WorldWideScience

Sample records for leak detection techniques

  1. 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.

  2. 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.

  3. 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.

  4. 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)

  5. 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.

  6. 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....

  7. 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)

  8. 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.

  9. 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.[...

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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)

  18. 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...

  19. 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...

  20. 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...

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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)

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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...

  16. 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...

  17. 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...

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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).

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. [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.

  13. 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.

  14. 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.

  15. 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.

  16. Surgical Repair of Leaking Filtering Blebs Using Two Different Techniques

    Directory of Open Access Journals (Sweden)

    António B Melo

    2012-01-01

    Full Text Available Purpose: To report the outcomes of two different surgical techniques for the repair of late onset bleb leakage following trabeculectomy. Methods: This retrospective study includes 21 eyes of 20 patients with prior trabeculectomy and late-onset bleb leaks; 14 eyes underwent excision of the filtering bleb together with conjunctival advancement while in the other 7 eyes the bleb was retained but de-epithelialized before conjunctival advancement. Success was defined as resolution of leakage with no need for additional glaucoma surgery together with intraocular pressure (IOP of 5-21 mmHg. Complete and qualified success was considered when the above mentioned was achieved without or with glaucoma medications, respectively. Results: Mean duration of follow-up was 20.3΁14.4 months. No significant difference was observed between the two groups in terms of complete, qualified and overall success rates (P>0.05, however more antiglaucoma medications were necessary in the bleb excision group (P=0.02. Conclusions: Both surgical techniques of bleb repair were comparably effective, however the bleb de-epithelialization technique was associated with less need for glaucoma medications after the procedure.

  17. 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.

  18. 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)

  19. 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.

  20. 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.'

  1. 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.

  2. 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.

  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. 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

  6. 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.

  7. 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).

  8. 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)

  9. 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.

  10. 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)

  11. 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

  12. 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...

  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. Percutaneous Vertebroplasty: A New Serial Injection Technique to Minimize Cement Leak

    OpenAIRE

    2015-01-01

    Study Design This is a prospective cohort study. Purpose This study discusses a new technique for injecting cement in the affected vertebrae. Overview of Literature Since introduction of vertebroplasty to clinical practice, the cement leak is considered the most frequent and hazardous complication. In literature, the cement extravasation occurred in 26%-97% of the cases. Methods A hundred and twenty-three patients underwent vertebroplasty using the serial injection technique. The package of t...

  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. 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.

  10. 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.

  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. 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.

  14. 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.

  15. 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)

  16. 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.

  17. 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...

  18. 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.

  19. 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.

  20. 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)

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.)

  13. 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).

  14. 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)

  15. 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.

  16. 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)

  17. 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...

  18. 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.

  19. Exoplanet Detection Techniques

    CERN Document Server

    Fischer, Debra A; Laughlin, Greg P; Macintosh, Bruce; Mahadevan, Suvrath; Sahlmann, Johannes; Yee, Jennifer C

    2015-01-01

    We are still in the early days of exoplanet discovery. Astronomers are beginning to model the atmospheres and interiors of exoplanets and have developed a deeper understanding of processes of planet formation and evolution. However, we have yet to map out the full complexity of multi-planet architectures or to detect Earth analogues around nearby stars. Reaching these ambitious goals will require further improvements in instrumentation and new analysis tools. In this chapter, we provide an overview of five observational techniques that are currently employed in the detection of exoplanets: optical and IR Doppler measurements, transit photometry, direct imaging, microlensing, and astrometry. We provide a basic description of how each of these techniques works and discuss forefront developments that will result in new discoveries. We also highlight the observational limitations and synergies of each method and their connections to future space missions.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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)

  8. 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.

  9. 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...

  10. 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

  11. 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

  12. 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

  13. 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)

  14. Malware Detection and Removal Techniques

    Directory of Open Access Journals (Sweden)

    Sudhakar Singh

    2013-01-01

    Full Text Available Malwares are malignant softwares. It is designed to damage computer systems without the knowledge of the owner using the system. Softwares from reputable vendors also contain malicious code that affects the system or leaks informations to remote servers. Malwares includes computer viruses, Worms, spyware, dishonest ad-ware, rootkits, Trojans, dialers etc. Malware is one of the most serious security threats on the Internet today. In fact, most Internet problems such as spam e-mails and denial of service attacks have malwareas their underlying cause. Computers that are compromised with malware are often networked together to form botnets and many attacks are launched using these malicious, attacker controlled networks. The paper focuses on various Malware detection and removal methods.

  15. 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.

  16. GEOPHYSICAL TECHNIQUES IN DETECTION TO RIVER EMBANKMENTS

    Institute of Scientific and Technical Information of China (English)

    CHEN Chao; LIU Jian-ping; XU Shun-fang; XIA Jiang-hai

    2004-01-01

    Geophysical technologies are very effective in environmental, engineering and groundwater applications. Parameters of delineating nature of near-surface materials such as compressional-wave velocity, shear-wave velocity can be obtained using shallow seismic methods. Electric methods are primary approaches for investigating groundwater and detecting leakage. Both of the methods are applied to detect embankment in hope of obtaining evidence of the strength and moisture inside the body. A technological experiment has been done for detecting and discovering the hidden troubles in the embankment of Yangtze River,Songzi, Hubei, China in 2003. Surface-wave and DC multi-channel array resistivity sounding techniques were used to detect hidden trouble inside and under dike like pipe-seeps. This paper discusses the exploration strategy and the effect of geological characteristics. A practical approach of combining seismic and electric resistivity measurements was applied to locate potential pipe-seeps in embankment in the experiment. The method presents a potential leak factor based on the shear-wave velocity and the resistivity of the medium to evaluate anomalies. An anomaly found in a segment of embankment detected was verified, where occurred a pipe-seep during the 98′ flooding.

  17. 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.)

  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. 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.

  2. 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.

  3. 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.

  4. 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...

  5. 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...

  6. RADIOACTIVE OR NATURAL TRACER。TECHNIQUES FOR LEAK DETERMINING OF DAM ABUTMENT

    Institute of Scientific and Technical Information of China (English)

    陈建生; 杜国平; 等

    1995-01-01

    Infiltration and localization of preferential infiltration zones at the dam abutment are measured using radioactive tracer tests of flow in boreholes,meanwhile interconnection between boreholes and the energing water points is analysed.The theory and practice of radioactive tracer synthetic detective method are described to give methods and calculation formulae used under the condition of stable flow in single well to measure permeability coefficient and hydrostatic heads.Major single hole techniques including measurement for seepage line,velocity,rate of seepage flow and relationship of recharge of groundwater in aquifers are introduced briefly.The possibilities offered by natureal tracers are analysed,uincluding electric-conduct,pH-value and temperature of water as well as stable isotopes(D,18O) and tritium.Furthermore,the sensibilities of this theory and methods were confirmed by detecting seepage flow field of Xinanjiang Dam.

  7. Cell Phone Detection Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, Richard M.; Bunch, Kyle J.; Puzycki, David J.; Slaugh, Ryan W.; Good, Morris S.; McMakin, Douglas L.

    2007-10-01

    A team composed of Rick Pratt, Dave Puczyki, Kyle Bunch, Ryan Slaugh, Morris Good, and Doug McMakin teamed together to attempt to exploit cellular telephone features and detect if a person was carrying a cellular telephone into a Limited Area. The cell phone’s electromagnetic properties were measured, analyzed, and tested in over 10 different ways to determine if an exploitable signature exists. The method that appears to have the most potential for success without adding an external tag is to measure the RF spectrum, not in the cell phone band, but between 240 and 400MHz. Figures 1- 7 show the detected signal levels from cell phones from three different manufacturers.

  8. Nuclear material detection techniques

    Science.gov (United States)

    Christian, James F.; Sia, Radia; Dokhale, Purushottam; Shestakova, Irina; Nagarkar, Vivek; Shah, Kanai; Johnson, Erik B.; Stapels, Christopher J.; Ryan, James M.; Macri, John; Bravar, Ulisse; Leung, Ka-Ngo; Squillante, Michael R.

    2008-04-01

    Illicit nuclear materials represent a threat for the safety of the American citizens, and the detection and interdiction of a nuclear weapon is a national problem that has not been yet solved. Alleviating this threat represents an enormous challenge to current detection methods that have to be substantially improved to identify and discriminate threatening from benign incidents. Rugged, low-power and less-expensive radiation detectors and imagers are needed for large-scale wireless deployment. Detecting the gamma rays emitted by nuclear and fissionable materials, particularly special nuclear materials (SNM), is the most convenient way to identify and locate them. While there are detectors that have the necessary sensitivity, none are suitable to meet the present need, primarily because of the high occurrence of false alarms. The exploitation of neutron signatures represents a promising solution to detecting illicit nuclear materials. This work presents the development of several detector configurations such as a mobile active interrogation system based on a compact RF-Plasma neutron generator developed at LBNL and a fast neutron telescope that uses plastic scintillating-fibers developed at the University of New Hampshire. A human-portable improved Solid-State Neutron Detector (SSND) intended to replace pressurized 3He-tubes will be also presented. The SSND uses an ultra-compact CMOS-SSPM (Solid-State Photomultiplier) detector, developed at Radiation Monitoring devices Inc., coupled to a neutron sensitive scintillator. The detector is very fast and can provide time and spectroscopy information over a wide energy range including fast neutrons.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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...

  18. 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.

  19. 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.

  20. 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)

  1. 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)

  2. 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.

  3. 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.

  4. Discovering the Botnet Detection Techniques

    Science.gov (United States)

    Rahim, Aneel; Bin Muhaya, Fahad T.

    Botnet is a network of compromised computers. It just fellow the master slave concept. Bots are comprised computers and do the tasks what ever their master orders them. Internet Relay Chat (IRC) is used for the communication between the master and bots. Information is also encrypted to avoid the effect of third party. In this paper we discuss the Botnets detection techniques and comparative analysis of these techniques on the basis of DNS query, History data and group activity.

  5. 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

  6. 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.

  7. Historical Techniques of Lie Detection

    Directory of Open Access Journals (Sweden)

    Martina Vicianova

    2015-08-01

    Full Text Available Since time immemorial, lying has been a part of everyday life. For this reason, it has become a subject of interest in several disciplines, including psychology. The purpose of this article is to provide a general overview of the literature and thinking to date about the evolution of lie detection techniques. The first part explores ancient methods recorded circa 1000 B.C. (e.g., God’s judgment in Europe. The second part describes technical methods based on sciences such as phrenology, polygraph and graphology. This is followed by an outline of more modern-day approaches such as FACS (Facial Action Coding System, functional MRI, and Brain Fingerprinting. Finally, after the familiarization with the historical development of techniques for lie detection, we discuss the scope for new initiatives not only in the area of designing new methods, but also for the research into lie detection itself, such as its motives and regulatory issues related to deception.

  8. Leak testing of bubble-tight dampers using tracer gas techniques

    Energy Technology Data Exchange (ETDEWEB)

    Lagus, P.L. [Lagus Applied Technology, Inc., San Diego, CA (United States); DuBois, L.J. [Commonwealth Edison, Zion, IL (United States); Fleming, K.M. [NCS Corporation, Columbus, OH (United States)] [and others

    1995-02-01

    Recently tracer gas techniques have been applied to the problem of measuring the leakage across an installed bubble-tight damper. A significant advantage of using a tracer gas technique is that quantitative leakage data are obtained under actual operating differential pressure conditions. Another advantage is that leakage data can be obtained using relatively simple test setups that utilize inexpensive materials without the need to tear ducts apart, fabricate expensive blank-off plates, and install test connections. Also, a tracer gas technique can be used to provide an accurate field evaluation of the performance of installed bubble-tight dampers on a periodic basis. Actual leakage flowrates were obtained at Zion Generating Station on four installed bubble-tight dampers using a tracer gas technique. Measured leakage rates ranged from 0.01 CFM to 21 CFM. After adjustment and subsequent retesting, the 21 CFM damper leakage was reduced to a leakage of 3.8 CFM. In light of the current regulatory climate and the interest in Control Room Habitability issues, imprecise estimates of critical air boundary leakage rates--such as through bubble-tight dampers--are not acceptable. These imprecise estimates can skew radioactive dose assessments as well as chemical contaminant exposure calculations. Using a tracer gas technique, the actual leakage rate can be determined. This knowledge eliminates a significant source of uncertainty in both radioactive dose and/or chemical exposure assessments.

  9. 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.

  10. 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.

  11. 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.

  12. 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).

  13. 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 ...

  14. 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)

  15. 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

  16. 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)

  17. 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.

  18. 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

  19. 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.

  20. 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)

  1. 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.

  2. 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.

  3. 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).

  4. 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).

  5. 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

  6. 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.

  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. 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.

  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. Detection Techniques of Femtosecond Lasers

    Institute of Scientific and Technical Information of China (English)

    LIU Li-peng; ZHOU Ming; DAI Qi-xun; CAI Lan

    2004-01-01

    The measurement techniques of femtosecond spectroscopy are effective method to investigate ultrafast dynamics, they are widely used in the fields of physics, chemistry and biology. In this paper, the principle, experiment setup and the approaches to deal with the experiment data were presented. Then different measurement techniques such as transient absorption spectroscopy, photon echoes, optical Kerr effect and degenerate four-wave mixing were explained with special examples. At last, the application prospect of measurement techniques of femtosecond spectroscopy was forecasted.

  13. Comparing Face Detection and Recognition Techniques

    OpenAIRE

    Korra, Jyothi

    2016-01-01

    This paper implements and compares different techniques for face detection and recognition. One is find where the face is located in the images that is face detection and second is face recognition that is identifying the person. We study three techniques in this paper: Face detection using self organizing map (SOM), Face recognition by projection and nearest neighbor and Face recognition using SVM.

  14. 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.

  15. 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.

  16. 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.

  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. Systemic Capillary Leak Syndrome associated with hypovolemic shock and compartment syndrome. Use of transpulmonary thermodilution technique for volume management

    Directory of Open Access Journals (Sweden)

    Schmid Roland M

    2010-07-01

    Full Text Available Abstract Systemic Capillary Leak Syndrome (SCLS is a rare disorder characterized by increased capillary hyperpermeability leading to hypovolemic shock due to a markedly increased shift of fluid and protein from the intravascular to the interstitial space. Hemoconcentration, hypoalbuminemia and a monoclonal gammopathy are characteristic laboratory findings. Here we present a patient who suffered from SCLS with hypovolemic shock and compartment syndrome of both lower legs and thighs. Volume and catecholamine management was guided using transpulmonary thermodilution. Extended hemodynamic monitoring for volume and catecholamine management as well as monitoring of muscle compartment pressure is of crucial importance in SCLS patients.

  20. Hlaallele Detection Using Molecular Techniques

    Directory of Open Access Journals (Sweden)

    Philip A. Dyer

    1993-01-01

    Full Text Available There are now many molecular biological techniques available to define HLA class I and class II alleles. Some of these are also applicable to other human polymorphic genes, in particular to those non-HLA genes encoded within the Mhc. The range of techniques available allows laboratories to choose those most suited to their purpose. The routine laboratory supporting solid organ transplants will need to type large numbers of potential recipients over a period of time, probably using PCR-SSOP while donors will be typed singly and rapidly using PCR-SSP with HLA allele compatibility determined by heteroduplex analysis. Laboratories supporting bone marrow transplantation, where time is less pressing, can choose from the whole range of techniques to determine accurately donor recipient Mhc compatibility. For disease studies, techniques defining precise HLA allele sequence polymorphisms are needed and high sample numbers have to be accommodated. When an association is established allele sequencing has to be used. In the near future, the precise role of HLA alleles in transplantation and disease susceptibility is likely to be established unambiguously.

