WorldWideScience

Sample records for volumetric leak detection

  1. Aspects of leak detection

    Energy Technology Data Exchange (ETDEWEB)

    Chivers, T.C. [Berkeley Technology Centre, Glos (United Kingdom)

    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.

  2. Leak detection/verification

    Energy Technology Data Exchange (ETDEWEB)

    Krhounek, V.; Zdarek, J.; Pecinka, L. [Nuclear Research Institute, Rez (Czech Republic)

    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.

  3. Sensors for Fluid Leak Detection

    Directory of Open Access Journals (Sweden)

    Gonzalo Pajares Martinsanz

    2015-02-01

    Full Text Available Fluid leak detection represents a problem that has attracted the interest of researchers, but not exclusively because in industries and services leaks are frequently common. Indeed, in water or gas supplies, chemical or thermal plants, sea-lines or cooling/heating systems leakage rates can cause important economic losses and sometimes, what it is more relevant, environmental pollution with human, animal or plant lives at risk. This last issue has led to increased national and international regulations with different degrees of severity regarding environmental conservation.[...

  4. Leak detection capability in CANDU reactors

    Energy Technology Data Exchange (ETDEWEB)

    Azer, N.; Barber, D.H.; Boucher, P.J. [and others

    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.

  5. Recent Progress in Technology of Leak detection

    Energy Technology Data Exchange (ETDEWEB)

    Jung, H. K.; Kim, S. H.; Cho, J. W.; Joo, Y. S.; Yang, D. J

    2005-07-15

    It is very important to check for leakage points of fluids and gases on primary pressure boundary of nuclear power plants in order to maintain and manage various structures safely. Even though much investigation has been performed by a number of researchers, there are a lot of problems to detect the leakage under some areas to which people can not approach. In particular, it is certainly necessary to find the leakage point in order to repair and replace the pressure boundaries. In this report, the basic principle and application situations for the development of the leak detection system which can detect micro-leaks are introduced. As the technologies and performances of recent sensors have been improving, the application range of leak detection has been increasing steadily. Therefore the sensor technologies written in this report will be able to contribute to nuclear safety to detect the leakage rate and the leakage point with an on-line monitoring system in the near future.

  6. Leak detection in pipelines using cepstrum analysis

    Science.gov (United States)

    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.

  7. Hydrocarbon Leak Detection Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — FTT is proposing the development of a sensor to detect the presence of hydrocarbons in turbopump Inter-Propellant Seals (IPS). The purpose of the IPS is to prevent...

  8. 49 CFR 195.134 - CPM leak detection.

    Science.gov (United States)

    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...

  9. 49 CFR 195.444 - CPM leak detection.

    Science.gov (United States)

    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...

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

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, S.; Ghadiali, N.; Paul, D.; Wilkowski, G. [Battelle, Columbus, OH (United States)

    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.

  11. Leak Detection in Offshore Pipelines of Conveying Fluid

    Institute of Scientific and Technical Information of China (English)

    李俊花; 崔莉

    2004-01-01

    Leakage from pipelines has caused serious environmental pollution and economic losses. Usually, leak detection can reduce the damage. The paper mainly discusses a hydraulic gradient-based leak detection method. The basic idea is outlined first, followed by a description of a laboratory experiment in a water pipeline. Several pressure curves are established based on different leak locations under the condition of a constant total flow rate. It is demonstrated that the leak of a large leak quantity can be detected reliably by the hydraulic gradient method.

  12. Detection of interstate liquids pipeline leaks: Feasibility evaluation

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. 241-AY-102 Leak Detection Pit Drain Line Inspection Report

    Energy Technology Data Exchange (ETDEWEB)

    Boomer, Kayle D. [Washington River Protection Solutions, LLC (United States); Engeman, Jason K. [Washington River Protection Solutions, LLC (United States); Gunter, Jason R. [Washington River Protection Solutions, LLC (United States); Joslyn, Cameron C. [Washington River Protection Solutions, LLC (United States); Vazquez, Brandon J. [Washington River Protection Solutions, LLC (United States); Venetz, Theodore J. [Washington River Protection Solutions, LLC (United States); Garfield, John S. [AEM Consulting (United States)

    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.

  16. Active acoustic leak detection for LMFBR steam generators. Pt. 7. Potential for small leak detection

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, Hiromichi; Yoshida, Kazuo [Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan). Komae Research Lab.

    1998-05-01

    In order to prevent the expansion of tube damage and to maintain structural integrity in the steam generators (SGs) of fast breeder reactors (FBR), it is necessary to detect precisely and immediately the leakage of water from heat transfer tubes. Therefore, an active acoustic method, which detects the sound attenuation due to bubbles generated in the sodium-water reactions, is being developed. Previous studies have revealed that the active acoustic method can detect bubbles of 10 l/s (equivalence water leak rate about 10 g/s) within 10 seconds in practical steam generators. In order to prevent the expansion of damage to neighboring tubes, however, it is necessary to detect smaller leakage of water from heat transfer tubes. In this study, in order to evaluate the detection sensitivity of the active method, the signal processing methods for emitter and receiver sound and the detection method for leakage within 1 g/s are investigated experimentally, using an SG full-sector model that simulates the actual SGs. A typical result shows that detection of 0.4 l/s air bubbles (equivalent water leak rate about 0.4 g/s) takes about 80 seconds, which is shorter than the propagation time of damage to neighboring tubes. (author)

  17. Acoustic valve leak detection: Initial program development, implementation & experience

    Energy Technology Data Exchange (ETDEWEB)

    Wicker, G.L. [Baltimore Gas and Electric Company, Baltimore, MD (United States)

    1996-07-01

    Acoustic valve leak detection is one of the many test techniques employed in modern power plants with active predictive maintenance programs. In 1994, a valve leak detection program was implemented within Baltimore Gas and Electric`s Fossil Energy Division. Within two years, the program resulted in energy savings in excess of one million dollars. The leak detection program has become an essential technology that has reduced plant heat rate losses, prevented unnecessary valve maintenance and increased plant awareness of potential losses. This paper describes program development, implementation and test methodology of Baltimore Gas and Electric`s acoustic leak detection program. Key topics include equipment description, program measurements, methodology and leak identification methods. The paper also will include discussion on the practical approach of equipment selection and program philosophies.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. ISS Ammonia Leak Detection Through X-Ray Fluorescence

    Science.gov (United States)

    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. Detecting gas leaks by ultrasonic emission

    DEFF Research Database (Denmark)

    Rasmussen, Karsten Bo; Henriksen, Eigil

    1997-01-01

    The emission of noise in the frequency range 10 kHz to 25.6 kHz from an experimental gas leak in a flanged joint has been experimentally investigated. The overall conclusion is that the emitted noise is almost frequency independent in level within the considered frequency range.A small PC program...

  1. Distributed Leak Detection System Using Structure-Borne Noise Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Manned spacecraft are vulnerable to air leaks caused by micrometeorite and space debris impact. The ability to detect and quickly locate and mitigate a pressure...

  2. Distributed Leak Detection System Using Structure-Borne Noise Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Manned spacecraft are vulnerable to air leaks caused by micrometeoroid and space debris impact. The ability to detect and quickly locate and mitigate a pressure...

  3. [External lumbar drainage with volumetric continuing infusion pump in patients with cerebrospinal fluid leak. A case series].

    Science.gov (United States)

    Manso Melgosa, Ana Belén; García Gutiérrez, Helena; Fernández Porras, Mónica; Castrillo Manero, Ana Berta; Pérez Marijuán, Belén

    To describe the incidence and complications arising in a number of cases of patients with cerebrospinal fluid leak treated by external lumbar drainage with infusion pump (IP) volumetric continuous from 2001 to 2014. Quantify cerebrospinal fluid leak closed by lumbar drainage with IP. Retrospective descriptive case series study. patients undergoing transsphenoidal pituitary surgery, Chiari surgery and laminectomy, that developed postoperative cerebrospinal fluid leak treated with continuous external lumbar drainage by IP. age, sex, type of intervention, variables related to the practice of the pump and complications. Average and medians were calculated for quantitative variables, frequencies and percentages for qualitative. Sample: 11 subjects. Incidence in running IP: disconnection, occlusion and acoustic alarm activation. Most frequently complication is headache; a case of pneumocephalus. The small number of subjects and the heterogeneity of these do not allow for comparison or establishing associations between variables. The resolution of the cerebrospinal fluid leak with continuous IP is lower in this study than others, and may be influenced by the small number of subjects. It should be noted the frequent activation of the pump alarm for no apparent cause. Protocol would be developed for preparing the IP team to reduce the acoustic alarm activation, and would make a prospective multicenter study. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  4. Local Leak Detection and Health Monitoring of Pressurized Tanks

    Science.gov (United States)

    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.

  5. Color Changing Material for Hydrogen Leak Detection

    Science.gov (United States)

    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.

  6. Imaging spectrometer for fugitive gas leak detection

    Science.gov (United States)

    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.

  7. 340 Facility secondary containment and leak detection

    Energy Technology Data Exchange (ETDEWEB)

    Bendixsen, R.B.

    1995-01-31

    This document presents a preliminary safety evaluation for the 340 Facility Secondary Containment and Leak Containment system, Project W-302. Project W-302 will construct Building 340-C which has been designed to replace the current 340 Building and vault tank system for collection of liquid wastes from the Pacific Northwest Laboratory buildings in the 300 Area. This new nuclear facility is Hazard Category 3. The vault tank and related monitoring and control equipment are Safety Class 2 with the remainder of the structure, systems and components as Safety Class 3 or 4.

  8. High Altitude Aerial Natural Gas Leak Detection System

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

  10. Leak detection utilizing analog binaural (VLSI) techniques

    Science.gov (United States)

    Hartley, Frank T. (Inventor)

    1995-01-01

    A detection method and system utilizing silicon models of the traveling wave structure of the human cochlea to spatially and temporally locate a specific sound source in the presence of high noise pandemonium. The detection system combines two-dimensional stereausis representations, which are output by at least three VLSI binaural hearing chips, to generate a three-dimensional stereausis representation including both binaural and spectral information which is then used to locate the sound source.

  11. Methane Leak Detection and Emissions Quantification with UAVs

    Science.gov (United States)

    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.

  12. Towards aerial natural gas leak detection system based on TDLAS

    Science.gov (United States)

    Liu, Shuyang; Zhou, Tao; Jia, Xiaodong

    2014-11-01

    Pipeline leakage is a complex scenario for sensing system due to the traditional high cost, low efficient and labor intensive detection scheme. TDLAS has been widely accepted as industrial trace gas detection method and, thanks to its high accuracy and reasonable size, it has the potential to meet pipeline gas leakage detection requirements if it combines with the aerial platform. Based on literature study, this paper discussed the possibility of applying aerial TDLAS principle in pipeline gas leak detection and the key technical foundation of implementing it. Such system is able to result in a high efficiency and accuracy measurement which will provide sufficient data in time for the pipeline leakage detection.

  13. Safe Detection System for Hydrogen Leaks

    Energy Technology Data Exchange (ETDEWEB)

    Lieberman, Robert A. [Intelligent Optical Systems, Inc., Torrance, CA (United States); Beshay, Manal [Intelligent Optical Systems, Inc., Torrance, CA (United States)

    2012-02-29

    Hydrogen is an "environmentally friendly" fuel for future transportation and other applications, since it produces only pure ("distilled") water when it is consumed. Thus, hydrogen-powered vehicles are beginning to proliferate, with the total number of such vehicles expected to rise to nearly 100,000 within the next few years. However, hydrogen is also an odorless, colorless, highly flammable gas. Because of this, there is an important need for hydrogen safety monitors that can warn of hazardous conditions in vehicles, storage facilities, and hydrogen production plants. To address this need, IOS has developed a unique intrinsically safe optical hydrogen sensing technology, and has embodied it in detector systems specifically developed for safety applications. The challenge of using light to detect a colorless substance was met by creating chemically-sensitized optical materials whose color changes in the presence of hydrogen. This reversible reaction provides a sensitive, reliable, way of detecting hydrogen and measuring its concentration using light from low-cost LEDs. Hydrogen sensors based on this material were developed in three completely different optical formats: point sensors ("optrodes"), integrated optic sensors ("optical chips"), and optical fibers ("distributed sensors") whose entire length responds to hydrogen. After comparing performance, cost, time-to-market, and relative market need for these sensor types, the project focused on designing a compact optrode-based single-point hydrogen safety monitor. The project ended with the fabrication of fifteen prototype units, and the selection of two specific markets: fuel cell enclosure monitoring, and refueling/storage safety. Final testing and development of control software for these markets await future support.

  14. Optoelectronic leak detection system for monitoring subsea structures

    Science.gov (United States)

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

    2010-04-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

  17. PRACTICAL IMPLICATIONS OF USING INDUCED TRANSIENTS FOR LEAK DETECTION

    Directory of Open Access Journals (Sweden)

    Marko V. Ivetic

    2007-01-01

    Full Text Available This paper deals with practical problems of leak detection by methods based on hydraulic transient analysis. Controlled and safe transients can be generated and the response of the network, with the relevant information, can be monitored and analysed. Information about leaks, contained in the monitored pressure signal, cannot be easily retrieved, due to reflections, noise etc. On the basis of numerical experiments on a simple network, merits and limitations of several methods for signal analysis (time domain analysis, spectral density function and wavelet transform have been examined. Certain amount of information can be extracted from the time history of the pressure signal, assuming the first reflection of the pressure wave is captured with very high time resolution and accuracy. Only relatively large leaks can be detected using this methodology. As a way to increase the sensitivity of this method it is suggested that transforms in frequency domain and, especially, wavelet transforms, are used. The most promising method for leakage location and quantification seems to be based on wavelet analysis.

  18. PRACTICAL IMPLICATIONS OF USING INDUCED TRANSIENTS FOR LEAK DETECTION

    Directory of Open Access Journals (Sweden)

    Marko V. Ivetic

    2007-06-01

    Full Text Available This paper deals with practical problems of leak detection by methods based on hydraulic transient analysis. Controlled and safe transients can be generated and the response of the network, with the relevant information, can be monitored and analysed. Information about leaks, contained in the monitored pressure signal, cannot be easily retrieved, due to reflections, noise etc. On the basis of numerical experiments on a simple network, merits and limitations of several methods for signal analysis (time domain analysis, spectral density function and wavelet transform have been examined. Certain amount of information can be extracted from the time history of the pressure signal, assuming the first reflection of the pressure wave is captured with very high time resolution and accuracy. Only relatively large leaks can be detected using this methodology. As a way to increase the sensitivity of this method it is suggested that transforms in frequency domain and, especially, wavelet transforms, are used. The most promising method for leakage location and quantification seems to be based on wavelet analysis.

  19. Leak detection and localization system through acoustics; Sistema de deteccao e localizacao de vazamentos por acustica

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, Julio [Aselco Automacao, Sao Paulo, SP (Brazil)

    2003-07-01

    Acoustic Leak Detection Systems (ALDS) are used on both liquid and gas pipelines as well as multi-phase flow pipelines to detect leaks quickly and provide a means of limiting product loss. The real-time acoustic signal is continuously compared against signature leak profiles for the particular operating and geometric conditions. These profiles were developed from a database established from over 20 years of experimental and field leak tests. This technique not only drastically reduces the false alarm rate, but also significantly improves the sensitivity and leak location accuracy. This system will also detect leaks with shut-in flow (zero flow rate in the pipeline). With the use of GPS (Global Positioning System) it not only improves leak location accuracy, but also allows for continuous leak detection during the loss of communications. (author)

  20. Passive Leak Detection Using Commercial Hydrogen Colorimetric Indicator

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, Kevin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Buttner, William [National Renewable Energy Lab. (NREL), Golden, CO (United States); Burgess, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States); Rivkin, Carl [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    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.

  1. System for Steam Leak Detection by using CCTV Camera

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Young Chul; Lee, Min Soo; Choi, Hui Ju [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Son, Ki Sung; Jeon, Hyeong Seop [SAEAN.Co., Seoul (Korea, Republic of)

    2012-05-15

    There are many pipes in the secondary cooling systems of nuclear power plants and coal-fired power plants. In these pipes, high pressure fluids are moving with at high velocity, which can cause steam leakage due to pipe thinning. Steam leakage is one of the major issues for the structural fracture of pipes. Therefore, a method to inspect a large area of piping systems quickly and accurately is needed. Steam leakage is almost invisible, because the flow has very high velocity and pressure. Therefore, it is very difficult to detect a steam leakage. In this paper, we proposed the method for detecting steam leakage using image signal processing. Our basic idea comes from a heat shimmer, which shines with a soft light that looks as if it is being shaken slightly. To test the performance of this technique, experiments have been performed for a steam generator. Results show that the proposed technique is quite powerful for steam leak detection

  2. Corrosion Evaluation of Tank 40 Leak Detection Box

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J.I.

    1999-07-29

    'Leak detection from the transfer lines in the tank farm has been a concern for many years because of the need to minimize exposure of personnel and contamination of the environment. The leak detection box (LDB) is one line of defense, which must be maintained to meet this objective. The evaluation of a failed LDB was one item from an action plan aimed at minimizing the degradation of LDBs. The Tank 40 LDB, which failed in service, was dug up and shipped to SRTC for evaluation. During a video inspection while in service, this LDB was found to have black tubercles on the interior, which suggested possible microbial involvement. The failure point, however, was believed to have occurred in the drain line from the transfer line jacket. Visual, metallurgical, and biological analyses were performed on the LDB. The analysis results showed that there was not any adverse microbiological growth or significant localized corrosion. The corrosion of the LDB was caused by exposure to aqueous environments and was typical of carbon steel pipes in soil environments.'

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

    Science.gov (United States)

    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.

  4. Detection of leaks in buried rural water pipelines using thermal infrared images

    Science.gov (United States)

    Eidenshink, Jeffery C.

    1985-01-01

    Leakage is a major problem in many pipelines. Minor leaks called 'seeper leaks', which generally range from 2 to 10 m3 per day, are common and are difficult to detect using conventional ground surveys. The objective of this research was to determine whether airborne thermal-infrared remote sensing could be used in detecting leaks and monitoring rural water pipelines. This study indicates that such leaks can be detected using low-altitude 8.7- to 11.5. micrometer wavelength, thermal infrared images collected under proper conditions.

  5. Mobile Sensor Networks for Leak and Backflow Detection in Water Distribution Systems

    KAUST Repository

    Suresh, M. Agumbe

    2014-05-01

    Leak and backflow detection are essential aspects of Water Distribution System (WDS) monitoring. Most existing solutions for leak/backflow detection in WDSs focus on the placement of expensive static sensors located strategically. In contrast to these, we propose a solution whereby mobile sensors (i.e., their movement aided only by the inherent water flow in the system) detect leaks/backflow. Information about the leaks/backflow is collected from the sensors either by physically capturing them, or through wireless communication. Specifically, we propose models to maximize leak/backflow detection given a cost constraint (a limit on the number of sensors). Through extensive simulations, we demonstrate the superior performance of our proposed solution when compared with the state of the art solutions (e.g., algorithms/protocols and analysis).

  6. Leak Detection and H2 Sensor Development for Hydrogen Applications

    Energy Technology Data Exchange (ETDEWEB)

    Brosha, Eric L. [Los Alamos National Laboratory

    2012-07-10

    The objectives of this report are: (1) Develop a low cost, low power, durable, and reliable hydrogen safety sensor for a wide range of vehicle and infrastructure applications; (2) Continually advance test prototypes guided by materials selection, sensor design, electrochemical R&D investigation, fabrication, and rigorous life testing; (3) Disseminate packaged sensor prototypes and control systems to DOE Laboratories and commercial parties interested in testing and fielding advanced prototypes for cross-validation; (4) Evaluate manufacturing approaches for commercialization; and (5) Engage an industrial partner and execute technology transfer. Recent developments in the search for sustainable and renewable energy coupled with the advancements in fuel cell powered vehicles (FCVs) have augmented the demand for hydrogen safety sensors. There are several sensor technologies that have been developed to detect hydrogen, including deployed systems to detect leaks in manned space systems and hydrogen safety sensors for laboratory and industrial usage. Among the several sensing methods electrochemical devices that utilize high temperature-based ceramic electrolytes are largely unaffected by changes in humidity and are more resilient to electrode or electrolyte poisoning. The desired sensing technique should meet a detection threshold of 1% (10,000 ppm) H{sub 2} and response time of {approx_equal}1 min, which is a target for infrastructure and vehicular uses. Further, a review of electrochemical hydrogen sensors by Korotcenkov et.al and the report by Glass et.al suggest the need for inexpensive, low power, and compact sensors with long-term stability, minimal cross-sensitivity, and fast response. This view has been largely validated and supported by the fuel cell and hydrogen infrastructure industries by the NREL/DOE Hydrogen Sensor Workshop held on June 8, 2011. Many of the issues preventing widespread adoption of best-available hydrogen sensing technologies available today

  7. Leak Detection Modeling and Simulation for Oil Pipeline with Artificial Intelligence Method

    Directory of Open Access Journals (Sweden)

    Pudjo Sukarno

    2007-05-01

    Full Text Available Leak detection is always interesting research topic, where leak location and leak rate are two pipeline leaking parameters that should be determined accurately to overcome pipe leaking problems. In this research those two parameters are investigated by developing transmission pipeline model and the leak detection model which is developed using Artificial Neural Network. The mathematical approach needs actual leak data to train the leak detection model, however such data could not be obtained from oil fields. Therefore, for training purposes hypothetical data are developed using the transmission pipeline model, by applying various physical configuration of pipeline and applying oil properties correlations to estimate the value of oil density and viscosity. The various leak locations and leak rates are also represented in this model. The prediction of those two leak parameters will be completed until the total error is less than certain value of tolerance, or until iterations level is reached. To recognize the pattern, forward procedure is conducted. The application of this approach produces conclusion that for certain pipeline network configuration, the higher number of iterations will produce accurate result. The number of iterations depend on the leakage rate, the smaller leakage rate, the higher number of iterations are required. The accuracy of this approach is clearly determined by the quality of training data. Therefore, in the preparation of training data the results of pressure drop calculations should be validated by the real measurement of pressure drop along the pipeline. For the accuracy purposes, there are possibility to change the pressure drop and fluid properties correlations, to get the better results. The results of this research are expected to give real contribution for giving an early detection of oil-spill in oil fields.

  8. Doppler method leak detection for LMFBR steam generators. Pt. 3. Investigation of detection sensitivity and method

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, Hiromichi; Kinoshita, Izumi [Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan). Komae Research Lab

    2001-04-01

    To prevent the expansion of tube damage and to maintain structural integrity in the steam generators (SGs) of a fast breeder reactor (FBR), it is necessary to detect precisely and immediately any leakage of water from heat transfer tubes. Therefore, the Doppler method was developed. Previous studies have revealed that, in the SG full-sector model that simulates actual SGs, the Doppler method can detect bubbles of 0.4 l/s within a few seconds. However in consideration of the dissolution rate of hydrogen generated by a sodium-water reaction even from a small water leak, it is necessary to detect smaller leakages of water from the heat transfer tubes. The detection sensitivity of the Doppler method and the influence of background noise were experimentally investigated. In-water experiments were performed using the SG model. The results show that the Doppler method can detect bubbles of 0.01 l/s (equivalent to a water leak rate of about 0.01 g/s) within a few seconds and that the background noise has little effect on water leak detection performance. The Doppler method thus has great potential for the detection of water leakage in SGs. (author)

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

    Science.gov (United States)

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

    1995-01-01

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

  10. Detection of bile duct leaks using MR cholangiography with mangfodipir trisodium (Teslascan).

    Science.gov (United States)

    Vitellas, K M; El-Dieb, A; Vaswani, K; Bennett, W F; Fromkes, J; Steinberg, S; Bova, J G

    2001-01-01

    Mangafodipir trisodium (Teslascan), a hepatobiliary contrast agent, has the potential of providing functional biliary imaging similar to hepatobiliary scintigraphy. To our knowledge. the potential role of this biliary contrast agent in the detection of bile duct leaks has not been reported. In this case report, we report the first case of a bile duct leak diagnosed with enhanced MRI with mangafodipir trisodium in a patient following laparoscopic cholecystectomy. Our case illustrates that functional MR cholangiography images can be successfully acquired by using a post-mangafodipir fat-suppressed GRE technique and that bile duct leaks can be detected.

  11. Using Decision Trees to Detect and Isolate Leaks in the J-2X

    Data.gov (United States)

    National Aeronautics and Space Administration — Full title: Using Decision Trees to Detect and Isolate Simulated Leaks in the J-2X Rocket Engine Mark Schwabacher, NASA Ames Research Center Robert Aguilar, Pratt...

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

    Science.gov (United States)

    Zhao, Ling; Yang, Hongjiu

    2017-03-01

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

  13. Development of microphone leak detection technology in Fugen Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Shimanskiy, Sergey; Iijima, Takashi; Naoi, Yosuke [Japan Nuclear Cycle Development Inst., Fugen Nuclear Power Station, Tsuruga, Fukui (Japan)

    2002-06-01

    A method of leak detection, based on high-temperature resistant microphones, was originally developed in JNC to detect leakages with flow rates from 1 m{sup 3}/h to 500 m{sup 3}/h. The development performed in Fugen and reported here focuses on detection of a small leakage at an early stage by the same microphone method. Specifically, for the inlet feeder pipes the leak rate of 0.2 gpm (0.046 m{sup 3}/h) has been chosen as the target detection capability. Evaluation of detection sensitivity and leak localization accuracy was conducted based on various analysis methods in order to check the capability of the method to satisfy this requirement. The possibility of detecting and locating a small leakage has been demonstrated through the research. The probabilistic detection algorithm and multi-channel location-based detection are proposed in order to improve both the detection sensitivity and the localization accuracy. (author)

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

    Science.gov (United States)

    Mather, Janice L.; Taylor, Shawn C.

    2015-01-01

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

  15. ANALYSIS OF FIRST TRANSIENT PRESSURE OSCILLATION FOR LEAK DETECTION IN A SINGLE PIPELINE

    Institute of Scientific and Technical Information of China (English)

    GUO Xin-lei; YANG Kai-lin; LI Fu-tian; WANG Tao; FU hui

    2012-01-01

    The leak detection is of great importance in the reliable operation and management of a pipeline system.Recently,attention is shifted to the use of the time domain or frequency domain methods based on the transient analysis.These methods sometimes require accurate pressure signals obtained during the transient period or by creating ideal conditions in testing.This paper proposes a method that does not require transient simulations over the whole or an extended period of time,but uses the first transient pressure oscillation to detect leaks.The method considers the propagation of the pressure oscillation wave created from a tast valve closure and the reflected damp wave from the leak.A leak in the pipe gives rise to reflected waves which in turn create discontinuities in the observed signal at the measurement section.The timing of the reflected damp wave and the magnitude represent the location and the size of the leak,respectively.An analytical expression is derived based on the Method Of Characteristic (MOC) for the relationship between the leakage and the reflected magnitude.The leak detection procedure based on the method is also given.Then the reliability of the method is tested on numerically simulated pressure signals and experimental pressure signals with calibrated leak parameters,and the results indicate a successful application and the promising features of the method.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-03-01

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

  17. AIRBORNE, OPTICAL REMOTE SENSNG OF METHANE AND ETHANE FOR NATURAL GAS PIPELINE LEAK DETECTION

    Energy Technology Data Exchange (ETDEWEB)

    Jerry Myers

    2005-04-15

    Ophir Corporation was awarded a contract by the U. S. Department of Energy, National Energy Technology Laboratory under the Project Title ''Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipeline Leak Detection'' on October 14, 2002. The scope of the work involved designing and developing an airborne, optical remote sensor capable of sensing methane and, if possible, ethane for the detection of natural gas pipeline leaks. Flight testing using a custom dual wavelength, high power fiber amplifier was initiated in February 2005. Ophir successfully demonstrated the airborne system, showing that it was capable of discerning small amounts of methane from a simulated pipeline leak. Leak rates as low as 150 standard cubic feet per hour (scf/h) were detected by the airborne sensor.

  18. Analytical study of the performance of a geomembrane leak detection system.

    Science.gov (United States)

    Lugli, Francesco; Mahler, Claudio Fernando

    2016-05-01

    The electrical detection of leaks in geomembranes is a method that allows identifying leakage of contaminants in lined facilities (e.g. sanitary landfills, pollutant ponds, etc.). The procedure in the field involves placing electrodes above and below the geomembrane, to generate an electrical current, which in turn engenders an electric potential distribution in the protective layer (generally a clayey soil). The electric potential will be greater in areas with higher current density, i.e. near leaks. In this study, we combined models from the literature to carry out a parametric analysis to identify the variables that most influence the amplitude of the electrical signals produced by leaks. The basic hypothesis is that the electrical conduction phenomena in a liner system could be depicted by a direct current circuit. After determining the value of the current at the leak, we calculated the electric potential distribution according to the model of Darilek and Laine. This enabled analysing the sensitivity of the parameters, which can be useful in the design of landfills and facilitate the location of leaks. This study showed that geomembranes with low electrical resistance (owing to low thickness, low resistivity, or extensive area) can hinder the leak detection process. In contrast, low thickness and high resistivity of the protection layer magnify the leak signal.

  19. Detection and Prevention of Sensitive Data From Data Leak Using Shingling and Rabin Filter

    Directory of Open Access Journals (Sweden)

    Sushma Vishwanath Gaikwad

    2016-10-01

    Full Text Available Data leak is a major problem in all the organization of any land. A deliberate risk to institution and private security is the disclosure of secure data in transmission and storage. To check content for exposed sensitive data is the main aim for exposed sensitive data. There are large numbers of data-leak cases but human flaws are one of the main reasons of data leak. This paper proposed a data-leak detection model for preventing accidental and intentional data leak in network. If someone succeed to steal some kind of data and send that data to outsider then data owner has obtain to use two methods to find out guilty employee or leaker. This work suggests use of shingling and rabin filter system performs Data Leak Detection (DLD and Prevention task. The results show that this approach can be effectively implemented in various organizations; however rigorous testing on various data division of such methods will be required to implement the same in sector of importance like defence and other even in large establishment. Keywords—  Information security; Data leak; network security; privacy.

  20. Technical basis for inner container leak detection sensitivity goals in 3013 DE surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Berg, John M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-11

    Helium leak checking of 3013 inner container lids is under consideration for addition to DE Surveillance tasks as an improved means to detect any through-wall flaws that may have formed during storage. This white paper evaluates whether leak checking at DE could replace and improve upon the current method of comparing gas compositions and pressures within the inner and outer containers. We have used viscous and molecular flow equations in ANSI N14.5 to calculate what the measured standard helium leak rate would be for hypothetical leaks of three different sizes. For comparison, we have also calculated the effects on gas composition and pressure differences as a function of pre-DE storage time for the same three leak sizes, using molecular and viscous flow equations as well as diffusion equations to predict the relevant gas transport. For a hypothetical leak that would be measured at 1x10-7 std cc/sec, likely an achievable sensitivity using helium leak checking at DE, the calculations predict no measurable effect on pressure difference or gas composition as measured by DE gas analysis. We also calculate that it would take over 200 years for water vapor to diffuse through a 10-7 std cc/sec leak enough to raise the RH outer container to half the RH value in the inner container. A leak 100 times larger, which would be measured at 1x10-5 std cc/sec, the same water vapor diffusion would take at least 14 years. Our conclusion is that helium leak checking will be useful even at a sensitivity of 1x10-5 std cc/sec, and a significant improvement over current DE methods at a sensitivity of 1x10-7 std cc/sec.

  1. Spontaneous Intracranial Hypotension With Site of Leak Detected Only After 111In-DTPA Cisternogram.

    Science.gov (United States)

    Parsian, Sana; Matesan, Manuela C; Kumbhar, Sachin Shivaji; Lewis, David H

    2017-04-01

    A 54-year-old man with a 3-week history of orthostatic headache and acute on chronic subdural hematoma presented with imaging findings suggestive of spontaneous intracranial hypotension. Three myelograms were negative for leak, and nontargeted epidural blood patches did not result in symptom relief. A cerebrospinal fluid leak study using In-DTPA with SPECT/CT demonstrated a focal area of asymmetric activity at the left C2 nerve root. A left C2 root tie-off, targeted epidural blood patch, and Dura seal glue resulted in resolution of patient symptomatology highlighting the importance of fused SPECT/CT images in detection of an occult cerebral spinal fluid leak.

  2. The CMEKF Method for Sub-Sea Pipeline Monitoring and Leak Detection

    Institute of Scientific and Technical Information of China (English)

    白莉; 岳前进; 崔莉; 李洪升; 金兆玉; 王庆国

    2004-01-01

    A practical approach is discussed for sub-sea pipeline monitoring and leak detection based on the real time transient model (RTTM). The characteristic method (CM) of transient simulation is coupled with the Extended Kalman Filter(EKF) to estimate the system state where the only observed data are inlet and outlet flow rate and pressure. Because EKF has a time variant track under the non-stationary stochastic process with additive Gaussian noise, the high sensitivity of RTTM to non-stationary operating condition is reduced. A leak location recursion estimation formula is presented based on the real time observed data. The results of 27 groups of test data indicate that the procedure presented is sensitive to a wide range of detectable leak sizes ( 1.5% ~ 57% of inlet flow rate) and has a low average relative error of leak location(<5%).

  3. New Sensor Cable for the Detection and Location of Leaks in Pipelines for Transportation of Hydrocarbons

    Directory of Open Access Journals (Sweden)

    E.Orduña-Reyes

    2012-08-01

    Full Text Available At present, hydrocarbon leaks, generated mainly by corrosion of pipelines, cause large economic losses for Mexico.These leaks constitute a problem of serious consequences in Mexico and in other countries in the world. This workdescribes the results of the tests conducted on a new sensor cable for the detection and location of leaks in pipelinesfor transportation of hydrocarbons. When a liquid or gas enters in contact with the wall of the sensor cable, it causes ashort circuit in the wires; changing the measurement of the resistance may detect and locate the leak. The new sensorcable that is presented in this article has advantages over cables with similar characteristic made in other countries.The use of this sensor cable in pipelines of PEMEX will avoid economic losses, environmental damage and risks ofpossible explosions to the population. The experimental results demonstrate these advantages.

  4. Leaks in gas pipelines. Leak detection with the aid of GIS and GPS; Leckstellen in Gasrohrnetzen. Aufspueren mit Unterstuetzung durch GIS und GPS

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Detlef; Berteld, Michael [Industrielle Werke Basel (Switzerland)

    2009-12-15

    The GPS technology has made gas leak detection more efficient. By linking it with the documentation of the Geographic Information System (GIS), gas grid monitoring, long-term planning and also maintenance can be optimized considerably. After successful testing, Industrielle Werke Basel (IWB) introduced the system for their whole gas grid. Apart from cost savings, there was also a significant quality improvement in gas leak detection. (orig.)

  5. The genetic-algorithm-enhanced blind system identification for water distribution pipeline leak detection

    Science.gov (United States)

    Yang, Jin; Wen, Yumei; Li, Ping

    2007-07-01

    The conventional leak location is based on the correlation of leak acoustic signals acquired spatially separately. By correlation, the time lag is estimated for localizing the leakage. In these methods, the detection distance is a prerequisite that has to be known beforehand. However, in practice, this prerequisite is not always satisfied. In this case, the correlation-based methods are not feasible. Actually, the acquired signals contain the characteristics related to the acoustic propagation channels; thus the blind system identification strategy is applied to estimate the transmission performances of acoustic channels. Then the times due to the propagation of the leak source signal travelling from the leak point to sensors are determined. In this way, for leak location, the detection distance is no longer a prerequisite. In blind system identification, due to the long impulse responses of the leak acoustic channels, the channels are inevitably ill conditioned and sensitive to the initial values. To overcome the ill conditions, the overlap-save and cross-correlation fitting techniques are utilized to identify the long impulse sequences under a built constraint. In order to avoid converging to the local minima, the genetic algorithm is used to minimize the cost functions. The practical detection results show the validity of the proposed scheme.

  6. Active acoustic leak detection for LMFBR steam generators. Pt. 6. Applicability to practical steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Kazuo; Kumagai, Hiromichi; Kinoshita, Izumi [Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan). Komae Research Lab.

    1998-03-01

    It is necessary to develop a reliable water leak detection system for steam generators of liquid metal reactors in order to prevent the expansion of damage and to maintain the structural integrity of the steam generators. The concept of the active acoustic method is to detect the change of the ultrasonic field due to the hydrogen gas bubbles generated by a sodium-water reaction. This method has the potential for improved detection performance compared with conventional passive methods, from the viewpoint of sensitivity, response time and tolerance against the background noise. A feasibility study of the active acoustic leak detection system is being carried out. This report predicts the performance of the active acoustic method in the practical steam generators from the results of the large scale in-water experiments. The results shows that the active acoustic system can detect a 10 g/s leak within a few seconds in large-scale steam generators. (author)

  7. 75 FR 76742 - Detecting Oil Leaks From Vessels Into the Water

    Science.gov (United States)

    2010-12-09

    ... SECURITY Coast Guard Detecting Oil Leaks From Vessels Into the Water AGENCY: Coast Guard, DHS. ACTION... seeks information about the current state of technology to detect loss of oil into the water. DATES... about the current state of technology to detect loss of oil into the water. All information...

  8. Leak detection in spacecraft using structure-borne noise with distributed sensors

    Science.gov (United States)

    Holland, Stephen D.; Roberts, Ron; Chimenti, D. E.; Strei, Michael

    2005-04-01

    We have developed and tested in the laboratory a method for in-orbit detection and location of air leaks in manned spacecraft that uses only a small number of sensors distributed arbitrarily on the inner surface of the spacecraft skin. Then, structure-borne ultrasound in the range of 300-600 kHz is monitored from each of the sensors. When cross correlations between measured sensor waveforms indicate the presence of a leak, these correlations are compared with a large dynamically generated database of simulated correlations to locate the the leak on the pressure vessel. A series of experimental tests were performed and at worst the method identified some false locations, but the true location of the leak always appeared.

  9. Real-Time Model-Based Leak-Through Detection within Cryogenic Flow Systems

    Science.gov (United States)

    Walker, M.; Figueroa, F.

    2015-01-01

    The timely detection of leaks within cryogenic fuel replenishment systems is of significant importance to operators on account of the safety and economic impacts associated with material loss and operational inefficiencies. Associated loss in control of pressure also effects the stability and ability to control the phase of cryogenic fluids during replenishment operations. Current research dedicated to providing Prognostics and Health Management (PHM) coverage of such cryogenic replenishment systems has focused on the detection of leaks to atmosphere involving relatively simple model-based diagnostic approaches that, while effective, are unable to isolate the fault to specific piping system components. The authors have extended this research to focus on the detection of leaks through closed valves that are intended to isolate sections of the piping system from the flow and pressurization of cryogenic fluids. The described approach employs model-based detection of leak-through conditions based on correlations of pressure changes across isolation valves and attempts to isolate the faults to specific valves. Implementation of this capability is enabled by knowledge and information embedded in the domain model of the system. The approach has been used effectively to detect such leak-through faults during cryogenic operational testing at the Cryogenic Testbed at NASA's Kennedy Space Center.

  10. Studies on the detection of leaks from Tapacura dam

    Energy Technology Data Exchange (ETDEWEB)

    Menezes, Marco O.A.; Andrade Lima, Ricardo de; Antonino, Antonio C.D.; Villar, Heldio P.; Oliveira Lira, Carlos A.B. de [Pernambuco Univ., Recife, PE (Brazil). Dept. de Energia Nuclear; Badeira, Jefferson V. [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil); Viana, Afonso A. [Companhia Pernambucana de Saneamento e Agua, Recife, PE (Brazil); Plata-Bedmar, Antonio [Centro de Estudios y Experimentaciones de Obras Publicas (Spain); Garcia-Agudo, Edmundo [International Atomic Energy Agency, Vienna (Austria)

    1997-12-01

    One of the many applications of stable isotope analyses is in hydrological studies. as the isotope concentration of elements in water vary as a result of fractionation due to physicochemical processes, each water has its own fingerprints, so that identification of its origin is made possible. This technique has been used in the investigation of the possible leaks through the geologic formation underneath the Tapacura Dam, near Recife, Brazil. Samples were collected from the reservoir and from several collection points downstream. These samples have been analysed for their deuterium, {sup 18} O and {sup 13} C concentrations. The comparison between results from these analyses indicated that water from the reservoir and from the other collection points had distinct origins. These finding were corroborated from standard chemical analyses and tracer studies, thus pointing to the absence of any significant underflow at the Tapacura Dam. (author). 4 refs., 1 fig., 4 tabs.

  11. Whole new ball game : pipeline leak detection system undergoes first field trial

    Energy Technology Data Exchange (ETDEWEB)

    Marsters, S.

    2007-07-15

    This article described an innovative and portable technology that detects leaks in oil and gas pipelines. Pure Technologies Ltd. completed the first field trial of its SoundPrint SmartBall, a free-swimming foam ball with an embedded sensor in an aluminum core that detects leaks as the ball moves through the pipe. The technology is based on the premise that sound is released when a pressurized fluid is escaping. The field trial was performed over 18 kilometres of a 10-inch crude oil pipeline in Texas. The SmartBall was first sent through a pipeline without any artificial leaks. It was then sent through a pipeline with an artificial leak constructed at one of the block valves. The SmartBall was able to detect the artificial leak from hundreds of metres away. The device was deployed and retrieved without incident by pipeline operations personnel using existing pigging infrastructure. It was determined that the device can detect leaks of less than 3.78 litres per minute at an operating pressure of 8.6 bars. The size of the SmartBall is generally between 50 to 80 per cent of the diameter of the pipeline and depends on other factors such as location of in-line vales, the size of the appurtenances through which the ball is inserted and retrieved and the presence of other lateral lines. The device records acoustic information as it travels in the pipe. Alternatively, transducers that emit an acoustic pulse can be installed on pipe appurtenances. The leaks can be located by analyzing the relative arrival time of pulses. The device can operate for up to 40 hours, enough to travel 100 kilometres in a single deployment. Pure Technologies is now working on getting this new technology accepted by the industry. 2 figs.

  12. Flight Testing of an Advanced Airborne Natural Gas Leak Detection System

    Energy Technology Data Exchange (ETDEWEB)

    Dawn Lenz; Raymond T. Lines; Darryl Murdock; Jeffrey Owen; Steven Stearns; Michael Stoogenke

    2005-10-01

    ITT Industries Space Systems Division (Space Systems) has developed an airborne natural gas leak detection system designed to detect, image, quantify, and precisely locate leaks from natural gas transmission pipelines. This system is called the Airborne Natural Gas Emission Lidar (ANGEL) system. The ANGEL system uses a highly sensitive differential absorption Lidar technology to remotely detect pipeline leaks. The ANGEL System is operated from a fixed wing aircraft and includes automatic scanning, pointing system, and pilot guidance systems. During a pipeline inspection, the ANGEL system aircraft flies at an elevation of 1000 feet above the ground at speeds of between 100 and 150 mph. Under this contract with DOE/NETL, Space Systems was funded to integrate the ANGEL sensor into a test aircraft and conduct a series of flight tests over a variety of test targets including simulated natural gas pipeline leaks. Following early tests in upstate New York in the summer of 2004, the ANGEL system was deployed to Casper, Wyoming to participate in a set of DOE-sponsored field tests at the Rocky Mountain Oilfield Testing Center (RMOTC). At RMOTC the Space Systems team completed integration of the system and flew an operational system for the first time. The ANGEL system flew 2 missions/day for the duration for the 5-day test. Over the course of the week the ANGEL System detected leaks ranging from 100 to 5,000 scfh.

  13. Volumetric Forest Change Detection Through Vhr Satellite Imagery

    Science.gov (United States)

    Akca, Devrim; Stylianidis, Efstratios; Smagas, Konstantinos; Hofer, Martin; Poli, Daniela; Gruen, Armin; Sanchez Martin, Victor; Altan, Orhan; Walli, Andreas; Jimeno, Elisa; Garcia, Alejandro

    2016-06-01

    Quick and economical ways of detecting of planimetric and volumetric changes of forest areas are in high demand. A research platform, called FORSAT (A satellite processing platform for high resolution forest assessment), was developed for the extraction of 3D geometric information from VHR (very-high resolution) imagery from satellite optical sensors and automatic change detection. This 3D forest information solution was developed during a Eurostars project. FORSAT includes two main units. The first one is dedicated to the geometric and radiometric processing of satellite optical imagery and 2D/3D information extraction. This includes: image radiometric pre-processing, image and ground point measurement, improvement of geometric sensor orientation, quasiepipolar image generation for stereo measurements, digital surface model (DSM) extraction by using a precise and robust image matching approach specially designed for VHR satellite imagery, generation of orthoimages, and 3D measurements in single images using mono-plotting and in stereo images as well as triplets. FORSAT supports most of the VHR optically imagery commonly used for civil applications: IKONOS, OrbView - 3, SPOT - 5 HRS, SPOT - 5 HRG, QuickBird, GeoEye-1, WorldView-1/2, Pléiades 1A/1B, SPOT 6/7, and sensors of similar type to be expected in the future. The second unit of FORSAT is dedicated to 3D surface comparison for change detection. It allows users to import digital elevation models (DEMs), align them using an advanced 3D surface matching approach and calculate the 3D differences and volume changes between epochs. To this end our 3D surface matching method LS3D is being used. FORSAT is a single source and flexible forest information solution with a very competitive price/quality ratio, allowing expert and non-expert remote sensing users to monitor forests in three and four dimensions from VHR optical imagery for many forest information needs. The capacity and benefits of FORSAT have been tested in

  14. EXTENDED PERFORMANCE HANDHELD AND MOBILE SENSORS FOR REMOTE DETECTION OF NATURAL GAS LEAKS

    Energy Technology Data Exchange (ETDEWEB)

    Michael B. Frish; B. David Green; Richard T. Wainner; Francesca Scire-Scappuzzo; Paul Cataldi; Matthew C. Laderer

    2005-05-01

    This report summarizes work performed by Physical Sciences Inc. (PSI) to advance the state-of-the-art of surveying for leaks of natural gas from transmission and distribution pipelines. The principal project goal was to develop means of deploying on an automotive platform an improved version of the handheld laser-based standoff natural gas leak detector previously developed by PSI and known as the Remote Methane Leak Detector or RMLD. A laser beam which interrogates the air for methane is projected from a spinning turret mounted upon a van. As the van travels forward, the laser beam scans an arc to the front and sides of the van so as to survey across streets and to building walls from a moving vehicle. When excess methane is detected within the arc, an alarm is activated. In this project, we built and tested a prototype Mobile RMLD (MRMLD) intended to provide lateral coverage of 10 m and one lateral scan for every meter of forward motion at forward speeds up to 10 m/s. Using advanced detection algorithms developed as part of this project, the early prototype MRMLD, installed on the back of a truck, readily detected simulated gas leaks of 50 liters per hour. As a supplement to the originally planned project, PSI also participated in a DoE demonstration of several gas leak detection systems at the Rocky Mountain Oilfield Testing Center (RMOTC) during September 2004. Using a handheld RMLD upgraded with the advanced detection algorithms developed in this project, from within a moving vehicle we readily detected leaks created along the 7.4 mile route of a virtual gas transmission pipeline.

  15. Comparative study of instantaneous frequency based methods for leak detection in pipeline networks

    Science.gov (United States)

    Ghazali, M. F.; Beck, S. B. M.; Shucksmith, J. D.; Boxall, J. B.; Staszewski, W. J.

    2012-05-01

    Methods of pressure transient analysis can be seen as a promising, accurate and low-cost tool for leak and feature detection in pipelines. Various systems have been developed by several groups of researchers in recent years. Such techniques have been successfully demonstrated under laboratory conditions but are not yet established for use with real field test data. The current paper presents a comparative study of instantaneous frequency analysis techniques based on pressure transients recorded within a live distribution network. The instantaneous frequency of the signals are analysed using the Hilbert transform (HT), the Normalised Hilbert transform (NHT), Direct Quadrature (DQ), Teager Energy Operator (TEO) and Cepstrum. This work demonstrates the effectiveness of the instantaneous frequency analysis in detecting a leaks and other features within the network. NHT and DQ allowed for the identification of the approximate location of leaks. The performance TEO is moderate, with Cepstrum being the worst performing method.

  16. Water Pipeline Monitoring and Leak Detection using Flow Liquid Meter Sensor

    Science.gov (United States)

    Rahmat, R. F.; Satria, I. S.; Siregar, B.; Budiarto, R.

    2017-04-01

    Water distribution is generally installed through underground pipes. Monitoring the underground water pipelines is more difficult than monitoring the water pipelines located on the ground in open space. This situation will cause a permanent loss if there is a disturbance in the pipeline such as leakage. Leaks in pipes can be caused by several factors, such as the pipe’s age, improper installation, and natural disasters. Therefore, a solution is required to detect and to determine the location of the damage when there is a leak. The detection of the leak location will use fluid mechanics and kinematics physics based on harness water flow rate data obtained using flow liquid meter sensor and Arduino UNO as a microcontroller. The results show that the proposed method is able to work stably to determine the location of the leak which has a maximum distance of 2 metres, and it’s able to determine the leak location as close as possible with flow rate about 10 litters per minute.

  17. [Usefulness of upper gastrointestinal series to detect leaks in the early postoperative period of bariatric surgery].

    Science.gov (United States)

    Medina, Francisco J; Miranda-Merchak, Andrés; Martínez, Alonso; Sánchez, Felipe; Bravo, Sebastián; Contreras, Juan Eduardo; Alliende, Isabel; Canals, Andrea

    2016-04-01

    Postoperative leaks are the most undesirable complication of bariatric surgery and upper gastrointestinal (GI) series are routinely ordered to rule them out. Despite the published literature recommending against its routine use, it is still being customarily used in Chile. To examine the usefulness of routine upper GI series using water-soluble iodinated contrast media for the detection of early postoperative leaks in patients undergoing bariatric surgery. A cohort of 328 patients subjected to bariatric surgery was followed from October 2012 to October 2013. Most of them underwent sleeve gastrectomy. Upper GI series on the first postoperative day were ordered to 308 (94%) patients. Postoperative leaks were observed in two patients, with an incidence of 0.6%. The sensitivity for upper GI series detection of leak was 0% and the negative predictive value was 99%. Routine upper GI series after bariatric surgery is not useful for the diagnosis of postoperative leak, given the low incidence of this complication and the low sensitivity of the technique.

  18. Technical bases for leak detection surveillance of waste storage tanks. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, M.G.; Badden, J.J.

    1995-02-13

    This document provides the technical bases for specification limits, monitoring frequencies and baselines used for leak detection and intrusion (for single shell tanks only) in all single and double shell radioactive waste storage tanks, waste transfer lines, and most catch tanks and receiver tanks in the waste tank farms and associated areas at Hanford.

  19. Functionalized multi-walled carbon nanotube based sensors for distributed methane leak detection

    Science.gov (United States)

    This paper presents a highly sensitive, energy efficient and low-cost distributed methane (CH4) sensor system (DMSS) for continuous monitoring, detection and localization of CH4 leaks in natural gas infrastructure such as transmission and distribution pipelines, wells, and produc...

  20. Feasibility of leak-detection instrumentation for duplex-tube steam generator. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Berkey, E.; Witkowski, R.E.

    1974-01-01

    A literature search has been carried out to determine if current state-of-the-art for sodium vapor and water vapor detectors are feasible as leak detection instrumentation for the Westinghouse duplex-tube steam generator. A commercially available probe-type water vapor detector has been identified and a thermal ionization type sodium vapor detector, currently being developed by Westinghouse, has been selected as the reference sodium-vapor leak detector. Recommendations are made concerning the experimental studies required to adapt the selected instrumentation to steam-generator plant applications. Proposed future instrumentation development programs are also identified.

  1. Hierarchical leak detection and localization method in natural gas pipeline monitoring sensor networks.

    Science.gov (United States)

    Wan, Jiangwen; Yu, Yang; Wu, Yinfeng; Feng, Renjian; Yu, Ning

    2012-01-01

    In light of the problems of low recognition efficiency, high false rates and poor localization accuracy in traditional pipeline security detection technology, this paper proposes a type of hierarchical leak detection and localization method for use in natural gas pipeline monitoring sensor networks. In the signal preprocessing phase, original monitoring signals are dealt with by wavelet transform technology to extract the single mode signals as well as characteristic parameters. In the initial recognition phase, a multi-classifier model based on SVM is constructed and characteristic parameters are sent as input vectors to the multi-classifier for initial recognition. In the final decision phase, an improved evidence combination rule is designed to integrate initial recognition results for final decisions. Furthermore, a weighted average localization algorithm based on time difference of arrival is introduced for determining the leak point's position. Experimental results illustrate that this hierarchical pipeline leak detection and localization method could effectively improve the accuracy of the leak point localization and reduce the undetected rate as well as false alarm rate.

  2. Research and development of a high-temperature helium-leak detection system (joint research). Part 1 survey on leakage events and current leak detection technology

    Energy Technology Data Exchange (ETDEWEB)

    Sakaba, Nariaki; Nakazawa, Toshio; Kawasaki, Kozo [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Urakami, Masao; Saisyu, Sadanori [Japan Atomic Power Co., Tokyo (Japan)

    2003-03-01

    In High Temperature Gas-cooled Reactors (HTGR), the detection of leakage of helium at an early stage is very important for the safety and stability of operations. Since helium is a colourless gas, it is generally difficult to identify the location and the amount of leakage when very little leakage has occurred. The purpose of this R and D is to develop a helium leak detection system for the high temperature environment appropriate to the HTGR. As the first step in the development, this paper describes the result of surveying leakage events at nuclear facilities inside and outside Japan and current gas leakage detection technology to adapt optical-fibre detection technology to HTGRs. (author)

  3. Leak detection in gas pipeline by acoustic and signal processing - A review

    Science.gov (United States)

    Adnan, N. F.; Ghazali, M. F.; Amin, M. M.; Hamat, A. M. A.

    2015-12-01

    The pipeline system is the most important part in media transport in order to deliver fluid to another station. The weak maintenance and poor safety will contribute to financial losses in term of fluid waste and environmental impacts. There are many classifications of techniques to make it easier to show their specific method and application. This paper's discussion about gas leak detection in pipeline system using acoustic method will be presented in this paper. The wave propagation in the pipeline is a key parameter in acoustic method when the leak occurs and the pressure balance of the pipe will generated by the friction between wall in the pipe. The signal processing is used to decompose the raw signal and show in time- frequency. Findings based on the acoustic method can be used for comparative study in the future. Acoustic signal and HHT is the best method to detect leak in gas pipelines. More experiments and simulation need to be carried out to get the fast result of leaking and estimation of their location.

  4. Development, application & assessment of improved condenser leak detection program at Brayton Point Station

    Energy Technology Data Exchange (ETDEWEB)

    Medina, C.A.; Bennett, B.A.; Thornton, M.W.

    1996-08-01

    The adverse impacts of air inleakage on condenser performance are well known and include elevated turbine back pressure, increased parasitic loads (to remove elevated levels of noncondensables from the condenser), and high dissolved oxygen levels in the feedwater cycle. Prolonged neglect of leakage leads to increased maintenance to feedwater and air removal systems as well as reduced cycle efficiency and the potential of a unit trip on high turbine back pressure. Leak detection performed on a scheduled basis, just prior to a scheduled outage, is an effective preventive maintenance activity for older stations and important for newer stations concerned with heat rate degradation and equipment performance. New England Power began a comprehensive air inleakage reduction program at its Brayton Point Generating Station (BPS) in 1990. The authors describe the development and application on Units 1 through 4, including its unique identification and documentation tools and its computerized leak source tracking and trending software program. Actual results gained from the programs use at BPS will be presented. To put the merits of the program in perspective, historically, many real and potentially large leak paths were not being tested, because helium leak detection crews normally inspected familiar and easy-to-reach areas around the condenser. Tracking and trending was practically non-existent, providing little documentation for root cause analysis when a large leak is suspect. Since the improved program was implemented at BPS, air in-leakage detection has increased by 300 percent, in-leakage rates have reduced 40% and turbine backpressure levels have improved. Station personnel now have a tool to diagnose condenser air in-leakage with test repeatability, whether it be a sudden incident of high in-leakage demanding immediate testing and repair or gradual increases which can be identified during pre-outage testing for repair during their scheduled outage. 3 figs., 2 tabs.

  5. 40 CFR Table 6 to Subpart IIIii of... - Examples of Techniques for Equipment Problem Identification, Leak Detection and Mercury Vapor

    Science.gov (United States)

    2010-07-01

    ...; cracks or spalling in cell room floors, pillars, or beams; caustic leaks; liquid mercury accumulations or... Problem Identification, Leak Detection and Mercury Vapor 6 Table 6 to Subpart IIIII of Part 63 Protection... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Pt. 63, Subpt....

