cross Leak of Direct Di-methyl-ether Fuel Cell

    NASA Astrophysics Data System (ADS)

    Tsutsumi, Yasuyuki; Nakano, Yasuhiro; Haraguchi, Tadao

    Fuel cross leak through a polymer electrolyte membrane of the direct dimethyl ether fuel cell (DDFC) was investigated and was found to be approximately one-tenth that of the direct methanol fuel cell (DMFC). Three phenomena known to appear in the DMFC were also observed in the DDFC. These were (1) fuel cross leak due to the diffusion which increases with the fuel concentration on an open circuit condition, (2) electro-osmotic cross leak, which increases with the current density and fuel concentration, and (3) decrease of fuel cross leak with the increase of the current density due to fuel consumption at low fuel concentration. The decreased fuel cross leak realized by using Nafion ®117 as a membrane and the low fuel concentration of 11% resulted in an increase of the Farady efficiency of the DDFC of up to 90% at a current density of 80mA/cm2. The CO2 quantity at the anode outlet of the operating DDFC was slightly less than 2 mol per 12 protons, as estimated from an electrochemical reaction on the anode. The CO2 quantity at the cathode outlet was also investigated. The CO2 cross leak increased with current density at every CO2 concentration and the diffusion appeared to be the dominant phenomenon of the CO2 cross leak.

  14. Autonomous Cryogenic Leak Detector for Improving Launch Site Operations

    NASA Technical Reports Server (NTRS)

    Goswami, Kisholoy

    2013-01-01

    NASA, military, and commercial satellite users need launch services that are highly reliable, less complex, easier to test, and cost effective. This project has developed a tapered optical fiber sensor for detecting hydrogen. The invention involves incorporating chemical indicators on the tapered end of an optical fiber using organically modified silicate nanomaterials. The Hazardous Gas Detection Lab (HGDL) at Kennedy Space Center is involved in the design and development of instrumentation that can detect and qualify various mission-critical chemicals. Historically, hydrogen, helium, nitrogen, oxygen, and argon are the first five gases of HGDL focus. The use of these cryogenic fluids in the area of propulsion offers challenges. Due to their extreme low temperatures, these fluids induce contraction of the materials they contact, a potential cause of leakage. Among them, hydrogen is of particular concern. Small sensors are needed in multiple locations without adding to the structural weight. The most vulnerable parts of the engine are the connection flanges on the transfer lines, which have to support cycles of large thermal amplitude. The thermal protection of the engine provides a closed area, increasing the likelihood of an explosive atmosphere. Thus, even a small leak represents an unacceptable hazardous condition during loading operations, in flight, or after an aborted launch. Tapered fibers were first fabricated from 1/1.3-mm core/cladding (silica/ plastic) optical fibers. Typically a 1-ft (approx. 30- cm) section of the 1-mm fiber is cut from the bundle and marked with a pen into five 2-.-in. (.5.7-cm) sections. A propane torch is applied at every alternate mark to burn the jacket and soften the glass core. While the core is softening, the two ends of the fiber are pulled apart slowly to create fine tapers of .- to .-in. (.6- to 12-mm) long on the 1-mm optical fiber. Following this, the non-tapered ends of the fibers are polished to a 0.3-micron finish

  15. Using airborne measurements and modelling to determine the leak rate of the Elgin platform in 2012

    NASA Astrophysics Data System (ADS)

    Mobbs, Stephen D.; Bauguitte, Stephane J.-B.; Wellpott, Axel; O'Shea, Sebastian

    2013-04-01

    On the 25th March 2012 the French multinational oil and gas company Total reported a gas leak at the Elgin gas field in the North Sea following an operation on well G4 on the wellhead platform. During operations to plug and decommission the well methane leaked out which lead to the evacuation of the platform. Total made immense efforts to quickly stop the leak and on the 16th May 2012 the company announced the successful "Top kill". The UK's National Centre for Atmospheric Science (NCAS) supported the Total response to the leak with flights of the Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 aircraft. Between the 3rd of April and the 4th of May five missions were flown. The FAAM aircraft was equipped with a Fast Greenhouse Gas Analyser (FGGA, Model RMT-200, Los Gatos Research Inc., US) to measure CH4 mixing ratios with an accuracy of 0.07±2.48 ppbv. The measurement strategy used followed closely NOAA's during the Deepwater Horizon (DWH) spill in the Gulf of Mexico in 2010. The basis of the method is to sample the cross-wind structure of the plume at different heights downwind of the source. The measurements were then fitted to a Gaussian dispersion model which allowed the calculation of the leak rate. The first mission was flown on the 30th March 2012 only 5 days after Total reported the leak. On this day maximum CH4 concentrations exceeded 2800 ppbv. The plume was very distinct and narrow especially near the platform (10km) and it showed almost perfect Gaussian characteristics. Further downwind the plume was split up into several filaments. On this day the CH4 leak rate was estimated to be 1.1 kg/s. Between the 1st and 2nd mission (03/04/2012) the leak rate decreased significantly to about 0.5 kg/s. From the 2nd flight onwards only a minor decrease in leak rate was calculated. The last mission - while the platform was still leaking - was flown on the 4th of May, when the leak rate was estimated to be 0.3 kg/s. The FAAM aircraft measurements

  16. Derivation of effectiveness-NTU method for heat exchangers with heat leak

    SciTech Connect

    William M. Soyars

    2001-11-01

    A powerful and useful method for heat exchanger analysis is the effectiveness-NTU method. The equations for this technique presented in textbooks, however, are limited to the case where all of the heat transfer occurs between the two fluid streams. In an application of interest to us, cryogenic heat exchangers, we wish to consider a heat leak term. Thus, we have derived equations for the {var_epsilon}-NTU method with heat leak involved. The cases to be studied include evaporators, condensers, and counter-flow, with heat leak both in and out.

  17. USING AN ADAPTER TO PERFORM THE CHALFANT-STYLE CONTAINMENT VESSEL PERIODIC MAINTENANCE LEAK RATE TEST

    SciTech Connect

    Loftin, B.; Abramczyk, G.; Trapp, D.

    2011-06-03

    Recently the Packaging Technology and Pressurized Systems (PT&PS) organization at the Savannah River National Laboratory was asked to develop an adapter for performing the leak-rate test of a Chalfant-style containment vessel. The PT&PS organization collaborated with designers at the Department of Energy's Pantex Plant to develop the adapter currently in use for performing the leak-rate testing on the containment vessels. This paper will give the history of leak-rate testing of the Chalfant-style containment vessels, discuss the design concept for the adapter, give an overview of the design, and will present results of the testing done using the adapter.

  18. Demonstration of rapid and sensitive module leak certification for Space Station Freedom

    NASA Technical Reports Server (NTRS)

    Dietz, R. N.; Goodrich, R. W.

    1991-01-01

    A leak detection and quantification demonstration using perflurocarbon tracer (PFT) technology was successfully performed at the NASA Marshall Space Flight Center on January 25, 1991. The real-time Dual Trap Analyzer (DTA) at one-half hour after the start of the first run gave an estimated leak rate of 0.7 mL/min. This has since been refined to be 1.15 (+ or -) 0.09 mL/min. The leak rates in the next three runs were determined to be 9.8 (+ or -) 0.7, -0.4 (+ or -) 0.3, and 76 (+ or -) 6 mL/min, respectively. The theory on leak quantification in the steady-state and time-dependent modes for a single zone test facility was developed and applied to the above determinations. The laboratory PFT analysis system gave a limit-of-detection (LOD) of 0.05 fL for ocPDCH. This is the tracer of choice and is about 100-fold better than that for the DTA. Applied to leak certification, the LOD is about 0.00002 mL/s (0.000075 L/h), a 5 order-of-magnitude improvement over the original leak certification specification. Furthermore, this limit can be attained in a measurement period of 3 to 4 hours instead of days, weeks, or months. A new Leak Certification Facility is also proposed to provide for zonal (three zones) determination of leak rates. The appropriate multizone equations, their solutions, and error analysis have already been derived. A new concept of seal-integrity certification has been demonstrated for a variety of controlled leaks in the range of module leak testing. High structural integrity leaks were shown to have a linear dependence of flow on (Delta)p. The rapid determination of leak rates at different pressures is proposed and is to be determined while subjecting the module to other external force-generating parameters such as vibration, torque, solar intensity, etc.

  19. Management of Chyle Leak after Head and Neck Surgery: Review of Current Treatment Strategies

    PubMed Central

    Shi, Haoran; Sinha, Uttam K.

    2017-01-01

    Chyle leak formation is an uncommon but serious sequela of head and neck surgery when the thoracic duct is inadvertently injured, particularly with the resection of malignancy low in the neck. The thoracic duct is the primary structure that returns lymph and chyle from the entire left and right lower half of the body. Chyle extravasation can result in delayed wound healing, dehydration, malnutrition, electrolyte disturbances, and immunosuppression. Prompt identification and treatment of a chyle leak are essential for optimal surgical outcome. In this article we will review the current treatment options for iatrogenic cervical chyle leaks. PMID:28203252

  20. An optical sensor for the detection of leaks from subsea pipelines and risers

    NASA Astrophysics Data System (ADS)

    McStay, D.; Kerlin, J.; Acheson, R.