  1. Uranium Detection - Technique Validation Report

    Energy Technology Data Exchange (ETDEWEB)

    Colletti, Lisa Michelle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Chemistry Division; Garduno, Katherine [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Chemistry Division; Lujan, Elmer J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Chemistry Division; Mechler-Hickson, Alexandra Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Chemistry Division; Univ. of Wisconsin, Madison, WI (United States); May, Iain [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Chemistry Division; Reilly, Sean Douglas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Chemistry Division

    2016-04-14

    As a LANL activity for DOE/NNSA in support of SHINE Medical Technologies™ ‘Accelerator Technology’ we have been investigating the application of UV-vis spectroscopy for uranium analysis in solution. While the technique has been developed specifically for sulfate solutions, the proposed SHINE target solutions, it can be adapted to a range of different solution matrixes. The FY15 work scope incorporated technical development that would improve accuracy, specificity, linearity & range, precision & ruggedness, and comparative analysis. Significant progress was achieved throughout FY 15 addressing these technical challenges, as is summarized in this report. In addition, comparative analysis of unknown samples using the Davies-Gray titration technique highlighted the importance of controlling temperature during analysis (impacting both technique accuracy and linearity/range). To fully understand the impact of temperature, additional experimentation and data analyses were performed during FY16. The results from this FY15/FY16 work were presented in a detailed presentation, LA-UR-16-21310, and an update of this presentation is included with this short report summarizing the key findings. The technique is based on analysis of the most intense U(VI) absorbance band in the visible region of the uranium spectra in 1 M H2SO4, at λmax = 419.5 nm.

  2. 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.

  3. A review of fade detection techniques

    Science.gov (United States)

    Pergal, F. J.

    1990-01-01

    Several proposed propagation fade detection techniques are reviewed in light of general requirements presented for beacon fade characterization. The discussion includes an analysis of phase lock versus frequency lock beacon tracking loops and of excess noise injection type radiometers. The Advanced Communications Technology Satellite (ACTS) beacon fade detection schemes proposed by the Communications Satellite Corporation and the Jet Propulsion Laboratory are examined along with the fade detection technique used by Harris in the Advanced Communications Technology Satellite (ACTS) low burst rate (LBR) terminal.

  4. 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.

  5. Emboli detection using the Doppler ultrasound technique

    Institute of Scientific and Technical Information of China (English)

    WANG Yuanyuan; CHEN Xi; ZHANG Yu; WANG Weiqi

    2003-01-01

    Embolic detection is very important to the early diagnosis of vessel disease. The Doppler ultrasound technique is one of the common methods to detect the emboli non-invasively. When the emboli pass through the sample volume of the Doppler ultrasound instrument, there exist high intensity transient Doppler signals. Thus the emboli can be detected directly from the variation of Doppler signal amplitude. Since there may be some disturbance in the system, this general detection method has great limitation. To improve the accuracy of emboli auto-detection, several novel methods are studied to obtain the sensitive characteristic of the emboli signals using the new signal processing theories.

  6. 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

  7. Integrated nuclear techniques to detect illicit materials

    Energy Technology Data Exchange (ETDEWEB)

    DeVolpi, A.

    1997-10-01

    This paper discusses the problem of detecting explosives in the context of an object being transported for illicit purposes. The author emphasizes that technologies developed for this particular application have payoffs in many related problem areas. The author discusses nuclear techniques which can be applied to this detection problem. These include: x-ray imaging; neutronic interrogation; inelastic neutron scattering; fieldable neutron generators. He discusses work which has been done on the applications of these technologies, including results for detection of narcotics. He also discusses efforts to integrate these techniques into complementary systems which offer improved performance.

  8. 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.

  9. IMAGE ANALYSIS BASED ON EDGE DETECTION TECHNIQUES

    Institute of Scientific and Technical Information of China (English)

    纳瑟; 刘重庆

    2002-01-01

    A method that incorporates edge detection technique, Markov Random field (MRF), watershed segmentation and merging techniques was presented for performing image segmentation and edge detection tasks. It first applies edge detection technique to obtain a Difference In Strength (DIS) map. An initial segmented result is obtained based on K-means clustering technique and the minimum distance. Then the region process is modeled by MRF to obtain an image that contains different intensity regions. The gradient values are calculated and then the watershed technique is used. DIS calculation is used for each pixel to define all the edges (weak or strong) in the image. The DIS map is obtained. This help as priority knowledge to know the possibility of the region segmentation by the next step (MRF), which gives an image that has all the edges and regions information. In MRF model,gray level l, at pixel location i, in an image X, depends on the gray levels of neighboring pixels. The segmentation results are improved by using watershed algorithm. After all pixels of the segmented regions are processed, a map of primitive region with edges is generated. The edge map is obtained using a merge process based on averaged intensity mean values. A common edge detectors that work on (MRF) segmented image are used and the results are compared. The segmentation and edge detection result is one closed boundary per actual region in the image.

  10. 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.

  11. 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).

  12. RFI Source Detection using Array Beamforming Technique

    OpenAIRE

    2015-01-01

    Accurate localization of microwave emitting sources is an important topic, in telecommunication and remote sensing. Especially, in order to increase the data quality of satellite microwave remote sensing, radio frequency interference (RFI) sources need to be accurately geolocated. This project offers the opportunity to learn and experience the method for high-performance detection and localization of RFI sources. Study of radio frequency interference definition and detection techniques. ...

  13. Detecting hydrosonic signal using a polarization technique

    Institute of Scientific and Technical Information of China (English)

    孟克; 潘玉衡; 安翠珍; 王东红

    2004-01-01

    Some optical fiber hydrophones, such as PGC Mach-Zehnder Interferometer, have a birefringence of single mode optical fibers which induce signal fading. Especially, if two optical beams from the optical arms are orthogonal, the interferomic signal can' t be detected at all. Here a new method is introduced. This is to translate the detected phase difference into a linearly polarized angle, then detect it, so that polarization inducing signal fading will be avoided. In theory, this problem is solved. Furthermore, the effect on measurement results from optical source fluctuation becomes little when using the polarization technique.

  14. 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.

  15. 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.

  16. 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.

  17. Multipath Detection Using Boolean Satisfiability Techniques

    Directory of Open Access Journals (Sweden)

    Fadi A. Aloul

    2011-01-01

    Full Text Available A new technique for multipath detection in wideband mobile radio systems is presented. The proposed scheme is based on an intelligent search algorithm using Boolean Satisfiability (SAT techniques to search through the uncertainty region of the multipath delays. The SAT-based scheme utilizes the known structure of the transmitted wideband signal, for example, pseudo-random (PN code, to effectively search through the entire space by eliminating subspaces that do not contain a possible solution. The paper presents a framework for modeling the multipath detection problem as a SAT application. It also provides simulation results that demonstrate the effectiveness of the proposed scheme in detecting the multipath components in frequency-selective Rayleigh fading channels.

  18. 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.

  19. 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.

  20. Nasogastric tube placement into the hepaticojejunostomy anastomosis in pancreaticoduodenectomy: a simple surgical technique for prevention of bile leak.

    Science.gov (United States)

    Kaya, Bulent; Ozcabi, Yetkin; Tasdelen, Iksan; Onur, Ender; Memisoglu, Kemal

    2016-05-01

    Hepaticojejunostomy is an important part of many surgical procedures including pancreaticoduodenectomy. Biliary leakage from hepaticojejunostomy may be associated with intraabdominal abscess formation, biliary peritonitis, and even mortality. A 72-year-old female patient was admitted to our hospital with obstructive jaundice. After initial evaluation, she was diagnosed with distal common bile duct obstruction without accurate diagnosis. Before planned pancreaticoduodenectomy, biliary drainage with a T-tube was performed due to the presence of cholangitis. After the first operation, pancreaticoduodenectomy was performed. Postinflammatory changes around the hilar region made the hepaticojejunostomy risky. A bilio-digestive anastomosis was performed using a new technique. A nasogastric tube was placed into the common bile duct proximal to the anastomosis. The postoperative course of the patient was uneventful. The use of a nasogastric tube as a stent in risky hepaticojejunostomies is a simple technique that can be beneficial.

  1. 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.

  2. Lung Cancer Detection Using Image Processing Techniques

    Directory of Open Access Journals (Sweden)

    Mokhled S. AL-TARAWNEH

    2012-08-01

    Full Text Available Recently, image processing techniques are widely used in several medical areas for image improvement in earlier detection and treatment stages, where the time factor is very important to discover the abnormality issues in target images, especially in various cancer tumours such as lung cancer, breast cancer, etc. Image quality and accuracy is the core factors of this research, image quality assessment as well as improvement are depending on the enhancement stage where low pre-processing techniques is used based on Gabor filter within Gaussian rules. Following the segmentation principles, an enhanced region of the object of interest that is used as a basic foundation of feature extraction is obtained. Relying on general features, a normality comparison is made. In this research, the main detected features for accurate images comparison are pixels percentage and mask-labelling.

  3. Evaluation of object level change detection techniques

    Science.gov (United States)

    Irvine, John M.; Bergeron, Stuart; Hugo, Doug; O'Brien, Michael A.

    2007-04-01

    A variety of change detection (CD) methods have been developed and employed to support imagery analysis for applications including environmental monitoring, mapping, and support to military operations. Evaluation of these methods is necessary to assess technology maturity, identify areas for improvement, and support transition to operations. This paper presents a methodology for conducting this type of evaluation, discusses the challenges, and illustrates the techniques. The evaluation of object-level change detection methods is more complicated than for automated techniques for processing a single image. We explore algorithm performance assessments, emphasizing the definition of the operating conditions (sensor, target, and environmental factors) and the development of measures of performance. Specific challenges include image registration; occlusion due to foliage, cultural clutter and terrain masking; diurnal differences; and differences in viewing geometry. Careful planning, sound experimental design, and access to suitable imagery with image truth and metadata are critical.

  4. 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

  5. Artificial Intrusion Detection Techniques: A Survey

    Directory of Open Access Journals (Sweden)

    Ashutosh Gupta

    2014-08-01

    Full Text Available Networking has become the most integral part of our cyber society. Everyone wants to connect themselves with each other. With the advancement of network technology, we find this most vulnerable to breach and take information and once information reaches to the wrong hands it can do terrible things. During recent years, number of attacks on networks have been increased which drew the attention of many researchers on this field. There have been many researches on intrusion detection lately. Many methods have been devised which are really very useful but they can only detect the attacks which already took place. These methods will always fail whenever there is a foreign attack which is not famous or which is new to the networking world. In order to detect new intrusions in the network, researchers have devised artificial intelligence technique for Intrusion detection prevention system. In this paper we are going to cover what types evolutionary techniques have been devised and their significance and modification.

  6. 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.

  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. Landmine Detection Technologies to TraceExplosive Vapour Detection Techniques

    Directory of Open Access Journals (Sweden)

    J. C. Kapoor

    2007-11-01

    Full Text Available Large quantity of explosive is manufactured worldwide for use in various types of ammunition,arms, and mines, and used in armed conflicts. During manufacturing and usage of the explosiveequipment, some of the explosive residues are released into the environment in the form ofcontaminated effluents, unburnt explosives fumes and vapours. Limited but uncontrolledcontinuous release of trace vapours also takes place when explosive-laden landmines are deployedin the field. One of the major technological challenges in post-war scenario worldwide is thedetection of landmines using these trace vapour signatures and neutralising them safely.  Differenttypes of explosives are utilised as the main charge in antipersonnel and antitank landmines. Inthis paper, an effort has been made to review the techniques so far available based on explosivevapour detection especially to detect the landmines. A comprehensive compilation of relevantinformation on the techniques is presented, and their maturity levels, shortcomings, and difficultiesfaced are highlighted.

  10. Tumor margin detection using optical biopsy techniques

    Science.gov (United States)

    Zhou, Yan; Liu, Cheng-hui; Li, Jiyou; Li, Zhongwu; Zhou, Lixin; Chen, Ke; Pu, Yang; He, Yong; Zhu, Ke; Li, Qingbo; Alfano, Robert R.

    2014-03-01

    The aim of this study is to use the Resonance Raman (RR) and fluorescence spectroscopic technique for tumor margin detection with high accuracy based on native molecular fingerprints of breast and gastrointestinal (GI) tissues. This tumor margins detection method utilizes advantages of RR spectroscopic technique in situ and in real-time to diagnose tumor changes providing powerful tools for clinical guiding intraoperative margin assessments and postoperative treatments. The tumor margin detection procedures by RR spectroscopy were taken by scanning lesion from center or around tumor region in ex-vivo to find the changes in cancerous tissues with the rim of normal tissues using the native molecular fingerprints. The specimens used to analyze tumor margins include breast and GI carcinoma and normal tissues. The sharp margin of the tumor was found by the changes of RR spectral peaks within 2 mm distance. The result was verified using fluorescence spectra with 300 nm, 320 nm and 340 nm excitation, in a typical specimen of gastric cancerous tissue within a positive margin in comparison with normal gastric tissues. This study demonstrates the potential of RR and fluorescence spectroscopy as new approaches with labeling free to determine the intraoperative margin assessment.

  11. 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.

  12. 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

  13. Image watermark detection techniques using quadtrees

    Directory of Open Access Journals (Sweden)

    Nidaa A. Abbas

    2015-07-01

    Full Text Available The quadtree, a hierarchical data structure for the representation of spatial information based on the principle of recursive decomposition, is widely used in digital image processing and computer graphics. This paper demonstrates the detection of invisible watermarked images generated by popular watermarking techniques, including CDMA, DCT, DWT, and Least Significant Bit (LSB using quadtree. Results corresponding to typical (512 × 512 pixel images show differences among these methods when they are used. Each time we use the same image, the original images and invisible watermarked image to test the four methods in conjunction with quadtree decomposition. In addition to the subjective method represented by quadtree, many objective evaluations such as Pearson correlation, mean square error (MSE, Structural SIMilarity Index (SSIM and false positive and false negative were used to give the comparison criteria between original and watermarked images. In results, the quadtree decomposition considered a promise subjective method to recognize among these watermark techniques.

  14. Detecting Internet Worms Using Data Mining Techniques

    Directory of Open Access Journals (Sweden)

    Muazzam Siddiqui

    2008-12-01

    Full Text Available Internet worms pose a serious threat to computer security. Traditional approaches using signatures to detect worms pose little danger to the zero day attacks. The focus of malware research is shifting from using signature patterns to identifying the malicious behavior displayed by the malwares. This paper presents a novel idea of extracting variable length instruction sequences that can identify worms from clean programs using data mining techniques. The analysis is facilitated by the program control flow information contained in the instruction sequences. Based upon general statistics gathered from these instruction sequences we formulated the problem as a binary classification problem and built tree based classifiers including decision tree, bagging and random forest. Our approach showed 95.6% detection rate on novel worms whose data was not used in the model building process.

  15. A New Generic Taxonomy on Hybrid Malware Detection Technique

    CERN Document Server

    Robiah, Y; Zaki, M Mohd; Shahrin, S; Faizal, M A; Marliza, R

    2009-01-01

    Malware is a type of malicious program that replicate from host machine and propagate through network. It has been considered as one type of computer attack and intrusion that can do a variety of malicious activity on a computer. This paper addresses the current trend of malware detection techniques and identifies the significant criteria in each technique to improve malware detection in Intrusion Detection System (IDS). Several existing techniques are analyzing from 48 various researches and the capability criteria of malware detection technique have been reviewed. From the analysis, a new generic taxonomy of malware detection technique have been proposed named Hybrid Malware Detection Technique (Hybrid MDT) which consists of Hybrid Signature and Anomaly detection technique and Hybrid Specification based and Anomaly detection technique to complement the weaknesses of the existing malware detection technique in detecting known and unknown attack as well as reducing false alert before and during the intrusion ...

  16. Detection of biological aerosols by luminescence techniques

    Science.gov (United States)

    Stopa, Peter J.; Tieman, Darlene; Coon, Phillip A.; Paterno, Dorothea A.; Milton, Maurice M.

