Science.gov

Sample records for leake enric plaza

  1. The design of a toll plaza

    NASA Astrophysics Data System (ADS)

    Dong, Haibin

    2017-04-01

    In this paper, a model is established to find the optimal shape, size and merging pattern of the toll plaza. The main work is how to take the aspects such as the accident prevention, throughput and cost into consideration to make the model of the toll plaza optimal. By analyzing the match of the number of tollbooths (B) and travel lanes (L) considering safety and cost, the optimal toll plaza model is established when the traffic flow is given.

  2. 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)

  3. Leak Detector

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Ni-Tec unit is a modified version of the Lixiscope, a small, battery-powered, portable X-ray instrument. Unit is used as a portable device capable of detecting radioactive leakage. If there were a leak, the radioactivity would illuminate the units viewing screen and identify the source of the leak; in the absence of radioactivity the screen shows nothing.

  4. CSF leak

    MedlinePlus

    ... rarely). Drainage of CSF from the nose (rarely). Exams and Tests The health care provider will perform ... usually recommended. Drinking more fluids, especially drinks with caffeine, can help slow or stop the leak and ...

  5. 46. View of Plaza de Armas taken through archway between ...

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

    46. View of Plaza de Armas taken through archway between Plaza de Armas and Carmen Bastion, looking southwest - Castillo de San Felipe del Morro, Northwest end of San Juan, San Juan, San Juan Municipio, PR

  6. 11. MECHANICAL ROOM BELOW GARAGE LEVEL OF TOLL PLAZA, LOOKING ...

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

    11. MECHANICAL ROOM BELOW GARAGE LEVEL OF TOLL PLAZA, LOOKING NORTH, SHOWING AURORA PUMPS AND BELL & GOSSETT HEATERS FOR ABANDONED SNOW-MELT SYSTEM. - Chicago Skyway Toll Bridge, Toll Plaza & Service Building, 8801 South Anthony Avenue, Chicago, Cook County, IL

  7. Democracy Plaza: A Campus Space for Civic Engagement

    ERIC Educational Resources Information Center

    Goldfinger, Johnny

    2009-01-01

    This article examines "Democracy Plaza," a campus space dedicated to written and spoken communication about issues of public concern. The Plaza gives students opportunities to become civically engaged through self-expression and the exchange of ideas. A series of chalkboards on the Plaza allows them to write their thoughts and read the comments of…

  8. 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

  9. WHITE HOUSE DEPARTMENT STORE AND MILLS BUILDING, 127 PIONEER PLAZA ...

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

    WHITE HOUSE DEPARTMENT STORE AND MILLS BUILDING, 127 PIONEER PLAZA AND 393 N. OREGON ST., LOOKING NORTH - South El Paso Street Historic District, South El Paso, South Oregon & South Santa Fe Streets, El Paso, El Paso County, TX

  10. 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

  11. 30. VIEW OF SOUTH END OF EAST SHED, PLAZA LEVEL, ...

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

    30. VIEW OF SOUTH END OF EAST SHED, PLAZA LEVEL, SHOWING BAGGAGE BRIDGE AND ITS RELATIONSHIP TO THE ELEVATORS AND PLATFORM - Pennsylvania Railroad, Harrisburg Station & Trainshed, Market & South Fourth Streets, Harrisburg, Dauphin County, PA

  12. 95. Pioneer Plaza, 125 (movie theater), entrance to theater and ...

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

    95. Pioneer Plaza, 125 (movie theater), entrance to theater and building to left of theater - South El Paso Street Historic District, South El Paso, South Oregon & South Santa Fe Streets, El Paso, El Paso County, TX

  13. Granite Monument Plaza Oklahoma City Civic Center, Bounded by ...

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

    Granite Monument Plaza - Oklahoma City Civic Center, Bounded by N. Shartel Avenue to the West, N. Hudson Avenue to the East, Couch Drive to the North, and Colcord Drive to the South, Oklahoma City, Oklahoma County, OK

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Using Behavioral Research to Assist in the Redesign of University Plazas

    ERIC Educational Resources Information Center

    Amsden, Daniel J.

    2005-01-01

    This article looks at how behavioral research can be an effective tool to use during the redesign process of university plazas. It also summarizes the research that was conducted at University Union Plaza at California Polytechnic State University (Cal Poly), a 30-year-old plaza that is scheduled to be redesigned. Through the use of behavioral…

  2. 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

  3. 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.

  4. Henry Hudson Bridge toll plaza, upper level, looking west. Pipe ...

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

    Henry Hudson Bridge toll plaza, upper level, looking west. Pipe railing parapets and pedestrian walkway on left. Inwood Hill Park in background. - Henry Hudson Parkway, Extending 11.2 miles from West 72nd Street to Bronx-Westchester border, New York County, NY

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Low Level Leaks

    NASA Technical Reports Server (NTRS)

    1998-01-01

    NASA has transferred the improved portable leak detector technology to UE Systems, Inc.. This instrument was developed to detect leaks in fluid systems of critical launch and ground support equipment. This system incorporates innovative electronic circuitry, improved transducers, collecting horns, and contact sensors that provide a much higher degree of reliability, sensitivity and versatility over previously used systems. Potential commercial uses are pipelines, underground utilities, air-conditioning systems, petrochemical systems, aerospace, power transmission lines and medical devices.

  15. Leaks in pipe networks

    USGS Publications Warehouse

    Pudar, Ranko S.; Liggett, James A.

    1992-01-01

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

  16. 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.

  17. A Guide to the PLAZA 3.0 Plant Comparative Genomic Database.

    PubMed

    Vandepoele, Klaas

    2017-01-01

    PLAZA 3.0 is an online resource for comparative genomics and offers a versatile platform to study gene functions and gene families or to analyze genome organization and evolution in the green plant lineage. Starting from genome sequence information for over 35 plant species, precomputed comparative genomic data sets cover homologous gene families, multiple sequence alignments, phylogenetic trees, and genomic colinearity information within and between species. Complementary functional data sets, a Workbench, and interactive visualization tools are available through a user-friendly web interface, making PLAZA an excellent starting point to translate sequence or omics data sets into biological knowledge. PLAZA is available at http://bioinformatics.psb.ugent.be/plaza/ .

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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…

  3. 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…

  4. 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.

  5. 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.

  6. Natural gas leak mapper

    DOEpatents

    Reichardt, Thomas A.; Luong, Amy Khai; Kulp, Thomas J.; Devdas, Sanjay

    2008-05-20

    A system is described that is suitable for use in determining the location of leaks of gases having a background concentration. The system is a point-wise backscatter absorption gas measurement system that measures absorption and distance to each point of an image. The absorption measurement provides an indication of the total amount of a gas of interest, and the distance provides an estimate of the background concentration of gas. The distance is measured from the time-of-flight of laser pulse that is generated along with the absorption measurement light. The measurements are formated into an image of the presence of gas in excess of the background. Alternatively, an image of the scene is superimosed on the image of the gas to aid in locating leaks. By further modeling excess gas as a plume having a known concentration profile, the present system provides an estimate of the maximum concentration of the gas of interest.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. CEMETERY CENTRAL PLAZA, SHOWING ROSTRUM AT RIGHT BACK¬GROUND AND MEMORIAL ...

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

    CEMETERY CENTRAL PLAZA, SHOWING ROSTRUM AT RIGHT BACK¬GROUND AND MEMORIAL TO PURSUERS OF LINCOLN’S ASSASSIN AT LEFT FORE¬GROUND. VIEW TO SOUTHWEST. - Alexandria National Cemetery, 1450 Wilkes Street, Alexandria, Independent City, VA

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. [Leak monitoring in noninvasive ventilation].

    PubMed

    Rabec, C A; Reybet-Degat, O; Bonniaud, P; Fanton, A; Camus, P

    2004-11-01

    Nasal mask ventilation has been shown to be effective, but outcomes do not always match expectations because of mouth leaks, patient-ventilator asynchrony, or decreased upper airway patency. These developments are detected when they lead ultimately to circuit leaks that lower the effectiveness of ventilation through pressure loss, poor inspiratory triggering, and prolonged inspiratory time. The quality of sleep is affected, and adverse effects and treatment intolerance may arise. A number of ways to detect leaks and their practical consequences are proposed in this article. We applied 310 leak-detection procedures to 177 patients who had disappointing clinical, gasometric, or polysomnographic outcomes of ventilation. The leak-detection procedures varied according to the type of ventilation and the supposed underlying pathophysiological mechanism. Significant leaks were detected in 132 patients (76%); therapeutic changes were then prescribed to optimize outcomes. We present a practical method to apply in patients with suboptimal ventilation outcomes. If leaks can be detected during treatment, the probable cause of treatment failure can sometimes be established and possible pathophysiological mechanisms better understood. With this knowledge, it may be possible to improve ventilation.

  1. 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.

  2. 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.

  3. 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.

  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 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.

  6. 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

  7. 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.

  8. 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.

  9. Microbial health risks associated with exposure to stormwater in a water plaza.

    PubMed

    Sales-Ortells, Helena; Medema, Gertjan

    2015-05-01

    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 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 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. Campylobacter, Cryptosporidium and Legionella pneumophila were the pathogens investigated. Microbial source tracking tools were used to determine the origin (human, animal) of the intestinal pathogens. Cryptosporidium was not found in any sample. Campylobacter was found in all samples, with higher concentrations in samples containing human Bacteroides than in samples with zoonotic contamination (15 vs 3.7 gc (genomic copies)/100 mL). In both cases, the estimated disease risk associated with Campylobacter and recreational exposure was higher than the Dutch national incidence. This indicates that the health risk associated with recreational exposure to the water plaza is significant. L. pneumophila was found only in two out of ten pond samples. Legionnaire's disease risks were lower than the Dutch national incidence. Presence of human Bacteroides indicates possible cross-connections with the CSS that should be identified and removed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. 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.

  11. Aerodynamic consequences of a pneumotachograph mask leak

    NASA Astrophysics Data System (ADS)

    May, Nicholas A.

    Studies in airflow during speech production typically use a pneumotachographic mask system placed upon the face to measure the expired airflows. Accurate measures of airflow require mask calibration and a complete seal of the mask rim to the face. Literature frequently cites mask rim leaks as causing flow measure inaccuracies, but quantitative studies of inaccuracies are needed. The purpose of this study was to determine the degree of inaccuracy of flow measurement using a Glottal Enterprises aerodynamic system for a variety of leak sizes. The primary hypothesis was that the greater the air leak cross sectional area at the rim of the mask, the greater the reduction in measured flows through the mask (and therefore the greater the error in measuring the upstream airflow). A range of airflows was both pushed and pulled through the Glottal Enterprises mask system with leaks being simulated by metal tubes of various cross-sectional areas. Two leak locations (bridge-of-nose and corner-of-mouth), single vs. multiple leaks, and two different leak geometries (rectangular and elliptical) were studied. Results suggest the following conclusions: (1) As leak area increases, the amount of leak flow increases; (2) the amount of flow leak is not independent of location; (3) given equivalent leak area, multiple leak locations provide more airflow resistance and less leak flow; (4) elliptical tubes were found to be more resistive to airflow than rectangular tubes. A general equation was obtained that relates the amount of flow reduction (the leak flow) to the rim leak cross sectional area and the upstream flow: Leak(cc/s) = 0.4125*Area(cm2)*Flow(cc/s), for airway flow in the range of +/-2000 cc/s. This equation may provide researchers and clinicians in the field with a tool for generalizing airflow leak effects.

  12. 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...

  13. 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...

  14. 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.

  15. 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...

  16. 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.

  17. 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.

  18. 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.

  19. 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...

  20. 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.

  1. 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

  2. Detecting Leaks With An Infrared Camera

    NASA Technical Reports Server (NTRS)

    Easter, Barry P.; Steffins, Alfred P., Jr.

    1994-01-01

    Proposed test reveals small leak in gas pipe - for example, leak through fatigue crack induced by vibration - even though insulation covers pipe. Infrared-sensitive video camera aimed at part(s) containing suspected leak(s). Insulated pipe pressurized with gas that absorbs infrared light. If crack were present, escaping gas travels along outside of pipe until it reached edge of insulation. Gas emerging from edge of insulation appears as dark cloud in video image.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. Leaking electricity in domestic appliances

    SciTech Connect

    Meier, Alan; Rosen, Karen

    1999-05-01

    Many types of home electronic equipment draw electric power when switched off or not performing their principal functions. Standby power use (or ''leaking electricity'') for most appliances ranges from 1 - 20 watts. Even though standby use of each device is small, the combined standby power use of all appliances in a home can easily exceed 50 watts. Leaking electricity is already responsible for 5 to 10 percent of residential electricity use in the United States and over 10 percent in Japan. An increasing number of white goods also have standby power requirements. There is a growing international effort to limit standby power to around one watt per device. New and existing technologies are available to meet this target at little or no extra cost.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. In focus. Life after BioethicsLine: a reply to Joyce Plaza.

    PubMed

    Cody, Dean E

    2002-01-01

    The recent closure and removal of BioethicsLine led many researchers to wonder where to turn for their research needs. Joyce Plaza wrote that the closure is a mistake. In this essay I maintain, contra Plaza, that due to its cross-disciplinary nature researchers can find bioethics literature in other databases. In developing the search strategy the researcher needs to consider what the problem is about. If the researcher has a philosophical approach in mind, a wise choice would be to use Philosopher's Index; a legal approach suggests using Academic Universe, Westlaw, Lexis or legal databases freely available through state and federal websites. Further, in so far as the National Library of Medicine is integrating citations in BioethicsLine into the NLM Gateway databases (PubMed and LOCATORplus) I point out suggestions on using the latter databases effectively. There is a wealth of information readily available and researchers have much to learn by trying the alternatives.

  13. [The characteristics of nuclear families in two study areas: Plaza de la Revolucion and Yateras].