    2007-07-01

    An optical sensor for the rapid detection of detect leaks of oil, hydraulic fluids or leak detection chemicals from underwater pipelines and risers is reported. The sensor is designed to be deployed on ROVs or AUVs for the rapid survey of underwater pipelines and risers. The system employs ultra-bright LEDs to project a sensing light beam into the water to allow real time detection of ppm concentration plumes of material leaking from pipelines or riser in real time. Typically the system is deployed on an ROV which inspects a pipeline at a height of 2-3m.

  1. Hanford Single-Shell Tank Leak Causes and Locations - 241-SX Farm

    SciTech Connect

    Girardot, Crystal L.; Harlow, Donald G.

    2014-01-08

    This document identifies 241-SX Tank Farm (SX Farm) leak causes and locations for the 100 series leaking tanks (241-SX-107, 241-SX-108, 241-SX-109, 241-SX-111, 241-SX-112, 241-SX-113, 241-SX-114, and 241-SX-115) identified in RPP-ENV-39658, Rev. 0, Hanford SX-Farm Leak Assessments Report. This document satisfies the SX Farm portion of the target (T04) in the Hanford Federal Facility Agreement and Consent Order milestone M-045-91F.

  2. Hanford Single-Shell Tank Leak Causes and Locations - 241-BY and 241-TY Farm

    SciTech Connect

    Girardot, Crystal L.; Harlow, Donald G.

    2014-09-04

    This document identifies 241-BY Tank Farm (BY Farm) and 241-TY Tank Farm (TY Farm) lead causes and locations for the 100 series leaking tanks (241-BY-103, 241-TY-103, 241-TY-104, 241-TY-105 and 241-TY-106) identified in RPP-RPT-43704, Hanford BY Farm Leak Assessments Report, and in RPP-RPT-42296, Hanford TY Farm Leak Assessments Report. This document satisfies the BY and TY Farm portion of the target (T04) in the Hanford Federal Facility Agreement and Consent Order milestone M-045-91F.

  3. Precision blood-leak detector with high long-time stability

    NASA Astrophysics Data System (ADS)

    Georgiadis, Christos; Kleuver, Wolfram

    1999-11-01

    With this publication a precision blood-leak-detector is presented. The blood-leak-detector is used for recognition of fractures in the dialyzer of a kidney-machine. It has to detect safely a blood flow of ml/min to exclude any risk for the patient. A lot of systems exist for blood-leak-detection. All of them use the same principle. They detect the light absorption in the dialyze fluid. The actual used detectors are inferior to the new developed sensor in resolution and long-time stability. Regular test of the existing systems and high failure rates are responsible for the high maintenance.

  4. Demonstration of rapid and sensitive module leak certification for space station freedom

    SciTech Connect

    Dietz, R.N.; Goodrich, R.W. )

    1991-03-01

    A leak detection and quantification demonstration using perflurocarbon tracer (PFT) technology was successfully performed at the NASA Marshall Space Flight Center on January 25, 1991. The real-time Dual Trap Analyzer (DTA) at one-half hour after the start of the first run gave an estimated leak rate of 0.7 mL/min. This has since been refined to be 1.15 {plus minus} 0.09 mL/min. The leak rates in the next three runs were determined to be 9.8 {plus minus} 0.7, {minus}0.4 {plus minus} 0.3, and 76 {plus minus} 6 mL/min, respectively. The theory on leak quantification in the steady-state and time-dependent modes for a single zone test facility was developed and applied to the above determinations. The laboratory PFT analysis system gave a limit-of-detection (LOD) of 0.05 fL for ocPDCH. This is the tracer of choice and is about 100-fold better than that for the DTA. Applied to leak certification, the LOD is about 0.00002 mL/s (0.000075 L/h), a 5 order-of-magnitude improvement over the original leak certification specification. Furthermore, this limit can be attained in a measurement period of 3 to 4 hours instead of days, weeks, or months. A new Leak Certification Facility is also proposed to provide for zonal (three zones) determination of leak rates. The appropriate multizone equations, their solutions, and error analysis have already been derived. A new concept of seal-integrity certification has been demonstrated for a variety of controlled leaks in the range of module leak testing. High structural integrity leaks were shown to have a linear dependence of flow on {Delta}p. The rapid determination of leak rates at different pressures is proposed and is to be determined while subjecting the module to other external force-generating parameters such as vibration, torque, solar intensity, etc. 13 refs.

  5. Demonstration of rapid and sensitive module leak certification for space station freedom. Final report

    SciTech Connect

    Dietz, R.N.; Goodrich, R.W.

    1991-03-01

    A leak detection and quantification demonstration using perflurocarbon tracer (PFT) technology was successfully performed at the NASA Marshall Space Flight Center on January 25, 1991. The real-time Dual Trap Analyzer (DTA) at one-half hour after the start of the first run gave an estimated leak rate of 0.7 mL/min. This has since been refined to be 1.15 {plus_minus} 0.09 mL/min. The leak rates in the next three runs were determined to be 9.8 {plus_minus} 0.7, {minus}0.4 {plus_minus} 0.3, and 76 {plus_minus} 6 mL/min, respectively. The theory on leak quantification in the steady-state and time-dependent modes for a single zone test facility was developed and applied to the above determinations. The laboratory PFT analysis system gave a limit-of-detection (LOD) of 0.05 fL for ocPDCH. This is the tracer of choice and is about 100-fold better than that for the DTA. Applied to leak certification, the LOD is about 0.00002 mL/s (0.000075 L/h), a 5 order-of-magnitude improvement over the original leak certification specification. Furthermore, this limit can be attained in a measurement period of 3 to 4 hours instead of days, weeks, or months. A new Leak Certification Facility is also proposed to provide for zonal (three zones) determination of leak rates. The appropriate multizone equations, their solutions, and error analysis have already been derived. A new concept of seal-integrity certification has been demonstrated for a variety of controlled leaks in the range of module leak testing. High structural integrity leaks were shown to have a linear dependence of flow on {Delta}p. The rapid determination of leak rates at different pressures is proposed and is to be determined while subjecting the module to other external force-generating parameters such as vibration, torque, solar intensity, etc. 13 refs.

  6. Compartment Syndrome as a Result of Systemic Capillary Leak Syndrome

    PubMed Central

    D'Egidio, Gianni; Wan, Cynthia; Baxter, Alan; Rosenberg, Hans

    2016-01-01

    Objective. To describe a single case of Systemic Capillary Leak Syndrome (SCLS) with a rare complication of compartment syndrome. Patient. Our patient is a 57-year-old male, referred to our hospital due to polycythemia (hemoglobin (Hgb) of 220 g/L), hypotension, acute renal failure, and bilateral calf pain. Measurements and Main Results. The patient required bilateral forearm, thigh, and calf fasciotomies during his ICU stay and continuous renal replacement therapy was instituted following onset of acute renal failure and oliguria. Ongoing hemodynamic (Norepinephrine and Milrinone infusion) and respiratory (ventilator) support in the ICU was provided until resolution of intravascular fluid extravasation. Conclusions. SCLS is an extremely rare disorder characterized by unexplained episodic capillary hyperpermeability, which causes shift of volume and protein from the intravascular space to the interstitial space. Patients present with significant hypotension, hemoconcentration, hypovolemia, and oliguria. Severe edema results from leakage of fluid and proteins into tissue. The most important part of treatment is maintaining stable hemodynamics, ruling out other causes of shock and diligent monitoring for complications. Awareness of the clinical syndrome with the rare complication of compartment syndrome may help guide investigations and diagnoses of these critically ill patients. PMID:27688917

  7. The sodium leak channel, NALCN, in health and disease

    PubMed Central

    Cochet-Bissuel, Maud; Lory, Philippe; Monteil, Arnaud

    2014-01-01

    Ion channels are crucial components of cellular excitability and are involved in many neurological diseases. This review focuses on the sodium leak, G protein-coupled receptors (GPCRs)-activated NALCN channel that is predominantly expressed in neurons where it regulates the resting membrane potential and neuronal excitability. NALCN is part of a complex that includes not only GPCRs, but also UNC-79, UNC-80, NLF-1 and src family of Tyrosine kinases (SFKs). There is growing evidence that the NALCN channelosome critically regulates its ion conduction. Both in mammals and invertebrates, animal models revealed an involvement in many processes such as locomotor behaviors, sensitivity to volatile anesthetics, and respiratory rhythms. There is also evidence that alteration in this NALCN channelosome can cause a wide variety of diseases. Indeed, mutations in the NALCN gene were identified in Infantile Neuroaxonal Dystrophy (INAD) patients, as well as in patients with an Autosomal Recessive Syndrome with severe hypotonia, speech impairment, and cognitive delay. Deletions in NALCN gene were also reported in diseases such as 13q syndrome. In addition, genes encoding NALCN, NLF- 1, UNC-79, and UNC-80 proteins may be susceptibility loci for several diseases including bipolar disorder, schizophrenia, Alzheimer's disease, autism, epilepsy, alcoholism, cardiac diseases and cancer. Although the physiological role of the NALCN channelosome is poorly understood, its involvement in human diseases should foster interest for drug development in the near future. Toward this goal, we review here the current knowledge on the NALCN channelosome in physiology and diseases. PMID:24904279

  8. Assessment of crack opening area for leak rates

    SciTech Connect

    Sharples, J.K.; Bouchard, P.J.