    1999-12-01

    Luciferin-Luciferase (L-L) luminescence techniques were used to successfully measure adenosine triphosphate (ATP) (pg/ml) in concentrated aerosol samples containing either vegetative bacterial cells or spores. Aerosols were collected with wet and dry sampling devices. Evaluation for the presence of total bio-mass from bacterial and non-bacterial sources of ATP was achieved by suspending the collected aerosol samples in phosphate buffered saline (PBS), pipeting a 50-(mu) l aliquot of the PBS suspension into a FiltravetteTM, and then adding bacterial releasing agent (BRA). The sample was then reacted with L-L, and the resulting Relative Luminescence Units (RLU's), indicative of ATP from all sources, were measured. Bacterial cells were enumerated with the additional application of a wash with somatic cell releasing agent (SRA) to remove any interferences and non-bacterial sources of ATP prior to BRA application. This step removes interfering substances and non-bacterial sources of ATP. For spore analysis, an equi-volume sample of the PBS suspension was added to an equi-volume of trypticase soy broth (TSB), incubated at 37 C for 15 minutes, and processed using methods identical to bacterial cell analysis. Using these technique we were able to detect Bacillus subtilin variation niger, formerly known as Bacillus globigii (BG), in aerosol samples at concentrations greater than or equal to 105 colony forming units (CFU) per ml. Results of field and chamber trials show that one can detect the presence of bacterial and non-bacterial sources of ATP. One can also differentiate spore and vegetative bacterial cells. These techniques may be appropriate to situations where the measurement of bacterial aerosols is needed.

  17. 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.

  18. 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

  19. 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...

  20. Chipless RFID design procedure and detection techniques

    CERN Document Server

    Rezaiesarlak, Reza

    2015-01-01

    This book examines the design of chipless RFID systems. The authors begin with the historical development of wireless identification systems and finally arrive at a representation of the chipless RFID system as a block diagram illustration. Chapter 2 is devoted to the theoretical bases for the design of chipless RFID tags and detection techniques in the reader. A rigorous mathematical formulation is presented based on the singularity expansion method (SEM) and characteristic mode theory (CMT) in order to study the scattered fields from an object in a general form. Th e authors attempt to explain some physical concepts behind the mathematical descriptions of the theories in this chapter. In Chapter 3, two design procedures based on complex natural resonance and CMT are presented for the design of the chipless RFID tag. By studying the effects of structural parameters on radiation and resonant behaviors of the tag, some design conclusions are presented in this chapter. Chapter 4 is dedicated to the time-frequen...

  1. 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.

  2. 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.

  3. 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)

  4. 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.

  5. 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.

  6. 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.

  7. Novel absorption detection techniques for capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Yongjun [Iowa State Univ., Ames, IA (United States)

    1994-07-27

    Capillary electrophoresis (CE) has emerged as one of the most versatile separation methods. However, efficient separation is not sufficient unless coupled to adequate detection. The narrow inner diameter (I.D.) of the capillary column raises a big challenge to detection methods. For UV-vis absorption detection, the concentration sensitivity is only at the μM level. Most commercial CE instruments are equipped with incoherent UV-vis lamps. Low-brightness, instability and inefficient coupling of the light source with the capillary limit the further improvement of UV-vis absorption detection in CE. The goals of this research have been to show the utility of laser-based absorption detection. The approaches involve: on-column double-beam laser absorption detection and its application to the detection of small ions and proteins, and absorption detection with the bubble-shaped flow cell.

  8. Autonomous obstacle detection and avoidance techniques for lunar lander

    Science.gov (United States)

    Li, Shuang; Peng, Yuming

    Autonomous obstacle detection and avoidance (AODA) techniques is prerequisite for future pinpoint lunar landing missions. Information weighted fusion hazard detection algorithms are firstly proposed to improve the success probability of obstacle detection. Secondly, guidance law for constant-thrust engine is designed to avoid the detected obstacles and steer the lander to the safe landing site. Finally, the validity of the proposed obstacle detection and avoidance techniques are confirmed by computer simulation.

  9. Breath analysis using laser spectroscopic techniques: breath biomarkers, spectral fingerprints, and detection limits.

    Science.gov (United States)

    Wang, Chuji; Sahay, Peeyush

    2009-01-01

    Breath analysis, a promising new field of medicine and medical instrumentation, potentially offers noninvasive, real-time, and point-of-care (POC) disease diagnostics and metabolic status monitoring. Numerous breath biomarkers have been detected and quantified so far by using the GC-MS technique. Recent advances in laser spectroscopic techniques and laser sources have driven breath analysis to new heights, moving from laboratory research to commercial reality. Laser spectroscopic detection techniques not only have high-sensitivity and high-selectivity, as equivalently offered by the MS-based techniques, but also have the advantageous features of near real-time response, low instrument costs, and POC function. Of the approximately 35 established breath biomarkers, such as acetone, ammonia, carbon dioxide, ethane, methane, and nitric oxide, 14 species in exhaled human breath have been analyzed by high-sensitivity laser spectroscopic techniques, namely, tunable diode laser absorption spectroscopy (TDLAS), cavity ringdown spectroscopy (CRDS), integrated cavity output spectroscopy (ICOS), cavity enhanced absorption spectroscopy (CEAS), cavity leak-out spectroscopy (CALOS), photoacoustic spectroscopy (PAS), quartz-enhanced photoacoustic spectroscopy (QEPAS), and optical frequency comb cavity-enhanced absorption spectroscopy (OFC-CEAS). Spectral fingerprints of the measured biomarkers span from the UV to the mid-IR spectral regions and the detection limits achieved by the laser techniques range from parts per million to parts per billion levels. Sensors using the laser spectroscopic techniques for a few breath biomarkers, e.g., carbon dioxide, nitric oxide, etc. are commercially available. This review presents an update on the latest developments in laser-based breath analysis.

  10. Breath Analysis Using Laser Spectroscopic Techniques: Breath Biomarkers, Spectral Fingerprints, and Detection Limits

    Directory of Open Access Journals (Sweden)

    Peeyush Sahay

    2009-10-01

    Full Text Available Breath analysis, a promising new field of medicine and medical instrumentation, potentially offers noninvasive, real-time, and point-of-care (POC disease diagnostics and metabolic status monitoring. Numerous breath biomarkers have been detected and quantified so far by using the GC-MS technique. Recent advances in laser spectroscopic techniques and laser sources have driven breath analysis to new heights, moving from laboratory research to commercial reality. Laser spectroscopic detection techniques not only have high-sensitivity and high-selectivity, as equivalently offered by the MS-based techniques, but also have the advantageous features of near real-time response, low instrument costs, and POC function. Of the approximately 35 established breath biomarkers, such as acetone, ammonia, carbon dioxide, ethane, methane, and nitric oxide, 14 species in exhaled human breath have been analyzed by high-sensitivity laser spectroscopic techniques, namely, tunable diode laser absorption spectroscopy (TDLAS, cavity ringdown spectroscopy (CRDS, integrated cavity output spectroscopy (ICOS, cavity enhanced absorption spectroscopy (CEAS, cavity leak-out spectroscopy (CALOS, photoacoustic spectroscopy (PAS, quartz-enhanced photoacoustic spectroscopy (QEPAS, and optical frequency comb cavity-enhanced absorption spectroscopy (OFC-CEAS. Spectral fingerprints of the measured biomarkers span from the UV to the mid-IR spectral regions and the detection limits achieved by the laser techniques range from parts per million to parts per billion levels. Sensors using the laser spectroscopic techniques for a few breath biomarkers, e.g., carbon dioxide, nitric oxide, etc. are commercially available. This review presents an update on the latest developments in laser-based breath analysis.

  11. COMPARATIVE STUDY OF DIFFERENTEDGE DETECTION TECHNIQUES

    OpenAIRE

    Beant Kaur,; Anil Garg

    2011-01-01

    Detection of edge is a terminology in image processing and computer vision particularly in the areas of feature detection and extraction to refer to the algorithms which aims at identifying points in a digital image at which the image brightness changes sharply or more formally has discontinuities. The need of edge detection is to find the discontinuities in depth, discontinuities in surface orientation, changes in material properties and variations in scene illumination. Remote sensing image...

  12. Sensitive Infrared Signal Detection by Upconversion Technique

    Science.gov (United States)

    Wong, Teh-Hwa; Yu, Jirong; Bai, Yingxin; Johnson, William; Chen, Songsheng; Petros, Mulugeta; Singh, Upendra N.

    2014-01-01

    We demonstrated upconversion assisted detection of a 2.05-micron signal by sum frequency generation to generate a 700-nm light using a bulk periodically poled lithium niobate crystal. The achieved 94% intrinsic upconversion efficiency and 22.58% overall detection efficiency at a pW level of 2.05 micron pave the path to detect extremely weak infrared (IR) signals for remote sensing applications.

  13. Scalable lidar technique for fire detection

    Science.gov (United States)

    Utkin, Andrei B.; Piedade, Fernando; Beixiga, Vasco; Mota, Pedro; Lousã, Pedro

    2014-08-01

    Lidar (light detection and ranging) presents better sensitivity than fire surveillance based on imaging. However, the price of conventional lidar equipment is often too high as compared to passive fire detection instruments. We describe possibilities to downscale the technology. First, a conventional lidar, capable of smoke-plume detection up to ~10 km, may be replaced by an industrially manufactured solid-state laser rangefinder. This reduces the detection range to about 5 km, but decreases the purchase price by one order of magnitude. Further downscaling is possible by constructing the lidar smoke sensor on the basis of a low-cost laser diode.

  14. 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。

  15. 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)

  16. Infrared Signal Detection by Upconversion Technique

    Science.gov (United States)

    Wong, Teh-Hwa; Yu, Jirong; Bai, Yingxin; Johnson, William E.

    2014-01-01

    We demonstrated up-conversion assisted detection of a 2.05-micron signal by using a bulk periodically poled Lithium niobate crystal. The 94% intrinsic up-conversion efficiency and 22.58% overall detection efficiency at pW level of 2.05-micron was achieved.

  17. Study of Associated α Particle Imaging Technique for Explosives Detection

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The explosive detecting technique about neutron mainly include the thermal neutron analysis (TNA), the fast neutron analysis (FNA), the pulse fast and thermal neutron analysis (PFTNA) and the associated α particle imaging technique about fast neutron (API).

  18. 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

  19. 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.

  20. 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.

  1. NQR Stimulation Technique for Explosives Detection System

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A method of customization stimulation signal based on direct digital frequency synthesis (DDS) for Nuclear Quadrapole Resonance Explosives Detection System is presented. DDS has many advantages, such as high frequency resolution, high convert speed,

  2. Investigation of New Techniques for Face detection

    OpenAIRE

    Abdallah, Abdallah Sabry

    2007-01-01

    The task of detecting human faces within either a still image or a video frame is one of the most popular object detection problems. For the last twenty years researchers have shown great interest in this problem because it is an essential pre-processing stage for computing systems that process human faces as input data. Example applications include face recognition systems, vision systems for autonomous robots, human computer interaction systems (HCI), surveillance systems, biometric based a...

  3. 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.

  4. Heat detection techniques in cattle and buffalo

    Directory of Open Access Journals (Sweden)

    Thakur Krishna Shankar Rao

    2013-12-01

    Full Text Available Proper heat detection to achieve appropriate timing of insemination is the biggest restriction in attaining high conception rate in dairy herd. The estrus detection is the key issue to be considered on priority basis. Inefficient heat detection reduces the fertility status of herd. Interventions in existing management practices in farm can manifest estrus with clarity. Manifestation of estrus is due to effect of estrogen on Central Nervous System (CNS. The standing to be ridden is the best reliable sign of estrus. Ovulation time is well estimated by standing heat. Different factors are responsible which affect estrous behavior, out of which feeding and management interventions are one of the most important factors. For improving efficiency of heat detection in animal visual observation is best method, if it is done thrice a day for 30 minutes every time. However heat detection aids, if used in combination give better results as compared to visual observation. The progesterone (P4 estimation in milk and ultrasound monitoring of ovary and reproductive tracts for estimation of ovulation time are other important methods. Ovulation is very important point in dairy reproduction management. The optimum time for insemination is before the actual ovulation. It is already established that, estrus detection alone contributes considerably to reproductive status of the herd, therefore the need of the hour is critical observation of dairy herd to reduce incidence of unnoticed estrus. [Vet World 2013; 6(6.000: 363-369

  5. Battlefield triage life signs detection techniques

    Science.gov (United States)

    Boric-Lubecke, Olga; Lin, Jenshan; Park, Byung-Kwon; Li, Changzhi; Massagram, Wansuree; Lubecke, Victor M.; Host-Madsen, Anders

    2008-04-01

    Getting to wounded soldiers on the battlefield is a precarious task, and medics have a very high casualty rate. It is therefore a vital importance to prioritize which soldiers to attend to first. The first step is to detect life signs - if a soldier is dead or alive, and prioritize recovery of live soldiers. The second step is to obtain vital signs from live soldiers, and use this to prioritize which are in most urgent need of attention. Our team at Kai Sensors, University of Hawaii and University of Florida is developing Doppler radar heart sensing technology that provides the means to detect life signs, respiration and/or heart beat, at a distance, even for subjects lying motionless, e.g., unconscious subjects, wearing body armor, and hidden from direct view. Since this technology can deliver heart rate information with high accuracy, it may also enable the assessment of a subject's physiological and psychological state based on heart rate variability (HRV) analysis. Thus, the degree of a subject's injury may also be determined. The software and hardware developments and challenges for life signs detection and monitoring for battlefield triage will be discussed, including heart signal detection from all four sides of the human body, detection in the presence of body armor, and the feasibility of HRV parameter extraction.

  6. Feature detection techniques for preprocessing proteomic data.

    Science.gov (United States)

    Sellers, Kimberly F; Miecznikowski, Jeffrey C

    2010-01-01

    Numerous gel-based and nongel-based technologies are used to detect protein changes potentially associated with disease. The raw data, however, are abundant with technical and structural complexities, making statistical analysis a difficult task. Low-level analysis issues (including normalization, background correction, gel and/or spectral alignment, feature detection, and image registration) are substantial problems that need to be addressed, because any large-level data analyses are contingent on appropriate and statistically sound low-level procedures. Feature detection approaches are particularly interesting due to the increased computational speed associated with subsequent calculations. Such summary data corresponding to image features provide a significant reduction in overall data size and structure while retaining key information. In this paper, we focus on recent advances in feature detection as a tool for preprocessing proteomic data. This work highlights existing and newly developed feature detection algorithms for proteomic datasets, particularly relating to time-of-flight mass spectrometry, and two-dimensional gel electrophoresis. Note, however, that the associated data structures (i.e., spectral data, and images containing spots) used as input for these methods are obtained via all gel-based and nongel-based methods discussed in this manuscript, and thus the discussed methods are likewise applicable.

  7. Screening techniques for detecting chronic kidney disease

    NARCIS (Netherlands)

    de Jong, PE; Gansevoort, RT

    2005-01-01

    Purpose of review As patients with impaired kidney function are at increased risk not only for progressive renal function loss, but also for cardiovascular disease, it is of importance to have accurate techniques to screen patients for the presence of an impaired kidney function. Recent findings Glo

  8. Intracoronary Thermography: a vulnerable Plaque Detection Technique?

    NARCIS (Netherlands)

    A.G. ten Have (Anna)

    2006-01-01

    textabstractThe studies reported in this thesis were performed to answer the central question: can intracoronary thermography be used for vulnerable plaque detection? To answer this question, we have identified parameters that influence intracoronary thermography measurements, and have studied to w

  9. Laser Photoacoustic Technique Detects Photo-Oxidation

    Science.gov (United States)

    Liange, R. H.; Coulter, D. R.; Gupta, A.

    1986-01-01

    Laser photoacoustic instrument detects small amounts of oxidation in polymers. Instrument used to evaluate resistance to oxidation in Sunlight of polymer encapsulants for solar-cell arrays. With instrument, researchers monitor samples for early stages of photooxidation and study primary mechanisms of oxidation and degradation. Effects of these mechanisms masked during later stages.