    PubMed

    Catasus Cervera, S I

    1984-01-01

    Differences in family characteristics in two regions of Cuba are analyzed. Data are from a recent survey that covered 1,107 nuclear families in the municipality of Plaza de la Revolucion and 671 in the municipality of Yateras, involving about 4,000 individuals in each case. Consideration is given to family composition and characteristics of head of household. The emphasis is on differences in family characteristics in rural and urban areas. (summary in ENG, FRE)

  14. 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

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

    PubMed

    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. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  16. [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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Metallurgical Analysis of Leaking Tray Packs

    DTIC Science & Technology

    1990-05-01

    i j L Copyi MTL TR 90-30 JAD AD-A223 157 METALLURGICAL ANALYSIS OF LEAKING TRAY PACKS KUAN S. LEI GEO-CENTERS, INC. NEWTON, MA FRANK C. CHANG and...RECIPIENTS CATALOG NUMBER 4. TITLE (and Subute) 5. TYPE OF REPORT & PERIOD COVERED Final Report METALLURGICAL ANALYSIS OF LEAKING TRAY PACKS 6...CLASSIFICATION OF THIS PAGE (Wihn Daa Entend) Block No. 20 ABSTRACT A metallurgical analysis was performed to determine the cause of leaking tray packs and the

  2. Ion pump and leak life test

    NASA Technical Reports Server (NTRS)

    Ierokomos, N.

    1972-01-01

    The fabrication and long term testing of a flight type ion pump and sintered inlet leak are described. These tests were conducted over a period of one year at an ion pump pressure of approximately 0.000001 torr. These long term tests were conducted to investigate aging of ion pumps and leaks under continuous use. Pumping speed and leak conductance, as well as other parameters, were measured on a weekly basis with ion pump start tests conducted on a monthly basis.

  3. 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.

  4. 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.

  5. Leak testing -- Is personnel certification necessary?

    SciTech Connect

    Elder, G.R.

    1995-12-31

    The amount of leak testing being done far exceeds any other NDT method and probably the sum of all the other NDT methods. There are twelve leak test methods, thirty three major leak test techniques, numerous tracer fluids and hundreds of leak detectors. For many companies their manufacturing processes or products themselves require some degree of leak tightness to function or to maintain their product integrity. Then when should a company make leak testing a NDT method and qualify test personnel? Some considerations are: (1) type of LT methods and techniques (operator dependent); (2) the regulatory requirements; (3) the amount of risk the company can afford; (4) the environmental impact of a leak; (5) the design specifications; (6) customer expectations and requirements; (7) visibility of the product and impact on credibility; and (8) the costs to implement a certification program. For many companies, the final consideration of cost is the primary reason for not certifying leak test personnel. These costs are partially and in some cases are completely offset by the savings derived from: (1) more reliable, consistent test results where fewer leaks are missed and warranty cost are reduced; (2) reduced test time; (3) higher test personnel proficiency is maintained; and (4) less equipment maintenance cost. Those companies that use automatic production process don`t have an operator to certify, but other companies need to evaluate the advantages vs the cost to implement an NDT LT personnel certification program. Many companies may find the cost very reasonable.

  6. 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.

  7. [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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. Leak checker data logging system

    SciTech Connect

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

    1994-12-31

    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.

  14. 40 CFR 63.1005 - Leak repair.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., tightening the packing gland nuts and/or ensuring that the seal flush is operating at design pressure and... liquid service. The leak identification on a valve in gas/vapor or light liquid service may be removed... monitoring. The leak identification on a connector in gas/vapor or light liquid service may be removed after...

  15. 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.

  16. Fighting the Epidemic of Nuclear Plant Leaks.

    ERIC Educational Resources Information Center

    Udell, Richard A.

    1983-01-01

    The current epidemic of steam generator tube leaks alone should put to rest the rosy future once envisioned for nuclear power. It is impossible to regulate quality into a nuclear plant; it must be built and designed that way. The economic impact of the leaks is discussed. (RM)

  17. 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

  18. 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.

  19. 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.

  20. 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

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

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At the grand opening of the newly expanded KSC Visitor Complex, Center Director Roy Bridges addresses guests and the media. The $13 million addition to the Visitor Complex includes an International Space Station-themed ticket plaza, featuring a structure of overhanging solar panels and astronauts performing assembly tasks, a new information center, films, and exhibits. 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.

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

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The $13 million expansion to KSC's Visitor Complex includes a new International Space Station-themed ticket plaza, featuring a structure of overhanging solar panels and astronauts performing assembly tasks. Other additions are the new information center, a walk-through Robot Scouts exhibit, a wildlife exhibit, and the film Quest for Life in a new 300-seat theater. 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.

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

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The $13 million expansion to KSC's Visitor Complex includes a new International Space Station-themed ticket plaza, featuring a structure of overhanging solar panels and astronauts performing assembly tasks. Other additions are a new information center, a walk-through Robot Scouts exhibit, a wildlife exhibit, and the film Quest for Life in a new 300-seat theater. 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.

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

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The KSC Visitor Complex welcomes more than 2.75 million visitors each year. Featured are bus tours of the space center with up- close views of Space Shuttle launch facilities and International Space Station processing. The Visitor Complex has recently undergone a $13 million expansion, with new exhibits, films, 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.

  5. 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.

  6. High-sensitivity photoacoustic leak testing.

    PubMed

    Huang, Eric; Dowling, David R; Whelan, Timothy; Spiesberger, John L

    2003-10-01

    The photoacoustic effect may be exploited for the detection and localization of gas leaks from otherwise sealed components. The technique involves filling the test component with a tracer gas, and radiating the component to produce photoacoustic sound from any leak site where tracer gas is present. This paper describes demonstration experiments utilizing 10.6-micro radiation from a carbon-dioxide laser and sulfur hexafluoride as a tracer gas for photoacoustic leak testing at leak rates between 6 x 10(-5) cm3/s (1 cm3 in 4.6 h) and 5 x 10(-9) cm3/s (1 cm3 in 6.3 years). The technique may reach or exceed the capabilities of the most sensitive commercial leak test systems using helium mass-spectrometers. In addition, comparison of the measured results to a simple scaling law suggests that tracer gas cloud geometry influences the photoacoustic signal amplitude.

  7. 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.

  8. 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

  9. 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

  10. Dissecting Plant Genomes with the PLAZA Comparative Genomics Platform1[W

    PubMed Central

    Van Bel, Michiel; Proost, Sebastian; Wischnitzki, Elisabeth; Movahedi, Sara; Scheerlinck, Christopher; Van de Peer, Yves; Vandepoele, Klaas

    2012-01-01

    With the arrival of low-cost, next-generation sequencing, a multitude of new plant genomes are being publicly released, providing unseen opportunities and challenges for comparative genomics studies. Here, we present PLAZA 2.5, a user-friendly online research environment to explore genomic information from different plants. This new release features updates to previous genome annotations and a substantial number of newly available plant genomes as well as various new interactive tools and visualizations. Currently, PLAZA hosts 25 organisms covering a broad taxonomic range, including 13 eudicots, five monocots, one lycopod, one moss, and five algae. The available data consist of structural and functional gene annotations, homologous gene families, multiple sequence alignments, phylogenetic trees, and colinear regions within and between species. A new Integrative Orthology Viewer, combining information from different orthology prediction methodologies, was developed to efficiently investigate complex orthology relationships. Cross-species expression analysis revealed that the integration of complementary data types extended the scope of complex orthology relationships, especially between more distantly related species. Finally, based on phylogenetic profiling, we propose a set of core gene families within the green plant lineage that will be instrumental to assess the gene space of draft or newly sequenced plant genomes during the assembly or annotation phase. PMID:22198273

  11. 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.

  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. Fresh leaks plague Hanford Nuclear Reservation

    NASA Astrophysics Data System (ADS)

    Gwynne, Peter

    2013-04-01

    Up to six tanks holding radioactive material at the Hanford Nuclear Reservation in Richland, Washington, were thought to be leaking last month as employees at the site began to evaluate 14 further tanks that also appeared to have lost liquid.

  15. 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.

  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. 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.

  18. 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

  19. 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.

  20. Reliable method for testing gross leaks in semiconductor component packages

    NASA Technical Reports Server (NTRS)

    Altshuler, T. L.

    1968-01-01

    Simple, reliable, inexpensive method for gross-leak testing has been devised, based upon the conventional fine-leak technique. The sensitivity ranges from the detection of very large leaks down to leaks of 10 to the minus seven cc helium per sec.

  1. 40 CFR 1065.345 - Vacuum-side leak verification.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... a leak. (e) Vacuum-decay leak test. To perform this test you must apply a vacuum to the vacuum-side volume of your sampling system and then observe the leak rate of your system as a decay in the applied... specifications of subpart C of this part and of this subpart D. Perform a vacuum-decay leak test as follows: (1...

  2. 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.

  3. 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.

  4. 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.

  5. 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.

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

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At the grand opening of the newly expanded KSC Visitor Complex, Center Director Roy Bridges presents Deep Space Nine star Avery Brooks with a plaque, NASA jacket and hat. Brooks narrates the new film Quest for Life at the Visitor Center. Brooks was recognized for his contribution to advancing the public's understanding of NASA and the search for life elsewhere in the universe. The Complex now includes an International Space Station-themed ticket plaza, featuring a structure of overhanging solar panels and astronauts performing assembly tasks, a new foyer, films, and exhibits. 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.

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

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At the grand opening of the newly expanded KSC Visitor Complex, Center Director Roy Bridges presents Deep Space Nine star Avery Brooks with a plaque, recognizing his contribution to advancing the public's understanding of NASA and the search for life elsewhere in the universe. Brooks narrates the new film Quest for Life at the Visitor Center. The $ 13 million addition to the Visitor Complex now includes an International Space Station- themed ticket plaza, featuring a structure of overhanging solar panels and astronauts performing assembly tasks, a new information center, films, and exhibits. 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.

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

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The newly added Robot Scouts exhibit at the KSC Visitor Complex is situated next to the Rocket Garden. Part of the $13 million expansion to the Visitor Complex, the exhibit helps describe for visitors the accomplishments of unsung space heroes - space probes - and their role in space exploration. It also includes a display of how data from robotic probes might be used to build a human habitat for Mars. Visitors can witness a simulated Martian sunset. Other additions include a new foyer, films, 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.

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

    NASA Technical Reports Server (NTRS)

    1999-01-01

    A host robot, Starquester 2000, helps describe for visitors the accomplishments of unsung space heroes - space probes - and their role in space exploration. The walk-through Robot Scouts exhibit is part of the $13 million expansion to KSC's Visitor Complex. 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. Inaugurated three decades ago, the Visitor Complex 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 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.

  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 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.

  12. 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 Robot Scouts exhibit in the $13 million expansion to KSC's Visitor Complex, this display offers a view of how data from robotic probes might be used to build a human habitat for Mars. Visitors witness a simulated Martian sunset. Other new additions include and information center, 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.

  13. 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.

  14. 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

  15. 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

  16. Detecting Conductive Liquid Leaking from Nonconductive Pipe

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C.

    2003-01-01

    A method that can be implemented with relatively simple electronic circuitry provides a capability for detecting leakage of an electrically conductive liquid from an electrically nonconductive underground pipe. Alternatively or in addition, the method can be applied to locate the pipe, whether or not there is a leak. Although the method is subject to limitations (some of which are described below), it is still attractive as an additional option for detecting leaks and locating pipes without need for extensive digging. The method is based on capacitive coupling of an alternating electrical signal from the liquid to a portable electronic unit that resembles a metal detector. A signal voltage is applied to the liquid at some convenient point along the pipe: for example, the signal could be coupled into the liquid via an aboveground metal pipe fitting, the interior surface of which is in contact with the liquid. The signal is conducted through the liquid in the pipe; in the case of diffusive leak of liquid into the surrounding ground, the signal is conducted through the leak, into the portion of the adjacent ground that has become soaked with the liquid. (A drip leak cannot be detected by this method because there is no conductive path between the liquid inside and the liquid outside the pipe.) The portable unit includes an electrically conductive plate connected to the input terminal of an amplifier. When the plate is brought near the pipe or the leaked liquid, a small portion of the signal power is coupled capacitively from the liquid to the plate. The user scans the plate near the ground surface to find the locus of maximum signal strength. The leak can be identified as a relatively wide area, contiguous with the location of the pipe, over which the signal is detectable.

  17. 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

  18. 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

  19. Leak and Pipe Detection Method and System

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C. (Inventor)

    2003-01-01

    A method and system for locating leaks of conductive fluids from non-conductive pipes and other structures or for locat- ing non-conductive pipes or structures having conductive fluid contained therein, employ a charge generator to apply a time varying charge to the conductive fluid, and a capaci- tive type detector that can detect the variable charge that is induced in the fluid. The capacitive detector, which prefer- ably includes a handheld housing, employs a large conduc- tive pickup plate that is used to locate the pipe or leak by scanning the plate over the ground and detecting the induced charge that is generated when the plate comes in close proximity to the pipe or leak. If a leak is encountered, the resulting signal will appear over an area larger than expected for a buried pipe, assuming the leak provides an electrically conductive path between the flow and the wet surrounding ground. The detector uses any suitable type of indicator device, such as a pair of headphones that enable an operator to hear the detected signal as a chirping sound, for example.

  20. 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.

  1. Escape dynamics through a continuously growing leak

    NASA Astrophysics Data System (ADS)

    Kovács, Tamás; Vanyó, József

    2017-06-01

    We formulate a model that describes the escape dynamics in a leaky chaotic system in which the size of the leak depends on the number of the in-falling particles. The basic motivation of this work is the astrophysical process, which describes the planetary accretion. In order to study the dynamics generally, the standard map is investigated in two cases when the dynamics is fully hyperbolic and in the presence of Kolmogorov-Arnold-Moser islands. In addition to the numerical calculations, an analytic solution to the temporal behavior of the model is also derived. We show that in the early phase of the leak expansion, as long as there are enough particles in the system, the number of survivors deviates from the well-known exponential decay. Furthermore, the analytic solution returns the classical result in the limiting case when the number of particles does not affect the leak size.

  2. 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.

  3. 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

  4. Rotating leaks in the stadium billiard

    NASA Astrophysics Data System (ADS)

    Appelbe, B.

    2016-11-01

    The open stadium billiard has a survival probability, P(t), that depends on the rate of escape of particles through the leak. It is known that the decay of P(t) is exponential early in time while for long times the decay follows a power law. In this work, we investigate an open stadium billiard in which the leak is free to rotate around the boundary of the stadium at a constant velocity, ω. It is found that P(t) is very sensitive to ω. For certain ω values P(t) is purely exponential while for other values the power law behaviour at long times persists. We identify three ranges of ω values corresponding to three different responses of P(t). It is shown that these variations in P(t) are due to the interaction of the moving leak with Marginally Unstable Periodic Orbits (MUPOs).