    1997-04-01

    This paper outlines the background to recommended crack opening area solutions given in a proposed revision to leak before break guidance for the R6 procedure. Comparisons with experimental and analytical results are given for some selected cases of circumferential cracks in cylinders. It is shown that elastic models can provide satisfactory estimations of crack opening displacement (and area) but they become increasingly conservative for values of L{sub r} greater than approximately 0.4. The Dugdale small scale yielding model gives conservative estimates of crack opening displacement with increasing enhancement for L{sub r} values greater than 0.4. Further validation of the elastic-plastic reference stress method for up to L{sub r} values of about 1.0 is presented by experimental and analytical comparisons. Although a more detailed method, its application gives a best estimate of crack opening displacement which may be substantially greater than small scale plasticity models. It is also shown that the local boundary conditions in pipework need to be carefully considered when evaluating crack opening area for through-wall bending stresses resulting from welding residual stresses or geometry discontinuities.

  9. Neurologic involvement in a child with systemic capillary leak syndrome.

    PubMed

    Sion-Sarid, Racheli; Lerman-Sagie, Tally; Blumkin, Lubov; Ben-Ami, Dominique; Cohen, Ilan; Houri, Sion

    2010-03-01

    Idiopathic systemic capillary leak syndrome (SCLS) is a rare and life-threatening disorder of unknown pathology. It is characterized by recurrent episodes of shock resulting from leakage of plasma, which is reflected by accompanying hemoconcentration, hypoalbuminemia, and edema. Since its first description (Clarkson B, Thompson D, Horwith M, Luckey A. Am J Med. 1960;29:193-216), there have been only 3 descriptions of children with the disorder. Familial cases have not been reported. Brain involvement has only been described for adults and with minimal radiologic findings. We report here an unusual case of an 8-year-old boy with multiple episodes of SCLS since the age of 5 months and an exceptional presentation characterized by substantial neurologic involvement with cerebellar edema and autonomic dysfunction. The patient's family history was remarkable for 8 more relatives with the disorder, including his sister who died during a similar episode in infancy and a first-degree cousin of his father who was diagnosed as suffering from recurrent episodes of SCLS. Our patient is, to our knowledge, the first patient with SCLS with a family history of the disorder. Additional genetic studies in the extended family might shed light on the pathogenesis of this rare disorder.

  10. Endoscopic modalities for upper gastrointestinal leaks, fistulae and perforations

    PubMed Central

    Yee, Gary; Saxena, Payal

    2015-01-01

    Abstract Background Endotherapy techniques are a recent addition to the suite of non‐surgical and minimally invasive strategies to manage patients with perforations, leaks and fistulae. The emergency nature of these conditions and the heterogeneity of pathologies encountered create difficulties when trying to select appropriate tools in these complex situations. The purpose of this article is to review experience at a tertiary academic centre, describe the various endoscopic tools available and the situations where they can be considered for use. Methods Single‐centre series and review of the published literature. Results Of 64 patients, 57 were successfully treated using endoscopic therapy, with surgery used only to provide drainage and suture fully covered metal stents in place to prevent migration. Discussion Selection of an appropriate endotherapy or stent for a patient with an oesophago‐gastric perforation or fistula requires an understanding of the anatomy and physiology underlying the patient's presentation and an understanding of the strengths and weaknesses of the available methods. Standard surgical principles of drainage, avoidance of distal obstruction and nutrition remain central to successful outcomes. A combination of surgical and endoscopic treatments may reduce the number of required treatments and can provide the ability to anchor fully covered stents to prevent them from migrating. PMID:26525773

  11. Multiple-feature extracting modules based leak mining system design.

    PubMed

    Cho, Ying-Chiang; Pan, Jen-Yi

    2013-01-01

    Over the years, human dependence on the Internet has increased dramatically. A large amount of information is placed on the Internet and retrieved from it daily, which makes web security in terms of online information a major concern. In recent years, the most problematic issues in web security have been e-mail address leakage and SQL injection attacks. There are many possible causes of information leakage, such as inadequate precautions during the programming process, which lead to the leakage of e-mail addresses entered online or insufficient protection of database information, a loophole that enables malicious users to steal online content. In this paper, we implement a crawler mining system that is equipped with SQL injection vulnerability detection, by means of an algorithm developed for the web crawler. In addition, we analyze portal sites of the governments of various countries or regions in order to investigate the information leaking status of each site. Subsequently, we analyze the database structure and content of each site, using the data collected. Thus, we make use of practical verification in order to focus on information security and privacy through black-box testing.

  12. Multiple-Feature Extracting Modules Based Leak Mining System Design

    PubMed Central

    Cho, Ying-Chiang; Pan, Jen-Yi

    2013-01-01

    Over the years, human dependence on the Internet has increased dramatically. A large amount of information is placed on the Internet and retrieved from it daily, which makes web security in terms of online information a major concern. In recent years, the most problematic issues in web security have been e-mail address leakage and SQL injection attacks. There are many possible causes of information leakage, such as inadequate precautions during the programming process, which lead to the leakage of e-mail addresses entered online or insufficient protection of database information, a loophole that enables malicious users to steal online content. In this paper, we implement a crawler mining system that is equipped with SQL injection vulnerability detection, by means of an algorithm developed for the web crawler. In addition, we analyze portal sites of the governments of various countries or regions in order to investigate the information leaking status of each site. Subsequently, we analyze the database structure and content of each site, using the data collected. Thus, we make use of practical verification in order to focus on information security and privacy through black-box testing. PMID:24453892

  13. Improving Quality of Seal Leak Test Product using Six Sigma

    NASA Astrophysics Data System (ADS)

    Luthfi Malik, Abdullah; Akbar, Muhammad; Irianto, Dradjad

    2016-02-01

    Seal leak test part is a polyurethane material-based product. Based on past data, defect level of this product was 8%, higher than the target of 5%. Quality improvement effort was done using six sigma method that included phases of define, measure, analyse, improve, and control. In the design phase, a Delphi method was used to identify factors that were critical to quality. In the measure phase, stability and process capability was measured. Fault tree analysis (FTA) and failure mode and effect analysis (FMEA) were used in the next phase to analize the root cause and to determine the priority issues. Improve phase was done by compiling, selecting, and designing alternative repair. Some improvement efforts were identified, i.e. (i) making a checklist for maintenance schedules, (ii) making written reminder form, (iii) modifying the SOP more detail, and (iv) performing a major service to the vacuum machine. To ensure the continuity of improvement efforts, some control activities were executed, i.e. (i) controlling, monitoring, documenting, and setting target frequently, (ii) implementing reward and punishment system, (iii) adding cleaning tool, and (iv) building six sigma organizational structure.

  14. 40 CFR 63.502 - Equipment leak and heat exchange system provisions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... pumps and agitator seals in light liquid service, shall not be considered a leak. For the purposes of... fluid used to provide lubrication and/or cooling of the pump or agitator shaft exits the pump,...

  15. 40 CFR 63.502 - Equipment leak and heat exchange system provisions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... pumps and agitator seals in light liquid service, shall not be considered a leak. For the purposes of... fluid used to provide lubrication and/or cooling of the pump or agitator shaft exits the pump,...

  16. Endoscopic Repair of Frontal Sinus Cerebrospinal Fluid Leaks after Firearm Injuries: Report of Two Cases

    PubMed Central

    Reyes, Camilo; Solares, C. Arturo

    2015-01-01

    Objectives To describe two cases of cerebrospinal fluid (CSF) leak repair after gunshot wound to the head. Design Retrospective review of two cases. Settings A large regional tertiary care facility. Participants Two patients with gunshot wounds to the skull base. Main Outcome Measures Preoperative and postoperative physical and radiologic findings. Results Patients in this series underwent endoscopic surgery, debridement, and repair of CSF leaks after gunshot wounds to the head. To date, the patients are without CSF leak. Conclusions Endoscopic closure of anterior skull base CSF leaks in patients with gunshot wounds can be safe and effective. Treatment should be decided by the severity of neurologic deterioration throughout the emergency period and the existence or absence of associated intracranial lesions. Timing for surgery should be decided with great care and with a multidisciplinary approach. PMID:26251818

  17. U.S. strategic petroleum reserve Big Hill 114 leak analysis 2012.

    SciTech Connect

    Lord, David L.; Roberts, Barry L.; Lord, Anna C. Snider; Sobolik, Steven Ronald; Park, Byoung Yoon; Rudeen, David Keith

    2013-06-01

    This report addresses recent well integrity issues related to cavern 114 at the Big Hill Strategic Petroleum Reserve site. DM Petroleum Operations, M&O contractor for the U.S. Strategic Petroleum Reserve, recognized an apparent leak in Big Hill cavern well 114A in late summer, 2012, and provided written notice to the State of Texas as required by law. DM has since isolated the leak in well A with a temporary plug, and is planning on remediating both 114 A- and B-wells with liners. In this report Sandia provides an analysis of the apparent leak that includes: (i) estimated leak volume, (ii) recommendation for operating pressure to maintain in the cavern between temporary and permanent fixes for the well integrity issues, and (iii) identification of other caverns or wells at Big Hill that should be monitored closely in light of the sequence of failures there in the last several years.