  10. On Bitstream Based Edge Detection Techniques

    Science.gov (United States)

    2009-01-01

    Rafael C. Gonzalez and Richard E. Woods, Digital Image Processing , Addison-Wesley...Longman Publishing Co., Inc., Boston, MA, USA, 2001. [6] William K Pratt, Digital image processing , Wiley, New York :, 1991. [7] Miguel Segui Prieto and...bitstream processing 1. INTRODUCTION Edge detection is a vital part of image processing , which is used for extracting important features from an image

  11. 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.

  12. 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.

  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. Detection of Gaseous Compounds with Different Techniques

    Directory of Open Access Journals (Sweden)

    Mikołajczyk Janusz

    2016-06-01

    Full Text Available Sensing technology has been developed for detection of gases in some environmental, industrial, medical, and scientific applications. The main tasks of these works is to enhance performance of gas sensors taking into account their different applicability and scenarios of operation. This paper presents the descriptions, comparison and recent progress in some existing gas sensing technologies. Detailed introduction to optical sensing methods is presented. In a general way, other kinds of various sensors, such as catalytic, thermal conductivity, electrochemical, semiconductor and surface acoustic wave ones, are also presented. Furthermore, this paper focuses on performance of the optical method in detecting biomarkers in the exhaled air. There are discussed some examination results of the constructed devices. The devices operated on the basis of enhanced cavity and wavelength modulation spectroscopies. The experimental data used for analyzing applicability of these different sensing technologies in medical screening. Several suggestions related to future development are also discussed.

  16. Detection and Estimation Techniques in Cognitive Radio

    OpenAIRE

    Shen, Juei-Chin

    2013-01-01

    Faced with imminent spectrum scarcity largely due to inflexible licensed band arrangements, cognitive radio (CR) has been proposed to facilitate higher spectrum utilization by allowing cognitive users (CUs) to access the licensed bands without causing harmful interference to primary users (PUs). To achieve this without the aid of PUs, the CUs have to perform spectrum sensing reliably detecting the presence or absence of PU signals. Without reliable spectrum sensing, the discovery of spectrum ...

  17. Review of Transportation Mode Detection techniques

    Directory of Open Access Journals (Sweden)

    Jacopo Biancat

    2014-10-01

    Full Text Available This paper reviews the works found in the literature in the field of Transportation Mode Detection (TMD which is a subfield of Activity Recognition aiming at indentifying (i.e. classifying the mean of transportation a person is using. The solutions found in literature have different characteristics according to the device for which the solution was tailored (smartphones or other systems such as, e.g., GPS loggers and to the algorithm used for the classification task. This may vary a lot according to the number and type of input used (e.g. accelerations, GPS, maps information or GIS - Geographical Information System information and to the identified classes of transportation mode. These two aspects are the most relevant to consider when evaluating and comparing the accuracies claimed by each work. A comparison of the works is proposed taking into account the characteristics discussed above. In general the accelerometer is the most widely used sensor for TMD applications, as it limits battery consumption and captures relevant features for detecting motion. Indeed a key challenge in TMD is to detect different motorized classes such as bus, car, train and metro because they share common characteristics (such as e.g. the average speed and accelerations which make hard identifying suitable features for the classification algorithm. Identifying the “walk” and “stationary” transportation modes is a simpler task because they are characterized by distinct features.

  18. Comparison of Machine Learning Techniques for Target Detection

    NARCIS (Netherlands)

    Vink, J.P.; Haan, G. de

    2013-01-01

    This paper focuses on machine learning techniques for real-time detection. Although many supervised learning techniques have been described in the literature, no technique always performs best. Several comparative studies are available, but have not always been performedcarefully, leading to invalid

  19. Comparison of Machine Learning Techniques for Target Detection

    NARCIS (Netherlands)

    Vink, J.P.; Haan, G. de

    2013-01-01

    This paper focuses on machine learning techniques for real-time detection. Although many supervised learning techniques have been described in the literature, no technique always performs best. Several comparative studies are available, but have not always been performedcarefully, leading to invalid

  20. Advanced Statistical Signal Processing Techniques for Landmine Detection Using GPR

    Science.gov (United States)

    2014-07-12

    Processing Techniques for Landmine Detection Using GPR The views, opinions and/or findings contained in this report are those of the author(s) and should not...AGENCY NAME(S) AND ADDRESS (ES) U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 landmine Detection, Signal...310 Jesse Hall Columbia, MO 65211 -1230 654808 633606 ABSTRACT Advanced Statistical Signal Processing Techniques for Landmine Detection Using GPR Report

  1. 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。

  2. 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).

  3. Nonlinear acoustic techniques for landmine detection.

    Science.gov (United States)

    Korman, Murray S; Sabatier, James M

    2004-12-01

    Measurements of the top surface vibration of a buried (inert) VS 2.2 anti-tank plastic landmine reveal significant resonances in the frequency range between 80 and 650 Hz. Resonances from measurements of the normal component of the acoustically induced soil surface particle velocity (due to sufficient acoustic-to-seismic coupling) have been used in detection schemes. Since the interface between the top plate and the soil responds nonlinearly to pressure fluctuations, characteristics of landmines, the soil, and the interface are rich in nonlinear physics and allow for a method of buried landmine detection not previously exploited. Tuning curve experiments (revealing "softening" and a back-bone curve linear in particle velocity amplitude versus frequency) help characterize the nonlinear resonant behavior of the soil-landmine oscillator. The results appear to exhibit the characteristics of nonlinear mesoscopic elastic behavior, which is explored. When two primary waves f1 and f2 drive the soil over the mine near resonance, a rich spectrum of nonlinearly generated tones is measured with a geophone on the surface over the buried landmine in agreement with Donskoy [SPIE Proc. 3392, 221-217 (1998); 3710, 239-246 (1999)]. In profiling, particular nonlinear tonals can improve the contrast ratio compared to using either primary tone in the spectrum.

  4. Airborne myxomycete spores: detection using molecular techniques

    Science.gov (United States)

    Kamono, Akiko; Kojima, Hisaya; Matsumoto, Jun; Kawamura, Kimitaka; Fukui, Manabu

    2009-01-01

    Myxomycetes are organisms characterized by a life cycle that includes a fruiting body stage. Myxomycete fruiting bodies contain spores, and wind dispersal of the spores is considered important for this organism to colonize new areas. In this study, the presence of airborne myxomycetes and the temporal changes in the myxomycete composition of atmospheric particles (aerosols) were investigated with a polymerase chain reaction (PCR)-based method for Didymiaceae and Physaraceae. Twenty-one aerosol samples were collected on the roof of a three-story building located in Sapporo, Hokkaido Island, northern Japan. PCR analysis of DNA extracts from the aerosol samples indicated the presence of airborne myxomycetes in all the samples, except for the one collected during the snowfall season. Denaturing gradient gel electrophoresis (DGGE) analysis of the PCR products showed seasonally varying banding patterns. The detected DGGE bands were subjected to sequence analyses, and four out of nine obtained sequences were identical to those of fruiting body samples collected in Hokkaido Island. It appears that the difference in the fruiting period of each species was correlated with the seasonal changes in the myxomycete composition of the aerosols. Molecular evidence shows that newly formed spores are released and dispersed in the air, suggesting that wind-driven dispersal of spores is an important process in the life history of myxomycetes. This study is the first to detect airborne myxomycetes with the use of molecular ecological analyses and to characterize their seasonal distribution.

  5. Interferometer Techniques for Gravitational-Wave Detection

    Directory of Open Access Journals (Sweden)

    Andreas Freise

    2010-02-01

    Full Text Available Several km-scale gravitational-wave detectors have been constructed world wide. These instruments combine a number of advanced technologies to push the limits of precision length measurement. The core devices are laser interferometers of a new kind; developed from the classical Michelson topology these interferometers integrate additional optical elements, which significantly change the properties of the optical system. Much of the design and analysis of these laser interferometers can be performed using well-known classical optical techniques, however, the complex optical layouts provide a new challenge. In this review we give a textbook-style introduction to the optical science required for the understanding of modern gravitational wave detectors, as well as other high-precision laser interferometers. In addition, we provide a number of examples for a freely available interferometer simulation software and encourage the reader to use these examples to gain hands-on experience with the discussed optical methods.

  6. Interferometer techniques for gravitational-wave detection

    Science.gov (United States)

    Bond, Charlotte; Brown, Daniel; Freise, Andreas; Strain, Kenneth A.

    2016-12-01

    Several km-scale gravitational-wave detectors have been constructed worldwide. These instruments combine a number of advanced technologies to push the limits of precision length measurement. The core devices are laser interferometers of a new kind; developed from the classical Michelson topology these interferometers integrate additional optical elements, which significantly change the properties of the optical system. Much of the design and analysis of these laser interferometers can be performed using well-known classical optical techniques; however, the complex optical layouts provide a new challenge. In this review, we give a textbook-style introduction to the optical science required for the understanding of modern gravitational wave detectors, as well as other high-precision laser interferometers. In addition, we provide a number of examples for a freely available interferometer simulation software and encourage the reader to use these examples to gain hands-on experience with the discussed optical methods.

  7. Survey on Techniques for Detecting Data Leakage

    Directory of Open Access Journals (Sweden)

    Bhosale Pranjali A

    2016-06-01

    Full Text Available In current business scenario, critical data is to be shared and transferred by organizations to many stake holders in order to complete particular task. The critical data include intellectual copyright, patient information etc. The activities like sharing and transferring of such critical data includes threats like leakage of information, misuse of data, illegal access to data and/or alteration of data. It is necessary to deal with such problem efficiently and effectively, popular solutions to this problem are use of firewalls, data loss prevention tools and watermarking. But sometimes culprit succeeds in overcoming such security measures hence, if organizations becomes able to find out the guilty client responsible for leakage of particular data then risk of data leakage is reduced. For this many systems are proposed, this paper includes information about techniques discussed in some of such methodologies.

  8. 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

  9. 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.

  10. 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)

  11. Hyperspectral Technique for Detecting Soil Parameters

    Science.gov (United States)

    Garfagnoli, F.; Ciampalini, A.; Moretti, S.; Chiarantini, L.

    2011-12-01

    In satellite and airborne remote sensing, hyperspectral technique has become a very powerful tool, due to the possibility of rapidly realizing chemical/mineralogical maps of the studied areas. Many studies are trying to customize the algorithms to identify several geo-physical soil properties. The specific objective of this study is to investigate those soil characteristics, such as clay mineral content, influencing degradation processes (soil erosion and shallow landslides), by means of correlation analysis, in order to examine the possibility of predicting the selected property using high-resolution reflectance spectra and images. The study area is located in the Mugello basin, about 30 km north of Firenze (Tuscany, Italy). Agriculturally suitable terrains are assigned mainly to annual crops, marginally to olive groves, vineyards and orchards. Soils mostly belong to Regosols and Cambisols orders. An ASD FieldSpec spectroradiometer was used to obtain reflectance spectra from about 80 dried, crushed and sieved samples under controlled laboratory conditions. Samples were collected simultaneously with the flight of SIM.GA hyperspectral camera from Selex Galileo, over an area of about 5 km2 and their positions were recorded with a differential GPS. The quantitative determination of clay minerals content was performed by means of XRD and Rietveld refinement. Different chemometric techniques were preliminarily tested to correlate mineralogical records with reflectance data. A one component partial least squares regression model yielded a preliminary R2 value of 0.65. A slightly better result was achieved by plotting the absorption peak depth at 2210 versus total clay content (band-depth analysis). The complete SIM.GA hyperspectral geocoded row dataset, with an approximate pixel resolution of 0.6 m (VNIR) and 1.2 m (SWIR), was firstly transformed into at sensor radiance values, by applying calibration coefficients and parameters from laboratory measurements to non

  12. Protection without detection: a threat mitigation technique

    Science.gov (United States)

    White, Joshua; McCoy, Joseph R.; Ratazzi, Paul

    2012-05-01

    Networking systems and individual applications have traditionally been defended using signature-based tools that protect the perimeter, many times to the detriment of service, performance, and information flow. These tools require knowledge of both the system on which they run and the attack they are preventing. As such, by their very definition, they only account for what is known to be malicious and ignore the unknown. The unknown, or zero day threat, can occur when defenses have yet to be immunized via a signature or other identifier of the threat. In environments where execution of the mission is paramount, the networks and applications must perform their function of information delivery without endangering the enterprise or losing the salient information, even when facing zero day threats. In this paper we, describe a new defensive strategy that provides a means to more deliberately balance the oft mutually exclusive aspects of protection and availability. We call this new strategy Protection without Detection, since it focuses on network protection without sacrificing information availability. The current instantiation analyzes the data stream in real time as it passes through an in-line device. Critical files are recognized, and mission-specific trusted templates are applied as they are forwarded to their destination. The end result is a system which eliminates the opportunity for propagation of malicious or unnecessary payloads via the various containers that are inherent in the definition of standard file types. In some cases, this method sacrifices features or functionality that is typically inherent in these files. However, with the flexibility of the template approach, inclusion or exclusion of these features becomes a deliberate choice of the mission owners, based on their needs and amount of acceptable risk. The paper concludes with a discussion of future extensions and applications.

  13. 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

  14. Biliary leaks after laparoscopic cholecystectomy:timetostentortimetodrain

    Institute of Scientific and Technical Information of China (English)

    Haim Pinkas; Patrick G. Brady

    2008-01-01

    to the nature of this intermittent endoscopic approach but an accurate comparison of time to leak closure could not be determined. Leak closure resulted once the bile lfow was re-established, regardless of the technique, but removal of the NB drains was performed earlier than removal of the biliary stents. The number of ERCPs required per patient was 1.0±0 in the NB group and 2.2±0.1 (range 2-3) in the internal stent group. The length of hospitalization was 8.7±3.3 days for the NB group and 7.5±2.3 days for the internal stent group. Biliary stent placement resulted in an insigniifcant decrease in hospitalization at the expense of generating twice as many endoscopic procedures. CONCLUSIONS: Our data suggest that NB drainage may be advantageous in patients requiring a prolonged hospital admission or in patients in whom repeat endoscopy is undesirable. Internal biliary stenting appears preferable when early discharge is anticipated or when expertise in placement and management of NB drains is lacking.

  15. Analyzing edge detection techniques for feature extraction in dental radiographs

    Directory of Open Access Journals (Sweden)

    Kanika Lakhani

    2016-09-01

    Full Text Available Several dental problems can be detected using radiographs but the main issue with radiographs is that they are not very prominent. In this paper, two well known edge detection techniques have been implemented for a set of 20 radiographs and number of pixels in each image has been calculated. Further, Gaussian filter has been applied over the images to smoothen the images so as to highlight the defect in the tooth. If the images data are available in the form of pixels for both healthy and decayed tooth, the images can easily be compared using edge detection techniques and the diagnosis is much easier. Further, Laplacian edge detection technique is applied to sharpen the edges of the given image. The aim is to detect discontinuities in dental radiographs when compared to original healthy tooth. Future work includes the feature extraction on the images for the classification of dental problems.

  16. 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

  17. Implementation of Advanced Techniques for Automated Freeway Incident Detection

    OpenAIRE

    Abdulhai, Baher; Ritchie, Stephen G.; Iyer, Mahadevan

    1999-01-01

    A significant body of research on advanced techniques for automated freeway incident detection has been conducted at the University of California, Irvine (UCI). Such advanced pattern recognition techniques as artificial neural networks (ANNs) have been thoroughly investigated and their potential superiority to other techniques has been demonstrated. Of the investigated ANN architectures, two have shown the best potential for real-time implementation: namely, the Probabilistic Neural Network (...

  18. Imaging technique for detection of internal defects of pickling cucumbers

    Science.gov (United States)

    Pickling cucumbers are susceptible to damage during harvest and postharvest handling and processing. While it is easier to detect external defects, it is difficult to detect internal defects such as bruises and hollow or split cucumbers. Hyperspectral imaging technique under transmittance mode was i...