  6. SmartPipes: Smart Wireless Sensor Networks for Leak Detection in Water Pipelines

    Directory of Open Access Journals (Sweden)

    Ali M. Sadeghioon

    2014-02-01

    Full Text Available Asset monitoring, specifically infrastructure monitoring such as water distribution pipelines, is becoming increasingly critical for utility owners who face new challenges due to an aging network. In the UK alone, during the period of 2009–2010, approximately 3281 mega litres (106 of water were wasted due to failure or leaks in water pipelines. Various techniques can be used for the monitoring of water distribution networks. This paper presents the design, development and testing of a smart wireless sensor network for leak detection in water pipelines, based on the measurement of relative indirect pressure changes in plastic pipes. Power consumption of the sensor nodes is minimised to 2.2 mW based on one measurement every 6 h in order to prolong the lifetime of the network and increase the sensor nodes’ compatibility with current levels of power available by energy harvesting methods and long life batteries. A novel pressure sensing method is investigated for its performance and capabilities by both laboratory and field trials. The sensors were capable of measuring pressure changes due to leaks. These pressure profiles can also be used to locate the leaks.

  7. A Fiber-Optic Sensor for Leak Detection in a Space Environment

    Science.gov (United States)

    Sinko, John E.; Korman, Valentin; Hendrickson, Adam; Polzin, Kurt A.

    2009-01-01

    A miniature fiber-optic, laser-based, interferometric leak detector is presented for application as a means to detect on-orbit gas leaks. The sensor employs a fiber-coupled modified Michelson interferometer to detect gas leaks by measuring an increase in gas density in the sensing region. Monitoring changes in the fringe pattern output by the interferometer allows for direct measurement of the gas density in the sensing region and, under the assumption of an equation of state, this can be used to obtain a pressure measurement. Measurements obtained over a pressure range from 20 mtorr to 760 torr using a prototypical interferometer on working gases of air, nitrogen, argon, and helium generally exhibit agreement with a theoretical prediction of the pressure increase required before an interference fringe completely moves over the detector. Additional measurements performed on various gases demonstrate the range of detectable species, measuring sub-torr pressure changes in the process. A high-fidelity measurement places the ultimate pressure resolution for this particular sensor configuration in the 10 mtorr range. Time-resolved data prove the capability of this sensor to detect fast gas flow phenomena associated with transients and pressure waves.

  8. Advanced conceptual design report: T Plant secondary containment and leak detection upgrades. Project W-259

    Energy Technology Data Exchange (ETDEWEB)

    Hookfin, J.D.

    1995-05-12

    The T Plant facilities in the 200-West Area of the Hanford site were constructed in the early 1940s to produce nuclear materials in support of national defense activities. T Plant includes the 271-T facility, the 221-T facility, and several support facilities (eg, 2706-T), utilities, and tanks/piping systems. T Plant has been recommended as the primary interim decontamination facility for the Hanford site. Project W-259 will provide capital upgrades to the T Plant facilities to comply with Federal and State of Washington environmental regulations for secondary containment and leak detection. This document provides an advanced conceptual design concept that complies with functional requirements for the T Plant Secondary Containment and Leak Detection upgrades.

  9. COST AND PERFORMANCE REPORT: INNOVATIVE ACOUSTIC SENSOR TECHNOLOGIES FOR LEAK DETECTION IN CHALLENGING PIPE TYPES

    Science.gov (United States)

    2016-12-30

    Technologies for Leak Detection in Challenging Pipe Types (Cost and Performance Report) Gary Anguiano Edwin Chiang Martha Araujo Stuart Strum Dr. Victor...N3943013C1256 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Gary Anguiano; Edwin Chiang; Martha Araujo; and Stuart Strum (NAVFAC EXWC...Principal Investigator Scott Waisner U.S. Army Engineer R&D Center 3909 Halls Ferry Rd. Vicksburg, MS 39180 (601) 634-2286 (601) 634

  10. Steel Casing Resistivity Technology (SCRT): Innovative Applications of Electrical Methods for Buried Tank Leak Detection

    Science.gov (United States)

    Fink, J. B.; Levitt, M. T.; Gee, G. W.

    2002-12-01

    The need for non-invasive leak detection methods is extremely important for monitoring cleanup efforts of nuclear waste contained in underground storage tanks at the Hanford Nuclear Facility in Washington. Drilling is both very expensive and undesirable in the tank farms. Various geophysical imaging methods were evaluated over the past two years at two "cold" sites but within geologic conditions similar to the tank farms. The "cold" sites consisted of 1. a dense array of 32 steel casings, and 2. a "mock tank" in which various controlled leaks (injections) of a saturated aqueous solution of Na2S2O35H20 were metered. Nearly all methods required invasive drilling for subsurface placement of sensors. An innovative direct-current electrical method using existing infrastructure as grounding electrodes, such as steel casings and steel tanks, has shown very promising results and is undergoing further testing. The most useful results have been obtained by using multiple grounding points for spatial determinations and continuous time-series monitoring for temporal variations. Although the large size of tanks and lengths of casings make discrete volume estimations difficult, data acquired for test leaks to date have shown a surprising correlation between leak rates and the rate-of-change of specific electrical measurements. First order volume approximations can be made based on existing knowledge of the geologic environment and hydraulic parameters. Spatial data provide general leak location and gross flow characteristics, whereas temporal data indicate test leak commencement, cessation, and approximate leak rates. On-going testing is providing quantitative calibration information that is expected to transfer to the tank farm environments. Procedures are being developed that will simplify the installation and operation of the system in the tank-farm environments. Implementation of the technology necessitated remote operation and monitoring of the electrical system

  11. Soil Surface Leak Detection From Carbon Storage Sites Using ∆(CO2:O2) Measurements

    Science.gov (United States)

    Alam, M. M.; Norman, A. L.; Layzell, D. B.

    2015-12-01

    The early detection and remediation of CO2 leaks from Carbon Capture and Storage (CCS) sites is essential for the safety and public support of the technology. A model that integrates gas diffusion, mass flow and biological processes in soils was developed and used to predict the ∆CO2 and ∆O2 concentration differential between the soil surface and the bulk atmosphere under a wide range of environmental conditions that include temperature, soil gas and water content, soil respiratory quotient and rate of O2 uptake, soil porosity and CO2 leakage rate. The results predicted that measurement of ∆(CO2:O2) measurements at the soil surface relative to air should be able to detect a CCS leak as low as 2 µmol/m2/sec. To test this hypothesis, a gas analysis system was designed and constructed. It should allow a series of experiments under controlled conditions to test all aspects of the model. It is hoped that the results from this work will ultimately lead to the development of a new instrument and protocol for the early detection of CO2 leaks from a geological storage sites.

  12. Hyperspectral detection of a subsurface CO2 leak in the presence of water stressed vegetation.

    Science.gov (United States)

    Bellante, Gabriel J; Powell, Scott L; Lawrence, Rick L; Repasky, Kevin S; Dougher, Tracy

    2014-01-01

    Remote sensing of vegetation stress has been posed as a possible large area monitoring tool for surface CO2 leakage from geologic carbon sequestration (GCS) sites since vegetation is adversely affected by elevated CO2 levels in soil. However, the extent to which remote sensing could be used for CO2 leak detection depends on the spectral separability of the plant stress signal caused by various factors, including elevated soil CO2 and water stress. This distinction is crucial to determining the seasonality and appropriateness of remote GCS site monitoring. A greenhouse experiment tested the degree to which plants stressed by elevated soil CO2 could be distinguished from plants that were water stressed. A randomized block design assigned Alfalfa plants (Medicago sativa) to one of four possible treatment groups: 1) a CO2 injection group; 2) a water stress group; 3) an interaction group that was subjected to both water stress and CO2 injection; or 4) a group that received adequate water and no CO2 injection. Single date classification trees were developed to identify individual spectral bands that were significant in distinguishing between CO2 and water stress agents, in addition to a random forest classifier that was used to further understand and validate predictive accuracies. Overall peak classification accuracy was 90% (Kappa of 0.87) for the classification tree analysis and 83% (Kappa of 0.77) for the random forest classifier, demonstrating that vegetation stressed from an underground CO2 leak could be accurately discerned from healthy vegetation and areas of co-occurring water stressed vegetation at certain times. Plants appear to hit a stress threshold, however, that would render detection of a CO2 leak unlikely during severe drought conditions. Our findings suggest that early detection of a CO2 leak with an aerial or ground-based hyperspectral imaging system is possible and could be an important GCS monitoring tool.

  13. Hyperspectral detection of a subsurface CO2 leak in the presence of water stressed vegetation.

    Directory of Open Access Journals (Sweden)

    Gabriel J Bellante

    Full Text Available Remote sensing of vegetation stress has been posed as a possible large area monitoring tool for surface CO2 leakage from geologic carbon sequestration (GCS sites since vegetation is adversely affected by elevated CO2 levels in soil. However, the extent to which remote sensing could be used for CO2 leak detection depends on the spectral separability of the plant stress signal caused by various factors, including elevated soil CO2 and water stress. This distinction is crucial to determining the seasonality and appropriateness of remote GCS site monitoring. A greenhouse experiment tested the degree to which plants stressed by elevated soil CO2 could be distinguished from plants that were water stressed. A randomized block design assigned Alfalfa plants (Medicago sativa to one of four possible treatment groups: 1 a CO2 injection group; 2 a water stress group; 3 an interaction group that was subjected to both water stress and CO2 injection; or 4 a group that received adequate water and no CO2 injection. Single date classification trees were developed to identify individual spectral bands that were significant in distinguishing between CO2 and water stress agents, in addition to a random forest classifier that was used to further understand and validate predictive accuracies. Overall peak classification accuracy was 90% (Kappa of 0.87 for the classification tree analysis and 83% (Kappa of 0.77 for the random forest classifier, demonstrating that vegetation stressed from an underground CO2 leak could be accurately discerned from healthy vegetation and areas of co-occurring water stressed vegetation at certain times. Plants appear to hit a stress threshold, however, that would render detection of a CO2 leak unlikely during severe drought conditions. Our findings suggest that early detection of a CO2 leak with an aerial or ground-based hyperspectral imaging system is possible and could be an important GCS monitoring tool.

  14. Evaluation of an Interferometric Sensor for In-Space Detection of Gas Leaks

    Science.gov (United States)

    Polzin, Kurt A.; Korman, Valentin; Sinko, John; Hendrickson, Adam

    2009-01-01

    Space mission planning often involves long-term storage of volatile liquids or high-pressure gases. These may include cryogenic fuels and oxidizers, high-pressure gases, and life-support-critical consumables. The risk associated with the storage of fluids and gases in space systems has long been an issue and the ability to retain these fluids is often tied to mission success. A leak in the storage or distribution system can cause many different problems, including a simple, but mission endangering, loss of inventory or, in severe cases, unbalanced thrust loads on a flight vehicle. Cryogenic propellants are especially difficult to store, especially over a long duration. The propellant can boil off and be lost through the insulating walls of the tank or simple thermal cycling of the fittings, valves, and propellant feed lines may unseat seals allowing the fluid to escape. Current NASA missions call for long-duration in-space storage of propellants, oxidizers, and life support supplies. Leaks of a scale detectable through a pressure drop in the storage tank are often catastrophic and have long been the focus of ground-based mitigation efforts where redundant systems are often employed. However, there is presently no technology available for detecting and monitoring low-level, but still mission-endangering, gas leaks in space. Standard in-space gas detection methods either have a very limited pressure range over which they operate effectively or are limited to certain gases. Mass spectrometer systems are able to perform the detection tasks, but their size, mass and use of high voltage, which could potentially lead to an arc that ignites a combustible propellent, severely limit their usefulness in a space system. In this paper, we present results from testing of the light-based interferometric gas monitoring and leak detection sensor shown in Fig. 1. The output of the sensor is an interference fringe pattern that is a function of the gas density, and commensurate index

  15. Detecting leaks in gas-filled pressure vessels using acoustic resonances

    Science.gov (United States)

    Gillis, K. A.; Moldover, M. R.; Mehl, J. B.

    2016-05-01

    We demonstrate that a leak from a large, unthermostatted pressure vessel into ambient air can be detected an order of magnitude more effectively by measuring the time dependence of the ratio p/f2 than by measuring the ratio p/T. Here f is the resonance frequency of an acoustic mode of the gas inside the pressure vessel, p is the pressure of the gas, and T is the kelvin temperature measured at one point in the gas. In general, the resonance frequencies are determined by a mode-dependent, weighted average of the square of the speed-of-sound throughout the volume of the gas. However, the weighting usually has a weak dependence on likely temperature gradients in the gas inside a large pressure vessel. Using the ratio p/f2, we measured a gas leak (dM/dt)/M ≈ - 1.3 × 10-5 h-1 = - 0.11 yr-1 from a 300-liter pressure vessel filled with argon at 450 kPa that was exposed to sunshine-driven temperature and pressure fluctuations as large as (dT/dt)/T ≈ (dp/dt)/p ≈ 5 × 10-2 h-1 using a 24-hour data record. This leak could not be detected in a 72-hour record of p/T. (Here M is the mass of the gas in the vessel and t is the time.)

  16. Low-cost lightweight airborne laser-based sensors for pipeline leak detection and reporting

    Science.gov (United States)

    Frish, Michael B.; Wainner, Richard T.; Laderer, Matthew C.; Allen, Mark G.; Rutherford, James; Wehnert, Paul; Dey, Sean; Gilchrist, John; Corbi, Ron; Picciaia, Daniele; Andreussi, Paolo; Furry, David

    2013-05-01

    Laser sensing enables aerial detection of natural gas pipeline leaks without need to fly through a hazardous gas plume. This paper describes adaptations of commercial laser-based methane sensing technology that provide relatively low-cost lightweight and battery-powered aerial leak sensors. The underlying technology is near-infrared Standoff Tunable Diode Laser Absorption Spectroscopy (sTDLAS). In one configuration, currently in commercial operation for pipeline surveillance, sTDLAS is combined with automated data reduction, alerting, navigation, and video imagery, integrated into a single-engine single-pilot light fixed-wing aircraft or helicopter platform. In a novel configuration for mapping landfill methane emissions, a miniaturized ultra-lightweight sTDLAS sensor flies aboard a small quad-rotor unmanned aerial vehicle (UAV).

  17. Operational safety and post-maintenance gas leak detection in GE frame 9001FA gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Farthing, D.A.; Marley, L.; Lees, J.A. [PowerGen plc, Connah' s Quay Power Station, Deeside (United Kingdom)

    1999-12-01

    The increased use of natural-gas-fuelled combined cycle gas turbine and combined heat and power plants in recent years has been accompanied by the practice of constructing acoustic enclosures around the gas turbines for environmental reasons. This can increase the risk of an explosion if, for any reason, there is a build-up of flammable gas within the enclosure, since there can be a range of possible ignition sources. The UK Health and Safety Executive consider gas leaks within such enclosures to be foreseeable, especially following maintenance. The paper presents a review of operational safety and a leak detection method for the inspection and design of flanged joints within the acoustic enclosures around GE 9001FA gas turbines, providing a practical step towards minimising the risk of explosion due to fuel leakage. (Author)

  18. Long-wave infrared imaging of vegetation for detecting leaking CO2 gas

    Science.gov (United States)

    Johnson, Jennifer E.; Shaw, Joseph A.; Lawrence, Rick; Nugent, Paul W.; Dobeck, Laura M.; Spangler, Lee H.

    2012-01-01

    The commercial development of uncooled-microbolometer, long-wave infrared (LWIR) imagers, combined with advanced radiometric calibration methods developed at Montana State University, has led to new uses of thermal imagery in remote sensing applications. One specific novel use of these calibrated imagers is imaging of vegetation for CO2 gas leak detection. During a four-week period in the summer of 2011, a CO2 leak was simulated in a test field run by the Zero Emissions Research and Technology Center in Bozeman, Montana. An LWIR imager was deployed on a scaffold before and during the CO2 release, viewing a vegetation test area that included regions of high and low CO2 flux. Increased root-level CO2 concentration caused plant stress that led to reduced thermal regulation of the vegetation, which was consistent with increased diurnal variation of IR emission observed in this study. In a linear regression, the IR data were found to have a strong relationship to the CO2 emission and to be consistent with the location of leaking CO2 gas. Reducing the continuous data set to one image per day weakened the regression fit, but maintained sufficient significance to indicate that this method could be implemented with once-daily airborne images.

  19. Enhanced detection of groundwater contamination from a leaking waste disposal site by microbial community profiles

    Science.gov (United States)

    Mouser, Paula J.; Rizzo, Donna M.; Druschel, Gregory K.; Morales, Sergio E.; Hayden, Nancy; O'Grady, Patrick; Stevens, Lori

    2010-12-01

    Groundwater biogeochemistry is adversely impacted when municipal solid waste leachate, rich in nutrients and anthropogenic compounds, percolates into the subsurface from leaking landfills. Detecting leachate contamination using statistical techniques is challenging because well strategies or analytical techniques may be insufficient for detecting low levels of groundwater contamination. We sampled profiles of the microbial community from monitoring wells surrounding a leaking landfill using terminal restriction fragment length polymorphism (T-RFLP) targeting the 16S rRNA gene. Results show in situ monitoring of bacteria, archaea, and the family Geobacteraceae improves characterization of groundwater quality. Bacterial T-RFLP profiles showed shifts correlated to known gradients of leachate and effectively detected changes along plume fringes that were not detected using hydrochemical data. Experimental sediment microcosms exposed to leachate-contaminated groundwater revealed a shift from a β-Proteobacteria and Actinobacteria dominated community to one dominated by Firmicutes and δ-Proteobacteria. This shift is consistent with the transition from oxic conditions to an anoxic, iron-reducing environment as a result of landfill leachate-derived contaminants and associated redox conditions. We suggest microbial communities are more sensitive than hydrochemistry data for characterizing low levels of groundwater contamination and thus provide a novel source of information for optimizing detection and long-term monitoring strategies at landfill sites.

  20. Development of active acoustic method for water leak detection of LMFBR steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, Hiromichi; Yoshida, Kazuo; Kinoshita, Izumi [Central Research Inst. of Electric Power Industry, Tokyo (Japan)

    2001-06-01

    In order to prevent the expansion of tube damage and to maintain structural integrity in the steam generators (SGs) of fast breeder reactors (FBRs), it is necessary to detect precisely and immediately the leakage of water from heat transfer tubes. Therefore, an active acoustic method, which detects the sound attenuation due to bubbles generated in the sodium-water reactions, is being developed. In this study, in order to evaluate the detection sensitivity of the active method, the signal processing methods for emitter and receiver and the detection method for leakage are investigated experimentally. In-water experiments performed by using an SG full-sector model that simulates the actual SGs. As an experimental result, the received sound attenuation for 10s was more than 10dB from air bubble injection when injected bubble of 10 l/s (equivalence water leak rate about 10 g/s.) The attenuation of sound are least affected by bubble injection position of heat transfer tubes bunch department. It is clarified that the background noise hardly influenced water leak detection performance as a result of having examined influence of background noise. (author)

  1. Detecting Methane From Leaking Pipelines and as Greenhouse Gas in the Atmosphere

    Science.gov (United States)

    Riris, Haris; Numata, Kenji; Li, Steven; Wu, Stewart; Ramanathan, Anand; Dawsey, Martha

    2012-01-01

    Laser remote sensing measurements of trace gases from orbit can provide unprecedented information about important planetary science and answer critical questions about planetary atmospheres. Methane (CH4) is the second most important anthropogenically produced greenhouse gas. Though its atmospheric abundance is much less than that of CO2 (1.78 ppm vs. 380 ppm), it has much larger greenhouse heating potential. CH4 also contributes to pollution in the lower atmosphere through chemical reactions, leading to ozone production. Atmospheric CH4 concentrations have been increasing as a result of increased fossil fuel production, rice farming, livestock, and landfills. Natural sources of CH4 include wetlands, wild fires, and termites, and perhaps other unknown sources. Important sinks for CH4 include non-saturated soils and oxidation by hydroxyl radicals in the atmosphere. Remotely measuring CH4 and other biogenic molecules (such as ethane and formaldehyde) on Mars also has important implications on the existence of life on Mars. Measuring CH4 at very low (ppb) concentrations from orbit will dramatically improve the sensitivity and spatial resolution in the search for CH4 vents and sub-surface life on other planets. A capability has been developed using lasers and spectroscopic detection techniques for the remote measurements of trace gases in open paths. Detection of CH4, CO2, H2O, and CO in absorption cells and in open paths, both in the mid- IR and near-IR region, has been demonstrated using an Optical Parametric Amplifier laser transmitter developed at GSFC. With this transmitter, it would be possible to develop a remote sensing methane instrument. CH4 detection also has very important commercial applications. Pipeline leak detection from an aircraft or a helicopter can significantly reduce cost, response time, and pinpoint the location. The main advantage is the ability to rapidly detect CH4 leaks remotely. This is extremely important for the petrochemical industry

  2. A case of spontaneous cerebrospinal fluid rhinorrhea: Accurate detection of the leak point by magnetic resonance cisternography

    Directory of Open Access Journals (Sweden)

    Teppei Matsubara

    2014-01-01

    Full Text Available Background: Spontaneous cerebrospinal fluid (CSF rhinorrhea is a rare entity. The accurate preoperative localization of the leak point is essential for planning surgical treatment, but is sometimes difficult. To localize the leak point, magnetic resonance cisternography (MRC is the method of choice, but its effectiveness remains unclear. Case Description: A 34-year-old mildly obese female experienced spontaneous CSF rhinorrhea after an attack of bronchial asthma. High-resolution computed tomography (CT failed to reveal the leak point, while MRC demonstrated an arachnoid herniation at the olfactory cleft. The patient underwent endoscopic endonasal repair of the CSF leak with success. There has been no recurrence of CSF rhinorrhea for 14 months after surgery followed by the administration of acetazolamide. Conclusion: We report a rare case of spontaneous CSF rhinorrhea associated with benign intracranial hypertension, in which the leak point was successfully detected by MRC. The CSF leak was completely repaired by minimally invasive endoscopic endonasal surgery. MRC may be a reliable method for detecting CSF leak points.

  3. Intelligent leak detection system for oil pipelines; Sistema inteligente para deteccao de vazamentos em dutos de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Ricardo Dantas Gadelha de [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2003-07-01

    One of the most challenging tasks in an oil field is implementation of a software-based leak detection system on a multi-phase flow pipeline. This paper will discuss implementation of a leak detection system in a particular oil field using state-of-the-art signal processing techniques to apply to the data collected in a oil pipeline. This leak detection system is still in development and uses a more practical approach to the problem than traditional methods and was implemented on a PC under the Windows operating system. Windowing, joint time-frequency analysis and wavelets were considered to develop methods of detecting leaks by watching for the wavefront. The idea behind these techniques is to cut the signal of interest into several parts and then analyze the parts separately. It is impossible to know the exact frequency and the exact time of occurrence of the leak frequency in a signal. In other words, a leak signal can simply not be represented as a point in the time-frequency space. It is very important how one cuts the signal to implement the analysis. The wavelet transform or wavelet analysis is probably the most recent solution to overcome the shortcomings of the Fourier transform. So, this paper shows some tests and how these techniques are being implementing during the development of the system. (author)

  4. Application of Morphological Segmentation to Leaking Defect Detection in Sewer Pipelines

    Directory of Open Access Journals (Sweden)

    Tung-Ching Su

    2014-05-01

    Full Text Available As one of major underground pipelines, sewerage is an important infrastructure in any modern city. The most common problem occurring in sewerage is leaking, whose position and failure level is typically identified through closed circuit television (CCTV inspection in order to facilitate rehabilitation process. This paper proposes a novel method of computer vision, morphological segmentation based on edge detection (MSED, to assist inspectors in detecting pipeline defects in CCTV inspection images. In addition to MSED, other mathematical morphology-based image segmentation methods, including opening top-hat operation (OTHO and closing bottom-hat operation (CBHO, were also applied to the defect detection in vitrified clay sewer pipelines. The CCTV inspection images of the sewer system in the 9th district, Taichung City, Taiwan were selected as the experimental materials. The segmentation results demonstrate that MSED and OTHO are useful for the detection of cracks and open joints, respectively, which are the typical leakage defects found in sewer pipelines.

  5. Leak detection in medium density polyethylene (MDPE) pipe using pressure transient method

    Science.gov (United States)

    Amin, M. M.; Ghazali, M. F.; PiRemli, M. A.; Hamat, A. M. A.; Adnan, N. F.

    2015-12-01

    Water is an essential part of commodity for a daily life usage for an average person, from personal uses such as residential or commercial consumers to industries utilization. This study emphasizes on detection of leaking in medium density polyethylene (MDPE) pipe using pressure transient method. This type of pipe is used to analyze the position of the leakage in the pipeline by using Ensemble Empirical Mode Decomposition Method (EEMD) with signal masking. Water hammer would induce an impulse throughout the pipeline that caused the system turns into a surge of water wave. Thus, solenoid valve is used to create a water hammer through the pipelines. The data from the pressure sensor is collected using DASYLab software. The data analysis of the pressure signal will be decomposed into a series of wave composition using EEMD signal masking method in matrix laboratory (MATLAB) software. The series of decomposition of signals is then carefully selected which reflected intrinsic mode function (IMF). These IMFs will be displayed by using a mathematical algorithm, known as Hilbert transform (HT) spectrum. The IMF signal was analysed to capture the differences. The analyzed data is compared with the actual measurement of the leakage in term of percentage error. The error recorded is below than 1% and it is proved that this method highly reliable and accurate for leak detection.

  6. Detecting proton exchange membrane fuel cell hydrogen leak using electrochemical impedance spectroscopy method

    Science.gov (United States)

    Mousa, Ghassan; Golnaraghi, Farid; DeVaal, Jake; Young, Alan

    2014-01-01

    When a proton exchange membrane (PEM) fuel cell runs short of hydrogen, it suffers from a reverse potential fault that, when driven by neighboring cells, can lead to anode catalyst degradation and holes in the membrane due to local heat generation. As a result, hydrogen leaks through the electrically-shorted membrane-electrode assembly (MEA) without being reacted, and a reduction in fuel cell voltage is noticed. Such voltage reduction can be detected by using electrochemical impedance spectroscopy (EIS). To fully understand the reverse potential fault, the effect of hydrogen crossover leakage in a commercial MEA is measured by EIS at different differential pressures between the anode and cathode. Then the signatures of these leaky cells were compared with the signatures of a no-leaky cells at different oxygen concentrations with the same current densities. The eventual intent of this early stage work is to develop an on-board diagnostics system that can be used to detect and possibly prevent cell reversal failures, and to permit understanding the status of crossover or transfer leaks versus time in operation.

  7. Development of Mathematical Models for Detecting Micron Scale Volumetric Defects in Thin Film Coatings

    Directory of Open Access Journals (Sweden)

    Gaigals G.

    2016-04-01

    Full Text Available The focus of the present research is to investigate possibilities of volumetric defect detection in thin film coatings on glass substrates by means of high definition imaging with no complex optical systems, such as lenses, and to determine development and construction feasibility of a defectoscope employing the investigated methods. Numerical simulations were used to test the proposed methods. Three theoretical models providing various degrees of accuracy and feasibility were studied.

  8. LIBS Sensor for Sub-surface CO2 Leak Detection in Carbon Sequestration

    Directory of Open Access Journals (Sweden)

    Jinesh JAIN

    2017-07-01

    Full Text Available Monitoring carbon sequestration poses numerous challenges to the sensor community. For example, the subsurface environment is notoriously harsh, with large potential mechanical, thermal, and chemical stresses, making long-term stability and survival a challenge to any potential in situ monitoring method. Laser induced breakdown spectroscopy (LIBS has been demonstrated as a promising technology for chemical monitoring of harsh environments and hard to reach places. LIBS has a real- time monitoring capability and can be used for the elemental and isotopic analysis of solid, liquid, and gas samples. The flexibility of the probe design and the use of fiber- optics has made LIBS particularly suited for remote measurements. The paper focuses on developing a LIBS instrument for downhole high-pressure, high-temperature brine experiments, where CO2 leakage could result in changes in the trace mineral composition of an aquifer. The progress in fabricating a compact, robust, and simple LIBS sensor for widespread subsurface leak detection is presented.

  9. Passive acoustic leak detection for sodium cooled fast reactors using hidden Markov models

    Energy Technology Data Exchange (ETDEWEB)

    Riber Marklund, A. [CEA, Cadarache, DEN/DTN/STCP/LIET, Batiment 202, 13108 St Paul-lez-Durance, (France); Kishore, S. [Fast Reactor Technology Group of IGCAR, (India); Prakash, V. [Vibrations Diagnostics Division, Fast Reactor Technology Group of IGCAR, (India); Rajan, K.K. [Fast Reactor Technology Group and Engineering Services Group of IGCAR, (India)

    2015-07-01

    Acoustic leak detection for steam generators of sodium fast reactors have been an active research topic since the early 1970's and several methods have been tested over the years. Inspired by its success in the field of automatic speech recognition, we here apply hidden Markov models (HMM) in combination with Gaussian mixture models (GMM) to the problem. To achieve this, we propose a new feature calculation scheme, based on the temporal evolution of the power spectral density (PSD) of the signal. Using acoustic signals recorded during steam/water injection experiments done at the Indira Gandhi Centre for Atomic Research (IGCAR), the proposed method is tested. We perform parametric studies on the HMM+GMM model size and demonstrate that the proposed method a) performs well without a priori knowledge of injection noise, b) can incorporate several noise models and c) has an output distribution that simplifies false alarm rate control. (authors)

  10. Air Conditioning Compressor Air Leak Detection by Image Processing Techniques for Industrial Applications

    Directory of Open Access Journals (Sweden)

    Pookongchai Kritsada

    2015-01-01

    Full Text Available This paper presents method to detect air leakage of an air conditioning compressor using image processing techniques. Quality of air conditioning compressor should not have air leakage. To test an air conditioning compressor leak, air is pumped into a compressor and then submerged into the water tank. If air bubble occurs at surface of the air conditioning compressor, that leakage compressor must be returned for maintenance. In this work a new method to detect leakage and search leakage point with high accuracy, fast, and precise processes was proposed. In a preprocessing procedure to detect the air bubbles, threshold and median filter techniques have been used. Connected component labeling technique is used to detect the air bubbles while blob analysis is searching technique to analyze group of the air bubbles in sequential images. The experiments are tested with proposed algorithm to determine the leakage point of an air conditioning compressor. The location of the leakage point was presented as coordinated point. The results demonstrated that leakage point during process could be accurately detected. The estimation point had error less than 5% compared to the real leakage point.

  11. Visual detection of gas shows from coal core and cuttings using liquid leak detector

    Energy Technology Data Exchange (ETDEWEB)

    Barker, C.E. [United States Geological Survey, Denver, CO (United States)

    2006-09-15

    Coal core descriptions are difficult to obtain, as they must be obtained immediately after the core is retrieved and before the core is closed in a canister. This paper described a method of marking gas shows on a core surface by coating the core with a water-based liquid leak detector and photographing the subsequent foam developed on the core surface while the core is still in the core tray. Coals from a borehole at the Yukon Flats Basin in Alaska and the Maverick Basin in Texas were used to illustrate the method. Drilling mud and debris were removed from the coal samples before the leak detector solution was applied onto the core surfaces. A white froth or dripping foam developed rapidly at gas shows on the sample surfaces. A hand-held lens and a binocular microscope were used to magnify the foaming action. It was noted that foaming was not continuous across the core surface, but was restricted to localized points along the surface. It was suggested that the localized point foaming may have resulted from the coring process. However, the same tendency toward point gas show across the sample surface was found in some hard, well-indurated samples that still had undisturbed bedding and other sedimentary structures. It was concluded that gas shows marked as separate foam centres may indicate a real condition of local permeability paths. Results suggested that the new gas show detection method could be used in core selection studies to reduce the costs of exploration programs. 6 refs., 4 figs.

  12. FIELD DEMONSTRATION OF INNOVATIVE LEAK DETECTION/LOCATION TECHNOLOGIES COUPLED WITH WALL-THICKNESS SCREENING FOR WATER MAINS

    Science.gov (United States)

    The U.S. Environmental Protection Agency sponsored a large-scale field demonstration of innovative leak detection/location and condition assessment technologies on a 76-year old, 2,500-ft long, cement-lined, 24-in. cast iron water main in Louisville, KY from July through Septembe...

  13. Highly precise atmospheric oxygen measurements as a tool to detect leaks of carbon dioxide from Carbon Capture and Storage sites

    NARCIS (Netherlands)

    van Leeuwen, Charlotte

    2015-01-01

    In Carbon Capture and Storage (CCS), carbon dioxide (CO2) from fossil fuel combustion is stored underground into a geological formation. Although the storage of CO2 is considered as safe, leakage to the atmosphere is an important concern and monitoring is necessary. Detecting and quantifying leaks o

  14. Highly precise atmospheric oxygen measurements as a tool to detect leaks of carbon dioxide from Carbon Capture and Storage sites

    NARCIS (Netherlands)

    van Leeuwen, Charlotte

    2015-01-01

    In Carbon Capture and Storage (CCS), carbon dioxide (CO2) from fossil fuel combustion is stored underground into a geological formation. Although the storage of CO2 is considered as safe, leakage to the atmosphere is an important concern and monitoring is necessary. Detecting and quantifying leaks o

  15. Highly precise atmospheric oxygen measurements as a tool to detect leaks of carbon dioxide from Carbon Capture and Storage sites

    NARCIS (Netherlands)

    van Leeuwen, Charlotte

    2015-01-01

    In Carbon Capture and Storage (CCS), carbon dioxide (CO2) from fossil fuel combustion is stored underground into a geological formation. Although the storage of CO2 is considered as safe, leakage to the atmosphere is an important concern and monitoring is necessary. Detecting and quantifying leaks

  16. Doppler method leak detection for LMFBR steam generators. Pt. 1. Experimental results of bubble detection using small models

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, Hiromichi [Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan). Komae Research Lab

    1999-05-01

    To prevent the expansion of the tube damage and to maintain structural integrity in the steam generators (SGs) of fast breeder reactors (FBRs), it is necessary to detect precisely and immediately the leakage of water from heat transfer tubes. Therefore, an active acoustic method was developed. Previous studies have revealed that in practical steam generators the active acoustic method can detect bubbles of 10 l/s within 10 seconds. To prevent the expansion of damage to neighboring tubes, it is necessary to detect smaller leakages of water from the heat transfer tubes. The Doppler method is designed to detect small leakages and to find the source of the leak before damage spreads to neighboring tubes. To evaluate the relationship between the detection sensitivity of the Doppler method and the bubble volume and bubble size, the structural shapes and bubble flow conditions were investigated experimentally, using a small structural model. The results show that the Doppler method can detect the bubbles under bubble flow conditions, and it is sensitive enough to detect small leakages within a short time. The doppler method thus has strong potential for the detection of water leakage in SGs. (author)

  17. A method to detect landmark pairs accurately between intra-patient volumetric medical images.

    Science.gov (United States)

    Yang, Deshan; Zhang, Miao; Chang, Xiao; Fu, Yabo; Liu, Shi; Li, Harold H; Mutic, Sasa; Duan, Ye

    2017-08-23

    An image processing procedure was developed in this study to detect large quantity of landmark pairs accurately in pairs of volumetric medical images. The detected landmark pairs can be used to evaluate of deformable image registration (DIR) methods quantitatively. Landmark detection and pair matching were implemented in a Gaussian pyramid multi-resolution scheme. A 3D scale-invariant feature transform (SIFT) feature detection method and a 3D Harris-Laplacian corner detection method were employed to detect feature points, i.e., landmarks. A novel feature matching algorithm, Multi-Resolution Inverse-Consistent Guided Matching or MRICGM, was developed to allow accurate feature pairs matching. MRICGM performs feature matching using guidance by the feature pairs detected at the lower resolution stage and the higher confidence feature pairs already detected at the same resolution stage, while enforces inverse consistency. The proposed feature detection and feature pair matching algorithms were optimized to process 3D CT and MRI images. They were successfully applied between the inter-phase abdomen 4DCT images of three patients, between the original and the re-scanned radiation therapy simulation CT images of two head-neck patients, and between inter-fractional treatment MRIs of two patients. The proposed procedure was able to successfully detect and match over 6300 feature pairs on average. The automatically detected landmark pairs were manually verified and the mismatched pairs were rejected. The automatic feature matching accuracy before manual error rejection was 99.4%. Performance of MRICGM was also evaluated using seven digital phantom datasets with known ground truth of tissue deformation. On average, 11855 feature pairs were detected per digital phantom dataset with TRE = 0.77 ± 0.72 mm. A procedure was developed in this study to detect large number of landmark pairs accurately between two volumetric medical images. It allows a semi-automatic way to generate the

  18. Applications of a morphological scene change detection (MSCD) for visual leak and failure identification in process and chemical engineering

    Science.gov (United States)

    Tickle, Andrew J.; Harvey, Paul K.; Smith, Jeremy S.

    2010-10-01

    Morphological Scene Change Detection (MSCD) is a process typically tasked at detecting relevant changes in a guarded environment for security applications. This can be implemented on a Field Programmable Gate Array (FPGA) by a combination of binary differences based around exclusive-OR (XOR) gates, mathematical morphology and a crucial threshold setting. The additional ability to set up the system in virtually any location due to the FPGA makes it ideal for insertion into an autonomous mobile robot for patrol duties. However, security is not the only potential of this robust algorithm. This paper details how such a system can be used for the detection of leaks in piping for use in the process and chemical industries and could be deployed as stated in the above manner. The test substance in this work was water, which was pumped either as a liquid or as low pressure steam through a simple pipe configuration with holes at set points to simulate the leaks. These holes were situated randomly at either the center of a pipe (in order to simulate an impact to it) or at a joint or corner (to simulate a failed weld). Imagery of the resultant leaks, which were visualised as drips or the accumulation of steam, which where analysed using MATLAB to determine their pixel volume in order to calibrate the trigger for the MSCD. The triggering mechanism is adaptive to make it possible in theory for the type of leak to be determined by the number of pixels in the threshold of the image and a numerical output signal to state which of the leak situations is being observed. The system was designed using the DSP Builder package from Altera so that its graphical nature is easily comprehensible to the non-embedded system designer. Furthermore, all the data from the DSP Builder simulation underwent verification against MATLAB comparisons using the image processing toolbox in order to validate the results.

  19. Sensitivity and specificity of intrathecal fluorescein and white light excitation for detecting intraoperative cerebrospinal fluid leak in endoscopic skull base surgery: a prospective study.

    Science.gov (United States)

    Raza, Shaan M; Banu, Matei A; Donaldson, Angela; Patel, Kunal S; Anand, Vijay K; Schwartz, Theodore H

    2016-03-01

    The intraoperative detection of CSF leaks during endonasal endoscopic skull base surgery is critical to preventing postoperative CSF leaks. Intrathecal fluorescein (ITF) has been used at varying doses to aid in the detection of intraoperative CSF leaks. However, the sensitivity and specificity of ITF at certain dosages is unknown. A prospective database of all endoscopic endonasal procedures was reviewed. All patients received 25 mg ITF diluted in 10 ml CSF and were pretreated with dexamethasone and Benadryl. Immediately after surgery, the operating surgeon prospectively noted if there was an intraoperative CSF leak and fluorescein was identified. The sensitivity, specificity, and positive and negative predictive power of ITF for detecting intraoperative CSF leak were calculated. Factors correlating with postoperative CSF leak were determined. Of 419 patients, 35.8% of patients did not show a CSF leak. Fluorescein-tinted CSF (true positive) was noted in 59.7% of patients and 0 false positives were encountered. CSF without fluorescein staining (false negative) was noted in 4.5% of patients. The sensitivity and specificity of ITF were 92.9% and 100%, respectively. The negative and positive predictive values were 88.8% and 100%, respectively. Postoperative CSF leaks only occurred in true positives at a rate of 2.8%. ITF is extremely specific and very sensitive for detecting intraoperative CSF leaks. Although false negatives can occur, these patients do not appear to be at risk for postoperative CSF leak. The use of ITF may help surgeons prevent postoperative CSF leaks by intraoperatively detecting and confirming a watertight repair.

  20. ISS Leak Detection and Astrophysics with Lobster-Eye X-Ray Detector Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Demonstrate angular resolution and sensitivity. Successful lab demonstration of ISS leak checking, using nitrogen, electron beam, and Lobster x-ray optic. 

  1. A survey on the state-of-the-technique on software based pipeline leak detection systems

    Energy Technology Data Exchange (ETDEWEB)

    Baptista, Renan Martins [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. Div. de Explotacao]. E-mail: renan@cenpes.petrobras.com.br

    2000-07-01

    This paper describes a general technical survey on software based leak detection systems (LDS), approaching its main technological features, the operational situations where they are feasible, and the scenarios within the Brazilian pipeline network. The decision on what LDS to choose for a given pipeline is a matter of cost, suitability and feasibility. A simpler low cost, less effective product, but with a fast installation and tuning procedure, may be more suitable for a given operational site (pipeline configuration, kind of fluid, quality of instrumentation and communication), than a complex, high cost, efficient product, but taking a long time to be properly installed. Some other may really have a level of complexity that will require a more sophisticated system. A few number of them will simply not be suitable to have a LDS: it may be caused by the poor quality or absence of instrumentation, or, the worst case, due to the lack of technology to approach that specific case, e. g., multiphase flow lines, or those lines that commonly operates in slack condition. It is intended to approach here the general state-of-the-technique and make some initial comments on the costs. (author)

  2. Deciding between compensated volume balance and real time transient models for pipeline leak detection system

    Energy Technology Data Exchange (ETDEWEB)

    Baptista, Renan Martins [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. Div. de Explotacao]. E-mail: renan@cenpes.petrobras.com.br

    2000-07-01

    This paper describes a technical procedure to assess a software based leak detection system (LDS), by deciding between a simpler low cost, less effective product, having a fast installation and tuning, and a complex one with high cost and efficiency, which however takes a long time to be properly installed. This is a common decision among the pipeline operating companies, considering that the majority of the lines are short, with single phase liquid flow (which may include batches), basic communication system and instrumentation. Service companies offer realistic solutions for liquid flow, but usually designed to big pipeline networks, flowing multiple batches and allowing multiple fluid entrances and deliveries. Those solutions are sometimes impractical to short pipelines, due to its high cost, as well as long tuning procedures, complex instrumentation, communication and computer requirements. It is intended to approach here the best solution according to its cost. In a practical sense, it means to differentiate the various LDS techniques. Those techniques are available in a considerable number, and they are still spreading, according to the different scenarios. However, two most known and worldwide implemented techniques hold the majority of the market: the Compensated Volume Balance (CVB), which is less accurate, reliable and robust, but cheaper, simpler and faster to install, and the Real Time Transient Model (RTTM), which is very reliable, accurate and robust, but expensive and complex. This work will describe a way to define whether one can use or not a CVB in a pipeline. (author)

  3. 340 Facility Secondary Containment and Leak Detection Project W-302 Functional Design Criteria

    Energy Technology Data Exchange (ETDEWEB)

    Stordeur, R.T.

    1995-03-01

    This functional design criteria for the upgrade to the 340 radioactive liquid waste storage facility (Project W-302) specifically addresses the secondary containment issues at the current vault facility of the 340 Complex. This vault serves as the terminus for the Radioactive Liquid Waste System (RLWS). Project W-302 is necessary in order to bring this portion of the Complex into full regulatory compliance. The project title, ``340 Facility Secondary Containment and Leak Detection``, illustrates preliminary thoughts of taking corrective action directly upon the existing vault (such as removing the tanks, lining the vault, and replacing tanks). However, based on the conclusion of the engineering study, ``Engineering Study of the 300 Area Process Wastewater Handling System``, WHC-SD-WM-ER-277 (as well as numerous follow-up meetings with cognizant staff), this FDC prescribes a complete replacement of the current tank/vault system. This offers a greater array of tanks, and provides greater operating flexibility and ease of maintenance. This approach also minimizes disruption to RLWS services during ``tie-in``, as compared to the alternative of trying to renovate the old vault. The proposed site is within the current Complex area, and maintains the receipt of RLWS solutions through gravity flow.

  4. AIRBORNE, OPTICAL REMOTE SENSING OF METHANE AND ETHANE FOR NATURAL GAS PIPLINE LEAK DETECTION

    Energy Technology Data Exchange (ETDEWEB)

    Jerry Myers

    2004-05-12

    Ophir Corporation was awarded a contract by the U. S. Department of Energy, National Energy Technology Laboratory under the Project Title ''Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipeline Leak Detection'' on October 14, 2002. The third six-month technical report contains a summary of the progress made towards finalizing the design and assembling the airborne, remote methane and ethane sensor. The vendor has been chosen and is on contract to develop the light source with the appropriate linewidth and spectral shape to best utilize the Ophir gas correlation software. Ophir has expanded upon the target reflectance testing begun in the previous performance period by replacing the experimental receiving optics with the proposed airborne large aperture telescope, which is theoretically capable of capturing many times more signal return. The data gathered from these tests has shown the importance of optimizing the fiber optic receiving fiber to the receiving optic and has helped Ophir to optimize the design of the gas cells and narrowband optical filters. Finally, Ophir will discuss remaining project issues that may impact the success of the project.

  5. AIRBORNE, OPTICAL REMOTE SENSING OF METHANE AND ETHANE FOR NATURAL GAS PIPELINE LEAK DETECTION

    Energy Technology Data Exchange (ETDEWEB)

    Jerry Myers

    2003-11-12

    Ophir Corporation was awarded a contract by the U. S. Department of Energy, National Energy Technology Laboratory under the Project Title ''Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipeline Leak Detection'' on October 14, 2002. This second six-month technical report summarizes the progress made towards defining, designing, and developing the hardware and software segments of the airborne, optical remote methane and ethane sensor. The most challenging task to date has been to identify a vendor capable of designing and developing a light source with the appropriate output wavelength and power. This report will document the work that has been done to identify design requirements, and potential vendors for the light source. Significant progress has also been made in characterizing the amount of light return available from a remote target at various distances from the light source. A great deal of time has been spent conducting laboratory and long-optical path target reflectance measurements. This is important since it helps to establish the overall optical output requirements for the sensor. It also reduces the relative uncertainty and risk associated with developing a custom light source. The data gathered from the optical path testing has been translated to the airborne transceiver design in such areas as: fiber coupling, optical detector selection, gas filters, and software analysis. Ophir will next, summarize the design progress of the transceiver hardware and software development. Finally, Ophir will discuss remaining project issues that may impact the success of the project.

  6. 40 CFR 63.1024 - Leak repair.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Leak repair. 63.1024 Section 63.1024... Standards for Equipment Leaks-Control Level 2 Standards § 63.1024 Leak repair. (a) Leak repair schedule. The owner or operator shall repair each leak detected as soon as practical, but not later than 15...

  7. 40 CFR 65.105 - Leak repair.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Leak repair. 65.105 Section 65.105... FEDERAL AIR RULE Equipment Leaks § 65.105 Leak repair. (a) Leak repair schedule. The owner or operator shall repair each leak detected as soon as practical but not later than 15 calendar days after it...

  8. Volumetric Virtual Environments

    Institute of Scientific and Technical Information of China (English)

    HE Taosong

    2000-01-01

    Driven by fast development of both virtual reality and volume visualization, we discuss some critical techniques towards building a volumetric VR system, specifically the modeling, rendering, and manipulations of a volumetric scene.Techniques such as voxel-based object simplification, accelerated volume rendering,fast stereo volume rendering, and volumetric "collision detection" are introduced and improved, with the idea of demonstrating the possibilities and potential benefits of incorporating volumetric models into VR systems.

  9. AIRBORNE, OPTICAL REMOTE SENSING OF METHANE AND ETHANE FOR NATURAL GAS PIPELINE LEAK DETECTION

    Energy Technology Data Exchange (ETDEWEB)

    Jerry Myers

    2003-05-13

    Ophir Corporation was awarded a contract by the U. S. Department of Energy, National Energy Technology Laboratory under the Project Title ''Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipeline Leak Detection'' on October 14, 2002. This six-month technical report summarizes the progress for each of the proposed tasks, discusses project concerns, and outlines near-term goals. Ophir has completed a data survey of two major natural gas pipeline companies on the design requirements for an airborne, optical remote sensor. The results of this survey are disclosed in this report. A substantial amount of time was spent on modeling the expected optical signal at the receiver at different absorption wavelengths, and determining the impact of noise sources such as solar background, signal shot noise, and electronic noise on methane and ethane gas detection. Based upon the signal to noise modeling and industry input, Ophir finalized the design requirements for the airborne sensor, and released the critical sensor light source design requirements to qualified vendors. Responses from the vendors indicated that the light source was not commercially available, and will require a research and development effort to produce. Three vendors have responded positively with proposed design solutions. Ophir has decided to conduct short path optical laboratory experiments to verify the existence of methane and absorption at the specified wavelength, prior to proceeding with the light source selection. Techniques to eliminate common mode noise were also evaluated during the laboratory tests. Finally, Ophir has included a summary of the potential concerns for project success and has established future goals.

  10. Development of a fiber-optic sensor for hydrogen leak detection

    Energy Technology Data Exchange (ETDEWEB)

    Benson, D.K.; Tracy, C.E. [National Renewable Energy Lab., Golden, CO (United States)

    1995-09-01

    The real and perceived risks of hydrogen fuel use, particularly in passenger vehicles, will require extensive safety precautions including hydrogen leak detection. Conventional hydrogen gas sensors require electrical wiring and may be too expensive for deployment in multiple locations within a vehicle. In this recently initiated project, we are attempting to develop a reversible, thin-film, chemochromic sensor that can be applied to the end of a polymer optical fiber. The presence of hydrogen gas causes the film to become darker. A light beam transmitted from a central instrument in the vehicle along the sensor fibers will be reflected from the ends of the fiber back to individual light detectors. A decrease in the reflected light signal will indicate the presence and concentration of hydrogen in the vicinity of the fiber sensor. The typical thin film sensor consists of a layer of transparent, amorphous tungsten oxide covered by a very thin reflective layer of palladium. When the sensor is exposed to hydrogen, a portion of the hydrogen is dissociated, diffuses through the palladium and reacts with the tungsten oxide to form a blue insertion compound, H{sub X}WO{sub 3}- When the hydrogen gas is no longer present, the hydrogen will diffuse out of the H{sub X}WO{sub 3} and oxidize at the palladium/air interface, restoring the tungsten oxide film and the light signal to normal. The principle of this detection scheme has already been demonstrated by scientists in Japan. However, the design of the sensor has not been optimized for speed of response nor tested for its hydrogen selectivity in the presence of hydrocarbon gases. The challenge of this project is to modify the basic sensor design to achieve the required rapid response and assure sufficient selectivity to avoid false readings.

  11. Assessment of Early Leak-Detection Capabilities at a Commercial-Scale Carbon Capture and Storage Site

    Science.gov (United States)

    Williams, M. D.; Vermeul, V. R.; Oostrom, M.; Porse, S.

    2014-12-01

    In cooperation with the U.S. Department of Energy (DOE), a large Midwest carbon capture and storage (CCS) project will upgrade a power plant with oxy-combustion technology to capture approximately 1.1 million metric tons (MMT) of CO2 each year. This project will design and construct a first-of-its-kind, near-zero emissions coal-fueled power plant that incorporates CCS. The project will implement a suite of monitoring technologies that includes early-leak-detection monitoring directly above the primary confining zone in regions of increased leakage potential (e.g., near wells that penetrate the caprock). In support of early leak-detection monitoring systems design, numerical models were developed and used to evaluate the relative value of various leak detection metrics over a range of hypothetical leakage scenarios. This preliminary modeling evaluation was based on a simplified model that assumed uniform properties for each model layer and interrogated both pressure and geochemical response in the first permeable interval overlying the primary confining zone. Simulation results indicate that pressure is likely to be the earliest indicator of leakage, given the rapid and areally extensive nature of this response. Simulated geochemical signals are much more localized and take much longer to develop than the pressure responses. Because of the buoyancy effect associated with supercritical CO2 (scCO2), early leak-detection monitoring for these leakage scenarios would be best achieved through monitoring in the upper portion of the interval near the contact with overlying low-permeability materials. Conversely, monitoring for geochemical signals associated with brine leakage exhibited less lateral spread than for scCO2 cases and detection of leakage would be best achieved through monitoring at the base of the interval. Results from these preliminary models for a suite of leakage scenarios and monitoring location distances will be presented. These preliminary models will be

  12. Infrared hyperspectral tunable filter imaging spectrometer for remote leak detection, chemical speciation, and stack/vent analysis applications

    Science.gov (United States)

    Hinnrichs, Michele

    2002-02-01

    With support from the Department of Energy, the State of California and the Gas Technology Institute, Pacific Advanced Technology is developing a small field portable infrared imaging spectrometer (Sherlock) based on the advances in hyperspectral tunable filter technology, that will be applied to the detection of fugitive gas leaks. This imaging spectrometer uses the Image Multi-spectral Sensing (IMSS) diffractive optic tunable filter invented by Pacific Advanced Technology . The Sherlock has an embedded digital signal processor for real time detection of the gas leak while surrounded by severe background noise. The infrared sensor engine is a 256 x 320 midwave cooled focal plane array which spans the spectral range from 3 to 5 microns, ideal for most hydrocarbon leaks. The technology is by no means limited to this spectral region, and can just as easily work in the longwave infrared from 8 to 12 microns for chemical detection applications. This paper will present the design of the Sherlock camera as well as processed data collected at a gas processing plant and an instrumented kiln at LSU using the prototype camera. The processed data shows that the IMSS imaging spectrometer, using an all passive approach, has the sensitivity to detect methane gas leaks at short range with a flow rate as low as 0.01 scfm2. In addition, the IMSS imaging spectrometer can measure hot gas plumes at longer ranges. As will be shown in this paper the IMSS can detect and image warm species gas additives of methane and propane in the Kiln exhaust stack. The methane injected gas with a concentration of 72 ppm and the propane with a concentration of 49 ppm (as seen by the IMSS sensor) at a range of 60 meters. The atmospheric path was a stressing environment, being hot and humid, for any imaging infrared spectrometer.

  13. An Amplitude-Based Estimation Method for International Space Station (ISS) Leak Detection and Localization Using Acoustic Sensor Networks

    Science.gov (United States)

    Tian, Jialin; Madaras, Eric I.

    2009-01-01

    The development of a robust and efficient leak detection and localization system within a space station environment presents a unique challenge. A plausible approach includes the implementation of an acoustic sensor network system that can successfully detect the presence of a leak and determine the location of the leak source. Traditional acoustic detection and localization schemes rely on the phase and amplitude information collected by the sensor array system. Furthermore, the acoustic source signals are assumed to be airborne and far-field. Likewise, there are similar applications in sonar. In solids, there are specialized methods for locating events that are used in geology and in acoustic emission testing that involve sensor arrays and depend on a discernable phase front to the received signal. These methods are ineffective if applied to a sensor detection system within the space station environment. In the case of acoustic signal location, there are significant baffling and structural impediments to the sound path and the source could be in the near-field of a sensor in this particular setting.

  14. Conceptual design report for the project to install leak detection in FAST-FT-534/548/549

    Energy Technology Data Exchange (ETDEWEB)

    Galloway, K.J.

    1992-07-01

    This report provides conceptual designs and design recommendations for installing secondary containment and leak detection systems for three sumps at the Fluorinel and Storage Facility (FAST), CPP-666. The FAST facility is located at the Idaho Chemical Processing Plant (ICPP) at the Idaho National Engineering Laboratory (INEL). The three sumps receive various materials from the FAST water treatment process. This project involves sump upgrades to meet appropriate environmental requirements. The steps include: providing sump modifications or designs for the installation of leak chases and/or leakage accumulation, coating the sump concrete with a chemical resistant sealant (except for sump VES-FT-534 which is already lined with stainless steel) to act as secondary containment, lining the sumps with a primary containment system, and providing a means to detect and remove primary containment leakage that may occur.

  15. Detection of UCP1 protein and measurements of dependent GDP-sensitive proton leak in non-phosphorylating thymus mitochondria.

    Science.gov (United States)

    Clarke, Kieran J; Carroll, Audrey M; O'Brien, Gemma; Porter, Richard K

    2015-01-01

    Over several years we have provided evidence that uncoupling protein 1 (UCP1) is present in thymus mitochondria. We have demonstrated the conclusive evidence for the presence of UCP1 in thymus mitochondria and we have been able to demonstrate a GDP-sensitive UCP1-dependent proton leak in non-phosphorylating thymus mitochondria. In this chapter, we show how to detect UCP1 in mitochondria isolated from whole thymus using immunoblotting. We show how to measure GDP-sensitive UCP1-dependent oxygen consumption in non-phosphorylating thymus mitochondria and we show that increased reactive oxygen species production occurs on addition of GDP to non-phosphorylating thymus mitochondria. We conclude that reactive oxygen species production rate can be used as a surrogate for detecting UCP1 catalyzed proton leak activity in thymus mitochondria.