  18. Analysis of Pressurized Water Reactor Primary Coolant Leak Events Caused by Thermal Fatigue

    SciTech Connect

    Atwood, Corwin Lee; Shah, Vikram Naginbhai; Galyean, William Jospeh

    1999-09-01

    We present statistical analyses of pressurized water reactor (PWR) primary coolant leak events caused by thermal fatigue, and discuss their safety significance. Our worldwide data contain 13 leak events (through-wall cracking) in 3509 reactor-years, all in stainless steel piping with diameter less than 25 cm. Several types of data analysis show that the frequency of leak events (events per reactor-year) is increasing with plant age, and the increase is statistically significant. When an exponential trend model is assumed, the leak frequency is estimated to double every 8 years of reactor age, although this result should not be extrapolated to plants much older than 25 years. Difficulties in arresting this increase include lack of quantitative understanding of the phenomena causing thermal fatigue, lack of understanding of crack growth, and difficulty in detecting existing cracks.

  19. Study on effect of liquid level on the heat leak into vertical cryogenic vessels

    NASA Astrophysics Data System (ADS)

    Li, Yang; Wang, Rongshun; Wang, Caili

    2010-06-01

    The diminishing of heat leak into cryogenic vessels can prolong the storage time of cryogenic liquid. With the storage of cryogenic liquid reducing, the heat leak decreases, while the actual storage time increases. Compared with the theoretical analysis, the numerical simulation can more accurately calculate the heat transfer and temperature distribution in the vessel with complex structure. In this paper the steady state heat leak into cryogenic vessels with different liquid level height is analyzed using a finite element model. And liquid nitrogen boil-off method was adopted in experiments to validate the result of numerical simulation. Experimental results indicate favorable agreement with numerical simulation by ANSYS software. The effect of liquid level on heat leak into the cryogenic vessel can be considered in calculation of storage time and structure design.

  20. 75 FR 4134 - Pipeline Safety: Leak Detection on Hazardous Liquid Pipelines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-26

    ... Pipeline and Hazardous Materials Safety Administration Pipeline Safety: Leak Detection on Hazardous Liquid... this Advisory Bulletin to advise and remind hazardous liquid pipeline operators of the importance of... protecting people and the environment. The federal hazardous liquid pipeline safety regulations...

  1. Passive air cooling of liquid metal-cooled reactor with double vessel leak accommodation capability

    DOEpatents

    Hunsbedt, Anstein; Boardman, Charles E.

    1995-01-01

    A passive and inherent shutdown heat removal method with a backup air flow path which allows decay heat removal following a postulated double vessel leak event in a liquid metal-cooled nuclear reactor. The improved reactor design incorporates the following features: (1) isolation capability of the reactor cavity environment in the event that simultaneous leaks develop in both the reactor and containment vessels; (2) a reactor silo liner tank which insulates the concrete silo from the leaked sodium, thereby preserving the silo's structural integrity; and (3) a second, independent air cooling flow path via tubes submerged in the leaked sodium which will maintain shutdown heat removal after the normal flow path has been isolated.

  2. Leak detection in spacecraft using structure-borne noise with distributed sensors

    NASA Astrophysics Data System (ADS)

    Holland, Stephen D.; Roberts, Ron; Chimenti, D. E.; Strei, Michael

    2005-04-01

    We have developed and tested in the laboratory a method for in-orbit detection and location of air leaks in manned spacecraft that uses only a small number of sensors distributed arbitrarily on the inner surface of the spacecraft skin. Then, structure-borne ultrasound in the range of 300-600 kHz is monitored from each of the sensors. When cross correlations between measured sensor waveforms indicate the presence of a leak, these correlations are compared with a large dynamically generated database of simulated correlations to locate the the leak on the pressure vessel. A series of experimental tests were performed and at worst the method identified some false locations, but the true location of the leak always appeared.

  3. ORNL Develops Novel, Nontoxic System That Seeks Air Leaks in Occupied Buildings

    ScienceCinema

    Hun, Diana

    2016-12-14

    Oak Ridge National Laboratory scientists demonstrate their novel, nontoxic fluorescent air leak detection system that uses a vitamin- and water-based solution to quickly locate cracks in occupied buildings without damaging property.

  4. AIRBORNE, OPTICAL REMOTE SENSNG OF METHANE AND ETHANE FOR NATURAL GAS PIPELINE LEAK DETECTION

    SciTech Connect

    Jerry Myers

    2005-04-15

    Ophir Corporation was awarded a contract by the U. S. Department of Energy, National Energy Technology Laboratory under the Project Title ''Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipeline Leak Detection'' on October 14, 2002. The scope of the work involved designing and developing an airborne, optical remote sensor capable of sensing methane and, if possible, ethane for the detection of natural gas pipeline leaks. Flight testing using a custom dual wavelength, high power fiber amplifier was initiated in February 2005. Ophir successfully demonstrated the airborne system, showing that it was capable of discerning small amounts of methane from a simulated pipeline leak. Leak rates as low as 150 standard cubic feet per hour (scf/h) were detected by the airborne sensor.

  5. New acoustic techniques for leak detection in fossil fuel plant components

    NASA Astrophysics Data System (ADS)

    Parini, G.; Possa, G.

    Two on-line acoustic monitoring techniques for leak detection in feedwater preheaters and boilers of fossil fuel power plants are presented. The leak detection is based on the acoustic noise produced by the turbulent leak outflow. The primary sensors are piezoelectric pressure transducers, installed near the feedwater preheater inlets, in direct contact with the water, or mounted on boiler observation windows. The frequency band of the auscultation ranges from a few kHz, to 10 to 15 kHz. The signals are characterized by their rms value, continuously recorded by means of potentiometric strip chart recorders. The leak occurrence is signalled by the signal rms overcoming predetermined threshold levels. Sensitivity, reliability, acceptance in plant control practice, and costs-benefits balance are satisfactory.

  6. ORNL Develops Novel, Nontoxic System That Seeks Air Leaks in Occupied Buildings

    SciTech Connect

    Hun, Diana

    2016-12-06

    Oak Ridge National Laboratory scientists demonstrate their novel, nontoxic fluorescent air leak detection system that uses a vitamin- and water-based solution to quickly locate cracks in occupied buildings without damaging property.

  7. Development of cost effective fenceline monitoring methods to support advanced leak detection and repair strategies

    EPA Science Inventory

    Improved mitigation of fugitive emissions of hazardous air pollutants (HAPs), volatile organic compounds (VOCs), and greenhouse gas (GHG) emissions is an important emerging topic in many industrial sectors. Efficacious leak detection and repair (LDAR) programs of the future yiel...

  8. Minimally invasive management of anastomotic leak after bariatric Roux-en-Y gastric bypass.

    PubMed

    Ece, Ilhan; Yilmaz, Huseyin; Alptekin, Husnu; Acar, Fahrettin; Yormaz, Serdar; Sahin, Mustafa

    2015-01-01

    The aim of this retrospective study was to examine the anastomotic erosion due to drain and success of fibrin sealant in its management. Between 2013 and 2014, 102 patients underwent LRYGB and gastrojejunal anastomotic leak occurred due to drain erosion in 2 of them. The diagnosis was established with saliva drainage and was confirmed by upper gastrointestinal series. The absence of hemodynamic instability was directed us to conservative treatment. During the endoscopy, dehiscence was assessed and fibrin sealant was applied. The leaks healed progressively in a few days, and the drains removed within 6 days. Seven and 9 days later, the patients were discharged without any problem. Anastomotic leaks after bariatric surgery can cause severe morbidity, cost, and effects quality of life. Hemodynamically stable and drained patients are candidates for conservative methods. Endoscopic injection of fibrin sealant has been successful in closing gastric leaks.

  9. PLC Software Program for Leak Detector Station A1 SALW-LD-ST-A1

    SciTech Connect

    KOCH, M.R.

    2001-01-25

    This document describes the software program for the programmable logic controller for the leak detector station ''SALW-LD-ST-A1''. The appendices contains a copy of the printout of the software program.

  10. Passive air cooling of liquid metal-cooled reactor with double vessel leak accommodation capability

    DOEpatents

    Hunsbedt, A.; Boardman, C.E.

    1995-04-11

    A passive and inherent shutdown heat removal method with a backup air flow path which allows decay heat removal following a postulated double vessel leak event in a liquid metal-cooled nuclear reactor is disclosed. The improved reactor design incorporates the following features: (1) isolation capability of the reactor cavity environment in the event that simultaneous leaks develop in both the reactor and containment vessels; (2) a reactor silo liner tank which insulates the concrete silo from the leaked sodium, thereby preserving the silo`s structural integrity; and (3) a second, independent air cooling flow path via tubes submerged in the leaked sodium which will maintain shutdown heat removal after the normal flow path has been isolated. 5 figures.