  19. Eye State and Head Position Technique for Driver Drowsiness Detection

    Directory of Open Access Journals (Sweden)

    Ayush Joshi

    2013-06-01

    Full Text Available Many Driver Drowsiness Detection systems have been developed using eye and face detection methods but in this paper we have advanced the previous systems by adding the concept of head position technique. Till now none of the systems developed, have used the head position of the driver to detect the drowsiness, every paper have focused only on the face and eye detection concept. The head position technique is a newly introduced feature which enhances the performance of the system to a great extent. The systems capture frame and detects the face and eyes using HAAR-like classifiers, if the face is detected and eyes are closed then head position is monitored for next few frames, if the face is aligning down gradually and continuously then the alarm is activated.

  20. 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.

  1. Planetary Gearbox Fault Detection Using Vibration Separation Techniques

    Science.gov (United States)

    Lewicki, David G.; LaBerge, Kelsen E.; Ehinger, Ryan T.; Fetty, Jason

    2011-01-01

    Studies were performed to demonstrate the capability to detect planetary gear and bearing faults in helicopter main-rotor transmissions. The work supported the Operations Support and Sustainment (OSST) program with the U.S. Army Aviation Applied Technology Directorate (AATD) and Bell Helicopter Textron. Vibration data from the OH-58C planetary system were collected on a healthy transmission as well as with various seeded-fault components. Planetary fault detection algorithms were used with the collected data to evaluate fault detection effectiveness. Planet gear tooth cracks and spalls were detectable using the vibration separation techniques. Sun gear tooth cracks were not discernibly detectable from the vibration separation process. Sun gear tooth spall defects were detectable. Ring gear tooth cracks were only clearly detectable by accelerometers located near the crack location or directly across from the crack. Enveloping provided an effective method for planet bearing inner- and outer-race spalling fault detection.

  2. 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.

  3. 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.

  4. 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.

  5. Analytical detection techniques for droplet microfluidics—A review

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ying [Institute of Microanalytical Systems, Department of Chemistry, Zhejiang University, Hangzhou, 310058 (China); State Key Laboratory of Industrial Control Technology, Institute of Cyber-Systems and Control, Zhejiang University, Hangzhou, 310058 (China); Fang, Qun, E-mail: fangqun@zju.edu.cn [Institute of Microanalytical Systems, Department of Chemistry, Zhejiang University, Hangzhou, 310058 (China)

    2013-07-17

    Graphical abstract: -- Highlights: •This is the first review paper focused on the analytical techniques for droplet-based microfluidics. •We summarized the analytical methods used in droplet-based microfluidic systems. •We discussed the advantage and disadvantage of each method through its application. •We also discuss the future development direction of analytical methods for droplet-based microfluidic systems. -- Abstract: In the last decade, droplet-based microfluidics has undergone rapid progress in the fields of single-cell analysis, digital PCR, protein crystallization and high throughput screening. It has been proved to be a promising platform for performing chemical and biological experiments with ultra-small volumes (picoliter to nanoliter) and ultra-high throughput. The ability to analyze the content in droplet qualitatively and quantitatively is playing an increasing role in the development and application of droplet-based microfluidic systems. In this review, we summarized the analytical detection techniques used in droplet systems and discussed the advantage and disadvantage of each technique through its application. The analytical techniques mentioned in this paper include bright-field microscopy, fluorescence microscopy, laser induced fluorescence, Raman spectroscopy, electrochemistry, capillary electrophoresis, mass spectrometry, nuclear magnetic resonance spectroscopy, absorption detection, chemiluminescence, and sample pretreatment techniques. The importance of analytical detection techniques in enabling new applications is highlighted. We also discuss the future development direction of analytical detection techniques for droplet-based microfluidic systems.

  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. The detection of bulk explosives using nuclear-based techniques

    Energy Technology Data Exchange (ETDEWEB)

    Morgado, R.E.; Gozani, T.; Seher, C.C.

    1988-01-01

    In 1986 we presented a rationale for the detection of bulk explosives based on nuclear techniques that addressed the requirements of civil aviation security in the airport environment. Since then, efforts have intensified to implement a system based on thermal neutron activation (TNA), with new work developing in fast neutron and energetic photon reactions. In this paper we will describe these techniques and present new results from laboratory and airport testing. Based on preliminary results, we contended in our earlier paper that nuclear-based techniques did provide sufficiently penetrating probes and distinguishable detectable reaction products to achieve the FAA operational goals; new data have supported this contention. The status of nuclear-based techniques for the detection of bulk explosives presently under investigation by the US Federal Aviation Administration (FAA) is reviewed. These include thermal neutron activation (TNA), fast neutron activation (FNA), the associated particle technique, nuclear resonance absorption, and photoneutron activation. The results of comprehensive airport testing of the TNA system performed during 1987-88 are summarized. From a technical point of view, nuclear-based techniques now represent the most comprehensive and feasible approach for meeting the operational criteria of detection, false alarms, and throughput. 9 refs., 5 figs., 2 tabs.

  10. Analytical detection techniques for droplet microfluidics--a review.

    Science.gov (United States)

    Zhu, Ying; Fang, Qun

    2013-07-17

    In the last decade, droplet-based microfluidics has undergone rapid progress in the fields of single-cell analysis, digital PCR, protein crystallization and high throughput screening. It has been proved to be a promising platform for performing chemical and biological experiments with ultra-small volumes (picoliter to nanoliter) and ultra-high throughput. The ability to analyze the content in droplet qualitatively and quantitatively is playing an increasing role in the development and application of droplet-based microfluidic systems. In this review, we summarized the analytical detection techniques used in droplet systems and discussed the advantage and disadvantage of each technique through its application. The analytical techniques mentioned in this paper include bright-field microscopy, fluorescence microscopy, laser induced fluorescence, Raman spectroscopy, electrochemistry, capillary electrophoresis, mass spectrometry, nuclear magnetic resonance spectroscopy, absorption detection, chemiluminescence, and sample pretreatment techniques. The importance of analytical detection techniques in enabling new applications is highlighted. We also discuss the future development direction of analytical detection techniques for droplet-based microfluidic systems.

  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. 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...

  13. Comparative Study of Various Techniques on Outlier Detection

    Directory of Open Access Journals (Sweden)

    K, Varma Mamta and Rajesh Nigam

    2011-08-01

    Full Text Available Diverse patterns from web data, commonly referred to as web outliers or exceptional cases or noise; exist in many real-world databases. Detection of such outliers is important for numerous applications, such as detecting criminal activities in E-commerce. Outliers are data objects with different characteristics compared to other data objects. Formal definition of outliers is given by D.Hawkins. as “An Outlier is an observation that deviates so much from other observations so that it arouses suspicion that it is generated by a different mechanism”. Detection of such outliers (outlier mining is important for numerous applications, such as detecting criminal activities in E-commerce, video surveillance, weather prediction, intrusion detection and pharmaceutical research. This paper has focus on comparative study of various techniques on Outlier Detection.

  14. A review of techniques for detecting Huanglongbing (greening) in citrus.

    Science.gov (United States)

    Arredondo Valdés, Roberto; Delgado Ortiz, Juan C; Beltrán Beache, Mariana; Anguiano Cabello, Julia; Cerna Chávez, Ernesto; Rodríguez Pagaza, Yolanda; Ochoa Fuentes, Yisa M

    2016-10-01

    Huanglongbing (HLB) is the most destructive disease of citrus worldwide. Monitoring of health and detection of diseases in trees is critical for sustainable agriculture. HLB symptoms are virtually the same wherever the disease occurs. The disease is caused by Candidatus Liberibacter spp., vectored by the psyllids Diaphorina citri Kuwayama and Trioza erytreae. Electron microscopy was the first technique used for HLB detection. Nowadays, scientists are working on the development of new techniques for a rapid HLB detection, as there is no sensor commercially accessible for real-time assessment of health conditions in trees. Currently, the most widely used mechanism for monitoring HLB is exploration, which is an expensive, labor-intensive, and time-consuming process. Molecular techniques such as polymerase chain reaction are used for the identification of HLB disease, which requires detailed sampling and processing procedures. Furthermore, investigations are ongoing in spectroscopic and imaging techniques, profiling of plant volatile organic compounds, and isothermal amplification. This study recognizes the need for developing a rapid, cost-effective, and reliable health-monitoring sensor that would facilitate advancements in HLB disease detection. This paper compares the benefits and limitations of these potential methods for HLB detection.

  15. Study on measurement technique for sodium aerosols based on laser induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ohtaka, Masahiko; Hayashida, Hitoshi [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center

    2003-03-01

    Detection of small-scale sodium leak in its early stage is effective for enhancing fast reactor safety. Feasibility of the measuring technique for sodium aerosols based on LIBS was assessed. The technique is expected to enhance performance on high discrimination for the sodium aerosols with an equivalent detection limit of conventional small sodium leak detectors. Experiments using sodium aerosols were performed in order to design a measuring system and to study on some basic measuring performances. The results show the LIBS technique is feasible as a small sodium leak detector. (author)

  16. Development of Techniques for Trace Gas Detection in Breath

    OpenAIRE

    2012-01-01

    This thesis aims to investigate the possibility of developing spectroscopic techniques for trace gas detection, with particular emphasis on their applicability to breath analysis and medical diagnostics. Whilst key breath molecules such as methane and carbon dioxide will feature throughout this work, the focus of the research is on the detection of breath acetone, a molecule strongly linked with the diabetic condition. Preliminary studies into the suitability of cavity enhanced absorption...

  17. Comparison between different decorrelation techniques in vital sign detection

    Directory of Open Access Journals (Sweden)

    A. Dell'Aversano

    2016-09-01

    Full Text Available The problem of detecting the breath activities of a human subject is addressed. A CW signal is used to probe the scene and the MUSIC algorithm is exploited to detect frequency doppler modulation introduced by chest movements. For this particular measurement configuration, the correlation matrix results rank deficient. In order to restore the rank, two decorrelation techniques are compared by exploiting numerical data.

  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. 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.

  20. A Novel Technique to Detect EGFR Mutations in Lung Cancer

    Directory of Open Access Journals (Sweden)

    Yuanbin Liu

    2016-05-01

    Full Text Available Epidermal growth factor receptor (EGFR gene mutations occur in multiple human cancers; therefore, the detection of EGFR mutations could lead to early cancer diagnosis. This study describes a novel EGFR mutation detection technique. Compared to direct DNA sequencing detection methods, this method is based on allele-specific amplification (ASA, recombinase polymerase amplification (RPA, peptide nucleic acid (PNA, and SYBR Green I (SYBR, referred to as the AS-RPA-PNA-SYBR (ARPS system. The principle of this technique is based on three continuous steps: ASA or ASA combined with PNA to prevent non-target sequence amplification (even single nucleotide polymorphisms, SNPs, the rapid amplification advantage of RPA, and appropriate SYBR Green I detection (the samples harboring EGFR mutations show a green signal. Using this method, the EGFR 19Del(2 mutation was detected in 5 min, while the EGFR L858R mutation was detected in 10 min. In this study, the detection of EGFR mutations in clinical samples using the ARPS system was compatible with that determined by polymerase chain reaction (PCR and DNA sequencing methods. Thus, this newly developed methodology that uses the ARPS system with appropriate primer sets is a rapid, reliable, and practical way to assess EGFR mutations in clinical samples.

  1. Advanced Doppler radar physiological sensing technique for drone detection

    Science.gov (United States)

    Yoon, Ji Hwan; Xu, Hao; Garcia Carrillo, Luis R.

    2017-05-01

    A 24 GHz medium-range human detecting sensor, using the Doppler Radar Physiological Sensing (DRPS) technique, which can also detect unmanned aerial vehicles (UAVs or drones), is currently under development for potential rescue and anti-drone applications. DRPS systems are specifically designed to remotely monitor small movements of non-metallic human tissues such as cardiopulmonary activity and respiration. Once optimized, the unique capabilities of DRPS could be used to detect UAVs. Initial measurements have shown that DRPS technology is able to detect moving and stationary humans, as well as largely non-metallic multi-rotor drone helicopters. Further data processing will incorporate pattern recognition to detect multiple signatures (motor vibration and hovering patterns) of UAVs.

  2. Outlier Detection Techniques For Wireless Sensor Networks: A Survey

    NARCIS (Netherlands)

    Zhang, Y.; Meratnia, Nirvana; Havinga, Paul J.M.

    2008-01-01

    In the field of wireless sensor networks, measurements that significantly deviate from the normal pattern of sensed data are considered as outliers. The potential sources of outliers include noise and errors, events, and malicious attacks on the network. Traditional outlier detection techniques are

  3. Detection of Damage in Hydraulic Components by Acoustic Emission Techniques.

    Science.gov (United States)

    1984-04-01

    The narrow-band spectrum of the A.E. signal 61 ,o r r. VV W ’ -r from 0 - 100 KHz was obtained using a spectrum aralyzer. he flujo temperature and...leaks of gases and of liquids create high frequency sounds as well. The greatest single difficulty in -: implementing this kind of test procedure is

  4. Detection of Cracks in Concrete Structure Using Microwave Imaging Technique

    Directory of Open Access Journals (Sweden)

    E. A. Jiya

    2016-01-01

    Full Text Available Cracks in concrete or cement based materials present a great threat to any civil structures; they are very dangerous and have caused a lot of destruction and damage. Even small cracks that look insignificant can grow and may eventually lead to severe structural failure. Besides manual inspection that is ineffective and time-consuming, several nondestructive evaluation techniques have been used for crack detection such as ultrasonic technique, vibration technique, and strain-based technique; however, some of the sensors used are either too large in size or limited in resolution. A high resolution microwave imaging technique with ultrawideband signal for crack detection in concrete structures is proposed. A combination of the delay-and-sum beamformer with full-view mounted antennas constitutes the image reconstruction algorithm. Various anomaly scenarios in cement bricks were simulated using FDTD, constructed, and measured in the lab. The reconstructed images showed a high similarity between the simulation and the experiment with a resolution of λ/14 which enables a detection of cracks as small as 5 mm in size.

  5. 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.

  6. Crack detection and sizing technique by ultrasonic and electromagnetic methods

    Energy Technology Data Exchange (ETDEWEB)

    Komura, Ichiro E-mail: ichiro.komura@toshiba.co.jp; Hirasawa, Taiji; Nagai, Satoshi; Takabayashi, Jun-ichi; Naruse, Katsuhiko

    2001-06-01

    Improvements in defect detection and sizing capabilities for non-destructive inspection techniques have been required in order to ensure the reliable operation and life extension of nuclear power plants. For the volumetric inspection, the phased array UT technique has superior capabilities for beam steering and focusing to objective regions, and real-time B-scan imaging without mechanical scanning. In contrast to the conventional UT method, high-speed inspection is realized by the unique feature of the phased array technique. A 256-channel array system has developed for the inspection of weldment of BWR internal components such as core shrouds. The TOFD crack sizing technique also can be applied using this system. For the surface inspection, potential drop techniques and eddy current techniques have been improved, which combined the theoretical analysis. These techniques have the crack sizing capability for surface breaking cracks to which UT method is difficult to apply. This paper provides the recent progress of these phased array and electromagnetic inspection techniques.

  7. 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.

  8. 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

    the vicinity of the moderator pot was driving the MSLD out of range. Since it was very difficult to locate the leak by Tracer Probe Method, some other technique was ventured to solve the problem of leak location. Finally, it was possible to locate the leak by observing the change in Helium background reading of MSLD during masking/unmasking of the welded joints. This paper, in general describes the design and leak testing aspects of cryogenic components of Cold Neutron Source and in particular, the problems and solutions for leak testing of transfer lines and moderator pot.

  9. 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

    moderator pot was driving the MSLD out of range. Since it was very difficult to locate the leak by Tracer Probe Method, some other technique was ventured to solve the problem of leak location. Finally, it was possible to locate the leak by observing the change in Helium background reading of MSLD during masking/unmasking of the welded joints. This paper, in general describes the design and leak testing aspects of cryogenic components of Cold Neutron Source and in particular, the problems and solutions for leak testing of transfer lines and moderator pot.