  5. Rotating leaks in the stadium billiard.

    PubMed

    Appelbe, B

    2016-11-01

    The open stadium billiard has a survival probability, P(t), that depends on the rate of escape of particles through the leak. It is known that the decay of P(t) is exponential early in time while for long times the decay follows a power law. In this work, we investigate an open stadium billiard in which the leak is free to rotate around the boundary of the stadium at a constant velocity, ω. It is found that P(t) is very sensitive to ω. For certain ω values P(t) is purely exponential while for other values the power law behaviour at long times persists. We identify three ranges of ω values corresponding to three different responses of P(t). It is shown that these variations in P(t) are due to the interaction of the moving leak with Marginally Unstable Periodic Orbits (MUPOs).

  6. Scanning, standoff TDLAS leak imaging and quantification

    NASA Astrophysics Data System (ADS)

    Wainner, Richard T.; Aubut, Nicholas F.; Laderer, Matthew C.; Frish, Michael B.

    2017-05-01

    This paper reports a novel quantitative gas plume imaging tool, based on active near-infrared Backscatter Tunable Diode Laser Absorption Spectroscopy (b-TDLAS) technology, designed for upstream natural gas leak applications. The new tool integrates low-cost laser sensors with video cameras to create a highly sensitive gas plume imager that also quantifies emission rate, all in a lightweight handheld ergonomic package. It is intended to serve as a lower-cost, higherperformance, enhanced functionality replacement for traditional passive non-quantitative mid-infrared Optical Gas Imagers (OGI) which are utilized by industry to comply with natural gas infrastructure Leak Detection and Repair (LDAR) requirements. It addresses the need for reliable, robust, low-cost sensors to detect and image methane leaks, and to quantify leak emission rates, focusing on inspections of upstream oil and gas operations, such as well pads, compressors, and gas plants. It provides: 1) Colorized quantified images of path-integrated methane concentration. The images depict methane plumes (otherwise invisible to the eye) actively interrogated by the laser beam overlaid on a visible camera image of the background. The detection sensitivity exceeds passive OGI, thus simplifying the manual task of leak detection and location; and 2) Data and algorithms for using the quantitative information gathered by the active detection technique to deduce plume flux (i.e. methane emission rate). This key capability will enable operators to prioritize leak repairs and thereby minimize the value of lost product, as well as to quantify and minimize greenhouse gas emissions, using a tool that meets EPA LDAR imaging equipment requirements.

  7. 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

  8. 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).

  9. 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.

  10. 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.

  11. Diagnosis of anastomotic leak: electrolyte detection versus barium fluoroscopy.

    PubMed

    DeArmond, Daniel T; Carswell, Aimee; Louden, Christopher L; Simmons, Jeremy D; Bayer, Johanna; Das, Nitin A; Johnson, Scott B

    2013-06-15

    We recently described a new method of diagnosing anastomotic leak using the detection of electrical changes induced by electrolyte extravasation from a surgically created gastric leak site in experimental rats. We sought to compare the sensitivity and specificity of anastomotic leak detection for this method to that of upper gastrointestinal (GI) barium fluoroscopy. Experimental rats with a surgically created gastric leak site and controls were interrogated as to the presence of leak using either the electrolyte-gated leak detection method or upper GI barium fluoroscopy. The sensitivity and specificity of leak detection for the two methods were compared. The sensitivity and specificity of electrolyte-gated leak detection were both 100% (95% confidence interval 69-100%). Barium upper GI fluoroscopy misidentified one leak as a control and one control as a leak, for a sensitivity and specificity of 80% each (95% confidence interval 37-97%). No statistically significant difference was seen between electrolyte-gated leak detection and barium upper GI fluoroscopy in terms of the sensitivity and specificity of anastomotic leak detection. Electrolyte-gated leak detection was similarly sensitive and specific for anastomotic leak detection as upper GI barium fluoroscopy, the current standard. The electrolyte-gated method has the advantages of an inert contrast agent (normal saline) and the possibility of performing leak interrogation at the bedside. Electrolyte-gated leak detection might represent a plausible alternative to upper GI barium fluoroscopy for routine postoperative anastomotic leak surveillance after esophagectomy or other foregut surgery. Copyright © 2013 Elsevier Inc. All rights reserved.

  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. Copyright © 2013 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.

  13. 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...

  14. 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.

  15. 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...

  16. A new device for paravalvular leak closure

    PubMed Central

    Ercan, Ertugrul; Tengiz, Istemihan; Turk, Ugur; Ozyurtlu, Ferhat; Alioglu, Emin

    2015-01-01

    Percutaneous closure of a prosthetic paravalvular leak (PVL) is a challenging procedure. Operators must use devices constructed for other applications. We present the use of a device which is specifically designed for PVL closure. To the best of our knowledge, there is no publication in MEDLINE reporting the use of the device. PMID:25870623

  17. EPA Encourages Americans to Become Leak Detectives

    EPA Pesticide Factsheets

    PHILADELPHIA ( March 11, 2016) Each year, more than one trillion gallons of water are wasted by easy-to-fix household leaks, according to the U.S. Environmental Protection Agency's (EPA's) WaterSense program. That's why EPA is encouraging consumers t

  18. 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.

  19. 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.

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 10 CFR 36.59 - Detection of leaking sources.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... leakage at intervals not to exceed 6 months using a leak test kit or method approved by the Commission or... contamination in the pool if specifically provided for in written emergency procedures. (c) If a leaking...

  6. 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.

  7. 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 of...

  8. 49 CFR 230.64 - Leaks under lagging.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., 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 of...

  9. Study of Residual Gas Analyser (RGA) Response towards Known Leaks

    NASA Astrophysics Data System (ADS)

    Pathan, Firozkhan S.; Khan, Ziauddin; Semwal, Pratibha; George, Siju; Raval, Dilip C.; Thankey, Prashant L.; Manthena, Himabindu; Yuvakiran, Paravastu; Dhanani, Kalpesh R.

    2012-11-01

    Helium leak testing is the most versatile form of weld qualification test for any vacuum application. Almost every ultra-high vacuum (UHV) system utilizes this technique for insuring leak tightness for the weld joints as well as demountable joints. During UHV system under operational condition with many other integrated components, in-situ developed leaks identification becomes one of the prime aspect for maintaining the health of such system and for continuing the experiments onwards. Since online utilization of leak detector (LD) has many practical limitations, residual gas analyser (RGA) can be used as a potential instrument for online leak detection. For this purpose, a co-relation for a given leak rate between Leak Detector and RGA is experimentally established. This paper describes the experimental aspect and the relationship between leak detector and RGA.

  10. Indoor air quality study in Agency Building Two, Empire State Plaza, Albany, New York

    SciTech Connect

    Not Available

    1992-04-01

    The quality of the indoor environment and potential health conquences have become major concerns for occupants of office buildings. Increasing ventilation rates are often recommended as a potential solution for indoor air quality (IAQ) problems, whether real or perceived as real by occupants. To date, limited quantitative data have been collected to relate increased outdoor-air intake to commonly measured IAQ or comfort parameters. The purpose of this study, conducted by GEOMET Technologies, Inc. for the New York State Energy Research and Development Authority, was to quantitatively assess the effect of ventilation rate on indoor air quality and associated parameters in an occupied office building, and occupant perceptions of air quality and comfort in the building. The building studied, a 20-story office tower located at the Empire State Plaza in Albany, New York, has a total floor area of approximately 100,000 ft. The building is operated by the New York State Office of General Services (OGS). The air-distribution component of the heating, ventilating, and air-conditioning (HVAC) system for the building consists of two air-handling units that serve the perimeter of the building through induction supply-air units and two other units that serve the core area of the building through ceiling diffusers. The perimeter system has separate zones that serve the north and south sides of the building, and the core system is zoned to individually serve the upper and lower halves of the building.

  11. Indoor air quality study in Agency Building Two, Empire State Plaza, Albany, New York. Final report

    SciTech Connect

    Not Available

    1992-04-01

    The quality of the indoor environment and potential health conquences have become major concerns for occupants of office buildings. Increasing ventilation rates are often recommended as a potential solution for indoor air quality (IAQ) problems, whether real or perceived as real by occupants. To date, limited quantitative data have been collected to relate increased outdoor-air intake to commonly measured IAQ or comfort parameters. The purpose of this study, conducted by GEOMET Technologies, Inc. for the New York State Energy Research and Development Authority, was to quantitatively assess the effect of ventilation rate on indoor air quality and associated parameters in an occupied office building, and occupant perceptions of air quality and comfort in the building. The building studied, a 20-story office tower located at the Empire State Plaza in Albany, New York, has a total floor area of approximately 100,000 ft. The building is operated by the New York State Office of General Services (OGS). The air-distribution component of the heating, ventilating, and air-conditioning (HVAC) system for the building consists of two air-handling units that serve the perimeter of the building through induction supply-air units and two other units that serve the core area of the building through ceiling diffusers. The perimeter system has separate zones that serve the north and south sides of the building, and the core system is zoned to individually serve the upper and lower halves of the building.

  12. 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.

  13. 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.

  14. Conceptual apparatus for detecting leaks of nonconductive liquids

    NASA Technical Reports Server (NTRS)

    Walsh, G. D.

    1968-01-01

    Apparatus detects leaks at joints in lines carrying electrically nonconductive liquids. The proposed apparatus could include a panel that would give a visual or audible indication of a leak /to permit manual shutdown/ and/or an electromechanical actuator that would automatically cut off the flow when a leak occurs.

  15. 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 single...

  16. 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 CPM...

  17. 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 single...

  18. 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 CPM...

  19. 49 CFR 195.134 - CPM leak detection.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 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 CPM...

  20. 49 CFR 195.444 - CPM leak detection.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 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 single...

  1. 49 CFR 195.134 - CPM leak detection.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 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 CPM...

  2. 49 CFR 195.444 - CPM leak detection.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 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 single...

  3. 49 CFR 195.134 - CPM leak detection.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 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 CPM...

  4. 49 CFR 195.444 - CPM leak detection.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 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 single...

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Fluid pipeline leak detection and location with miniature RF tags

    DOEpatents

    McIntyre, Timothy J.

    2017-05-16

    Sensors locate troublesome leaks in pipes or conduits that carry a flowing medium. These sensors, through tailored physical and geometric properties, preferentially seek conduit leaks or breaches due to flow streaming. The sensors can be queried via transceivers outside the conduit or located and interrogated inside by submersible unmanned vehicle to identify and characterize the nature of a leak. The sensors can be functionalized with other capabilities for additional leak and pipeline characterization if needed. Sensors can be recovered from a conduit flow stream and reused for future leak detection activities.

  11. 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.

  12. Method for mapping a natural gas leak

    DOEpatents

    Reichardt, Thomas A [Livermore, CA; Luong, Amy Khai [Dublin, CA; Kulp, Thomas J [Livermore, CA; Devdas, Sanjay [Albany, CA

    2009-02-03

    A system is described that is suitable for use in determining the location of leaks of gases having a background concentration. The system is a point-wise backscatter absorption gas measurement system that measures absorption and distance to each point of an image. The absorption measurement provides an indication of the total amount of a gas of interest, and the distance provides an estimate of the background concentration of gas. The distance is measured from the time-of-flight of laser pulse that is generated along with the absorption measurement light. The measurements are formatted into an image of the presence of gas in excess of the background. Alternatively, an image of the scene is superimposed on the image of the gas to aid in locating leaks. By further modeling excess gas as a plume having a known concentration profile, the present system provides an estimate of the maximum concentration of the gas of interest.

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. Mollaret's meningitis associated with cerebrospinal fluid leak.

    PubMed

    Plit, M L; Miller, G B; Berkowitz, F E; Gear, J H

    1982-10-23

    Mollaret's meningitis or the benign recurrent meningitis syndrome is a rare disorder not previously described in Africa. The syndrome has a characteristic clinical presentation with spinal fluid pleocytosis, often with unusual 'epithelial' cells. With contemporary techniques no causative organism has been incriminated. The aetiology remains speculative, but we report on a patient found to have a cerebrospinal fluid leak, which may represent a factor in the pathogenesis of this disorder.

  18. 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.

  19. [A new leak test of anesthetic machine].

    PubMed

    Kitagawa, H; Tanaka, M; Hirata, A; Hirata, K; Sai, Y; Nosaka, S; Amakata, Y; Oku, S

    1993-09-01

    A case of the inspired PCO2 increase secondary to the malfunction of expiratory valve due to a defected edge of creator is presented. In this case, we could not detect the malfunction of expiratory valve using the preanesthetic routine leak test but found it by observing the expiratory phase of the capnometric curve. Therefore, we devised a new leak test for checking the malfunction of inspiratory and expiratory valves. This test is simple and effective. The test consists of the following procedures.: 1. Connecting yokes to the oxygen piping system. 2. Connecting the breathing bag. 3. Occluding the inspiratory terminal. Closing the semiclosed valve completely. 4. Flushing the O2 gas and increasing the pressure of breathing circuit to 30 cmH2O. 5. Monitoring the pressure gauge of the anesthesia system. If the function of valves is normal, the system pressure decreases slowly. If either of the valves works wrong, it decreases rapidly. We checked anesthesia machines in our facilities using the new leak test, and found some cases of the expiratory valve malfunctions.

  20. Imaging spectrometer for fugitive gas leak detection

    NASA Astrophysics Data System (ADS)

    Hinnrichs, Michele

    1999-12-01

    Under contract to the U.S. Air Force and Navy, Pacific Advanced Technology has developed a very sensitive infrared imaging spectrometer that can perform remote imaging and spectro-radiometry. One of the most exciting applications for this technology is in the remote monitoring of smoke stack emissions and fugitive leaks. To date remote continuous emission monitoring (CEM) systems have not been approved by the EPA, however, they are under consideration. If the remote sensing technology is available with the sensitivity to monitor emission at the required levels and man portable it can reduce the cost and improve the reliability of performing such measurements. Pacific Advanced Technology (PAT) believes that it currently has this technology available to industry. This paper will present results from a field test where gas vapors during a refueling process were imaged and identified. In addition images of propane from a leaking stove will be presented. We at PAT have developed a real time image processing board that enhances the signal to noise ratio of low contrast gases and makes them easily viewable using the Image Multispectral Sensing (IMSS) imaging spectrometer. The IMSS imaging spectrometer is the size of a camcorder. Currently the data is stored in a Notebook computer thus allowing the system to be easily carried into power plants to look for fugitive leaks. In the future the IMSS will have an embedded processor and DSP and will be able to transfer data over an Ethernet link.

  1. Color Changing Material for Hydrogen Leak Detection

    NASA Technical Reports Server (NTRS)

    Victor, Megan E.