  11. Highly sensitive gas leak detector based on a quartz-enhanced photoacoustic SF6 sensor.

    PubMed

    Sampaolo, Angelo; Patimisco, Pietro; Giglio, Marilena; Chieco, Leonardo; Scamarcio, Gaetano; Tittel, Frank K; Spagnolo, Vincenzo

    2016-07-11

    The implementation, performance validation, and testing of a gas-leak optical sensor based on mid-IR quartz-enhanced photoacoustic (QEPAS) spectroscopic technique is reported. A QEPAS sensor was integrated in a vacuum-sealed test station for mechatronic components. The laser source for the sensor is a quantum cascade laser emitting at 10.56 µm, resonant with a strong absorption band of sulfur hexafluoride (SF6), which was selected as a leak tracer. The minimum detectable concentration of the QEPAS sensor is 2.7 parts per billion with an integration time of 1 s, corresponding to a sensitivity of leak flows in the 10-9 mbar∙l/s range, comparable with state-of-the-art leak detection techniques.

  12. 46 CFR 38.15-10 - Leak detection systems-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... sense cargo leaks. The detectors shall be located within the space so as to permit the sensing of an... concentrations might be expected. (5) Cargo holds, containing pressure vessel type tanks and no cargo piping,...

  13. Incidence of cerebrospinal fluid leak following petrosectomy and analysis of avoidance techniques.

    PubMed

    Walcott, Brian P; Nahed, Brian V; Sarpong, Yaw; Kahle, Kristopher T; Sekhar, Laligam N; Ferreira, Manuel J

    2012-01-01

    A cerebrospinal fluid (CSF) leak following skull base surgery can lead to meningitis, impaired wound healing, and often requires re-operation and/or CSF diversion. Thirty-two patients underwent a presigmoid, transpetrosal approach to skull base aneurysms and tumors. A vascularized temporalis muscle flap was utilized during the closure of the initial skull base reconstruction in 18 of the 32 patients. A temporary CSF diversion was utilized in 23 of the 32 patients. A permanent shunt was placed in eight patients. One patient developed a postoperative CSF leak from the contralateral ear due to a congenital abnormality in the middle ear. Another patient, who did not have a vascularized temporalis muscle flap reconstruction, developed a postoperative CSF leak in the context of an operation for recurrent tumor and prior radiation treatment. CSF diversion and vascularized temporalis muscle flaps are effective in preventing the development of postoperative CSF leaks following petrosectomy.

  14. Leak-detection device is {open_quotes}all ears{close_quotes}

    SciTech Connect

    Malm, H.; Halpern, F.

    1996-04-01

    Ultrasonic detection devices for locating air or liquid leaks are described. Standard packages consist of a hand-held detection instrument, high-impedance headphones, a localization sound probe, an ultrasound transmitter, and a precision contact probe. The ultrasonic vibrations are converted into either an audible frequency or a digital readout. The use of ultrasonic devices in leak testing single-wall underground storage tanks is detailed.

  15. Risk factors for postoperative cerebrospinal fluid leak and meningitis after expanded endoscopic endonasal surgery.

    PubMed

    Ivan, Michael E; Iorgulescu, J Bryan; El-Sayed, Ivan; McDermott, Michael W; Parsa, Andrew T; Pletcher, Steven D; Jahangiri, Arman; Wagner, Jeffrey; Aghi, Manish K

    2015-01-01

    Postoperative cerebrospinal fluid (CSF) leak is a serious complication of transsphenoidal surgery, which can lead to meningitis and often requires reparative surgery. We sought to identify preoperative risk factors for CSF leaks and meningitis. We reviewed 98 consecutive expanded endoscopic endonasal surgeries performed from 2008-2012 and analyzed preoperative comorbidities, intraoperative techniques, and postoperative care. Univariate and multivariate analyses were performed. The most common pathologies addressed included pituitary adenoma, Rathke cyst, chordoma, esthesioneuroblastoma, meningioma, nasopharyngeal carcinoma, and squamous cell carcinoma. There were 11 CSF leaks (11%) and 10 central nervous system (CNS) infections (10%). Univariate and multivariate analysis of preoperative risk factors showed that patients with non-ideal body mass index (BMI) were associated with higher rate of postoperative CSF leak and meningitis (both p<0.01). Also, patients with increasing age were associated with increased CSF leak (p = 0.03) and the length of time a lumbar drain was used postoperatively was associated with infection in a univariate analysis. In addition, three of three endoscopic transsphenoidal surgeries combined with open cranial surgery had a postoperative CSF leak and CNS infection rate which was a considerably higher rate than for transsphenoidal surgeries alone or surgeries staged with open cases (p<0.01 and p=0.04, respectively) In this series of expanded endoscopic transsphenoidal surgeries, preoperative BMI remains the most important preoperative predictor for CSF leak and infection. Other risk factors include age, intraoperative CSF leak, lumbar drain duration, and cranial combined cases. Risks associated with complex surgical resections when combining open and endoscopic approaches could be minimized by staging these procedures.

  16. Air leak: An unusual manifestation of organizing pneumonia secondary to bleomycin

    PubMed Central

    Namitha, R; Nimisha, KP; Yusuf, Nasser; Rauf, CP

    2017-01-01

    Organizing pneumonia (OP) is a less common interstitial lung disease with varying clinical picture. The development of pulmonary air leak in a case of OP is an extremely rare complication. Here, we report the case of a 46-year-old female with carcinoma ovary, postchemotherapy who developed respiratory distress with pneumomediastinum, and subcutaneous emphysema. Lung biopsy showed evidence of OP. This turned out to be a rare case of OP, secondary to bleomycin chemotherapy, presenting with pulmonary air leak. PMID:28360468

  17. Using optical and microwave, modeled and airborne data to identify water leaks from rural aqueducts

    NASA Astrophysics Data System (ADS)

    Taylor, Frances M.; Malthus, Tim J.; Woodhouse, Iain H.; Hedger, Richard D.

    2003-03-01

    The development of techniques for the detection of water leaks from underground pipelines is seen as a high profile activity by water companies and regulators. This is due to increasing water demands and problems with current leak detection methods. In this paper optical reflectance and microwave backscatter models (SAIL + PROSPECT and RT2) were used to try and identify optimal indices for detecting water leaks amongst a variety of different land cover types at different growth stages. Results suggest that red/near infrared and red/middle infrared ratios show potential for leak detection. Given the sensitivity of L-band radar to moisture, and the ability to separate contributions from canopy and ground surface, it is possible to detect saturated soils through vegetation canopies. The results of both approaches are used to infer limits of detection in terms of season and meteorological conditions for a range of land covers. Preliminary findings suggest that leaks may be optimally detected when canopy height is low, surrounding soil is dry, and the leak has been present for more than 14 days. The modelled data is compared with L - band fully polarimetric E-SAR data, and 200 channel HYMAP hyperspectral airborne data which were acquired over an 8km section of the Vrynwy aqueduct (UK), which included a high concentration of leaks. Data was acquired as part of the British National Space Centre (BNSC) and Natural Environmental Research Council (NERC), SAR and Hyperspectral Airborne Campaign (SHAC) in June 2000. The results from this work suggest that remote sensing is both an effective and feasible tool for leak identification.

  18. Helium-neon lasers for remote measurements of natural gas leaks

    NASA Astrophysics Data System (ADS)

    1983-09-01

    A Differential Absorption Lidar (DIAL) system that at a distance of 15 meters can remotely sense natura gas (methane) leaks was developed. The system uses two helium-neon lasers (each emitting a different wavelength), a receiver, and an indium antimonide (InSb) photodetector cooled to 77 K. It is demonstrated the system can defect methane leaks both from an underground gas distribution system, and from sanitary landfills.

  19. Risks from Past, Current, and Potential Hanford Single Shell Tank Leaks

    SciTech Connect

    Triplett, Mark B.; Watson, David J.; Wellman, Dawn M.

    2013-05-24

    Due to significant delays in constructing and operating the Waste Treatment Plant, which is needed to support retrieval of waste from Hanford’s single shell tanks (SSTs), SSTs may now be required to store tank waste for two to three more decades into the future. Many SSTs were built almost 70 years ago, and all SSTs are well beyond their design lives. Recent examination of monitoring data suggests several of the tanks, which underwent interim stabilization a decade or more ago, may be leaking small amounts (perhaps 150–300 gallons per year) to the subsurface environment. A potential leak from tank T-111 is estimated to have released approximately 2,000 gallons into the subsurface. Observations of past leak events, recently published simulation results, and new simulations all suggest that recent leaks are unlikely to affect underlying groundwater above regulatory limits. However, these recent observations remind us that much larger source terms are still contained in the tanks and are also present in the vadose zone from historical intentional and unintentional releases. Recently there have been significant improvements in methods for detecting and characterizing soil moisture and contaminant releases, understanding and controlling mass-flux, and remediating deep vadose zone and groundwater plumes. To ensure extended safe storage of tank waste in SSTs, the following actions are recommended: 1) Improve capabilities for intrusion and leak detection. 2) Develop defensible conceptual models of intrusion and leak mechanisms. 3) Apply enhanced subsurface characterization methods to improve detection and quantification of moisture changes beneath tanks. 4) Maintain a flux-based assessment of past, present, and potential tank leaks to assess risks and to maintain priorities for applying mitigation actions. 5) Implement and maintain effective mitigation and remediation actions to protect groundwater resources. These actions will enable limited resources to be applied to

  20. Extinguishing in-flight engine fuel-leak fires with dry chemicals

    NASA Technical Reports Server (NTRS)

    Altman, R. L.