  10. Evaluation of Non-Volcanic Tremor Detection Techniques

    Science.gov (United States)

    Sit, S. M.; Brudzinski, M. R.; Kao, H.

    2009-12-01

    Non-volcanic tremor (NVT) is a subduction zone process often associated with the transition from stick-slip to stable sliding on the plate interface. In Northern Cascadia, NVT episodes lasting multiple weeks have been correlated spatially and temporally with slow slip episodes at a regular recurrence interval of 15±2 months. However, NVT across the entire Cascadia margin varies widely in recurrence and duration, while still other subduction zones (Japan, Mexico) observe separate cases of tremor and GPS-detected slip. Multiple identification and location techniques exist, but we will focus on techniques that can identify NVT at single stations to accommodate searching outside a dense network of instruments. This study evaluates these techniques in several regions along the entire Cascadia margin and in the Oaxaca segment of the Middle America Subduction Zone. Tremor signals are collected from a mixture of seismometers including those of temporary deployments targeting NVT, the EarthScope Transportable Array, the Canadian National Seismograph Network, and a few other regional networks that span the subduction zones. We compare existing techniques that scan moving averages, scintillation index, and hourly mean amplitudes with a new tremor frequency scanning technique that bandpass filters seismic data into three categories, 10-15 Hz, 2-5 Hz, and 0.2-0.5 Hz, where we expect prominent signals from microseismicity, NVT, and surface waves, respectively. Applying these techniques to episodes over the last few years finds that each technique can identify large, multi-week tremor events associated with GPS recorded slow slip. However, different techniques result in different totals of tremor hours detected per episode, as well as variable numbers of additional smaller episodes identified. Based on previous research that finds the amount of tremor correlated to the amount of slip from geodetic inversions, we are working towards a consensus single station approach that is

  11. Ion cyclotron resonance detection techniques at TRIGA-TRAP

    Energy Technology Data Exchange (ETDEWEB)

    Knuth, K.; Eberhardt, K.; Ketelaer, J. [Johannes Gutenberg-Universitaet, Mainz (Germany); Beyer, T.; Blaum, K. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Ruprecht-Karls-Universitaet, Heidelberg (Germany); Block, M.; Herfurth, F. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Eibach, M.; Smorra, C. [Johannes Gutenberg-Universitaet, Mainz (Germany); Ruprecht-Karls-Universitaet, Heidelberg (Germany); Nagy, S. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

    2010-07-01

    In Penning trap mass spectrometry the mass of stored ions is obtained via a determination of the cyclotron frequency ({nu}{sub c}=qB/(2 {pi} m)), for which two different techniques are available. The destructive time-of-flight ion cyclotron resonance (TOF-ICR) technique, based on the measurement of the flight time of excited ions, is the established method for measurements on short-lived radionuclides. It is not ideally suited for rarely produced ion species, since typically some hundred ions are required for a single resonance spectrum. At the Penning trap mass spectrometer TRIGA-TRAP therefore a non-destructive narrow-band Fourier transform ion cyclotron resonance (FT-ICR) detection system is being developed. It is based on the detection of the image currents induced by the stored ions in the trap electrodes and will ultimately reach single ion sensitivity. TRIGA-TRAP also features broad-band FT-ICR detection for the coarse identification of the trap content. Additionally, the TOF-ICR detection system has been recently improved to utilize the Ramsey excitation technique to gain in precision, and the position information of the ion impact to further suppress background events in the final time-of-flight spectrum.

  12. Skin artifact removal technique for breast cancer radar detection

    Science.gov (United States)

    Caorsi, S.; Lenzi, C.

    2016-06-01

    In this paper we propose a new model-based skin artifact cleaning technique with the aim to remove skin reflections with good effectiveness, without introducing significant signal distortions, and without assuming a priori information on the real structure of the breast. The reference cleaning model, constituted by a two-layer geometry skin-adipose tissue, is oriented to all the ultrawideband radar methods able to detect the tumor starting by the knowledge of each trace recorded around the breast. All the radar signal measurements were simulated by using realistic breast models derived from the University of Wisconsin computational electromagnetic laboratory database and the finite difference time domain (FDTD)-based open source software GprMax. First, we have searched for the best configuration for the reference cleaning model with the aim to minimize the distortions introduced on the radar signal. Second, the performance of the proposed cleaning technique has been assessed by using a breast cancer radar detection technique based on the use of artificial neural network (ANN). In order to minimize the signal distortions, we found that it was necessary to use the real skin thickness and the static Debye parameters of both skin and adipose tissue. In such a case the ANN-based radar approach was able to detect the tumor with an accuracy of 87%. By extending the performance assessment also to the case when only average standard values are used to characterize the reference cleaning model, the detection accuracy was of 84%.

  13. Study and Comparison of Various Techniques of Image Edge Detection

    Directory of Open Access Journals (Sweden)

    Gurjeet Singh

    2014-03-01

    Full Text Available An edge may be defined as a set of connected pixels that forms a boundary between two disjoints regions. Image Edge detection reduces the amount of data and filters out useless information, while preserving the important structural properties in an image. Edge detection plays an important role in digital image processing and practical aspects of our daily life. In this paper we studied various edge detection techniques as Prewitt, Robert, Sobel, LoG and Canny operators. On comparing them we conclude that canny edge detector performs better than all other edge detectors on various aspects such as it is adaptive in nature, performs better for noisy image, gives sharp edges, low probability of detecting false edges.

  14. Target Detection: Remote Sensing Techniques for Defence Applications

    Directory of Open Access Journals (Sweden)

    B. B. Chaudhuri

    1995-10-01

    Full Text Available The tremendous development in remote sensing technology in the recent past has opened up new challenges in defence applications. On important area of such applications is in target detection. This paper describes both classical and newly developed approaches to detect the targets by using remotely-sensed digital images. The classical approach includes statistical classification methods and image processing techniques. The new approach deals with a relatively new sensor technology, namely, synthetic aperture radar (SAR systems and fast developing tools, like neural networks and multisource data integration for analysis and interpretation. With SAR images, it is possible to detect targets or features of a target that is otherwise not possible. Neural networks and multisource data integration tools also have a great potential in analysing and interpreting remote sensing data for target detection.

  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. Detection of immobilized amplicons by ELISA-like techniques.

    Science.gov (United States)

    Oroskar, A A; Rasmussen, S E; Rasmussen, H N; Rasmussen, S R; Sullivan, B M; Johansson, A

    1996-09-01

    The NucleoLink surface is a physically modified, thermostable, optically clear resin. It allows the covalent binding of 5'-phosphorylated oligonucleotides. Target DNA amplification by polymerase chain reaction (PCR) is accomplished by asymmetric amplification on the covalently immobilized primer that develops into immobilized amplicons. A DNA fragment of bovine leukemia virus is used as a model system for the detection of immobilized amplicons by ELISA-like techniques. Covalently bound oligonucleotides are also utilized as capture probe in the hybridization-based signal amplification for detection of an infectious organism.

  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. A novel inductive technique for microcantilever displacement detection

    Institute of Scientific and Technical Information of China (English)

    Madhu; Santosh; K; Mutyala; Kody; Varahramyan

    2011-01-01

    A novel inductive technique for the detection of microcantilever displacement for sensing applications was presented.We highlight the basic structure and evaluate its characteristics with the aid of modeling and simulation.Results generated by numerical simulations using ANSOFT are compared with those obtained from an equivalent circuit model using PSPICE.There are indications that the sensitivity of the inductive cantilever is about one order of magnitude higher as compared to piezoresistive silicon can...

  3. A new imaging technique for detecting interstellar communications

    Science.gov (United States)

    Vallerga, John; Welsh, Barry; Kotze, Marissa; Siegmund, Oswald

    2017-01-01

    We report on a unique detection methodology using the Berkeley Visible Image Tube (BVIT) mounted on the 10m Southern African Large Telescope (SALT) to search for laser pulses originating in communications from advanced extraterrestrial (ET) civilizations residing on nearby Earth-like planets located within their habitability zones. The detection technique assumes that ET communicates through high powered pulsed lasers with pulse durations on the order of 5 nanoseconds, the signals thereby being brighter than that of the host star within this very short period of time. Our technique turns down the gain of the optically sensitive photon counting microchannel plate detector such that ~30 photons are required in a 5ns window to generate an imaged event. Picking a priori targets with planets in the habitable zone substantially reduces the false alarm rate. Interplanetary communication by optical masers was first postulated by Schwartz and Townes in 1961. Under the assumption that ET has access to a 10 m class telescope operated as a transmitter then we could detect lasers with a similar power to that of the Livermore Laboratory laser (~1.8Mj per pulse), to a distance of ~ 1000 pc. In this talk we present the results of 2400 seconds of BVIT observations on the SALT of the star Wolf 1061, which is known to harbor an Earth-sized exoplanet located in the habitability zone. At this distance (4.3 pc), BVIT on SALT could detect a 48 joule per pulse laser, now commercially available as tabletop devices.

  4. Ultrasonic Techniques for Baseline-Free Damage Detection in Structures

    Science.gov (United States)

    Dutta, Debaditya

    This research presents ultrasonic techniques for baseline-free damage detection in structures in the context of structural health monitoring (SHM). Conventional SHM methods compare signals obtained from the pristine condition of a structure (baseline signals) with those from the current state, and relate certain changes in the signal characteristics to damage. While this approach has been successful in the laboratory, there are certain drawbacks of depending on baseline signals in real field applications. Data from the pristine condition are not available for most existing structures. Even if they are available, operational and environmental variations tend to mask the effect of damage on the signal characteristics. Most important, baseline measurements may become meaningless while assessing the condition of a structure after an extreme event such as an earthquake or a hurricane. Such events may destroy the sensors themselves and require installation of new sensors at different locations on the structure. Baseline-free structural damage detection can broaden the scope of SHM in the scenarios described above. A detailed discussion on the philosophy of baseline-free damage detection is provided in Chapter 1. Following this discussion, the research questions are formulated. The organization of this document and the major contributions of this research are also listed in this chapter. Chapter 2 describes a fully automated baseline-free technique for notch and crack detection in plates using a collocated pair of piezoelectric wafer transducers for measuring ultrasonic signals. Signal component corresponding to the damage induced mode-converted Lamb waves is extracted by processing the originally measured ultrasonic signals. The damage index is computed as a function of this mode-converted Lamb wave signal component. An over-determined system of Lamb wave measurements is used to find a least-square estimate of the measurement errors. This error estimate serves as the

  5. Object detection techniques applied on mobile robot semantic navigation.

    Science.gov (United States)

    Astua, Carlos; Barber, Ramon; Crespo, Jonathan; Jardon, Alberto

    2014-04-11

    The future of robotics predicts that robots will integrate themselves more every day with human beings and their environments. To achieve this integration, robots need to acquire information about the environment and its objects. There is a big need for algorithms to provide robots with these sort of skills, from the location where objects are needed to accomplish a task up to where these objects are considered as information about the environment. This paper presents a way to provide mobile robots with the ability-skill to detect objets for semantic navigation. This paper aims to use current trends in robotics and at the same time, that can be exported to other platforms. Two methods to detect objects are proposed, contour detection and a descriptor based technique, and both of them are combined to overcome their respective limitations. Finally, the code is tested on a real robot, to prove its accuracy and efficiency.

  6. Object Detection Techniques Applied on Mobile Robot Semantic Navigation

    Directory of Open Access Journals (Sweden)

    Carlos Astua

    2014-04-01

    Full Text Available The future of robotics predicts that robots will integrate themselves more every day with human beings and their environments. To achieve this integration, robots need to acquire information about the environment and its objects. There is a big need for algorithms to provide robots with these sort of skills, from the location where objects are needed to accomplish a task up to where these objects are considered as information about the environment. This paper presents a way to provide mobile robots with the ability-skill to detect objets for semantic navigation. This paper aims to use current trends in robotics and at the same time, that can be exported to other platforms. Two methods to detect objects are proposed, contour detection and a descriptor based technique, and both of them are combined to overcome their respective limitations. Finally, the code is tested on a real robot, to prove its accuracy and efficiency.

  7. Early Oscillation Detection Technique for Hybrid DC/DC Converters

    Science.gov (United States)

    Wang, Bright L.

    2011-01-01

    Oscillation or instability is a situation that must be avoided for reliable hybrid DC/DC converters. A real-time electronics measurement technique was developed to detect catastrophic oscillations at early stages for hybrid DC/DC converters. It is capable of identifying low-level oscillation and determining the degree of the oscillation at a unique frequency for every individual model of the converters without disturbing their normal operations. This technique is specially developed for space-used hybrid DC/DC converters, but it is also suitable for most of commercial and military switching-mode power supplies. This is a weak-electronic-signal detection technique to detect hybrid DC/DC converter oscillation presented as a specific noise signal at power input pins. It is based on principles of feedback control loop oscillation and RF signal modulations, and is realized by using signal power spectral analysis. On the power spectrum, a channel power amplitude at characteristic frequency (CPcf) and a channel power amplitude at switching frequency (CPsw) are chosen as oscillation level indicators. If the converter is stable, the CPcf is a very small pulse and the CPsw is a larger, clear, single pulse. At early stage of oscillation, the CPcf increases to a certain level and the CPsw shows a small pair of sideband pulses around it. If the converter oscillates, the CPcf reaches to a higher level and the CPsw shows more high-level sideband pulses. A comprehensive stability index (CSI) is adopted as a quantitative measure to accurately assign a degree of stability to a specific DC/DC converter. The CSI is a ratio of normal and abnormal power spectral density, and can be calculated using specified and measured CPcf and CPsw data. The novel and unique feature of this technique is the use of power channel amplitudes at characteristic frequency and switching frequency to evaluate stability and identify oscillations at an early stage without interfering with a DC/DC converter s

  8. Technique for rapid detection of phthalates in water and beverages

    KAUST Repository

    Zia, Asif I.

    2013-05-01

    The teratogenic and carcinogenic effects of phthalate esters on living beings are proven in toxicology studies. These ubiquitous food and environmental pollutants pose a great danger to the human race due to their extraordinary use as a plasticizer in the consumer product industry. Contemporary detection techniques used for phthalates require a high level of skills, expensive equipment and longer analysis time than the presented technique. Presented research work introduces a real time non-invasive detection technique using a new type of silicon substrate based planar interdigital (ID) sensor fabricated on basis of thin film micro-electromechanical system (MEMS) semiconductor device fabrication technology. Electrochemical impedance spectroscopy (EIS) was used in conjunction with the fabricated sensor to detect phthalates in deionized water. Various concentrations of di(2-ethylhexyl) phthalate (DEHP) as low as 2 ppb to a higher level of 2 ppm in deionized water were detected distinctively using new planar ID sensor based EIS sensing system. Dip testing method was used to obtain the conductance and dielectric properties of the bulk samples. Parylene C polymer coating was used as a passivation layer on the surface of the fabricated sensor to reduce the influence of Faradaic currents. In addition, inherent dielectric properties of the coating enhanced the sensitivity of the capacitive type sensor. Electrochemical spectrum analysis algorithm was used to model experimentally observed impedance spectrum to deduce constant phase element (CPE) equivalent circuit to analyse the kinetic processes taking place inside the electrochemical cell. Curve fitting technique was used to extract the values of the circuit components and explain experimental results on theoretical grounds. The sensor performance was tested by adding DEHP to an energy drink at concentrations above and below the minimal risk level (MRL) limit set by the ATSDR (Agency for Toxic Substances & Disease Registry

  9. 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

  10. 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.

  11. Outlier Detection Techniques for SQL and ETL Tuning

    CERN Document Server

    Goswami, Saptarsi; Chakrabarti, Amlan

    2012-01-01

    RDBMS is the heart for both OLTP and OLAP types of applications. For both types of applications thousands of queries expressed in terms of SQL are executed on daily basis. All the commercial DBMS engines capture various attributes in system tables about these executed queries. These queries need to conform to best practices and need to be tuned to ensure optimal performance. While we use checklists, often tools to enforce the same, a black box technique on the queries for profiling, outlier detection is not employed for a summary level understanding. This is the motivation of the paper, as this not only points out to inefficiencies built in the system, but also has the potential to point evolving best practices and inappropriate usage. Certainly this can reduce latency in information flow and optimal utilization of hardware and software capacity. In this paper we start with formulating the problem. We explore four outlier detection techniques. We apply these techniques over rich corpora of production queries ...