    2014-01-01

    Kennedy Space Center scientists developed a hydrogen leak sensor utilizing a combination of chemochromic pigment and polymer that can be molded or fiber spun into rigid or flexible shapes such as tape. The sensor turns a dark color when exposed to hydrogen gas. This sensor has proven to be very effective for pinpointing the exact location of leaks in hydrogen gas lines and fittings at launch pads. Kennedy Space Center exclusively licensed this technology to the University of Central Florida (UCF), who also holds patents that are complimentary to KSC's. UCF has bundled the patents and exclusively licensed the portfolio to HySense Technology LLC, a startup company founded by a UCF professor who supports the UCF Florida Solar Energy Center (FSEC). HySense has fully developed its product (known as Intellipigment"TM"), and currently has five commercial customers. The company recently won the $100,000 first-place award at the CAT5 innovation competition at the Innovation Concourse of the Southeast: Safety & Manufacturing event in Orlando, FL. Commercial production and sales of this technology by HySense Technology will make this leak sensor widely available for use by NASA, DoD, and industries that utilize hydrogen gas.

  2. [Capillary leak syndrome disclosing Ofuji's papuloerythroderma].

    PubMed

    Carsuzaa, F; Pierre, C; Morand, J J; Farnarier, C; Marrot, F; Kaplanski, G

    1996-01-01

    Capillary leak syndrome is a specific entity among syndromes with capillary hyperpermeability. Endothelial cell activation is related to the higt level of adhesion molecules (sICAM-1, sVCAM-&, sCD62E) possibly due to several cytokines (IL-2, TNF ...). An 84-year-old woman was hospitalized for erythroderma. Ofujui papuloerythroderma was diagnosed and edema was attributed to capillary leak. A kinetic study of several cytokines and adhesion molecules sCD62E, sVCAM-1 and sICAM-1 was done. Outcome was favorable with corticopuvatherapy. The capillary leak syndrome reported here is simlar to that described in other erythrodermas with or without lymphoma. The keratinocyte would be activated by the CD4 T lymphocyte via the gamma-interferon mediator. The T cell secretes cytokines (interleukin-1, tumor necrosis factor ...) which activates the endothelium and increases vascular permeability. The level of adhesion molecules and changes observed during the episode of edema demonstrated the endothelial activation.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. [Risk of low birth weight in the Plaza de la Habana region].

    PubMed

    Stüsser, R; Paz, G; Ortega, M; Pineda, S; Infante, O; Martín, P; Ordóñez, C

    1993-03-01

    The objective of this study was to confirm the risk factors (RF) for low birth-weight (LBW) and suggest new risk factors, which were analyzed separately and together, in order to define a program to be coordinated by family doctors to reduce the frequency of this problem. For this purpose, a retrospective cross-sectional survey was carried out with 57 cases (mothers who had had LBW babies) and 58 controls (mothers who had not had LBW babies). In addition, data were obtained from the prenatal records of mothers who received care at family doctors' offices and at the clinica in the Plaza de la Habana Area. Estimates were made of the relative risk and the percentage attributable risk of 107 hypothetical RF for LBW from a clinical-epidemiological and social standpoint. One-way analysis of variance, the chi-square test, multiple linear regression, and logistic regression were used to analyze the results, which suggested the following RF for LBW: family dysfunction, family crisis, lack of spousal support, extended family, failure to attend prenatal group sessions for pregnant women, and failure to receive education on how to prevent LBW. The multifactorial risk profile was the following: risk of [corrected] intrauterine growth retardation, family dysfunction, threat of preterm delivery, coffee-drinking, attendance at fewer than 11 prenatal checkups, and failure to attend prenatal group sessions for pregnant women. The variables excluded from the model were: low weight-for-height, lack of spousal support, smoking more than 10 cigarettes a day, and family history of LBW. The findings confirmed 10 of the suspected risk factors for LBW in Cuba and nine of those described in the international literature. Maternal age, spontaneous abortion, and alcohol consumption were not confirmed. Six RF for LBW preventable by the family doctor through his/her actions at the family and community level are identified, as is a multifactorial profile of six RF for LBW. On the basis of these

  8. 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.

  9. 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.

  10. Scintigraphy for Pulmonary Capillary Protein Leak

    DTIC Science & Technology

    1982-09-01

    lnate? o~~d) - aREPORT DOCUMENTATION PAGE UFFiEI.N C011l’Ll1TING FORM Anteuim Swvnuztl R porta IepoI Scintigraphy for Pulmonary Capillary Protein Leak...higher "slope of injury" (pɘ.01) following thoractomy, lung , retraction and lym..,ph duct cannulation. Further studies are required in animals...undergoing thoracotomyw only. This suggests that the acute sheep lung lymph model is associated with acute pulmonary injury and, therefore, will make

  11. Endoscopic stenting of gastric staple line leak following sleeve gastrectomy.

    PubMed

    Slim, Rita; Smayra, Tarek; Chakhtoura, Ghassan; Noun, Roger

    2013-11-01

    Laparoscopic sleeve gastrectomy is known to be associated with a risk of gastric staple line leak. We report on our experience with endoscopic stenting of the anomalous leaking tract. Three cases of post sleeve gastric leak confirmed by computed tomography scan were treated by endoscopic stenting of their leak with a plastic endoprosthesis under fluoroscopic and endoscopic guidance. Endoscopic stenting by means of biliary or pancreatic endoprosthesis was successful in the three patients. The median number of endoscopy procedures per patient was 1.3. Stents were extracted 6 to 10 weeks after their placement. Neither morbidity nor recurrence was noticed on follow-up. Endoscopic stenting of gastric staple line leak following sleeve gastrectomy proved to be an efficacious technique for leak healing.

  12. 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.

  13. 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.

  14. 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.

  15. [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.

  16. 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

  17. 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.

  18. Percutaneous closure of a prosthetic pulmonary paravalvular leak.

    PubMed

    Seery, Thomas J; Slack, Michael C

    2014-01-01

    Paravalvular leak following prosthetic valve surgery has the potential to cause serious complications such as hemolysis and congestive heart failure. Successful percutaneous closures of prosthetic mitral and aortic paravalvular leaks have been performed as an alternative to reoperation. This case represents the first known report of successful percutaneous closure of a prosthetic pulmonary paravalvular leak in an adult patient with a history of congenital heart disease using two muscular ventricular septal defect occluder devices. © 2013 Wiley Periodicals, Inc.

  19. Offsite radiological consequence analysis for the waste transfer leak

    SciTech Connect

    ZIMMERMAN, B.D.

    2003-03-21

    This document quantifies the offsite radiological/consequence of the bounding waste transfer leak accident for comparison with the 25 rem Evaluation Guideline established in DOE-STD-3009, Appendix A. The bounding waste transfer leak accident is a fine spray leak into the air. The calculation applies reasonably conservative input parameters in accordance with DOE-STD-3009, Appendix A, guidance. The calculated offsite dose of 0.7 rem does not challenge the Evaluation Guideline.

  20. 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.

  1. 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.

  2. 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.

  3. Drain amylase aids detection of anastomotic leak after esophagectomy

    PubMed Central

    Baker, Erin H.; Hill, Joshua S.; Reames, Mark K.; Symanowski, James; Hurley, Susie C.

    2016-01-01

    Background Anastomotic leak following esophagectomy is associated with significant morbidity and mortality. As hospital length of stay decreases, the timely diagnosis of leak becomes more important. We evaluated CT esophagram, white blood count (WBC), and drain amylase levels in the early detection of anastomotic leak. Methods The diagnostic performance of CT esophagram, drain amylase >800 IU/L, and WBC >12,000/µL within the first 10 days after surgery in predicting leak at any time after esophagectomy was calculated. Results Anastomotic leak occurred in 13 patients (13%). CT esophagram performed within 10 days of surgery diagnosed six of these leaks with a sensitivity of 0.54. Elevation in drain amylase level within 10 days of surgery diagnosed anastomotic leak with a sensitivity of 0.38. When the CT esophagram and drain amylase were combined, the sensitivity rose to 0.69 with a specificity of 0.98. WBC elevation had a sensitivity of 0.92, with a specificity of 0.34. Among 30 patients with normal drain amylase and a normal WBC, one developed an anastomotic leak. Conclusions Drain amylase adds to the sensitivity of CT esophagram in the early detection of anastomotic leak. Selected patients with normal drain amylase levels and normal WBC may be able to safely forgo CT esophagram. PMID:27034784

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. New leak assembly based on fluidic nanochannels

    SciTech Connect

    Zhu, Aiqing; Zhao, Yongheng; Wang, Xudi; Wang, Yu; Wei, Wei; Qiu, Keqiang; Dong, Dong

    2016-09-15

    Fluidic nanochannels with a characteristic dimension of ∼280 nm were fabricated and designed as a leak assembly, where the nanochannels were formed on silicon wafers and enclosed with Pyrex{sup ®} glass. The geometric dimensions were characterized by scanning electron microscopy, and the gas flow conductance of He and other heavy gases (N{sub 2}, O{sub 2}, and Ar) was measured, and its uncertainty estimated, by the difference method. The results indicated that the measured flow conductance values were 45% less than the calculated flow conductance values. For helium, molecular flow was shown to occur at pressures ranging from vacuum to atmospheric pressure. As a consequence of the well-defined geometry, the prediction of flow conductance could be achieved for various gas species.

  9. Confidence leak in perceptual decision-making

    PubMed Central

    Rahnev, Dobromir; Koizumi, Ai; McCurdy, Li Yan; D’Esposito, Mark; Lau, Hakwan

    2015-01-01

    We live in a continuous environment in which the visual scene changes on a slow timescale. It has been shown that, to exploit such environmental stability, the brain creates a “continuity field” such that objects seen seconds ago influence the perception of current objects. What is unknown is whether a similar mechanism exists at the level of our metacognitive representations. In three experiments we demonstrate a robust inter-task “confidence leak” that cannot be explained by response priming or attentional fluctuations. Observers’ ability to modulate this confidence leak predicted higher capacity for metacognition as well as greater gray matter volume in the prefrontal cortex. A model based on normative principles from Bayesian inference explained the results by postulating that observers subjectively estimate the perceptual signal strength in a stable environment. These results point to the existence of a novel metacognitive mechanism mediated by regions in prefrontal cortex. PMID:26408037

  10. 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...

  11. 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...

  12. 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.

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

    NASA Technical Reports Server (NTRS)

    Larson, W. E.

    1985-01-01

    A voice-actuated wind tunnel model leak checking system was developed. The system uses a voice recognition and response unit to interact with the technician along with a graphics terminal to provide the technician with visual feedback while checking a model for leaks.

  14. 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.

  15. 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.

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. Detection of Gas Leaks in an Anaerobic Glove Box

    PubMed Central

    Jones, Gilda L.; Dever, Stanley M.

    1974-01-01

    An inert gas, Freon, can be added to the atmosphere of an anaerobic glove box without deleterious effect to cultures of anaerobic microorganisms. The sensitive probe of a Halogen Leak Detector passing over the outside surface of the box will pinpoint any escaping Freon and therefore locate the leak. PMID:4596756

  1. Detection of gas leaks in an anaerobic glove box.

    PubMed

    Jones, G L; Dever, S M

    1974-04-01

    An inert gas, Freon, can be added to the atmosphere of an anaerobic glove box without deleterious effect to cultures of anaerobic microorganisms. The sensitive probe of a Halogen Leak Detector passing over the outside surface of the box will pinpoint any escaping Freon and therefore locate the leak.

  2. 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...

  3. Air leak after lung resection: pathophysiology and patients’ implications

    PubMed Central

    Miserocchi, Giuseppe

    2016-01-01

    Protocols for the management of air leaks are critical aspects in the postoperative course of patients following lung resections. Many investigations in the last decade are focusing on the chest tube modalities or preventative measures, however, little is known about the pathophysiology of air leak and the patient perception of this common complication. This review concentrates on understanding the reasons why a pulmonary parenchyma may start to leak or an air leak may be longer than others. Experimental works support the notion that lung overdistension may favor air leak. These studies may represent the basis of future investigations. Furthermore, the standardization of nomenclature in the field of pleural space management and the creation of novel air leak scoring systems have contributed to improve the knowledge among thoracic surgeons and facilitate the organization of trials on this matter. We tried to summarize available evidences about the patient perception of a prolonged air leak and about what would be useful for them in order to prevent worsening of their quality of life. Future investigations are warranted to better understand the pathophysiologic mechanisms responsible of prolonged air leak in order to define tailored treatments and protocols. Improving the care at home with web-based telemonitoring or real time connected chest drainage may in a future improve the quality of life of the patients experience this complication and also enhance hospital finances. PMID:26941970

  4. Leak and obstruction with mask ventilation during simulated neonatal resuscitation.

    PubMed

    Schilleman, Kim; Witlox, Ruben S; Lopriore, Enrico; Morley, Colin J; Walther, Frans J; te Pas, Arjan B

    2010-11-01

    To evaluate mask technique during simulated neonatal resuscitation and test the effectiveness of training in optimal mask handling. Seventy participants(consultants, registrars and nurses) from neonatal units were asked to administer positive pressure ventilation at a flow of 8 l/min and a frequency of 40-60/min to a modified leak free, term newborn manikin (lung compliance 0.5 ml/cm H(2)O) using a Neopuff T-piece device. Recordings were made (1) before training, (2) after training in mask handling and (3) 3 weeks later. Leak was calculated. Obstruction (tidal volume <60% of optimal tidal volume) and severe obstruction (<30% of optimal tidal volume) were calculated when leak was minimal. For the 70 participants, median (IQR) leak was 71% (32-95%) before training, 10% (5-37%) directly after training and 15% (4-33%) 3 weeks later (p<0.001). When leak was minimal, gas flow obstruction was observed before, directly after training and 3 weeks later in 46%, 42% and 37% of inflations, respectively. Severe obstruction did not occur. Mask ventilation during simulated neonatal resuscitation was often hampered by large leaks at the face mask. Moderate airway obstruction occurred frequently when effort was taken to minimise leak. Training in mask ventilation reduced mask leak but should also focus on preventing airway obstruction.

  5. 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...

  6. 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...

  7. 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,...

  8. 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...

  9. 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,...

  10. 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,...

  11. From Hotel to High School: Converting a Residential Hotel into a New Type of Senior High School. Report and Recommendations of the Concourse Plaza High School Planning Committee.