    1981-01-01

    The fire extinguishant storage temperature requirements were examined for several commercially available dry chemicals. Particular emphasis was placed on the development of dry powder extinguishant that, when discharged into a jet engine fuel leak fire, would stick to the hot surfaces. Moreover, after putting out the initial fire, these extinguishants would act as antireignition catalysts, even when the fuel continued to leak onto the heated surface.

  1. Experience with helium leak and thermal shocks test of SST-1 cryo components

    NASA Astrophysics Data System (ADS)

    Sharma, Rajiv; Nimavat, Hiren; Srikanth, G. L. N.; Bairagi, Nitin; Shah, Pankil; Tanna, V. L.; Pradhan, S.

    2012-11-01

    A steady state superconducting Tokamak SST-1 is presently under its assembly stage at the Institute for Plasma Research. The SST-1 machine is a family of Superconducting SC coils for both Toroidal field and Poloidal Field. An ultra high vacuum compatible vacuum vessel, placed in the bore of the TF coils, houses the plasma facing components. A high vacuum cryostat encloses all the SC coils and the vacuum vessel. Liquid Nitrogen (LN2) cooled thermal shield between the vacuum vessel & SC coils as well as between cryostat and the SC coils. There are number of crucial cryogenic components as Electrical isolators, 80 K thermal shield, Cryogenic flexible hose etc., which have to be passed the performance validation tests as part of fulfillment of the stringent QA/QC before incorporated in the main assembly. The individual leak tests of components at RT as well as after thermal cycle from 300 K to 77 K ensure us to make final overall leak proof system. These components include, Large numbers of Electrical Isolators for Helium as well as LN2 services, Flexible Bellows and Hoses for Helium as well as LN2 services, Thermal shock tests of large numbers of 80 K Bubble shields In order to validate the helium leak tightness of these components, we have used the calibrated mass spectrometer leak detector (MSLD) at 300 K, 77 K and 4.2. Since it is very difficult to locate the leaks, which are appearing at rather lower temperatures e.g. less than 20 K, We have invented different approaches to resolve the issue of such leaks. This paper, in general describes the design of cryogenic flexible hose, assembly, couplings for leak testing, test method and techniques of thermal cycles test at 77 K inflow conditions and leak testing aspects of different cryogenic components. The test results, the problems encountered and its solutions techniques are discussed.

  2. Leak Detection and H2 Sensor Development for Hydrogen Applications

    SciTech Connect

    Brosha, Eric L.

    2012-07-10

    The objectives of this report are: (1) Develop a low cost, low power, durable, and reliable hydrogen safety sensor for a wide range of vehicle and infrastructure applications; (2) Continually advance test prototypes guided by materials selection, sensor design, electrochemical R&D investigation, fabrication, and rigorous life testing; (3) Disseminate packaged sensor prototypes and control systems to DOE Laboratories and commercial parties interested in testing and fielding advanced prototypes for cross-validation; (4) Evaluate manufacturing approaches for commercialization; and (5) Engage an industrial partner and execute technology transfer. Recent developments in the search for sustainable and renewable energy coupled with the advancements in fuel cell powered vehicles (FCVs) have augmented the demand for hydrogen safety sensors. There are several sensor technologies that have been developed to detect hydrogen, including deployed systems to detect leaks in manned space systems and hydrogen safety sensors for laboratory and industrial usage. Among the several sensing methods electrochemical devices that utilize high temperature-based ceramic electrolytes are largely unaffected by changes in humidity and are more resilient to electrode or electrolyte poisoning. The desired sensing technique should meet a detection threshold of 1% (10,000 ppm) H{sub 2} and response time of {approx_equal}1 min, which is a target for infrastructure and vehicular uses. Further, a review of electrochemical hydrogen sensors by Korotcenkov et.al and the report by Glass et.al suggest the need for inexpensive, low power, and compact sensors with long-term stability, minimal cross-sensitivity, and fast response. This view has been largely validated and supported by the fuel cell and hydrogen infrastructure industries by the NREL/DOE Hydrogen Sensor Workshop held on June 8, 2011. Many of the issues preventing widespread adoption of best-available hydrogen sensing technologies available today

  3. Implications and Cost of Pancreatic Leak Following Distal Pancreatic Resection

    PubMed Central

    Rodríguez, J. Rubén; Germes, Santos Soto; Pandharipande, Pari V.; Gazelle, G. Scott; Thayer, Sarah P.; Warshaw, Andrew L.; Fernández-del Castillo, Carlos

    2014-01-01

    Objectives Pancreatic stump leak (PL) after elective distal pancreatic resection significantly impacts cost and increases subsequent health care resource utilization. We sought to provide an economic framework for potential interventions aimed at reducing its occurrence. Design Retrospective case series and economic evaluation. Setting University-affiliated, tertiary care referral center. Patients Sixty-six patients undergoing elective distal, pancreatectomy. Main Outcome Measures Postoperative complications; hospital and professional costs. Results Overall postoperative morbidity occurred in 34 patients (52%) with no deaths. The total number of patients with complications directly related to PL was 22 (33%). The mean ± SD number of total hospital days for the no-PL group was 5.2 ± 1.7 days (range, 3–12 days) vs 16.6 ± 14.6 days (range, 4–49 days) for the PL group (P = .001). The average patient with PL-related problems incurred a total cost that was 2.01 times greater than the average patient in the no-PL group. A decision analytic model developed to evaluate threshold costs showed that a hypothetical intervention designed to reduce the complication rate of distal pancreatectomy by one third would be financially justifiable up to a cost of $1418 per patient. Conclusions Complications derived from PL following distal pancreatectomy double the cost and dramatically increase health care resource utilization. There is an urgent need to develop strategies that reduce the incidence of this common complication. Interventions aimed at decreasing the incidence of PL should take into account this cost differential. We provide an economic model to serve as a guide for developing these technologies. PMID:16618893

  4. Distributed optical microsensors for hydrogen leak detection and related applications

    NASA Astrophysics Data System (ADS)

    Hunter, Scott R.; Patton, James F.; Sepaniak, Michael J.; Datskos, Panos G.; Smith, D. Barton

    2010-04-01

    Significant advances have recently been made to develop optically interrogated microsensor based chemical sensors with specific application to hydrogen vapor sensing and leak detection in the hydrogen economy. We have developed functionalized polymer-film and palladium/silver alloy coated microcantilever arrays with nanomechanical sensing for this application. The uniqueness of this approach is in the use of independent component analysis (ICA) and the classification techniques of neural networks to analyze the signals produced by an array of microcantilever sensors. This analysis identifies and quantifies the amount of hydrogen and other trace gases physisorbed on the arrays. Selectivity is achieved by using arrays of functionalized sensors with a moderate distribution of specificity among the sensing elements. The device consists of an array of beam-shaped transducers with molecular recognition phases (MRPs) applied to one surface of the transducers. Bending moments on the individual transducers can be detected by illuminating them with a laser or an LED and then reading the reflected light with an optical position sensitive detector (PSD) such as a CCD. Judicious selection of MRPs for the array provides multiple isolated interaction surfaces for sensing the environment. When a particular chemical agent binds to a transducer, the effective surface stresses of its modified and uncoated sides change unequally and the transducer begins to bend. The extent of bending depends upon the specific interactions between the microcantilever's MRP and the analyte. Thus, the readout of a multi-MRP array is a complex multidimensional signal that can be analyzed to deconvolve a multicomponent gas mixture. The use of this sensing and analysis technique in unattended networked arrays of sensors for various monitoring and surveillance applications is discussed.

  5. Non-Pyrotechnic Zero-Leak Normally Closed Valve

    NASA Technical Reports Server (NTRS)

    Gillespie, Rebecca

    2010-01-01

    This valve is designed to create a zero-leak seal in a liquid propulsion system that is a functional replacement for the normally closed pyrovalve. Unlike pyrovalves, Nitinol is actuated by simply heating the material to a certain temperature, called the transition temperature. Like a pyrovalve, before actuation, the upstream and downstream sections are separated from one another and from the external environment by closed welded seals. Also like pyrovalves, after actuation, the propellant or pressurant gas can flow without a significant pressure drop but are still separated from the external environment by a closed welded seal. During manufacture, a Nitinol bar is compressed to 93 percent of its original length and fitted tightly into the valve. During operation, the valve is heated until the Nitinol reaches the transition temperature of 95 C; the Nitinol "remembers" its previous longer shape with a very large recovery force causing it to expand and break the titanium parent metal seal to allow flow. Once open, the valve forever remains open. The first prototype valve was designed for high pressure [5,000 psi (=34.5 MPa)] and low flow, typical requirements for pressurant gas valves in liquid propulsion systems. It is possible to modify the dimensions to make low-pressure models or high-flow models, for use downstream of the propellant tanks. This design is simpler, lower risk, and less expensive than the pyrovalve. Although the valve must be in a thermally controlled state (kept below 80 C) to prevent premature actuation, the pyrovalves and electrically actuated initiators have far more taxing handling requirements.