  16. Proposed strategy for leak detection, monitoring, and mitigation (LDMM) during Hanford single-shell tank waste retrieval

    Energy Technology Data Exchange (ETDEWEB)

    Iwatate, D.F., Westinghouse Hanford

    1996-07-08

    This document proposes a strategy to address issues related to leakage from single-shell tanks (SSTs) during sluicing. A set of criteria are proposed to capture the relevant issues pertaining to leak detection, monitoring, and mitigation (LDMM), and allow DOE-RL, the Contractor, Ecology, and Hanford Stakeholders to reach consensus on allowable leakage volumes (ALVs). Technical studies and findings that support the proposed strategy, and ALV criteria, are summarized and referenced. This document specifically addresses LDMM for SSTs at Hanford, Washington.

  17. Effect of anatomical backgrounds on detectability in volumetric cone beam CT images

    Science.gov (United States)

    Han, Minah; Park, Subok; Baek, Jongduk

    2016-03-01

    As anatomical noise is often a dominating factor affecting signal detection in medical imaging, we investigate the effects of anatomical backgrounds on signal detection in volumetric cone beam CT images. Signal detection performances are compared between transverse and longitudinal planes with either uniform or anatomical backgrounds. Sphere objects with diameters of 1mm, 5mm, 8mm, and 11mm are used as the signals. Three-dimensional (3D) anatomical backgrounds are generated using an anatomical noise power spectrum, 1/fβ, with β=3, equivalent to mammographic background [1]. The mean voxel value of the 3D anatomical backgrounds is used as an attenuation coefficient of the uniform background. Noisy projection data are acquired by the forward projection of the uniform and anatomical 3D backgrounds with/without sphere lesions and by the addition of quantum noise. Then, images are reconstructed by an FDK algorithm [2]. For each signal size, signal detection performances in transverse and longitudinal planes are measured by calculating the task SNR of a channelized Hotelling observer with Laguerre-Gauss channels. In the uniform background case, transverse planes yield higher task SNR values for all sphere diameters but 1mm. In the anatomical background case, longitudinal planes yield higher task SNR values for all signal diameters. The results indicate that it is beneficial to use longitudinal planes to detect spherical signals in anatomical backgrounds.

  18. Implementation of leak detection techniques in ducts with critical regimen multiphase flow; Implementacao de tecnicas de deteccao de vazamentos em dutos em regime de escoamento multifasico critico

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Rodrigo S.; Maitelli, Andr L.; Doria Neto, Adriao D.; Salazar, Andres O. [Rio Grande do Norte Univ., Natal, RN (Brazil)

    2005-07-01

    This paper presents signals processing techniques and artificial neural networks to identify leaks in multiphase flow pipeline. The greatest difficulty on traditional methods of leak detection (volume balance, pressure point analysis, etc) is that they are insufficient to design an adequate profile for the real conditions of oil pipeline transport. These difficult conditions goes since unevenly soil, that cause columns or vacuum throughout pipelines, until the presence of multi phases like water, gas and oil; plus other components as sand, which use to produce discontinuous flow off and diverse variations. To attenuate these difficulties, the transform wavelet was used to map the signal pressure in different resolution plan allowing the extraction of descriptors that identify leaks patterns and with then to provide training for the neural network multilayer perceptron (MLP) to learning of how to classify this pattern and report whenever this characterize leaks. During the tests were used transient and regime signals and pipelines with punctures with size variations from 1/2'' to 1'' of diameter to simulate leaks and, this way, it was possible to detect leaks with a time window of two minutes. The result show that the proposed descriptors considered, based in statistical methods applied in domain transform, are sufficient to identify leaks patterns and make it possible to train the neural classifier to indicate the occurrence of pipeline leaks. (author)

  19. DETECTION OF HISTORICAL PIPELINE LEAK PLUMES USING NON-INTRUSIVE SURFACE-BASED GEOPHYSICAL TECHNIQUES AT THE HANFORD NUCLEAR SITE WASHINGTON USA

    Energy Technology Data Exchange (ETDEWEB)

    SKORSKA MB; FINK JB; RUCKER DF; LEVITT MT

    2010-12-02

    Historical records from the Department of Energy Hanford Nuclear Reservation (in eastern WA) indicate that ruptures in buried waste transfer pipelines were common between the 1940s and 1980s, which resulted in unplanned releases (UPRs) of tank: waste at numerous locations. A number of methods are commercially available for the detection of active or recent leaks, however, there are no methods available for the detection of leaks that occurred many years ago. Over the decades, leaks from the Hanford pipelines were detected by visual observation of fluid on the surface, mass balance calculations (where flow volumes were monitored), and incidental encounters with waste during excavation or drilling. Since these detection methods for historic leaks are so limited in resolution and effectiveness, it is likely that a significant number of pipeline leaks have not been detected. Therefore, a technology was needed to detect the specific location of unknown pipeline leaks so that characterization technologies can be used to identify any risks to groundwater caused by waste released into the vadose zone. A proof-of-concept electromagnetic geophysical survey was conducted at an UPR in order to image a historical leak from a waste transfer pipeline. The survey was designed to test an innovative electromagnetic geophysical technique that could be used to rapidly map the extent of historical leaks from pipelines within the Hanford Site complex. This proof-of-concept test included comprehensive testing and analysis of the transient electromagnetic method (TEM) and made use of supporting and confirmatory geophysical methods including ground penetrating radar, magnetics, and electrical resistivity characterization (ERC). The results for this initial proof-of-concept test were successful and greatly exceeded the expectations of the project team by providing excellent discrimination of soils contaminated with leaked waste despite the interference from an electrically conductive pipe.

  20. A survey and description of candidate technologies to support single shell tank waste retrieval, leak detection, monitoring, and mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, R.E.; Teel, S.S.; Wegener, W.H.; Iwatate, D.F.

    1995-09-01

    This report was initially designed to provide a comprehensive review of potential leak detection technologies (LDTs). To this end, the report would contain several sections outlining the selection process. The purpose was twofold:(l) the reader would have a clear understanding of why specific technologies were recommended or not recommended, and (2) the reader could apply the same process in the future as new LDTs become available. Curtailment of project scope has prevented the development of the requisite judging criteria. The report has been modified accordingly. Section 2 of this report presents the baseline and guiding assumptions that were used to judge the LDTs. These assumptions include the environment where the technologies would be employed, the potential leak detection targets, and anticipated leak mechanisms. Section 3 presents a brief review of the methods used to arrive at the recommended LDTs. It also includes a description of the different technology families considered. Section 4 presents the recommended LDTs along with detailed descriptions of each that include sensitivities, operating parameters, and costs.

  1. 75 FR 4134 - Pipeline Safety: Leak Detection on Hazardous Liquid Pipelines

    Science.gov (United States)

    2010-01-26

    ... safety study on pipeline Supervisory Control and Data Acquisition (SCADA) systems (NTSB/SS-05/02). The... indications of a leak on the SCADA interface was the impetus for this study. The NTSB examined 13 hazardous... large pipeline breaks. The line balance processes incorporating SCADA or other technology are geared...

  2. A Small Leak Detection Method Based on VMD Adaptive De-Noising and Ambiguity Correlation Classification Intended for Natural Gas Pipelines

    Directory of Open Access Journals (Sweden)

    Qiyang Xiao

    2016-12-01

    Full Text Available In this study, a small leak detection method based on variational mode decomposition (VMD and ambiguity correlation classification (ACC is proposed. The signals acquired from sensors were decomposed using the VMD, and numerous components were obtained. According to the probability density function (PDF, an adaptive de-noising algorithm based on VMD is proposed for noise component processing and de-noised components reconstruction. Furthermore, the ambiguity function image was employed for analysis of the reconstructed signals. Based on the correlation coefficient, ACC is proposed to detect the small leak of pipeline. The analysis of pipeline leakage signals, using 1 mm and 2 mm leaks, has shown that proposed detection method can detect a small leak accurately and effectively. Moreover, the experimental results have shown that the proposed method achieved better performances than support vector machine (SVM and back propagation neural network (BP methods.

  3. A Small Leak Detection Method Based on VMD Adaptive De-Noising and Ambiguity Correlation Classification Intended for Natural Gas Pipelines.

    Science.gov (United States)

    Xiao, Qiyang; Li, Jian; Bai, Zhiliang; Sun, Jiedi; Zhou, Nan; Zeng, Zhoumo

    2016-12-13

    In this study, a small leak detection method based on variational mode decomposition (VMD) and ambiguity correlation classification (ACC) is proposed. The signals acquired from sensors were decomposed using the VMD, and numerous components were obtained. According to the probability density function (PDF), an adaptive de-noising algorithm based on VMD is proposed for noise component processing and de-noised components reconstruction. Furthermore, the ambiguity function image was employed for analysis of the reconstructed signals. Based on the correlation coefficient, ACC is proposed to detect the small leak of pipeline. The analysis of pipeline leakage signals, using 1 mm and 2 mm leaks, has shown that proposed detection method can detect a small leak accurately and effectively. Moreover, the experimental results have shown that the proposed method achieved better performances than support vector machine (SVM) and back propagation neural network (BP) methods.

  4. Doppler method leak detection for LMFBR steam generators. Pt. 2. Detection characteristics of bubble in-water using large scale SG model

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, Hiromichi [Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan). Komae Research Lab

    2000-06-01

    To prevent the expansion of tube damage and to maintain structural integrity in the steam generators (SGs) of a fast breeder reactor (FBR), it is necessary to detect precisely and immediately the leakage of water from heat transfer tubes. Therefore, an active acoustic method was developed. Previous studies have revealed that, in practical steam generators, the active acoustic method can detect bubbles of 10 l/s within 10 seconds. However to prevent the expansion of damage to neighboring tubes, it is necessary to detect smaller leakages of water from the heat transfer tubes. The Doppler method is designed to detect small leakages and to find the source of a leak before damage spreads to neighboring tubes. The detection sensitivity of the Doppler method and the influence of background noise were investigated experimentally. In-water experiments were performed using an SG full-sector model that simulates actual SGs. The results show that the Doppler method can detect bubbles of 0.1 l/s (equivalent to a water leak rate of about 0.1 g/s) within a few seconds and that the background noise has little effect on water leak detection performance. The Doppler method thus has great potential for the detection of water leakage in SGs. (author)

  5. Leak detection technologies for oil and gas pipelines; Tecnologias para deteccao e localizacao de vazamento em dutos de oleo e ou gas

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, Julio R. [MTT Aselco Automacao Ltda., Sao Paulo, SP (Brazil)

    2005-07-01

    Two concepts are available for leak detection in oil and/or gas pipelines: On-line leak detection system and off-line leak detection technique. The off-line leak detection technique is, usually, portable and does net configure a 'system'. This technique includes hydro-test, acoustic emission of high frequency, tracer of chemical substances, ultrasonic flow meter (UT), thermographic infra-red mapping, electromagnetic offset registration, etc. Since most of those methods requests stop of the system or depend on direct and detailed inspection of the whole monitored piping they are limited to the off-line inspection. In the current days there are only two technologies applied to detect and locate leaks on-line: The acoustic Leak Detection System and the modeling of computerized simulation also called as RTM (Real Time Modeling), RTTM or Mass Balance. There are still other techniques in the market, as acoustic emission, pressure analysis (PPA) beyond other rough techniques, without good results. Even some of these techniques are working without success, they are still used to accomplish with government standards. (author)

  6. High Temperature Humidity Sensor for Detection of Leak Through Slits and Cracks in Pressurized Nuclear Power Reactor Pipes

    Directory of Open Access Journals (Sweden)

    Debdulal Saha

    2007-03-01

    Full Text Available The leak before break (LBB concept is well known to nuclear power reactor. The problem is common to water power reactor. This is based on the premise that a detectable leak will develop before catastrophic break occurs. The main purpose of the present study is to develop tape cast MgCr2O4+35mole% TiO2 and gel cast g-Al2O3 humidity sensor for use in LBB applications at 3000C. The material capacitance varies with transient injection of water vapour adsorption. In actual plant, the sensors are placed on a steam pipe surrounded by heat insulation. The pipe unites the nuclear reactor and power generator. The analysis of humidity distribution in the annulus is calculated assuring leak rate 0.1gpm in a 30 m long tube. In this paper, analysis is done on the basis of the two types of sensor using AC frequency. Performance characteristics are observed for the LLB application.

  7. New methods for leaks detection and localisation using acoustic emission; Nouvelles methodes de detection et de localisation de fuites par emission acoustique

    Energy Technology Data Exchange (ETDEWEB)

    Boulanger, P.

    1993-12-08

    Real time monitoring of Pressurized Water nuclear Reactor secondary coolant system tends to integrate digital processing machines. In this context, the method of acoustic emission seems to exhibit good performances. Its principle is based on passive listening of noises emitted by local micro-displacements inside a material under stress which propagate as elastic waves. The lack of a priori knowledge on leak signals leads us to go deeper into understanding flow induced noise generation. Our studies are conducted using a simple leak model depending on the geometry and the king of flow inside the slit. Detection and localization problems are formulated according to the maximum likelihood principle. For detection, the methods using a indicator of similarity (correlation, higher order correlation) seems to give better results than classical ones (rms value, envelope, filter banks). For leaks location, a large panel of classical (generalized inter-correlation) and innovative (convolution, adaptative, higher order statistics) methods of time delay estimation are presented. The last part deals with the applications of higher order statistics. The analysis of higher order estimators of a non linear non Gaussian stochastic process family, the improvement of non linear prediction performances and the optimal-order choice problem are addressed in simple analytic cases. At last, possible applications to leak signals analysis are pointed out. (authors).264 refs., 7 annexes.

  8. Borehole Volumetric Strainmeters Detect Very Long-period Ocean Level Changes in Tokai Area

    Science.gov (United States)

    Takanami, T.; Linde, A. T.; Sacks, S. I.; Kitagawa, G.; Hirata, N.; Rydelek, P. A.

    2015-12-01

    We detected a clear very long-period strain signal with a predominant period of about 2 months in the data from Sacks-Evertson borehole volumetric strainmeters. These have been operated by the Japan Meteorological Agency (JMA) since 1976 in Tokai area, Japan, the area of an expected Tokai eartquake. Earth's surface is always influenced by natural force such as earth tide, air pressure, and precipitation as well as by human induced sources. In order to decompose into their components in the maximum likelihood estimation, state-space modeling (Takanami et al., 2013) is applied to the observed time series data for 15 months before and after the earthquake M6.5 that occurred on 11th August 2009 in Suruga Bay. In the analysis, the strain data are decomposed into trend, air pressure, earth tide, precipitation effects and observation noise. Clear long-period strain signals are seen in the normalized trend component time series. Time series data from JMA tide gages around Suruga Bay are similarly decomposed. Then spectral analyses are applied to the trend components for the same time interval. Comparison of amplitude peaks in spectra for both data sets show all have a peak at period of about 1464 hours. Thus strain changes may be influenced by very long-period ocean level changes; it is necessary to consider this possibility before attributing tectonic significance to such variations.

  9. Eye-tracking of nodule detection in lung CT volumetric data

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, Ivan; Verdun, Francis R.; Bochud, François O., E-mail: francois.bochud@chuv.ch [Institute of Radiation Physics, Lausanne University Hospital, Lausanne 1004 (Switzerland); Schmidt, Sabine [Department of Radiology, Lausanne University Hospital, Lausanne 1004 (Switzerland)

    2015-06-15

    Purpose: Signal detection on 3D medical images depends on many factors, such as foveal and peripheral vision, the type of signal, and background complexity, and the speed at which the frames are displayed. In this paper, the authors focus on the speed with which radiologists and naïve observers search through medical images. Prior to the study, the authors asked the radiologists to estimate the speed at which they scrolled through CT sets. They gave a subjective estimate of 5 frames per second (fps). The aim of this paper is to measure and analyze the speed with which humans scroll through image stacks, showing a method to visually display the behavior of observers as the search is made as well as measuring the accuracy of the decisions. This information will be useful in the development of model observers, mathematical algorithms that can be used to evaluate diagnostic imaging systems. Methods: The authors performed a series of 3D 4-alternative forced-choice lung nodule detection tasks on volumetric stacks of chest CT images iteratively reconstructed in lung algorithm. The strategy used by three radiologists and three naïve observers was assessed using an eye-tracker in order to establish where their gaze was fixed during the experiment and to verify that when a decision was made, a correct answer was not due only to chance. In a first set of experiments, the observers were restricted to read the images at three fixed speeds of image scrolling and were allowed to see each alternative once. In the second set of experiments, the subjects were allowed to scroll through the image stacks at will with no time or gaze limits. In both static-speed and free-scrolling conditions, the four image stacks were displayed simultaneously. All trials were shown at two different image contrasts. Results: The authors were able to determine a histogram of scrolling speeds in frames per second. The scrolling speed of the naïve observers and the radiologists at the moment the signal

  10. Bayesian belief network for CO2 leak detection by near-surface flux rates for CO2 and perfluorocarbon (PFC) tracer

    Science.gov (United States)

    Yang, Y.; Small, M. J.; Ogretim, E.; Gray, D. D.; Bromhal, G. S.; Strazisar, B. R.; Wells, A. W.

    2010-12-01

    To incorporate the use of multiple geologic sequestration monitoring techniques, a Bayesian Belief Network (BBN) for leak detection inference is applied to integrate the information provided by different techniques deployed at a site. In this study, two monitoring methods, near-surface soil CO2 flux and perfluorocarbon (PFC) tracer concentration, are included in the BBN. First, possible near-surface flux rates for CO2 and PFC tracer as a function of distance from a leakage point are simulated by TOUGH2, given different leakage rates and permeabilities. Then, the natural near-surface CO2 flux and background PFC tracer concentration measured at the Zero Emission Research and Technology (ZERT) site are used to determine critical values for leak inference and to calculate the probabilities of leak detection given a monitoring network. A BBN of leak detection is established by combing the TOUGH2 simulations and the background characterization of near-surface CO2 flux and PFC tracer at the sequestration site. The results show a positive correlation between the detection abilities of PFC tracer and soil CO2 flux, but the PFC tracer is more sensitive for detecting a leak in most cases. The BBN of leak detection including both soil CO2 flux and PFC tracer concentration gives an integrated probability estimation of leak detection for different permeability and leakage rates for a given monitoring network. A BBN developed using the proposed methodology can be used to help site engineers and decision makers to evaluate leakage signals and the risk of undetected leakage, given a suite of monitoring techniques and site conditions.

  11. 1.6 Micron Fiber Laser Source for CH4 Gas Leak Detection

    Directory of Open Access Journals (Sweden)

    Cézard Nicolas

    2016-01-01

    Full Text Available We report on the development of a new pulsed fiber laser source at 1645.5 nm, based on stimulated Raman amplification. This laser source is intended to be used in a future lidar system, dedicated to methane gas leak monitoring in the vicinity of industrial facilities. In this paper we discuss reasons for choosing the 1645.5 nm wavelength, and then we present the two-stage amplification architecture of our fiber laser source under development. Recent experimental results are provided and perspectives are drawn.

  12. 空间站泄漏监测报警方案设想——绝压法%Assumption on Leak Monitoring and Alarming for Space Station --Absolute Pressure Leak Detection

    Institute of Scientific and Technical Information of China (English)

    回天力; 刘刚; 高静; 贾东永; 杨纯; 孙国辉

    2012-01-01

    介绍了各国空间站泄漏监测技术的背景及绝压法泄漏监测的原理,在分析空间站舱体内、外环境的基础上提出了空间站泄漏监测报警模式,及通过测量舱内氮分压进行泄漏监测的技术方案,提出了"反应时间占用率"的概念并以此作为评判监测报警效果的依据,最终对比得出氮分压间接监测法可作为有航天员值守期间空间站的泄漏监测与报警方案。%The background of space station leak monitoring technology and the principle of absolute pressure leak detection are introduced. Based on the analysis of internal and external environment of space station cabin, the monitoring and alarming mode for leak detection is proposed, and the technical scheme of leak monitoring by measuring the partial pressure of nitrogen in the cabin is also introduced. The concept of "Occupation Ratio of Response Time" is put for- ward and taken as a basis for judging the effect of monitoring and alarming. It is concluded that the indirect monitoring method by measuring the partial pressure of nitrogen can be used as a leak monitoring and alarming method when the space station is tended by astronauts.

  13. How Useful is Glucose Detection in Diagnosing Cerebrospinal Fluid Leak? The Rational Use of CT and Beta-2 Transferrin Assay in Detection of Cerebrospinal Fluid Fistula

    Directory of Open Access Journals (Sweden)

    Danny T.M. Chan

    2004-01-01

    Conclusions: Glucose detection using Glucostix test strips is not recommended as a confirmatory test due to its lack of specificity and sensitivity. In the presence of a skull base fracture on CT and a clinical CSF leak, there is no need for a further confirmatory test. In cases where a confirmatory test is needed, the beta-2 transferrin assay is the test of choice because of its high sensitivity and specificity.

  14. 油箱泄漏的超声检测方法%Ultrasonic Leak Detection Methods of Fuel Tank

    Institute of Scientific and Technical Information of China (English)

    薛花; 吴迪; 王亚平; 赵振宁; 陈天夫; 滕永平

    2016-01-01

    The paper analyzed the factors influencing the bubble detection rate in ultrasonic leak detection for fuel tank,studied the characteristics of ultrasonic reflection field of transducer,and proposed a new 8-channel parallel cyclic scanning detection mode, maximizing the repetition frequency of each transducer.Then comparative experiment tests were conducted between our 8-channel parallel ultrasonic leak detector and the traditional one.The results showed that,compared to single-channel scanning mode,the multi-channel parallel testing method had much higher detection rates when the single air bubble or long time interval bubbles needed to be detected.So this method was more effective to detect smaller tank leakage (μm diameter).%分析了影响油箱泄漏超声检测中气泡检出率的相关因素,研究了超声检测探头声场特点,提出了8路并行循环检测的工作模式,最大限度地提高了每个探头的重复工作频率.将自行搭建的8路并行超声波检测装置和传统超声测漏仪器进行了对比试验.结果表明,相对于单路扫描工作方式,多路并行检测对产生时间间隔较大气泡和单个气泡具有较高的检出率,可以检出更微小的缺陷(微米量级).

  15. Results of Tank-Leak Detection Demonstration Using Geophysical Techniques at the Hanford Mock Tank Site-Fiscal Year 2001

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, D BRENT.; Gee, Glendon W.; Sweeney, Mark D.

    2002-03-01

    During July and August of 2001, Pacific Northwest National Laboratory (PNNL), hosted researchers from Lawrence Livermore and Lawrence Berkeley National laboratories, and a private contractor, HydroGEOPHYSICS, Inc., for deployment of the following five geophysical leak-detection technologies at the Hanford Site Mock Tank in a Tank Leak Detection Demonstration (TLDD): (1) Electrical Resistivity Tomography (ERT); (2) Cross-Borehole Electromagnetic Induction (CEMI); (3) High-Resolution Resistivity (HRR); (4) Cross-Borehole Radar (XBR); and (5) Cross-Borehole Seismic Tomography (XBS). Under a ''Tri-party Agreement'' with Federal and state regulators, the U.S. Department of Energy will remove wastes from single-shell tanks (SSTs) and other miscellaneous underground tanks for storage in the double-shell tank system. Waste retrieval methods are being considered that use very little, if any, liquid to dislodge, mobilize, and remove the wastes. As additional assurance of protection of the vadose zone beneath the SSTs, tank wastes and tank conditions may be aggressively monitored during retrieval operations by methods that are deployed outside the SSTs in the vadose zone.

  16. CSF leak

    Science.gov (United States)

    ... 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 ...

  17. Active acoustic leak detection for LMFBR steam generator. Pt. 5. Experiment for detection of bubbles using the SG full sector model

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, Hiromichi [Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan). Komae Research Lab.

    1997-05-01

    In order to prevent the expansion of tube damages and to maintain structural safety in steam generators (SG) of fast breeder reactors (FBR), it is necessary to detect precisely and immediately the leakage of water from tubes of heat exchangers. Therefore, an active acoustic method, which detects the sound attenuation due to bubbles generated in the sodium-water reactions, it being developed. In this paper, the attenuation characteristics of sound attenuated by bubbles and influence of background noise are investigated experimentally by using an SG full sector model (diameter ratio about 1/1, height ratio about 1/7) simulating the actual SG. As an experimental result, the received sound attenuation for ten seconds was more than 10 dB from air bubble injection when injected bubble of 10 l/s (equivalence water leak rate about 10 g/s). The attenuation of sound are least affected by bubble injection position of heat exchanger tube bunch department. And the time was about 25 seconds till the sound attenuation became 10 dB in case of quantity of air bubble 1 l/s (equivalent water leak rate about 1 g/s). It is clarified that the background noise hardly influenced water leak detection performance as a result of having examined influence of background noise. (author)

  18. Elevation profile influence at key contractual performance parameters for LDS (Leak Detection Systems) based on compensated volume balance

    Energy Technology Data Exchange (ETDEWEB)

    Liebenberg, Lieb [TRANSNET Pipeline, Durban (South Africa); Bueno, David; Passos, Rafaela [KANOPUS Consulting, Rio de Janeiro, RJ (Brazil)

    2009-07-01

    This paper describes and discusses procedures and correlations to estimate performance parameters for Leak Detection Systems based on Compensation Volume Balance, at the portions not usually covered by international standards (like, API RP 1130). These parameters include: minimum acceptable leakage to be detected, under steady state conditions, based on flow measurement uncertainty, observed for both pipeline head and tail; an actual flow rate uncertainty against the one informed by the flow meter manufacturer documentation; the reference flow rate for steady state conditions; and the sensitivity one may expect for the system against a given probability of false alarms (i.e., the ways to correlate reliability, the main performance parameter as per API RP 1130 and sensitivity, the second one). A question usually not considered is: how the elevation profile may affect some of these parameters. That is the second main objective addressed herein, with actual examples employed in a South African multi product pipeline. (author)

  19. Semi-empirical AGN detection threshold in spectral synthesis studies of Lyman-continuum-leaking early-type galaxies

    CERN Document Server

    Cardoso, Leandro S M; Papaderos, Polychronis

    2016-01-01

    Various lines of evidence suggest that the cores of a large portion of early-type galaxies (ETGs) are virtually evacuated of warm ionised gas. This implies that the Lyman-continuum (LyC) radiation produced by an assumed active galactic nucleus (AGN) can escape from the nuclei of these systems without being locally reprocessed into nebular emission, which would prevent their reliable spectroscopic classification as Seyfert galaxies with standard diagnostic emission-line ratios. The spectral energy distribution (SED) of these ETGs would then lack nebular emission and be essentially composed of an old stellar component and the featureless power-law (PL) continuum from the AGN. A question that arises in this context is whether the AGN component can be detected with current spectral population synthesis in the optical, specifically, whether these techniques effectively place an AGN detection threshold in LyC-leaking galaxies. To quantitatively address this question, we took a combined approach that involves spectr...

  20. Assessment of Current Inservice Inspection and Leak Monitoring Practices for Detecting Materials Degradation in Light Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Michael T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Simonen, Fredric A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Muscara, Joseph [US Nuclear Regulatory Commission (NRC), Rockville, MD (United States); Doctor, Steven R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kupperman, David S. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-09-01

    An assessment was performed to determine the effectiveness of existing inservice inspection (ISI) and leak monitoring techniques, and recommend improvements, as necessary, to the programs as currently performed for light water reactor (LWR) components. Information from nuclear power plant (NPP) aging studies and from the U. S. Nuclear Regulatory Commission’s Generic Aging Lessons Learned (GALL) report (NUREG-1801) was used to identify components that have already experienced, or are expected to experience, degradation. This report provides a discussion of the key aspects and parameters that constitute an effective ISI program and a discussion of the basis and background against which the effectiveness of the ISI and leak monitoring programs for timely detection of degradation was evaluated. Tables based on the GALL components were used to systematically guide the process, and table columns were included that contained the ISI requirements and effectiveness assessment. The information in the tables was analyzed using histograms to reduce the data and help identify any trends. The analysis shows that the overall effectiveness of the ISI programs is very similar for both boiling water reactors (BWRs) and pressurized water reactors (PWRs). The evaluations conducted as part of this research showed that many ISI programs are not effective at detecting degradation before its extent reached 75% of the component wall thickness. This work should be considered as an assessment of NDE practices at this time; however, industry and regulatory activities are currently underway that will impact future effectiveness assessments. A number of actions have been identified to improve the current ISI programs so that degradation can be more reliably detected.

  1. Methane, Ethane, and Propane Sensor for Real-time Leak Detection and Diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Roscioli, Joseph R. [Aerodyne Research, Inc., Billerica, MA (United States); Herndon, Scott [Aerodyne Research, Inc., Billerica, MA (United States); Nelson, David D. [Aerodyne Research, Inc., Billerica, MA (United States); Yacovitch, Tara [Aerodyne Research, Inc., Billerica, MA (United States)

    2017-03-24

    The Phase I effort demonstrated the technical viability of a fast, sensitive, mobile hydrocarbon monitor. The instrument will enable the oil and gas industry, researchers, and regulators to rapidly identify and chemically profile leaks from facilities. This capability will allow operators to quickly narrow down and mitigate probable leaking equipment, minimizing product loss and penalties due to regulatory non-compliance. During the initial development phase, we demonstrated operation of a prototype monitor that is capable of measuring methane, ethane, and propane at sub-part-per-billion sensitivities in 1 second, using direct absorption infrared spectroscopy. To our knowledge, this is the first instrument capable of fast propane measurements at atmospheric concentrations. In addition, the electrical requirements of the monitor have been reduced from the 1,200 W typical of a spectrometer, to <500 W, making it capable of being powered by a passenger vehicle, and easily deployed by the industry. The prototype monitor leverages recent advances in laser technology, using high-efficiency interband cascade lasers to access the 3 μm region of the mid-infrared, where the methane, ethane, and propane absorptions are strongest. Combined with established spectrometer technology, we have achieved precisions below 200 ppt for each compound. This allows the monitor to measure fast plumes from oil and gas facilities, as well as ambient background concentrations (typical ambient levels are 2 ppm, 1.5 ppb, and 0.7 ppb for methane, ethane and propane, respectively). Increases in instrument operating pressure were studied in order to allow for a smaller 125 W pump to be used, and passive cooling was explored to reduce the cooling load by almost 90% relative to active (refrigerated) cooling. In addition, the simulated infrared absorption profiles of ethane and propane were modified to minimize crosstalk between species, achieving <1% crosstalk between ethane and propane. Finally, a

  2. Leak detection of thermal shield system in EAST cryostat%EAST装置大型低温杜瓦中内外冷屏系统的检漏

    Institute of Scientific and Technical Information of China (English)

    王雅婷; 王小明; 胡建生

    2015-01-01

    针对 EAST 装置大型低温杜瓦中内外冷屏系统存在的泄漏及对外真空室真空度的影响,采用氦质谱负压真空、正压真空及吸枪法相结合的方法,确定了多处泄漏点并分析了泄漏原因,通过修复使EAST外真空室低温运行时的压强﹤1×10-4Pa ,满足了EAST外真空室运行的需要。EAST内外冷屏系统的检漏方法和经验可以运用到大型、复杂的和具有狭小活动空间的真空系统检漏,尤其是对多管道、复杂材料的检漏具有一定的参考价值。%To solve the leakage of thermal shield system in EAST cryostat and its impact on pressure of cryogenic vacuum chamber, we adopted a combination method including vacuum leak detection, pressurized leak detection and sniffer leak detection. We found some leak parts and analyzed the cause of leakage. By mending the thermal shield system, the pressure of the cryogenic vacuum chamber is less than 1×10-4Pa at cryogenic state and meets the need of operation. The method and experience of EAST thermal shield system leak detection can be adopted to large-sized, complicated and narrow space vacuum system. Especially, the method and experience have a certain reference value in the leak detection of multi-pipeline and complicated material vacuum system.

  3. Accuracy improvement in leak detection of charcoal adsorbers by halide pulse integration method

    Energy Technology Data Exchange (ETDEWEB)

    Kovach, B.J.; Banks, E.M. [NUCON International, Inc., Columbus, OH (United States)

    1997-08-01

    Due to the phaseout of the supply of R-11, which is used as a charcoal adsorber leak-testing agent, several new substitutes have been suggested and tested. Pulse testing using agents with higher boiling points produced longer response times (due to prolonged evaporation and dispersion times). This longer evaporation time alters the pulse shape and lowers the peak concentration. Since the dispersion and evaporation time under different ambient condition are unpredictable, the peak concentration becomes unpredictable as well. One way to eliminate this unpredictability is to determine the area under the curve (of concentration versus time) after test-agent injection rather than the peak concentration (height). This value should be independent of the injection time and evaporation rate as long as the volume of the test agent injected remains constant. Thus, tests were performed with a constant volume injection of test agent but with different injection times and evaporation rates. The area under the curve of concentration versus time was then compared with the peak concentration for each injection. 4 refs., 1 fig.

  4. Performance comparison of TDR-based systems for permanent and diffused detection of water content and leaks

    Science.gov (United States)

    Cataldo, A.; De Benedetto, E.; Cannazza, G.; Huebner, C.; Trebbels, D.

    2017-01-01

    In this work, the performance of three time domain reflectometry (TDR) instruments (with different hardware architectures, specifications and costs) is comparatively assessed. The goal is to evaluate the performance of low-cost TDR instrumentation, in view of the development of a completely permanent TDR-based monitoring solution, wherein the costs of the instrument is so low, that it can be left on-site, even unguarded, and controlled remotely. Without losing generality, the applications considered for the comparative experiments are the TDR-based detection of leaks in underground pipes and, more in general, of soil water content variations. For this reason, both laboratory and in-the-field experiments are carried out by comparatively using three TDR instruments, in conjunction with wire-like sensing elements (SEs).

  5. Development of a water leak detection system for LMFBR steam generators. Pt. 2; General planning of sensor arrangement for active acoustic method

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Kazuo; Kumagai, Hiromichi (Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan). Komae Research Lab.)

    1994-04-01

    Development of a water leak detection system with short response time and high sensitivity for LMFBR steam generators is required to prevent failure propagation and to maintain structural integrity of steam generators. A new type of leak detection method, active acoustic method, which observes gas bubbles accompanying the leak using sonic waves is being developed. In this study, some series of experiments are carried out to investigate; (1) attenuation of sonic wave in a typical SG structure, (2) suitable method to attach waveguides to the SG shell, and (3) possibility of reflex method. Furthermore, a reference sensor arrangement for active acoustic method is selected based on the experimental results as the basis of future studies. (author).

  6. Leak Detection for Potable Water Lines at Fort Hood: Final Report on Project AR-F-313 for FY05

    Science.gov (United States)

    2007-06-01

    cables, gas lines, etc., sometimes run close to water pipelines , and it is important to be certain that digging will not cause damage to these...sensors to find leaks in the potable water pipelines of West Fort Hood has been demon- strated to be quite good. Two leaks were discovered during the...the Army consider installing PermaLog permanent leak sensors at other installations where potable water pipelines run in sel- dom traveled areas. The

  7. Detection of active bile leak with Gd-EOB-DTPA enhanced MR cholangiography: Comparison of 20–25 min delayed and 60–180 min delayed images

    Energy Technology Data Exchange (ETDEWEB)

    Cieszanowski, Andrzej, E-mail: andrzej.cieszanowski@wum.edu.pl [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Stadnik, Anna, E-mail: aniaws@yahoo.com [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Lezak, Aleksandra, E-mail: aleksandralezak@gmail.com [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Maj, Edyta, E-mail: em26@wp.pl [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Zieniewicz, Krzysztof, E-mail: krzysztof.zieniewicz@wum.edu.pl [Chair and Department of General, Transplant and Liver Surgery, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Rowinska-Berman, Katarzyna, E-mail: kasiarowinska@wp.pl [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Grudzinski, Ireneusz P., E-mail: ireneusz.grudzinski@wum.edu.pl [Department of Toxicology, Medical University of Warsaw, Faculty of Pharmacy, ul. Banacha 1, 02-097 Warsaw (Poland); Krawczyk, Marek, E-mail: marek.krawczyk@wum.edu.pl [Chair and Department of General, Transplant and Liver Surgery, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Rowiński, Olgierd, E-mail: olgierd.rowinski@wum.edu.pl [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland)

    2013-12-01

    Objectives: The purpose of this study was to assess the value of contrast-enhanced magnetic resonance cholangiography (MRC) performed in different time delays after injection of gadoxetic acid disodium (Gd-EOB-DTPA) for the diagnosis of active bile leak. Methods: This retrospective analysis included Gd-EOB-DTPA enhanced MR images of 34 patients suspected of bile leak. Images were acquired 20–25 min after Gd-EOB-DTPA injection. If there was inadequate contrast in the bile ducts then delayed images after 60–90 min and 150–180 min were obtained. Results were correlated with intraoperative findings, ERCP results, clinical data, laboratory tests, and follow-up examinations. Results: Gd-EOB-DTPA enhanced MRC yielded an overall sensitivity of 96.4%, specificity of 100% and accuracy of 97.1% for the diagnosis of an active bile leak. The sensitivity of 20–25 min delayed MR images was 42.9%, of combined 20–25 min and 60–90 min delayed images was 92.9% and of combined 20–25 min, 60–90 min and 150–180 min delayed images was 96.4%. Conclusions: Gd-EOB-DTPA enhanced MRC utilizing delayed phase images was effective for detecting the presence and location of active bile leaks. The images acquired 60–180 min post-injection enabled identification of bile leaks even in patients with a dilated biliary system or moderate liver dysfunction.

  8. Fundamental study on leak detection of underground gas pipeline using passive acoustic method; Judogata onkyo keisoku ni yoru maisetsu gas dokan hason kasho no kenshutsu ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Jinguji, M.; Imaizumi, H.; Kunimatsu, S.; Isei, T. [National Institute for Resources and Environment, Tsukuba (Japan)

    1997-05-27

    With an objective to detect gas leaking from an underground gas pipeline, discussions have been given on a method which utilizes acoustic characteristics of leakage. On leaking sound generated from damaged portions, the form of damaging was hypothesized as pinholes, and spectra of leaking sounds from holes with different diameters were measured. The dominant frequency decreases as the hole diameter increases, while it is in a region of relatively high frequency of 1 kHz or higher. However, detection from the ground surface was impossible when cover soil has thickness from 0.5 to 1.5 m. In an experiment to measure leaking sound inside the pipe, pressure in the pipe was adjusted to 0.02 atm which is a standard pressure for a low-pressure pipe, and the sound was measured when the hole diameters were varied. In any of the results obtained by varying the hole diameter, spectra having the dominant frequency in the region of 1 kHz or higher were measured. In addition, it was found that sound pressure difference of as much as 50 dB at maximum is generated as compared with a case of no sound leakage. The above results verified that monitoring the high frequency of 1 kHz or higher is effective in detecting leakage from small damages. 2 refs., 4 figs.

  9. Semi-empirical AGN detection threshold in spectral synthesis studies of Lyman-continuum-leaking early-type galaxies

    Science.gov (United States)

    Cardoso, Leandro S. M.; Gomes, Jean-Michel; Papaderos, Polychronis

    2016-10-01

    Various lines of evidence suggest that the cores of a large portion of early-type galaxies (ETGs) are virtually evacuated of warm ionised gas. This implies that the Lyman-continuum (LyC) radiation produced by an assumed active galactic nucleus (AGN) can escape from the nuclei of these systems without being locally reprocessed into nebular emission, which would prevent their reliable spectroscopic classification as Seyfert galaxies with standard diagnostic emission-line ratios. The spectral energy distribution (SED) of these ETGs would then lack nebular emission and be essentially composed of an old stellar component and the featureless power-law (PL) continuum from the AGN. A question that arises in this context is whether the AGN component can be detected with current spectral population synthesis in the optical, specifically, whether these techniques effectively place an AGN detection threshold in LyC-leaking galaxies. To quantitatively address this question, we took a combined approach that involves spectral fitting with Starlight of synthetic SEDs composed of stellar emission that characterises a 10 Gyr old ETG and an AGN power-law component that contributes a fraction 0 ≤ xAGN nuclear activity may be missing in the AGN demographics.

  10. Active acoustic leak detection for LMFBR steam generator. Sound attenuation due to bubbles

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, Hiromichi; Sakuma, Toshio [Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan). Komae Research Lab.

    1995-06-01

    In the steam generators (SG) of LMFBR, it is necessary to detect the leakage of water from tubes of heat exchangers as soon as it occurs. The active acoustic detection method has drawn general interest owing to its short response time and reduction of the influence of background noise. In this paper, the application of the active acoustic detection method for SG is proposed, and sound attenuation by bubbles is investigated experimentally. Furthermore, using the SG sector model, sound field characteristics and sound attenuation characteristics due to injection of bubbles are studied. It is clarified that the sound attenuation depends upon bubble size as well as void fraction, that the distance attenuation of sound in the SG model containing heat transfer tubes is 6dB for each two-fold increase of distance, and that emitted sound attenuates immediately upon injection of bubbles. (author).

  11. Assuring asset integrity through improving the accuracy of leakage source identification of a permanently installed subsea leak detection system using artificial neural networks

    OpenAIRE

    Poungkrajorn, Tawan

    2015-01-01

    Environmental concerns and regulatory controls for oil and gas exploration and production activities have been increasing with the prospecting of deep-water fields and sensitive areas, such as the artic seas. To stop any incidents developing into critical events, subsea leak detection systems are required for a fast, cost-effective, and reasonable accurate method to not only detect the leakage substance (in this case methane), but also to identify its source and location. This thesis evaluate...

  12. Damage in Concrete and its Detection by Use of Stress-Volumetric Strain Diagram

    Directory of Open Access Journals (Sweden)

    Jerga Ján

    2014-05-01

    Full Text Available The reliable determination of the damage degree of concrete in the structure is difficult and not seldom short-term compressive strengths are considered as real strengths of concrete. Because the load history of the construction is generally unknown, we do not know, whether there have been reached values in the vicinity of the peak of the stress-strain diagram. The strength at the sustained or repeated loading would be then significantly lower, as obtained from tests performed on intact samples. The diagnostic of concrete damage is impeded by environmental effects, resulting in the anisotropy of the development of micro cracks. The possibility is pointed out to use the characteristics of the stress volumetric strain diagram for the assessment of the condition of the material, with the perspective of the application for the determination of the residual long-term strength of concrete

  13. Glutathione Modified Gold Nanoparticles for Sensitive Colorimetric Detection of Pb(2+) Ions in Rainwater Polluted by Leaking Perovskite Solar Cells.

    Science.gov (United States)

    Yu, Yaming; Hong, Ying; Gao, Peng; Nazeeruddin, Mohammad Khaja

    2016-12-20

    In the past few years, the advent of lead halide perovskite solar cells (PSCs) has revolutionized the prospects of the third- generation photovoltaics and the reported power conversion efficiency (PCE) has been updated to 22%. Nevertheless, two main challenges, including the poisonous content of Pb and the vexing instability toward water, still lie between the lab-based PSCs technology and large scale commercialization. With this background, we first evaluated Pb(2+) concentration from the rainwater samples polluted by three types of markets promising PSCs with inductively coupled plasma mass spectrometry measurements (ICP-MS) as a case study. The influence of possible conditions (pH value and exposure time) on the contents of Pb(2+) from the three PSCs was systematically compared and discussed. Furthermore, an optimized glutathione functionalized gold nanoparticles (GSH-AuNPs) colorimetric sensing assay was used to determine Pb(2+) leaking from PSCs for the first time. The Pb(2+)-induced aggregation of sensing assay could be monitored via both naked eye and UV-vis spectroscopy with a detection limit of 15 and 13 nM, which are all lower than the maximum level in drinking water permitted by WHO. The quantitative detection results were compared and in good agreement with that of ICP-MS. The results indicate that the content of Pb(2+) from three PSCs are in the same order of magnitude under various conditions. By the use of the prepared GSH-AuNPs self-assembled sensing assay, the fast and on-site detection of Pb(2+) from PSCs can be realized.

  14. Early tube leak detection system for steam boiler at KEV power plant

    Directory of Open Access Journals (Sweden)

    Ismail Firas B.

    2016-01-01

    Full Text Available Tube leakage in boilers has been a major contribution to trips which eventually leads to power plant shut downs. Training of network and developing artificial neural network (ANN models are essential in fault detection in critically large systems. This research focusses on the ANN modelling through training and validation of real data acquired from a sub-critical boiler unit. The artificial neural network (ANN was used to develop a compatible model and to evaluate the working properties and behaviour of boiler. The training and validation of real data has been applied using the feed-forward with back-propagation (BP. The right combination of number of neurons, number of hidden layers, training algorithms and training functions was run to achieve the best ANN model with lowest error. The ANN was trained and validated using real site data acquired from a coal fired power plant in Malaysia. The results showed that the Neural Network (NN with one hidden layers performed better than two hidden layer using feed-forward back-propagation network. The outcome from this study give us the best ANN model which eventually allows for early detection of boiler tube leakages, and forecast of a trip before the real shutdown. This will eventually reduce shutdowns in power plants.

  15. Multi-Spectral imaging of vegetation for detecting CO2 leaking from underground

    Energy Technology Data Exchange (ETDEWEB)

    Rouse, J.H.; Shaw, J.A.; Lawrence, R.L.; Lewicki, J.L.; Dobeck, L.M.; Repasky, K.S.; Spangler, L.H.

    2010-06-01

    Practical geologic CO{sub 2} sequestration will require long-term monitoring for detection of possible leakage back into the atmosphere. One potential monitoring method is multi-spectral imaging of vegetation reflectance to detect leakage through CO{sub 2}-induced plant stress. A multi-spectral imaging system was used to simultaneously record green, red, and near-infrared (NIR) images with a real-time reflectance calibration from a 3-m tall platform, viewing vegetation near shallow subsurface CO{sub 2} releases during summers 2007 and 2008 at the Zero Emissions Research and Technology field site in Bozeman, Montana. Regression analysis of the band reflectances and the Normalized Difference Vegetation Index with time shows significant correlation with distance from the CO{sub 2} well, indicating the viability of this method to monitor for CO{sub 2} leakage. The 2007 data show rapid plant vigor degradation at high CO{sub 2} levels next to the well and slight nourishment at lower, but above-background CO{sub 2} concentrations. Results from the second year also show that the stress response of vegetation is strongly linked to the CO{sub 2} sink-source relationship and vegetation density. The data also show short-term effects of rain and hail. The real-time calibrated imaging system successfully obtained data in an autonomous mode during all sky and daytime illumination conditions.

  16. Portable Dual-comb Spectrometer for Stable Detection of Methane Leaks over Kilometer Scale Paths at Oil and Natural Gas Production Site

    Science.gov (United States)

    Coburn, S.; Wright, R.; Cossel, K.; Truong, G. W.; Baumann, E.; Coddington, I.; Newbury, N.; Alden, C. B.; Ghosh, S.; Prasad, K.; Rieker, G. B.

    2016-12-01

    Newly proposed EPA regulations on volatile organic compound (VOC) emissions from oil and gas production facilities have been expanded to include methane, making the detection of this important trace gas a topic of growing interest to the oil and gas industry, regulators, and the scientific community in general. Reliable techniques that enable long-term monitoring of entire production facilities are needed in order to fully characterize the temporal and spatial trends of emissions from these sites. Recent advances in the development of compact and robust fiber frequency combs are enabling the use of this powerful spectroscopic tool outside of the laboratory, presenting opportunities for kilometer-scale open-path sensing of emissions at remote locations. Here we present the characterization and field deployment of a dual comb spectrometer (DCS) system with the potential to locate and size methane leaks from oil and gas production sites from long range. The DCS is a laser-based system that enables broad spectral absorption measurements (>50 nm) with high spectral resolution (locations near Boulder, CO, demonstrating sensitivities of better than 2 ppb-km for methane. In addition, path integrated methane measurements from the DCS are coupled with an atmospheric inversion utilizing local meteorology and a high resolution fluid dynamics simulation to determine leak location and also derive a leak rate from simulated methane leaks

  17. Investigating vegetation spectral reflectance for detecting hydrocarbon pipeline leaks from multispectral data

    Science.gov (United States)

    Adamu, Bashir; Tansey, Kevin; Bradshaw, Michael J.

    2013-10-01

    The aim of this paper is to analyse spectral reflectance data from Landsat TM of vegetation that has been exposed to hydrocarbon contamination from oil spills from pipelines. The study is undertaken in an area of mangrove and swamp vegetation where the detection of an oil spill is traditionally difficult to make. We used a database of oil spill records to help identify candidate sites for spectral analysis. Extracted vegetation spectra were compared between polluted and nonpolluted sites and supervised (neural network) classification was carried out to map hydrocarbon (HC) contaminated sites from the sample areas. Initial results show that polluted sites are characterised by high reflectance in the visible (VIS) 0.4μm - 0.7μm, and a lower reflectance in the near-infrared (NIR) 0.7μm - 1.1μm. This suggests that the vegetation is in a stressed state. Samples taken from pixels surrounding polluted sites show similar spectral reflectance values to that of polluted sites suggesting possible migration of HC to the wider environment. Further work will focus on increasing the sample size and investigating the impact of an oil spill on a wider buffer zone around the spill site.

  18. Research and development for the high-temperature helium-leak detection system (Joint research). Part 2. Development of temperature sensors using optical fibre for the HTTR

    Energy Technology Data Exchange (ETDEWEB)

    Sakaba, Nariaki; Nakazawa, Toshio; Kawasaki, Kozo [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Urakami, Masao; Saisyu, Sadanori [Japan Atomic Power Co., Tokyo (Japan)

    2003-03-01

    In the second stage of the research and development for a high-temperature helium-leak detection system, the temperature sensor using optical fibres was studied. The sensor detects the helium leakage by the temperature increase surrounded optical fibre with or without heat insulator. Moreover, the applicability of high temperature equipments as the HTTR system was studied. With the sensor we detected 5.0-20.0 cm{sup 3}/s helium leakages within 60 minutes. Also it was possible to detect earlier when the leakage level is at 20.0 cm {sup 3}/s. (author)

  19. NRC Job Code V6060: Extended in-situ and real time monitoring. Task 4: Detection and monitoring of leaks at nuclear power plants external to structures

    Energy Technology Data Exchange (ETDEWEB)

    Sheen, S. H. (Nuclear Engineering Division)

    2012-08-01

    In support of Task 4 of the NRC study on compliance with 10 CFR part 20.1406, minimization of contamination, Argonne National Laboratory (ANL) conducted a one-year scoping study, in concert with a parallel study performed by NRC/NRR staff, on monitoring for leaks at nuclear power plants (NPPs) external to structures. The objective of this task-4 study is to identify and assess those sensors and monitoring techniques for early detection of abnormal radioactive releases from the engineered facility structures, systems and components (SSCs) to the surrounding underground environment in existing NPPs and planned new reactors. As such, methods of interest include: (1) detection of anomalous water content of soils surrounding SSCs, (2) radionuclides contained in the leaking water, and (3) secondary signals such as temperature. ANL work scope includes mainly to (1) identify, in concert with the nuclear industry, the sensors and techniques that have most promise to detect radionuclides and/or associated chemical releases from SSCs of existing NPPs and (2) review and provide comments on the results of the NRC/NRR staff scoping study to identify candidate technologies. This report constitutes the ANL deliverable of the task-4 study. It covers a survey of sensor technologies and leak detection methods currently applied to leak monitoring at NPPs. The survey also provides a technology evaluation that identifies their strength and deficiency based on their detection speed, sensitivity, range and reliability. Emerging advanced technologies that are potentially capable of locating releases, identifying the radionuclides, and estimating their concentrations and distributions are also included in the report along with suggestions of required further research and development.

  20. An automatic algorithm for detecting stent endothelialization from volumetric optical coherence tomography datasets

    Energy Technology Data Exchange (ETDEWEB)

    Bonnema, Garret T; Barton, Jennifer K [College of Optical Sciences, University of Arizona, Tucson, AZ (United States); Cardinal, Kristen O' Halloran [Biomedical and General Engineering, California Polytechnic State University (United States); Williams, Stuart K [Cardiovascular Innovation Institute, University of Louisville, Louisville, KY 40292 (United States)], E-mail: barton@u.arizona.edu

    2008-06-21

    Recent research has suggested that endothelialization of vascular stents is crucial to reducing the risk of late stent thrombosis. With a resolution of approximately 10 {mu}m, optical coherence tomography (OCT) may be an appropriate imaging modality for visualizing the vascular response to a stent and measuring the percentage of struts covered with an anti-thrombogenic cellular lining. We developed an image analysis program to locate covered and uncovered stent struts in OCT images of tissue-engineered blood vessels. The struts were found by exploiting the highly reflective and shadowing characteristics of the metallic stent material. Coverage was evaluated by comparing the luminal surface with the depth of the strut reflection. Strut coverage calculations were compared to manual assessment of OCT images and epi-fluorescence analysis of the stented grafts. Based on the manual assessment, the strut identification algorithm operated with a sensitivity of 93% and a specificity of 99%. The strut coverage algorithm was 81% sensitive and 96% specific. The present study indicates that the program can automatically determine percent cellular coverage from volumetric OCT datasets of blood vessel mimics. The program could potentially be extended to assessments of stent endothelialization in native stented arteries.

  1. An automatic algorithm for detecting stent endothelialization from volumetric optical coherence tomography datasets

    Science.gov (United States)

    Bonnema, Garret T.; O'Halloran Cardinal, Kristen; Williams, Stuart K.; Barton, Jennifer K.

    2008-06-01

    Recent research has suggested that endothelialization of vascular stents is crucial to reducing the risk of late stent thrombosis. With a resolution of approximately 10 µm, optical coherence tomography (OCT) may be an appropriate imaging modality for visualizing the vascular response to a stent and measuring the percentage of struts covered with an anti-thrombogenic cellular lining. We developed an image analysis program to locate covered and uncovered stent struts in OCT images of tissue-engineered blood vessels. The struts were found by exploiting the highly reflective and shadowing characteristics of the metallic stent material. Coverage was evaluated by comparing the luminal surface with the depth of the strut reflection. Strut coverage calculations were compared to manual assessment of OCT images and epi-fluorescence analysis of the stented grafts. Based on the manual assessment, the strut identification algorithm operated with a sensitivity of 93% and a specificity of 99%. The strut coverage algorithm was 81% sensitive and 96% specific. The present study indicates that the program can automatically determine percent cellular coverage from volumetric OCT datasets of blood vessel mimics. The program could potentially be extended to assessments of stent endothelialization in native stented arteries.

  2. Detection of cerebral involvement in patients with active neuropsychiatric systemic lupus erythematosus by the use of volumetric magnetization transfer imaging.

    Science.gov (United States)

    Bosma, G P; Rood, M J; Huizinga, T W; de Jong, B A; Bollen, E L; van Buchem, M A

    2000-11-01

    To determine whether volumetric magnetization transfer imaging (MTI) histogram analysis can detect abnormalities in patients with active neuropsychiatric systemic lupus erythematosus (NPSLE) and to compare the MTI findings in patients with active NPSLE, chronic NPSLE, and multiple sclerosis (MS), as well as in normal control subjects. Eight female and 1 male patient with active nonthromboembolic NPSLE (mean +/- SD age 39 +/- 9 years), 10 female patients with chronic NPSLE (age 33 +/- 11 years), 10 female patients with SLE and no history of NPSLE (non-NPSLE; age 34 +/- 11 years), 10 female patients with inactive MS (age 41 +/- 6 years), and 10 healthy control subjects (age 33 +/- 11 years) underwent MTL. Using the MTI scans, histograms were composed from which we derived a variety of parameters that quantitatively reflect the uniformity of the brain parenchyma as well as the ratio of cerebrospinal fluid to intracranial volume, which reflects atrophy. The magnetization transfer ratio (MTR) histograms in the non-NPSLE group and the healthy control group were similar, whereas those in the chronic NPSLE and MS groups were flatter. There was also flattening of the histograms in the active NPSLE group, but with a shift toward higher MTRs. Our results indicate that volumetric MTI analysis detects cerebral changes in the active phase of NPSLE. The abnormalities in the brain parenchyma of patients with chronic NPSLE produced MTI values that were the same as those in patients with inactive MS. MTI values in the active phase of NPSLE differed from those in the chronic phase, which might reflect the presence of inflammation. These preliminary results suggest that MTI might provide evidence for the presence of active NPSLE. MTI might also prove to be a valuable technique for monitoring treatment trials.

  3. Test Plan for the Demonstration of Geophysical Techniques for Single-Shell Tank Leak Detection at the Hanford Mock Tank Site: Fiscal Year 2001

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, D. Brent; Gee, Glendon W.; Sweeney, Mark D.

    2001-07-31

    As part of the Leak Detection, Monitoring and Mitigation (LDMM) program conducted by CH2M HILL 105-A during FY 2001. These tests are being conducted to assess the applicability of these methods (Electrical Resistance Tomography [ERT], High Resolution Resistivity [HRR], Cross-Borehole Seismography [XBS], Cross-Borehole Radar [XBR], and Cross-Borehole Electromagnetic Induction [CEMI]) to the detection and measurement of Single Shell Tank (SST) leaks into the vadose zone during planned sluicing operations. The testing in FY 2001 will result in the selection of up to two methods for further testing in FY 2002. In parallel with the geophysical tests, a Partitioning Interwell Tracer Test (PITT) study will be conducted simultaneously at the Mock Tank to assess the effectiveness of this technology in detecting and quantifying tank leaks in the vadose zone. Preparatory and background work using Cone Penetrometer methods (CPT) will be conducted at the Mock Tank site and an adjacent test area to derive soil properties for groundtruthing purposes for all methods.