  12. Detection of cavitation vortex in hydraulic turbines using acoustic techniques

    Science.gov (United States)

    Candel, I.; Bunea, F.; Dunca, G.; Bucur, D. M.; Ioana, C.; Reeb, B.; Ciocan, G. D.

    2014-03-01

    Cavitation phenomena are known for their destructive capacity in hydraulic machineries and are caused by the pressure decrease followed by an implosion when the cavitation bubbles find an adverse pressure gradient. A helical vortex appears in the turbine diffuser cone at partial flow rate operation and can be cavitating in its core. Cavity volumes and vortex frequencies vary with the under-pressure level. If the vortex frequency comes close to one of the eigen frequencies of the turbine, a resonance phenomenon may occur, the unsteady fluctuations can be amplified and lead to important turbine and hydraulic circuit damage. Conventional cavitation vortex detection techniques are based on passive devices (pressure sensors or accelerometers). Limited sensor bandwidths and low frequency response limit the vortex detection and characterization information provided by the passive techniques. In order to go beyond these techniques and develop a new active one that will remove these drawbacks, previous work in the field has shown that techniques based on acoustic signals using adapted signal content to a particular hydraulic situation, can be more robust and accurate. The cavitation vortex effects in the water flow profile downstream hydraulic turbines runner are responsible for signal content modifications. Basic signal techniques use narrow band signals traveling inside the flow from an emitting transducer to a receiving one (active sensors). Emissions of wide band signals in the flow during the apparition and development of the vortex embeds changes in the received signals. Signal processing methods are used to estimate the cavitation apparition and evolution. Tests done in a reduced scale facility showed that due to the increasing flow rate, the signal -- vortex interaction is seen as modifications on the received signal's high order statistics and bandwidth. Wide band acoustic transducers have a higher dynamic range over mechanical elements; the system's reaction time

  13. Fault detection in rotor bearing systems using time frequency techniques

    Science.gov (United States)

    Chandra, N. Harish; Sekhar, A. S.

    2016-05-01

    Faults such as misalignment, rotor cracks and rotor to stator rub can exist collectively in rotor bearing systems. It is an important task for rotor dynamic personnel to monitor and detect faults in rotating machinery. In this paper, the rotor startup vibrations are utilized to solve the fault identification problem using time frequency techniques. Numerical simulations are performed through finite element analysis of the rotor bearing system with individual and collective combinations of faults as mentioned above. Three signal processing tools namely Short Time Fourier Transform (STFT), Continuous Wavelet Transform (CWT) and Hilbert Huang Transform (HHT) are compared to evaluate their detection performance. The effect of addition of Signal to Noise ratio (SNR) on three time frequency techniques is presented. The comparative study is focused towards detecting the least possible level of the fault induced and the computational time consumed. The computation time consumed by HHT is very less when compared to CWT based diagnosis. However, for noisy data CWT is more preferred over HHT. To identify fault characteristics using wavelets a procedure to adjust resolution of the mother wavelet is presented in detail. Experiments are conducted to obtain the run-up data of a rotor bearing setup for diagnosis of shaft misalignment and rotor stator rubbing faults.

  14. FEM Techniques for High Stress Detection in Accelerated Fatigue Simulation

    Science.gov (United States)

    Veltri, M.

    2016-09-01

    This work presents the theory and a numerical validation study in support to a novel method for a priori identification of fatigue critical regions, with the aim to accelerate durability design in large FEM problems. The investigation is placed in the context of modern full-body structural durability analysis, where a computationally intensive dynamic solution could be required to identify areas with potential for fatigue damage initiation. The early detection of fatigue critical areas can drive a simplification of the problem size, leading to sensible improvement in solution time and model handling while allowing processing of the critical areas in higher detail. The proposed technique is applied to a real life industrial case in a comparative assessment with established practices. Synthetic damage prediction quantification and visualization techniques allow for a quick and efficient comparison between methods, outlining potential application benefits and boundaries.

  15. Electrochemical techniques for subsecond neurotransmitter detection in live rodents.

    Science.gov (United States)

    Hascup, Kevin N; Hascup, Erin R

    2014-08-01

    Alterations in neurotransmission have been implicated in numerous neurodegenerative and neuropsychiatric disorders, including Alzheimer disease, Parkinson disease, epilepsy, and schizophrenia. Unfortunately, few techniques support the measurement of real-time changes in neurotransmitter levels over multiple days, as is essential for ethologic and pharmacodynamic testing. Microdialysis is commonly used for these research paradigms, but its poor temporal and spatial resolution make this technique inadequate for measuring the rapid dynamics (milliseconds to seconds) of fast signaling neurotransmitters, such as glutamate and acetylcholine. Enzymatic microelectrode arrays (biosensors) coupled with electrochemical recording techniques have demonstrated fast temporal resolution (less than 1 s), excellent spatial resolution (micron-scale), low detection limits (≤200 nM), and minimal damage (50 to 100 μm) to surrounding brain tissue. Here we discuss the benefits, methods, and animal welfare considerations of using platinum microelectrodes on a ceramic substrate for enzyme-based electrochemical recording techniques for real-time in vivo neurotransmitter recordings in both anesthetized and awake, freely moving rodents.

  16. 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.

  17. Detecting Distributed Denial of Service Attacks Using Data Mining Techniques

    Directory of Open Access Journals (Sweden)

    Mouhammd Alkasassbeh

    2016-01-01

    Full Text Available Users and organizations find it continuously challenging to deal with distributed denial of service (DDoS attacks. . The security engineer works to keep a service available at all times by dealing with intruder attacks. The intrusion-detection system (IDS is one of the solutions to detecting and classifying any anomalous behavior. The IDS system should always be updated with the latest intruder attack deterrents to preserve the confidentiality, integrity and availability of the service. In this paper, a new dataset is collected because there were no common data sets that contain modern DDoS attacks in different network layers, such as (SIDDoS, HTTP Flood. This work incorporates three well-known classification techniques: Multilayer Perceptron (MLP, Naïve Bayes and Random Forest. The experimental results show that MLP achieved the highest accuracy rate (98.63%.

  18. Research on radon detecting technique for locating inaccessible underground heatings

    Institute of Scientific and Technical Information of China (English)

    XIE Jun; XUE Sheng; WANG Gang

    2011-01-01

    The identification of the exact location of the heatings that occur in often inaccessible locations several hundred meters deep in goaf areas is a key to allowing effective control measures to be taken.Radon technique provides the only solution for remotely locating underground sponcom from surface.The results of Chaili mine indicated that a total area of 66 000 m2 has been surveyed and exact locations of spontaneous combustion have been detected.This has enabled the successful implementation of various control measures against spontaneous combustion.

  19. DNA microarray technique for detecting food-borne pathogens

    Directory of Open Access Journals (Sweden)

    Xing GAO

    2012-08-01

    Full Text Available Objective To study the application of DNA microarray technique for screening and identifying multiple food-borne pathogens. Methods The oligonucleotide probes were designed by Clustal X and Oligo 6.0 at the conserved regions of specific genes of multiple food-borne pathogens, and then were validated by bioinformatic analyses. The 5' end of each probe was modified by amino-group and 10 Poly-T, and the optimized probes were synthesized and spotted on aldehyde-coated slides. The bacteria DNA template incubated with Klenow enzyme was amplified by arbitrarily primed PCR, and PCR products incorporated into Aminoallyl-dUTP were coupled with fluorescent dye. After hybridization of the purified PCR products with DNA microarray, the hybridization image and fluorescence intensity analysis was acquired by ScanArray and GenePix Pro 5.1 software. A series of detection conditions such as arbitrarily primed PCR and microarray hybridization were optimized. The specificity of this approach was evaluated by 16 different bacteria DNA, and the sensitivity and reproducibility were verified by 4 food-borne pathogens DNA. The samples of multiple bacteria DNA and simulated water samples of Shigella dysenteriae were detected. Results Nine different food-borne bacteria were successfully discriminated under the same condition. The sensitivity of genomic DNA was 102 -103pg/ μl, and the coefficient of variation (CV of the reproducibility of assay was less than 15%. The corresponding specific hybridization maps of the multiple bacteria DNA samples were obtained, and the detection limit of simulated water sample of Shigella dysenteriae was 3.54×105cfu/ml. Conclusions The DNA microarray detection system based on arbitrarily primed PCR can be employed for effective detection of multiple food-borne pathogens, and this assay may offer a new method for high-throughput platform for detecting bacteria.

  20. 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

  1. 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.

  2. Robust satellite techniques for oil spill detection and monitoring

    Science.gov (United States)

    Casciello, D.; Pergola, N.; Tramutoli, V.

    Discharge of oil into the sea is one of the most dangerous, among technological hazards, for the maritime environment. In the last years maritime transport and exploitation of marine resources continued to increase; as a result, tanker accidents are nowadays increasingly frequent, continuously menacing the maritime security and safety. Satellite remote sensing could contribute in multiple ways, in particular for what concerns early warning and real-time (or near real-time) monitoring. Several satellite techniques exist, mainly based on the use of SAR (Synthetic Aperture Radar) technology, which are able to recognise, with sufficient accuracy, oil spills discharged into the sea. Unfortunately, such methods cannot be profitably used for real-time detection, because of the low observational frequency assured by present satellite platforms carrying SAR sensors (the mean repetition rate is something like 30 days). On the other hand, potential of optical sensors aboard meteorological satellites, was not yet fully exploited and no reliable techniques have been developed until now for this purpose. Main limit of proposed techniques can be found in the ``fixed threshold'' approach which makes such techniques difficult to implement without operator supervision and, generally, without an independent information on the oil spill presence that could drive the choice of the best threshold. A different methodological approach (RAT, Robust AVHRR Techniques) proposed by Tramutoli (1998) and already successfully applied to several natural and environmental emergencies related to volcanic eruptions, forest fires and seismic activity. In this paper its extension to near real-time detection and monitoring of oil spills by means of NOAA-AVHRR (Advanced Very High Resolution Radiometer) records will be described. Briefly, RAT approach is an automatic change-detection scheme that considers a satellite image as a space-time process, described at each place (x,y) and time t, by the value of

  3. Postprocessing techniques of CT colonography in detection of colorectal carcinoma

    Institute of Scientific and Technical Information of China (English)

    Ming-Yue Luo; Hong Shan; Li-Qing Yao; Kang-Rong Zhou; Wen-Wei Liang

    2004-01-01

    AIM: To evaluate the value of postprocessing techniques of CT colonography, including multiplanar reformation (MPR),virtual colonoscopy (VC), shaded surface display (SSD) and Raysum, in detection of colorectal carcinomas.METHODS: Sixty-four patients with colorectal carcinoma underwent volume scanning with spiral CT. MPR, VC, SSD and Raysum images were obtained by using four kinds of postprocessing techniques in workstation. The results were comparatively analyzed according to circumferential extent,lesion length and pathology pattern of colorectal carcinomas.All diagnoses were proved pathologically and surgically.RESULTS: The accuracy of circumferential extent of colorectal carcinoma determined by MPR, VC, SSD and Raysum was 100.0%, 82.8%, 79.7% and 79.7%,respectively. There was a significant statistical difference between MPR and VC. The consistent rate of lesion length was 89.1%, 76.6%, 95.3% and 100.0%, respectively.There was a statistical difference between VC and SSD.The accuracy of discriminating pathology pattern was 81.3%,92.2%, 71.9% and 71.9%, respectively. There was a statistical difference between VC and SSD. MPR could determine accurately the circumference of colorectal carcinoma, Raysum could determine the length of lesion more precisely than SSD, VC was helpful in discriminating pathology patterns.CONCLUSION: MPR, VC, SSD and Raysum have advantage and disadvantage in detection of colorectal carcinoma, use of these methods in combination can disclose the lesion more accurately.

  4. Application of Kalman Filtering Techniques for Microseismic Event Detection

    Science.gov (United States)

    Baziw, E.; Weir-Jones, I.

    - Microseismic monitoring systems are generally installed in areas of induced seismicity caused by human activity. Induced seismicity results from changes in the state of stress which may occur as a result of excavation within the rock mass in mining (i.e., rockbursts), and changes in hydrostatic pressures and rock temperatures (e.g., during fluid injection or extraction) in oil exploitation, dam construction or fluid disposal. Microseismic monitoring systems determine event locations and important source parameters such as attenuation, seismic moment, source radius, static stress drop, peak particle velocity and seismic energy. An essential part of the operation of a microseismic monitoring system is the reliable detection of microseismic events. In the absence of reliable, automated picking techniques, operators rely upon manual picking. This is time-consuming, costly and, in the presence of background noise, very prone to error. The techniques described in this paper not only permit the reliable identification of events in cluttered signal environments they have also enabled the authors to develop reliable automated event picking procedures. This opens the way to use microseismic monitoring as a cost-effective production/operations procedure. It has been the experience of the authors that in certain noisy environments, the seismic monitoring system may trigger on and subsequently acquire substantial quantities of erroneous data, due to the high energy content of the ambient noise. Digital filtering techniques need to be applied on the microseismic data so that the ambient noise is removed and event detection simplified. The monitoring of seismic acoustic emissions is a continuous, real-time process and it is desirable to implement digital filters which can also be designed in the time domain and in real-time such as the Kalman Filter. This paper presents a real-time Kalman Filter which removes the statistically describable background noise from the recorded

  5. Clinical Study of Acoustic Densitometry Technique in Detecting Atherosclerotic Plaque

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Objective: To investigate the effect of Quyu Xiaoban Capsule (祛瘀消斑, QYXB) on the regressive treatment of atherosclerosis (AS) with acoustic densitometry (AD) technique. Methods: Eighty patients with AS were randomly divided into two groups, trial group was treated with QYXB and conventional medicine, and control group was treated with conventional medicine alone. Normal arterial wall and different types of atherosclerotic plaques were detected with AD technique before treatment and 10 months later. Resuits: The corrected averages in intimal echo intensity (AIIc%) were elevated in both groups but without significant difference, AIIc% of fatty plaques were increased in both groups and the value after treatment was significantly higher than that of pre-treatment in the trial group (68.12±5.54 vs 61.43±5.37, P<0.05).The increment rate of AIIc% in trial group was significantly higher than that in control group (10.9±5.1% vs2.5±5.5%, P<0.05). Conclusion: QYXB can stabilize the atherosclerotic plaque by increasing its acoustic density. Acoustic densitometry technique can differentiate the different histological plaques and monitor the histological changes of plaques during treatment.

  6. Physiological techniques for detecting expiratory flow limitation during tidal breathing

    Directory of Open Access Journals (Sweden)

    N.G. Koulouris

    2011-09-01

    Full Text Available Patients with severe chronic obstructive pulmonary disease (COPD often exhale along the same flow–volume curve during quiet breathing as they do during the forced expiratory vital capacity manoeuvre, and this has been taken as an indicator of expiratory flow limitation at rest (EFLT. Therefore, EFLT, namely attainment of maximal expiratory flow during tidal expiration, occurs when an increase in transpulmonary pressure causes no increase in expiratory flow. EFLT leads to small airway injury and promotes dynamic pulmonary hyperinflation, with concurrent dyspnoea and exercise limitation. In fact, EFLT occurs commonly in COPD patients (mainly in Global Initiative for Chronic Obstructive Lung Disease III and IV stage, in whom the latter symptoms are common, but is not exclusive to COPD, since it can also be detected in other pulmonary and nonpulmonary diseases like asthma, acute respiratory distress syndrome, heart failure and obesity, etc. The existing up to date physiological techniques of assessing EFLT are reviewed in the present work. Among the currently available techniques, the negative expiratory pressure has been validated in a wide variety of settings and disorders. Consequently, it should be regarded as a simple, noninvasive, practical and accurate new technique.