  6. A LOW-COST GPR GAS PIPE & LEAK DETECTOR

    SciTech Connect

    David Cist; Alan Schutz

    2005-03-30

    A light-weight, easy to use ground penetrating radar (GPR) system for tracking metal/non-metal pipes has been developed. A pre-production prototype instrument has been developed whose production cost and ease of use should fit important market niches. It is a portable tool which is swept back and forth like a metal detector and which indicates when it goes over a target (metal, plastic, concrete, etc.) and how deep it is. The innovation of real time target detection frees the user from having to interpret geophysical data and instead presents targets as dots on the screen. Target depth is also interpreted automatically, relieving the user of having to do migration analysis. In this way the user can simply walk around looking for targets and, by ''connecting the dots'' on the GPS screen, locate and follow pipes in real time. This is the first tool known to locate metal and non-metal pipes in real time and map their location. This prototype design is similar to a metal detector one might use at the beach since it involves sliding a lightweight antenna back and forth over the ground surface. The antenna is affixed to the end of an extension that is either clipped to or held by the user. This allows him to walk around in any direction, either looking for or following pipes with the antenna location being constantly recorded by the positioning system. Once a target appears on the screen, the user can locate by swinging the unit to align the cursor over the dot. Leak detection was also a central part of this project, and although much effort was invested into its development, conclusive results are not available at the time of the writing of this document. Details of the efforts that were made as a part of this cooperative agreement are presented.

  7. Cyanoacrylate tissue glue for wound repair in early posttrabeculectomy conjunctival bleb leak: a case series

    PubMed Central

    Haslinda, Abdul-Rahim; Azhany, Yaakub; Noor-Khairul, Rasid; Zunaina, Embong; Liza-Sharmini, Ahmad-Tajudin

    2015-01-01

    We demonstrated a noninvasive management of early bleb leak following trabeculectomy using cyanoacrylate tissue glue (CATG). Three patients who underwent augmented trabeculectomy with mitomycin C with early bleb leak between January 2009 and June 2010 were reviewed. Case 1 and Case 2 exhibited bleb leak on postoperative Day 1 and Case 3 showed leak on follow-up at postoperative Day 7. Case 1 was successfully sealed with CATG at postoperative Day 3, after failed pressure padding and bandage contact lens. Case 2 was successfully sealed with CATG at postoperative Day 3, after failed pressure padding and conjunctiva flap resuturing. In Case 3, the leaking conjunctival flap was managed with combined techniques of resuturing and applying CATG at postoperative Day 9, after failed pressure padding. During leakage, the intraocular pressure was low (6–8 mmHg) in all three cases, with shallow anterior chamber depth and absence of other complications such as choroidal detachment, hypotony maculopathy, or endophthalmitis. Foreign body sensation was the main complaint following the procedure. No clinical allergy reaction was documented. CATG may serve as a potential adjunctive and effective method in the management of posttrabeculectomy early bleb leak. PMID:26229511

  8. The genetic-algorithm-enhanced blind system identification for water distribution pipeline leak detection

    NASA Astrophysics Data System (ADS)

    Yang, Jin; Wen, Yumei; Li, Ping

    2007-07-01

    The conventional leak location is based on the correlation of leak acoustic signals acquired spatially separately. By correlation, the time lag is estimated for localizing the leakage. In these methods, the detection distance is a prerequisite that has to be known beforehand. However, in practice, this prerequisite is not always satisfied. In this case, the correlation-based methods are not feasible. Actually, the acquired signals contain the characteristics related to the acoustic propagation channels; thus the blind system identification strategy is applied to estimate the transmission performances of acoustic channels. Then the times due to the propagation of the leak source signal travelling from the leak point to sensors are determined. In this way, for leak location, the detection distance is no longer a prerequisite. In blind system identification, due to the long impulse responses of the leak acoustic channels, the channels are inevitably ill conditioned and sensitive to the initial values. To overcome the ill conditions, the overlap-save and cross-correlation fitting techniques are utilized to identify the long impulse sequences under a built constraint. In order to avoid converging to the local minima, the genetic algorithm is used to minimize the cost functions. The practical detection results show the validity of the proposed scheme.

  9. Percutaneous Therapy of Ureteral Obstructions and Leak After Renal Transplantation: Long-Term Results

    SciTech Connect

    Aytekin, Cueneyt Boyvat, Fatih; Harman, Ali; Ozyer, Umut; Colak, Turan; Haberal, Mehmet

    2007-11-15

    The purpose of this study was to evaluate the long-term outcome of percutaneous therapy of ureteral complications after renal transplantation. Between January 2000 and June 2006 we percutaneously treated 26 renal transplant patients with ureteral obstruction (n=19) and leak (n=7). Obstructions were classified as early (<2 months after transplantation) or late (>2 months). Patients with leak were treated with nephro-ureteral catheter placement and subsequent double-J stenting. Balloon dilatation, stent placement, and basket extraction were used to treat ureteral obstructions. Patients were followed with ultrasonography. No major procedure-related complication occurred. The mean follow-up time was 34.3 months (range: 6 to 74 months). Initial clinical success was achieved in all 19 patients with obstruction and 6 of 7 patients with leak. Four of 9 early obstructions and 4 of 10 late obstructions recurred during the follow-up. All recurrences were initially managed again with percutaneous methods, including cutting balloon technique and metallic stent placement. Although there was no recurrence in patients with successfully treated leak, stricture was seen at the previous leak site in two patients. These strictures were also successfully managed percutaneously. We conclude that in the treatment of ureteral obstruction and leak following renal transplantation, percutaneous therapy is an effective alternative to surgery. However, further interventions are usually needed to maintain long-term patency.

  10. Covered Biodegradable Stent: New Therapeutic Option for the Management of Esophageal Perforation or Anastomotic Leak

    SciTech Connect

    Cerna, Marie; Koecher, Martin Valek, Vlastimil; Aujesky, Rene; Neoral, Cestmir; Andrasina, Tomas; Panek, Jiri; Mahathmakanthi, Shankari

    2011-12-15

    Purpose: This study was designed to evaluate our experience with the treatment of postoperative anastomotic leaks and benign esophageal perforations with covered biodegradable stents. Materials and Methods: From 2008 to 2010, we treated five men with either an anastomotic leak or benign esophageal perforation by implanting of covered biodegradable Ella-BD stents. The average age of the patients was 60 (range, 38-74) years. Postoperative anastomotic leaks were treated in four patients (1 after esophagectomy, 1 after resection of diverticulum, 2 after gastrectomy). In one patient, perforation occurred as a complication of the treatment of an esophageal rupture (which occurred during a balloon dilatation of benign stenosis) with a metallic stent. Results: Seven covered biodegradable stents were implanted in five patients. Primary technical success was 100%. Clinical success (leak sealing) was achieved in four of the five patients (80%). Stent migration occurred in three patients. In two of these patients, the leak had been sealed by the time of stent migration, therefore no reintervention was necessary. In one patient an additional stent had to be implanted. Conclusion: The use of biodegradable covered stents for the treatment of anastomotic leaks or esophageal perforations is technically feasible and safe. The initial results are promising; however, larger number of patients will be required to evaluate the capability of these biodegradable stents in the future. The use of biodegradable material for coverage of the stent is essential.

  11. Leak detection by acoustic emission monitoring. Phase 1. Feasibility study. Final report, August 1987-March 1988

    SciTech Connect

    Lichtenstein, B.; Winder, A.A.

    1994-05-26

    This investigation was conducted to determine the feasibility of detecting leaks from underground storage tanks or pipelines using acoustic emissions. An extensive technical literature review established that distinguishable acoustic emission signals will be generated when a storage tank is subjected to deformation stresses. A parametric analysis was performed which indicated that leak rates less than 0.1 gallons per hour can be detected for leak sizes less than 1/32 inch with 99% probability if the transient signals were sensed with an array of accelerometers (cemented to the tank or via acoustic waveguides), each having a sensitivity greater than 250 mv/g over a frequency range of 0.1 to 4000 Hz, and processed in a multi-channel Fourier spectrum analyzer with automatic threshold detection. An acoustic transient or energy release processor could conceivably detect the onset of the leak at the moment of fracture of the tank wall. The primary limitations to realizing reliable and robust acoustic emission monitoring of underground fluid leaks are the various masking noise sources prevalent at Air Force bases, which are attributed to aircraft, motor traffic, pump station operation, and ground tremors. Acoustic, Leak detection, Underground tank, Pipeline.

  12. Connective tissue spectrum abnormalities associated with spontaneous cerebrospinal fluid leaks: a prospective study.

    PubMed

    Reinstein, Eyal; Pariani, Mitchel; Bannykh, Serguei; Rimoin, David L; Schievink, Wouter I

    2013-04-01

    We aimed to assess the frequency of connective tissue abnormalities among patients with cerebrospinal fluid (CSF) leaks in a prospective study using a large cohort of patients. We enrolled a consecutive group of 50 patients, referred for consultation because of CSF leak. All patients have been carefully examined for the presence of connective tissue abnormalities, and based on findings, patients underwent genetic testing. Ancillary diagnostic studies included echocardiography, eye exam, and histopathological examinations of skin and dura biopsies in selected patients. We identified nine patients with heritable connective tissue disorders, including Marfan syndrome, Ehlers-Danlos syndrome and other unclassified forms. In seven patients, spontaneous CSF leak was the first noted manifestation of the genetic disorder. We conclude that spontaneous CSF leaks are associated with a spectrum of connective tissue abnormalities and may be the first noted clinical presentation of the genetic disorder. We propose that there is a clinical basis for considering spontaneous CSF leak as a clinical manifestation of heritable connective tissue disorders, and we suggest that patients with CSF leaks should be screened for connective tissue and vascular abnormalities.