  4. Field tests and commercialization of natural gas leak detectors

    Energy Technology Data Exchange (ETDEWEB)

    Choi, D.S.; Jeon, J.S.; Kim, K.D.; Cho, Y.A. [R and D Center, Korea Gas Corporation, Ansan (Korea)

    1999-09-01

    Objectives - (1) fields test of industrial gas leak detection monitoring system. (2) commericialization of residential gas leak detector. Contents - (1) five sets of gas leak detection monitoring system were installed at natural gas transmition facilities and tested long term stability and their performance. (2) improved residential gas leak detector was commercialised. Expected benefits and application fields - (1) contribution to the improvement of domestic gas sensor technology. (2) localization of fabrication technology for gas leak detectors. 23 refs., 126 figs., 37 tabs.

  5. A volumetric meter chip for point-of-care quantitative detection of bovine catalase for food safety control.

    Science.gov (United States)

    Cui, Xingye; Hu, Jie; Choi, Jane Ru; Huang, Yalin; Wang, Xuemin; Lu, Tian Jian; Xu, Feng

    2016-09-07

    A volumetric meter chip was developed for quantitative point-of-care (POC) analysis of bovine catalase, a bioindicator of bovine mastitis, in milk samples. The meter chip displays multiplexed quantitative results by presenting the distance of ink bar advancement that is detectable by the naked eye. The meter chip comprises a poly(methyl methacrylate) (PMMA) layer, a double-sided adhesive (DSA) layer and a glass slide layer fabricated by the laser-etching method, which is typically simple, rapid (∼3 min per chip), and cost effective (∼$0.2 per chip). Specially designed "U shape" reaction cells are covered by an adhesive tape that serves as an on-off switch, enabling the simple operation of the assay. As a proof of concept, we employed the developed meter chip for the quantification of bovine catalase in raw milk samples to detect catalase concentrations as low as 20 μg/mL. The meter chip has great potential to detect various target analytes for a wide range of POC applications.

  6. Dimensionality aspects of nano micro integrated metal oxide based early stage leak detection room temperature hydrogen sensor

    Science.gov (United States)

    Deshpande, Sameer Arun

    Detection of explosive gas leaks such as hydrogen (H2) becomes key element in the wake of counter-terrorism threats, introduction of hydrogen powered vehicles and use of hydrogen as a fuel for space explorations. In recent years, a significant interest has developed on metal oxide nanostructured sensors for the detection of hydrogen gas. Gas sensors properties such as sensitivity, selectivity and response time can be enhanced by tailoring the size, the shape, the structure and the surface of the nanostructures. Sensor properties (sensitivity, selectivity and response time) are largely modulated by operating temperature of the device. Issues like instability of nanostructures at high temperature, risk of hydrogen explosion and high energy consumption are driving the research towards detection of hydrogen at low temperatures. At low temperatures adsorption of O2- species on the sensor surface instead of O- (since O- species reacts easily with hydrogen) result in need of higher activation energy for hydrogen and adsorbed species interaction. This makes hydrogen detection at room temperature a challenging task. Higher surface area to volume ratio (resulting higher reaction sites), enhanced electronic properties by varying size, shape and doping foreign impurities (by modulating space charge region) makes nanocrystalline materials ideal candidate for room temperature gas sensing applications. In the present work various morphologies of nanostructured tin oxide (SnO 2) and indium (In) doped SnO2 and titanium oxide (titania, TiO2) were synthesized using sol-gel, hydrothermal, thermal evaporation techniques and successfully integrated with the micro-electromechanical devices H2 at ppm-level (as low as 100ppm) has been successfully detected at room temperature using the SnO2 nanoparticles, SnO2 (nanowires) and TiO2 (nanotubes) based MEMS sensors. While sensor based on indium doped tin oxide showed the highest sensitivity (S =Ra/Rg= 80000) and minimal response time (10sec

  7. Non-invasive detection of biliary leaks using Gd-EOB-DTPA-enhanced MR cholangiography: comparison with T2-weighted MR cholangiography

    Energy Technology Data Exchange (ETDEWEB)

    Kantarci, Mecit; Pirimoglu, Berhan; Bayraktutan, Ummugulsum; Ogul, Hayri; Kizrak, Yesim; Eren, Suat [Atatuerk University, School of Medicine, Department of Radiology, Erzurum (Turkey); Karabulut, Nevzat [Pamukkale University, School of Medicine, Department of Radiology, Denizli (Turkey); Ozturk, Gurkan; Aydinli, Bulent [Atatuerk University, School of Medicine, Department of General Surgery, Erzurum (Turkey); Yilmaz, Sinan [Atatuerk University, School of Medicine, Department of Public Health, Erzurum (Turkey)

    2013-10-15

    To evaluate the added role of T1-weighted (T1w) gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance cholangiography (MRC) compared with T2-weighted MRC (T2w-MRC) in the detection of biliary leaks. Ninety-nine patients with suspected biliary complications underwent routine T2w-MRC and T1w contrast-enhanced (CE) MRC using Gd-EOB-DTPA to identify biliary leaks. Two observers reviewed the image sets separately and together. MRC findings were compared with those of surgery and percutaneous transhepatic cholangiopancreatography. The sensitivity, specificity and accuracy of the techniques in identifying biliary leaks were calculated. Accuracy of locating biliary leaks was superior with the combination of Gd-EOB-DTPA-enhanced MRC and T2w-MRC (P < 0.05).The mean sensitivities were 79 % vs 59 %, and the mean accuracy rates were 84 % vs 58 % for combined CE-MRC and T2w-MRC vs sole T2w-MRC. Nineteen out of 21 patients with biliary-cyst communication, 90.4 %, and 12/15 patients with post-traumatic biliary extravasations, 80 %, were detected by the combination of Gd-EOB-DTPA-enhanced MRC and T2w-MRC images, P < 0.05. Gd-EOB-DTPA-enhanced MRC yields information that complements T2w-MRC findings and improves the identification and localisation of the bile extravasations (84 % accuracy, 100 % specificity, P < 0.05). We recommend Gd-EOB-DTPA-enhanced MRC in addition to T2w-MRC to increase the preoperative accuracy of identifying and locating extravasations of bile. (orig.)

  8. Photoacoustic Detection of Perfluorocarbon Tracers in Air for Application to Leak Detection in Oil-Filled Cables

    Science.gov (United States)

    Zajarevich, N.; Slezak, V.; Peuriot, A.; Villa, G.; Láttero, A.; Crivicich, R.

    2013-09-01

    The underground oil-filled cable consists of a hollow copper conductor surrounded by oiled paper which acts as electrical insulation. The oil flows along the conductor and diffuses through it to the insulating paper. A lead sheath is used as the outer retaining wall. As the deterioration of this cover may cause a loss of insulation fluid, its detection is very important since this high voltage and power cable is used in cities even under sidewalks. The method of perfluorocarbon vapor tracers, based on the injection and subsequent detection of these volatile chemical substances in the vicinity of the cable, is one of the most promising methods, so far used in combination with gas chromatography and mass spectrometry. In this study, the possibility of detecting two different tracers, and , by means of resonant photoacoustic spectroscopy is studied. The beam from a tunable amplitude-modulated laser goes through an aluminum cell with quarter wave filters at both ends of an open resonator and an electret microphone in its center, attached to the walls. The calibration of the system for either substance diluted in chromatographic air showed a higher sensitivity for , so the experiment was completed checking the behavior of this substance in samples prepared with ambient air in order to analyze the application of the system to field studies.

  9. JavaScript 中的内存泄漏检测方法研究磁%An Approach to Detection Memory Leak in JavaScript

    Institute of Scientific and Technical Information of China (English)

    孙琳; 洪玫; 詹聪; 杜伊; 张琼宇

    2015-01-01

    As a mainstream front‐end script language ,JavaScript is widely used in WEB applications .Although dynam‐ic memory management for JavaScript is to use automatic management methods ,it still has memory leak problem because of the use of all kinds of libraries .In this paper ,11 kinds of memory leak patterns are analyzed and summarized ,it put forward combining the dynamic and static detection methods ,which implements the 11 kinds of memory leak detection .For static de‐tection ,abstract syntax tree is created based on JavaScript program ,relationship between class and event is analyzed and ab‐stracted ,object execution trajectory is tracked ,the suspected leak objects are found .For dynamic detection ,according to the result of static detection ,test cases are generated and ran ,dynamic heap information is gotten ,type points‐from graph is cre‐ated ,memory leaks is judged by analyzing rising trend of memory usage rate .This memory leak detection method is feasible by experimental verification ,performing well ,which reduces false positives compared with static detection and increases cov ‐erage rate compared with dynamic detection .%JavaScript 作为一种主流的前端脚本语言,广泛运用于 Web 应用中。虽然 JavaScript 语言具有垃圾回收机制动态管理内存,但用于各类程序库的的运用,仍然存在内存泄漏的问题。论文分析和归纳了十一种内存泄漏的模式,并提出静态和动态的检测方法的结合,实现对十一种内存泄漏的检测。在静态检测中,基于 JavaScript 程序的抽象语法树,分析和抽象类和事件之间的关系,跟踪对象执行轨迹,发现疑似泄漏的对象。在动态检测阶段,依据静态检测结果,生成测试用例并运行,获取动态堆信息,构建类型指向图,通过分析内存占用率上升的趋势判断内存泄漏。实验验证本内存泄漏检测方法是可行性的,并有较好的检测能力,比较

  10. Variable leak gas source

    Science.gov (United States)

    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. WHIRL WIND DETECTION AND IDENTIFICATION IN INDONESIA UTILIZING SINGLE POLARIZATION DOPPLER WEATHER RADAR VOLUMETRIC DATA

    Directory of Open Access Journals (Sweden)

    A. Ali

    2016-06-01

    Full Text Available Whirl wind occurrence frequency in Indonesia tends increasing in the last five years. Geospatial data from National Agency for Disaster Management (BNPB recorded 72 cases with the impact of the two victims died, ten injured, 485 people were evacuated, and 1285 buildings were destroyed at period of January-June 2015. Based on the impact, early warning through remote sensing by using single polarization Doppler weather radar is need to be efforted. Whirl wind detection is done by identifying the characteristic pattern of the rotating convective cloud system by hook echo, analyzing the exsistance of vortex and rotation, and the strength of turbulence. The results show horizontal wind profile with a rotational pattern at CAPPI (V and HWIND (V by the altitude of 0.5 km, strong turbulence through product CAPPI (W 0.5 km ranged of 1.75-2.05 ms-1, the vertical wind profile by product VVP (V with a maximum value updraft reaches more than 20 knots at a 100-200 meters height, strong horizontal wind shear through HSHEAR (V and CAPPI (HSHEAR altitude of 0.5 km with a range of 6.23 to 10.12 ms-1/km. SWI and SSA show that the cloud base height is very low ranged from 200-600 meters with a maximum reflectivity reached 61.5 dBZ by top cloud height reached 14 km, while the product CAPPI (Z 0.5 km and CMAX (Z is very difficult to identify patterns hook echo. The results of remote sensing are very representative with the physical properties of whirl wind even whirl wind in a smaller scale.

  12. Whirl Wind Detection and Identification in Indonesia Utilizing Single Polarization Doppler Weather Radar Volumetric Data

    Science.gov (United States)

    Ali, Abdullah; Hidayati, Sabitul

    2016-06-01

    Whirl wind occurrence frequency in Indonesia tends increasing in the last five years. Geospatial data from National Agency for Disaster Management (BNPB) recorded 72 cases with the impact of the two victims died, ten injured, 485 people were evacuated, and 1285 buildings were destroyed at period of January-June 2015. Based on the impact, early warning through remote sensing by using single polarization Doppler weather radar is need to be efforted. Whirl wind detection is done by identifying the characteristic pattern of the rotating convective cloud system by hook echo, analyzing the exsistance of vortex and rotation, and the strength of turbulence. The results show horizontal wind profile with a rotational pattern at CAPPI (V) and HWIND (V) by the altitude of 0.5 km, strong turbulence through product CAPPI (W) 0.5 km ranged of 1.75-2.05 ms-1, the vertical wind profile by product VVP (V) with a maximum value updraft reaches more than 20 knots at a 100-200 meters height, strong horizontal wind shear through HSHEAR (V) and CAPPI (HSHEAR) altitude of 0.5 km with a range of 6.23 to 10.12 ms-1/km. SWI and SSA show that the cloud base height is very low ranged from 200-600 meters with a maximum reflectivity reached 61.5 dBZ by top cloud height reached 14 km, while the product CAPPI (Z) 0.5 km and CMAX (Z) is very difficult to identify patterns hook echo. The results of remote sensing are very representative with the physical properties of whirl wind even whirl wind in a smaller scale.

  13. In-pipe leak detection by Minimum Residual complexity: A Robust time Delay Estimation method against correlated noise

    CERN Document Server

    Ahmadi, A M; Bahrampour, A R; Ravanbod, H

    2013-01-01

    In this work, the residual complexity (RC) similarity measure, is employed for time delay estimation (TDE) in gas pipe leak localization. The result of TDE by RC is compared with those of Cross Correlation(CC) and Mutual Information(MI) similarity measures based on our experimental data. The comparison confirms the advantages of RC relative to CC and MI, in robustness against both correlated noises and reduction of number of samples. These advantages originate from not only its mathematical nature of RC similarity measure which considers interdependency but also from broadband frequency of acoustic waves propagating during gas pipes.

  14. Locating a leaking crack by safe stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, C.E.; Sagat, S. (Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.); Shek, G.K.; Graham, D.B.; Durand, M.A. (Ontario Hydro, Toronto, ON (Canada))

    1990-01-01

    A few Zr-2.5 Nb alloy pressure tubes in CANDU nuclear reactors have leaked through cracks that have grown by delayed hydride cracking (DHC). In some instances, tubes contained confirmed leaks that were leaking at a rate too low for precise identification of the leaking channel. Controlled stimulation of DHC can be used to help locate these leaks by extending the crack and increasing the leak rate without approaching crack instability. In the event of a leak being detected, a plant operator can gain time for leak location by a heating and unloading manoeuvre that will arrest crack growth and increase the critical crack length. This manoeuvre increases the safety margin against tube rupture. If required, the operator can then stimulate cracking in a controlled manner to aid in leak identification. Sequences of temperature and load manoeuvres for safe crack stimulation have been found by laboratory tests on dry specimens and the efficacy of the process has been demonstrated, partly in a power reactor, and partly in a full-scale simulation of a leaking pressure tube. (author).

  15. Active standoff detection of CH4 and N2O leaks using hard-target backscattered light using an open-path quantum cascade laser sensor

    Science.gov (United States)

    Diaz, Adrian; Thomas, Benjamin; Castillo, Paulo; Gross, Barry; Moshary, Fred

    2016-05-01

    Fugitive gas emissions from agricultural or industrial plants and gas pipelines are an important environmental concern as they contribute to the global increase of greenhouse gas concentrations. Moreover, they are also a security and safety concern because of possible risk of fire/explosion or toxicity. This study presents standoff detection of CH4 and N2O leaks using a quantum cascade laser open-path system that retrieves path-averaged concentrations by collecting the backscattered light from a remote hard target. It is a true standoff system and differs from other open-path systems that are deployed as point samplers or long-path transmission systems that use retroreflectors. The measured absorption spectra are obtained using a thermal intra-pulse frequency chirped DFB quantum cascade laser at ~7.7 µm wavelength range with ~200 ns pulse width. Making fast time resolved observations, the system simultaneously realizes high spectral resolution and range to the target, resulting in path-averaged concentration retrieval. The system performs measurements at high speed ~15 Hz and sufficient range (up to 45 m, ~148 feet) achieving an uncertainty of 3.1 % and normalized sensitivity of 3.3 ppm m Hz-1/2 for N2O and 9.3 % and normalized sensitivity of 30 ppm m Hz-1/2 for CH4 with a 0.31 mW average power QCL. Given these characteristics, this system is promising for mobile or multidirectional search and remote detection of gas leaks.

  16. Active Stand-off Detection of Gas Leaks Using a Short Range Hard-target Backscatter Differential Optical Absorption System Based on a Quantum Cascade Laser Transmitter

    Science.gov (United States)

    Diaz, Adrian; Thomas, Benjamin; Castillo, Paulo; Gross, Barry; Moshary, Fred

    2016-06-01

    Fugitive gas emissions from agricultural or industrial plants and gas pipelines are an important environmental concern as they can contribute to the global increase of greenhouse gas concentration. Moreover, they are also a security and safety concern because of possible risk of fire/explosion or toxicity. This study presents gas concentration measurements using a quantum cascade laser open path system (QCLOPS). The system retrieves the pathaveraged concentration of N2O and CH4 by collecting the backscattered light from a scattering target. The gas concentration measurements have a high temporal resolution (68 ms) and are achieved at sufficient range (up to 40 m, ~ 130 feet) with a detection limit of 2.6 ppm CH4 and 0.4 ppm for N2O. Given these characteristics, this system is promising for mobile/multidirectional remote detection and evaluation of gas leaks. The instrument is monostatic with a tunable QCL emitting at ~ 7.7 μm wavelength range. The backscattered radiation is collected by a Newtonian telescope and focused on an infrared light detector. Puffs of N2O and CH4 are released along the optical path to simulate a gas leak. The measured absorption spectrum is obtained using the thermal intra-pulse frequency chirped DFB QCL and is analyzed to obtain path averaged gas concentrations.

  17. Design and experimentation of a bell-mouthed spray gun with two channels for helium leak detection%一种氦质谱检漏用双流道喷枪的设计及实验

    Institute of Scientific and Technical Information of China (English)

    冯晓; 廖旭东; 胡茂中; 白国云; 陈涛

    2012-01-01

    To solve the problem of inaccurate positioning of leak by usual spray gun during the leak detection, a bell-mouthed spay gun with two channels was designed and the corresponding experiment was also carried out. The results show that the bell-mouthed spray gun with two channels can differentiate the two leaks 15mm apart and the positioning range of single leak is Φ20mm, which improves the accuracy of leak positioning during helium leak detection.%为解决普通喷枪在检漏时对漏孔定位能力低的问题,设计了一种钟罩式双流道喷枪,并对其开展了测试实验.结果表明:喷氦法检漏时,利用钟罩式双流道喷枪可分辨出相距15mm的相邻漏孔,对单一漏孔定位范围为Φ20 mm,较大的提高了喷氦法检漏时对漏孔的定位能力.

  18. On the Acoustic Filtering of the Pipe and Sensor in a Buried Plastic Water Pipe and its Effect on Leak Detection: An Experimental Investigation

    Science.gov (United States)

    Almeida, Fabrício; Brennan, Michael; Joseph, Phillip; Whitfield, Stuart; Dray, Simon; Paschoalini, Amarildo

    2014-01-01

    Acoustic techniques have been used for many years to find and locate leaks in buried water distribution systems. Hydrophones and accelerometers are typically used as sensors. Although geophones could be used as well, they are not generally used for leak detection. A simple acoustic model of the pipe and the sensors has been proposed previously by some of the authors of this paper, and their model was used to explain some of the features observed in measurements. However, simultaneous measurements of a leak using all three sensor-types in controlled conditions for plastic pipes has not been reported to-date and hence they have not yet been compared directly. This paper fills that gap in knowledge. A set of measurements was made on a bespoke buried plastic water distribution pipe test rig to validate the previously reported analytical model. There is qualitative agreement between the experimental results and the model predictions in terms of the differing filtering properties of the pipe-sensor systems. A quality measure for the data is also presented, which is the ratio of the bandwidth over which the analysis is carried out divided by the centre frequency of this bandwidth. Based on this metric, the accelerometer was found to be the best sensor to use for the test rig described in this paper. However, for a system in which the distance between the sensors is large or the attenuation factor of the system is high, then it would be advantageous to use hydrophones, even though they are invasive sensors. PMID:24658622

  19. On the Acoustic Filtering of the Pipe and Sensor in a Buried Plastic Water Pipe and its Effect on Leak Detection: An Experimental Investigation

    Directory of Open Access Journals (Sweden)

    Fabrício Almeida

    2014-03-01

    Full Text Available Acoustic techniques have been used for many years to find and locate leaks in buried water distribution systems. Hydrophones and accelerometers are typically used as sensors. Although geophones could be used as well, they are not generally used for leak detection. A simple acoustic model of the pipe and the sensors has been proposed previously by some of the authors of this paper, and their model was used to explain some of the features observed in measurements. However, simultaneous measurements of a leak using all three sensor-types in controlled conditions for plastic pipes has not been reported to-date and hence they have not yet been compared directly. This paper fills that gap in knowledge. A set of measurements was made on a bespoke buried plastic water distribution pipe test rig to validate the previously reported analytical model. There is qualitative agreement between the experimental results and the model predictions in terms of the differing filtering properties of the pipe-sensor systems. A quality measure for the data is also presented, which is the ratio of the bandwidth over which the analysis is carried out divided by the centre frequency of this bandwidth. Based on this metric, the accelerometer was found to be the best sensor to use for the test rig described in this paper. However, for a system in which the distance between the sensors is large or the attenuation factor of the system is high, then it would be advantageous to use hydrophones, even though they are invasive sensors.

  20. Dual-tree complex wavelet transform and SVD based acoustic noise reduction and its application in leak detection for natural gas pipeline

    Science.gov (United States)

    Yu, Xuchao; Liang, Wei; Zhang, Laibin; Jin, Hao; Qiu, Jingwei

    2016-05-01

    During the last decades, leak detection for natural gas pipeline has become one of the paramount concerns of pipeline operators and researchers across the globe. However, acoustic wave method has been proved to be an effective way to identify and localize leakage for gas pipeline. Considering the fact that noises inevitably exist in the acoustic signals collected, noise reduction should be enforced on the signals for subsequent data mining and analysis. Thus, an integrated acoustic noise reduction method based on DTCWT and SVD is proposed in this study. The method is put forward based on the idea that noise reduction strategy should match the characteristics of the noisy signal. According to previous studies, it is known that the energy of acoustic signals collected under leaking condition is mainly concentrated in low-frequency portion (0-100 Hz). And ultralow-frequency component (0-5 Hz), which is taken as the characteristic frequency band in this study, can propagate a relatively longer distance and be captured by sensors. Therefore, in order to filter the noises and to reserve the characteristic frequency band, DTCWT is taken as the core to conduct multilevel decomposition and refining for acoustic signals and SVD is employed to eliminate noises in non-characteristic bands. Both simulation and field experiments show that DTCWT-SVD is an excellent method for acoustic noise reduction. At the end of this study, application in leakage localization shows that it becomes much easier and a little more accurate to estimate the location of leak hole after noise reduction by DTCWT-SVD.

  1. Sample Delivery and Computer Control Systems for Detecting Leaks in the Main Engines of the Space Shuttle

    Science.gov (United States)

    Griffin, Timothy P.; Naylor, Guy R.; Hritz, Richard J.; Barrett, Carolyn A.

    1997-01-01

    The main engines of the Space Shuttle use hydrogen and oxygen as the fuel and oxidant. The explosive and fire hazards associated with these two components pose a serious danger to personnel and equipment. Therefore prior to use the main engines undergo extensive leak tests. Instead of using hazardous gases there tests utilize helium as the tracer element. This results in a need to monitor helium in the ppm level continuously for hours. The major challenge in developing such a low level gas monitor is the sample delivery system. This paper discuss a system developed to meet the requirements while also being mobile. Also shown is the calibration technique, stability, and accuracy results for the system.

  2. Active stand-off detection of gas leaks using an open-path quantum cascade laser sensor in a backscatter configuration

    Science.gov (United States)

    Diaz, Adrian; Thomas, Benjamin; Castillo, Paulo; Gross, Barry; Moshary, Fred

    2005-05-01

    Fugitive gas emissions from agricultural or industrial plants and gas pipelines are an important environmental concern as they can contribute to the global increase of greenhouse gas concentration. Moreover, they are also a security and safety concern because of possible risk of fire/explosion or toxicity. This study presents gas concentration measurements using a quantum cascade laser open path system (QCLOPS). The system retrieves the path-averaged concentration of N2O by collecting the backscattered light from a scattering target. The gas concentration measurements have a high temporal resolution (68 ms) and are achieved at sufficient range (up to 40 m, ~ 130 feet) with a detection limit of 0.4 ppm for N2O. Given these characteristics, this system is promising for mobile/multidirectional remote detection and evaluation of gas leaks.

  3. Performance evaluation of PFBR wire type sodium leak detectors

    Energy Technology Data Exchange (ETDEWEB)

    Vijayakumar, G., E-mail: viju@igcar.gov.in [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Rajan, K.K.; Nashine, B.K.; Chandramouli, S. [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Madhusoodanan, K. [Reactor Engineering Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Kalyanasundaram, P. [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

    2011-06-15

    Highlights: > Performance evaluation of wire type leak detectors was conducted in LEENA facility by creating sodium leaks. > The lowest leak rate of 214 g/h was detected in 50 min and the highest detection time was 6 h for a leak rate of 222 g/h. > Factors affecting the leak detection time are packing density of thermal insulation, layout of heater, temperature, etc. > Relationship between leak rate and detection time was established and a leak rate of 100 g/h is likely to be detected in 11.1 h. > Contact resistance of leaked sodium increased to 3.5 kilo ohms in 20 h. - Abstract: Wire type leak detectors working on conductivity principle are used for detecting sodium leak in the secondary sodium circuits of fast breeder reactors. It is required to assess the performance of these detectors and confirm that they are meeting the requirements. A test facility by name LEENA was constructed at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam to test the wire type leak detector lay out by simulating different sodium leak rates. This test facility consists of a sodium dump tank, a test vessel, interconnecting pipelines with valves, micro filter and test section with leak simulators. There are three different test sections in the test set up of length 1000 mm each. These test sections simulate piping of Prototype Fast Breeder Reactor (PFBR) secondary circuit and the wire type leak detector layout in full scale. All test sections are provided with leak simulators. A leak simulator consists of a hole of size one mm drilled in the test section and closed with a tapered pin. The tapered pin position in the hole is adjusted by a screw mechanism and there by the annular gap of flow area is varied for getting different leak rates. Various experiments were conducted to evaluate the performance of the leak detectors by creating different sodium leak rates. This paper deals with the details of wire type leak detector layout for the secondary sodium circuit of PFBR

  4. Volumetric image classification using homogeneous decomposition and dictionary learning: A study using retinal optical coherence tomography for detecting age-related macular degeneration.

    Science.gov (United States)

    Albarrak, Abdulrahman; Coenen, Frans; Zheng, Yalin

    2017-01-01

    Three-dimensional (3D) (volumetric) diagnostic imaging techniques are indispensable with respect to the diagnosis and management of many medical conditions. However there is a lack of automated diagnosis techniques to facilitate such 3D image analysis (although some support tools do exist). This paper proposes a novel framework for volumetric medical image classification founded on homogeneous decomposition and dictionary learning. In the proposed framework each image (volume) is recursively decomposed until homogeneous regions are arrived at. Each region is represented using a Histogram of Oriented Gradients (HOG) which is transformed into a set of feature vectors. The Gaussian Mixture Model (GMM) is then used to generate a "dictionary" and the Improved Fisher Kernel (IFK) approach is used to encode feature vectors so as to generate a single feature vector for each volume, which can then be fed into a classifier generator. The principal advantage offered by the framework is that it does not require the detection (segmentation) of specific objects within the input data. The nature of the framework is fully described. A wide range of experiments was conducted with which to analyse the operation of the proposed framework and these are also reported fully in the paper. Although the proposed approach is generally applicable to 3D volumetric images, the focus for the work is 3D retinal Optical Coherence Tomography (OCT) images in the context of the diagnosis of Age-related Macular Degeneration (AMD). The results indicate that excellent diagnostic predictions can be produced using the proposed framework.

  5. SU-E-I-10: Investigation On Detectability of a Small Target for Different Slice Direction of a Volumetric Cone Beam CT Image

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C; Han, M; Baek, J [Yonsei University, Incheon (Korea, Republic of)

    2015-06-15

    Purpose: To investigate the detectability of a small target for different slice direction of a volumetric cone beam CT image and its impact on dose reduction. Methods: Analytic projection data of a sphere object (1 mm diameter, 0.2/cm attenuation coefficient) were generated and reconstructed by FDK algorithm. In this work, we compared the detectability of the small target from four different backprojection Methods: hanning weighted ramp filter with linear interpolation (RECON 1), hanning weighted ramp filter with Fourier interpolation (RECON2), ramp filter with linear interpolation (RECON 3), and ramp filter with Fourier interpolation (RECON4), respectively. For noise simulation, 200 photons per measurement were used, and the noise only data were reconstructed using FDK algorithm. For each reconstructed volume, axial and coronal slice were extracted and detection-SNR was calculated using channelized Hotelling observer (CHO) with dense difference-of-Gaussian (D-DOG) channels. Results: Detection-SNR of coronal images varies for different backprojection methods, while axial images have a similar detection-SNR. Detection-SNR{sup 2} ratios of coronal and axial images in RECON1 and RECON2 are 1.33 and 1.15, implying that the coronal image has a better detectability than axial image. In other words, using coronal slices for the small target detection can reduce the patient dose about 33% and 15% compared to using axial slices in RECON 1 and RECON 2. Conclusion: In this work, we investigated slice direction dependent detectability of a volumetric cone beam CT image. RECON 1 and RECON 2 produced the highest detection-SNR, with better detectability in coronal slices. These results indicate that it is more beneficial to use coronal slice to improve detectability of a small target in a volumetric cone beam CT image. This research was supported by the MSIP (Ministry of Science, ICT and Future Planning), Korea, under the IT Consilience Creative Program (NIPA-2014-H0201

  6. Detection of leaks for radioactive tracer in marine duct for transport of liquefied petroleum gas; Deteccion de fugas por radiotrazado en ducto marino para transporte de gas LP

    Energy Technology Data Exchange (ETDEWEB)

    Robles P, E. F.; Benitez S, J. A.; Torre O, J. de la; Cruz S, E. de la; Molina, G.; Hernandez C, J. E.; Flores M, J. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e mail: efrp@nuclear.inin.mx

    2008-07-01

    In this work the aplication in the oil industry of the technique of radioactive tracer appears for the detection of internal leaks in a submarine duct that gives service as it lines of receipt of liquefied petroleum gas (Gas LP) located in the Mexican coast of the Pacific Ocean. This system of marine pipe is a consistent arrangement of a duct interior of 0.254 m (10 inches) of nominal diameter (N.D.) of steel to the carbon for cryogenic service ASTM A 333, Grade 6, schedule 30, isolated thermally with foam of polyurethane and shielding in a steel tube to the carbon ASTM A 53 Grade A, of 0.508 m (20 inches) N. D., schedule 20, which is recovered by a ballast encircling of concrete of 0.0508 m (2 inches) of thickness, reinforced with mesh metallic, and that 1315 m runs on the marine stratum to a maximum depth of 12.5 m. For the detection of leaks by radiotracer it was used as tracer the radioactive isotope La-140 produced in the TRIGA Mark III Experimental Reactor of the National Institute of Nuclear Research, starting from stable lanthanum nitrate (La(NO{sub 3}){sub 3} 6H{sub 2}O), with an activity of 100 mCi, the one which after having been made logistics tasks, given very particular sea maneuvers and due to the conditions of the work place, in the interior tube was injected in two subsequent stages to cover both duct senses; from earth and from the marine end respectively, there being used fresh water like transport way and submergible sodium iodide detectors (NaI) for the rake of the La-140. At the end of the journeys of pursuit of the radiotracer, it was determine the presence of three leaks points located in the break area of the marine surf to 360 m, 450 m and 495 m of distance of a reference point located in the beach section named Trap of Devils. (Author)

  7. Detection of JNI Memory Leaks Based on Extended Bytecode%基于中间语言的 JNI内存泄漏检查

    Institute of Scientific and Technical Information of China (English)

    蒋挺宇; 王鹏; 杨述; 褥震; 董渊; 王生原; 嵇智源

    2015-01-01

    JNI技术支持Java与本地C/C++的相互调用,在Android等混合语言实现的系统中有着广泛应用,但语言之间的安全特性差异使其成为安全薄弱环节,现有的分析方法难以处理多语言相互调用产生的安全缺陷。以JNI调用中易产生的内存泄漏为例,开展Java/C++JNI跨语言分析的研究。采用扩展的Java Bytecode(Bytecode倡)指令作为C++语义的解释来消除跨语言分析的障碍。围绕JNI调用中内存泄漏的问题,做了以下3方面工作:1)定义兼容Java/C++语言的分块内存模型;2)基于LLVM/LLJVM ,设计实现了C++到Bytecode倡的翻译策略;3)建立方法调用图,提取方法摘要,利用过程间分析方法检测JNI调用中的内存泄漏。针对具有典型内存泄漏特征的JNI实例翻译检测表明,该工作能够准确检测出Java/C++混合语言中的内存泄漏,对于JNI混合语言编程的理解和漏洞分析具有重要价值。%The Java native interface(JNI)enables Java code running in a Java virtual machine(JVM ) to be called by native code ,but the difference of security features between languages makes it a security weakness ,which cannot be detected by existing analysis methods .Commonly used detection methods are mainly based on the analysis of intermediate language ,w hich is invalid in this JNI case ,since the lack of an intermediate representation to bridge Java and C+ + .This paper analyzes JNI from a Java/C+ + cross‐language perspective and focuses on memory leaks which frequently occur in JNI calls .In order to overcome language barriers ,this paper proposes extended Bytecode (Bytecode* ) instructions as interpretation of C+ + semantics .Our contributions are described as follows :1)Define a block memory model which is compatible with both Java and C+ + ;2) Design translation rules from C+ +to extended Java Bytecode based on LLVM/LLJVM ;3)Construct a method call graph ,extract

  8. CO{sub 2} leak detection in motor car air conditioner components; CO{sub 2}-Lecksuche an Teilen fuer Automobilklimaanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Schopphoff, A. [Pfeiffer Vacuum, Asslar (Germany)

    2005-07-01

    A test chamber is presented which can detect leak rates of < 0,5 g/a in a CO{sub 2} air conditioner. Requirements are: 1. a low CO{sub 2} background, which is achieved by evacuation of a vacuum chamber; 2. a sensitive sensor (mass spectrometer) with equally high sensitivity for all gases. [German] Mit Hilfe der vorgestellten Testkammer lassen sich Leckraten von < 0,5 g/a in einer CO{sub 2}-Klimaanlage detektieren. Voraussetzung sind: 1. ein niedriger CO{sub 2} Untergrund, der in diesem Aufbau durch das Evakuieren einer Vakuumkammer erreicht wird, und 2. ein empfindlicher Sensor, der alle Gase mit gleicher hoher Genauigkeit messen kann (Massenspektrometer).

  9. Leak detection in pipelines based on inverse transient analysis and mixed integer nonlinear programming[Includes the CSCE forum on professional practice and career development : 1. international engineering mechanics and materials specialty conference : 1. international/3. coastal, estuarine and offshore engineering specialty conference : 2. international/8. construction specialty conference

    Energy Technology Data Exchange (ETDEWEB)

    Shamloo, H.; Haghighi, A. [K.N. Toosi Univ. of Technology, Tehran (Iran, Islamic Republic of). Dept. of Civil Engineering

    2009-07-01

    The flow properties of pipes are affected by leaks. Leak detection methods based on hydraulic modelling and real data records aim to find a pipe's leak parameters including their number, location and size. Inverse Transient Analysis (ITA), generally in time domain, is a powerful approach to develop leak detection methods with considerable benefits. This paper introduced an ITA based leak detection method along with a numerical model developed for direct transient analysis of leaks in pipes using method of characteristics (MOC). Transient state flow was generated in pipe and the pressure fluctuations were sampled only at the end valve location. To minimize the effects of unsteadiness and uncertainties due to the numerical modeling and also practical problems caused by water hammer, the downstream end valve was considered to be closed gradually within a long enough time. Then, using the sampled data and a direct transient analysis model, a mixed integer nonlinear program was developed. A mixed genetic algorithm was used in which the binary chromosomes were decoded as mixed integer leak locations and real leak areas. In order to find unknown leak parameters in a pipe, an objective function was defined using the least squares criterion of differences between observed and calculated pressure heads at the valve location. The genetic algorithm was found to be a powerful and easy to use optimization tool to solve complicated mixed integer nonlinear program (MINLP) problems in leak detection. 24 refs., 1 tab., 7 figs.

  10. Design of wide- band gas leak infrared imaging detection system%宽波段气体泄漏红外成像检测系统设计

    Institute of Scientific and Technical Information of China (English)

    李家琨; 顿雄; 金明磊; 金伟其; 王霞; 夏润秋

    2014-01-01

    有毒有害气体的泄漏不仅污染环境,而且威胁人民生命财产安全,世界各国都非常重视快速有效的气体泄漏检测技术的研究和仪器开发。针对这一问题,提出了宽波段气体泄漏红外成像检测系统设计方案,主要包括宽波段红外光学镜头尧子波段滤光片及切换装置尧宽波段非制冷焦平面探测器尧视频处理及系统控制电路等组成部分,充分利用非制冷探测器的无光谱选择特性,结合热图像非均匀性校正和数字细节增强处理算法,实现了对不同种类气体泄漏的高灵敏度检测,提供了适合人眼判断的气体泄漏视频图像显示结果。整个系统具有可检测气体种类多尧检测范围大速度快尧气体泄漏痕迹明显增强尧系统便携性突出尧成本相对较低等特点。%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. To address this issue, a wide- band gas leak IR imaging detection system design was proposed, mainly including wide- band IR optical lens, the sub- band filters and switching device, wide- band Uncooled Focal Plane Array (UFPA) detector, video processing and system control circuit, which takes full advantage of the spectrally non- selective characteristic of the uncooled focal plane array detector. The system can sensitively detect and visualize a considerable number of different kinds of gases, which are not visible to the naked eyes, by using the IR image non-uniformity correction technology and Digital Detail Enhancement (DDE) technology. The resulting gas leak video easy to be observed for the human eye was provided. Many advantages are commendable, such as scanning a wide range simultaneously, locating the leaking source quickly, visualizing the gas plume intuitively, and

  11. Application of Leak Detection and Location Technology Based on Ultrasonic for Manned Spacecraft%基于超声的气体泄漏检测与定位技术在载人航天器中的应用

    Institute of Scientific and Technical Information of China (English)

    马永成; 陈青松

    2009-01-01

    The fundamental principle of leak detection and location technology based on ultrasonic is introduced in this paper.Both portable leak detection equipment and autonomous ultrasonic leak detection and location equipment are introduced,including their system composition,principle and working mode.The application of these equipments for the ISS and Shuttle is introduced.A scheme of ultrasonic leak detection and location that can be used for the space station of China is developed.%介绍了基于超声的气体泄漏检测与定位技术的基本原理;介绍了便携式超声检漏、无线超声自动检漏这两类已有设备的组成、工作原理及其在国际空间站、美国航天飞机上的应用情况.以此为参照,初步提出了一种可用于我国未来空间站建设的气体泄漏检测与定位方案.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  13. Leaking Chaotic Systems

    CERN Document Server

    Altmann, Eduardo G; Tél, Tamás

    2013-01-01

    There are numerous physical situations in which a hole or leak is introduced in an otherwise closed chaotic system. The leak can have a natural origin, it can mimic measurement devices, and it can also be used to reveal dynamical properties of the closed system. In this paper we provide an unified treatment of leaking systems and we review applications to different physical problems, both in the classical and quantum pictures. Our treatment is based on the transient chaos theory of open systems, which is essential because real leaks have finite size and therefore estimations based on the closed system differ essentially from observations. The field of applications reviewed is very broad, ranging from planetary astronomy and hydrodynamical flows, to plasma physics and quantum fidelity. The theory is expanded and adapted to the case of partial leaks (partial absorption/transmission) with applications to room acoustics and optical microcavities in mind. Simulations in the lima .con family of billiards illustrate...

  14. Studied Practices of Helium Mass Spectrometer to Leaking Detection Technology%氦质谱检漏技术的研究与实践

    Institute of Scientific and Technical Information of China (English)

    濮荣强; 黄文平

    2012-01-01

    在氦质谱检漏技术理论的基础上,采用了以微电脑为中心的自动控制技术,提高了氦质谱检漏仪的全自动操作智能化水平.180°非均匀磁场的实现,使离子聚焦更好.通过电子量程切换技术,减少了量程转换时间,扩大了测量范围,对高准确度密封性智能检测系统的实现进行了详细的研究与实践.%Introducing the theoretical basis of helium mass spectrometer to leaking detection technology, the automatic control technology is used here , which improves intelligent level and reduces the range switching time and expands the measuring range with the helps of both 180° non-uniform magnetic field for ion focus and electronic range switching . The paper gives the studied practices to high precision sealed intelligent detection system in detail.

  15. Real time detection of leaks in non-compressible fluid flow systems: a time series approach; Deteccao em tempo real de vazamentos em redes de escoamento para fluidos incompressiveis: uma abordagem em series temporais

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Cesar Augusto Fernandes de [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica. Lab. SDV - Dutos]. E-mail: jlm@eq.ufrj.br

    2002-06-01

    Algorithms were developed for real time detection, estimation and location of leaks in flow systems operating with non-compressible fluids. Process inputs and outputs are assumed to be available by means of field sensing, treated through historical time series reconciliation and storage. The process presented herein was built as a pseudo stationary system for process data generation at the selected variables: nodal pressures, flow rates in pipes and input and output nodes. The procedure consists in generating data series during the occurrence of programmed events and use them during the training of ARX/ARMAX structure MIMO predictors, with constant update. A sudden leak is detected by a statistically significant instant deviation between a group of predictions and the measures of the process associated with the predictors' answers. Once the event is identified, the next step is to locate and estimate its size using another group of predictors trained through simulated process data of known leak events. These predictors use leak parameters (i.e., its location and orifice diameter) as additional inputs so that estimation can be performed in order to predict real answers to the process that are being deviated from the original predictions monitored during the manifestation of the event. (author)

  16. Leak in spiral weld in a 16 inches gas pipeline

    Energy Technology Data Exchange (ETDEWEB)

    Fazzini, Pablo G.; Bona, Jeremias de [GIE S.A., Mar del Plata (Argentina); Otegui, Jose L. [University of Mar del Plata (Argentina)

    2009-07-01

    This paper discusses a failure analysis after a leak in the spiral weld of a 16 inches natural gas pipeline, in service since 1974. The leak was the result of the coalescence of two different defects, on each surface of the pipe wall, located in the center of the inner cord of the helical DSAW weld. Fractographic and metallographic studies revealed that the leak was a combination of three conditions. During fabrication of the pipe, segregation in grain boundary grouped in mid weld. During service, these segregations underwent a process of selective galvanic corrosion. One of these volumetric defects coincided with a tubular pore in the outer weld. Pigging of the pipeline in 2005 for cleaning likely contributed to the increase of the leak flow, when eliminating corrosion product plugs. Although these defects are likely to repeat, fracture mechanics shows that a defect of this type is unlikely to cause a blowout. (author)

  17. Creation of an Exergetic Based Leak Detection and Diagnosis Methodology for Automotive Carbon Dioxide Air Conditioning Systems

    Directory of Open Access Journals (Sweden)

    M. B. Bailey

    2010-03-01

    Full Text Available

    Carbon dioxide automotive air conditioning (AC systems have been under development for over a decade. Although the AC system construction is important, a reliable refrigerant leakage detection system is also vital. A detailed thermodynamic simulation model and fault detection and diagnosis (FDD system, with proposed validation plans, has been developed at Rochester Institute of Technology. A discussion of simulation models that have been developed for various compressors and heat exchangers is presented; they are compared to actual AC systems to develop a realistic experimental setup. Assumptions from previous work are examined and improved.

    • Portions of this paper were previously published in the ECOS'05 and ECOS'07 conference proceedings.

  18. ALIBABA, an assistance system for the detection of confinement leaks in a PWR reactor; ALIBABA, un systeme d`aide a la detection des voies de fuites du confinement sur un reacteur a eau sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Bedier, P.O.; Libmann, M. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Mecanique et de Technologie

    1995-12-31

    The objective of the Crisis Technical Center (CTC) of the French Institute for Nuclear Protection and Safety (IPSN) is to estimates the consequences of a given nuclear accident on the populations and the environment. ALIBABA is a data processing tool available at the CTC and devoted to the detection of confinement leaks in 900 MWe PWR reactors using the activity values measured by the captors of the installation. The heart of this expert system is a structural and functional representation of the different components directly involved in the leak detection (isolating valves, ventilation systems, electric boards etc..). This tool can manage the availability of each component to make qualitative and quantitative balance-sheets. This paper presents the ALIBABA software, an industrial prototype realized with the SPIRAL knowledge base systems generator at the CEA Reactor Studies and Applied Mathematics Service (SERMA) and commercialized by CRIL-Ingenierie Society. It describes the techniques used for the modeling of PWR systems and for the visualization of the survey. The functionality of the man-machine interface is discussed and the means used for the validation of the software are summarized. (J.S.). 6 refs.

  19. Localization of a continuous CO2 leak from an isotropic flat-surface structure using acoustic emission detection and near-field beamforming techniques

    Science.gov (United States)

    Yan, Yong; Cui, Xiwang; Guo, Miao; Han, Xiaojuan

    2016-11-01

    Seal capacity is of great importance for the safety operation of pressurized vessels. It is crucial to locate the leak hole timely and accurately for reasons of safety and maintenance. This paper presents the principle and application of a linear acoustic emission sensor array and a near-field beamforming technique to identify the location of a continuous CO2 leak from an isotropic flat-surface structure on a pressurized vessel in the carbon capture and storage system. Acoustic signals generated by the leak hole are collected using a linear high-frequency sensor array. Time-frequency analysis and a narrow-band filtering technique are deployed to extract effective information about the leak. The impacts of various factors on the performance of the localization technique are simulated, compared and discussed, including the number of sensors, distance between the leak hole and sensor array and spacing between adjacent sensors. Experiments were carried out on a laboratory-scale test rig to assess the effectiveness and operability of the proposed method. The results obtained suggest that the proposed method is capable of providing accurate and reliable localization of a continuous CO2 leak.

  20. Leak detection method for in-orbit spacecraft using circular ultrasonic sensor array%基于圆形超声阵列传感器的在轨泄漏定位方法

    Institute of Scientific and Technical Information of China (English)

    孟冬辉; 闫荣鑫; 郭欣

    2011-01-01

    In view of more and more debris in space, it is an important issue to locate the leak point in manned spacecraft cabin. In this paper, a leak detection method is developed for spacecraft on orbit using circular ultrasonic array sensors. The time difference of the ultrasonic signal reaching different ultrasonic units is calculated by cross correlation, and then the direction of the leak is determined. The leak location can then be identified by triangulation with three ultrasonic array sensors.%随着空间碎片数量的不断增加,载人航天器在轨泄漏定位问题成为一个亟待解决的问题.文章研究了一种基于圆形超声阵列传感器的在轨泄漏定位方法,利用互相关原理计算泄漏超声信号传播到不同测试单元的时间差,从而确定泄漏所在的方向,并根据三角定位方法确定漏孔的具体位置.

  1. Computer-aided detection of colonic polyps with level set-based adaptive convolution in volumetric mucosa to advance CT colonography toward a screening modality

    Science.gov (United States)

    Zhu, Hongbin; Duan, Chaijie; Pickhardt, Perry; Wang, Su; Liang, Zhengrong

    2009-01-01

    As a promising second reader of computed tomographic colonography (CTC) screening, the computer-aided detection (CAD) of colonic polyps has earned fast growing research interest. In this paper, we present a CAD scheme to automatically detect colonic polyps in CTC images. First, a thick colon wall representation, ie, a volumetric mucosa (VM) with several voxels wide in general, was segmented from CTC images by a partial-volume image segmentation algorithm. Based on the VM, we employed a level set-based adaptive convolution method for calculating the first- and second-order spatial derivatives more accurately to start the geometric analysis. Furthermore, to emphasize the correspondence among different layers in the VM, we introduced a middle-layer enhanced integration along the image gradient direction inside the VM to improve the operation of extracting the geometric information, like the principal curvatures. Initial polyp candidates (IPCs) were then determined by thresholding the geometric measurements. Based on IPCs, several features were extracted for each IPC, and fed into a support vector machine to reduce false positives (FPs). The final detections were displayed in a commercial system to provide second opinions for radiologists. The CAD scheme was applied to 26 patient CTC studies with 32 confirmed polyps by both optical and virtual colonoscopies. Compared to our previous work, all the polyps can be detected successfully with less FPs. At the 100% by polyp sensitivity, the new method yielded 3.5 FPs/dataset. PMID:20428331

  2. 移动应用程序内存泄露机制分析与检测方案设计%Application code memory leak analysis and detecting technology research in mobile

    Institute of Scientific and Technical Information of China (English)

    朱洪军; 韩洋; 华保健; 陈灏

    2016-01-01

    Android development has become a hot field of mobile development, but memory usage problems in Android applications are often overlooked, part of the developers are lack of knowledge of Java garbage collection mechanism, which makes the memory leak become a very important issues in security area of Android application development. In this paper, the harm of memory leaks is expounded, it introduces some scenario of memory leak and sorts them according to the correlation of four components of Android, finally summarizes characteristics and puts forward a kind of memory leak code static code memory leak detection scheme based on symbolic execution.%Android开发已经成为移动开发热门领域,Android应用程序中内存使用的问题却经常容易被忽视,部分开发者对Java垃圾回收机制认识模糊,使得内存泄漏成为Android应用开发中十分隐秘但又确实存在的应用安全问题,对内存泄漏的危害进行了阐述,并根据与Activity、Service、ContentProvider、Broadcast Receiver等Android组件的相关性归类介绍了一些常见的典型内存泄漏情景,最后分析总结内存泄漏代码特征,并设计一种基于符号执行的内存泄漏静态代码检测方案。

  3. Dynamic modeling in compressible flow systems for application in real time leak detection; Modelagem dinamica em redes de escoamento compressivel para aplicacoes a deteccao de vazamentos em tempo real

    Energy Technology Data Exchange (ETDEWEB)

    Pires Neto, Joaquim Pamponet [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica. Lab. SDV - Dutos]. E-mail: joaquim@copene.com.br

    2002-06-01

    It is remarkable how there are hardly any computer tools that can build a transient behavioral analysis of process variables in a compressible flow, especially during starting and shutdown of plant. From this scenario, a modeling and dynamic simulation of compressible flow systems was built, and a computer method for detecting leaks in real time was presented. The phenomenon model is based on moment and continuity equations in transient basis. Unidimensional and isentropic natural gas flow was considered. The set of differential equations is solved through numerical integrations in time, using Runge-Kutta methods, after applying the finite elements method to spatial continuum. The suggested method for detection of leaks is based on the self-regressive stochastic parametric model. The procedure consist in generating process transient input and output data series, such as nodal pressures and flow rates in pipes, during the occurrence of the events programmed by the dynamic simulator and use them during training of IMO predictors in RX model structure, with constant update. The manifestation of a leak is detected by the instant deviation, statistically significant and beyond safety limits, between a group of predictions and the corresponding process measures. (author)

  4. 基于BP神经网络的盘管泄漏检测方法研究%Study of the coil-leak detective method based on the BP neural network

    Institute of Scientific and Technical Information of China (English)

    袁寅; 袁昌明; 王强

    2011-01-01

    The present paper is devoted to the study of the coil-leak detective method based on the BP neural network in hoping to extract its boundless application prospect. As a matter of fact, with the ever-increasing chemical safety demands, traditional offline pipe leak detection methods, such as pressure-keeping methods, which fail to meet the needs of on-line detection and control of the leakage of water coil of the reaction kettle for their poor real-time up-to-date performance. Flow balance method, though still effective in online leak-detection, also fails to meet the challenges of the fast-changing working conditions. Therefore, scientists began to face the challenge by using the flow balance method combined with neural network. In order to study the validity of this detection method, we have established an experimental platform of coil leak detection based on S7 - 300PLC. The platform can not only be able to simulate the leak of water coil, collect the flow data, but also produce warning alarms and help to control some sudden, unexpected leakage. Therefore, we have made an analysis of the flow changes in the inlet and outlet of the water coil of the reactor by means of a series of simulated experiments with the coil leakage, including the fast changing situations of working conditions and the leakage variations, we have also extracted characteristic signals (RMS) from the flow signal to protract RMS curve of flow. Careful comparison of the RMS curves of normal, leak and fast changing situations of working conditions, has offered us possibilities-to make clear the features of some quite different conditions. We have extracted RMS of the flow to construct the input matrix of the neural network. Through searching for a large number of experimental data to train the BP neural network, it becomes possible to work out the optimal neural network structures by comparing the network training error results of various structures. It is the BP neural network model we have

  5. Research on leak fault intelligent detection method for fluid pipeline based on fuzzy classification%基于模糊分类的流体管道泄漏故障智能检测方法研究

    Institute of Scientific and Technical Information of China (English)

    刘金海; 冯健

    2011-01-01

    本文针对基于负压波法管道泄漏实时检测系统误报高和灵敏度低的问题提出一种流体管道泄漏故障智能检测方法,该方法首先给出管道运行参数的确定模型,然后结合模糊算子给出流体管道状态模糊模型,进而利用该模型实现管道故障分类.以这种智能检测方法为核心设计流体管道故泄漏故障智能诊断系统(leak intelligent diagnosis system for fluid pipeline,LIDSFP),通过对某成品油管道实例仿真和在流体管道测试系统上的试验研究,给出了LIDSFP性能指标,进一步分析表明该系统可以有效完成流体管道的泄漏故障诊断.%A leak fault intelligent detection method for fluid pipeline based on fuzzy classifier is proposed, which can decrease false alarms and improve leak detection sensitivity. To complete real-time and exact fault diagnosis of fluid pipeline, a fuzzy classifier for operation states is designed according to the framework of fuzzy expert system. A leak fault intelligent diagnosis system for fluid pipeline ( LIDSFP) was designed with this intelligent method; simulation was carried out to detect faults from the historic operation data of certain petrolatum product fluid pipeline in China.Test study was also carried out on the proposed system and the performance specification of the system is given. Simulation and test results show that the proposed diagnosis system has good performance.

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

    Science.gov (United States)

    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.

  7. Scanning, standoff TDLAS leak imaging and quantification

    Science.gov (United States)

    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.

  8. VolHOG: a volumetric object recognition approach based on bivariate histograms of oriented gradients for vertebra detection in cervical spine MRI.

    Science.gov (United States)

    Daenzer, Stefan; Freitag, Stefan; von Sachsen, Sandra; Steinke, Hanno; Groll, Mathias; Meixensberger, Jürgen; Leimert, Mario

    2014-08-01

    The automatic recognition of vertebrae in volumetric images is an important step toward automatic spinal diagnosis and therapy support systems. There are many applications such as the detection of pathologies and segmentation which would benefit from automatic initialization by the detection of vertebrae. One possible application is the initialization of local vertebral segmentation methods, eliminating the need for manual initialization by a human operator. Automating the initialization process would optimize the clinical workflow. However, automatic vertebra recognition in magnetic resonance (MR) images is a challenging task due to noise in images, pathological deformations of the spine, and image contrast variations. This work presents a fully automatic algorithm for 3D cervical vertebra detection in MR images. We propose a machine learning method for cervical vertebra detection based on new features combined with a linear support vector machine for classification. An algorithm for bivariate gradient orientation histogram generation from three-dimensional raster image data is introduced which allows us to describe three-dimensional objects using the authors' proposed bivariate histograms. A detailed performance evaluation on 21 T2-weighted MR images of the cervical vertebral region is given. A single model for cervical vertebrae C3-C7 is generated and evaluated. The results show that the generic model performs equally well for each of the cervical vertebrae C3-C7. The algorithm's performance is also evaluated on images containing various levels of artificial noise. The results indicate that the proposed algorithm achieves good results despite the presence of severe image noise. The proposed detection method delivers accurate locations of cervical vertebrae in MR images which can be used in diagnosis and therapy. In order to achieve absolute comparability with the results of future work, the authors are following an open data approach by making the image dataset

  9. Sensitive hydrogen leak detector

    Science.gov (United States)

    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.