    ERIC Educational Resources Information Center

    Sasserath, Simpson

    This document reports the result of a 5-day meeting held to recommend the structural building adaptations and the curriculum organization necessary to the renovation of Concourse Plaza Hotel into a high school. According to the planning committee, the hotel has many features adaptable to a school, which would permit a meaningful departure from the…

  12. [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.

  13. Assessing surgeon behavior change after anastomotic leak in colorectal surgery.

    PubMed

    Simianu, Vlad V; Basu, Anirban; Alfonso-Cristancho, Rafael; Thirlby, Richard C; Flaxman, Abraham D; Flum, David R

    2016-10-01

    Recency effect suggests that people disproportionately value events from the immediate past when making decisions, but the extent of this impact on surgeons' decisions is unknown. This study evaluates for recency effect in surgeons by examining use of preventative leak testing before and after colorectal operations with anastomotic leaks. Prospective cohort of adult patients (≥18 y) undergoing elective colorectal operations at Washington State hospitals participating in the Surgical Care and Outcomes Assessment Program (2006-2013). The main outcome measure was surgeons' change in leak testing from 6 mo before to 6 mo after an anastomotic leak occurred. Across 4854 elective colorectal operations performed by 282 surgeons at 44 hospitals, there was a leak rate of 2.6% (n = 124). The 40 leaks (32%) in which the anastomosis was not tested occurred across 25 surgeons. While the ability to detect an overall difference in use of leak testing was limited by small sample size, nine (36%) of 25 surgeons increased their leak testing by 5% points or more after leaks in cases where the anastomosis was not tested. Surgeons who increased their leak testing more frequently performed operations for diverticulitis (45% versus 33%), more frequently began their cases laparoscopically (65% versus 37%), and had longer mean operative times (195 ± 99 versus 148 ± 87 min), all P < 0.001. Recency effect was demonstrated by only one-third of eligible surgeons. Understanding the extent to which clinical decisions may be influenced by recency effect may be important in crafting quality improvement initiatives that require clinician behavior change. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Assessing Surgeon Behavior Change after Anastomotic Leak in Colorectal Surgery

    PubMed Central

    Simianu, Vlad V.; Basu, Anirban; Alfonso-Cristancho, Rafael; Thirlby, Richard C.; Flaxman, Abraham D.; Flum, David R.

    2016-01-01

    Background Recency effect suggests that people disproportionately value events from the immediate past when making decisions, but the extent of this impact on surgeons’ decisions is unknown. This study evaluates for recency effect in surgeons by examining use of preventative leak testing before and after colorectal operations with anastomotic leaks. Materials and Methods Prospective cohort of adult patients (≥18 years) undergoing elective colorectal operations at Washington State hospitals participating in the Surgical Care and Outcomes Assessment Program (2006–2013). The main outcome measure was surgeons’ change in leak testing from 6 months before to 6 months after an anastomotic leak occurred. Results Across 4,854 elective colorectal operations performed by 282 surgeons at 44 hospitals, there was a leak rate of 2.6% (n=124). The 40 leaks (32%) in which the anastomosis was not tested occurred across 25 surgeons. While the ability to detect an overall difference in use of leak testing was limited by small sample size, 9 (36%) of 25 surgeons increased their leak testing by 5 percent points or more after leaks in cases where the anastomosis was not tested. Surgeons who increased their leak testing more frequently performed operations for diverticulitis (45% vs 33%), more frequently began their cases laparoscopically (65% vs 37%), and had longer mean operative times (195±99 vs 148±87 minutes), all p<0.001. Conclusions Recency effect was demonstrated by only one-third of eligible surgeons. Understanding the extent to which clinical decisions may be influenced by recency effect may be important in crafting quality improvement initiatives that require clinician behavior change. PMID:27664886

  15. 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).

  16. 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

  17. Analysis of carboxyhemoglobin and cyanide in blood from victims of the Dupont Plaza Hotel fire in Puerto Rico.

    PubMed

    Levin, B C; Rechani, P R; Gurman, J L; Landron, F; Clark, H M; Yoklavich, M F; Rodriguez, J R; Droz, L; Mattos de Cabrera, F; Kaye, S

    1990-01-01

    Ninety-seven people died from a fire that occurred in the Dupont Plaza Hotel in Puerto Rico on 31 Dec. 1986. All, except four who died later in the hospital, were found dead at the scene. All of the fatalities at the hotel (except for eight) were burned beyond recognition. Blood from seventy-eight of the victims was screened for carboxyhemoglobin at the Institute for Forensic Sciences in Puerto Rico and was then sent to the National Institute of Standards and Technology, Gaithersburg, Maryland, for analysis of carboxyhemoglobin and cyanide concentrations. The blood data indicated that carbon monoxide and hydrogen cyanide, singly or combined, were probably not responsible for the majority of the deaths that occurred in the badly burned victims. On the other hand, the significantly higher carboxyhemoglobin in the nonburned victims indicated that carbon monoxide alone or combined with hydrogen cyanide probably played a major role in the cause of their deaths.

  18. 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

  19. 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

  20. Nasogastric placement of sump tube through the leak for the treatment of esophagogastric anastomotic leak after esophagectomy for esophageal carcinoma.

    PubMed

    Jiang, Feng; Yu, Ming Feng; Ren, Bin Hui; Yin, Guo Weng; Zhang, Qin; Xu, Lin

    2011-12-01

    We seek to retrospectively analyze the nasogastric placement of sump tube through the leak for the treatment of intra-thoracic esophagastric anastomotic leak after esophagectomy for esophageal carcinoma. Esophagectomy with intrathoracic esophagogastric anastomotic procedures were performed in 2954 patients who suffered from esophageal carcinoma in our hospital between May 2004 and July 2008. Anastomotic leak had developed in 38 patients, of whom four patients were treated by reoperations. Stent insertion, the traditional "three-tube method" and the nasogastric placement of sump tube through the leak were applied in two, seven, and 25 patients, respectively. The presence of anastomotic leak was proven by radiographic contrast examinations in 38 patients (1.3%). Among them, four received reoperations and recovered. Two patients were treated with the placement of self-expanding metallic coated stents and both died 10 and 13 d after placement due to uncontrollable hematemesis. Seven and 25 patients were managed by the traditional "three-tube method" and the nasogastric placement of sump tube through the leak, respectively. The mean time interval of the leak treatment was 42 d in the traditional "three-tube method" group and 31.2 d in the nasogastric placement of sump tube through the leak group, and the relatively average hospital mortality rates were 14.3% and 12%, respectively. The nasogastric placement of sump tube through the leak appears to be an effective, technically feasible, and minimally invasive option for the treatment of intrathoracic esophagogastric anastomotic leak. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. Air-leak effects on ear-canal acoustic absorbance.

    PubMed

    Groon, Katherine A; Rasetshwane, Daniel M; Kopun, Judy G; Gorga, Michael P; Neely, Stephen T

    2015-01-01

    Accurate ear-canal acoustic measurements, such as wideband acoustic admittance, absorbance, and otoacoustic emissions, require that the measurement probe be tightly sealed in the ear canal. Air leaks can compromise the validity of the measurements, interfere with calibrations, and increase variability. There are no established procedures for determining the presence of air leaks or criteria for what size leak would affect the accuracy of ear-canal acoustic measurements. The purpose of this study was to determine ways to quantify the effects of air leaks and to develop objective criteria to detect their presence. Air leaks were simulated by modifying the foam tips that are used with the measurement probe through insertion of thin plastic tubing. To analyze the effect of air leaks, acoustic measurements were taken with both modified and unmodified foam tips in brass-tube cavities and human ear canals. Measurements were initially made in cavities to determine the range of critical leaks. Subsequently, data were collected in ears of 21 adults with normal hearing and normal middle-ear function. Four acoustic metrics were used for predicting the presence of air leaks and for quantifying these leaks: (1) low-frequency admittance phase (averaged over 0.1-0.2 kHz), (2) low-frequency absorbance, (3) the ratio of compliance volume to physical volume (CV/PV), and (4) the air-leak resonance frequency. The outcome variable in this analysis was the absorbance change (Δabsorbance), which was calculated in eight frequency bands. The trends were similar for both the brass cavities and the ear canals. ΔAbsorbance generally increased with air-leak size and was largest for the lower frequency bands (0.1-0.2 and 0.2-0.5 kHz). Air-leak effects were observed in frequencies up to 10 kHz, but their effects above 1 kHz were unpredictable. These high-frequency air leaks were larger in brass cavities than in ear canals. Each of the four predictor variables exhibited consistent dependence on

  2. 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.

  3. 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

  4. 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.

  5. Performance of dust respirators with facial seal leaks. I. Experimental

    SciTech Connect

    Hinds, W.C.; Kraske, G.

    1987-10-01

    The ability of representative half-mask and single-use respirators with facial seal leaks to provide protection against aerosols was evaluated by experimental measurement. Respirators were mounted on a manikin in a test chamber and operated at seven steady flow rates over the range of 2 to 150 L/min. Samples of polydisperse and monodisperse aerosols were taken from inside and outside the respirator and analyzed by a calibrated optical particle counter over the particle-size range 0.1 to 11.3 ..mu..m. Measurements were made separately for filter performance as a function of particle size and flow rate, and simulated leak performance as a function of particle size, pressure drop, and leak size. Flow rate vs. pressure drop measurements were made for all filters and leaks tested. For a given leak condition the percentage of the total flow traversing the leak varied several fold over the usual range of airflow rates through a respirator. Aerosol penetration was found to depend strongly on particle size and flow rate for filters, and to depend strongly on particle size and less strongly on pressure drop for leaks. One can conclude from these measurements that the aerosol-size distribution inside a respirator will nearly always be significantly different from that outside the respirator.

  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. 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.

  8. 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

  9. 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

  10. 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.

  11. Risk of anastomotic leak after laparoscopic versus open colectomy.

    PubMed

    Murray, Alice C A; Chiuzan, Cody; Kiran, Ravi P

    2016-12-01

    Anastomotic leak following colorectal surgery is associated with significant morbidity and mortality. With the widespread adoption of laparoscopy, data from initial clinical trials evaluating the efficacy of laparoscopic when compared to open surgery may not currently be generalizable. We assess the risk of anastomotic leak after laparoscopic versus open colorectal resection using a nationwide database with standardized definitions. The 2012-2013 ACS-NSQIP targeted colectomy data were queried for all elective colorectal resections. Characteristics were compared for those patients undergoing laparoscopic versus open operations. Univariable and multivariable analyses, followed by a propensity score-matched analysis, were performed to assess the impact of laparoscopy on the development of an anastomotic leak. Of 23,568 patients, 3.4 % developed an anastomotic leak. Laparoscopic surgery was associated with a leak rate of 2.8 % (n = 425) and open surgery, 4.5 % (n = 378, p < 0.0001). Patients who developed a leak were more likely to die within 30 days of surgery (5.7 vs. 0.6 %, p < 0.0001). Patients who underwent laparoscopic surgery compared to open were younger (61 vs. 63 years, p = 0, p = 0.045) and with fewer comorbidities. On univariable analysis laparoscopic surgery was associated with reduced odds of developing an anastomotic leak (OR 0.60, p < 0.0001), and this remained after adjusting for all significant preoperative and disease-related confounders (OR 0.69, 95 % CI 0.58-0.82). A propensity score-matched analysis confirmed benefit of laparoscopic surgery over open surgery for anastomotic leak. Laparoscopic colectomy is safe and associated with reduced odds of developing an anastomotic leak following colectomy when controlling for patient-, disease- and procedure-related factors.

  12. Endobronchial Valves in the Treatment of Persistent Air Leaks.

    PubMed

    Hance, John M; Martin, Jeremiah T; Mullett, Timothy W

    2015-11-01

    Endobronchial valves (EBVs) are a useful adjunct in the management algorithm of patients with persistent pulmonary air leaks. They are increasingly used in the management of postsurgical parenchymal air leaks and carry a humanitarian use device exemption for this purpose. We report our experience with EBVs in the management of patients with bronchopleural fistula secondary to postsurgical intervention and spontaneous pneumothorax from medical comorbidities. An institutional review board-approved retrospective review was conducted of our single-center EBV experience. Patients were categorized as postsurgical versus medical. Data collected included demographic characteristics, indication for and number of valves placed, and chest tube duration before and after valve placement to evaluate overall resolution of air leak. Success was defined as resolution of air leak. A total of 14 valve placement procedures were performed. Mean age was 60 years and 10 patients were men. Eight represented prolonged leaks secondary to postsurgical complications and six were secondary to medical comorbidities. Indications for placement of valves in medical patients included persistent leak secondary to lung biopsy, ruptured bleb disease, and pneumothorax after cardiopulmonary resuscitation. Postsurgical indications included leaks secondary to lung biopsy, lobectomy, and ruptured bleb disease. A median of two valves were placed per procedure. A postprocedure median length of stay of 14.5 days was observed in the surgical group compared with 15 days in the medical group. Overall success rate was 57% (surgical group, 62.5%; medical group, 50%). EBVs are a useful adjunct in the management of persistent pulmonary air leaks, particularly when conventional interventions are contraindicated or not ideal. EBVs are well tolerated in the critically ill, have few known complications, are removable, and do not preclude future surgical intervention. Future studies should evaluate EBV efficacy versus

  13. Role of endoscopy to predict a leak after esophagectomy.

    PubMed

    Schaible, Anja; Ulrich, Alexis; Hinz, Ulf; Büchler, Markus W; Sauer, Peter

    2016-09-01

    After esophageal surgery, many centers conduct a routine diagnostic test before reintroducing oral intake. However, the clinical value in asymptomatic patients has been questioned. Therefore, we left this decision to the discretion of the operating surgeon and documented the data prospectively. Between 2007 and 2013, 185 consecutive patients underwent elective esophageal resection in our institution. The decision as to whether an endoscopy was to be performed as a routine-check or when a leak was clinically suspected was at the discretion of the operating surgeon. An immediate endoscopy was performed on emerging clinical signs of a leak. If a routine check was planned, it was performed between postoperative days 5-7. Of the 185 patients, 84 % had an endoscopy of the anastomosis during the hospital stay. Of the patients who underwent an endoscopy, 61 % were on a routine-check. In this group, one patient showed a leak at the time of endoscopy, 11 patients had pathological findings, 3 of these patients developed a leak later. Eighty-three patients had no pathological findings; nevertheless, 7 developed a leak later. In the on-demand-group, 10 patients showed a leak at the time of endoscopy. In a minority of patients, a routine-check of the anastomosis between days 5-7 revealed pathological findings that later led to an anastomotic leak (3/11). In contrast, a routine-check without pathological findings could not rule out the development of a future leak (7/83). Therefore, we conclude that routine postoperative studies to identify leaks after esophageal resection are not justified.