  13. Accuracy improvement in the TDR-based localization of water leaks

    NASA Astrophysics Data System (ADS)

    Cataldo, Andrea; De Benedetto, Egidio; Cannazza, Giuseppe; Monti, Giuseppina; Demitri, Christian

    A time domain reflectometry (TDR)-based system for the localization of water leaks has been recently developed by the authors. This system, which employs wire-like sensing elements to be installed along the underground pipes, has proven immune to the limitations that affect the traditional, acoustic leak-detection systems. Starting from the positive results obtained thus far, in this work, an improvement of this TDR-based system is proposed. More specifically, the possibility of employing a low-cost, water-absorbing sponge to be placed around the sensing element for enhancing the accuracy in the localization of the leak is addressed. To this purpose, laboratory experiments were carried out mimicking a water leakage condition, and two sensing elements (one embedded in a sponge and one without sponge) were comparatively used to identify the position of the leak through TDR measurements. Results showed that, thanks to the water retention capability of the sponge (which maintains the leaked water more localized), the sensing element embedded in the sponge leads to a higher accuracy in the evaluation of the position of the leak.

  14. An Experimental Investigation of Leak Rate Performance of a Subscale Candidate Elastomer Docking Space Seal

    NASA Technical Reports Server (NTRS)

    Garafolo, Nicholas G.; Daniels, Christopher C.

    2011-01-01

    A novel docking seal was developed for the main interface seal of NASA s Low Impact Docking System (LIDS). This interface seal was designed to maintain acceptable leak rates while being exposed to the harsh environmental conditions of outer space. In this experimental evaluation, a candidate docking seal assembly called Engineering Development Unit (EDU58) was characterized and evaluated against the Constellation Project leak rate requirement. The EDU58 candidate seal assembly was manufactured from silicone elastomer S0383-70 vacuum molded in a metal retainer ring. Four seal designs were considered with unique characteristic heights. The leak rate performance was characterized through a mass point leak rate method by monitoring gas properties within an internal control volume. The leakage performance of the seals were described herein at representative docking temperatures of -50, +23, and +50 C for all four seal designs. Leak performance was also characterized at 100, 74, and 48 percent of full closure. For all conditions considered, the candidate seal assemblies met the Constellation Project leak rate requirement.

  15. Endoscopic treatment of leak at the tip of the “J” ileal pouch

    PubMed Central

    Kochhar, Gursimran Singh; Shen, Bo

    2017-01-01

    Background and study aims The tip of the “J” of the ileal pouch is the vulnerable location for leak after restorative proctocolectomy, which has normally been treated with surgery. We aimed to describe a novel endoscopic method to treat the same. Patients and methods A cohort of 12 consecutive patients with a leak at the tip of the “J” was identified in our prospectively maintained Pouch Registry. The endoscopic over-the-scope clipping (OTSC) system was used for the closure of the leak. Results Eight patients (66.6 %) achieved complete closure of the leak documented by endoscopy confirmed with guidewire and/or contrasted pouchogram, with 6 requiring a single endoscopic session and 2 undergoing a repeat session. Four patients (33.3 %) had a persistent leak and required surgical intervention, of whom 1 developed abscess in the pre-spine region 14 days after the endoscopic procedure and underwent pouch revision surgery. Conclusions OSTC appears to be safe and effective in treating the leak at the tip of the “J” in the majority of patients. PMID:28180150

  16. Viscous flow effects on hydrogen leaks from cracks in the Orbiter Challenger main engines

    NASA Technical Reports Server (NTRS)

    Goodrich, W. D.

    1984-01-01

    An analytical model was developed to provide additional insight and understanding of the factors that influence the simulation and prediction of leak rates from small cracks in pressurized containers. Specifically, the analysis was aimed at developing an analytical model capable of predicting the hydrogen leak rates from a crack in the combustion chamber coolant discharge manifold on main engine 1 of the Orbiter Challenger that was discovered during flight readiness firings 1 and 2. This model was based on viscous pipe flow analyses and calibrated for the crack geometry by using helium leak-rate data obtained from both low- and high-pressure tests used to simulate the flight readiness firing test conditions. In addition, this model includes the effects of crack width changes caused by different working stresses associated with the different test conditions. Because of the combination of the small crack dimensions and the wide range of pressures used for the test conditions, either laminar or turbulent viscous effects dominated the flows at all test conditions. This model was used to illustrate the sensitivity of the predicted leak rates to considerations of test conditions, viscous flow effects, and geometric features of the crack. In addition, the model was certified by comparing the hydrogen leak-rate prediction for the flight readiness firing test condition to the actual measured leak rate. The prediction was within 9 percent of the measured value.

  17. Dural Defect Repair in Translabyrinthine Acoustic Neuroma Surgery and Its Implications in Cerebrospinal Fluid Leak Occurrence

    PubMed Central

    Netto, Aloysio Augusto Tahan de Campos; Colafêmina, José Fernando; Centeno, Ricardo Silva

    2012-01-01

    Cerebrospinal fluid (CSF) leak is a complication that may occur after translabyrinthine (translab) acoustic neuroma (AN) removal. The aim of this study is to verify the incidence of CSF leak using two techniques for dural defect closure in translab AN surgery and present a new technique for dural repair. A retrospective study was held, reviewing charts of 34 patients in a tertiary neurotologic referral center. Out of these 34 patients that underwent translab AN excision in a 1-year period, 18 had their dural defect repaired using only abdominal fat graft and 16 using synthetic dura substitute (SDS) plus abdominal fat tissue. One patient (5.5%) in the first group had CSF leak and 1 (6.2%) in the second group had CSF leak postoperatively. Our data suggest that there are no significant differences in CSF leak rates using both techniques, although studies in a larger series must be undertaken to conclude it. We believe that the development of some points in the new technique for dural repair can achieve better results and reduce the CSF leak incidence in the translabyrinthine acoustic neuroma surgery in the near future. PMID:24083124

  18. Preliminary study of the use of radiotracers for leak detection in industrial applications

    NASA Astrophysics Data System (ADS)

    Wetchagarun, S.; Petchrak, A.; Tippayakul, C.

    2015-05-01

    One of the most widespread uses of radiotracers in the industrial applications is the leak detection of the systems. This technique can be applied, for example, to detect leak in heat exchangers or along buried industrial pipelines. The ability to perform online investigation is one of the most important advantages of the radiotracer technique over other non-radioactive leak detection methods. In this paper, a preliminary study of the leak detection using radiotracer in the laboratory scale was presented. Br-82 was selected for this work due to its chemical property, its suitable half-life and its on-site availability. The NH4Br in the form of aqueous solution was injected into the experimental system as the radiotracer. Three NaI detectors were placed along the pipelines to measure system flow rate and to detect the leakage from the piping system. The results obtained from the radiotracer technique were compared to those measured by other methods. It is found that the flow rate obtained from the radiotracer technique agreed well with the one obtained from the flow meter. The leak rate result, however, showed discrepancy between results obtained from two different measuring methods indicating further study on leak detection was required before applying this technique in the industrial system.

  19. Standoff gas leak detectors based on tunable diode laser absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Frish, M. B.; Wainner, R. T.; Green, B. D.; Laderer, M. C.; Allen, M. G.

    2005-11-01

    Trace gas sensing and analysis by Tunable Diode Laser Absorption Spectroscopy (TDLAS) has become a robust and reliable technology accepted for industrial process monitoring and control, quality assurance, environmental sensing, plant safety, and infrastructure security. Sensors incorporating well-packaged wavelength-stabilized near-infrared (1.2 to 2.0 μm) laser sources sense over a dozen toxic or industrially-important gases. A large emerging application for TDLAS is standoff sensing of gas leaks, e.g. from natural gas pipelines. The Remote Methane Leak Detector (RMLD), a handheld standoff TDLAS leak survey tool that we developed, is replacing traditional leak detection tools that must be physically immersed within a leak to detect it. Employing a 10 mW 1.6 micron DFB laser, the RMLD illuminates a non-cooperative topographic surface, up to 30 m distant, and analyzes returned scattered light to deduce the presence of excess methane. The eye-safe, battery-powered, 6-pound handheld RMLD enhances walking pipeline survey rates by more than 30%. When combined with a spinning or rastering mirror, the RMLD serves as a platform for mobile leak mapping systems. Also, to enable high-altitude surveying and provide aerial disaster response, we are extending the standoff range to 3000 m by adding an EDFA to the laser transmitter.

  20. 40 CFR 265.196 - Response to leaks or spills and disposition of leaking or unfit-for-use tank systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... release and, based upon that inspection: (1) Prevent further migration of the leak or spill to soils or surface water; and (2) Remove, and properly dispose of, any visible contamination of the soil or surface...; (ii) Characteristics of the surrounding soil (soil composition, geology, hydrogeology, climate);...