  10. Development and Characterization of Novel Volumetric Acquisition Orbits With an Application Specific Emission Tomograph for Improved Breast Cancer Detection

    Science.gov (United States)

    2005-08-01

    and P. Kuhn , "Scintimammography with R. J. Jaszczak, "Implementation and initial characterization of acquisi- dedicated breast camera detects and...NEMA Standards [45] J. Maublant, M. de Latour , D. Mestas, A. Clemenson, S. Charrier, Publication NU 1-2001. V. Feillel, G. Le Bouedec, P. Kaufmann, J

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Automated detection and volumetric segmentation of the spleen in CT scans; Automatische Detektion und volumetrische Segmentierung der Milz in CT-Untersuchungen

    Energy Technology Data Exchange (ETDEWEB)

    Hammon, M.; Dankerl, P.; Janka, R.; Uder, M.; Cavallaro, A. [Universitaetsklinikum Erlangen (Germany). Radiologisches Inst.; Kramer, M.; Seifert, S.; Tsymbal, A.; Costa, M.J. [Siemens AG, Erlangen (Germany). Corporate Technology

    2012-08-15

    To introduce automated detection and volumetric segmentation of the spleen in spiral CT scans with the THESEUS-MEDICO software. The consistency between automated volumetry (aV), estimated volume determination (eV) and manual volume segmentation (mV) was evaluated. Retrospective evaluation of the CAD system based on methods like ''marginal space learning'' and ''boosting algorithms''. 3 consecutive spiral CT scans (thoraco-abdominal; portal-venous contrast agent phase; 1 or 5 mm slice thickness) of 15 consecutive lymphoma patients were included. The eV: 30 cm{sup 3} + 0.58 (width x length x thickness of the spleen) and the mV as the reference standard were determined by an experienced radiologist. The aV could be performed in all CT scans within 15.2 ({+-} 2.4) seconds. The average splenic volume measured by aV was 268.21 {+-} 114.67 cm{sup 3} compared to 281.58 {+-} 130.21 cm{sup 3} in mV and 268.93 {+-} 104.60 cm{sup 3} in eV. The correlation coefficient was 0.99 (coefficient of determination (R{sup 2}) = 0.98) for aV and mV, 0.91 (R{sup 2} = 0.83) for mV and eV and 0.91 (R{sup 2} = 0.82) for aV and eV. There was an almost perfect correlation of the changes in splenic volume measured with the new aV and mV (0.92; R{sup 2} = 0.84), mV and eV (0.95; R{sup 2} = 0.91) and aV and eV (0.83; R{sup 2} = 0.69) between two time points. The automated detection and volumetric segmentation software rapidly provides an accurate measurement of the splenic volume in CT scans. Knowledge about splenic volume and its change between two examinations provides valuable clinical information without effort for the radiologist. (orig.)

  13. In-Space Distributed Fiber Optic Hydrogen Leak Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Broadband Photonics Inc. proposes development of a patent-pending distributed fiber optic sensor for in-space hydrogen leak detection. Reliable and fast detection of...

  14. In-Space Distributed Fiber Optic Hydrogen Leak Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Broadband Photonics Inc. proposes development of a patent-pending distributed fiber optic sensor for in-space hydrogen leak detection. Reliable and fast detection of...

  15. C/C ++program memory leak detection based on bounded model checking%基于有界模型检测的C/C++程序内存泄露检测

    Institute of Scientific and Technical Information of China (English)

    黄蔚; 洪玫; 杨秋辉; 郭鑫宇; 代声馨; 徐保平; 高婉玲; 赵鹤

    2016-01-01

    The dynamic memory management mechanism in C /C ++programming language is free and flexible,but when used by developer it is easy to introduce memory leaks which lead to performance degradation and even failure of system.In order to detect memory leak more effectively,this paper proposed a memory leak detection method based on bounded model checking for C program called MLD-CBMC.It took C /C ++program files as input,unwound the program and inserted memory leak proper-ties,encoded the program constraints and properties into verification conditions using satisfiability modulo theory,then passed the verification conditions to a SMT solver.Thus it converted detecting memory leaks to solving satisfiability problems.By ex-periment and cooperation with other bounded model checking tools,MLD-CBMC shows its feasibility and effectiveness.%C /C ++语言中的动态内存管理机制自由且灵活,但动态内存的使用容易引入内存泄露,导致系统性能降低甚至系统崩溃。为了更加有效地检测内存泄露,提出了一个基于有界模型检测技术的 C /C ++程序内存泄露检测方案 MLD-CBMC。该方案以 C /C ++程序文件为输入,利用有界模型检测技术对程序进行展开处理,加入内存泄露性质,并利用可满足性模理论(SMT)对程序约束和性质组成的验证条件编码,使用 SMT 求解器对验证条件求解,将检测内存泄露问题转换为求解可满足性问题,实现 C /C ++程序内存泄露的检测。通过实验验证了方案的有效性,并与其他有界模型检测工具进行对比实验,实验证明方案对内存泄露的检测能力更强。

  16. Development of a water leak detection system for LMFBR steam generator. Pt. 3. Experimental results for detection of bubbles using the SG sector model

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, Hiromichi; Yoshida, Kazuo [Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan). Komae Research Lab.

    1995-05-01

    In order to prevent the expansion of tube damages and to maintain structural safety in steam generators (SG) of liquid metal fast breeder reactor (LMFBR), it is necessary to detect precisely and immediately the leakage of water from tubes of heat exchangers. The active acoustic detection method, which detects the sound attenuation due to bubbles generated at the sodium-water reactions, has drawn general interests owing to its short response time and reduction of the influence of background noise. Sound attenuation is also subjected to structures such as heat transfer tubes and shrouds. Accordingly, it is necessary to evaluate the sound attenuation due to structures. However, studies in these respects are very few. In this paper, using the water bath and SG sector model, the attenuation characteristics of sounds due to flat plates and heat transfer tubes are investigated under various conditions and discussed. (author).

  17. Operational Philosophy Concerning Manned Spacecraft Cabin Leaks

    Science.gov (United States)

    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

  18. Remote leak localization approach for fusion machines

    Energy Technology Data Exchange (ETDEWEB)

    Durocher, Au., E-mail: aurelien.durocher@cea.fr [CEA-IRFM, F-13108 Saint Paul-Lez-Durance (France); Bruno, V.; Chantant, M.; Gargiulo, L. [CEA-IRFM, F-13108 Saint Paul-Lez-Durance (France); Gherman, T. [Floralis UJF Filiale, F-38610 Gières (France); Hatchressian, J.-C.; Houry, M.; Le, R.; Mouyon, D. [CEA-IRFM, F-13108 Saint Paul-Lez-Durance (France)

    2013-10-15

    120 °C), “ppm” traces of helium or water have been measured. To improve these first promising results, a new test-bed called ROVE (remote operation vacuum equipment) has been set up in 2012 to qualify leak sensors and remote operation. A list of concepts has been set out from contacts with manufacturers and laboratories. For sniffing solutions it includes laser absorption measurement, mass spectrometer analyses and vibrating quartz. For embeddable concepts thermal conductivity and capacitive sensors are considered. Choice of concepts to detect water or helium traces is based on major criteria, such as weight, high sensibility and fast response time and recovery time. They also have to be operational under primary vacuum conditions or atmospheric pressure and from ambient temperature to 60 °C.

  19. Active acoustic leak detection for LMFBR steam generators. Pt. 4. Experimental results for detection of bubble using the SG full sector model

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, Hiromichi [Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan). Komae Research Lab.

    1996-06-01

    In order to prevent the expansion of tube damages and to maintain structural safety in steam generators (SG) of fast breeder reactor (FBR), it is necessary to detect precisely and immediately the leakage of water from tubes of heat exchangers. The active acoustic method, which detects the sound attenuation due to bubbles generated at the sodium-water reactions, is being developed. In this paper, the attenuation characteristics of sound attenuated by bubbles are investigated experimentally by using the SG full sector model simulating the actual SG. An emitter and a receiver sensor are attached to the SG shell, and the attenuation of sounds due to passing of bubbles through the sound field is detected and measured. As a experimental result, it is clarified that the received sound attenuates immediately upon injection of bubbles, and the attenuation of sound are 2-5 dB at after 10 seconds from bubble injection of 10 l/s. The attenuation of sound are least affected by bubble injection location. (author)

  20. MRI and 1H-MRS detects volumetric and metabolic abnormalities of hippocampal sclerosis in temporal lobe epilepsy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective:To further investigate the ability of MRI and 1H-MRS techniques for presurgical evaluation of hippocampal sclerosis. Methods:MRI and 1H-MRS were performed on 30 healthy subjects to determine the confidence levels. Eight patients who were pathologically confirmed hippocampal sclerosis were then studied using the same protocols. The difference of hippocampal formation (DHF) was used to determine atrophy of hippocampus. Areas under the peak of N-acetylaspartate(NAA) ,Creatine(Cr) and Choline (Cho) were measured, and the ratios of NAA/Cr, Cho/Cr, and NAA/Cr+Cho were calculated. NAA/Cr+Cho value was applied to localize the seizure focus. Results:Two patients showed hippocampal atrophy according to DHF value. NAA/Cr ratio decreased significantly in ipsilateral hippocampus compared to that in contralateral hippocampus and control subjects(P<0.01). Cho/Cr value increased in both ipsi-and contralateral hippocampus in comparison with that in control subjects(P<0.01). NAA/Cr+Cho ratio, however, significantly reduced in both ipsi-and contralateral hippocampus(P<0.01) with lowest NAA/Cr+Cho ratio in seizure foci. Six patients could be lateralized by reduced and/or asymmetric NAA/Cr+Cho value. Conclusion:1H-MRS should be a promising diagnostic tool to detect neuron abnormality.1H-MRS and MRI complement each other hi presurgical lateralization of epileptogenic lesion in epilepsy patients.

  1. MR assessment of lumbar disk herniation treated with oxygen-ozone diskolysis: the role of DWI and related ADC versus intervertebral disk volumetric analysis for detecting treatment response.

    Science.gov (United States)

    Splendiani, A; Perri, M; Conchiglia, A; Fasano, F; Di Egidio, G; Masciocchi, C; Gallucci, M

    2013-06-01

    We prospectively assessed the diagnostic criteria of morphologic MRI study (MMS) and the accuracy of DWI and related ADC values (DWI-ADC) versus intervertebral disk volumetric analysis (IDVA) for predicting shrinkage of lumbar disk herniation treated with oxygen-ozone (O2-O3) diskolysis. Sixty-eight patients (36 men and 32 women; mean age 39) with lumbosciatica underwent O2-O3 diskolysis. The six-month MRI follow-up was performed with FSE-T2 and T2-fat, SE-T1 and DWI-weighted images. IDVA was determined using OsiriX(®). Diagnostic criteria and accuracy were evaluated with regards to DWI and related ADC in detecting response to ozone therapy. Fifty-eight of 68 patients had successful outcomes (responders), whereas ten patients showed unsatisfactory outcomes (non-responders). MMS showed that a centrally located herniated disk and grade 1 nerve root compression were more common in the responder group (p < 0.05). DWI-ADC and IDVA showed statistically significant shrinkage in the sixth month of follow-up (p < 0.05) with a mean ADC value reduction of 2.10 × 10(-3) mm(2)/s +/- 0.19 SD in the second month of follow-up (p < 0.05). DWI-ADC had an accuracy of 0.81 in detecting response to therapy around the second month of follow-up. DWI-ADC appear to be useful adjuncts to MMS in the follow-up of patients undergoing O2-O3 diskolysis.

  2. 基于时延的高精度泄漏点超声定向检测方法%High accuracy method of ultrasonic gas leak direction detection based on time delay estimation

    Institute of Scientific and Technical Information of China (English)

    廖平平; 蔡茂林

    2013-01-01

    In order to solve the low accuracy problem in current gas leak detection, a new ultrasonic leak detection method based on time delay estimation (TDE) was proposed. Three ultrasonic sensors arranged in an equilateral triangle and received the ultrasound generated by a gas leak and the leak direction can be determined according to time delays between the outputs of every two sensors. A TDE algorithm based on cubic spline interpolation was adopted to overcome the accuracy limit caused by sampling interval. For each kernel window length, delay estimates of 100 sets of experimental data were obtained and their mean squared errors (MSE) were calculated. Comparison between MSE of experimental data and Cramer-Rao lower bound showed that their changing tendency was accordant. Influences of MSE, the space between sensors and the distance between leak and sensor on direction accuracy were analyzed. Results show that the direction error increases with MSE, decreases with the space between sensors, and increases with distance between leak and sensor. The direction detection accuracy is improved by 7 ~10 times compared with detection method with single ultrasonic sensor.%针对当前气体泄漏点检测定向精度低的情况,提出一种基于时延的高精度超声检测方法.该方法利用3个呈等边三角形分布的超声传感器接收由泄漏点产生的超声波,根据3路信号的相对时延值确定泄漏点的方向.为克服采样间隔对时延估计精度的限制,采用基于三次样条插值的时延估计算法估计信号时延值,并对不同核窗长度下的各100组实验数据的时延值进行误差统计,得到其均方差并与其Cramér-Rao下界比较,发现二者的变化趋势具有良好的一致性.在此基础上研究了时延值均方差,超声传感器间距和泄漏点距离对定向精度的影响.结果表明:定向误差随时延值均方差增大而增大,随超声传感器间距增大而减小,随泄漏点距离增大而增大

  3. 105 K-West isolation barrier leak recovery plan

    Energy Technology Data Exchange (ETDEWEB)

    Wiborg, J.C.

    1995-03-02

    Leak testing is being performed in 105 KW to verify the performance of the isolation barriers which have been recently installed. When an 11 inch differential head is established between the main basin and the discharge chute, a leak-rate of approximately 30 - 35 gpm is observed. The leak-rate would be achieved by a 1.65`` - 2`` diameter hole (or equivalent). Analyses suggest that the flow is turbulent/laminar transitional (dominantly turbulent), which would be indicative of a single point leak, typical of a pipe or large opening. However, local vortex rotation is observed in the entry to the West transfer chute while no observable motion was seen in the East transfer chute: this may be an indication of seal leakage in the East isolation barrier. The potential for leakage had been considered during the design and field work planning stages. Review of potential leak detection technologies had been made; at the planning stage it was determined that location specific leak detection could be established relatively quickly, applying existing K Basins technology (dye or ultrasonics). The decision was made not to pre-stage leak detection since the equipment development is highly dependent on the nature and location of the leak, and the characteristics of the leak rate provides data which guides leak characterization technology. The expense could be deferred and potentially avoided without risk to critical path activity. Consistent with the above, a systematic recovery plan has been developed utilizing phased activities to provide for management discipline combined with timely diagnosis and correction. Because this activity is not critical path at this time, activities will be coordinated with other plant activity to optimize overall plant work. Particular care will be exercised in assuring that information gained from this recovery can be utilized in the more critical work in 105 KE.

  4. Summary of QRL 7-8 Repair and Re-installation Leak Test Results

    CERN Document Server

    Kos, N; CERN. Geneva. TE Department

    2009-01-01

    This note describes the leak tests that have been performed during the repair and re-installation of QRL sector 7-8 during 2005 and 2006. The leak tests were performed in UX65, where the pipe elements were refurbished before re-installation, and in the tunnel. A variety of leaks have been detected, localised and repaired in the tunnel, including weld defects, accidentally drilled holes and imported leaks in previously tested components.

  5. MASS SPECTROMETER LEAK

    Science.gov (United States)

    Shields, W.R.

    1960-10-18

    An improved valve is described for precisely regulating the flow of a sample fluid to be analyzed, such as in a mass spectrometer, where a gas sample is allowed to "leak" into an evacuated region at a very low, controlled rate. The flow regulating valve controls minute flow of gases by allowing the gas to diffuse between two mating surfaces. The structure of the valve is such as to prevent the corrosive feed gas from contacting the bellows which is employed in the operation of the valve, thus preventing deterioration of the bellows.

  6. 半导体真空腔体静态密封和检漏的研究%Static Sealing and Leak Detection of Semiconductor Vacuum Chamber

    Institute of Scientific and Technical Information of China (English)

    陈妙娟

    2016-01-01

    针对半导体真空腔体静态密封中存在的泄漏及高温时密封圈受损等密封性问题,重新对密封圈的选择和密封槽的设计计算进行了完善,并对完善后的真空腔体的密封性进行了一系列的检漏测试及探讨,从而证明了改善方案的可行性。%This article focused on solving the problems of static sealing which caused the air leak and the O-ring damaging at high temperature in semiconductor vacuum chamber by choosing the O-ring and improving the sealing groove .Through further studying and a series of air leak test of the improved vacuum chamber ,it is proved that the improved solution is feasible .

  7. Development Actualities of Pipeline Leak-detection Technologies at Home and Abroad%国内外油气管道泄漏检测技术的发展现状

    Institute of Scientific and Technical Information of China (English)

    夏海波; 张来斌; 王朝辉

    2001-01-01

    介绍了国内外用于油气管道泄漏的十几种检测方法,包括气体检测法、压力分布法、负压波检测法、质量平衡法、检测元件法、声波法、分段试压法、压力点分析法、压力波阵面检测法以及示踪剂检测法等。分析了各种管道泄漏检测技术的原理和各方法的优缺点。认为在现代计算机技术的支持下,那些基于快速算法的实时管道泄漏检测技术将显示其优越性。%In this paper,some oil and gas pipeline leak-detectiontechnologies at home and abroad are introduced,including gas detection method,pressure distribution method,negative pressure wave detection method,testing element method,acoustic wave method,parts testing pressure method,pressure point analysis,pressure wave front detection,tracer detection methods,radioactivity detection and pipeline instantaneous model method.The advantages and weaknesses of all detection methods are analyzed.The authors considers that in the support of modern computer technology,those real-time pipeline leak detection technologies on the basis of fast algorithm will demonstrate their advantages.

  8. Uncertainty evaluation of vacuum chamber leak detection method for spacecraft component%航天器单机产品真空室检漏法测量结果的不确定度评定

    Institute of Scientific and Technical Information of China (English)

    汪力; 王勇; 孙立臣; 孙立志; 张海峰; 史纪军; 郭海涛

    2012-01-01

    航天器推进系统的单机产品的漏率测试往往采用氦质谱真空室检漏法,研究该方法测量结果的不确定度评定具有重要的工程应用价值.本文首先对真空室检漏法的原理进行了分析探讨,并从不确定的基础理论出发系统地研究了氦质谱真空室检漏法测量结果的不确定度评定方法,并结合工作的具体案例给出了评价的具体步骤.%Vacuum chamber leak detection method is widely used in (he spacecraft components of propellent subsystem. So it is very important to study the uncertainty evaluation of this method. First, the principle of the vacuum chamber leak detection method was analyzed. Second, the method of uncertainty evaluation was studied based on the basic theory about uncertainty. Last, the detailed evaluation steps were given through a case.

  9. A report on the leak before break design and evaluation of LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Bum; Lee, H. Y.; Joo, Y. S.; Lee, J. H. [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-05-01

    In this study, the necessity of leak before break application for Liquid Metal Reactors (LMR) was investigated and the outline of leak before break evaluation procedure for KALIMER reactor structures and components was proposed. In the 1st phase of this project, the theoretical background for leak before break procedure was prepared based upon the state-of-the-art technology of the advanced countries. In the 2nd phase of project, evaluation method of creep crack growth was studied and the leak before break evaluation procedure of French RCC-MRA -16 was analyzed. Also, creep-fatigue crack growth was assessed according to the Japanese JNC method and this will help to establish the KALIMER leak before break procedure. It is necessary to specify proposed KALIMER leak before break evaluation technique including high temperature crack growth evaluation, stability analysis of crack growth, leak rate evaluation method, and leak detection technology. 24 refs., 12 figs., 4 tabs. (Author)

  10. 40 CFR 63.1005 - Leak repair.

    Science.gov (United States)

    2010-07-01

    ... successful repair of the leak. (3) Maximum instrument reading measured by Method 21 of 40 CFR part 60... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Leak repair. 63.1005 Section 63.1005... Standards for Equipment Leaks-Control Level 1 § 63.1005 Leak repair. (a) Leak repair schedule. The owner...

  11. Research project RoboGas{sup Inspector}. Gas leak detection with autonomous mobile robots; Forschungsprojekt RoboGas{sup Inspector}. Gaslecksuche mit autonomen mobilen Robotern

    Energy Technology Data Exchange (ETDEWEB)

    Habib, Abdelkarim [BAM Bundesanstalt fuer Materialforschung und -pruefung, Berlin (Germany); Bonow, Gero; Kroll, Andreas [Fachgebiet Mess- und Regelungstechnik, Universitaet Kassel, Kassel (Germany); Hegenberg, Jens; Schmidt, Ludger [Fachgebiet Mensch-Maschine-Systemtechnik, Universitaet Kassel, Kassel (Germany); Barz, Thomas; Schulz, Dirk [Fraunhofer FKIE, Unbemannte Systeme, Wachtberg (Germany)

    2013-05-15

    As part of the promotional program AUTONOMIK of the Federal Ministry of Economics and Technology (Berlin, Federal Republic of Germany) a consortium of nine project partners developed a prototype of an autonomous mobile robot looking for gas leaks in extended industrial equipment. The autonomous mobility of the system for any systems was implemented using different types of sensors for self-localization and navigation. The tele-operation enables a manual intervention in the process. The robot performs inspection tasks in industrial plants by means of video technology and remote gas measurement technology without driving into the possible risk areas and without the presence of humans. The robot can be used for routine inspections of facilities or for the targeted inspection of specific plant components. Thanks to the remote sensing technique also plant components can be inspected which are difficult to be inspected due to their limited accessibility by conventional measurement techniques.

  12. Using hyperspectral plant signatures for CO2 leak detection during the 2008 ZERT CO2 sequestration field experiment in Bozeman, Montana

    Energy Technology Data Exchange (ETDEWEB)

    Male, E.J.; Pickles, W.L.; Silver, E.A.; Hoffmann, G.D.; Lewicki, J.; Apple, M.; Repasky, K.; Burton, E.A.

    2009-11-01

    Hyperspectral plant signatures can be used as a short-term, as well as long-term (100-yr timescale) monitoring technique to verify that CO2 sequestration fields have not been compromised. An influx of CO2 gas into the soil can stress vegetation, which causes changes in the visible to nearinfrared reflectance spectral signature of the vegetation. For 29 days, beginning on July 9th, 2008, pure carbon dioxide gas was released through a 100-meter long horizontal injection well, at a flow rate of 300 kg/day. Spectral signatures were recorded almost daily from an unmown patch of plants over the injection with a ''FieldSpec Pro'' spectrometer by Analytical Spectral Devices, Inc. Measurements were taken both inside and outside of the CO2 leak zone to normalize observations for other environmental factors affecting the plants.

  13. 分布式光纤油气长输管道泄漏检测及预警技术%Distributed fiber oil and gas pipeline leak detection and warning technology

    Institute of Scientific and Technical Information of China (English)

    张富斌

    2015-01-01

    管道用于油气运输有着独特的优势,因此成为了运输油气的主要手段。在实际油气的运输过程中因为人为因素和自然因素等原因,经常会导致运输油气的管道发生泄漏事故,这不仅造成环境污染,而且会威胁到人们的生命财产安全。本文介绍了分布式光纤油气长输管道泄漏检测及预警技术在油田的应用。%For oil and gas transportation pipeline has a unique advantage, it became the primary means of transportation of oil and gas. In the actual transportation of oil and gas, man-made and natural factors and other reasons often resulted the transport of oil and gas pipeline leak accident, which not only affected environmental pollution, but also threatened people’s life and property safety.This article introduced distributed fiber oil and gas pipeline leak detection and warning technology.

  14. The Demonstration of a Robotic External Leak Locator on the International Space Station

    Science.gov (United States)

    Naids, Adam; Rossetti, Dino; Bond, Tim; Johnson, Brien; Huang, Alvin; Deal, Alexandra; Fox, Katie; Heiser, Michael; Hartman, William; Mikatarian, Ronald

    2017-01-01

    The International Space Station (ISS) and all currently conceivable future manned spacecraft are susceptible to mission impacts due to fluid/gas leaks to the exterior environment. For example, there is a well-known risk of ammonia leaks from the ISS External Thermal Control System loops and currently no method to locate them. It was, therefore, critical to develop a method for detecting and locating leaks to preserve vehicle health. The Robotic External Leak Locator (RELL) was developed and deployed to the ISS to provide this capability. An on-orbit validation and demonstration was successfully completed in December 2016 and leak locating operations occurred in February 2017. This paper discusses the results of those exercises including measurements of the environment around ISS, detection of the small ammonia leak and implementation of leak locating methodologies.

  15. 基于太阳能充电的无线远程监控氯气泄漏系统%Wireless Remote Monitor System of Detecting the Leaking of Chlorine Gas Based on Solar Energy Charging

    Institute of Scientific and Technical Information of China (English)

    王金辉; 周巧娣; 徐勤利; 蒋科学; 陈文华

    2013-01-01

    根据工业用氯气的量大以及罐体存储的需求,选用基于GSM的远程监控系统对氯气泄漏进行检测.用太阳能电池板实现白天对系统供电以及对锂电池充电,夜晚完全由锂电池对供电.系统微控制器选用MSP430,以达到超低功耗的功能.对于氯气泄漏的信号采集使用CL2-A1电化学式氯气传感器,实现到对泄漏氯气快速检测做出反应的效果.该设计具有适用范围广,通用性强,能现场以及远程报警等优点.%Based on the large amount of chlorine for industrial use and storage of tank requirements, GSM-based remote monitoring system is selected to detect chlorine leaks. During the day the system uses solar panels as the system power supply and battery charger, but lithium-powered by night. In order to achieve ultra-low power consumption features, system uses ultra-low power microcontroller's MSP430. For acquisition of chlorine leakage signal, CL2 - Al Electrochemical chlorine sensor is used in the design, in order to achieve a rapid detection of chlorine leak response effect. The design has advantages of wide range of application, versatility, and can site and remote alarm.

  16. 生物安全实验室效率检漏型高效空气过滤装置的研制%Development of HEPA Filter Unit with Efficiency Leak Detection for Bio-safety Laboratory

    Institute of Scientific and Technical Information of China (English)

    张宗兴; 赵明; 衣颖; 祁建城

    2013-01-01

    目的:研制一种可安装在生物安全实验室内的效率检漏型排风高效过滤装置,可实现对高效空气过滤器的原位检漏和消毒.方法:依据高效空气过滤器效率法检测和气体消毒要求,进行高效空气过滤装置的结构设计.结果:该高效空气过滤装置,可采用效率法对高效过滤器进行原位检漏,并可对过滤器进行原位气体消毒及验证消毒效果,满足相关标准要求.结论:该装置适用于生物安全实验室的污染空气排放处置,可满足我国生物安全实验室建设的需要.%Objective To develop an exhaust HEPA filter unit installed in the laboratory that has the functions of in-situ leak detection and sterilization of HEPA filter.Methods The structure composition of the unit was designed according to the requirement of efficiency test and gas sterilization of HEPA filter.Results The HEPA filter unit which met relevant standard requirements had the functions of in-situ leak detection using efficiency test,sterilization and validating the effect of sterilization of HEPA filter.Conclusion The unit which is applicable to decontamination of contaminated air emissions of bio-safety laboratory can meet the needs of construction of bio-safety laboratory in China.

  17. FUZZY INFERENCE BASED LEAK ESTIMATION IN WATER PIPELINES SYSTEM

    Directory of Open Access Journals (Sweden)

    N. Lavanya

    2015-01-01

    Full Text Available Pipeline networks are the most widely used mode for transporting fluids and gases around the world. Leakage in this pipeline causes harmful effects when the flowing fluid/gas is hazardous. Hence the detection of leak becomes essential to avoid/minimize such undesirable effects. This paper presents the leak detection by spectral analysis methods in a laboratory pipeline system. Transient in the pressure signal in the pipeline is created by opening and closing the exit valve. These pressure variations are captured and power spectrum is obtained by using Fast Fourier Transform (FFT method and Filter Diagonalization Method (FDM. The leaks at various positions are simulated and located using these methods and the results are compared. In order to determine the quantity of leak a 2 × 1 fuzzy inference system is created using the upstream and downstream pressure as input and the leak size as the output. Thus a complete leak detection, localization and quantification are done by using only the pressure variations in the pipeline.

  18. Estimation of leak rate through circumferential cracks in pipes in nuclear power plants

    Directory of Open Access Journals (Sweden)

    Jai Hak Park

    2015-04-01

    Full Text Available The leak before break (LBB concept is widely used in designing pipe lines in nuclear power plants. According to the concept, the amount of leaking liquid from a pipe should be more than the minimum detectable leak rate of a leak detection system before catastrophic failure occurs. Therefore, accurate estimation of the leak rate is important to evaluate the validity of the LBB concept in pipe line design. In this paper, a program was developed to estimate the leak rate through circumferential cracks in pipes in nuclear power plants using the Henry–Fauske flow model and modified Henry–Fauske flow model. By using the developed program, the leak rate was calculated for a circumferential crack in a sample pipe, and the effect of the flow model on the leak rate was examined. Treating the crack morphology parameters as random variables, the statistical behavior of the leak rate was also examined. As a result, it was found that the crack morphology parameters have a strong effect on the leak rate and the statistical behavior of the leak rate can be simulated using normally distributed crack morphology parameters.

  19. In-service helium leak testing of vacuum furnace

    Science.gov (United States)

    Ahmad, Anis; Tripathi, S. K.; Sawant, P. S.; Mukharjee, D.; Shah, B. K.

    2012-11-01

    Helium leak detection of vacuum furnaces and equipments used for processing of nuclear material is generally carried out by utilizing vacuum spray technique. In this technique helium leak detector is connected to the furnace, back ground reading is noted and helium gas is sprayed on all the suspected joints. Any increase in back ground is noted as leak signal. Processing of Zirconium alloy cladded fuel pins is carried out in vacuum furnace of about 3 meter length and 500 mm inside diameter. Furnace is connected with two numbers of rotary vacuum pump and one number of diffusion pump for creating vacuum (1 × 10-6 torr) inside the furnace. It is desirable that furnace should have good vacuum and best possible leak tightness during dynamic and static vacuum. During dynamic vacuum at higher temperature although required vacuum is achieved the furnace may have fine leakage through which air may enter and cause oxidation of clad tube leading to change in its coloration. This change in coloration will cause rejection of fuel element. Such fine leakages may not be reflected in the dynamic vacuum of the system at high temperature. During trial run change in coloration of outside surface of clad tube was observed although dynamic vacuum of the furnace was in the range of 1×10-6 torr range. To eliminate such possibilities of oxidation due to fine leakages in the system, it was decided to carry out in-service leak testing of the furnace. Helium leak testing of the furnace was carried out by using vacuum spray method and leaks observed were repaired and furnace was retested to ensure the leak tightness. The in-service helium leak testing of the furnace helped in maintaining its leak tightness during service under dynamic vacuum and prevent oxidation of fuel element. This paper describes the techniques of in- service helium leak testing, it's importance for detection of fine leak under dynamic vacuum and discusses details of the testing method and result obtained.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Myneni, Ganapati Rao

    1997-01-01

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

  2. Volumetric composition of nanocomposites

    DEFF Research Database (Denmark)

    Madsen, Bo; Lilholt, Hans; Mannila, Juha

    2015-01-01

    Detailed characterisation of the properties of composite materials with nanoscale fibres is central for the further progress in optimization of their manufacturing and properties. In the present study, a methodology for the determination and analysis of the volumetric composition of nanocomposites...... is presented, using cellulose/epoxy and aluminosilicate/polylactate nanocomposites as case materials. The buoyancy method is used for the accurate measurements of materials density. The accuracy of the method is determined to be high, allowing the measured nanocomposite densities to be reported with 5...... significant figures. The plotting of the measured nanocomposite density as a function of the nanofibre weight content is shown to be a first good approach of assessing the porosity content of the materials. The known gravimetric composition of the nanocomposites is converted into a volumetric composition...

  3. Natural gas pipeline leaks across Washington, DC.

    Science.gov (United States)

    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.

  4. 基于混沌理论的城市供水系统漏损检测新方法%A New Method to Leak Detection in Water System Based on Chaos Theory

    Institute of Scientific and Technical Information of China (English)

    张琴; 朱庆建; 汪雄海

    2013-01-01

    Considering the importance of leak detection to energy efficiency in urban water system,a new method to leak detection based on chaos theory is presented.The chaotic evolutional characters of successive users were used to detect pipe break or the leakage.By extracting the correlation dimension、Lyapunov exponent、attractor phase diagram and R/S analysis of hourly water consumption,the water time series of successive users were proved to be fractal and chaotic chaining relevant.On the basis,the different chaotic characters of booster and leakage were compared by phase diagram and the maximum Lyapunov exponent variation.Test results show that the chaotic characters are changed immediately when the booster occurs,and slow leakage can be discovered after two hours.Thus this method supplies new judgments to effectively amend water system in time and decrease the loss of water resource.%针对漏损检测对城市供水系统节能降耗的重要性,研究时用水量的混沌特性并提出一种基于混沌理论的漏损检测新方法,利用沿程用户时用水量的混沌演化特性来检测漏损故障和漏水.根据城市时用水量的时间序列,提取关联维数、最大Lyapunov指数、吸引子相图和R/S等混沌特征指数,分析沿程城市用水量观测序列的分形和链级混沌关联,并在此基础上,依据系统相图和最大Lyapunov指数变化来比较漏损故障和漏水时序的不同混沌特性.仿真结果表明,漏损故障时的混沌特性显著改变并能立即检测到,缓慢漏水2h后混沌特性变化明显,为及时修补供水系统提供依据,减小了资源损耗.

  5. Flexible Volumetric Structure

    Science.gov (United States)

    Cagle, Christopher M. (Inventor); Schlecht, Robin W. (Inventor)

    2014-01-01

    A flexible volumetric structure has a first spring that defines a three-dimensional volume and includes a serpentine structure elongatable and compressible along a length thereof. A second spring is coupled to at least one outboard edge region of the first spring. The second spring is a sheet-like structure capable of elongation along an in-plane dimension thereof. The second spring is oriented such that its in-plane dimension is aligned with the length of the first spring's serpentine structure.

  6. Influence of Crack Morphology on Leak Before Break Margins

    Energy Technology Data Exchange (ETDEWEB)

    Weilin Zang (Inspecta Technology AB, Stockholm (SE))

    2007-11-15

    The purpose of the project is to evaluate the deterministic LBB-margins for different pipe systems in a Swedish PWR-plant and using different crack morphology parameters. Results: - The influence of crack morphology on Leak Before Break (LBB) margins is studied. The subject of the report is a number of LBB-submittals to SKI where deterministic LBB-margins are reported. These submittals typically uses a surface roughness of 0.0762 mm (300 microinch) and number of turns equal to zero and an in-house code for the leak rate evaluations. The present report has shown that these conditions give the largest LBB-margins both in terms of the quotient between the critical crack length and the leakage crack size and for the leak rate margin. - Crack morphology parameters have a strong influence on the leak rate evaluations. Using the SQUIRT code and more recent recommendations for crack morphology parameters, it is shown that in many cases the evaluated margins, using 1 gpm as the reference leak rate detection limit, are below the safety factor of 2 on crack size and 10 on leak rate, which is generally required for LBB approval. - The effect of including weld residual stresses on the LBB margins is also investigated. It is shown that for the two examples studied, weld residual stresses were important for the small diameter thin wall pipe whereas it was negligible for the large diameter thick wall pipe which had a self-balanced weld residual stress distribution

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

    Science.gov (United States)

    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.

  8. 基于局部堆内存抽象表示的堆操作程序内存泄露检测%Memory Leak Detection for Heap-Manipulating Programs Based on Local Heap Abstraction

    Institute of Scientific and Technical Information of China (English)

    董龙明; 王戟; 陈立前; 董威

    2012-01-01

    There are many operations about shared and mutable data structures in heap-manipulating programs, such as allocation, combination, separation, deletion, and so on. Therefore, memory leak detection for these programs requires precise field-sensitive pointer alias information, which becomes more complex and harder to deal with. A novel field-sensitive heap abstraction approach based on extended pointer types is proposed for heap-manipulating programs in this paper. The approach computes the local layout around pointer variables in the heap, and therefore supports local reasoning for heap. The pointer alias sets are computed about the memory cells, which are reached by the pointer along various pointer fields in the given abstract distance domain. Various operation semantics about all basic statements based on extended pointer types are defined and a new algorithm runs typical forward dataflow iteration analysis to see whether there are any memory leaks. Our algorithm also supports both intra- and inter- procedural analysis. We have implemented the prototype tool (Heapcheck) for C programs in the Crystal open compiler framework to support detecting memory leaks about different pointer fields in complex data structures. Experimental evaluation about a set of C benchmark programs shows that the proposed approach has better scalability and precision than current work.%堆操作程序通过共享易变数据结构可灵活地申请、合并、删除堆内存.这类程序的内存泄漏检测要求精确的域敏感的指针别名信息,变得尤其复杂和难以处理.针对这个问题,提出了基于“指针扩展类型”域敏感的堆内存抽象方法,对指针变量在形态上的排列关系进行抽象以支持堆的局部推理.首先,定义了各种基本语句的操作语义,然后基于该抽象方法采用前向数据流迭代算法提出了一种新的内存泄露检测算法.在Crystal编译框架下实现了面向C程序的内存泄漏检测原型工

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

    Science.gov (United States)

    Sasaki, Y. Tito; Bergquist, Lyle E.

    1990-09-01

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

  10. Study of Internal and External Leaks in Tests of Anode-Supported SOFCs

    DEFF Research Database (Denmark)

    Rasmussen, Jens Foldager Bregnballe; Hendriksen, Peter Vang; Hagen, Anke

    2008-01-01

    A planar anode-supported solid oxide fuel cell (SOFC) has been tested to investigate gas tightness of the electrolyte and the applied seals. Gas leaks reduce the efficiency of the SOFC and it is thus important to determine and minimise them. Probe gases (He and Ar) and a Quadrupole Mass Spectrome......A planar anode-supported solid oxide fuel cell (SOFC) has been tested to investigate gas tightness of the electrolyte and the applied seals. Gas leaks reduce the efficiency of the SOFC and it is thus important to determine and minimise them. Probe gases (He and Ar) and a Quadrupole Mass...... Spectrometer were used to detect both internal (through electrolyte) and external (through seals) gas leaks. The internal gas leak through the electrolyte was quantified under different conditions, as was the external leak from the surroundings to the anode. The internal gas leak did not depend on the pressure...... and pressure gradients. The measured gas leaks deduced from the probe gas experiments and the total leak calculated from the deviation between the Emf defined by the gases and the cell OCV (which contains all gas leaks as well as effects of electronic leaks) were compared. Good agreement between the two...

  11. Novel Fiber Optic Sensor Probe with a Pair of Highly Reflected Connectors and a Vessel of Water Absorption Material for Water Leak Detection

    Directory of Open Access Journals (Sweden)

    Tae-Sik Cho

    2012-08-01

    Full Text Available The use of a fiber optic quasi-distributed sensing technique for detecting the location and severity of water leakage is suggested. A novel fiber optic sensor probe is devised with a vessel of water absorption material called as water combination soil (WCS located between two highly reflected connectors: one is a reference connector and the other is a sensing connector. In this study, the sensing output is calculated from the reflected light signals of the two connectors. The first reflected light signal is a reference and the second is a sensing signal which is attenuated by the optical fiber bending loss due to the WCS expansion absorbing water. Also, the bending loss of each sensor probe is determined by referring to the total number of sensor probes and the total power budget of an entire system. We have investigated several probe characteristics to show the design feasibility of the novel fiber sensor probe. The effects of vessel sizes of the probes on the water detection sensitivity are studied. The largest vessel probe provides the highest sensitivity of 0.267 dB/mL, while the smallest shows relatively low sensitivity of 0.067 dB/mL, and unstable response. The sensor probe with a high output value provides a high sensitivity with various detection levels while the number of total installable sensor probes decreases.

  12. LOCATING LEAKS WITH ACOUSTIC TECHNOLOGY

    Science.gov (United States)

    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. Variable gas leak rate valve

    Energy Technology Data Exchange (ETDEWEB)

    Eernisse, Errol P. (Albuquerque, NM); Peterson, Gary D. (Albuquerque, NM)

    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.

  14. The Design of Intelligent System for Gas Leak Detection in Substation%变电站气体泄漏检测的智能系统设计

    Institute of Scientific and Technical Information of China (English)

    苏镇西; 马凤翔; 吴雪莲

    2016-01-01

    针对传统变电站气体泄漏检测工作中存在的工作效率低、安全性差且误差较大等问题,提出了一种基于磁导航和RFID定位、3G无线通信网络等技术的气体泄漏智能检测系统。该系统通过3G无线通信网络将变电站气体泄漏AGV巡检采集的现场数据信息,实时传输到后台管理系统和监控管理中心,便于监管人员动态掌握变电站设备气体泄漏情况和运行工况,从而科学制定安排维护工作,为设备气体泄漏检修和状态管理提供重要参考依据。%There are some defects in traditional substation gas leakage detection, such as low work efficiency, poor security and larger error. To overcome these shortcomings, an intelligent system of gas leakage detection is proposed and implemented based on magnetic navigation, RFID location and 3G wireless network. This system achieves the field information data collected by AGV, and delivered to the central server system through 3G wireless network. It can provide an important reference to build the scientifically gas leakage detection and maintenance management work.

  15. Anastomotic leaks after bariatric surgery: it is the host response that matters.

    Science.gov (United States)

    Al-Sabah, Salman; Ladouceur, Martin; Christou, Nicolas

    2008-01-01

    Anastomotic leaks after bariatric surgery can lead to severe complications and adverse outcomes. We tested the hypothesis that not all patients with an anastomotic leak after bariatric surgery present with clinical symptoms and that their outcome is dependent on the aggressiveness of the host inflammatory response. This was a retrospective analysis of prospectively collected clinical data from 2384 bariatric surgeries from 1983 to 2006. All anastomotic leaks were identified from the database, and the vital signs, hematologic and biochemical data, mode of diagnosis, treatment, and outcome were recorded and analyzed. We identified 55 anastomotic leaks (2.3%) at a median of 4 days (range 1-26) after surgery. In 37 patients (67.3%), the leaks were identified at a median of 5 days (range 1-26) postoperatively because of clinical signs and symptoms of a systemic inflammatory response (SIRS leaks). In contrast, in 18 patients (32.7%), the leaks were identified at a median of 1.5 days (range 1-16) postoperatively only after routine contrast studies (non-SIRS leaks). Treatment included antibiotics and open drainage in 41.8%, laparoscopic drainage in 21.8%, computed tomography-guided drainage in 12.7%, conservative treatment in 14.5%, and other in 9.2%. All 6 deaths (4 men and 2 women, 10.9%) occurred in the SIRS group. Using logistic regression analysis, temperature (inflammatory response) and body mass index were independent predictors of mortality. The results of our study have shown that one third of patients with anastomotic leaks after bariatric surgery present with minimal clinical symptoms (non-SIRS) and are only detected if contrast studies are performed. Such leaks are unlikely to lead to death. Two thirds of patients with anastomotic leaks present with a systemic inflammatory response to the leak. Such leaks require urgent treatment that might not always prevent death.

  16. Development of a General Method for Determining Leak Rates from Limiting Enclosures

    Science.gov (United States)

    Zografos, A. I.; Blackwell, C. C.; Harper, Lynn D. (Technical Monitor)

    1994-01-01

    This paper discusses the development of a general method for the determination of very low leak rates from limiting enclosures. There are many methods that can be used to detect and repair leaks from enclosures. Many methods have also been proposed that allow the estimation of actual leak rates, usually expressed as enclosure volume turnover. The proposed method combines measurements of the state variables (pressure, temperature, and volume) as well as the change in the concentration of a tracer gas to estimate the leak rate. The method was applied to the containment enclosure of the Engineering Development Unit of the CELSS Test Facility, currently undergoing testing at the NASA Ames Research Center.

  17. Pressure based leak detection system implanted on the business Unit Exploration and Production of PETROBRAS in Rio Grande do Norte e Ceara; Sistema de deteccao de vazamentos em dutos baseado em pressao implantado na Unidade de Negocios de Exploracao e Producao da PETROBRAS no Rio de Grande do Norte e Ceara

    Energy Technology Data Exchange (ETDEWEB)

    Rolim, Tuerte A.; Oliveira, Abenildo A.de [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2003-07-01

    This paper presents the experience faced by people who works in PETROBRAS Business Unit (UN-RNCE), located in Rio Grande do Norte Province, Brazil, during the implementation of a pipeline leak detection system. That application involved nine multiphase oil pipelines distributed along several production facilities. Because of the emergency after the leakage that polluted the Guanabara bay and due to the two phases and multi phases pipelines characteristics, the UN-RNCE decided to apply the Pressure Point Analysis (PPA) technology in order to detect leakages. It is a statistical method for leak detection e uses a very simple instrumentation which facilitates the installation and maintenance. However, in order to get the best performance of the system, it is necessary to know thoroughly the whole process and have a fast and reliable SCADA system for long distance communication. Finally it will be shown the test results, the recommendations to expand the system and the conclusions. (author)

  18. Fugitive methane leak detection using mid-infrared hollow-core photonic crystal fiber containing ultrafast laser drilled side-holes

    Science.gov (United States)

    Karp, Jason; Challener, William; Kasten, Matthias; Choudhury, Niloy; Palit, Sabarni; Pickrell, Gary; Homa, Daniel; Floyd, Adam; Cheng, Yujie; Yu, Fei; Knight, Jonathan

    2016-05-01

    The increase in domestic natural gas production has brought attention to the environmental impacts of persistent gas leakages. The desire to identify fugitive gas emission, specifically for methane, presents new sensing challenges within the production and distribution supply chain. A spectroscopic gas sensing solution would ideally combine a long optical path length for high sensitivity and distributed detection over large areas. Specialty micro-structured fiber with a hollow core can exhibit a relatively low attenuation at mid-infrared wavelengths where methane has strong absorption lines. Methane diffusion into the hollow core is enabled by machining side-holes along the fiber length through ultrafast laser drilling methods. The complete system provides hundreds of meters of optical path for routing along well pads and pipelines while being interrogated by a single laser and detector. This work will present transmission and methane detection capabilities of mid-infrared photonic crystal fibers. Side-hole drilling techniques for methane diffusion will be highlighted as a means to convert hollow-core fibers into applicable gas sensors.

  19. The leak microstructure

    Indian Academy of Sciences (India)

    M Lombardi; C Baiocchi; A Battistella; G Balbinot; H Huo-Ja Guoxiang; F S Lombardi

    2001-07-01

    The capabilities of a new microstructure, anode point based, for the detection of gas ionizing radiations are presented. For every single detected ionizing radiation it gives a pair of ‘induced’ charges (anodic and cathodic) of the same amount (pulses of the same amplitudes), of opposite sign, with the same collection time and essentially in time coincidence, that are proportional to the primary ionization collected. Each pulse of a pair gives the same energy and timing information, thus one can be used for these information and the other for the position. The complete lack of insulating materials in the active volume of this microstructure avoids problems of charging-up and makes stable and repeatable its behavior. It is possible to observe primary avalanches with a size of more than 2.5 × 107 electrons (4 pC), which give current pulses with a peak of more than 0.26 mA on 100 Ohm and about 30 ns duration, with 5.9 KeV X-rays of 55Fe working in proportional region in 760 Torr of isobutane gas. Single electrons emitted by a heated filament ( < 1~ eV) can also be detected in 760 Torr of isobutane; with an estimated gas gain of 1.2 × 106 and a counting rate up to 800 Kpulses/sec per single microstructure. Some new features and three different types of sensitive-position two-dimensional read-out detectors based on these microstructures, which are in developmental stage, are presented.

  20. Presidential Leaks: Rhetoric and Mediated Political Knowledge.

    Science.gov (United States)

    Erickson, Keith V.

    1989-01-01

    Argues that presidential leaks constitute rhetorical acts, enabling administrations to exercise a variety of rhetorically potent options not afforded by the public forum. Proposes a typology of presidential leaks and analyzes their rhetorical functions, benefits, and liabilities. (MM)

  1. Stochastic Consequence Analysis for Waste Leaks

    Energy Technology Data Exchange (ETDEWEB)

    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. CT findings suggesting anastomotic leak and predicting the recovery period following gastric surgery

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Ho; Kim, Jung Hoon; Shin, Cheong-Il; Kim, Se Hyung; Han, Joon Koo; Choi, Byung Ihn [Seoul National University College of Medicine, Department of Radiology, Institute of Radiation Medicine, Jongno-gu, Seoul (Korea, Republic of)

    2015-07-15

    To assess diagnostic performance of routine CT for detecting anastomotic leak after gastric surgery, and analyse the relationship between recovery period and CT findings. We included 179 patients who underwent immediate CT and fluoroscopy after gastric surgery. Two reviewers retrospectively rated the possibility of leak on CT using a five-point scale focused on predefined CT findings. They also evaluated CT findings. Patients were categorised as: Group I, leak on fluoroscopy; Group II, possible leak on CT but negative on fluoroscopy; Group III, no leak. We analysed the relationship between recovery period and group. Area under the curve for detecting leak on CT was 0.886 in R1 and 0.668 in R2 with moderate agreement (k = 0.482). Statistically common CT findings for leak included discontinuity, large amount of air-fluid and wall thickening at anastomosis site (p < 0.05). Discontinuity at anastomosis site and a large air-fluid collection were independently associated with leak (p < 0.05). The recovery period including hospitalisation and postoperative fasting period was longer in Group I than Group II or III (p < 0.05). Group II showed a longer recovery period than Group III (p < 0.05). Postoperative routine CT was useful for predicting anastomotic leak using specific findings, and for predicting length of recovery period. (orig.)

  3. Investigation on the sodium leak accident of Monju. Sodium leak test simulating the Monju leak

    Energy Technology Data Exchange (ETDEWEB)

    Shimoyama, Kazuhito; Nishimura, Masahiro; Miyahara, Shinya; Miyake, Osamu; Tanabe, Hiromi [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center; Usami, Masayuki

    1996-11-01

    Sodium fire experiments were carried out two times using the Sodium Fire Test Rig (SOFT-1) in the Power Reactor and Nuclear Fuel Development Corp (PNC) as a part of works to research the cause of the accident in secondary main cooling system of Monju. The purposes of these experiments are to confirm the leak rate and leakage form of sodium from damaged thermometer, to confirm the damage to the piping insulating structure around the thermometer and to the flexible tube, and to compare the temperature history of the signal from the thermometer between the experiments and Monju. In the experiments 56({+-}2)g/sec was obtained as the leak rate under the condition of ensuring the leakage pass in the simulated thermometer. This leak rate was corrected to 53g/sec to take account of manufacturing error of the thermometer between the experiment and Monju. In calculation of this leak rate, it is assumed that the annulus size of thermometer well tip is a nominal distance and pressure value to the leakage sodium is 1.65kg/cm{sup 2}G, which was the maximum one during the leakage of Monju. The behavior of signal from the simulated thermometer was very similar to that of the damaged thermometer in Monju and it was confirmed this temperature history could be sufficiently explained by moving of the temperature contact position of the thermocouple following the runoff of leakage sodium. (J.P.N.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Faidy, C. [EDF SEPTEN, Villeurbanne (France)

    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.

  5. Leak signature space: an original representation for robust leak location in water distribution networks

    OpenAIRE

    Casillas, Myrna V.; Garza-Castañón, Luis E.; Vicenç Puig; Adriana Vargas-Martinez

    2015-01-01

    In this paper, an original model-based scheme for leak location using pressure sensors in water distribution networks is introduced. The proposed approach is based on a new representation called the Leak Signature Space (LSS) that associates a specific signature to each leak location being minimally affected by leak magnitude. The LSS considers a linear model approximation of the relation between pressure residuals and leaks that is projected onto a selected hyperplane. This new approach allo...

  6. Leaking electricity in domestic appliances

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. 基于RBF神经网络的天然气管道泄漏检测技术研究%The natural gas pipeline leak detection technology based on RBF neural network research

    Institute of Scientific and Technical Information of China (English)

    高丙坤; 郑仁谦; 尹淑欣; 张莉; 岳武峰

    2016-01-01

    为了正确判断管道是否发生泄漏,本文采用混合学习方法对网络进行训练学习。通过将管道运行参数作为神经网络的输入,管道运行状态作为神经网络的输出,实现两者的非线性映射,以此来判断输入信号是否为泄漏信号,并选用K-means聚类方法和递推最小二乘法来确定网络参数。通过用天然气管道运行的实测数据对RBF神经网络进行了训练和测试,得到结果误差在可接受的范围内,从而证明RBF神经网络的方法可用于天然气管道泄漏检测的研究。%In order to correctly determine whether pipeline leakage occurs, this paper adopts a hybrid learning method for network training. We set the pipeline operation parameters as the input of neural network and running status of the pipe as the neural network output, realizing the two nonlinear mapping, in order to determine whether the input signal is leakage signal , and select K-means clustering method and the recursive least square method to determine the network parameters. With the measurements of the gas pipeline operation on training and testing the RBF neural network, we get the results in an acceptable error range, which prove that the method of RBF neural network can be used for natural gas pipeline leak detection.

  8. DETECCIÓN DE PÉRDIDAS EN TUBERÍAS DE AGUA: PROPUESTA BASADA EN UN BANCO DE FILTROS LEAK DETECTION IN WATER PIPELINES: PROPOSAL BASED ON A BANK OF FILTERS

    Directory of Open Access Journals (Sweden)

    Lucía Castro Burgos

    2009-12-01

    Full Text Available Actualmente la detección de pérdidas (DP en tuberías de agua es un área de investigación activa, y con un creciente interés, debido a la importancia del transporte seguro del vital elemento. Este trabajo considera el problema de DP en tuberías de agua por medio de redundancia analítica, basada en un modelo matemático y utilizando técnicas de estimación de estados, teniendo por objetivo principal estudiar, proponer, implementar y aplicar algoritmos eficientes que permitan abordar de manera general el problema de DP. Para lograr esto se propone y evalúa un banco de filtros, implementados con filtros de Kalman (FK y filtros de partículas (FP. Con esto se busca contribuir conceptualmente a la formulación del problema de DP, de manera modular, permitiendo que en un estudio futuro otras técnicas puedan ser utilizadas para resolver el problema. Además, obtener algoritmos eficientes y confiables, basados en un estimador de estados capaces de responder a requerimientos industriales, tales como: entregar, a partir de medidas de entrada y salida disponibles, una estimación fiable del estado del proceso, esto con independencia de la dinámica lineal o no lineal, asimismo, ser de fácil manejo y fácil configuración. La simulación computacional y los resultados experimentales muestran la efectividad de combinar FP con FK, para el caso básico de dos pérdidas secuenciales en una tubería, presentando ventajas de rápida convergencia y reducción del error de estimación, factores importantes en el problema de DP en ductos hídricos.Currently leak detection (LD in water pipelines is an active area of research that is attracting increasing interest due to the importance of the safe transport of this vital resource. This work considers the problem of LD in water pipes by means of analytical redundancy, based on a mathematical model and using state estimation techniques. The main aim of this work is to research, propose, implement and apply

  9. Imaging with the leak microstructures: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Baiocchi, C.; Balbinot, G; Battistella, A.; Galeazzi, G.; Lombardi, F.S.; Lombardi, M. E-mail: mariano.lombardi@lnl.infn.it; Prete, G.; Simon, A

    2004-02-01

    We report on some images obtained with the Leak Microstructures (LM), which are elements for the detection of gas ionizing particles based on needle-point anodes. X-ray images of a mask with seven holes, 300 {mu}m in diameter and 100 {mu}m separated, drilled on a tantalum sheet were obtained with a very good spatial resolution. Varying the potential to the drifting electrode we put in evidence the possibility to perform a 'zoom' of the image. X-ray images of a tantalum sheet of about 20x20 mm{sup 2} were obtained using a matrix of 9x9 LMs read by only 6 electronic chains (6 ADCs)

  10. Analyzing User Awareness of Privacy Data Leak in Mobile Applications

    Directory of Open Access Journals (Sweden)

    Youngho Kim

    2015-01-01

    Full Text Available To overcome the resource and computing power limitation of mobile devices in Internet of Things (IoT era, a cloud computing provides an effective platform without human intervention to build a resource-oriented security solution. However, existing malware detection methods are constrained by a vague situation of information leaks. The main goal of this paper is to measure a degree of hiding intention for the mobile application (app to keep its leaking activity invisible to the user. For real-world application test, we target Android applications, which unleash user privacy data. With the TaintDroid-ported emulator, we make experiments about the timing distance between user events and privacy leaks. Our experiments with Android apps downloaded from the Google Play show that most of leak cases are driven by user explicit events or implicit user involvement which make the user aware of the leakage. Those findings can assist a malware detection system in reducing the rate of false positive by considering malicious intentions. From the experiment, we understand better about app’s internal operations as well. As a case study, we also presents a cloud-based dynamic analysis framework to perform a traffic monitor.

  11. Leak-Tight Welding Experience from the Industrial Assembly of the LHC Cryostats at CERN

    CERN Document Server

    Bourcey, N; Chiggiato, P; Limon, P; Mongelluzzo, A; Musso, G; Poncet, A; Parma, V

    2008-01-01

    The assembly of the approximately 1700 LHC main ring cryostats at CERN involved extensive welding of cryogenic lines and vacuum vessels. More than 6 km of welding requiring leak tightness to a rate better than 1.10-9 mbar.l.s-1 on stainless steel and aluminium piping and envelopes was made, essentially by manual welding but also making use of orbital welding machines. In order to fulfil the safety regulations related to pressure vessels and to comply with the leak-tightness requirements of the vacuum systems of the machine, welds were executed according to high qualification standards and following a severe quality assurance plan. Leak detection by He mass spectrometry was extensively used. Neon leak detection was used successfully to locate leaks in the presence of helium backgrounds. This paper presents the quality assurance strategy adopted for welds and leak detection. It presents the statistics of non-conformities on welds and leaks detected throughout the entire production and the advances in the use...