  14. 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

  15. Mass-Flow-Meter Leak-Testing System

    NASA Technical Reports Server (NTRS)

    Sorensen, Eric B.; Polidori, Andre V.; Heman, Joe R.; Dresser, Holland L.; Hellum, John

    1996-01-01

    Improved leak-testing system incorporates mass-flow meter as primary sensor for measurement of leakage rate. System easier to use and more reliable and enables leak tests to be completed in less time. Produces test data more plentiful, more accurate, and better suited to leak detection and diagnosis. Operates over range of test conditions, including pressures from atmospheric to 1,000 psi, temperatures from 50 to 120 degrees F and volumes from less than 1 in.(sup3) to 22 in.(sup3). Sensitive enough to measure absorbed gas seeping from O-ring seals after test pressure released.

  16. 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.

  17. 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.

  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. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 40 CFR 63.424 - Standards: Equipment leaks.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... inspection. A section of the log shall contain a list, summary description, or diagram(s) showing the... implement an instrument leak monitoring program that has been demonstrated to the Administrator as at least...

  6. 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 ...

  7. 10 CFR 39.35 - Leak testing of sealed sources.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... must be performed using a leak test kit or method approved by the Commission or an Agreement State. The... performed by a person approved by the Commission or an Agreement State to perform the analysis. (c)...

  8. 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...

  9. 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...

  10. 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...

  11. 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.

  12. 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.

  13. 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.

  14. 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...

  15. 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...

  16. 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...

  17. 40 CFR 63.1410 - Equipment leak provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CFR part 63, subpart UU (national emission standards for equipment leaks (control level 2)) for all... of 40 CFR part 63, subpart SS, as referred to by 40 CFR part 63, subpart UU, the following apply for...

  18. 40 CFR 63.1410 - Equipment leak provisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CFR part 63, subpart UU (national emission standards for equipment leaks (control level 2)) for all... of 40 CFR part 63, subpart SS, as referred to by 40 CFR part 63, subpart UU, the following apply for...

  19. 40 CFR 63.1410 - Equipment leak provisions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the requirements of 40 CFR part 63, subpart UU (national emission standards for equipment leaks... with the requirements of 40 CFR part 63, subpart SS, as referred to by 40 CFR part 63, subpart UU, the...

  20. 40 CFR 63.1410 - Equipment leak provisions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... the requirements of 40 CFR part 63, subpart UU (national emission standards for equipment leaks... with the requirements of 40 CFR part 63, subpart SS, as referred to by 40 CFR part 63, subpart UU, the...

  1. 40 CFR 63.1410 - Equipment leak provisions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... CFR part 63, subpart UU (national emission standards for equipment leaks (control level 2)) for all... of 40 CFR part 63, subpart SS, as referred to by 40 CFR part 63, subpart UU, the following apply for...

  2. Transcatether closure of an atrial redirection baffle leak

    PubMed Central

    Soriano, Brian D; Stout, Karen K; Cailes, Colleen D; Jones, Thomas K

    2009-01-01

    We present the case of a woman born with transposition of the great arteries, who was surgically repaired with the Mustard technique. Because of interatrial shunting, she was brought to the cardiac catheterization laboratory for device closure. Matrix-array 3D transesophageal echocardiography enabled visualization of both baffle leaks and demonstrated its orientation in a fashion superior to 2D imaging, had it been used alone. The leaks were successfully closed with a single transcatheter device. PMID:20300277

  3. Transcatether closure of an atrial redirection baffle leak.

    PubMed

    Soriano, Brian D; Stout, Karen K; Cailes, Colleen D; Jones, Thomas K

    2009-01-01

    We present the case of a woman born with transposition of the great arteries, who was surgically repaired with the Mustard technique. Because of interatrial shunting, she was brought to the cardiac catheterization laboratory for device closure. Matrix-array 3D transesophageal echocardiography enabled visualization of both baffle leaks and demonstrated its orientation in a fashion superior to 2D imaging, had it been used alone. The leaks were successfully closed with a single transcatheter device.

  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. Offsite Radiological Consequence Analysis for the Waste Transfer Leak

    SciTech Connect

    ZIMMERMAN, B.D.

    2003-07-30

    This document quantifies the offsite radiological consequence of the bounding waste transfer leak accident for comparison with the 25 rem Evaluation Guideline established in DOE-STD-3009, Appendix A. The bounding waste transfer leak accident is a large pipe break into a pit. The calculated offsite dose does not challenge the Evaluation Guidelines. Revision 1 incorporates comments received from the Office of River Protection.

  6. Cerebellar hemorrhage caused by cerebrospinal fluid leak after spine surgery.

    PubMed

    Farag, Ehab; Abdou, Amgad; Riad, Ihab; Borsellino, Sam R; Schubert, Armin

    2005-02-01

    Spine surgery is associated with a wide range of surgical and anesthetic complications. Excessive cerebrospinal fluid leak can be a cause of cerebellar hemorrhage postoperatively. We report a 43-yr-old patient who had lumbar spine reexploration surgery complicated by a cerebrospinal fluid leak which led to cerebellar hemorrhage manifested by postoperative mental status changes. Early detection and proper management resulted in full recovery.

  7. 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.

  8. 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

  9. 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.

  10. 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'.

  11. 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.

  12. Fixing the Leak: Empirical Corrections for the Small Light Leak in Hinode XRT

    NASA Astrophysics Data System (ADS)

    Saar, Steven H.; DeLuca, E. E.; McCauley, P.; Kobelski, A.

    2013-07-01

    On May 9, 2012, the the straylight level of XRT on Hinode suddenly increased, consistent with the appearance of a pinhole in the entrance filter (possibly a micrometeorite breach). The effect of this event is most noticeable in the optical G band data, which shows an average light excess of ~30%. However, data in several of the X-ray filters is also affected, due to low sensitivity "tails" of their filter responses into the visible. Observations taken with the G band filter but with the visible light shutter (VLS) closed show a weak, slightly shifted, out-of-focus image, revealing the leaked light. The intensity of the leak depends on telescope pointing, dropping strongly for images taken off-disk. By monitoring light levels in the corners of full-Sun Ti-poly filter images, we determine the approximate time of the event: ~13:30 UT. We use pairs of images taken just-before and after the filter breach to directly measure the leakage in two affected X-ray filters. We then develop a model using a scaled, shifted, and smoothed versions of the VLS closed images to remove the contamination. We estimate the uncertainties involved in our proposed correction procedure. This research was supported under NASA contract NNM07AB07C for Hinode XRT.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. Reduction of persistent air leak with endoscopic valve implants

    PubMed Central

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

    2007-01-01

    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. PMID:17726171

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Endoscopic vacuum-assisted closure of upper intestinal anastomotic leaks.

    PubMed

    Wedemeyer, Jochen; Schneider, Andrea; Manns, Michael P; Jackobs, Steffan

    2008-04-01

    Management of intrathoracic anastomotic leaks remains an interdisciplinary challenge. Established treatment options include percutaneous drainage, endoscopic closure, or even surgical revision. All these procedures are associated with high morbidity and mortality rates. We report a new, effective endoscopic treatment option for intrathoracic esophageal anastomotic leaks by using an endoscopic vacuum-assisted closure system. Two patients with intrathoracic anastomotic leaks after esophagectomy and gastrectomy were included. Surgical reinterventions failed to seal the leaks in 1 patient, whereas in the other patient the anastomotic leakage persisted after endoscopic placement of 2 covered self-expanding metal stents. We endoscopically placed transnasal draining tubes that were armed with a size-adjusted sponge at their distal tip in the necrotic anastomotic cavities. Continuous suction was applied. Sponge and drain were changed twice a week. No complications were noted during the course of treatment. After a median of 15 days, closure of the wound cavities was achieved in all cases. A median of 5 endoscopic interventions was necessary. Both patients returned gradually to a solid diet without recurrence of the leaks. Endoscopic vacuum-assisted closure might be an effective alternative in the treatment of upper intestinal anastomotic leaks.

  4. 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

  5. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. 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

  7. 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.

  8. Reproductive pattern of Cuban women living in the municipality of Plaza de la Revolución, Havana, Cuba.

    PubMed

    Vázquez, Vanessa; Camargo, Ana M; Acosta, Marlen; Alonso, Verónica; Luna, Francisco

    2015-07-01

    This paper assesses the reproductive and abortion patterns of women living in Plaza de la Revolución, a municipality of Havana, Cuba, by studying the factors influencing birth and abortion rates. Socio-demographic data and female reproductive histories were collected in a survey of 1200 post-menopausal women living in the municipality. Average ages at menarche and at menopause were 12.71 and 48.39 years, respectively, thus yielding a potential long reproductive period of 35.68 years, indicating high fertility. Although the mean pregnancy rate was 3.81 pregnancies per woman, the live birth rate at time of delivery was only 1.89 due to the high rate of abortions: 40% of all pregnancies were voluntarily interrupted. Among the biological and socio-cultural variables that were found to influence the rate of live births were those related marriage pattern, especially age at first union. Demographic variables such as pregnancy order, maternal age and marital status were the main determinants of the abortion pattern, with abortion being used as a method of birth control in order to obtain the desired family size, and most women (75.2%) using contraceptives.

  9. 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.

  10. 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.

  11. NOEL: a no-leak fusion blanket concept

    SciTech Connect

    Powell, J R; Yu, W S; Fillo, J A; Horn, F L; Makowitz, H

    1980-01-01

    Analysis and tests of a no-leak fusion blanket concept (NOEL-NO External Leak) are described. Coolant cannot leak into the plasma chamber even if large through-cracks develop in the first wall. Blanket modules contain a two-phase material, A, that is solid (several cm thick) on the inside of the module shell, and liquid in the interior. The solid layer is maintained by imbedded tubes carrying a coolant, B, below the freezing point of A. Most of the 14-MeV neutron energy is deposited as heat in the module interior. The thermal energy flow from the module interior to the shell keeps the interior liquid. Pressure on the liquid A interior is greater than the pressure on B, so that B cannot leak out if failures occur in coolant tubes. Liquid A cannot leak into the plasma chamber through first wall cracks because of the intervening frozen layer. The thermal hydraulics and neutronics of NOEL blankets have been investigated for various metallic (e.g., Li, Pb/sub 2/, LiPb, Pb) and fused salt choices for material A.

  12. [Determination of creatinine in drained liquid. Urinary leak or lymphocele?].

    PubMed

    Flores-Gama, Francisco; Bochicchio-Riccardelli, Tommaso; Mondragón-Ramírez, Guillermo

    2010-01-01

    Liquid collections around the renal graft that are displayed in 51% of cases implicate a diagnostic challenge and a risk for graft function. We undertook this study to determine the usefulness of creatinine concentration measurement in drainage in patients with renal transplantation. We selected patients with surgically corrected urinary leak and patients with lymphocele from November 1, 1999, to November 30, 2008, in whom we determined the creatinine concentration in liquid drainage, plasma and urine. We included five patients with urinary leak and six patients with lymphocele. Two patients had urinary leak before the lymphocele. The t value of the plasma creatinine (Pcreat), drainage (Dcreat) and urine (Ucreat) was 0.89, 0.045 and 0.63, respectively. The diagnostic criteria of urinary leak represented a value between the creatinine of the drainage and plasma (D/Pcreat) >6, between urine and drainage (U/Dcreat) <3 and between urine and plasma (U/ Pcreat) <7. When we compared both groups the χ(2) values were 0.018, 0.007 and 0.094, respectively. There is a statistically significant difference among the creatinine drainage liquid values. Our study shows that D/Pcreat ratio >6 after the first week or U/Dcreat ratio <3 at any time during the postoperative period represents a six-times higher possibility of urinary leak.

  13. Assessing the Rayleigh Intensity Remote Leak Detection Technique

    NASA Technical Reports Server (NTRS)

    Clements, Sandra

    2001-01-01

    Remote sensing technologies are being considered for efficient, low cost gas leak detection. An exploratory project to identify and evaluate remote sensing technologies for application to gas leak detection is underway. During Phase 1 of the project, completed last year, eleven specific techniques were identified for further study. One of these, the Rayleigh Intensity technique, would make use of changes in the light scattered off of gas molecules to detect and locate a leak. During the 10-week Summer Faculty Fellowship Program, the scatter of light off of gas molecules was investigated. The influence of light scattered off of aerosols suspended in the atmosphere was also examined to determine if this would adversely affect leak detection. Results of this study indicate that in unconditioned air, it will be difficult, though perhaps not impossible, to distinguish between a gas leak and natural variations in the aerosol content of the air. Because information about the particle size distribution in clean room environments is incomplete, the applicability in clean rooms is uncertain though more promising than in unconditioned environments. It is suggested that problems caused by aerosols may be overcome by using the Rayleigh Intensity technique in combination with another remote sensing technique, the Rayleigh Doppler technique.

  14. Endoscopic repair of frontal sinus cerebrospinal fluid leaks.

    PubMed

    Woodworth, B A; Schlosser, R J; Palmer, J N

    2005-09-01

    To describe endoscopic management of frontal sinus cerebrospinal fluid (CSF) leaks. Retrospective. We reviewed all frontal sinus CSF leaks treated using an endoscopic approach at our institutions from 1998 to 2003. CSF leaks originated immediately adjacent to or within the frontal recess or frontal sinus proper for inclusion in the study. Data collected included demographics, presenting signs and symptoms, site and size of skull-base defect, surgical approach, repair technique, and clinical follow up. Seven frontal sinus CSF leaks in six patients were repaired endoscopically. Average age of presentation was 45 years (range 25-65 years). Aetiology was idiopathic (three), congenital (one), accidental trauma (one), and surgical trauma (two). All patients presented with CSF rhinorrhea; two patients presented with meningitis. Four defects originated in the frontal recess, while two others involved the posterior table and frontal sinus outflow tract. Four patients had associated encephaloceles. We performed endoscopic repair in all six patients with one patient requiring an adjuvant osteoplastic flap without obliteration. All repairs were successful at the first attempt with a mean follow up of 13 months. All frontal sinuses remained patent on both post-operative endoscopic and radiographic exam. Endoscopic repair of frontal sinus CSF leaks and encephaloceles can be an effective method if meticulous attention is directed toward preservation of the frontal sinus outflow tract, thus avoiding an osteoplastic flap and obliteration. The major limiting factor for an endoscopic approach is extreme extension superiorly or laterally within the posterior table beyond the reach of current instrumentation.