  12. Quantitative Techniques in Volumetric Analysis

    Science.gov (United States)

    Zimmerman, John; Jacobsen, Jerrold J.

    1996-12-01

    Quantitative Techniques in Volumetric Analysis is a visual library of techniques used in making volumetric measurements. This 40-minute VHS videotape is designed as a resource for introducing students to proper volumetric methods and procedures. The entire tape, or relevant segments of the tape, can also be used to review procedures used in subsequent experiments that rely on the traditional art of quantitative analysis laboratory practice. The techniques included are: Quantitative transfer of a solid with a weighing spoon Quantitative transfer of a solid with a finger held weighing bottle Quantitative transfer of a solid with a paper strap held bottle Quantitative transfer of a solid with a spatula Examples of common quantitative weighing errors Quantitative transfer of a solid from dish to beaker to volumetric flask Quantitative transfer of a solid from dish to volumetric flask Volumetric transfer pipet A complete acid-base titration Hand technique variations The conventional view of contemporary quantitative chemical measurement tends to focus on instrumental systems, computers, and robotics. In this view, the analyst is relegated to placing standards and samples on a tray. A robotic arm delivers a sample to the analysis center, while a computer controls the analysis conditions and records the results. In spite of this, it is rare to find an analysis process that does not rely on some aspect of more traditional quantitative analysis techniques, such as careful dilution to the mark of a volumetric flask. Figure 2. Transfer of a solid with a spatula. Clearly, errors in a classical step will affect the quality of the final analysis. Because of this, it is still important for students to master the key elements of the traditional art of quantitative chemical analysis laboratory practice. Some aspects of chemical analysis, like careful rinsing to insure quantitative transfer, are often an automated part of an instrumental process that must be understood by the

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

    Energy Technology Data Exchange (ETDEWEB)

    Kovach, B.J.; Banks, E.M.; Wikoff, W.O. [NUCON International, Inc., Columbus, OH (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-08-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-02-01

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

  16. Test Facility for Volumetric Absorber

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, M.; Dibowski, G.; Pfander, M.; Sack, J. P.; Schwarzbozl, P.; Ulmer, S.

    2006-07-01

    Long-time testing of volumetric absorber modules is an inevitable measure to gain the experience and reliability required for the commercialization of the open volumetric receiver technology. While solar tower test facilities are necessary for performance measurements of complete volumetric receivers, the long-term stability of individual components can be tested in less expensive test setups. For the qualification of the aging effects of operating cycles on single elements of new absorber materials and designs, a test facility was developed and constructed in the framework of the KOSMOSOL project. In order to provide the concentrated solar radiation level, the absorber test facility is integrated into a parabolic dish system at the Plataforma Solar de Almeria (PSA) in Spain. Several new designs of ceramic absorbers were developed and tested during the last months. (Author)

  17. ISOLDE Off-line Gas Leak Upgrade

    CERN Document Server

    Nielsen, Kristoffer Bested

    2017-01-01

    This study investigates gas injection system of the ISOLDE Off-line separator. A quadrupole mass spectrometer is used to analysis the composition of the gas. Based on these measurements a contamination of the injected gas is found and a system upgrade is purposed. Furthermore a calibration of the leak rate of the leak valve is made.

  18. Strength and leak testing of plasma activated bonded interfaces

    DEFF Research Database (Denmark)

    Visser, M.M.; Weichel, Steen; Reus, Roger De

    2002-01-01

    Bond strength and hermeticity of plasma activated bonded (PAB) Si-Si interfaces are reported. Bonding of 100 mm Si(1 0 0) wafers was performed. An average bond strength of 9.0+/-3.9 MPa was achieved without performing any annealing steps. Cavities bonded in vacuum were found to be hermetic based...... on detection of changes in membrane deflections. The detection limit for leak was 8E-13 mbar l/s. For comparison, strength and leak tests were also performed with regular fusion bonded wafers annealed at 1100 degreesC. The PAB was found to withstand post-processing steps such as RCA cleaning, 24 h in de......-ionised water (DIW), 24 h in 2.5% HF, 24 h in acetone and 60 s in a resist developer. By analysing the thin silicon oxide present on the surfaces to be bonded with optical methods, the influence of pre-cleaning and activation process parameters was investigated....

  19. Successful Endoscopic Therapy of Traumatic Bile Leaks

    Directory of Open Access Journals (Sweden)

    Matthew P. Spinn

    2013-02-01

    Full Text Available Traumatic bile leaks often result in high morbidity and prolonged hospital stay that requires multimodality management. Data on endoscopic management of traumatic bile leaks are scarce. Our study objective was to evaluate the efficacy of the endoscopic management of a traumatic bile leak. We performed a retrospective case review of patients who were referred for endoscopic retrograde cholangiopancreatography (ERCP after traumatic bile duct injury secondary to blunt (motor vehicle accident or penetrating (gunshot trauma for management of bile leaks at our tertiary academic referral center. Fourteen patients underwent ERCP for the management of a traumatic bile leak over a 5-year period. The etiology included blunt trauma from motor vehicle accident in 8 patients, motorcycle accident in 3 patients and penetrating injury from a gunshot wound in 3 patients. Liver injuries were grade III in 1 patient, grade IV in 10 patients, and grade V in 3 patients. All patients were treated by biliary stent placement, and the outcome was successful in 14 of 14 cases (100%. The mean duration of follow-up was 85.6 days (range 54-175 days. There were no ERCP-related complications. In our case review, endoscopic management with endobiliary stent placement was found to be successful and resulted in resolution of the bile leak in all 14 patients. Based on our study results, ERCP should be considered as first-line therapy in the management of traumatic bile leaks.

  20. Leveraging Social Norms to Improve Leak Resolution Outcomes Across Meter Classes:

    Science.gov (United States)

    Holleran, W.

    2016-12-01

    Over the past decade, utilities, governments, businesses, and nonprofits have come to realize that more than just financial considerations and information drive behavior. Social and psychological factors also play a significant role in shaping consumers' decisions and behaviors around resource use. Stakeholders have consequently turned their interest to behavioral science, a multidisciplinary field that draws from psychology, sociology, public health, and behavioral economics to explain the complex mechanisms that shape human behavior. When used strategically, behavioral science holds the potential to drive down resource use, drive up profits, and generate measurable gains in conservation and efficiency. WaterSmart will present on how the water sector can employ behavioral science to nudge residential rate-payers to use water more efficiently and help them save money. Utilities can use behavioral science to influence people's reaction to leaks. 5% of Single Family Residential (SFR) metered water use can be attributed to leaks. This value potentially skews even higher for MultiFamily (MF) and Commercial accounts given that it can get lost in the noise of daily consumption. Existing leak detection algorithms in the market are not sophisticated enough to detect leaks for a MF or Commercial property. Leveraging data from utilities on known leak events at MF and Commercial buildings allowed WaterSmart to train a machine learning model to identify key features in the load shape and accurately detect these types of water use events. The outcome of the model is a leak amount and confidence level for each irregular usage event. The model also incorporates record feedback from users on the type of leak event, and the accuracy of the alert. When WaterSmart leverages this data model with social norms messaging, we've been able to improve water demand management for MF and Commercial properties. Experiences from leak detection and resolution in the SFR space will also be

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

    Energy Technology Data Exchange (ETDEWEB)

    Woronowicz, Michael; Blackmon, Rebecca; Brown, Martin [Stinger Ghaffarian Technologies, Inc, 7701 Greenbelt Rd, Greenbelt, MD 20770 (United States); Abel, Joshua; Hawk, Doug [Alliant Techsystems, Inc, 5050 Powder Mill Road, Beltsville, Maryland 20705 (United States); Autrey, David; Glenn, Jodie [Lockheed Martin, 1300 Hercules, Houston, TX 77058 (United States); Bond, Tim; Buffington, Jesse [NASA Johnson Space Flight Center, 2101 NASA Pkwy, Houston, TX 77058 (United States); Cheng, Edward; Ma, Jonathan; Rossetti, Dino [Conceptual Analytics, 8209 Woburn Abbey Rd, Glenn Dale, MD 20769 (United States); DeLatte, Danielle [ASRC Federal Space and Defense, 7000 Muirkirk Meadows Drive, Suite 100, Beltsville, MD 20705 (United States); Garcia, Kelvin; Mohammed, Jelila; Montt de Garcia, Kristina; Perry, Radford [NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771 (United States); Tull, Kimathi [Jackson and Tull, 7375 Executive Pl, Lanham, MD 20706 (United States); Warren, Eric [Wyle STE Group, 1290 Hercules Ave, Houston, TX 77058-2769 (United States)

    2014-12-09

    The International Space Station program is developing a robotically-operated leak locator tool to be used externally. The tool would consist of a Residual Gas Analyzer for partial pressure measurements and a full range pressure gauge for total pressure measurements. The primary application is to demonstrate the ability to detect NH{sub 3} coolant leaks in the ISS thermal control system. An analytical model of leak plume physics is presented that can account for effusive flow as well as plumes produced by sonic orifices and thruster operations. This model is used along with knowledge of typical RGA and full range gauge performance to analyze the expected instrument sensitivity to ISS leaks of various sizes and relative locations (“directionality”). The paper also presents experimental results of leak simulation testing in a large thermal vacuum chamber at NASA Goddard Space Flight Center. This test characterized instrument sensitivity as a function of leak rates ranging from 1 lb{sub m/}/yr. to about 1 lb{sub m}/day. This data may represent the first measurements collected by an RGA or ion gauge system monitoring off-axis point sources as a function of location and orientation. Test results are compared to the analytical model and used to propose strategies for on-orbit leak location and environment characterization using the proposed instrument while taking into account local ISS conditions and the effects of ram/wake flows and structural shadowing within low Earth orbit.

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

    Science.gov (United States)

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

    2014-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  4. Leaking Underground Storage Tank Sites in Iowa

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — Leaking Underground Storage Tank (LUST) sites where petroleum contamination has been found. There may be more than one LUST site per UST site.

  5. Leaking Underground Storage Tank (LUST) Trust Fund

    Science.gov (United States)

    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.

  6. WikiLeaks: neue Dimensionen des Medienaktivismus

    OpenAIRE

    Stalder, Felix

    2011-01-01

    "Mit WikiLeaks hat der Medienaktivismus eine neue Dimension erreicht. WikiLeaks versteht die neuen sozio-technischen Möglichkeiten und institutionellen Widersprüche, die die gegenwärtige Phase der Entwicklung der Netzwerkgesellschaft kennzeichnen, für sein Projekt nutzbar zu machen. Politisch bleibt das Projekt allerdings schwer kategorisierbar, da es gleichzeitig eine markt-libertäre und eine institutionskritische Haltung vertritt, gleichermassen staatliche wie privat-wirtscha...

  7. Analysis of Pressurized Water Reactor Primary Coolant Leak Events Caused by Thermal Fatigue

    Energy Technology Data Exchange (ETDEWEB)

    Atwood, Corwin Lee; Shah, Vikram Naginbhai; Galyean, William Jospeh

    1999-09-01

    We present statistical analyses of pressurized water reactor (PWR) primary coolant leak events caused by thermal fatigue, and discuss their safety significance. Our worldwide data contain 13 leak events (through-wall cracking) in 3509 reactor-years, all in stainless steel piping with diameter less than 25 cm. Several types of data analysis show that the frequency of leak events (events per reactor-year) is increasing with plant age, and the increase is statistically significant. When an exponential trend model is assumed, the leak frequency is estimated to double every 8 years of reactor age, although this result should not be extrapolated to plants much older than 25 years. Difficulties in arresting this increase include lack of quantitative understanding of the phenomena causing thermal fatigue, lack of understanding of crack growth, and difficulty in detecting existing cracks.

  8. Volumetric Three-Dimensional Display Systems

    Science.gov (United States)

    Blundell, Barry G.; Schwarz, Adam J.

    2000-03-01

    A comprehensive study of approaches to three-dimensional visualization by volumetric display systems This groundbreaking volume provides an unbiased and in-depth discussion on a broad range of volumetric three-dimensional display systems. It examines the history, development, design, and future of these displays, and considers their potential for application to key areas in which visualization plays a major role. Drawing substantially on material that was previously unpublished or available only in patent form, the authors establish the first comprehensive technical and mathematical formalization of the field, and examine a number of different volumetric architectures. System level design strategies are presented, from which proposals for the next generation of high-definition predictable volumetric systems are developed. To ensure that researchers will benefit from work already completed, they provide: * Descriptions of several recent volumetric display systems prepared from material supplied by the teams that created them * An abstract volumetric display system design paradigm * An historical summary of 90 years of development in volumetric display system technology * An assessment of the strengths and weaknesses of many of the systems proposed to date * A unified presentation of the underlying principles of volumetric display systems * A comprehensive bibliography Beautifully supplemented with 17 color plates that illustrate volumetric images and prototype displays, Volumetric Three-Dimensional Display Systems is an indispensable resource for professionals in imaging systems development, scientific visualization, medical imaging, computer graphics, aerospace, military planning, and CAD/CAE.

  9. Evaluation of methodologies for the calculation of leak rates for pressure retaining components with crack-like leaks; Bewertung von Methoden zur Berechnung von Leckraten fuer druckfuehrende Komponenten mit rissartigen Lecks

    Energy Technology Data Exchange (ETDEWEB)

    Sievers, Juergen; Heckmann, Klaus; Blaesius, Christoph

    2015-06-15

    For the demonstration of break preclusion for pressure retaining components in nuclear power plants, the nuclear safety standard KTA 3206 determines also the requirements for the leak-before-break verification. For this procedure, it has to be ensured that a wall-penetrating crack is subcritical with respect to instable growth, and that the resulting leakage under stationary operation conditions can be detected by a leak detection system. Within the scope of the project 3613R01332 analyses with respect to conservative estimates of the leak rates in case of detections regarding break preclusion were performed by means of leak rate models being available at GRS. For this purpose, conservative assumptions in the procedure were quantified by comparative calculations concerning selected leak rate experiments and the requirements regarding the determination of leak rates indicated in the KTA 3206 were verified and specified. Moreover, the models were extended and relevant recommendations for the calculation procedure were developed. During the investigations of leak rate tests the calculation methods were validated, qualified by means of both examples indicated in KTA 3206 and applied to a postulated leak accident in the cooling circuit of a PWR. For the calculation of leak rates several simplified solution methods which are included in the GRS program WinLeck were applied, and for the simulation of a leak accident the large-scale programs ANSYS Mechanical and ATHLET (thermohydraulics program developed by GRS) were used. When applying simplified methods for the calculation of leak rates using the limiting curve for the friction factor which has been derived during the project and which is included in the KTA 3206 attention has to be paid to the fact that in case of small flow lengths the entrance loss can dominate compared to the friction loss. However, the available data do not suffice in order to make a quantitative statement with respect to limits of applicability

  10. Leaks in the internal water supply piping systems

    Directory of Open Access Journals (Sweden)

    Orlov Evgeniy Vladimirovich

    2015-03-01

    Full Text Available Great water losses in the internal plumbing of a building lead to the waste of money for a fence, purification and supply of water volumes in excess. This does not support the concept of water conservation and resource saving lying today in the basis of any building’s construction having plumbing. Leakage means unplanned of water losses systems in domestic water supply systems (hot or cold as a result of impaired integrity, complicating the operation of a system and leading to high costs of repair and equipment restoration. A large number of leaks occur in old buildings, where the regulatory service life of pipelines has come to an end, and the scheduled repair for some reason has not been conducted. Steel pipelines are used in the systems without any protection from corrosion and they get out of order. Leakages in new houses are also not uncommon. They usually occur as a result of low-quality adjustment of the system by workers. It also important to note the absence of certain skills of plumbers, who don’t conduct the inspections of in-house systems in time. Sometimes also the residents themselves forget to keep their pipeline systems and water fittings in their apartment in good condition. Plumbers are not systematically invited for preventive examinations to detect possible leaks in the domestic plumbing. The amount of unproductive losses increases while simultaneous use of valve tenants, and at the increase of the number of residents in the building. Water leaks in the system depend on the amount of water system piping damages, and damages of other elements, for example, water valves, connections, etc. The pressure in the leak area also plays an important role.

  11. Biliary leaks after laparoscopic cholecystectomy:timetostentortimetodrain

    Institute of Scientific and Technical Information of China (English)

    Haim Pinkas; Patrick G. Brady

    2008-01-01

    BACKGROUND: Endoscopic retrograde cholangiopan-creatography (ERCP) with placement of a biliary stent or nasobiliary (NB) drain is the procedure of choice for treatment of post-cholecystectomy bile duct leaks. The aim of this study was to compare the effect of NB drainage versus internal biliary stenting on rates of leak closure, time elapsed until drain or stent removal, length of hospital stay and number of required endoscopic procedures. METHODS: Charts were reviewed on 20 patients who underwent laparoscopic cholecystectomy complicated by Luschka or cystic duct leak. Ten patients were treated with NB drains connected to low intermittent suction and repeat NB cholangiograms were performed until leak closure was observed. Ten patients were treated with internal biliary stents. Biliary sphincterotomies were performed for stone extraction or a presumed papillary stenosis. Large bilomas were drained percutaneously prior to stenting. RESULTS: In all 20 patients, a cholangiogram and successful placement of a NB drain or internal stent was achieved. Four patients (20%) were found to have bile duct stones, which were extracted following a sphincterotomy. Sixteen patients required percutaneous drains to evacuate large bilomas prior to biliary instrumentation. Fifteen cystic duct leaks and 5 Luschka duct leaks were reviewed. There were no complications related to ERCP. Closure of the leak was documented within 2 to 11 days (mean 4.7±0.9 days) in patients receiving a NB drain. The drains were removed non-endoscopically following leak closure. The internal stent group required stenting for 14 to 53 days (mean 29.1±4.4 days). The stent was then removed endoscopically after documentation of leak closure. Bile leaks following laparoscopic cholecystectomy closed rapidly after NB drainage and did not require repeat endoscopy for removal of the NB drain, resulting in fewer ERCPs required for treatment of biliary leaks. Internal biliary stents were in place longer owing

  12. Demonstration of leak-before-break in Japan Sodium cooled Fast Reactor (JSFR) pipes

    Energy Technology Data Exchange (ETDEWEB)

    Wakai, Takashi, E-mail: wakai.takashi@jaea.go.jp [Japan Atomic Energy Agency, 4002 Narita-cho, O-arai, Ibaraki 311 1393 (Japan); Machida, Hideo; Yoshida, Shinji [TEPCO Systems Corporation, 2-37-28 Eitai, Koto-ku, Tokyo 135 0034 (Japan); Xu, Yang [Mitsubishi FBR Systems, Inc., 2-34-17 Jingumae, Shibuya-ku, Tokyo 150 0001 (Japan); Tsukimori, Kazuyuki [Japan Atomic Energy Agency, 4002 Narita-cho, O-arai, Ibaraki 311 1393 (Japan)

    2014-04-01

    This paper describes the leak-before-break (LBB) assessment procedure applicable to Japan Sodium cooled Fast Reactor (JSFR) pipes made of modified 9Cr–1Mo steel. For the sodium pipes of JSFR, the continuous leak monitoring will be adopted as an alternative to a volumetric test of the weld joints under conditions that satisfy LBB. Firstly, a LBB assessment flowchart eliminating uncertainty resulted from small scale leakage, such as self plugging phenomenon and influence of crack surface roughness on leak rate, was proposed. Secondly, a rational unstable fracture assessment technique, taking the compliance changing with crack extension into account, was also proposed. Thirdly, a crack opening displacement (COD) assessment technique was developed, because COD assessment method applicable to JSFR pipes – thin wall and small work hardening material – had not been proposed yet. In addition, fracture toughness tests were performed using compact tension (CT) specimens to obtain the fracture toughness, J{sub IC}, and the crack growth resistance (J–R) curve at elevated temperature. Finally, by using the flowchart, proposed techniques and collected data, LBB assessment for the primary sodium pipes of JSFR was conducted. As a result, LBB aspect was successfully demonstrated with sufficient margins.

  13. Escape dynamics through a continuously growing leak

    Science.gov (United States)

    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.

  14. Development of a Miniaturized and Portable Methane Analyzer for Natural Gas Leak Walking Surveys

    Science.gov (United States)

    Huang, Y. W.; Leen, J. B.; Gupta, M.; Baer, D. S.

    2016-12-01

    Traditional natural gas leak walking surveys have been conducted with devices that are based on technologies such as flame ionization detector (FID), IR-based spectrometer and IR camera. The sensitivity is typically on the ppm level. The low sensitivity means the device cannot pick up leaks far from it, and more time is spent surveying the area before pinpointing the leak location. A miniaturized methane analyzer has been developed to significantly improve the sensitivity of the device used in walking surveys to detect natural gas leaks at greater distance. ABB/LGR's patented Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) is utilized to offer rugged and highly sensitive methane detection in a portable package. The miniaturized package weighs 13.5 lb, with a 4-hour rechargeable battery inside. The precision of the analyzer for methane is 2 ppb at 1 second. The analyzer operates at 10 Hz and its flow response time is 3 seconds for measurements through a 1-meter long sampling wand to registering on the data stream. The data can be viewed in real-time on a tablet or a smartphone. The compact and simplified package of the methane analyzer allows for more efficient walking surveys. It also allows for other applications that require low-power, low-weight and a portable package. We present data from walking surveys to demonstrate its ability to detect methane leaks.

  15. CT assessment of anastomotic bowel leak

    Energy Technology Data Exchange (ETDEWEB)

    Power, N. [Department of Radiology, Sunnybrook Hospital, Toronto, Ontario M4N 3M5 (Canada); Atri, M. [Department of Radiology, Sunnybrook Hospital, Toronto, Ontario M4N 3M5 (Canada)]. E-mail: mostafa.atri@sw.ca; Ryan, S. [Department of Radiology, Sunnybrook Hospital, Toronto, Ontario M4N 3M5 (Canada); Haddad, R. [Department of Surgery, Sunnybrook Hospital, Toronto, Ontario M4N 3M5 (Canada); Smith, A. [Department of Surgery, Sunnybrook Hospital, Toronto, Ontario M4N 3M5 (Canada)

    2007-01-15

    Aim: To evaluate the predictors of clinically important gastrointestinal anastomotic leaks using multidetector computed tomography (CT). Subjects and methods: Ninety-nine patients, 73 with clinical suspicion of anastomotic bowel leak and 26 non-bowel surgery controls underwent CT to investigate postoperative sepsis. Fifty patients had undergone large bowel and 23 small bowel anastomoses. The time interval from surgery was 3-30 days (mean 10 {+-} 5.9 SD) for the anastomotic group and 3-40 days (mean 14 {+-} 11 SD) for the control group (p = 0.3). Two radiologists blinded to the final results reviewed the CT examinations in consensus and recorded the presence of peri-anastomotic air, fluid or combination of the two; distant loculated fluid or combination of fluid and air; free air or fluid; and intestinal contrast leak. Final diagnosis of clinically important anastomotic leak (CIAL) was confirmed at surgery or by chart review of predetermined clinical and laboratory criteria. Results: The prevalence of CIAL in the group undergoing CT was 31.5% (23/73). The CT examinations with documented leak were performed 5-28 (mean; 11.4 {+-} 6 SD) days after surgery. Nine patients required repeat operation, 10 percutaneous abscess drainage, two percutaneous drainage followed by surgery, and two prolonged antibiotic treatment and total parenteral nutrition (TPN). Of the CT features examined, only peri-anastomotic loculated fluid containing air was more frequently seen in the CIAL group as opposed to the no leak group (p = 0.04). There was no intestinal contrast leakage in this cohort. Free air was present up to 9 days and loculated air up to 26 days without CIAL. Conclusion: Most postoperative CT features overlap between patients with and without CIAL. The only feature seen statistically more frequently with CIAL is peri-anastomotic loculated fluid containing air.

  16. Single-Shell Tank Leak Integrity Summary

    Energy Technology Data Exchange (ETDEWEB)

    Harlow, D. G. [Washington River Protection Solutions LLC, Richland, WA (United States); Girardot, C. L. [Washington River Protection Solutions LLC, Richland, WA (United States); Venetz, T. J. [Washington River Protection Solutions LLC, Richland, WA (United States)

    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).

  17. A reduced volumetric expansion factor plot

    Science.gov (United States)

    Hendricks, R. C.

    1979-01-01

    A reduced volumetric expansion factor plot has been constructed for simple fluids which is suitable for engineering computations in heat transfer. Volumetric expansion factors have been found useful in correlating heat transfer data over a wide range of operating conditions including liquids, gases and the near critical region.

  18. Performances of the leak microstructures

    CERN Document Server

    Lombardi, M; Lombardi, F S

    2002-01-01

    The capabilities of a new microstructure, anode point based, for the detection of gas ionizing radiations are stressed. For every single detected ionizing radiation it gives a pair of 'induced' charges (anodic and cathodic) of the same amount (pulses of the same amplitudes), of opposite sign, with the same collection time and essentially in time coincidence, that are proportional to the primary ionization collected. The complete lack of insulating materials in the active volume of this microstructure avoids problems of charging-up and makes stable and repeatable its behaviour. Primary avalanches with a size of more than 2.5x10 sup 7 electrons (4 pC) giving current pulses with a peak of more than 0.26 mA on 100 OMEGA and about 30 ns duration are possible with 5.9 keV X-rays of sup 5 sup 5 Fe working in proportional region and in isobutane gas. Single electrons emitted by a heated filament (E sub c <1 eV) were detected in 760 Torr of isobutane; with an estimated gas gain of 1.2x10 sup 6 a counting rate up to...

  19. Endoscopic diagnosis and treatment of biliar y leak in patients following liver transplantation:a prospective clinical study

    Institute of Scientific and Technical Information of China (English)

    Jia-Zhi Liao; Qiu Zhao; Hua Qin; Rong-Xiang Li; Wei Hou; Pei-Yuan Li; Nan-Zhi Liu; De-Ming Li

    2007-01-01

    BACKGROUND:Orthotopic liver transplantation has been widely used in patients with end-stage liver disease within the last two decades. However, the prevalence of biliary complications after liver transplantation remains high. The most common short-term biliary complication may be biliary leak. So, we examined 13 patients with biliary leak after liver transplantation, attempting to evaluate the role of endoscopic diagnosis and treatment of biliary leak and the incidence of bile duct stricture after healing of the leak. METHODS: Six cases of T-tube leak and seven cases of anastomosis leak complicating liver transplantation were enrolled in this prospective study. Six patients were treated by endoscopic plastic stent placement, two by nasobiliary catheter drainage, two by papillosphincterotomy, and three by nasobiliary catheter drainage combined with plastic stent placement. Some patients received growth hormone treatment. RESULTS: The bile leak resolution time was 10-35 days in 10 patients with complete documentation. The median time of leak resolution was 15.3 days. Four cases of anastomosis stricture, three cases of common hepatic duct and one case of multiple bile duct stenosis were detected by follow-up nasobiliary catheter cholangiography or endoscopic retrograde cholangiopancreatography. CONCLUSIONS:Endoscopic nasobiliary catheter or plastic stent placement is a safe and effective treatment for bile duct stricture occurring after bile leak resolution in most liver transplantation patients. Nasobiliary catheter combined with plastic stent placement may be the best choice for treating bile leak, because, theoretically, it may prevent the serious condition resulting from accidental nasobiliary catheter dislocation, and it may have prophylactic effects on upcoming bile duct stricture, although this should be further conifrmed.

  20. Modeling leaks from liquid hydrogen storage systems.

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Optical-Fiber Leak Detector

    Science.gov (United States)

    Workman, Gary L.; Kosten, Susan E.

    1994-01-01

    Proposed optical-fiber sensor detects small changes in pressure in elastomeric O-ring or similar pressure seal, which may indicate deterioration of seal and interpreted as indications of incipient failure. According to concept, length of optical fiber embedded in seal. Light-emitting diode illuminates one end of fiber; photodetector measures intensity of light emerging from other end. Pressure-induced changes in seal bend fiber slightly, altering microbending-induced loss of light from fiber and alter intensity of light at photodetector. Change in intensity approximately proportional to change in pressure.

  2. Experiences with leak rate calculations methods for LBB application

    Energy Technology Data Exchange (ETDEWEB)

    Grebner, H.; Kastner, W.; Hoefler, A.; Maussner, G. [and others

    1997-04-01

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

  3. 49 CFR 230.64 - Leaks under lagging.

    Science.gov (United States)

    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 service at once any boiler that has developed a leak under the lagging due to a crack in the shell, or...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Effect of heat leaks in platinum resistance thermometry.

    Science.gov (United States)

    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.

  6. Volumetric characterization of delamination fields via angle longitudinal wave ultrasound

    Science.gov (United States)

    Wertz, John; Wallentine, Sarah; Welter, John; Dierken, Josiah; Aldrin, John

    2017-02-01

    The volumetric characterization of delaminations necessarily precedes rigorous composite damage progression modeling. Yet, inspection of composite structures for subsurface damage remains largely focused on detection, resulting in a capability gap. In response to this need, angle longitudinal wave ultrasound was employed to characterize a composite surrogate containing a simulated three-dimensional delamination field with distinct regions of occluded features (shadow regions). Simple analytical models of the specimen were developed to guide subsequent experimentation through identification of optimal scanning parameters. The ensuing experiments provided visual evidence of the complete delamination field, including indications of features within the shadow regions. The results of this study demonstrate proof-of-principle for the use of angle longitudinal wave ultrasonic inspection for volumetric characterization of three-dimensional delamination fields. Furthermore, the techniques developed herein form the foundation of succeeding efforts to characterize impact delaminations within inhomogeneous laminar materials such as polymer matrix composites.

  7. COMPARISON OF VOLUMETRIC REGISTRATION ALGORITHMS FOR TENSOR-BASED MORPHOMETRY

    Science.gov (United States)

    Villalon, Julio; Joshi, Anand A.; Toga, Arthur W.; Thompson, Paul M.

    2015-01-01

    Nonlinear registration of brain MRI scans is often used to quantify morphological differences associated with disease or genetic factors. Recently, surface-guided fully 3D volumetric registrations have been developed that combine intensity-guided volume registrations with cortical surface constraints. In this paper, we compare one such algorithm to two popular high-dimensional volumetric registration methods: large-deformation viscous fluid registration, formulated in a Riemannian framework, and the diffeomorphic “Demons” algorithm. We performed an objective morphometric comparison, by using a large MRI dataset from 340 young adult twin subjects to examine 3D patterns of correlations in anatomical volumes. Surface-constrained volume registration gave greater effect sizes for detecting morphometric associations near the cortex, while the other two approaches gave greater effects sizes subcortically. These findings suggest novel ways to combine the advantages of multiple methods in the future. PMID:26925198

  8. Surfactant enhanced volumetric sweep efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Harwell, J.H.; Scamehorn, J.F.

    1989-10-01

    Surfactant-enhanced waterflooding is a novel EOR method aimed to improve the volumetric sweep efficiencies in reservoirs. The technique depends upon the ability to induce phase changes in surfactant solutions by mixing with surfactants of opposite charge or with salts of appropriate type. One surfactant or salt solution is injected into the reservoir. It is followed later by injection of another surfactant or salt solution. The sequence of injections is arranged so that the two solutions do not mix until they are into the permeable regions well away from the well bore. When they mix at this point, by design they form a precipitate or gel-like coacervate phase, plugging this permeable region, forcing flow through less permeable regions of the reservoir, improving sweep efficiency. The selectivity of the plugging process is demonstrated by achieving permeability reductions in the high permeable regions of Berea sandstone cores. Strategies were set to obtain a better control over the plug placement and the stability of plugs. A numerical simulator has been developed to investigate the potential increases in oil production of model systems. Furthermore, the hardness tolerance of anionic surfactant solutions is shown to be enhanced by addition of monovalent electrolyte or nonionic surfactants. 34 refs., 32 figs., 8 tabs.

  9. Advanced leak location-research evaluation demonstration (ALL-RED) project

    Science.gov (United States)

    Hammaker, Robert G.; Colsher, Richard J.

    1994-03-01

    The ALL-RED Project was developed to evaluate the use of IR thermography in three specific new areas: condenser air-in leakage; condenser tube leaks; and boiler casing leaks. These areas have plagued the utility industry by causing unscheduled downtime, increasing maintenance costs, and creating performance difficulties. Developing techniques that include: establishing specific methods of detection for each application; preparing guidelines for a program structure, technical approach, and cost benefit; as well as organizing a training program, will further enhance the use of this versatile technology and help utilities reduce down time and maintenance costs through condition monitoring using advanced IR Thermography techniques.

  10. Mass Spectrometric Calibration of Controlled Fluoroform Leak Rate Devices Technique and Uncertainty Analysis

    CERN Document Server

    Balsley, S D; Laduca, C A

    2003-01-01

    Controlled leak rate devices of fluoroform on the order of 10 sup - sup 8 atm centre dot cc sec sup - sup 1 at 25 C are used to calibrate QC-1 War Reserve neutron tube exhaust stations for leak detection sensitivity. Close-out calibration of these tritium-contaminated devices is provided by the Gas Dynamics and Mass Spectrometry Laboratory, Organization 14406, which is a tritium analytical facility. The mass spectrometric technique used for the measurement is discussed, as is the first principals calculation (pressure, volume, temperature and time). The uncertainty of the measurement is largely driven by contributing factors in the determination of P, V and T. The expanded uncertainty of the leak rate measurement is shown to be 4.42%, with a coverage factor of 3 (k=3).

  11. Predicting Package Defects: Quantification of Critical Leak Size

    OpenAIRE

    Gibney IV, Matthew Joseph

    2000-01-01

    Threshold leak sizes and leak rates were calculated for a number of liquid food products exhibiting a wide range of surface tension and viscosity values. From this data, one can see that mathematically, under typical pressure differentials generated in food packages (less than or equal to ±34.5 kPa), a leak will never start through a 2 μm defect. The calculated leak rates were compared to calculated evaporation rates. The evaporation rate exceeds the leak rate at lower sized microholes (...

  12. Laser Based 3D Volumetric Display System

    Science.gov (United States)

    1993-03-01

    Literature, Costa Mesa, CA July 1983. 3. "A Real Time Autostereoscopic Multiplanar 3D Display System", Rodney Don Williams, Felix Garcia, Jr., Texas...8217 .- NUMBERS LASER BASED 3D VOLUMETRIC DISPLAY SYSTEM PR: CD13 0. AUTHOR(S) PE: N/AWIU: DN303151 P. Soltan, J. Trias, W. Robinson, W. Dahlke 7...laser generated 3D volumetric images on a rotating double helix, (where the 3D displays are computer controlled for group viewing with the naked eye

  13. Scintigraphy for Pulmonary Capillary Protein Leak

    Science.gov (United States)

    1982-09-01

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

  14. Review of prospects and challenges of eye tracking in volumetric imaging.

    Science.gov (United States)

    Venjakob, Antje C; Mello-Thoms, Claudia R

    2016-01-01

    While eye tracking research in conventional radiography has flourished over the past decades, the number of eye tracking studies that looked at multislice images lags behind. A possible reason for the lack of studies in this area might be that the eye tracking methodology used in the context of conventional radiography cannot be applied one-on-one to volumetric imaging material. Challenges associated with eye tracking in volumetric imaging are particularly associated with the selection of stimulus material, the detection of events in the eye tracking data, the calculation of meaningful eye tracking parameters, and the reporting of abnormalities. However, all of these challenges can be addressed in the design of the experiment. If this is done, eye tracking studies using volumetric imaging material offer almost unlimited opportunity for perception research and are highly relevant as the number of volumetric images that are acquired and interpreted is rising.

  15. Epidural block and neostigmine cause anastomosis leak

    Directory of Open Access Journals (Sweden)

    Ataro G

    2016-05-01

    Full Text Available Getu Ataro Department of Anesthesia, Jimma University, Jimma, EthiopiaI read the article by Phillips entitled, “Reducing gastrointestinal anastomotic leak rates: review of challenges and solutions”, published in the journal of Open Access Surgery with enthusiasm and found it crucial for perioperative management of patients with gastrointestinal (GI surgery, particularly anastomosis. I appreciate the author’s exhaustive search of literature and discussion with some limitation on review basics like methodology, which may affect the reliability of the review findings. The effects of risk factors for anastomosis leak, such as malnutrition, smoking, steroid use, bowel preparation, chemotherapy, duration of surgery, use of pressors, intravenous fluid administration, blood transfusion, and surgical anastomotic technique, were well discussed.1 However, from anesthesia perspective, there are some other well-studied risk factors that can affect healing of anastomosis wound and cause anastomosis leak. Among others, the effect of neostigmine and epidural block has been reported in many studies since half a century ago. View the original paper by Phillips

  16. Regulated tailored suction vs regulated seal: a prospective randomized trial on air leak duration.

    Science.gov (United States)

    Brunelli, Alessandro; Salati, Michele; Pompili, Cecilia; Refai, Majed; Sabbatini, Armando

    2013-05-01

    The objective of this study was to compare the air leak duration of two regulated chest tube modes following pulmonary lobectomy. This is a prospective randomized trial on 100 consecutive pulmonary lobectomies (2010-11) performed for lung cancer. A single 24-French chest tube was connected to an electronic system capable of maintaining the pleural pressure within preset values (regulated suction mode) or within a physiological range (regulated seal mode). Patients were randomized to two groups: Group 1, regulated individualized suction (range: -11 to -20 cmH2O, according to lobectomy type); Group 2, regulated seal (-2 cmH2O). The main endpoint was the duration of air leak (h) calculated from the end of the operation to a value consistently below 20 ml/min. Patients with prolonged air leak (>168 h) were connected to a portable device before discharge. Their air leak duration was considered as 192 h. The sample size was calculated to detect 1-day difference in air leak duration with a statistical power of 80%. The two groups were well matched for several baseline and surgical characteristics. No crossovers occurred between groups. The average air leak duration (Group 1: 28 vs Group 2: 22.2, P = 0.6), and the number of patients with prolonged air leak (Group 1: 5 vs Group 2: 4, P = 0.7) and with other complications (Group 1: 6 patients vs Group 2: 7 patients, P = 0.9) were similar between the groups. Sixteen patients of Group 1 and 21 of Group 2 had an air leak present immediately after extubation. Among them, patients of Group 2 (regulated seal) had an air leak lasting 34.5 h less than those of Group 1 (regulated suction) (52.9 vs 87.4, P = 0.07). Regulated seal is as effective and safe as regulated suction in managing chest tubes following lobectomy. This information demonstrates with objective data the non-superiority of regulated suction vs regulated seal and may assist in future investigations on regulated pleural pressure.

  17. The experiment and analysis on small leak phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Kyung Chai; Hwang, S. T.; Kim, B. H.; Jeong, J. Y

    2000-07-01

    The liquid sodium which is used as a coolant in LMFBR, may give rise to a serious trouble in the safety aspect of steam generator. The defects in a heat transfer tube, such as pin-hole or tube welding defect, will result in a leakage of high pressure steam into the sodium side and production of hydrogen gas and corrosive sodium compounds which can cause significant damage to the tube wall of steam generator by using exothermic reaction. In significant damage to the tube wall of steam generator by using exothermic reaction. In this case, initial leak size will be enlarged with time and the leak rate developed to large leak through the micro, small, intermediate leaks. Therefore, the analysis of sodium-water reaction phenomena on the micro and small water leaks in the heat transfer tube is very important in the initial leak stage in the aspects of the protection of leak progress and safety evaluation of steam generator. In this study, firstly, the micro and small leaks phenomena, such as reopen size, shape, and time of leak path, self-wastage, corrosion of tube materials, was analyzed from the literature survey and water leakage experiments using the leak specimen. In small water leak experiments, the leak path was plugged by the sodium-water reaction products at the leak path of a specimen, and re-open phenomena were not observed in initial experiments. Other leak experiments, reopen phenomena of self-plugged leak path was observed. Re-open mechanism of sealed path could be explained by the thermal transient and vibration of heat transfer tube. As a result, perfect reopen time of self plugged leak path was observed to be about 130 minutes after water leak initiation. Reopen shape of a specimen was appeared with double layer of circular type, and reopen size of this specimen surface was about 2 mm diameter on sodium side. Also, the corrosion of a specimen initiated from sodium side, the segregation phenomena of Cr in the specimen was found much more than those of

  18. Vapor Leak Sensor Using Polarization Property and Stereoscopic Measurement for Plant Inspection

    Science.gov (United States)

    Nakashima, Toshiro; Nakajima, Hajime; Matoba, Osamu

    This paper reports a sensor for the plant inspections to detect leaking vapor. Plants are usually inspected by patrolling inspectors. It requires high level skills to selectively detect abnormal phenomena occurring in various types of equipment under the complicated environments. In this research, we developed a remote detecting sensor for the vapor leaking from piping, which is one of the priority control items inside plants. The basic principle of the sensor is specifically to sense the scattered light when laser beam is illuminated on the vapor. It is also discovered in our basic experiments that there is big difference in the polarization property between the light scattered by vapor and surface structures inside plants. The sensor can discriminate the light scattered by vapor from other types of scattered light utilizing the difference of the polarization property, then detecting the light scattered by vapor only. A prototype model is fabricated for substantiating the basic property of leaking vapor detection. As a result, it is confirmed that the prototype model not only has sufficient detecting capability, but can selectively detect vapor only. In conclusion, it is confirmed that the developed sensor satisfies the requirements for the plant inspection sensors, and has sufficient capability for practical usage.

  19. Design of an Infrared Imaging System for Robotic Inspection of Gas Leaks in Industrial Environments

    Directory of Open Access Journals (Sweden)

    Ramon Barber

    2015-03-01

    Full Text Available Gas detection can become a critical task in dangerous environments that involve hazardous or contaminant gases, and the use of imaging sensors provides an important tool for leakage location. This paper presents a new design for remote sensing of gas leaks based on infrared (IR imaging techniques. The inspection system uses an uncooled microbolometer detector, operating over a wide spectral bandwidth, that features both low size and low power consumption. This equipment is boarded on a robotic platform, so that wide objects or areas can be scanned. The detection principle is based on the use of active imaging techniques, where the use of external IR illumination enhances the detection limit and allows the proposed system to operate in most cases independently from environmental conditions, unlike passive commercial approaches. To illustrate this concept, a fully radiometric description of the detection problem has been developed; CO2 detection has been demonstrated; and simulations of typical gas detection scenarios have been performed, showing that typical industrial leaks of CH4 are well within the detection limits. The mobile platform where the gas sensing system is going to be implemented is a robot called TurtleBot. The control of the mobile base and of the inspection device is integrated in ROS architecture. The exploration system is based on the technique of Simultaneous Localization and Mapping (SLAM that makes it possible to locate the gas leak in the map.

  20. Prioritizing Test Cases for Memory Leaks in Android Applications

    Institute of Scientific and Technical Information of China (English)

    Ju Qian; Di Zhou

    2016-01-01

    Mobile applications usually can only access limited amount of memory. Improper use of the memory can cause memory leaks, which may lead to performance slowdowns or even cause applications to be unexpectedly killed. Although a large body of research has been devoted into the memory leak diagnosing techniques after leaks have been discovered, it is still challenging to find out the memory leak phenomena at first. Testing is the most widely used technique for failure discovery. However, traditional testing techniques are not directed for the discovery of memory leaks. They may spend lots of time on testing unlikely leaking executions and therefore can be inefficient. To address the problem, we propose a novel approach to prioritize test cases according to their likelihood to cause memory leaks in a given test suite. It firstly builds a prediction model to determine whether each test can potentially lead to memory leaks based on machine learning on selected code features. Then, for each input test case, we partly run it to get its code features and predict its likelihood to cause leaks. The most suspicious test cases will be suggested to run at first in order to reveal memory leak faults as soon as possible. Experimental evaluation on several Android applications shows that our approach is effective.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Volumetric measurements of pulmonary nodules: variability in automated analysis tools

    Science.gov (United States)

    Juluru, Krishna; Kim, Woojin; Boonn, William; King, Tara; Siddiqui, Khan; Siegel, Eliot

    2007-03-01

    Over the past decade, several computerized tools have been developed for detection of lung nodules and for providing volumetric analysis. Incidentally detected lung nodules have traditionally been followed over time by measurements of their axial dimensions on CT scans to ensure stability or document progression. A recently published article by the Fleischner Society offers guidelines on the management of incidentally detected nodules based on size criteria. For this reason, differences in measurements obtained by automated tools from various vendors may have significant implications on management, yet the degree of variability in these measurements is not well understood. The goal of this study is to quantify the differences in nodule maximum diameter and volume among different automated analysis software. Using a dataset of lung scans obtained with both "ultra-low" and conventional doses, we identified a subset of nodules in each of five size-based categories. Using automated analysis tools provided by three different vendors, we obtained size and volumetric measurements on these nodules, and compared these data using descriptive as well as ANOVA and t-test analysis. Results showed significant differences in nodule maximum diameter measurements among the various automated lung nodule analysis tools but no significant differences in nodule volume measurements. These data suggest that when using automated commercial software, volume measurements may be a more reliable marker of tumor progression than maximum diameter. The data also suggest that volumetric nodule measurements may be relatively reproducible among various commercial workstations, in contrast to the variability documented when performing human mark-ups, as is seen in the LIDC (lung imaging database consortium) study.

  3. CHINA'S WORST OIL LEAK CLEARED EXPENSIVELY

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Eight days and nights of clean-up efforts after the worst oil leak ever in Chinese waters, the aftermath of a collision between two foreign ships happening at 9:35 pm on December 7 about 8 nautical miles away from the mouth of the Pearl River and near the Danjiang Island, have finally paid off. So far, hundreds of tons of waste oil and polluted water have been cleared up. A large area of oil spills has been cleaned thanks to the prompt and proper operation launched just two hours after the accident.

  4. The pump and leak steady-state concept with a variety of regulated leak pathways

    DEFF Research Database (Denmark)

    Hoffmann, E K

    2001-01-01

    found that the passive ion leaks play an active role in cell volume control. (iii) The use of isotopes and Ussing's famous flux ratio equation provided an ingenious instrument for distinguishing the various transport routes. We used this to identify the Na,K,2Cl cotransport system as accounting...

  5. Develop Efficient Leak Proof M1 Abrams Plenum Seal

    Science.gov (United States)

    2014-05-07

    UNCLASSIFIED UNCLASSIFIED ER-GLSV11389-001.docx Develop Efficient Leak Proof M1 Abrams Plenum Seal SBIR Phase I: Topic A13-061...Leak Proof M1 Abrams Plenum Seal Christian Muehfeld Steve Pennala Great Lakes Sound & Vibration, Inc. 47140 North Main Street Houghton, MI 49931 ER...061. The purpose of this report is to show the feasibility of developing an efficient, leak proof plenum seal for the M1 Abrams . It also shows the

  6. Nonequilibrium volumetric response of shocked polymers

    Energy Technology Data Exchange (ETDEWEB)

    Clements, B E [Los Alamos National Laboratory

    2009-01-01

    Polymers are well known for their non-equilibrium deviatoric behavior. However, investigations involving both high rate shock experiments and equilibrium measured thermodynamic quantities remind us that the volumetric behavior also exhibits a non-equilibrium response. Experiments supporting the notion of a non-equilibrium volumetric behavior will be summarized. Following that discussion, a continuum-level theory is proposed that will account for both the equilibrium and non-equilibrium response. Upon finding agreement with experiment, the theory is used to study the relaxation of a shocked polymer back towards its shocked equilibrium state.

  7. Seeding optimization for instantaneous volumetric velocimetry. Application to a jet in crossflow

    CERN Document Server

    Cambonie, Tristan

    2014-01-01

    Every volumetric velocimetry measurements based on tracer (particles, bubbles, etc.) detection can be strongly influenced by the optical screening phenomenon. It has to be taken into account when the the statistical properties associated to the performances of the particle detection and tracking algorithms are significantly affected. It leads to a maximum concentration of particles in the images thus limiting the final spatial resolution of the instantaneous three-dimensional three-components (3D3C) velocity fields. A volumetric velocimetry system based on Defocused Digital Particle Image Velocimetry is used to show that above a critical visual concentration of particles in the images, the concentration and accuracy of the final instantaneous raw velocity vector field drop. The critical concentration depends on physical parameters as well as on the processing algorithms. Three distinct regimes are identified. In the first regime, the concentration is well adapted to volumetric velocimetry, the largest concent...

  8. Quantifying Urban Natural Gas Leaks from Street-level Methane Mapping: Measurements and Uncertainty

    Science.gov (United States)

    von Fischer, J. C.; Ham, J. M.; Griebenow, C.; Schumacher, R. S.; Salo, J.

    2013-12-01

    Leaks from the natural gas pipeline system are a significant source of anthropogenic methane in urban settings. Detecting and repairing these leaks will reduce the energy and carbon footprints of our cities. Gas leaks can be detected from spikes in street-level methane concentrations measured by analyzers deployed on vehicles. While a spike in methane concentration indicates a leak, an algorithm (e.g., inverse model) must be used to estimate the size of the leak (i.e., flux) from concentration data and supporting meteorological information. Unfortunately, this drive-by approach to leak quantification is confounded by the complexity of urban roughness, changing weather conditions, and other incidental factors (e.g., traffic, vehicle speed, etc.). Furthermore, the vehicle might only pass through the plume one to three times during routine mapping. The objective of this study was to conduct controlled release experiments to better quantify the relationship between mobile methane concentration measurements and the size and location of the emission source (e.g., pipeline leakage) in an urban environment. A portable system was developed that could release methane at known rates between 10 and 40 LPM while maintaining concentrations below the lower explosive limit. A mapping vehicle was configured with fast response methane analyzers, GPS, and meteorological instruments. Portable air-sampling tripods were fabricated that could be deployed at defined distances downwind from the release point and automatically-triggered to collect grab samples. The experimental protocol was as follows: (1) identify an appropriate release point within a city, (2) release methane at a known rate, (3) measure downwind street-level concentrations with the vehicle by making multiple passes through the plume, and (4) collect supporting concentration and meteorological data with the static tripod samplers deployed in the plume. Controlled release studies were performed at multiple locations and

  9. Process conditions and volumetric composition in composites

    DEFF Research Database (Denmark)

    Madsen, Bo

    2013-01-01

    The obtainable volumetric composition in composites is linked to the gravimetric composition, and it is influenced by the conditions of the manufacturing process. A model for the volumetric composition is presented, where the volume fractions of fibers, matrix and porosity are calculated as a fun...... is increased. Altogether, the model is demonstrated to be a valuable tool for a quantitative analysis of the effect of process conditions. Based on the presented findings and considerations, examples of future work are mentioned for the further improvement of the model.......The obtainable volumetric composition in composites is linked to the gravimetric composition, and it is influenced by the conditions of the manufacturing process. A model for the volumetric composition is presented, where the volume fractions of fibers, matrix and porosity are calculated...... as a function of the fiber weight fraction, and where parameters are included for the composite microstructure, and the fiber assembly compaction behavior. Based on experimental data of composites manufactured with different process conditions, together with model predictions, different types of process related...

  10. Indexing Volumetric Shapes with Matching and Packing.

    Science.gov (United States)

    Koes, David Ryan; Camacho, Carlos J

    2015-04-01

    We describe a novel algorithm for bulk-loading an index with high-dimensional data and apply it to the problem of volumetric shape matching. Our matching and packing algorithm is a general approach for packing data according to a similarity metric. First an approximate k-nearest neighbor graph is constructed using vantage-point initialization, an improvement to previous work that decreases construction time while improving the quality of approximation. Then graph matching is iteratively performed to pack related items closely together. The end result is a dense index with good performance. We define a new query specification for shape matching that uses minimum and maximum shape constraints to explicitly specify the spatial requirements of the desired shape. This specification provides a natural language for performing volumetric shape matching and is readily supported by the geometry-based similarity search (GSS) tree, an indexing structure that maintains explicit representations of volumetric shape. We describe our implementation of a GSS tree for volumetric shape matching and provide a comprehensive evaluation of parameter sensitivity, performance, and scalability. Compared to previous bulk-loading algorithms, we find that matching and packing can construct a GSS-tree index in the same amount of time that is denser, flatter, and better performing, with an observed average performance improvement of 2X.

  11. Confidence leak in perceptual decision-making

    Science.gov (United States)

    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

  12. 40 CFR 1065.644 - Vacuum-decay leak rate.

    Science.gov (United States)

    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...

  13. Unexpected triggering of the dialysate blood leak detector by haemolysis.

    Science.gov (United States)

    Lindley, E; Finney, D; Jones, P; Lewington, A; O'Reagan, A; Webb, G

    2015-06-01

    This case showed that it is possible for haemoglobin released by haemolysis in the extracorporeal circuit to pass through a high permeability (albumin retaining) dialyser membrane. In the incident described, the blood leak detector of the dialysis machine was activated before the patient became symptomatic. Haemolysis should be considered as a possible cause of blood leak alarms during dialysis with high flux membranes.

  14. Leaks in gas mains - Location using GIS and GPS; Leckstellen in Gasrohrnetzen. Aufspueren mit Unterstuetzung durch GIS und GPS

    Energy Technology Data Exchange (ETDEWEB)

    Huber, D.

    2009-07-01

    This article takes a look how leaks in gas mains can be located with the help of geographical information systems (GIS) and the satellite-based Global Positioning System (GPS). The advantages for long-term planning and, in future, maintenance work are stressed. Experienced gained by the IWB utility in Basel, Switzerland, is discussed. Here, a system for the monitoring and maintenance of the whole of the City of Basel's natural gas supply network is discussed. Cost savings and a particularly improved increase in the quality of leak detection work is noted. Modern technology using GPS-based equipment in the detection of leaks in the gas mains is reviewed. An example of the documentation of the gas mains in a GIS system is given.

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

    Science.gov (United States)

    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.

  16. Automatic recovery from resource exhaustion exceptions by collecting leaked resources

    Institute of Scientific and Technical Information of China (English)

    Zi-ying DAI; Xiao-guang MAO; Li-qian CHEN; Yan LEI

    2014-01-01

    Despite the availability of garbage collectors, programmers must manually manage non-memory fi nite system resources such as fi le descriptors. Resource leaks can gradually consume all available resources and cause programs to raise resource exhaustion exceptions. However, programmers commonly provide no effective recovery approach for resource exhaustion exceptions, which often causes programs to halt without completing their tasks. In this paper, we propose to automatically recover programs from resource exhaustion exceptions caused by resource leaks. We transform programs to catch resource exhaustion exceptions, collect leaked resources, and then retry the failure code. A resource collector is designed to identify leaked resources and safely release them. We implement our approach for Java programs. Experimental results show that our approach can successfully handle resource exhaustion exceptions caused by reported resource leaks and allow programs to complete their tasks with an average execution time increase of 2.52%and negligible bytecode size increase.

  17. Fatal Primary Capillary Leak Syndrome in a Late Preterm Newborn.

    Science.gov (United States)

    Kulihova, Katarina; Prochazkova, Martina; Semberova, Jana; Janota, Jan

    2016-10-01

    Primary capillary leak syndrome is a rare disease of unknown etiology, characterized by episodes of vascular collapse and plasma extravasation, which may lead to multiple organ failure. Primary capillary leak is extremely rare in children. The authors report a case of a late preterm newborn with fatal capillary leak syndrome of unknown etiology, manifesting as hypotension unresponsive to treatment, extravasation leading to generalised edema, disseminated intravascular coagulation and finally, multiple organ dysfunction syndrome. Aggressive volumotherapy and a combination of inotropes and high doses of terlipressin did not influence systemic vascular collapse and plasma extravasation. The newborn developed multiple organ failure and died on day 27 of life. Investigations performed failed to reveal any specific cause of capillary leak. This is the first report of a fatal primary capillary leak syndrome in a newborn.

  18. A Novel Feature Extraction Method for Monitoring (Vehicular) Fuel Storage System Leaks

    Science.gov (United States)

    2014-10-02

    optimization) based learning methods. Leak detection mechanism as part of an overall emission control strategy is gaining importance in recent...fundamentally different way of extracting information from the in-tank pressure signal stream as it is one of most critical parts of an overall redesign...signal procesing methods such as signal smoothing, clipping and flipping. Other common modifications may also include multiple scalers associated with

  19. The Application of Data Acquisition Control Technology in Flammable Refrigerant Leak Detection Alarm System Based on RS-485 Bus%基于RS-485总线的数据采集控制技术在可燃性制冷剂泄露检测警报系统中的应用

    Institute of Scientific and Technical Information of China (English)

    郭军

    2014-01-01

    本文主要介绍泓格RS-485网络在工业控制中的优势以及基于RS-485总线的数据采集系统的特点及应用案例分析。泓格基于RS-485总线的远程数据采集控制系统方案丰富多彩,提供用户以广泛的选择。新型环保制冷剂多是可燃性天然物质,在期产业化应用中存在易燃易爆的危险性,本文以案例形式介绍了使用RS-485总线的数据采集控制技术在可燃性制冷剂泄露检测警报系统中的技术应用。%This paper mainly introduces the advantage of case RS-485 network of ICP DAS in industrial control, and the characteristics of data acquisition system and application case analysis based on RS-485 bus. Based on RS-485 bus, ICP DAS’s remote data acquisition control system schemes is plentiful. It provides the users with wide selection. Most of the new environment-friendly refrigerants are flammability natural-occurring substance. Thus, it has the dangerousness of flammable and combustible in the period of industrialization application. Combined with the cases, this paper introduces the application of data acquisition control technology in flammable refrigerant leak detection alarm system based on RS-485 bus.

  20. Leak testing of cryogenic components - problems and solutions

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, S P; Pandarkar, S P; Unni, T G; Sinha, A K; Mahajan, K; Suthar, R L [Centre for Design and Manufacture, Bhabha Atomic Research Centre, Mumbai 400085 (India)], E-mail: sushils@barc.gov.in

    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 (LN{sub 2}) being circulated through an annular cavity machined on the walls of the pot. Transfer lines for LN{sub 2} 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 LN{sub 2} 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

  1. Leak testing of cryogenic components — problems and solutions

    Science.gov (United States)

    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

  2. NDE Technology Development Program for Non-Visual Volumetric Inspection Technology; Sensor Effectiveness Testing Report

    Energy Technology Data Exchange (ETDEWEB)

    Moran, Traci L.; Larche, Michael R.; Denslow, Kayte M.; Glass, Samuel W.

    2017-08-31

    The Pacific Northwest National Laboratory (PNNL) located in Richland, Washington, hosted and administered Sensor Effectiveness Testing that allowed four different participants to demonstrate the NDE volumetric inspection technologies that were previously demonstrated during the Technology Screening session. This document provides a Sensor Effectiveness Testing report for the final part of Phase I of a three-phase NDE Technology Development Program designed to identify and mature a system or set of non-visual volumetric NDE technologies for Hanford DST primary liner bottom inspection. Phase I of the program will baseline the performance of current or emerging non-visual volumetric NDE technologies for their ability to detect and characterize primary liner bottom flaws, and identify candidate technologies for adaptation and maturation for Phase II of the program.

  3. High temperature structure leak before break assessment guideline(draft)

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chang Gyu; Kim, Jong Bum; Lee, Hyeong Yeon; Joo, Young Sang; Lee, Jae Han

    2005-03-15

    This study describes the Leak Before Break(LBB) procedure applicable to the reactor structure of Liquid Metal Reactor(LMR) which is operated at a high temperature. The purpose of LBB in LMR is to assure the defence in depth safety. The technically advanced countris of LMR development, such as Japan, UK and France, have their own LBB evaluation code and their procedures were investigated thoroughly to prepare the draft edition of high temperature LBB assessment guideline for the high temperature LMR structures under development in Korea. The key issues are the defect initiation, the defect propagation and the fast rupture of structures under the fatigue loading or the creep-fatigue loading condition. Additionlly, the detectable defect length and crack opening evaluation for the leakage detection method are analyzed and included in this guideline. This study is to prepare the draft edition of LBB for a high temperature structure and the additional item including the parameter analysis will be supplemented in future. Also, the evaluation procedure will be applied to a LMR structure and result will be compared with the test results so that the LBB technology will be complemented continuously.

  4. Rapid Hydrogen and Methane Sensors for Wireless Leak Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Under NASA STTR NNK07EA39C, ASR&D developed passive surface acoustic wave (SAW) based hydrogen sensors that utilize Pd nanocluster films on self-assembled...

  5. Volumetric breast density affects performance of digital screening mammography.

    Science.gov (United States)

    Wanders, Johanna O P; Holland, Katharina; Veldhuis, Wouter B; Mann, Ritse M; Pijnappel, Ruud M; Peeters, Petra H M; van Gils, Carla H; Karssemeijer, Nico

    2017-02-01

    To determine to what extent automatically measured volumetric mammographic density influences screening performance when using digital mammography (DM). We collected a consecutive series of 111,898 DM examinations (2003-2011) from one screening unit of the Dutch biennial screening program (age 50-75 years). Volumetric mammographic density was automatically assessed using Volpara. We determined screening performance measures for four density categories comparable to the American College of Radiology (ACR) breast density categories. Of all the examinations, 21.6% were categorized as density category 1 ('almost entirely fatty') and 41.5, 28.9, and 8.0% as category 2-4 ('extremely dense'), respectively. We identified 667 screen-detected and 234 interval cancers. Interval cancer rates were 0.7, 1.9, 2.9, and 4.4‰ and false positive rates were 11.2, 15.1, 18.2, and 23.8‰ for categories 1-4, respectively (both p-trend density categories: 85.7, 77.6, 69.5, and 61.0% for categories 1-4, respectively (p-trend density, automatically measured on digital mammograms, impacts screening performance measures along the same patterns as established with ACR breast density categories. Since measuring breast density fully automatically has much higher reproducibility than visual assessment, this automatic method could help with implementing density-based supplemental screening.

  6. Combined surface and volumetric occlusion shading

    KAUST Repository

    Schott, Matthias O.

    2012-02-01

    In this paper, a method for interactive direct volume rendering is proposed that computes ambient occlusion effects for visualizations that combine both volumetric and geometric primitives, specifically tube shaped geometric objects representing streamlines, magnetic field lines or DTI fiber tracts. The proposed algorithm extends the recently proposed Directional Occlusion Shading model to allow the rendering of those geometric shapes in combination with a context providing 3D volume, considering mutual occlusion between structures represented by a volume or geometry. © 2012 IEEE.

  7. Impact of Pancreatic Leaks on Survival Following Pancreaticoduodenectomy

    Directory of Open Access Journals (Sweden)

    Fabio Ausania

    2010-05-01

    Full Text Available Context Pancreatic leak following pancreaticoduodenectomy has a major impact on postoperative mortality. However, it is not clear whether pancreatic leaks affect long term survival in patients with pancreatic ductal adenocarcinoma. Objective The aim of this study is to compare the long term outcome in patients who underwent pancreaticoduodenectomy, with and without postoperative pancreatic leak. Patients All 133 patients who underwent a pancreaticoduodenectomy at the HepatoPancreatoBiliary Unit, Addenbrooke’s Hospital, Cambridge, between June 2002 and June 2007 were identified from a prospectively held database. The study was restricted to 47 patients who had a confirmed diagnosis of pancreatic ductal adenocarcinoma. Setting Pancreatic leak was defined as drain fluid amylase more than three times the serum level for more than 3 days post operatively. Main outcome measure Long term survival of patients with and without leaks were compared using Kaplan-Meier curves and significance was measured using the log-rank test. Results Median follow-up was 30.8 months. The median actuarial survival of all ductal adenocarcinoma patients was 19 months. Pancreatic leaks occurred in 9 patients (19.1%. There were no significant differences in the overall survival or presence of recurrence between the two groups. Conclusions Pancreatic leak following pancreaticoduodenectomy does not appear to impact on long-term outcome of patients with pancreatic ductal adenocarcinoma.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    Kay Hamacher

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  12. Leak Path Development in CO2 Wells

    Science.gov (United States)

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

    2014-12-01

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

  13. MR volumetric assessment of endolymphatic hydrops

    Energy Technology Data Exchange (ETDEWEB)

    Guerkov, R.; Berman, A.; Jerin, C.; Krause, E. [University of Munich, Department of Otorhinolaryngology Head and Neck Surgery, Grosshadern Medical Centre, Munich (Germany); University of Munich, German Centre for Vertigo and Balance Disorders, Grosshadern Medical Centre, Marchioninistr. 15, 81377, Munich (Germany); Dietrich, O.; Flatz, W.; Ertl-Wagner, B. [University of Munich, Institute of Clinical Radiology, Grosshadern Medical Centre, Munich (Germany); Keeser, D. [University of Munich, Institute of Clinical Radiology, Grosshadern Medical Centre, Munich (Germany); University of Munich, German Centre for Vertigo and Balance Disorders, Grosshadern Medical Centre, Marchioninistr. 15, 81377, Munich (Germany); University of Munich, Department of Psychiatry and Psychotherapy, Innenstadtkliniken Medical Centre, Munich (Germany)

    2014-10-16

    We aimed to volumetrically quantify endolymph and perilymph spaces of the inner ear in order to establish a methodological basis for further investigations into the pathophysiology and therapeutic monitoring of Meniere's disease. Sixteen patients (eight females, aged 38-71 years) with definite unilateral Meniere's disease were included in this study. Magnetic resonance (MR) cisternography with a T2-SPACE sequence was combined with a Real reconstruction inversion recovery (Real-IR) sequence for delineation of inner ear fluid spaces. Machine learning and automated local thresholding segmentation algorithms were applied for three-dimensional (3D) reconstruction and volumetric quantification of endolymphatic hydrops. Test-retest reliability was assessed by the intra-class coefficient; correlation of cochlear endolymph volume ratio with hearing function was assessed by the Pearson correlation coefficient. Endolymph volume ratios could be reliably measured in all patients, with a mean (range) value of 15 % (2-25) for the cochlea and 28 % (12-40) for the vestibulum. Test-retest reliability was excellent, with an intra-class coefficient of 0.99. Cochlear endolymphatic hydrops was significantly correlated with hearing loss (r = 0.747, p = 0.001). MR imaging after local contrast application and image processing, including machine learning and automated local thresholding, enable the volumetric quantification of endolymphatic hydrops. This allows for a quantitative assessment of the effect of therapeutic interventions on endolymphatic hydrops. (orig.)

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

    Science.gov (United States)

    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. Extraperitoneal urine leak after renal transplantation: the role of radionuclide imaging and the value of accompanying SPECT/CT - a case report

    Directory of Open Access Journals (Sweden)

    Kostakoglu Lale

    2010-10-01

    Full Text Available Abstract Background The differentiation of the nature of a fluid collection as a complication of kidney transplantation is important for management and treatment planning. Early and delayed radionuclide renography can play an important role in the evaluation of a urine leak. However, it is sometimes limited in the evaluation of the exact location and extent of a urine leak. Case Presentation A 71-year-old male who had sudden anuria, scrotal swelling and elevated creatinine level after cadaveric renal transplantation performed Tc-99 m MAG3 renography to evaluate the renal function, followed by an ultrasound which was unremarkable. An extensive urine leak was evident on the planar images. However, an exact location of the urine leak was unknown. Accompanying SPECT/CT images confirmed a urine leak extending from the lower aspect of the transplant kidney to the floor of the pelvic cavity, presacral region and the scrotum via right inguinal canal as well as to the right abdominal wall. Conclusions Renal scintigraphy is very useful to detect a urine leak after renal transplantation. However, planar imaging is sometimes limited in evaluating the anatomical location and extent of a urine leak accurately. In that case accompanying SPECT/CT images are very helpful and valuable to evaluate the anatomical relationships exactly.

  16. Is the 80% leak criterion always appropriate?

    Energy Technology Data Exchange (ETDEWEB)

    Haines, Harvey [Kiefner and Associates, Inc., Vienna, VA (United States); McNealy, Rick [Applus-RTD, Houston, TX (United States); Rosenfeld, M.J. [Kiefner and Associates, Inc., Worthington, OH (United States)

    2010-07-01

    For evaluating metal loss depth by corrosion, ASME B31G recommends 80% of the wall thickness as an upper limit. A pipeline can still be safe with deeper corrosion, but the main question is whether conservative criteria are necessary because of errors in corrosion depth measurement. Corrosion depths over 80% might be acceptable if the measurement error was well understood and if errors could be treated in a routine and practical manner. Measurement errors are well understood when published values exist for commercial ILI tools and errors can be reassessed during remediation using in-the-ditch measurements. In the case of low-pressure pipelines, the 80% recommendation seems to be overly conservative and restricts re-inspection intervals unnecessarily. Otherwise, 80% seems appropriate in view of the current ILI and manual pit gauge depth measurement technology, but if the accuracy of ILI inspections was improved, fewer immediate digs could be possible. Corrosion deeper than 80% seems to cause leaks by perforation rather than mechanical failure.

  17. Marginal Space Deep Learning: Efficient Architecture for Volumetric Image Parsing.

    Science.gov (United States)

    Ghesu, Florin C; Krubasik, Edward; Georgescu, Bogdan; Singh, Vivek; Yefeng Zheng; Hornegger, Joachim; Comaniciu, Dorin

    2016-05-01

    Robust and fast solutions for anatomical object detection and segmentation support the entire clinical workflow from diagnosis, patient stratification, therapy planning, intervention and follow-up. Current state-of-the-art techniques for parsing volumetric medical image data are typically based on machine learning methods that exploit large annotated image databases. Two main challenges need to be addressed, these are the efficiency in scanning high-dimensional parametric spaces and the need for representative image features which require significant efforts of manual engineering. We propose a pipeline for object detection and segmentation in the context of volumetric image parsing, solving a two-step learning problem: anatomical pose estimation and boundary delineation. For this task we introduce Marginal Space Deep Learning (MSDL), a novel framework exploiting both the strengths of efficient object parametrization in hierarchical marginal spaces and the automated feature design of Deep Learning (DL) network architectures. In the 3D context, the application of deep learning systems is limited by the very high complexity of the parametrization. More specifically 9 parameters are necessary to describe a restricted affine transformation in 3D, resulting in a prohibitive amount of billions of scanning hypotheses. The mechanism of marginal space learning provides excellent run-time performance by learning classifiers in clustered, high-probability regions in spaces of gradually increasing dimensionality. To further increase computational efficiency and robustness, in our system we learn sparse adaptive data sampling patterns that automatically capture the structure of the input. Given the object localization, we propose a DL-based active shape model to estimate the non-rigid object boundary. Experimental results are presented on the aortic valve in ultrasound using an extensive dataset of 2891 volumes from 869 patients, showing significant improvements of up to 45

  18. Sulphur hexafluoride gas detection

    CSIR Research Space (South Africa)

    Stolper, R

    2006-02-01

    Full Text Available This poster describes the development process of an electro-optical based solution for detecting and locating SF6 gas leaks at gas insulated switch gear. The principal technologies that were researched are explained with their advantages...

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

    Science.gov (United States)

    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.

  20. A multistage volumetric bar chart chip for visualized quantification of DNA

    OpenAIRE

    Song, Yujun; Wang, Yuanchen; Qin, Lidong

    2013-01-01

    Nucleic acid detection is critical in disease diagnosis as well as in the environmental assays of harmful bacteria or viruses and forensic applications. Current methods for visualized quantification of DNA require costly and sophisticated instruments. Here, we report a multistage propelled volumetric bar chart chip (MV-Chip) for multiplexing and quantitative detection of DNA. Owing to its ‘rocket-like’ propelling reaction, the pre-deposited platinum films could perform cascade amplification a...

  1. Leaking Underground Tanks in Rhode Island; LUSTs12

    Data.gov (United States)

    University of Rhode Island Geospatial Extension Program — This dataset shows the location of storage tanks and associated piping used for petroleum and certain hazardous substances that have experienced leaks as determined...

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

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  3. Numerical Simulation of Gas Leaking Diffusion from Storage Tank

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  5. Duodenal stump leak following a duodenal switch: A case report

    Directory of Open Access Journals (Sweden)

    Lars Nelson

    2015-01-01

    Conclusion: Duodenal stump leaks must be diagnosed as early as possible, and treated appropriately with operative intervention. Regardless of the operative technique the key to appropriate treatment is stabilize the patient, repair the duodenal stump, and adequate drainage.

  6. Multiple-Feature Extracting Modules Based Leak Mining System Design

    Science.gov (United States)

    Cho, Ying-Chiang; Pan, Jen-Yi

    2013-01-01

    Over the years, human dependence on the Internet has increased dramatically. A large amount of information is placed on the Internet and retrieved from it daily, which makes web security in terms of online information a major concern. In recent years, the most problematic issues in web security have been e-mail address leakage and SQL injection attacks. There are many possible causes of information leakage, such as inadequate precautions during the programming process, which lead to the leakage of e-mail addresses entered online or insufficient protection of database information, a loophole that enables malicious users to steal online content. In this paper, we implement a crawler mining system that is equipped with SQL injection vulnerability detection, by means of an algorithm developed for the web crawler. In addition, we analyze portal sites of the governments of various countries or regions in order to investigate the information leaking status of each site. Subsequently, we analyze the database structure and content of each site, using the data collected. Thus, we make use of practical verification in order to focus on information security and privacy through black-box testing. PMID:24453892

  7. Volumetric Survey Speed: A Figure of Merit for Transient Surveys

    CERN Document Server

    Bellm, Eric C

    2016-01-01

    Time-domain surveys can exchange sky coverage for revisit frequency, complicating the comparison of their relative capabilities. By using different revisit intervals, a specific camera may execute surveys optimized for discovery of different classes of transient objects. We propose a new figure of merit, the instantaneous volumetric survey speed, for evaluating transient surveys. This metric defines the trade between cadence interval and snapshot survey volume and so provides a natural means of comparing survey capability. The related metric of areal survey speed imposes a constraint on the range of possible revisit times: we show that many modern time-domain surveys are limited by the amount of fresh sky available each night. We introduce the concept of "spectroscopic accessibility" and discuss its importance for transient science goals requiring followup observing. We present an extension of the control time algorithm for cases where multiple consecutive detections are required. Finally, we explore how surv...

  8. Endoscopic Treatment of Gastrointestinal Perforations, Leaks, and Fistulae.

    Science.gov (United States)

    Rustagi, Tarun; McCarty, Thomas R; Aslanian, Harry R

    2015-01-01

    Gastrointestinal leaks and fistulae are common postoperative complications, whereas intestinal perforation more commonly complicates advanced endoscopic procedures. Although these complications have classically been managed surgically, there exists an ever-expanding role for endoscopic therapy and the involvement of advanced endoscopists as part of a multidisciplinary team including surgeons and interventional radiologists. This review will serve to highlight the innovative endoscopic interventions that provide an expanding range of viable endoscopic approaches to the management and therapy of gastrointestinal perforation, leaks, and fistulae.

  9. Personalized Management of Anastomotic Leak after Surgery for Esophageal Carcinoma

    Institute of Scientific and Technical Information of China (English)

    Hong-yu Ye; Wei-zhao Huang; Yin-meng Wu; Yi Liang; Jun-meng Zheng; Hai-ming Jiang

    2012-01-01

    To summarize the management of anastomotic leak following surgery for esophageal carcinoma.Methods The medical records of the patients developing digestive tract leak after surgery for esophageal carcinoma in our hospital from January 2003 to March 2011 were retrospectively analyzed.Results A total of 36 patients were included,in whom 13 developed cervical anastomotic leak,18 had intra-thoracic anastomotic leak,and 5 had intra-thoracic gastric necrosis.Of these patients,7 were treated with resurgery,6 with esophageal stent implantation,and 23 with conservative treatment.Treatment lasted for 5 to 181 days,averagely 47.0±31.9 days.After management,9 patients died (25.0%).Among seven patients with resurgery,four had deceased,two were cured,and one developed leak again and was switched to conservative treatment until discharged.All the 6 patients treated with stent implantation were cured.Of the 24 patients receiving conservative treatment (including one switched from resurgery),18 (75.0%) were cured and 1 was not cured but survived.Conclusions Anastomotic leak following surgery for esophageal carcinoma should be treated individually based on the onset time,location,size,and extent of the leakage.Conservative treatment is still a safe and effective method.The efficacy of stent implantation needs further investigation to confirm.

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

    Science.gov (United States)

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

    2013-11-01

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

  11. Volumetric polymerization shrinkage of contemporary composite resins

    Directory of Open Access Journals (Sweden)

    Halim Nagem Filho

    2007-10-01

    Full Text Available The polymerization shrinkage of composite resins may affect negatively the clinical outcome of the restoration. Extensive research has been carried out to develop new formulations of composite resins in order to provide good handling characteristics and some dimensional stability during polymerization. The purpose of this study was to analyze, in vitro, the magnitude of the volumetric polymerization shrinkage of 7 contemporary composite resins (Definite, Suprafill, SureFil, Filtek Z250, Fill Magic, Alert, and Solitaire to determine whether there are differences among these materials. The tests were conducted with precision of 0.1 mg. The volumetric shrinkage was measured by hydrostatic weighing before and after polymerization and calculated by known mathematical equations. One-way ANOVA (a or = 0.05 was used to determine statistically significant differences in volumetric shrinkage among the tested composite resins. Suprafill (1.87±0.01 and Definite (1.89±0.01 shrank significantly less than the other composite resins. SureFil (2.01±0.06, Filtek Z250 (1.99±0.03, and Fill Magic (2.02±0.02 presented intermediate levels of polymerization shrinkage. Alert and Solitaire presented the highest degree of polymerization shrinkage. Knowing the polymerization shrinkage rates of the commercially available composite resins, the dentist would be able to choose between using composite resins with lower polymerization shrinkage rates or adopting technical or operational procedures to minimize the adverse effects deriving from resin contraction during light-activation.

  12. A SUBDIVISION SCHEME FOR VOLUMETRIC MODELS

    Institute of Scientific and Technical Information of China (English)

    GhulamMustafa; LiuXuefeng

    2005-01-01

    In this paper, a subdivision scheme which generalizes a surface scheme in previous papers to volume meshes is designed. The scheme exhibits significant control over shrink-age/size of volumetric models. It also has the ability to conveniently incorporate boundaries and creases into a smooth limit shape of models. The method presented here is much simpler and easier as compared to MacCracken and Joy's. This method makes no restrictions on the local topology of meshes. Particularly, it can be applied without any change to meshes of nonmanifold topology.

  13. Volumetric composition in composites and historical data

    DEFF Research Database (Denmark)

    Lilholt, Hans; Madsen, Bo

    2013-01-01

    guidance to the optimal combination of fibre content, matrix content and porosity content, in order to achieve the best obtainable properties. Several composite materials systems have been shown to be handleable with this model. An extensive series of experimental data for the system of cellulose fibres...... and polymer (resin) was produced in 1942 – 1944, and these data have been (re-)analysed by the volumetric composition model, and the property values for density, stiffness and strength have been evaluated. Good agreement has been obtained and some further observations have been extracted from the analysis....

  14. IMITATION OF STANDARD VOLUMETRIC ACTIVITY METAL SAMPLES

    Directory of Open Access Journals (Sweden)

    A. I. Zhukouski

    2016-01-01

    Full Text Available Due to the specific character of problems in the field of ionizing radiation spectroscopy, the R&D and making process of standard volumetric activity metal samples (standard samples for calibration and verification of spectrometric equipment is not only expensive, but also requires the use of highly qualified experts and a unique specific equipment. Theoretical and experimental studies performed have shown the possibility to use imitators as a set of alternating point sources of gamma radiation and metal plates and their use along with standard volumetric activity metal samples for calibration of scintillation-based detectors used in radiation control in metallurgy. Response functions or instrumental spectra of such spectrometer to radionuclides like 137Cs, 134Cs, 152Eu, 154Eu, 60Co, 54Mn, 232Th, 226Ra, 65Zn, 125Sb+125mTe, 106Ru+106Rh, 94Nb, 110mAg, 233U, 234U, 235U and 238U are required for calibration in a given measurement geometry. Standard samples in the form of a probe made of melt metal of a certain diameter and height are used in such measurements. However, the production of reference materials is costly and even problematic for such radionuclides as 94Nb, 125Sb+125mTe, 234U, 235U  etc. A recognized solution to solve this problem is to use the Monte-Carlo simulation method. Instrumental experimental and theoretical spectra obtained by using standard samples and their imitators show a high compliance between experimental spectra of real samples and the theoretical ones of their Monte-Carlo models, between spectra of real samples and the ones of their imitators and finally, between experimental spectra of real sample imitators and the theoretical ones of their Monte-Carlo models. They also have shown the adequacy and consistency of the approach in using a combination of metal scattering layers and reference point gamma-ray sources instead of standard volumetric activity metal samples. As for using several reference point gamma-ray sources

  15. Magnetic volumetric hologram memory with magnetic garnet.

    Science.gov (United States)

    Nakamura, Yuichi; Takagi, Hiroyuki; Lim, Pang Boey; Inoue, Mitsuteru

    2014-06-30

    Holographic memory is a promising next-generation optical memory that has a higher recording density and a higher transfer rate than other types of memory. In holographic memory, magnetic garnet films can serve as rewritable holographic memory media by use of magneto-optical effect. We have now demonstrated that a magnetic hologram can be recorded volumetrically in a ferromagnetic garnet film and that the signal image can be reconstructed from it for the first time. In addition, multiplicity of the magnetic hologram was also confirmed; the image could be reconstructed from a spot overlapped by other spots.

  16. Beyond WikiLeaks implications for the future of communications, journalism and society

    CERN Document Server

    Brevini, Benedetta; McCurdy, Patrick

    2013-01-01

    The 2010 release of US embassy diplomatic cables put WikiLeaks into the international spotlight. Revelations by the leaks sparked intense debate within international diplomacy, journalism and society. This book reflects on the implications of WikiLeaks across politics and media, and on the results of leak journalism and transparency activism.

  17. Applying monitoring, verification, and accounting techniques to a real-world, enhanced oil recovery operational CO2 leak

    Science.gov (United States)

    Wimmer, B.T.; Krapac, I.G.; Locke, R.; Iranmanesh, A.

    2011-01-01

    The use of carbon dioxide (CO2) for enhanced oil recovery (EOR) is being tested for oil fields in the Illinois Basin, USA. While this technology has shown promise for improving oil production, it has raised some issues about the safety of CO2 injection and storage. The Midwest Geological Sequestration Consortium (MGSC) organized a Monitoring, Verification, and Accounting (MVA) team to develop and deploy monitoring programs at three EOR sites in Illinois, Indiana, and Kentucky, USA. MVA goals include establishing baseline conditions to evaluate potential impacts from CO2 injection, demonstrating that project activities are protective of human health and the environment, and providing an accurate accounting of stored CO2. This paper focuses on the use of MVA techniques in monitoring a small CO2 leak from a supply line at an EOR facility under real-world conditions. The ability of shallow monitoring techniques to detect and quantify a CO2 leak under real-world conditions has been largely unproven. In July of 2009, a leak in the pipe supplying pressurized CO2 to an injection well was observed at an MGSC EOR site located in west-central Kentucky. Carbon dioxide was escaping from the supply pipe located approximately 1 m underground. The leak was discovered visually by site personnel and injection was halted immediately. At its largest extent, the hole created by the leak was approximately 1.9 m long by 1.7 m wide and 0.7 m deep in the land surface. This circumstance provided an excellent opportunity to evaluate the performance of several monitoring techniques including soil CO2 flux measurements, portable infrared gas analysis, thermal infrared imagery, and aerial hyperspectral imagery. Valuable experience was gained during this effort. Lessons learned included determining 1) hyperspectral imagery was not effective in detecting this relatively small, short-term CO2 leak, 2) even though injection was halted, the leak remained dynamic and presented a safety risk concern

  18. Leak Isolation in Pressurized Pipelines using an Interpolation Function to approximate the Fitting Losses

    Science.gov (United States)

    Badillo-Olvera, A.; Begovich, O.; Peréz-González, A.

    2017-01-01

    The present paper is motivated by the purpose of detection and isolation of a single leak considering the Fault Model Approach (FMA) focused on pipelines with changes in their geometry. These changes generate a different pressure drop that those produced by the friction, this phenomenon is a common scenario in real pipeline systems. The problem arises, since the dynamical model of the fluid in a pipeline only considers straight geometries without fittings. In order to address this situation, several papers work with a virtual model of a pipeline that generates a equivalent straight length, thus, friction produced by the fittings is taking into account. However, when this method is applied, the leak is isolated in a virtual length, which for practical reasons does not represent a complete solution. This research proposes as a solution to the problem of leak isolation in a virtual length, the use of a polynomial interpolation function in order to approximate the conversion of the virtual position to a real-coordinates value. Experimental results in a real prototype are shown, concluding that the proposed methodology has a good performance.

  19. Measuring Air Leaks into the Vacuum Space of Large Liquid Hydrogen Tanks

    Science.gov (United States)

    Youngquist, Robert; Starr, Stanley; Nurge, Mark

    2012-01-01

    Large cryogenic liquid hydrogen tanks are composed of inner and outer shells. The outer shell is exposed to the ambient environment while the inner shell holds the liquid hydrogen. The region between these two shells is evacuated and typically filled with a powderlike insulation to minimize radiative coupling between the two shells. A technique was developed for detecting the presence of an air leak from the outside environment into this evacuated region. These tanks are roughly 70 ft (approx. equal 21 m) in diameter (outer shell) and the inner shell is roughly 62 ft (approx. equal 19 m) in diameter, so the evacuated region is about 4 ft (approx. equal 1 m) wide. A small leak's primary effect is to increase the boil-off of the tank. It was preferable to install a more accurate fill level sensor than to implement a boil-off meter. The fill level sensor would be composed of an accurate pair of pressure transducers that would essentially weigh the remaining liquid hydrogen. This upgrade, allowing boil-off data to be obtained weekly instead of over several months, is ongoing, and will then provide a relatively rapid indication of the presence of a leak.

  20. A LOW-COST GPR GAS PIPE & LEAK DETECTOR

    Energy Technology Data Exchange (ETDEWEB)

    David Cist; Alan Schutz

    2005-03-30

    A light-weight, easy to use ground penetrating radar (GPR) system for tracking metal/non-metal pipes has been developed. A pre-production prototype instrument has been developed whose production cost and ease of use should fit important market niches. It is a portable tool which is swept back and forth like a metal detector and which indicates when it goes over a target (metal, plastic, concrete, etc.) and how deep it is. The innovation of real time target detection frees the user from having to interpret geophysical data and instead presents targets as dots on the screen. Target depth is also interpreted automatically, relieving the user of having to do migration analysis. In this way the user can simply walk around looking for targets and, by ''connecting the dots'' on the GPS screen, locate and follow pipes in real time. This is the first tool known to locate metal and non-metal pipes in real time and map their location. This prototype design is similar to a metal detector one might use at the beach since it involves sliding a lightweight antenna back and forth over the ground surface. The antenna is affixed to the end of an extension that is either clipped to or held by the user. This allows him to walk around in any direction, either looking for or following pipes with the antenna location being constantly recorded by the positioning system. Once a target appears on the screen, the user can locate by swinging the unit to align the cursor over the dot. Leak detection was also a central part of this project, and although much effort was invested into its development, conclusive results are not available at the time of the writing of this document. Details of the efforts that were made as a part of this cooperative agreement are presented.

  1. ENVIRONMENTAL MONITORING OF LEAKS USING TIME LAPSED LONG ELECTRODE ELECTRICAL RESISTIVITY

    Energy Technology Data Exchange (ETDEWEB)

    MYERS DA; RUCKER DF; FINK JB; LOKE MH

    2009-12-16

    Highly industrialized areas pose challenges for surface electrical resistivity characterization due to metallic infrastructure. The infrastructure is typically more conductive than the desired targets and will mask the deeper subsurface information. These challenges may be minimized if steel-cased wells are used as long electrodes in the area near the target. We demonstrate a method of using long electrodes to electrically monitor a simulated leak from an underground storage tank with both synthetic examples and a field demonstration. The synthetic examples place a simple target of varying electrical properties beneath a very low resistivity layer. The layer is meant to replicate the effects of infrastructure. Both surface and long electrodes are tested on the synthetic domain. The leak demonstration for the field experiment is simulated by injecting a high conductivity fluid in a perforated well within the S tank farm at Hanford, and the resistivity measurements are made before and after the leak test. All data are processed in four dimensions, where a regularization procedure is applied in both the time and space domains. The synthetic test case shows that the long electrode ERM could detect relative changes in resistivity that are commensurate with the differing target properties. The surface electrodes, on the other hand, had a more difficult time matching the original target's footprint. The field results shows a lowered resistivity feature develop south of the injection site after cessation of the injections. The time lapsed regularization parameter has a strong influence on the differences in inverted resistivity between the pre and post injection datasets, but the interpretation of the target is consistent across all values of the parameter. The long electrode ERM method may provide a tool for near real-time monitoring of leaking underground storage tanks.

  2. Surgical challenge: endoscopic repair of cerebrospinal fluid leak

    Directory of Open Access Journals (Sweden)

    Martín-Martín Carlos

    2012-08-01

    Full Text Available Abstract Background Cerebrospinal fluid leaks (CSF result from an abnormal communication between the subarachnoid space and the extracranial space. Approximately 90% of CSF leak at the anterior skull base manifests as rhinorrhea and can become life-threatening condition. Endoscopic sinus surgery (ESS has become a common otolaryngologist procedure. The aim of this article is to consider our experience and to evaluate the outcomes in patients who underwent a purely endoscopic repair of CSF leaks of the anterior skull base. Findings Retrospective chart review was performed of all patients surgically treated for CSF leaks presenting to the Section of Nasal and Sinus Disorders at the Service of ENT–Head and Neck Surgery, University Hospital Complex of Santiago de Compostela (CHUS, between 2004 and 2010. A total of 30 patients who underwent repair CSF leak by ESS. The success rate was 93.4% at the first attempt; only two patients (6.6% required a second surgical procedure, and none of it was necessary to use a craniotomy for closure. Follow-up periods ranged from 4 months to 6 years. Conclusion Identifying the size, site, and etiology of the CSF leak remains the most important factor in the surgical success. It is generally accepted that the ESS have made procedures minimally invasive, and CSF leak is now one of its well-established indications with low morbidity and high success rate, with one restriction for fistulas of the posterior wall of the frontal sinus should be repaired in conjunction with open techniques.

  3. Infrared Camera System for Visualization of IR-Absorbing Gas Leaks

    Science.gov (United States)

    Youngquist, Robert; Immer, Christopher; Cox, Robert

    2010-01-01

    Leak detection and location remain a common problem in NASA and industry, where gas leaks can create hazardous conditions if not quickly detected and corrected. In order to help rectify this problem, this design equips an infrared (IR) camera with the means to make gas leaks of IR-absorbing gases more visible for leak detection and location. By comparing the output of two IR cameras (or two pictures from the same camera under essentially identical conditions and very closely spaced in time) on a pixel-by-pixel basis, one can cancel out all but the desired variations that correspond to the IR absorption of the gas of interest. This can be simply done by absorbing the IR lines that correspond to the gas of interest from the radiation received by one of the cameras by the intervention of a filter that removes the particular wavelength of interest from the "reference" picture. This can be done most sensitively with a gas filter (filled with the gas of interest) placed in front of the IR detector array, or (less sensitively) by use of a suitable line filter in the same location. This arrangement would then be balanced against the unfiltered "measurement" picture, which will have variations from IR absorption from the gas of interest. By suitable processing of the signals from each pixel in the two IR pictures, the user can display only the differences in the signals. Either a difference or a ratio output of the two signals is feasible. From a gas concentration viewpoint, the ratio could be processed to show the column depth of the gas leak. If a variation in the background IR light intensity is present in the field of view, then large changes in the difference signal will occur for the same gas column concentration between the background and the camera. By ratioing the outputs, the same signal ratio is obtained for both high- and low-background signals, even though the low-signal areas may have greater noise content due to their smaller signal strength. Thus, one

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

    Science.gov (United States)

    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 training, 10% (5-37%) directly after training and 15% (4-33%) 3 weeks later (ptraining 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. Disentangling volumetric and hydrational properties of proteins.

    Science.gov (United States)

    Voloshin, Vladimir P; Medvedev, Nikolai N; Smolin, Nikolai; Geiger, Alfons; Winter, Roland

    2015-02-05

    We used molecular dynamics simulations of a typical monomeric protein, SNase, in combination with Voronoi-Delaunay tessellation to study and analyze the temperature dependence of the apparent volume, Vapp, of the solute. We show that the void volume, VB, created in the boundary region between solute and solvent, determines the temperature dependence of Vapp to a major extent. The less pronounced but still significant temperature dependence of the molecular volume of the solute, VM, is essentially the result of the expansivity of its internal voids, as the van der Waals contribution to VM is practically independent of temperature. Results for polypeptides of different chemical nature feature a similar temperature behavior, suggesting that the boundary/hydration contribution seems to be a universal part of the temperature dependence of Vapp. The results presented here shine new light on the discussion surrounding the physical basis for understanding and decomposing the volumetric properties of proteins and biomolecules in general.

  6. All Photons Imaging Through Volumetric Scattering

    Science.gov (United States)

    Satat, Guy; Heshmat, Barmak; Raviv, Dan; Raskar, Ramesh

    2016-01-01

    Imaging through thick highly scattering media (sample thickness ≫ mean free path) can realize broad applications in biomedical and industrial imaging as well as remote sensing. Here we propose a computational “All Photons Imaging” (API) framework that utilizes time-resolved measurement for imaging through thick volumetric scattering by using both early arrived (non-scattered) and diffused photons. As opposed to other methods which aim to lock on specific photons (coherent, ballistic, acoustically modulated, etc.), this framework aims to use all of the optical signal. Compared to conventional early photon measurements for imaging through a 15 mm tissue phantom, our method shows a two fold improvement in spatial resolution (4db increase in Peak SNR). This all optical, calibration-free framework enables widefield imaging through thick turbid media, and opens new avenues in non-invasive testing, analysis, and diagnosis. PMID:27683065

  7. A Technique for Volumetric CSG Based on Morphology

    DEFF Research Database (Denmark)

    Bærentzen, Jakob Andreas; Christensen, Niels Jørgen

    2001-01-01

    In this paper, a new technique for volumetric CSG is presented. The technique requires the input volumes to correspond to solids which fulfill a voxelization suitability criterion. Assume the CSG operation is union. The volumetric union of two such volumes is defined in terms of the voxelization...

  8. Echocardiographic findings in patients with spontaneous CSF leak.

    Science.gov (United States)

    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.

  9. The Soil Microbial Response to a Massive Natural Gas Leak

    Science.gov (United States)

    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.

  10. The causes and functions of mitochondrial proton leak.

    Science.gov (United States)

    Brand, M D; Chien, L F; Ainscow, E K; Rolfe, D F; Porter, R K

    1994-08-30

    The non-linear relationship between respiration rate and protonmotive force in isolated mitochondria is explained entirely by delta p-dependent changes in the proton conductance of the mitochondrial inner membrane and is not caused by redox slip in the proton pumps. Mitochondrial proton leak occurs in intact cells and tissues: the futile cycle of proton pumping and proton leak accounts for 26% +/- 7% of the total oxygen consumption rate or 33% +/- 7% of the mitochondrial respiration rate of isolated hepatocytes (mean +/- S.D. for 43 rats); 52% of the oxygen consumption rate of resting perfused muscle and up to 38% of the basal metabolic rate of a rat, suggesting that heat production may be an important function in the proton leak in homeotherms. Together with non-mitochondrial oxygen consumption, it lowers the effective P/O ratio in cells from maximum possible values of 2.33 (palmitate oxidation) or 2.58 (glucose oxidation) to as low as 1.1 in liver or 0.8 in muscle. The effective P/O ratio increases in response to ATP demand; the ability to allow rapid switching of flux from leak to ATP turnover may be an even more important function of the leak reaction than heat production. The mitochondrial proton conductance in isolated mitochondria and in hepatocytes is greatly modulated by thyroid hormones, by phylogeny and by body mass. Usually the reactions of ATP turnover change in parallel so that the coupling ratio is not greatly affected. Changes in proton leak in tissues are brought about in the short term by changes in mitochondrial protonmotive force and in the longer term by changes in the surface area and proton permeability of the mitochondrial inner membrane. Permeability changes are probably caused by changes in the fatty acid composition of the membrane phospholipids.

  11. Effects of Different Reconstruction Parameters on CT Volumetric Measurement 
of Pulmonary Nodules

    Directory of Open Access Journals (Sweden)

    Rongrong YANG

    2012-02-01

    Full Text Available Background and objective It has been proven that volumetric measurements could detect subtle changes in small pulmonary nodules in serial CT scans, and thus may play an important role in the follow-up of indeterminate pulmonary nodules and in differentiating malignant nodules from benign nodules. The current study aims to evaluate the effects of different reconstruction parameters on the volumetric measurements of pulmonary nodules in chest CT scans. Methods Thirty subjects who underwent chest CT scan because of indeterminate pulmonary nodules in General Hospital of Tianjin Medical University from December 2009 to August 2011 were retrospectively analyzed. A total of 52 pulmonary nodules were included, and all CT data were reconstructed using three reconstruction algorithms and three slice thicknesses. The volumetric measurements of the nodules were performed using the advanced lung analysis (ALA software. The effects of the reconstruction algorithms, slice thicknesses, and nodule diameters on the volumetric measurements were assessed using the multivariate analysis of variance for repeated measures, the correlation analysis, and the Bland-Altman method. Results The reconstruction algorithms (F=13.6, P<0.001 and slice thicknesses (F=4.4, P=0.02 had significant effects on the measured volume of pulmonary nodules. In addition, the coefficients of variation of nine measurements were inversely related with nodule diameter (r=-0.814, P<0.001. The volume measured at the 2.5 mm slice thickness had poor agreement with the volumes measured at 1.25 mm and 0.625 mm, respectively. Moreover, the best agreement was achieved between the slice thicknesses of 1.25 mm and 0.625 mm using the bone algorithm. Conclusion Reconstruction algorithms and slice thicknesses have significant impacts on the volumetric measurements of lung nodules, especially for the small nodules. Therefore, the reconstruction setting in serial CT scans should be consistent in the follow

  12. Endoscopic management of biliary leaks after laparoscopic cholecystectomy.

    Science.gov (United States)

    Rustagi, Tarun; Aslanian, Harry R

    2014-09-01

    Laparoscopic cholecystectomy has become the procedure of choice for management of symptomatic cholelithiasis. Although it has distinct advantages over open cholecystectomy, bile leak is more common. Endoscopic retrograde cholangiopancreatography is the diagnostic and therapeutic modality of choice for management of postcholecystectomy bile leaks and has a high success rate with the placement of plastic biliary stents. Repeat endoscopic retrograde cholangiopancreatography with placement of multiple plastic stents, a covered metal stent, or possibly cyanoacrylate therapy may be effective in refractory cases. This review will discuss the indications, efficacy, and complications of endoscopic therapy.

  13. Gas leak effects on environment of Ostrava Basin

    Energy Technology Data Exchange (ETDEWEB)

    Prokop, P. [VSB - Technical University of Ostrava (Czech Republic). Institute of Safety Engineering, Faculty of Mining and Geology

    2001-07-01

    This paper is a contribution to the range of problems which are very serious from the safety, environmental, technical and economic viewpoints. In correspondence to the attenuation and shut-down of coal mining in the OKR mining district, the opinions have been developing on the gas conditions in the abandoned mines and the safety hazards related to those conditions and to the gas leak to the surface. Accidents and emergency situations which have lately appeared in the OKR mining district have induced the intensive effort paid to the solution of risk of gas leak to the surface including all the related problems. 2 refs.

  14. Cervical intradural disc herniation and cerebrospinal fluid leak

    Directory of Open Access Journals (Sweden)

    Ritesh Kansal

    2011-01-01

    Full Text Available Cervical intradural disc herniation (IDH is a rare condition and only 25 cases of cervical have been reported. We report a 45-year-old male who presented with sudden onset right lower limb weakness after lifting heavy weight. Magnetic resonance imaging of the cervical spine showed C5/6 disc prolapse with intradural extension. The patient underwent C5/6 discectomy through anterior cervical approach. Postoperatively, the patient improved in stiffness but developed cerebrospinal fluid leak and the leak resolved with multiple lumbar punctures.

  15. Modal analysis of acoustic leak signal in pipelines using time-frequency analysis

    Institute of Scientific and Technical Information of China (English)

    JIAO Jing-pin; FEI Ren-yuan; HE Cun-fu; WU Bin

    2006-01-01

    It is important to analyze the propagation characteristics of guided waves in acoustic leak location in pipelines.In this paper,the acoustic leak signal is analyzed in the time-frequency domain.Based on the relation of time-frequency distribution of the acoustic leak signal and the dispersion curves of guided waves,the mode components of acoustic leak signals were obtained.The research can provide a guideline for the mode selection in pipeline leak location,and help improve the accuracy of leak location.

  16. [Effects of palmitic acid on activity of uncoupling proteins and proton leak in in vitro cerebral mitochondria from the rats exposed to simulated high altitude hypoxia].

    Science.gov (United States)

    Xu, Yu; Liu, Jun-Ze; Xia, Chen

    2008-02-25

    To reveal the roles of uncoupling proteins (UCPs) in disorder of mitochondrial oxidative phosphorylation induced by free fatty acid during hypoxic exposure, the effects of palmitic acid on activity of UCPs, proton leak and mitochondrial membrane potential in hypoxia-exposed rat brain mitochondria were observed in vitro. Adult Sprague-Dawley (SD) rats were set randomly into control, acute hypoxia and chronic hypoxia groups (n=8 in each group). The acute and chronic hypoxic rats were exposed to simulated 5000 m high altitude in a hypobaric chamber 23 h/d for 3 d and 30 d, respectively. The brain mitochondria were isolated by centrifugation. UCP content and activity were detected by [(3)H]-GTP binding method. The proton leak was measured by TPMP(+) electrode and oxygen electrode. The membrane potential of mitochondria was calculated by detecting the fluorescence from Rodamine 123. Hypoxic exposure resulted in an increase in UCP activity and content as well as proton leak, but a decrease in the membrane potential of rat brain mitochondria. Palmitic acid resulted in further increases in UCP activity and content as well as proton leak, and further decrease in membrane potential of brain mitochondria in vitro from hypoxia-exposed rats, but hypoxic exposure decreased the reactivity of cerebral mitochondria to palmitic acid, especially in the acute hypoxia group. There was a negative correlation between mitochondrial proton leak and K(d) value (representing derivative of UCP activity, PB(max) (representing the maximal content of UCPs in mitochondrial inner membrane, P<0.01, r = 0.856). Cerebral mitochondrial membrane potential was negatively correlated with proton leak (P<0.01, r = -0.880). It is suggested that hypoxia-induced proton leak enhancement and membrane potential decrease are correlated with the increased activity of UCPs. Hypoxia can also decrease the sensitivity of cerebral mitochondria to palmitic acid, which may be a self-protective mechanism in high altitude

  17. Theoretical and Experimental Estimations of Volumetric Inductive Phase Shift in Breast Cancer Tissue

    Science.gov (United States)

    González, C. A.; Lozano, L. M.; Uscanga, M. C.; Silva, J. G.; Polo, S. M.

    2013-04-01

    Impedance measurements based on magnetic induction for breast cancer detection has been proposed in some studies. This study evaluates theoretical and experimentally the use of a non-invasive technique based on magnetic induction for detection of patho-physiological conditions in breast cancer tissue associated to its volumetric electrical conductivity changes through inductive phase shift measurements. An induction coils-breast 3D pixel model was designed and tested. The model involves two circular coils coaxially centered and a human breast volume centrally placed with respect to the coils. A time-harmonic numerical simulation study addressed the effects of frequency-dependent electrical properties of tumoral tissue on the volumetric inductive phase shift of the breast model measured with the circular coils as inductor and sensor elements. Experimentally; five female volunteer patients with infiltrating ductal carcinoma previously diagnosed by the radiology and oncology departments of the Specialty Clinic for Women of the Mexican Army were measured by an experimental inductive spectrometer and the use of an ergonomic inductor-sensor coil designed to estimate the volumetric inductive phase shift in human breast tissue. Theoretical and experimental inductive phase shift estimations were developed at four frequencies: 0.01, 0.1, 1 and 10 MHz. The theoretical estimations were qualitatively in agreement with the experimental findings. Important increments in volumetric inductive phase shift measurements were evident at 0.01MHz in theoretical and experimental observations. The results suggest that the tested technique has the potential to detect pathological conditions in breast tissue associated to cancer by non-invasive monitoring. Further complementary studies are warranted to confirm the observations.

  18. Automatic leak location in a pipe; Localizador automatico de fugas en un ducto

    Energy Technology Data Exchange (ETDEWEB)

    Carrera Mendez, Rolando; Verde Rodarte, Cristina [Universidad Nacional Autonoma de Mexico (Mexico)

    2001-06-01

    A real time method for detecting and locating leaks in pipes is analysed. By monitoring pressure gradients of a pipe in a steady state operation, expressions that indicate the existence of a leak and its location are derived. For small leaks it is possible to deduce alternative expressions based on in- and outflow deviations from their normal values. These deviations are estimated by means of a nonlinear dynamic flow observer. It is an easy task to carry out this system and the detection and location algorithm require low resource. As a result of this analysis it was found that the identifier is very sensitive to variations of the D'Arcy-Weissbach friction. [Spanish] Se describe y analiza un metodo que permite detectar y ubicar fugas de liquidos en un ducto sin tomas laterales en tiempo real. A partir de una operacion en estado permanente y del monitoreo de los gradientes de presion en los extremos de la tuberia, se derivan expresiones que permiten detectar la existencia de una fuga y su localizacion. Tambien se muestra que para fugas pequenas se pueden obtener expresiones alternativas para la deteccion y localizacion, basadas en las desviaciones de los flujos con respecto a sus valores nominales. Dicha desviacion se estima con un observador dinamico no lineal del comportamiento de flujo. La realizacion es de facil implantacion y el algoritmo se deteccion y localizacion requiere de pocos recursos de computacion. Del analisis presentado se desprende que el localizador es muy sensible a las variaciones en la estimacion de la friccion de D'Arcy-Weissbach del ducto.

  19. A Study on the Evaluation of Valve Leak Rates Using Acoustic Emission Technique

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Guk; Lee, Jun Shin; Lee, Sun Ki; Shon, Seok Man; Lee, Wook Ryun; Kim, Tae Ryong [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Lim, Yong Jae; Choo, Kee Young [Hana Evertech Co., Seongnam (Korea, Republic of)

    2005-07-01

    The objective of this study is to estimate the feasibility of acoustic emission method for the internal leak from the valves. In this study, two types of valve(a 3 1/2 inch glove valve for 600 psi steam and a 4 inch ball valve water ) leak tests using three different leak path and numerous leak rates were performed in order to analyze acoustic emission properties when leaks arise in valve seat. As a result of leak test for specimens simulated valve seat, we conformed that leak sound amplitude increased in proportion to the increase of leak rate, and leak rates were plotted versus peak acoustic amplitudes recorded within those two narrow frequency bands on each spectral plot. The resulting plots of leak rate versus peak acoustic amplitude were the primary basis for determining the feasibility of quantifying leak acoustically. The large amount of data collected also allowed a grief investigation of the effects of different leak paths, leakage rates, pressure differentials and transducers on the acoustic amplitude spectra. From the experimental results, it was suggested that the acoustic emission method for monitoring of leak was feasible.

  20. Volumetric measurement of pulmonary nodules at low-dose chest CT : effect of reconstruction setting on measurement variability

    NARCIS (Netherlands)

    Wang, Y.; de Bock, G.H.; van Klaveren, R.J.; van Ooyen, P.; Tukker, W.; Zhao, Y.; Dorrius, M.D.; Proenca, R.V.; Post, W.J.; Oudkerk, M.

    2010-01-01

    To assess volumetric measurement variability in pulmonary nodules detected at low-dose chest CT with three reconstruction settings. The volume of 200 solid pulmonary nodules was measured three times using commercially available semi-automated software of low-dose chest CT data-sets reconstructed wit

  1. 40 CFR 63.1331 - Equipment leak provisions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Equipment leak provisions. 63.1331 Section 63.1331 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... polymer fluid used to provide lubrication and/or cooling of the pump or agitator shaft exits the...

  2. Gender Inequality at Universities and the ‘Leaking Pipeline’

    DEFF Research Database (Denmark)

    Emerek, Ruth; Larsen, Britt Østergaard

    2010-01-01

    Research shows that the correlation - the higher the level of academic positions at universities the lower the percentage of women among employees - also applies at Danish universities (Ståhle, 2007). This may be due to a historic back log or merely to a ’Leaking pipeline’, as earlier studies have...

  3. Gender Inequality at Universities and the ‘Leaking Pipeline’

    DEFF Research Database (Denmark)

    Emerek, Ruth; Larsen, Britt Østergaard

    2010-01-01

    Research shows that the correlation - the higher the level of academic positions at universities the lower the percentage of women among employees - also applies at Danish universities (Ståhle, 2007). This may be due to a historic back log or merely to a ’Leaking pipeline’, as earlier studies hav...

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

    Science.gov (United States)

    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…

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

    Science.gov (United States)

    2010-01-01

    ... wipe sample must be taken from the nearest accessible point to the sealed source where contamination might accumulate. The wipe sample must be analyzed for radioactive contamination. The analysis must be... equipment associated with the leaking source for radioactive contamination and, if contaminated, have it...

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

    Science.gov (United States)

    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.

  7. Some factors affecting the valinomycin-induced leak from liposomes

    NARCIS (Netherlands)

    Blok, M.C.; Gier, J. de; Deenen, L.L.M. van

    1974-01-01

    Experiments dealing with the valinomycin-induced K+ leak from egg lecithin liposomes have demonstrated the importance of the enclosed anion. Except when lipophilic anions are enclosed, the addition of both valinomycin and a uncoupler, e.g. carbonylcyanide p-trifluoromethoxyphenylhydrazone, is necess

  8. 40 CFR 63.148 - Leak inspection provisions.

    Science.gov (United States)

    2010-07-01

    ... inspections for visible, audible, or olfactory indications of leaks. (2) If the vapor collection system or... provisions. (a) Except as provided in paragraph (k) of this section, for each vapor collection system, closed-vent system, fixed roof, cover, or enclosure required to comply with this section, the owner...

  9. Dental volumetric tomographical evaluation of location and prevalence of maxillary sinus septa

    Directory of Open Access Journals (Sweden)

    Ibrahim Damlar

    2013-06-01

    Full Text Available Purpose: The aim of this study was to determine the prevalence and location of maxillary sinus septa with the help of dental volumetric tomography. Methods: 760 patients’ 1520 maxillary sinus were evaluated by dental volumetric tomography for detecting maxillary sinus septa. Maxillary sinus was divided into 3 zones (anterior, middle and posterior zones while location of the maxillary sinus septa. Results: 47 of maxillary sinus septa existed in the anterior zone (24.7%, 35 of them in the middle zone (18.4% and 108 of them in the posterior region (56.8%. Conclusion: The formation of the maxillary sinus septa was affected by the existence or lack of the teeth. Correct detection of the presence of maxillary sinus septa was important prior to sinus lifting and dental implant surgery. Dental volumetric tomographical evaluation of maxillary sinus septa was more useful for a correct diagnosis and treatment planning. [Cukurova Med J 2013; 38(3.000: 467-474

  10. Soil volumetric water content measurements using TDR technique

    Directory of Open Access Journals (Sweden)

    S. Vincenzi

    1996-06-01

    Full Text Available A physical model to measure some hydrological and thermal parameters in soils will to be set up. The vertical profiles of: volumetric water content, matric potential and temperature will be monitored in different soils. The volumetric soil water content is measured by means of the Time Domain Reflectometry (TDR technique. The result of a test to determine experimentally the reproducibility of the volumetric water content measurements is reported together with the methodology and the results of the analysis of the TDR wave forms. The analysis is based on the calculation of the travel time of the TDR signal in the wave guide embedded in the soil.

  11. Leaks in nuclear grade high efficiency aerosol filters

    Energy Technology Data Exchange (ETDEWEB)

    Scripsick, Ronald Clyde [Univ. of California, Davis, CA (United States)

    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.

  12. Iterative reconstruction of volumetric particle distribution

    Science.gov (United States)

    Wieneke, Bernhard

    2013-02-01

    For tracking the motion of illuminated particles in space and time several volumetric flow measurement techniques are available like 3D-particle tracking velocimetry (3D-PTV) recording images from typically three to four viewing directions. For higher seeding densities and the same experimental setup, tomographic PIV (Tomo-PIV) reconstructs voxel intensities using an iterative tomographic reconstruction algorithm (e.g. multiplicative algebraic reconstruction technique, MART) followed by cross-correlation of sub-volumes computing instantaneous 3D flow fields on a regular grid. A novel hybrid algorithm is proposed here that similar to MART iteratively reconstructs 3D-particle locations by comparing the recorded images with the projections calculated from the particle distribution in the volume. But like 3D-PTV, particles are represented by 3D-positions instead of voxel-based intensity blobs as in MART. Detailed knowledge of the optical transfer function and the particle image shape is mandatory, which may differ for different positions in the volume and for each camera. Using synthetic data it is shown that this method is capable of reconstructing densely seeded flows up to about 0.05 ppp with similar accuracy as Tomo-PIV. Finally the method is validated with experimental data.

  13. Prevention of bile leak after liver surgery: A fool-proof method

    Directory of Open Access Journals (Sweden)

    Pujahari Aswini

    2009-01-01

    Full Text Available Background/Aim: Bile leak is not uncommon after liver surgeries. There is no adequate method described to prevent this morbid complication. Materials and Methods: At the end of the liver procedure, transcystic normal saline was injected under pressure with distal clamping. Leaking saline on the cut surface of the liver was sutured. The process was repeated till no leaking was observed. A suction drain was kept for any bile leak. Results: Open liver resection and hydatid cyst surgery cases were included. There were 24 cases, with 13 males and 11 females. The age range was from 4 to 80 years, with a mean of 48 years (SD ± 17.7. The number of leak sites that could be sutured were 0-4 (mean of 2.3 ± 0.5. None had bile leak postoperatively. Conclusion: Transcystic injection under pressure with distal clamping demonstrates the leak sites. Suturing them prevents the postoperative bile leak.