  15. 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).

  16. 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

  17. 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. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Optimization of the leak conductance in the squid giant axon

    NASA Astrophysics Data System (ADS)

    Seely, Jeffrey; Crotty, Patrick

    2010-08-01

    We report on a theoretical study showing that the leak conductance density, GL , in the squid giant axon appears to be optimal for the action potential firing frequency. More precisely, the standard assumption that the leak current is composed of chloride ions leads to the result that the experimental value for GL is very close to the optimal value in the Hodgkin-Huxley model, which minimizes the absolute refractory period of the action potential, thereby maximizing the maximum firing frequency under stimulation by sharp, brief input current spikes to one end of the axon. The measured value of GL also appears to be close to optimal for the frequency of repetitive firing caused by a constant current input to one end of the axon, especially when temperature variations are taken into account. If, by contrast, the leak current is assumed to be composed of separate voltage-independent sodium and potassium currents, then these optimizations are not observed.

  19. 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.

  20. 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.

  1. Leak-rate qualification of the FFTF control area

    SciTech Connect

    Billings, M.P.; Swenson, L.D.

    1983-06-01

    Positive experience with the Fast Flux Test Facility (FFTF) Control Area boundary has demonstrated that strigent requirements for reactor control room leak-tightness can be met and maintained. Guidance contained in 10CFR50, Appendix A, Criteria 4 and 19, and Regulatory Guides 1.78 and 1.95 provided criteria for control room habitability, to provide safe, central control of the FFTF plant under normal and accident conditions. A leak rate criterion of 178 scfm for the approximate 53,000 cu. ft. Volume of the Control Area was established for the limiting condition of airborne sodium oxide aerosols from a postulated fire in one of the three secondary sodium loops. Numerous tests utilizing a variety of leak identification techniques were conducted.

  2. 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).

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Modeling the GPR response of leaking, buried pipes

    SciTech Connect

    Powers, M.H.; Olhoeft, G.R.

    1996-11-01

    Using a 2.5D, dispersive, full waveform GPR modeling program that generates complete GPR response profiles in minutes on a Pentium PC, the effects of leaking versus non-leaking buried pipes are examined. The program accounts for the dispersive, lossy nature of subsurface materials to GPR wave propagation, and accepts complex functions of dielectric permittivity and magnetic permeability versus frequency through Cole-Cole parameters fit to laboratory data. Steel and plastic pipes containing a DNAPL chlorinated solvent, an LNAPL hydrocarbon, and natural gas are modeled in a surrounding medium of wet, moist, and dry sand. Leaking fluids are found to be more detectable when the sand around the pipes is fully water saturated. The short runtimes of the modeling program and its execution on a PC make it a useful tool for exploring various subsurface models.

  9. The missing leak: a case report of a baffle-leak closure using real-time 3D transoesophageal guidance.

    PubMed

    Klein, Andrew J; Kim, Michael S; Salcedo, Ernesto; Fagan, Thomas; Kay, Joseph

    2009-05-01

    Brady-arrhythmias in patients undergone atrial switch procedures (Mustard or Senning procedure) for complete transposition of the great arteries (TGA) are common and often require implantation of permanent pacemakers. It has been shown that in patients with palliated congenital cardiac defects with residual intra-cardiac shunts, permanent pacemaker implantation is associated with an increased risk of thrombo-embolism. Patients with TGA and concomitant baffle leaks may have an even further increased thrombo-embolic risk, given that the leaks can provide the conduit for venous to systemic thrombo-embolism. In order to decrease this risk, all TGA patients who require pacemaker implantation typically undergo a thorough pre-procedural evaluation to assess for the presence of a baffle leak. Traditional imaging modalities, however, are often limited in their ability to detect and/or properly locate small baffle leaks. We report a case of a patient with TGA and a baffle leak that was both identified and percutaneously closed with the assistance of real-time 3D transoesophageal echocardiography.

  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. The Soil Microbial Response to a Massive Natural Gas Leak

    NASA Astrophysics Data System (ADS)

    Tavormina, P. L.; Newman, S.; Shen, L.; Connon, S. A.; Okumura, M.; Orphan, V. J.

    2016-12-01

    The 2015/2016 gas leak in the Porter Ranch community (Southern California) was the largest natural gas leak in US history. While considerable attention has focused on the amount of methane released to the atmosphere and the effects of other gas components on human well-being, less attention has been given to the response of soil microbes to this event. These microbes represent natural pathways for utilization of C1 compounds in soils and, possibly, untapped potential to remediate natural and anthropogenic gas emissions. We monitored onsite and background soil methane concentrations and microbial communities during and following the Porter Ranch gas leak. Soil core samples (25cm depth, collected twice monthly beginning in January 2016) were preserved for DNA, RNA, microscopic, stable isotope probing, and chromatographic methods. Simultaneously to coring, gas from soil pore spaces was collected for cavity ringdown spectroscopy to measure carbon dioxide, methane and ethane concentrations, and estimate corresponding isotopic values in carbon dioxide and methane. By pairing these measurements with high throughput sequencing, transcript analysis, and cultivation, we demonstrate discrete shifts in the total microbial community in surface (0 - 5 cm) and deep (20 - 25 cm) soils. Importantly, we find that methane consumption likely occurred in surface soils during and following the leak. The lineages most significantly correlated with elevated methane from the leak event were five orders of magnitude more abundant near the leak event in space and time, indicating a microbial bloom. These lineages are previously unrecognized members of Sphingomonadaceae, and they encode at least two biochemical pathways for methane oxidation. Cultivation of the first representative of this group now allows more detailed investigation into its capacity for microbially-mediated soil methane oxidation and mitigation.

  12. Prospective evaluation of biodegradable polymeric sealant for intraoperative air leaks.

    PubMed

    Park, Bernard J; Snider, John M; Bates, Nathan R; Cassivi, Stephen D; Jett, G Kimble; Sonett, Joshua R; Toloza, Eric M

    2016-12-12

    A biodegradable polymeric sealant has been previously shown to reduce postoperative air leaks after open pulmonary resection. The aim of this study was to evaluate safety and efficacy during minimally invasive pulmonary resection. In a multicenter prospective single-arm trial, 112 patients with a median age of 69 years (range 34-87 years) were treated with sealant for at least one intraoperative air leak after standard methods of repair (sutures, staples or cautery) following minimally invasive pulmonary resection (Video-Assisted Thoracic Surgery (VATS) or Robotic-Assisted). Patients were followed in hospital and 1 month after surgery for procedure-related and device-related complications and presence of air leak. Forty patients had VATS and 72 patients had Robotic-Assisted procedures with the majority (80/112, 71%) undergoing anatomic resection (61 lobectomy, 13 segmentectomy, 6 bilobectomy). There were no device-related adverse events. The overall morbidity rate was 41% (46/112), with major complications occurring in 16.1% (18/112). In-hospital mortality and 30-day mortality were 1.9% (2/103). The majority of intraoperative air leaks (107/133, 81%) were sealed after sealant application, and an additional 16% (21/133) were considered reduced. Forty-nine percent of patients (55/112) were free of air leak throughout the entire postoperative study period. Median chest tube duration was 2 days (range 1 - 46 days), and median length of hospitalization was 3 days (range 1 - 20 days). This study demonstrated that use of a biodegradable polymer for closure of intraoperative air leaks as an adjunct to standard methods is safe and effective following minimally invasive pulmonary resection. ClinicalTrials.gov: NCT01867658 . Registered 3 May 2013.

  13. 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.

  14. 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.

  15. 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

  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 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.

  18. [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.

  19. STIS-ACS Red Leak Cross-Calibration

    NASA Astrophysics Data System (ADS)

    Chiaberge, Marco

    2009-07-01

    We observe one type K star {G Gem} with ACS/SBC and STIS in order to determine the throughput in the red leak of both the SBC and the STIS FUV-MAMA. We will also observe the type G9V star HD53143 with the SBC with all long-pass filters and the PR130L in order to compare the observed fluxes and the spectrum with a previous prism observation of the same star and investigate the possible time dependence of the red leak.

  20. 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.

  1. Leaking And Non-leaking Systems: Study Of Natural CO2 Accumulations For Geological Sequestration

    NASA Astrophysics Data System (ADS)

    Voltattorni, N.; Cantucci, B.; Cinti, D.

    2008-12-01

    The potential risks of geological CO2 storage must be understood and geologists are required to predict how CO2 may behave once stored underground. As natural geological accumulations of carbon dioxide occur in many basins in Italy and volcanic and seismically active areas allow CO2 rich fluids to migrate to the near surface, many of these areas have been investigated in order to study long-term geochemical processes that may occur following geological storage of anthropogenic CO2. A study representing an example of "leaking" system is the Solfatara crater (Campi Flegrei, Southern Italy) characterised by the presence of both CO2 rich-waters and fumarole. Soil gas flux measurements show that the entire area discharges between 1200 and 1500 tons of CO2 a day. Most part of analysed waters is the effect of a mixing between a shallow meteoric water and a deep thermal Na-Cl end-member and/or seawater, resulting in sodium-chloride waters. A high dissolved CO2 content (max value 566.28 cc/l) is also present. Furthermore, the Campi Flegrei frequently undergo bradyseism related to the elastic response of the shallow crust to increasing pressure within a shallow magma chamber. The study of this phenomenon could be useful to detect ground deformation linked to geomechanical changes in a geological CO2 reservoir. In contrast, an example of "non-leaking" system is the Pisticci oil and gas Field (Southern Italy) where a great variety of hydrocarbons traps are formed by horst and tilted blocks in the Mesozoic carbonate substratum covered by an almost continuous sequence of Lower Pliocene marls and Middle Pliocene-Pleistocene marly blue clays. Soil gas surveys were performed after a MD 4.5 earthquake and two years later to test the permanence of the gas distribution pattern. CO2 distribution in soil gas seems not to be affected by changes in stress, as suggested by the average values of both surveys. The principal aim of our research has been to evaluate and mitigate risks for

  2. 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

  3. 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 (CONTINUED) National Emission Standards for Hazardous Air...

  4. 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...

  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. 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.

  7. 40 CFR 61.135 - Standard: Equipment leaks.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... shall be repaired as soon as practicable, but no later than 15 calendar days after it is detected... calendar days after each leak is detected. (e) Each exhauster equipped with a seal system that includes a... system that purges the barrier fluid into a process stream with zero benzene emissions to the atmosphere...

  8. 40 CFR 61.135 - Standard: Equipment leaks.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... shall be repaired as soon as practicable, but no later than 15 calendar days after it is detected... calendar days after each leak is detected. (e) Each exhauster equipped with a seal system that includes a... system that purges the barrier fluid into a process stream with zero benzene emissions to the atmosphere...

  9. 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.

  10. Leak detection system and control using non-rigid bladder

    SciTech Connect

    Pillette, K.P.

    1980-11-11

    A portable system for early detection of leaks from suspect piping fittings, for example, as used on the ''christmas tree'' portion of a gas well provides an encapsulating bladder which sealably encapsulates the suspect fitting and collects leaks from the fitting. The apparatus provides, in the preferred embodiment, a bladder which can encase any suspect portion of the christmas tree (Or like piping system), such as for example, the choke jacket or other like fittings where maximum turbulence occurs as when gas or oil mixed with sand flows through the fitting. In the preferred embodiment, the collection of a leak within the bladder causes a regulator to operate a control valve and halt the flow of gas, oil, or like flowing material through the piping system of which the suspect fitting is a part. The system can be applied to any other similar existing and operating piping arrangement where the detection of leaks from suspect fittings is desirable. The portable bladder and shut off arrangement of the present invention has particular application in the offshore oil and gas industry, where it can perform a safety function on unmanned gas/oil well platforms.

  11. 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…

  12. 10 CFR 36.59 - Detection of leaking sources.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... water. If a check for contamination is done by analysis of a sample of pool water, the results of the... certificate from a transferor that leak test has been done within the 6 months before the transfer. Water from the pool must be checked for contamination each day the irradiator operates. The check may be...

  13. 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 NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39... form; (4) Sources of beta- or gamma-emitting radioactive material with an activity of 3.7 MBq or less...

  14. 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 NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39... form; (4) Sources of beta- or gamma-emitting radioactive material with an activity of 3.7 MBq or less...

  15. 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.

  16. 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.

  17. 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.

  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. 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. Copyright © 2013 Sociedade Portuguesa de Pneumologia. Published by Elsevier España. All rights reserved.

  20. Methane Leak Detection and Emissions Quantification with UAVs

    NASA Astrophysics Data System (ADS)

    Barchyn, T.; Fox, T. A.; Hugenholtz, C.

    2016-12-01

    Robust leak detection and emissions quantification algorithms are required to accurately monitor greenhouse gas emissions. Unmanned aerial vehicles (UAVs, `drones') could both reduce the cost and increase the accuracy of monitoring programs. However, aspects of the platform create unique challenges. UAVs typically collect large volumes of data that are close to source (due to limited range) and often lower quality (due to weight restrictions on sensors). Here we discuss algorithm development for (i) finding sources of unknown position (`leak detection') and (ii) quantifying emissions from a source of known position. We use data from a simulated leak and field study in Alberta, Canada. First, we detail a method for localizing a leak of unknown spatial location using iterative fits against a forward Gaussian plume model. We explore sources of uncertainty, both inherent to the method and operational. Results suggest this method is primarily constrained by accurate wind direction data, distance downwind from source, and the non-Gaussian shape of close range plumes. Second, we examine sources of uncertainty in quantifying emissions with the mass balance method. Results suggest precision is constrained by flux plane interpolation errors and time offsets between spatially adjacent measurements. Drones can provide data closer to the ground than piloted aircraft, but large portions of the plume are still unquantified. Together, we find that despite larger volumes of data, working with close range plumes as measured with UAVs is inherently difficult. We describe future efforts to mitigate these challenges and work towards more robust benchmarking for application in industrial and regulatory settings.

  1. 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...

  2. 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...

  3. 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.

  4. 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.

  5. 40 CFR 1065.345 - Vacuum-side leak verification.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... zero flow, or by detecting the dilution of a known concentration of span gas when it flows through the... bypass flows as an approximation of the system's normal in-use flow rate. (d) Dilution-of-span-gas leak... recommend using only analyzers that have a repeatability of 0.5% or better at the span gas concentration...

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

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... zero flow, or by detecting the dilution of a known concentration of span gas when it flows through the... bypass flows as an approximation of the system's normal in-use flow rate. (d) Dilution-of-span-gas leak... recommend using only analyzers that have a repeatability of 0.5% or better at the span gas concentration...

  7. 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...

  8. 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...

  9. 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...

  10. T Plant secondary containment and leak detection upgrades

    SciTech Connect

    Carlson, T.A.

    1995-10-19

    The W-259 project will provide upgrades to the 2706-T/TA Facility to comply with Federal and State of Washington environmental regulations for secondary containment and leak detection. The project provides decontamination activities supporting the environmental restoration mission and waste management operations on the Hanford Site.

  11. 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

  12. 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

  13. 40 CFR 1065.345 - Vacuum-side leak verification.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... zero flow, or by detecting the dilution of a known concentration of span gas when it flows through the... bypass flows as an approximation of the system's normal in-use flow rate. (d) Dilution-of-span-gas leak... recommend using only analyzers that have a repeatability of 0.5% or better at the span gas concentration...

  14. 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.

  15. 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...

  16. 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.

  17. 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...

  18. 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.

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. Plasma Crystal-3 Plus experiment Chamber Leak Check

    NASA Image and Video Library

    2010-07-01

    ISS024-E-007144 (1 July 2010) --- Russian cosmonaut Alexander Skvortsov, Expedition 24 commander, performs chamber leak checks on the new Plasma Crystal-3 Plus experiment in the Poisk Mini-Research Module 2 (MRM2) of the International Space Station.

  7. 40 CFR 63.1331 - Equipment leak provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... for pumps in ethylene glycol service where the pump seal is designed to weep fluid shall not be considered to be a leak. Ethylene glycol dripping from pump seals must be captured in a catchpan and returned... subpart, except for ethylene glycol which need not be considered. (8) When the provisions of subpart H of...

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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..

  14. Standardized Approach to Prolonged Air Leak Reduction After Pulmonary Resection.

    PubMed

    Drahush, Nicholas; Miller, Ashley D; Smith, Jeremiah S; Royer, Anna M; Spiva, Marlana; Headrick, James R

    2016-06-01

    Prolonged air leaks after pulmonary resection lead to patient discomfort, increased hospital length of stay, greater health care costs, and increased morbidity. A standardized approach to air leak reduction (STAR) after lung resection was developed and studied. A retrospective review was conducted of a prospective database from 1 surgeon who had adopted STAR as standard of care. Three independent factors shown to reduce air leaks are incorporated in STAR: fissureless operative technique, staple line buttressing, and protocol-driven chest tube management. Patient characteristics and outcomes were compared against aggregate data from The Society of Thoracic Surgeons National Database (2012-2014). From June 2010 through May 2015, 475 patients met the study criteria. Of these, 264 (55.6%) had lobectomies, 198 (41.7%) had wedge resections, and 13 (2.7%) had segmentectomies. Prolonged air leaks were reduced in the STAR lobectomy group by 52% (5.7% versus 10.9%; p = 0.0079) and in the STAR wedge group by 40% (2.5% versus 4.2%; p = 0.38). Hospital length of stay for lobectomies (3.2 versus 6.3 days; p = 0.0001), wedge resections (3.3 versus 4.5 days; p = 0.0152), and segmentectomies (3.2 versus 5.2 days; p = 0.0001) was significantly reduced. Readmission rate was 4% and none were related to air leak. No difference was seen in mortality rates. Use of STAR for pulmonary resection, particularly for lobectomies, shows decreased postoperative prolonged air leaks when compared with The Society of Thoracic Surgeons National Database. This aggressive approach did not lead to air leak-related hospital readmissions nor compromise postoperative mortality. The STAR protocol is an innovative strategy that has the potential to improve postoperative pulmonary resection outcomes. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. INNOVATIVE ACOUSTIC SENSOR TECHNOLOGIES FOR LEAK DETECTION IN CHALLENGING PIPE TYPES

    DTIC Science & Technology

    2016-12-01

    ft 1 in. per 1000 ft Note: Manufacturer-supplied performance specifications. Gutermann does not specify a minimum detectable leak size...activate at night to monitor for acoustic leak signatures when background noise is at a minimum and pipeline water pressure is highest. For example, the...Sensor Installation and Performance for Leak Detection Pipe Type Recommended Sensor Type Suggested Sensor Spacing Minimum Detectable Leak Size

  1. 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.

  2. 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…

  3. 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…

  4. 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.

  5. 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.

  6. 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...

  7. 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.

  8. 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...

  9. Management of an Esojejunal Intrathoracic Leak Using an Endoscopic Vacuum-assisted Closure Technique.

    PubMed

    Barabino, Gabriele; Filippello, Alexandre; Brek, Amine; Cuilleron, Muriel; Dumas, Olivier; Rinaldi, Leslie; Porcheron, Jack

    2017-06-01

    Management of intrathoracic anastomotic leaks remains an important clinical challenge. We describe a case about a patient with intrathoracic esophageal anastomotic leaks after oesogastrectomy. Ndoscopic Vacuum-assisted closure technique today is an effective alternative in the treatment of anastomotic leaks after upper gastrointestinal tract surgery.

  10. 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.

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

    DOEpatents

    Claytor, Thomas N.

    1981-01-01

    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.

  12. 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.

  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. 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.

  16. In-line flow control blocks risky leaks

    SciTech Connect

    Nolan, W.A.

    1995-01-01

    Excess flow valves work alone or in conjunction with expensive monitoring equipment to prevent accidental releases of hazardous materials. Recently in Boynton Beach, Florida, 500 pounds of chlorine gas was accidentally released from a water treatment plant. This accident forced the 4,000 residents of Boynton Beach to evacuate their homes. Area schools also shut down as the cloud drifted west and another 1,000 residents left the area. Investigators blamed the chlorine gas leak on a line failure. The chlorine ate a hole in a copper plug in a gas regulator. Workers were unable to detect the leak until it became dangerous. The in-line device stops accidental releases used in process flow industries. The operation of the valve and applications are discussed.

  17. 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

  18. 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.

  19. 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.

  20. 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).

  1. 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...

  2. 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.

  3. 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

  4. 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...

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Indian Country Leaking Underground Storage Tanks, Region 9, 2016

    EPA Pesticide Factsheets

    This GIS dataset contains point features that represent Leaking Underground Storage Tanks in US EPA Region 9 Indian Country. This dataset contains facility name and locational information, status of LUST case, operating status of facility, inspection dates, and links to No Further Action letters for closed LUST cases. This database contains 1230 features, with 289 features having a LUST status of open, closed with no residual contamination, or closed with residual contamination.

  15. 40 CFR 53.52 - Leak check test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... associated with this test are summarized in table E-1 of this subpart. The candidate test sampler must meet... checked at zero and one or more non-zero flow rates within 7 days of use for this test. (e) Test setup. (1... 40 Protection of Environment 6 2013-07-01 2013-07-01 false Leak check test. 53.52 Section 53.52...

  16. 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.

  17. The minimal leak test technique for endotracheal cuff maintenance.

    PubMed

    Harvie, D A; Darvall, J N; Dodd, M; De La Cruz, A; Tacey, M; D'Costa, R L; Ward, D

    2016-09-01

    Endotracheal tube (ETT) cuff pressure management is an essential part of airway management in intubated and mechanically ventilated patients. Both under- and over-inflation of the ETT cuff can lead to patient complications, with an ideal pressure range of 20-30 cmH2O defined. A range of techniques are employed to ensure adequate ETT cuff inflation, with little comparative data. We performed an observational cross-sectional study in a tertiary metropolitan ICU, assessing the relationship between the minimal leak test and cuff manometry. Forty-five mechanically ventilated patients, over a three-month period, had ETT cuff manometry performed at the same time as their routine cuff maintenance (minimal leak test). Bedside nurse measurements were compared with investigator measurements. At the endpoint of cuff inflation, 20 of 45 patients (44%) had cuff pressures between 20 and 30 cmH2O; 11 of 45 patients (24%) had cuff pressures <20 cmH2O; 14 of 45 patients (31%) had cuff pressures ≥30 cmH2O. Univariate analysis demonstrated an association between both patient obesity and female gender requiring less ETT cuff volume (P=0.008 and P <0.001 respectively), though this association was lost on multivariate analysis. No association was demonstrated between any measured variables and cuff pressures. Inter-operator reliability in performing the minimal leak test showed no evidence of bias between nurse and investigators (Pearson coefficient = 0.897). We conclude the minimal leak test for maintenance of ETT cuffs leads to both over- and under-inflation, and alternative techniques, such as cuff manometry, should be employed.

  18. Leak detection, monitoring, and mitigation technology trade study update

    SciTech Connect

    HERTZEL, J.S.

    1998-11-10

    This document is a revision and update to the initial report that describes various leak detection, monitoring, and mitigation (LDMM) technologies that can be used to support the retrieval of waste from the single-shell tanks (SST) at the Hanford Site. This revision focuses on the improvements in the technical performance of previously identified and useful technologies, and it introduces new technologies that might prove to be useful.

  19. Pathogenesis of vascular leak in dengue virus infection.

    PubMed

    Malavige, Gathsaurie Neelika; Ogg, Graham S

    2017-07-01

    Endothelial dysfunction leading to vascular leak is the hallmark of severe dengue. Vascular leak typically becomes clinically evident 3-6 days after the onset of illness, which is known as the critical phase. This critical phase follows the period of peak viraemia, and lasts for 24-48 hr and usually shows rapid and complete reversal, suggesting that it is likely to occur as a result of inflammatory mediators, rather than infection of the endothelium. Cytokines such as tumour necrosis factor-α, which are known to be elevated in the critical phase of dengue, are likely to be contributing factors. Dengue NS1, a soluble viral protein, has also been shown to disrupt the endothelial glycocalyx and thus contribute to vascular leak, although there appears to be a discordance between the timing of NS1 antigenaemia and occurrence of vascular leak. In addition, many inflammatory lipid mediators are elevated in acute dengue viral infection such as platelet activating factor (PAF) and leukotrienes. Furthermore, many other inflammatory mediators such as vascular endothelial growth factor and angiopoietin-2 have been shown to be elevated in patients with dengue haemorrhagic fever, exerting their action in part by inducing the activity of phospholipases, which have diverse inflammatory effects including generation of PAF. Platelets have also been shown to significantly contribute to endothelial dysfunction by production of interleukin-1β through activation of the NLRP3 inflammasome and also by inducing production of inflammatory cytokines by monocytes. Drugs that block down-stream immunological mediator pathways such as PAF may also be beneficial in the treatment of severe disease. © 2017 John Wiley & Sons Ltd.

  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 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.

  1. 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.

  2. 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.

  3. 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.

  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. -- 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Optimization of the leak conductance in the squid giant axon.

    PubMed

    Seely, Jeffrey; Crotty, Patrick

    2010-08-01

    We report on a theoretical study showing that the leak conductance density, G{L} , in the squid giant axon appears to be optimal for the action potential firing frequency. More precisely, the standard assumption that the leak current is composed of chloride ions leads to the result that the experimental value for G{L} is very close to the optimal value in the Hodgkin-Huxley model, which minimizes the absolute refractory period of the action potential, thereby maximizing the maximum firing frequency under stimulation by sharp, brief input current spikes to one end of the axon. The measured value of G{L} also appears to be close to optimal for the frequency of repetitive firing caused by a constant current input to one end of the axon, especially when temperature variations are taken into account. If, by contrast, the leak current is assumed to be composed of separate voltage-independent sodium and potassium currents, then these optimizations are not observed.

  13. 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.

  14. Are Optical Gas Imaging Technologies Effective For Methane Leak Detection?

    PubMed

    Ravikumar, Arvind P; Wang, Jingfan; Brandt, Adam R

    2017-01-03

    Concerns over mitigating methane leakage from the natural gas system have become ever more prominent in recent years. Recently, the U.S. Environmental Protection Agency proposed regulations requiring use of optical gas imaging (OGI) technologies to identify and repair leaks. In this work, we develop an open-source predictive model to accurately simulate the most common OGI technology, passive infrared (IR) imaging. The model accurately reproduces IR images of controlled methane release field experiments as well as reported minimum detection limits. We show that imaging distance is the most important parameter affecting IR detection effectiveness. In a simulated well-site, over 80% of emissions can be detected from an imaging distance of 10 m. Also, the presence of "superemitters" greatly enhance the effectiveness of IR leak detection. The minimum detectable limits of this technology can be used to selectively target "superemitters", thereby providing a method for approximate leak-rate quantification. In addition, model results show that imaging backdrop controls IR imaging effectiveness: land-based detection against sky or low-emissivity backgrounds have higher detection efficiency compared to aerial measurements. Finally, we show that minimum IR detection thresholds can be significantly lower for gas compositions that include a significant fraction nonmethane hydrocarbons.

  15. 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.

  16. 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.

  17. 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.

  18. Endoscopic management of gastrointestinal perforations, leaks and fistulas

    PubMed Central

    Rogalski, Pawel; Daniluk, Jaroslaw; Baniukiewicz, Andrzej; Wroblewski, Eugeniusz; Dabrowski, Andrzej

    2015-01-01

    Gastrointestinal perforations, leaks and fistulas may be serious and life-threatening. The increasing number of endoscopic procedures with a high risk of perforation and the increasing incidence of leakage associated with bariatric operations call for a minimally invasive treatment for these complications. The therapeutic approach can vary greatly depending on the size, location, and timing of gastrointestinal wall defect recognition. Some asymptomatic patients can be treated conservatively, while patients with septic symptoms or cardio-pulmonary insufficiency may require intensive care and urgent surgical treatment. However, most gastrointestinal wall defects can be satisfactorily treated by endoscopy. Although the initial endoscopic closure rates of chronic fistulas is very high, the long-term results of these treatments remain a clinical problem. The efficacy of endoscopic therapy depends on several factors and the best mode of treatment will depend on a precise localization of the site, the extent of the leak and the endoscopic appearance of the lesion. Many endoscopic tools for effective closure of gastrointestinal wall defects are currently available. In this review, we summarized the basic principles of the management of acute iatrogenic perforations, as well as of postoperative leaks and chronic fistulas of the gastrointestinal tract. We also described the effectiveness of various endoscopic methods based on current research and our experience. PMID:26457014

  19. 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.

  20. 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.