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

    Science.gov (United States)

    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.

  15. 使用Visual Leak Detector检测c/c++程序内存泄漏%Memory Leak Detection in c/c++ Programs with Visual Leak Detector

    Institute of Scientific and Technical Information of China (English)

    杨磊; 汪仁煌; 刘洪江; 黄颖怡

    2008-01-01

    针对内存泄漏检测问题,本文通过示例说明使用软件Visual Leal Detector 来检测泄漏点的方法.通过实验说明该方法在检测一般的c/c++程序内存泄漏时,可以提高检测效率.

  16. Connectivity network measures predict volumetric atrophy in mild cognitive impairment.

    Science.gov (United States)

    Nir, Talia M; Jahanshad, Neda; Toga, Arthur W; Bernstein, Matt A; Jack, Clifford R; Weiner, Michael W; Thompson, Paul M

    2015-01-01

    Alzheimer's disease (AD) is characterized by cortical atrophy and disrupted anatomic connectivity, and leads to abnormal interactions between neural systems. Diffusion-weighted imaging (DWI) and graph theory can be used to evaluate major brain networks and detect signs of a breakdown in network connectivity. In a longitudinal study using both DWI and standard magnetic resonance imaging (MRI), we assessed baseline white-matter connectivity patterns in 30 subjects with mild cognitive impairment (MCI, mean age 71.8 ± 7.5 years, 18 males and 12 females) from the Alzheimer's Disease Neuroimaging Initiative. Using both standard MRI-based cortical parcellations and whole-brain tractography, we computed baseline connectivity maps from which we calculated global "small-world" architecture measures, including mean clustering coefficient and characteristic path length. We evaluated whether these baseline network measures predicted future volumetric brain atrophy in MCI subjects, who are at risk for developing AD, as determined by 3-dimensional Jacobian "expansion factor maps" between baseline and 6-month follow-up anatomic scans. This study suggests that DWI-based network measures may be a novel predictor of AD progression.

  17. 49 CFR 192.717 - Transmission lines: Permanent field repair of leaks.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Transmission lines: Permanent field repair of... § 192.717 Transmission lines: Permanent field repair of leaks. Each permanent field repair of a leak on a transmission line must be made by— (a) Removing the leak by cutting out and replacing...

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

    Energy Technology Data Exchange (ETDEWEB)

    Washenfelder, Dennis J. [Washington River Protection Solutions, Richland, WA (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Girardot, Crystal L. [Washington River Protection Systems, Richland, WA (United States); Harlow, Donald G. [Washington River Protection Systems, Richland, WA (United States)

    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.

  20. Volumetric capnography for the evaluation of chronic airways diseases

    Directory of Open Access Journals (Sweden)

    Veronez L

    2014-09-01

    Full Text Available Liliani de Fátima Veronez,1 Monica Corso Pereira,2 Silvia Maria Doria da Silva,2 Luisa Affi Barcaui,2 Eduardo Mello De Capitani,2 Marcos Mello Moreira,2 Ilma Aparecida Paschoalz2 1Department of Physical Therapy, University of Votuporanga (Educational Foundation of Votuporanga, Votuporanga, 2Department of Internal Medicine, School of Medical Sciences, State University of Campinas (UNICAMP, Campinas, Sao Paulo, BrazilBackground: Obstructive lung diseases of different etiologies present with progressive peripheral airway involvement. The peripheral airways, known as the silent lung zone, are not adequately evaluated with conventional function tests. The principle of gas washout has been used to detect pulmonary ventilation inhomogeneity and to estimate the location of the underlying disease process. Volumetric capnography (VC analyzes the pattern of CO2 elimination as a function of expired volume.Objective: To measure normalized phase 3 slopes with VC in patients with non-cystic fibrosis bronchiectasis (NCB and in bronchitic patients with chronic obstructive pulmonary disease (COPD in order to compare the slopes obtained for the groups.Methods: NCB and severe COPD were enrolled sequentially from an outpatient clinic (Hospital of the State University of Campinas. A control group was established for the NCB group, paired by sex and age. All subjects performed spirometry, VC, and the 6-Minute Walk Test (6MWT. Two comparisons were made: NCB group versus its control group, and NCB group versus COPD group. The project was approved by the ethical committee of the institution. Statistical tests used were Wilcoxon or Student’s t-test; P<0.05 was considered to be a statistically significant difference.Results: Concerning the NCB group (N=20 versus the control group (N=20, significant differences were found in body mass index and in several functional variables (spirometric, VC, 6MWT with worse results observed in the NCB group. In the comparison between

  1. Widespread Volumetric Brain Changes following Tooth Loss in Female Mice

    Science.gov (United States)

    Avivi-Arber, Limor; Seltzer, Ze'ev; Friedel, Miriam; Lerch, Jason P.; Moayedi, Massieh; Davis, Karen D.; Sessle, Barry J.

    2017-01-01

    Tooth loss is associated with altered sensory, motor, cognitive and emotional functions. These changes vary highly in the population and are accompanied by structural and functional changes in brain regions mediating these functions. It is unclear to what extent this variability in behavior and function is caused by genetic and/or environmental determinants and which brain regions undergo structural plasticity that mediates these changes. Thus, the overall goal of our research program is to identify genetic variants that control structural and functional plasticity following tooth loss. As a step toward this goal, here our aim was to determine whether structural magnetic resonance imaging (sMRI) is sensitive to detect quantifiable volumetric differences in the brains of mice of different genetic background receiving tooth extraction or sham operation. We used 67 adult female mice of 7 strains, comprising the A/J (A) and C57BL/6J (B) strains and a randomly selected sample of 5 of the 23 AXB-BXA strains (AXB1, AXB4, AXB24, BXA14, BXA24) that were produced from the A and B parental mice by recombinations and inbreeding. This panel of 25 inbred strains of genetically diverse inbred strains of mice is used for mapping chromosomal intervals throughout the genome that harbor candidate genes controlling the phenotypic variance of any trait under study. Under general anesthesia, 39 mice received extraction of 3 right maxillary molar teeth and 28 mice received sham operation. On post-extraction day 21, post-mortem whole-brain high-resolution sMRI was used to quantify the volume of 160 brain regions. Compared to sham operation, tooth extraction was associated with a significantly reduced regional and voxel-wise volumes of cortical brain regions involved in processing somatosensory, motor, cognitive and emotional functions, and increased volumes in subcortical sensorimotor and temporal limbic forebrain regions including the amygdala. Additionally, comparison of the 10 BXA14

  2. Sensitivity of collapsed arc QA method for delivery errors in Volumetric Modulated Arc Therapy (VMAT)

    Science.gov (United States)

    Young, Tony; Xing, Aitang; Vial, Philp; Thwaites, David; Holloway, Lois; Arumugam, Sankar

    2015-01-01

    In this paper the sensitivity of an Electronic Portal Imaging Device (EPID) to detecting introduced Volumetric Arc Therapy (VMAT) treatment errors was studied using the Collapsed Arc method. Two clinical Head and Neck (H&N) and Prostate treatment plans had gantry dependent dose and MLC errors introduced to the plans. These plans were then delivered to an Elekta Synergy Linear Accelerator EPID and compared to the original treatment planning system Collapsed Arc dose matrix. With the Collapsed Arc technique the EPID was able to detect MLC errors down to 2mm and dose errors of down to 3% depending on the treatment plan complexity and gamma tolerance used.

  3. Characterizing volumetric deformation behavior of naturally occuring bituminous sand materials

    CSIR Research Space (South Africa)

    Anochie-Boateng, Joseph

    2009-05-01

    Full Text Available newly proposed hydrostatic compression test procedure. The test procedure applies field loading conditions of off-road construction and mining equipment to closely simulate the volumetric deformation and stiffness behaviour of oil sand materials. Based...

  4. Hyperspectral image classification based on volumetric texture and dimensionality reduction

    Science.gov (United States)

    Su, Hongjun; Sheng, Yehua; Du, Peijun; Chen, Chen; Liu, Kui

    2015-06-01

    A novel approach using volumetric texture and reduced-spectral features is presented for hyperspectral image classification. Using this approach, the volumetric textural features were extracted by volumetric gray-level co-occurrence matrices (VGLCM). The spectral features were extracted by minimum estimated abundance covariance (MEAC) and linear prediction (LP)-based band selection, and a semi-supervised k-means (SKM) clustering method with deleting the worst cluster (SKMd) bandclustering algorithms. Moreover, four feature combination schemes were designed for hyperspectral image classification by using spectral and textural features. It has been proven that the proposed method using VGLCM outperforms the gray-level co-occurrence matrices (GLCM) method, and the experimental results indicate that the combination of spectral information with volumetric textural features leads to an improved classification performance in hyperspectral imagery.

  5. Designing remote web-based mechanical-volumetric flow meter ...

    African Journals Online (AJOL)

    ... remote web-based mechanical-volumetric flow meter reading systems based on ... damage and also provides the ability to control and manage consumption. ... existing infrastructure of the telecommunications is used in data transmission.

  6. Increasing the volumetric efficiency of Diesel engines by intake pipes

    Science.gov (United States)

    List, Hans

    1933-01-01

    Development of a method for calculating the volumetric efficiency of piston engines with intake pipes. Application of this method to the scavenging pumps of two-stroke-cycle engines with crankcase scavenging and to four-stroke-cycle engines. The utility of the method is demonstrated by volumetric-efficiency tests of the two-stroke-cycle engines with crankcase scavenging. Its practical application to the calculation of intake pipes is illustrated by example.

  7. Serial volumetric registration of pulmonary CT studies

    Science.gov (United States)

    Silva, José Silvestre; Silva, Augusto; Sousa Santos, Beatriz

    2008-03-01

    Detailed morphological analysis of pulmonary structures and tissue, provided by modern CT scanners, is of utmost importance as in the case of oncological applications both for diagnosis, treatment, and follow-up. In this case, a patient may go through several tomographic studies throughout a period of time originating volumetric sets of image data that must be appropriately registered in order to track suspicious radiological findings. The structures or regions of interest may change their position or shape in CT exams acquired at different moments, due to postural, physiologic or pathologic changes, so, the exams should be registered before any follow-up information can be extracted. Postural mismatching throughout time is practically impossible to avoid being particularly evident when imaging is performed at the limiting spatial resolution. In this paper, we propose a method for intra-patient registration of pulmonary CT studies, to assist in the management of the oncological pathology. Our method takes advantage of prior segmentation work. In the first step, the pulmonary segmentation is performed where trachea and main bronchi are identified. Then, the registration method proceeds with a longitudinal alignment based on morphological features of the lungs, such as the position of the carina, the pulmonary areas, the centers of mass and the pulmonary trans-axial principal axis. The final step corresponds to the trans-axial registration of the corresponding pulmonary masked regions. This is accomplished by a pairwise sectional registration process driven by an iterative search of the affine transformation parameters leading to optimal similarity metrics. Results with several cases of intra-patient, intra-modality registration, up to 7 time points, show that this method provides accurate registration which is needed for quantitative tracking of lesions and the development of image fusion strategies that may effectively assist the follow-up process.

  8. Volumetric optoacoustic monitoring of endovenous laser treatments

    Science.gov (United States)

    Fehm, Thomas F.; Deán-Ben, Xosé L.; Schaur, Peter; Sroka, Ronald; Razansky, Daniel

    2016-03-01

    Chronic venous insufficiency (CVI) is one of the most common medical conditions with reported prevalence estimates as high as 30% in the adult population. Although conservative management with compression therapy may improve the symptoms associated with CVI, healing often demands invasive procedures. Besides established surgical methods like vein stripping or bypassing, endovenous laser therapy (ELT) emerged as a promising novel treatment option during the last 15 years offering multiple advantages such as less pain and faster recovery. Much of the treatment success hereby depends on monitoring of the treatment progression using clinical imaging modalities such as Doppler ultrasound. The latter however do not provide sufficient contrast, spatial resolution and three-dimensional imaging capacity which is necessary for accurate online lesion assessment during treatment. As a consequence, incidence of recanalization, lack of vessel occlusion and collateral damage remains highly variable among patients. In this study, we examined the capacity of volumetric optoacoustic tomography (VOT) for real-time monitoring of ELT using an ex-vivo ox foot model. ELT was performed on subcutaneous veins while optoacoustic signals were acquired and reconstructed in real-time and at a spatial resolution in the order of 200μm. VOT images showed spatio-temporal maps of the lesion progression, characteristics of the vessel wall, and position of the ablation fiber's tip during the pull back. It was also possible to correlate the images with the temperature elevation measured in the area adjacent to the ablation spot. We conclude that VOT is a promising tool for providing online feedback during endovenous laser therapy.

  9. Treatment planning for volumetric modulated arc therapy

    Energy Technology Data Exchange (ETDEWEB)

    Bedford, James L. [Joint Department of Physics, Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT (United Kingdom)

    2009-11-15

    Purpose: Volumetric modulated arc therapy (VMAT) is a specific type of intensity-modulated radiation therapy (IMRT) in which the gantry speed, multileaf collimator (MLC) leaf position, and dose rate vary continuously during delivery. A treatment planning system for VMAT is presented. Methods: Arc control points are created uniformly throughout one or more arcs. An iterative least-squares algorithm is used to generate a fluence profile at every control point. The control points are then grouped and all of the control points in a given group are used to approximate the fluence profiles. A direct-aperture optimization is then used to improve the solution, taking into account the allowed range of leaf motion of the MLC. Dose is calculated using a fast convolution algorithm and the motion between control points is approximated by 100 interpolated dose calculation points. The method has been applied to five cases, consisting of lung, rectum, prostate and seminal vesicles, prostate and pelvic lymph nodes, and head and neck. The resulting plans have been compared with segmental (step-and-shoot) IMRT and delivered and verified on an Elekta Synergy to ensure practicality. Results: For the lung, prostate and seminal vesicles, and rectum cases, VMAT provides a plan of similar quality to segmental IMRT but with faster delivery by up to a factor of 4. For the prostate and pelvic nodes and head-and-neck cases, the critical structure doses are reduced with VMAT, both of these cases having a longer delivery time than IMRT. The plans in general verify successfully, although the agreement between planned and measured doses is not very close for the more complex cases, particularly the head-and-neck case. Conclusions: Depending upon the emphasis in the treatment planning, VMAT provides treatment plans which are higher in quality and/or faster to deliver than IMRT. The scheme described has been successfully introduced into clinical use.

  10. Visualization and volumetric structures from MR images of the brain

    Energy Technology Data Exchange (ETDEWEB)

    Parvin, B.; Johnston, W.; Robertson, D.

    1994-03-01

    Pinta is a system for segmentation and visualization of anatomical structures obtained from serial sections reconstructed from magnetic resonance imaging. The system approaches the segmentation problem by assigning each volumetric region to an anatomical structure. This is accomplished by satisfying constraints at the pixel level, slice level, and volumetric level. Each slice is represented by an attributed graph, where nodes correspond to regions and links correspond to the relations between regions. These regions are obtained by grouping pixels based on similarity and proximity. The slice level attributed graphs are then coerced to form a volumetric attributed graph, where volumetric consistency can be verified. The main novelty of our approach is in the use of the volumetric graph to ensure consistency from symbolic representations obtained from individual slices. In this fashion, the system allows errors to be made at the slice level, yet removes them when the volumetric consistency cannot be verified. Once the segmentation is complete, the 3D surfaces of the brain can be constructed and visualized.

  11. Soft bilateral filtering volumetric shadows using cube shadow maps

    Science.gov (United States)

    Ali, Hatam H.; Sunar, Mohd Shahrizal; Kolivand, Hoshang

    2017-01-01

    Volumetric shadows often increase the realism of rendered scenes in computer graphics. Typical volumetric shadows techniques do not provide a smooth transition effect in real-time with conservation on crispness of boundaries. This research presents a new technique for generating high quality volumetric shadows by sampling and interpolation. Contrary to conventional ray marching method, which requires extensive time, this proposed technique adopts downsampling in calculating ray marching. Furthermore, light scattering is computed in High Dynamic Range buffer to generate tone mapping. The bilateral interpolation is used along a view rays to smooth transition of volumetric shadows with respect to preserving-edges. In addition, this technique applied a cube shadow map to create multiple shadows. The contribution of this technique isreducing the number of sample points in evaluating light scattering and then introducing bilateral interpolation to improve volumetric shadows. This contribution is done by removing the inherent deficiencies significantly in shadow maps. This technique allows obtaining soft marvelous volumetric shadows, having a good performance and high quality, which show its potential for interactive applications. PMID:28632740

  12. Determining Methane Leak Locations and Rates with a Wireless Network Composed of Low-Cost, Printed Sensors

    Science.gov (United States)

    Smith, C. J.; Kim, B.; Zhang, Y.; Ng, T. N.; Beck, V.; Ganguli, A.; Saha, B.; Daniel, G.; Lee, J.; Whiting, G.; Meyyappan, M.; Schwartz, D. E.

    2015-12-01

    We will present our progress on the development of a wireless sensor network that will determine the source and rate of detected methane leaks. The targeted leak detection threshold is 2 g/min with a rate estimation error of 20% and localization error of 1 m within an outdoor area of 100 m2. The network itself is composed of low-cost, high-performance sensor nodes based on printed nanomaterials with expected sensitivity below 1 ppmv methane. High sensitivity to methane is achieved by modifying high surface-area-to-volume-ratio single-walled carbon nanotubes (SWNTs) with materials that adsorb methane molecules. Because the modified SWNTs are not perfectly selective to methane, the sensor nodes contain arrays of variously-modified SWNTs to build diversity of response towards gases with adsorption affinity. Methane selectivity is achieved through advanced pattern-matching algorithms of the array's ensemble response. The system is low power and designed to operate for a year on a single small battery. The SWNT sensing elements consume only microwatts. The largest power consumer is the wireless communication, which provides robust, real-time measurement data. Methane leak localization and rate estimation will be performed by machine-learning algorithms built with the aid of computational fluid dynamics simulations of gas plume formation. This sensor system can be broadly applied at gas wells, distribution systems, refineries, and other downstream facilities. It also can be utilized for industrial and residential safety applications, and adapted to other gases and gas combinations.

  13. Bile Duct Leaks from the Intrahepatic Biliary Tree: A Review of Its Etiology, Incidence, and Management

    Directory of Open Access Journals (Sweden)

    Sorabh Kapoor

    2012-01-01

    Full Text Available Bile leaks from the intrahepatic biliary tree are an important cause of morbidity following hepatic surgery and trauma. Despite reduction in mortality for hepatic surgery in the last 2 decades, bile leaks rates have not changed significantly. In addition to posted operative bile leaks, leaks may occur following drainage of liver abscess and tumor ablation. Most bile leaks from the intrahepatic biliary tree are transient and managed conservatively by drainage alone or endoscopic biliary decompression. Selected cases may require reoperation and enteric drainage or liver resection for management.

  14. Massive Cerebrospinal Fluid Leak of the Temporal Bone

    Directory of Open Access Journals (Sweden)

    Giannicola Iannella

    2016-01-01

    Full Text Available 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.

  15. MCO combustible gas management leak test acceptance criteria

    Energy Technology Data Exchange (ETDEWEB)

    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).

  16. Leak test of the charcoal filter in the nuclear facility

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Sang Yeol; Lee, Key Soon; Hong, Kwon Pyo; Oh, Yon Woo; Park, Dae Kyu; Ahn, Sang Bok; Choo, Yong Sun; Kim, Sung Jung

    1998-06-01

    In the heating, ventilation and air conditioning(HVAC) system, pre-filter, HEPA(high efficiency particle air) filter and charcoal filter are instrumented in order to filter off the radioactive substance in the nuclear facility. Equipment of the charcoal filter off the radioactive substance in the nuclear facility. Equipment of the charcoal filter at the hot cell where manipulates the nuclear fuel irradiated in the nuclear reactor is essential for shutting off the leakage of the radioiodine which is produced from the cutting procedures of nuclear fuel. Also, the leak test of installed filter should be performed perfectly. In addition, charcoal filter is instrumented to filter the radioactive gas such as radioiodine which is produced in the nuclear facility. In this technical report, the theoretical discussion, the experimental procedures and the precautions of the leak test of charcoal filter are described. (author). 8 refs., 4 tabs., 8 figs.

  17. VOLUMETRIC ERROR COMPENSATION IN FIVE-AXIS CNC MACHINING CENTER THROUGH KINEMATICS MODELING OF GEOMETRIC ERROR

    Directory of Open Access Journals (Sweden)

    Pooyan Vahidi Pashsaki

    2016-06-01

    Full Text Available Accuracy of a five-axis CNC machine tool is affected by a vast number of error sources. This paper investigates volumetric error modeling and its compensation to the basis for creation of new tool path for improvement of work pieces accuracy. The volumetric error model of a five-axis machine tool with the configuration RTTTR (tilting head B-axis and rotary table in work piece side A΄ was set up taking into consideration rigid body kinematics and homogeneous transformation matrix, in which 43 error components are included. Volumetric error comprises 43 error components that can separately reduce geometrical and dimensional accuracy of work pieces. The machining accuracy of work piece is guaranteed due to the position of the cutting tool center point (TCP relative to the work piece. The cutting tool is deviated from its ideal position relative to the work piece and machining error is experienced. For compensation process detection of the present tool path and analysis of the RTTTR five-axis CNC machine tools geometrical error, translating current position of component to compensated positions using the Kinematics error model, converting newly created component to new tool paths using the compensation algorithms and finally editing old G-codes using G-code generator algorithm have been employed.

  18. Pathogenesis of vascular leak in dengue virus infection.

    Science.gov (United States)

    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.

  19. NSRD-10: Leak Path Factor Guidance Using MELCOR

    Energy Technology Data Exchange (ETDEWEB)

    Louie, David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Humphries, Larry L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-03-01

    Estimates of the source term from a U.S. Department of Energy (DOE) nuclear facility requires that the analysts know how to apply the simulation tools used, such as the MELCOR code, particularly for a complicated facility that may include an air ventilation system and other active systems that can influence the environmental pathway of the materials released. DOE has designated MELCOR 1.8.5, an unsupported version, as a DOE ToolBox code in its Central Registry, which includes a leak-path-factor guidance report written in 2004 that did not include experimental validation data. To continue to use this MELCOR version requires additional verification and validations, which may not be feasible from a project cost standpoint. Instead, the recent MELCOR should be used. Without any developer support and lack of experimental data validation, it is difficult to convince regulators that the calculated source term from the DOE facility is accurate and defensible. This research replaces the obsolete version in the 2004 DOE leak path factor guidance report by using MELCOR 2.1 (the latest version of MELCOR with continuing modeling development and user support) and by including applicable experimental data from the reactor safety arena and from applicable experimental data used in the DOE-HDBK-3010. This research provides best practice values used in MELCOR 2.1 specifically for the leak path determination. With these enhancements, the revised leak-path-guidance report should provide confidence to the DOE safety analyst who would be using MELCOR as a source-term determination tool for mitigated accident evaluations.

  20. Using Optical Plume Velocimetry to Estimate the Volume of Oil Released From the 2010 Gulf of Mexico Leak

    Science.gov (United States)

    Crone, T. J.; Tolstoy, M.

    2010-12-01

    To fully understand the environmental and ecological impacts of this disaster, an accurate estimate of the total oil released is required. We use optical plume velocimetry (OPV) to estimate the velocity of fluids issuing from the damaged well before and after the collapsed riser pipe was removed, and then estimate the volumetric flow rate under a range of assumptions. OPV was developed for measuring flow rates of fluids exiting black smoker hydrothermal vents on the deep sea floor (Crone et al., 2008). Black smoker vents produce a type of flow known as a turbulent buoyant jet and the Gulf of Mexico leak was a flow of the same class. Traditional optical fluid flow measurements use spatial cross-correlation methods that have been shown to underestimate flow rates when applied to turbulent buoyant jets. OPV uses interpolated temporal cross-correlation functions of image intensity across the entire region of interest to estimate image velocity. There are several potential sources of uncertainty in these calculations which may include errors associated with the estimation of the spatial resolution of the imagery, the image velocity field, the shear layer correction factor, and the area over which fluid is flowing, as well as uncertainty regarding the liquid oil fraction and temporal variability. We will describe in detail the effects of these uncertainties on the volume calculation. Using a liquid oil fraction of 0.4, we estimate the average flow rate from April 22nd to June 3rd , before the riser was removed, to be 55.9 x 103 barrels of oil per day (+/- 21%), excluding secondary leaks. After the riser was removed the total flow was 67.5 x 103 barrels/day (+/- 19%). Taking into account the oil collected by BP at the well head, our preliminary estimate of the total oil released is 4.37 x 106 barrels. (+/- 20%).

  1. Pleuroperitoneal Leak Complicating Peritoneal Dialysis: A Case Series

    Directory of Open Access Journals (Sweden)

    C. Kennedy

    2011-01-01

    Full Text Available Pressure related complications such as abdominal wall hernias occur with relative frequency in patients on peritoneal dialysis. Less frequently, a transudative pleural effusion containing dialysate can develop. This phenomenon appears to be due to increased intra-abdominal pressure in the setting of congenital or acquired diaphragmatic defects. We report three cases of pleuroperitoneal leak that occurred within a nine-month period at our institution. We review the literature on this topic, and discuss management options. The pleural effusion resolved in one patient following drainage of the peritoneum and a switch to haemodialysis. One patient required emergency thoracocentesis. The third patient developed a complex effusion requiring surgical intervention. The three cases highlight the variability of this condition in terms of timing, symptoms and management. The diagnosis of a pleuroperitoneal leak is an important one as it is managed very differently to most transudative pleural effusions seen in this patient population. Surgical repair may be necessary in those patients who wish to resume peritoneal dialysis, or in those patients with complex effusions. Pleuroperitoneal leak should be considered in the differential diagnosis of a pleural effusion, particularly a right-sided effusion, in a patient on peritoneal dialysis.

  2. Pleuroperitoneal leak complicating peritoneal dialysis: a case series.

    LENUS (Irish Health Repository)

    Kennedy, C

    2012-02-01

    Pressure related complications such as abdominal wall hernias occur with relative frequency in patients on peritoneal dialysis. Less frequently, a transudative pleural effusion containing dialysate can develop. This phenomenon appears to be due to increased intra-abdominal pressure in the setting of congenital or acquired diaphragmatic defects. We report three cases of pleuroperitoneal leak that occurred within a nine-month period at our institution. We review the literature on this topic, and discuss management options. The pleural effusion resolved in one patient following drainage of the peritoneum and a switch to haemodialysis. One patient required emergency thoracocentesis. The third patient developed a complex effusion requiring surgical intervention. The three cases highlight the variability of this condition in terms of timing, symptoms and management. The diagnosis of a pleuroperitoneal leak is an important one as it is managed very differently to most transudative pleural effusions seen in this patient population. Surgical repair may be necessary in those patients who wish to resume peritoneal dialysis, or in those patients with complex effusions. Pleuroperitoneal leak should be considered in the differential diagnosis of a pleural effusion, particularly a right-sided effusion, in a patient on peritoneal dialysis.

  3. Proceedings of the seminar on leak before break in reactor piping and vessels

    Energy Technology Data Exchange (ETDEWEB)

    Faidy, C. [ed.] [Electricite de France, Villeurbanne (France); Gilles, P. [ed.] [Framatome, Paris (France)

    1997-04-01

    The objective of the seminar was to present the current state of the art in Leak-Before-Break (LBB) methodology development, validation, and application in an international forum. With particular emphasis on industrial applications and regulatory policies, the seminar provided an opportunity to compare approaches, experiences, and codifications developed by different countries. The seminar was organized into four topic areas: status of LBB applications; technical issues in LBB methodology; complementary requirements (leak detection and inspection); LBB assessment and margins. As a result of this seminar, an improved understanding of LBB gained through sharing of different viewpoints from different countries, permits consideration of: simplified pipe support design and possible elimination of loss-of-coolant-accident (LOCA) mechanical consequences for specific cases; defense-in-depth type of applications without support modifications; support of safety cases for plants designed without the LOCA hypothesis. In support of these activities, better estimates of the limits to the LBB approach should follow, as well as an improvement in codifying methodologies. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  4. Multicenter assessment of the reproducibility of volumetric radiofrequency-based intravascular ultrasound measurements in coronary lesions that were consecutively stented

    DEFF Research Database (Denmark)

    Huisman, Jennifer; Egede, Rasmus; Rdzanek, Adam

    2012-01-01

    To assess in a multicenter design the between-center reproducibility of volumetric virtual histology intravascular ultrasound (VH-IVUS) measurements with a semi-automated, computer-assisted contour detection system in coronary lesions that were consecutively stented. To evaluate the reproducibili...... on average the highest measurement reproducibility. A central analysis for VH-IVUS multicenter studies of lesions prior to PCI should be pursued. Moreover, it may be problematical to pool VH-IVUS data of individual trials analyzed by independent centers.......To assess in a multicenter design the between-center reproducibility of volumetric virtual histology intravascular ultrasound (VH-IVUS) measurements with a semi-automated, computer-assisted contour detection system in coronary lesions that were consecutively stented. To evaluate the reproducibility...... of volumetric VH-IVUS measurements, experienced analysts of 4 European IVUS centers performed independent analyses (in total 8,052 cross-sectional analyses) to obtain volumetric data of 40 coronary segments (length 20.0 ± 0.3 mm) from target lesions prior to percutaneous intervention that were performed...

  5. 填埋场渗漏检测高压直流电法两种模型的比较%Comparison of two theoretical models for electric leak location at landfill

    Institute of Scientific and Technical Information of China (English)

    杨萍; 能昌信; 杨公训; 董路; 王琪; 王彦文

    2007-01-01

    To solve the disability of conventional model used in electrical leak location when measurement electrodes were buried under the liner,a new model of high voltage DC leak detection is developed.For single-liner landfill,the waste material layer,the geomembrane liner and the soil under the liner are simulated with infinite horizontal layers.The leak is regarded as two parts,one being negative current source at the entrance,and the other positive current source of the same size at the exit.Comparisons between the new theoretical model and conventional model show that conventional model is efficient in locating leaks in geomembane liner associating the dipole scanning above the liner but is ineffective when the measurement electrodes were buried under the liner.The new theoretical model data are in excellent agreement with experimental data not only above the liner but also under the finer.

  6. Improved volumetric imaging in tomosynthesis using combined multiaxial sweeps.

    Science.gov (United States)

    Gersh, Jacob A; Wiant, David B; Best, Ryan C M; Bennett, Marcus C; Munley, Michael T; King, June D; McKee, Mahta M; Baydush, Alan H

    2010-09-03

    This study explores the volumetric reconstruction fidelity attainable using tomosynthesis with a kV imaging system which has a unique ability to rotate isocentrically and with multiple degrees of mechanical freedom. More specifically, we seek to investigate volumetric reconstructions by combining multiple limited-angle rotational image acquisition sweeps. By comparing these reconstructed images with those of a CBCT reconstruction, we can gauge the volumetric fidelity of the reconstructions. In surgical situations, the described tomosynthesis-based system could provide high-quality volumetric imaging without requiring patient motion, even with rotational limitations present. Projections were acquired using the Digital Integrated Brachytherapy Unit, or IBU-D. A phantom was used which contained several spherical objects of varying contrast. Using image projections acquired during isocentric sweeps around the phantom, reconstructions were performed by filtered backprojection. For each image acquisition sweep configuration, a contrasting sphere is analyzed using two metrics and compared to a gold standard CBCT reconstruction. Since the intersection of a reconstructed sphere and an imaging plane is ideally a circle with an eccentricity of zero, the first metric presented compares the effective eccentricity of intersections of reconstructed volumes and imaging planes. As another metric of volumetric reconstruction fidelity, the volume of one of the contrasting spheres was determined using manual contouring. By comparing these manually delineated volumes with a CBCT reconstruction, we can gauge the volumetric fidelity of reconstructions. The configuration which yielded the highest overall volumetric reconstruction fidelity, as determined by effective eccentricities and volumetric contouring, consisted of two orthogonally-offset 60° L-arm sweeps and a single C-arm sweep which shared a pivot point with one the L-arm sweeps. When compared to a similar configuration that

  7. Aspects of volumetric efficiency measurement for reciprocating engines

    Directory of Open Access Journals (Sweden)

    Pešić Radivoje B.

    2013-01-01

    Full Text Available The volumetric efficiency significantly influences engine output. Both design and dimensions of an intake and exhaust system have large impact on volumetric efficiency. Experimental equipment for measuring of airflow through the engine, which is placed in the intake system, may affect the results of measurements and distort the real picture of the impact of individual structural factors. This paper deals with the problems of experimental determination of intake airflow using orifice plates and the influence of orifice plate diameter on the results of the measurements. The problems of airflow measurements through a multi-process Otto/Diesel engine were analyzed. An original method for determining volumetric efficiency was developed based on in-cylinder pressure measurement during motored operation, and appropriate calibration of the experimental procedure was performed. Good correlation between the results of application of the original method for determination of volumetric efficiency and the results of theoretical model used in research of influence of the intake pipe length on volumetric efficiency was determined. [Acknowledgments. The paper is the result of the research within the project TR 35041 financed by the Ministry of Science and Technological Development of the Republic of Serbia

  8. Research overview of real-time monitoring system for micro leak of three-dimensional pipe network

    Directory of Open Access Journals (Sweden)

    Shaofeng WANG

    2016-04-01

    Full Text Available Aiming at the key technical problems encountered by domestic and foreign scholars in building the real-time monitoring system for the micro leak of three-dimensional pipe networks, the paper classifies the problems into three aspects: 1 in the extraction of fault signal frequency, how to avoid the effect of the mixed echo stack and improve the delay estimation accuracy of the correlation; 2 in network bifurcation structure, how to discern the signal propagation path, and how to locate the leak source; 3 under the uncertainly delay in transmitting and receiving information data, how to ensure the time synchronization accuracy of the real-time monitoring system for the three-dimensional pipe network leakage. Through the comparison of the monitoring technologies for the pipe network leakage at home and abroad, it shows that the acoustic emission sensor network based three-dimensional pipeline leak real-time monitoring has great advantages in detecting the weak leakage of flammable and explosive gas/liquid transportation pipelines.

  9. A high volume, high throughput volumetric sorption analyzer

    Science.gov (United States)

    Soo, Y. C.; Beckner, M.; Romanos, J.; Wexler, C.; Pfeifer, P.; Buckley, P.; Clement, J.

    2011-03-01

    In this talk we will present an overview of our new Hydrogen Test Fixture (HTF) constructed by the Midwest Research Institute for The Alliance for Collaborative Research in Alternative Fuel Technology to test activated carbon monoliths for hydrogen gas storage. The HTF is an automated, computer-controlled volumetric instrument for rapid screening and manipulation of monoliths under an inert atmosphere (to exclude degradation of carbon from exposure to oxygen). The HTF allows us to measure large quantity (up to 500 g) of sample in a 0.5 l test tank, making our results less sensitive to sample inhomogeneity. The HTF can measure isotherms at pressures ranging from 1 to 300 bar at room temperature. For comparison, other volumetric instruments such as Hiden Isochema's HTP-1 Volumetric Analyser can only measure carbon samples up to 150 mg at pressures up to 200 bar. Work supported by the US DOD Contract # N00164-08-C-GS37.

  10. Volumetric (3D) compressive sensing spectral domain optical coherence tomography.

    Science.gov (United States)

    Xu, Daguang; Huang, Yong; Kang, Jin U

    2014-11-01

    In this work, we proposed a novel three-dimensional compressive sensing (CS) approach for spectral domain optical coherence tomography (SD OCT) volumetric image acquisition and reconstruction. Instead of taking a spectral volume whose size is the same as that of the volumetric image, our method uses a sub set of the original spectral volume that is under-sampled in all three dimensions, which reduces the amount of spectral measurements to less than 20% of that required by the Shan-non/Nyquist theory. The 3D image is recovered from the under-sampled spectral data dimension-by-dimension using the proposed three-step CS reconstruction strategy. Experimental results show that our method can significantly reduce the sampling rate required for a volumetric SD OCT image while preserving the image quality.

  11. Optimal pressure sensor placement for leak localisation using a relaxed isolation index : application to the Barcelona water network

    OpenAIRE

    Cugueró Escofet, Miquel Àngel; Puig Cayuela, Vicenç; Quevedo Casín, Joseba Jokin; Blesa Izquierdo, Joaquim

    2015-01-01

    Water distribution networks are large complex systems that are affected by leaks, which often entail high costs and may severely jeopardize the overall water distribution performance. Successful leak localisation is paramount in order to minimize the impact of these leaks when occurring. Sensor placement is a key issue in the leak localisation process, since the overall performance and success of the leak isolation method highly depends on the choice of the sensors gathering data from the net...

  12. Multiple sparse volumetric priors for distributed EEG source reconstruction.

    Science.gov (United States)

    Strobbe, Gregor; van Mierlo, Pieter; De Vos, Maarten; Mijović, Bogdan; Hallez, Hans; Van Huffel, Sabine; López, José David; Vandenberghe, Stefaan

    2014-10-15

    We revisit the multiple sparse priors (MSP) algorithm implemented in the statistical parametric mapping software (SPM) for distributed EEG source reconstruction (Friston et al., 2008). In the present implementation, multiple cortical patches are introduced as source priors based on a dipole source space restricted to a cortical surface mesh. In this note, we present a technique to construct volumetric cortical regions to introduce as source priors by restricting the dipole source space to a segmented gray matter layer and using a region growing approach. This extension allows to reconstruct brain structures besides the cortical surface and facilitates the use of more realistic volumetric head models including more layers, such as cerebrospinal fluid (CSF), compared to the standard 3-layered scalp-skull-brain head models. We illustrated the technique with ERP data and anatomical MR images in 12 subjects. Based on the segmented gray matter for each of the subjects, cortical regions were created and introduced as source priors for MSP-inversion assuming two types of head models. The standard 3-layered scalp-skull-brain head models and extended 4-layered head models including CSF. We compared these models with the current implementation by assessing the free energy corresponding with each of the reconstructions using Bayesian model selection for group studies. Strong evidence was found in favor of the volumetric MSP approach compared to the MSP approach based on cortical patches for both types of head models. Overall, the strongest evidence was found in favor of the volumetric MSP reconstructions based on the extended head models including CSF. These results were verified by comparing the reconstructed activity. The use of volumetric cortical regions as source priors is a useful complement to the present implementation as it allows to introduce more complex head models and volumetric source priors in future studies.

  13. Sperm volumetric dynamics during in vitro capacitation process in bovine spermatozoa.

    Science.gov (United States)

    García-Herreros, M; Leal, C L V

    2015-06-01

    Previous studies have demonstrated that sperm head morphometry can be used as a potential diagnostic tool for detecting biophysical changes associated with sperm viability in bovine spermatozoa. In this study, sperm head morphometry was used to investigate its value as a biophysical marker for detecting volumetric changes in bovine spermatozoa under in vitro capacitating and non-capacitating incubation conditions. To further test this hypotesis, aliquots of pooled, washed bovine sperm were incubated in either Tyrode's complete medium with heparin (TCMH; a capacitating medium containing Ca2+, NaHCO3 and heparin), Tyrode's complete medium heparin-free (TCM; a medium containing just Ca2+ and NaHCO3) or Tyrode's basal medium (TBM; a non-capacitating medium free of Ca2+, NaHCO3 and heparin, used as control). Aliquots of sperm were processed for morphometric analysis at different incubation-time intervals (0, 3 and 6 h at 38°C), and the chlortetracycline assay was used simultaneously to confirm the ability of the sperm to undergo capacitation (B pattern) and the acrosome reaction (AR pattern) status in each medium. After 3 h of incubation under TCMH conditions, a significant increase was observed in the percentage of B and AR patterns and a significant decrease was found in all sperm morphometric parameters (Psperm size and AR pattern (r=-0.875, Psperm head morphometry can be used as a potential biophysical marker for detecting volumetric changes during capacitation process in bovine spermatozoa.

  14. Isolation and characterization of gasoline-degrading bacteria from gas station leaking-contaminated soils

    Institute of Scientific and Technical Information of China (English)

    LU Si-jin; WANG Hong-qi; YAO Zhi-hua

    2006-01-01

    The effects of culture conditions in vitro and biosurfactant detection were studied on bacterial strains capable of degrading gasoline from contaminated soils near gas station. The main results were summarized as follows. Three bacteria (strains Q10, Q14 and Q18) that were considered as efficiently degrading strains were isolated and identified as Pseudomonas sp., Flavobacterium sp. and Rhodococcus sp., respectively. The optimal growth conditions of three bacteria including pH, temperature and the concentration of gasoline were similar. The reduction in surface tension was observed with all the three bacteria, indicating the production of toluene, ethylbenzene and xylene (BTEX) could easily be degraded by the three isolates. The consortium was more effective than the individual cultures in degrading added gasoline, diesel oil, and BTEX. These results indicate that these strains have great potential for in situ remediation of soils contaminated by gas station leaking.

  15. Volumetric measurements of a spatially growing dust acoustic wave

    Science.gov (United States)

    Williams, Jeremiah D.

    2012-11-01

    In this study, tomographic particle image velocimetry (tomo-PIV) techniques are used to make volumetric measurements of the dust acoustic wave (DAW) in a weakly coupled dusty plasma system in an argon, dc glow discharge plasma. These tomo-PIV measurements provide the first instantaneous volumetric measurement of a naturally occurring propagating DAW. These measurements reveal over the measured volume that the measured wave mode propagates in all three spatial dimensional and exhibits the same spatial growth rate and wavelength in each spatial direction.

  16. Volumetric measurements of a spatially growing dust acoustic wave

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Jeremiah D. [Physics Department, Wittenberg University, Springfield, Ohio 45504 (United States)

    2012-11-15

    In this study, tomographic particle image velocimetry (tomo-PIV) techniques are used to make volumetric measurements of the dust acoustic wave (DAW) in a weakly coupled dusty plasma system in an argon, dc glow discharge plasma. These tomo-PIV measurements provide the first instantaneous volumetric measurement of a naturally occurring propagating DAW. These measurements reveal over the measured volume that the measured wave mode propagates in all three spatial dimensional and exhibits the same spatial growth rate and wavelength in each spatial direction.

  17. Volumetric Pricing of Agricultural Water Supplies: A Case Study

    Science.gov (United States)

    Griffin, Ronald C.; Perry, Gregory M.

    1985-07-01

    Models of water consumption by rice producers are conceptualized and then estimated using cross-sectional time series data obtained from 16 Texas canal operators for the years 1977-1982. Two alternative econometric models demonstrate that both volumetric and flat rate water charges are strongly and inversely related to agricultural water consumption. Nonprice conservation incentives accompanying flat rates are hypothesized to explain the negative correlation of flat rate charges and water consumption. Application of these results suggests that water supply organizations in the sample population converting to volumetric pricing will generally reduce water consumption.

  18. Normally-Closed Zero-Leak Valve with Magnetostrictive Actuator

    Science.gov (United States)

    Ramspacher, Daniel J. (Inventor); Richard, James A. (Inventor)

    2017-01-01

    A non-pyrotechnic, normally-closed, zero-leak valve is a replacement for the pyrovalve used for both in-space and launch vehicle applications. The valve utilizes a magnetostrictive alloy for actuation, rather than pyrotechnic charges. The alloy, such as Terfenol-D, experiences magnetostriction, i.e. a gross elongation, when exposed to a magnetic field. This elongation fractures a parent metal seal, allowing fluid flow through the valve. The required magnetic field is generated by redundant coils that are isolated from the working fluid.

  19. Bottom-Fill Method for Stopping Leaking Oil Wells

    CERN Document Server

    Bloomfield, Louis A

    2010-01-01

    Hardware failure at the top of a deep underwater oil well can result in a catastrophic oil leak. The enormous pressure lifting the column of oil in that well makes it nearly impossible to stop from the top with seals or pressurization. We propose to fill the bottom of the well with dense and possibly streamlined objects that can descend through the rising oil. As they accumulate, those objects couple to the oil via viscous and drag forces and increase the oil's effective density. When its effective density exceeds that of the earth's crust, the oil will have essentially stopped flowing.

  20. Tracking artificial sweeteners and pharmaceuticals introduced into urban groundwater by leaking sewer networks.

    Science.gov (United States)

    Wolf, Leif; Zwiener, Christian; Zemann, Moritz

    2012-07-15

    There is little quantitative information on the temporal trends of pharmaceuticals and other emerging compounds, including artificial sweeteners, in urban groundwater and their suitability as tracers to inform urban water management. In this study, pharmaceuticals and artificial sweeteners were monitored over 6 years in a shallow urban groundwater body along with a range of conventional sewage tracers in a network of observation wells that were specifically constructed to assess sewer leakage. Out of the 71 substances screened, 24 were detected at above the analytical detection limit. The most frequent compounds were the iodinated X-ray contrast medium amidotrizoic acid (35.3%), the anticonvulsant carbamazepine (33.3%) and the artificial sweetener acesulfame (27.5%), while all other substances occurred in less than 10% of the screened wells. The results from the group of specifically constructed focus wells within 10 m of defective sewers confirmed sewer leaks as being a major entrance pathway into the groundwater. The spatial distribution of pharmaceuticals and artificial sweeteners corresponds well with predictions by pipeline leakage models, which operate on optical sewer condition monitoring data and hydraulic information. Correlations between the concentrations of carbamazepine, iodinated X-ray contrast media and artificial sweeteners were weak to non-existent. Peak concentrations of up to 4130 ng/l of amidotrizoic acid were found in the groundwater downstream of the local hospital. The analysis of 168 samples for amidotrizoic acid, taken at 5 different occasions, did not show significant temporal trends for the years 2002-2008, despite changed recommendations in the medical usage of amidotrizoic acid. The detailed results show that the current mass balance approaches for urban groundwater bodies must be adapted to reflect the spatially distributed leaks and the variable wastewater composition in addition to the lateral and horizontal groundwater fluxes.

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

    Energy Technology Data Exchange (ETDEWEB)

    Girardot, Crystal L.; Harlow, Donald G.

    2013-12-02

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Girardot, Crystal L.; Harlow, Donald G.

    2013-09-10

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

  3. Chyle leak following right axillary lymph node dissection: A case report and review of current literature

    Directory of Open Access Journals (Sweden)

    J.D. Daggett

    2016-01-01

    Full Text Available This report discusses the case of a chyle leak following a right axillary lymph node dissection for breast cancer. This presented as a sudden change in drainage character from a right axillary surgical drain from serous to milky white shortly after restarting a diet. The diagnosis of chyle leak was confirmed by laboratory testing of the fluid and managed with closed suction drainage. Chyle leak is a rare, but increasingly recognized complication following axillary clearance for breast cancer and melanoma.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-22

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

  5. A simplified approach for assessing the leak-before-break for the flawed pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, P. [Ramagundam Super Thermal Power Station, NTPC Ltd, Jyothinagar 505215 (India); Amirthagadeswaran, K.S. [Faculty of Mechanical Engineering, Government College of Technology, Coimbatore 641013 (India); Christopher, T. [Faculty of Mechanical Engineering, Government College of Engineering, Tirunelveli 627007 (India); Nageswara Rao, B., E-mail: bnrao52@rediffmail.com [Faculty of Mechanical Engineering, School of Mechanical and Civil Sciences, K L University, Green Fields, Vaddeswaram, Guntur 522502 (India)

    2016-06-15

    Surface cracks or embedded cracks in pressure vessels under service may grow and form stable through-thickness cracks causing leak prior to failure. If this leak-before-break phenomenon takes place, then there is a possibility of preventing the vessel failure. This paper presents a simplified approach for assessing the leak-before-break or failure of the flawed pressure vessels. This approach is validated through comparison of existing test data.

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

    Energy Technology Data Exchange (ETDEWEB)

    Girardot, Crystal L.; Harlow, Donald G.

    2014-05-15

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

  7. Comprehensive Leakproof Measures for Pancreaticoduodenectomy:A Report of 128 Consecutive Operations Without Pancreatic Leak

    Institute of Scientific and Technical Information of China (English)

    LIHan-Xian

    2003-01-01

    MeSHpancreaticoduodenectomy;pancreatic anastomotic leak; fistula of pancreas;periampullary carcinoma; jaundice complicationcarcinoma of pancreas;ABSTRACY Object To prevent pancreatic anastomotic leak by the comprehensive leakproof measures for pancre-aticoduodenectomy. Methods From December 1981 to June 2002, 128 consecutive patients underwent pancreati-coduodenectomy. 127 cases suffered from the malignant disease and one from chronic pancreatitis. The author performedthe operations and adopted the comprehensive measures to prevent pancreatic anastomotic leak. The measures were mainly

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

    Energy Technology Data Exchange (ETDEWEB)

    Girardot, Crystal L.; Harlow, Donald G.

    2013-07-30

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

  9. Transepithelial leak in Barrett's esophagus patients: The role of proton pump inhibitors

    Institute of Scientific and Technical Information of China (English)

    Christopher Farrell; James M Mullin; Melissa Morgan; Owen Tully; Kevin Wolov; Keith Kearney; Benjamin Ngo; Giancarlo Mercogliano,; James J Thornton; Mary Carmen Valenzano

    2012-01-01

    AIM:To determine if the observed paracellular sucrose leak in Barrett's esophagus patients is due to their proton pump inhibitor (PPI) use.METHODS:The in vivo sucrose permeability test was administered to healthy controls,to Barrett's patients and to non-Barrett's patients on continuous PPI therapy.Degree of leak was tested for correlation with presence of Barrett's,use of PPIs,and length of Barrett's segment and duration of PPI use.RESULTS:Barrett's patients manifested a near 3-fold greater,upper gastrointestinal sucrose leak than healthy controls.A decrease of sucrose leak was observed in Barrett's patients who ceased PPI use for 7 d.Although initial introduction of PPI use (in a PPI-nafve population) results in dramatic increase in sucrose leak,long-term,continuous PPI use manifested a slow spontaneous decline in leak.The sucrose leak observed in Barrett's patients showed no correlation to the amount of Barrett's tissue present in the esophagus.CONCLUSION:Although future research is needed to determine the degree of paracellular leak in actual Barrett's mucosa,the relatively high degree of leak observed with in vivo sucrose permeability measurement of Barrett's patients reflects their PPI use and not their Barrett's tissue per se.

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

    Energy Technology Data Exchange (ETDEWEB)

    Girardot, Crystal L.; Harlow, Donald G.

    2013-11-19

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

  11. A Cranial-Sided Approach for Repeated Mitral Periprosthetic Leak After Right Pneumonectomy.

    Science.gov (United States)

    Takahashi, Yosuke; Shibata, Toshihiko; Sasaki, Yasuyuki; Kato, Yasuyuki; Motoki, Manabu; Morisaki, Akimasa; Nishimura, Shinsuke; Hattori, Koji

    2016-03-01

    A 72-year-old man presented with worsening dyspnea on effort. He underwent right pneumonectomy 40 years ago, then mitral valve replacement through a right thoracotomy 8 years ago with repeat surgery to repair a periprosthetic valve leak; the mediastinum was displaced to the right, and the heart was rotated counterclockwise. Transthoracic echocardiography showed periprosthetic valve leak recurrence near the left atrial appendage. We repaired the periprosthetic valve leak through a median sternotomy. Transecting the main pulmonary artery allowed us to widely open the cranial-sided left atrium. We obtained good exposure of the mitral valve, and repaired the periprosthetic valve leak using pledgeted sutures and a pericardial patch.

  12. Oil spills and gas leaks: environmental response, prevention, and cost recovery

    National Research Council Canada - National Science Library

    Testa, Stephen M; Jacobs, James, A

    2013-01-01

    Oil Spills and Gas Leaks highlights the complex nature of petroleum hydrocarbon fuel extraction methods, the unintended consequences when disasters occur, spill behavior, and environmental impact mitigation...

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

    Science.gov (United States)

    Brody, Howard

    2014-03-01

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

  14. Non-linear leak currents affect mammalian neuron physiology

    Directory of Open Access Journals (Sweden)

    Shiwei eHuang

    2015-11-01

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

  15. Space-Time Transfinite Interpolation of Volumetric Material Properties.

    Science.gov (United States)

    Sanchez, Mathieu; Fryazinov, Oleg; Adzhiev, Valery; Comninos, Peter; Pasko, Alexander

    2015-02-01

    The paper presents a novel technique based on extension of a general mathematical method of transfinite interpolation to solve an actual problem in the context of a heterogeneous volume modelling area. It deals with time-dependent changes to the volumetric material properties (material density, colour, and others) as a transformation of the volumetric material distributions in space-time accompanying geometric shape transformations such as metamorphosis. The main idea is to represent the geometry of both objects by scalar fields with distance properties, to establish in a higher-dimensional space a time gap during which the geometric transformation takes place, and to use these scalar fields to apply the new space-time transfinite interpolation to volumetric material attributes within this time gap. The proposed solution is analytical in its nature, does not require heavy numerical computations and can be used in real-time applications. Applications of this technique also include texturing and displacement mapping of time-variant surfaces, and parametric design of volumetric microstructures.

  16. In Vivo Real Time Volumetric Synthetic Aperture Ultrasound Imaging

    DEFF Research Database (Denmark)

    Bouzari, Hamed; Rasmussen, Morten Fischer; Brandt, Andreas Hjelm;

    2015-01-01

    Synthetic aperture (SA) imaging can be used to achieve real-time volumetric ultrasound imaging using 2-D array transducers. The sensitivity of SA imaging is improved by maximizing the acoustic output, but one must consider the limitations of an ultrasound system, both technical and biological...

  17. Automatic segmentation of pulmonary segments from volumetric chest CT scans.

    NARCIS (Netherlands)

    Rikxoort, E.M. van; Hoop, B. de; Vorst, S. van de; Prokop, M.; Ginneken, B. van

    2009-01-01

    Automated extraction of pulmonary anatomy provides a foundation for computerized analysis of computed tomography (CT) scans of the chest. A completely automatic method is presented to segment the lungs, lobes and pulmonary segments from volumetric CT chest scans. The method starts with lung segmenta

  18. Volumetric T-spline Construction Using Boolean Operations

    Science.gov (United States)

    2013-07-01

    15213, USA 2 Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX 78712, USA 3 Department of Civil and...and S. Yau. Volumetric harmonic map. Communications in Information and Systems, 3(3):191–202, 2003. 12. C.A.R. Guerra . Simultaneous untangling and

  19. Volumetric motion quantification by 3D tissue phase mapped CMR

    Directory of Open Access Journals (Sweden)

    Lutz Anja

    2012-10-01

    Full Text Available Abstract Background The objective of this study was the quantification of myocardial motion from 3D tissue phase mapped (TPM CMR. Recent work on myocardial motion quantification by TPM has been focussed on multi-slice 2D acquisitions thus excluding motion information from large regions of the left ventricle. Volumetric motion assessment appears an important next step towards the understanding of the volumetric myocardial motion and hence may further improve diagnosis and treatments in patients with myocardial motion abnormalities. Methods Volumetric motion quantification of the complete left ventricle was performed in 12 healthy volunteers and two patients applying a black-blood 3D TPM sequence. The resulting motion field was analysed regarding motion pattern differences between apical and basal locations as well as for asynchronous motion pattern between different myocardial segments in one or more slices. Motion quantification included velocity, torsion, rotation angle and strain derived parameters. Results All investigated motion quantification parameters could be calculated from the 3D-TPM data. Parameters quantifying hypokinetic or asynchronous motion demonstrated differences between motion impaired and healthy myocardium. Conclusions 3D-TPM enables the gapless volumetric quantification of motion abnormalities of the left ventricle, which can be applied in future application as additional information to provide a more detailed analysis of the left ventricular function.

  20. Video-rate volumetric optical coherence tomography-based microangiography

    Science.gov (United States)

    Baran, Utku; Wei, Wei; Xu, Jingjiang; Qi, Xiaoli; Davis, Wyatt O.; Wang, Ruikang K.

    2016-04-01

    Video-rate volumetric optical coherence tomography (vOCT) is relatively young in the field of OCT imaging but has great potential in biomedical applications. Due to the recent development of the MHz range swept laser sources, vOCT has started to gain attention in the community. Here, we report the first in vivo video-rate volumetric OCT-based microangiography (vOMAG) system by integrating an 18-kHz resonant microelectromechanical system (MEMS) mirror with a 1.6-MHz FDML swept source operating at ˜1.3 μm wavelength. Because the MEMS scanner can offer an effective B-frame rate of 36 kHz, we are able to engineer vOMAG with a video rate up to 25 Hz. This system was utilized for real-time volumetric in vivo visualization of cerebral microvasculature in mice. Moreover, we monitored the blood perfusion dynamics during stimulation within mouse ear in vivo. We also discussed this system's limitations. Prospective MEMS-enabled OCT probes with a real-time volumetric functional imaging capability can have a significant impact on endoscopic imaging and image-guided surgery applications.