  7. Ultrasonic techniques for the detection of discontinuities in aluminum foams

    Science.gov (United States)

    Katchadjian, Pablo; García, Alejandro; Brizuela, Jose; Camacho, Jorge; Álvarez-Arenas, Tomás Gómez; Chiné, Bruno; Mussi, Valerio

    2017-02-01

    Metal foams are interesting materials with many potential applications. They are characterized by a cellular structure, that is the metals or metal alloys foamed include gas voids in the material. Their particular lightweight structure and physical, chemical and mechanical properties make them suitable for a wide range of industrial applications in different sectors. For industrial applications, metal foams offer attractive combinations of low density, high stiffness to weight ratio, good energy absorption and vibration damping capacity that cannot be obtained with other materials. The control of the foaming process and the characterization of the metal foam are important issues in order to obtain a product with good properties and guarantee the quality of a mechanical component. The characterization and control of mechanical components and sandwich panels manufactured with metal foams require the assessment of the defects present in this material, like large pores or imperfections which are responsible of deteriorating the mechanical performance. Therefore, specific methods of non-destructive testing are required, both in the manufacturing process and during the life of the component. In this work, some ultrasonic transmission techniques developed for detection of defects associated with the manufacturing process of aluminum foams are proposed. These techniques were used on plates and structures of different thicknesses and geometries formed with this material. Ultrasonic transmission techniques were carried out both, with low frequency air coupled transducers, and higher frequency transducers, focused and unfocused, by contact and immersion. To validate the results, the ultrasonic images obtained were compared with radiographic images of the foam.

  8. Mineral Detection using K-Means Clustering Technique

    Directory of Open Access Journals (Sweden)

    P. Bangarraju

    2014-04-01

    Full Text Available This paper is all about a novel algorithm formulated with k-means clustering performed on remote sensing images. The fields of Remote Sensing are very wide and its techniques and applications are used both in the data acquisition method and data processing procedures. It is also a fast developing field with respect to all the above terms. Remote Sensing plays a very important role in understanding the natural and human processes affecting the earth’s minerals. The k-means clustering technique is used for segmentation or feature selection of passive and active imaging and non-imaging Remote Sensing, on airborne or on satellite platforms, from monochromatic to hyperspectral. So here we concentrate on the images taken on or above the surface of the earth which are applied based on the proposed algorithm to detect the minerals like Giacomo that exist on the surface of the earth. Our experimental results demonstrate that our technique can improve the computational speed of the direct k-means algorithm by an order to two orders of magnitude in the total number of distance calculations and the overall time.

  9. Rapid in situ detection of chromosome 21 by PRINS technique

    Energy Technology Data Exchange (ETDEWEB)

    Pellestor, F.; Girardet, A.; Andreo, B. [CNRS UPR 9008, Montpellier (France)] [and others

    1995-05-08

    The {open_quotes}PRimed IN Situ labeling{close_quotes} (PRINS) method is an interesting alternative to in situ hybridization for chromosomal detection. In this procedure, chromosome labeling is performed by in situ annealing of specific oligonucleotide primers, followed by primer elongation by a Taq polymerase in the presence of labeled nucleotides. Using this process, we have developed a simple and semi-automatic method for rapid in situ detection of human chromosome 21. The reaction was performed on a programmable temperature cycler, with a chromosome 21 specific oligonucleotide primer. Different samples of normal and trisomic lymphocytes and amniotic fluid cells were used for testing the method. Specific labeling of chromosome 21 was obtained in both metaphases and interphase nuclei in a 1 hour reaction. The use of oligonucleotide primer for in situ labeling overcomes the need for complex preparations of specific DNA probes. The present results demonstrate that PRINS may be a simple and reliable technique for rapidly detecting aneuploidies. 18 refs., 1 fig.

  10. Efficient watermark detection by using the longest common substring technique

    Directory of Open Access Journals (Sweden)

    Taha M. Mohamed

    2011-07-01

    Full Text Available Large scale of watermarking methods is available in the literature. These methods differ in visibility, capacity, and robustness. In watermarking, the robustness against attacks is the most challenging issue. The desynchronization attacks are the most serious problems facing the watermarking process. The traditional correlation methods fail in watermark detection. Until today there is no widely used algorithm for solving the desynchronization attacks. In this paper, we will introduce a new algorithm for solving the watermark desynchronization attacks. The watermark embedding and detection models are introduced. So, these models are related to the attacker model by presenting four attacking scenarios. We show the effect of each attack scenario on bit rate, signal distortion, and robustness. We conclude that, the attacker could not distort a big part of the watermark. So, we suggest using a probabilistic embedding model combined with the longest common substring technique. This combination is efficient in solving the desynchronization attacks. Results show that, the proposed algorithm is powerful against the attacking scenarios. Moreover, the watermark is still be detected even if only 5% of the watermark is recovered.

  11. Detection of localized damage by eddy currents technique

    Directory of Open Access Journals (Sweden)

    Aoukili A.

    2014-01-01

    Full Text Available Non destructive evaluation techniques based on eddy currents (EC are largely used for quality control of the castings in a lot of industries. The principle of detection by EC consists in using an adequate inductive coil to generate them by a variable magnetic field, and measuring their effects by using one or several sensors. These effects result from the interaction between the induced magnetic field and the excited conductive material. A local variation of the physical properties or geometry of the tested sample, due to a singularity or a flaw, causes a modification of the EC distribution, enabling thus detection. In order to optimize the capacity of defect revealing by means of EC based probes, an accurate modelling of the problem is essential. This can be used to perform simulation of the EC distribution under different circumstances and to analyze the EC sensitivity to the various implicated parameters. In this work, the modelling of EC is made by using the finite element method. Using a B-scan strategy was used, detection of a small defect having the shape of an open cavity is shown to be correctly indicated via monitoring variations of the induced voltage in the receiver coil.

  12. 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

  13. Pollution detection using the spectral fluorescent signatures (SFS technique

    Directory of Open Access Journals (Sweden)

    Mª Del Carmen Martín

    2014-06-01

    Full Text Available This work has been developed in the Applied Physics Department at the University of Vigo within the line of research based on the treatment of the degraded water by pollutants through the use of microalgae, reducing the emissions of greenhouse gases through the absorption of CO2 in the process and the reuse of biomass as biofuel. Remote sensing techniques have contributed to a great extent to the development of oil pollution monitoring systems. However, the available detection methods, mainly designed for spaceborne and airborne long distance inspection, are too expensive and complex to be used in an operational way by relatively unskilled personnel. In the framework of DEOSOM project (European AMPERA project, an innovative water monitoring method was proposed, in two steps: early oil spill detection using a portable shipborne laser-induced fluorescence LIDAR (LIF/LIDAR, and analysis of suspicious water samples in laboratory using the Spectral Fluorescent Signature (SFS technique. This work is focused on the second technique. This system aims to optimize the production of microalgae for biofuel and contaminant cleaning applications and was developed and tested in photo-bioreactors in the University of Vigo within the EnerBioAlgae project (SUDOE. In this project, the SFS technique was used as a diagnostic tool employing the fluorescence analyzer INSTANT-SCREENER M53UVC. The Spectral Fluorescence Signature technique (SFS is based on compounds fluorescence properties. The fluorescence intensity of a sample is measured at different excitation and emission wavelengths to produce a 3-dimensional fluorescence matrix, which can also be presented as a 2-dimensional color image where the color shows the intensity of the fluorescence. These matrices offer qualitative and quantitative information, since they can be useful for the identification of different substances from their characteristic excitation and emission spectra of fluorescence. They also

  14. 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.

  15. 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...

  16. 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...

  17. 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.

  18. Plagiarism Detection Using Artificial Intelligence Technique In Multiple Files

    Directory of Open Access Journals (Sweden)

    Mausumi Sahu

    2015-08-01

    Full Text Available Plagiarism relates to the act of taking information or ideas of someone else and demand it as your own. Basically it reproduce the existing information in modified format. In every field of education it becomes a serious issue. Various techniques and tools are derived these days to detect plagiarism. Various types of plagiarism are there like text matching copy paste grammar based method etc.This paper proposes a new method implemented in a program where we utilise a text set to identify the copied part by comparing with some existing multiple files. Here we put the concept of a machine learning language i.e k-NN. It helps us to identify whether a paper is plagiarized or not.

  19. Signal processing techniques for atrial fibrillation source detection.

    Science.gov (United States)

    Ambadkar, Minal; Leonelli, Fabio M; Sankar, Ravi

    2014-01-01

    In clinical practice, Atrial Fibrillation (AF) is the most common and critical cardiac arrhythmia encountered. The treatment that can ensure permanent AF removal is catheter ablation, where cardiologists destroy the affected cardiac muscle cells with RF or Laser. In this procedure it is necessary to know exactly from which part of the heart AF triggers are originated. Various signal processing algorithms provide a strong tool to track AF sources. This study proposes, signal processing techniques that can be exploited for characterization, analysis and source detection of AF signals. These algorithms are implemented on Electrocardiogram (ECG) and intracardiac signals which contain important information that allows the analysis of anatomic and physiologic aspects of the whole cardiac muscle.

  20. 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.

  1. 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.

  2. 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.

  3. 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)

  4. Digital Image Processing Technique for Breast Cancer Detection

    Science.gov (United States)

    Guzmán-Cabrera, R.; Guzmán-Sepúlveda, J. R.; Torres-Cisneros, M.; May-Arrioja, D. A.; Ruiz-Pinales, J.; Ibarra-Manzano, O. G.; Aviña-Cervantes, G.; Parada, A. González

    2013-09-01

    Breast cancer is the most common cause of death in women and the second leading cause of cancer deaths worldwide. Primary prevention in the early stages of the disease becomes complex as the causes remain almost unknown. However, some typical signatures of this disease, such as masses and microcalcifications appearing on mammograms, can be used to improve early diagnostic techniques, which is critical for women’s quality of life. X-ray mammography is the main test used for screening and early diagnosis, and its analysis and processing are the keys to improving breast cancer prognosis. As masses and benign glandular tissue typically appear with low contrast and often very blurred, several computer-aided diagnosis schemes have been developed to support radiologists and internists in their diagnosis. In this article, an approach is proposed to effectively analyze digital mammograms based on texture segmentation for the detection of early stage tumors. The proposed algorithm was tested over several images taken from the digital database for screening mammography for cancer research and diagnosis, and it was found to be absolutely suitable to distinguish masses and microcalcifications from the background tissue using morphological operators and then extract them through machine learning techniques and a clustering algorithm for intensity-based segmentation.

  5. 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.

  6. 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)

  7. 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

  8. Photogrammetric detection technique for rotor blades structural characterization

    Science.gov (United States)

    Enei, C.; Bernardini, G.; Serafini, J.; Mattioni, L.; Ficuciello, C.; Vezzari, V.

    2015-11-01

    This paper describes an innovative use of photogrammetric detection techniques to experimentally estimate structural/inertial properties of helicopter rotor blades. The identification algorithms for the evaluation of mass and flexural stiffness distributions are an extension of the ones proposed by Larsen, whereas the procedure for torsional properties determination (stiffness and shear center position) is based on the Euler-Prandtl beam theory. These algorithms rely on measurements performed through photogrammetric detection, which requires the collection of digital photos allowing the identification of 3D coordinates of labeled points (markers) on the structure through the correlation of 2D pictures. The displacements are evaluated by comparing the positions of markers in loaded and reference configuration. Being the applied loads known, the structural characteristics can be directly obtained from the measured displacements. The accuracy of the proposed identification algorithms has been firstly verified by comparison with numerical and experimental data, and then applied to the structural characterization of two main rotor blades, designed for ultra-light helicopter applications.

  9. Advanced signal processing technique for damage detection in steel tubes

    Science.gov (United States)

    Amjad, Umar; Yadav, Susheel Kumar; Dao, Cac Minh; Dao, Kiet; Kundu, Tribikram

    2016-04-01

    In recent years, ultrasonic guided waves gained attention for reliable testing and characterization of metals and composites. Guided wave modes are excited and detected by PZT (Lead Zirconate Titanate) transducers either in transmission or reflection mode. In this study guided waves are excited and detected in the transmission mode and the phase change of the propagating wave modes are recorded. In most of the other studies reported in the literature, the change in the received signal strength (amplitude) is investigated with varying degrees of damage while in this study the change in phase is correlated with the extent of damage. Feature extraction techniques are used for extracting phase and time-frequency information. The main advantage of this approach is that the bonding condition between the transducer and the specimen does not affect the phase while it can affect the strength of recorded signal. Therefore, if the specimen is not damaged but the transducer-specimen bonding is deteriorated then the received signal strength is altered but the phase remains same and thus false positive predictions for damage can be avoided.

  10. Techniques of Glaucoma Detection From Color Fundus Images: A Review

    Directory of Open Access Journals (Sweden)

    Malaya Kumar Nath

    2012-09-01

    Full Text Available Glaucoma is a generic name for a group of diseases which causes progressive optic neuropathy and vision loss due to degeneration of the optic nerves. Optic nerve cells act as transducer and convert light signal entered into the eye to electrical signal for visual processing in the brain. The main risk factors of glaucoma are elevated intraocular pressure exerted by aqueous humour, family history of glaucoma (hereditary and diabetes. It causes damages to the eye, whether intraocular pressure is high, normal or below normal. It causes the peripheral vision loss. There are different types of glaucoma. Some glaucoma occurs suddenly. So, detection of glaucoma is essential for minimizing the vision loss. Increased cup area to disc area ratio is the significant change during glaucoma. Diagnosis of glaucoma is based on measurement of intraocular pressure by tonometry, visual field examination by perimetry and measurement of cup area to disc area ratio from the color fundus images. In this paper the different signal processing techniques are discussed for detection and classification of glaucoma.

  11. 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.

  12. 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.)

  13. Superselective retrograde lymphatic duct embolization for management of postoperative lymphatic leak.

    Science.gov (United States)

    Arslan, Bülent; Masrani, Abdulrahman; Tasse, Jordan Cameron; Stenson, Kerstin; Turba, Ülkü Cenk

    2017-01-01

    Lymphatic leak is a well-documented complication following neck dissection surgeries. When conservative methods fail to control the leak, thoracic duct embolization becomes an option. Transabdominal access is the standard for this procedure; however, it is not always feasible. We discuss a technique of selective lymphatic vessel embolization utilizing retrograde transvenous access.

  14. Automatic colonic polyp detection using multi-objective evolutionary techniques

    Science.gov (United States)

    Li, Jiang; Huang, Adam; Yao, Jianhua; Bitter, Ingmar; Petrick, Nicholas; Summers, Ronald M.; Pickhardt, Perry J.; Choi, J. Richard

    2006-03-01

    Colonic polyps appear like elliptical protrusions on the inner wall of the colon. Curvature based features for colonic polyp detection have proved to be successful in several computer-aided diagnostic CT colonography (CTC) systems. Some simple thresholds are set for those features for creating initial polyp candidates, sophisticated classification scheme are then applied on these polyp candidates to reduce false positives. There are two objective functions, the number of missed polyps and false positive rate, that need to be minimized when setting those thresholds. These two objectives conflict and it is usually difficult to optimize them both by a gradient search. In this paper, we utilized a multiobjective evolutionary method, the Strength Pareto Evolutionary Algorithm (SPEA2), to optimize those thresholds. SPEA2 incorporates the concept of Pareto dominance and applies genetic techniques to evolve individual solutions to the Pareto front. The SPEA2 algorithm was applied to colon CT images from 27 patients each having a prone and a supine scan. There are 40 colonoscopically confirmed polyps resulting in 72 positive detections in CTC reading. The results obtained by SPEA2 were compared with those obtained by our old system, where an appropriate value was set for each of those thresholds by a histogram examination method. If we keep the sensitivity the same as that of our old system, the SPEA2 algorithm reduced false positive rate by 76.4% from average false positive 55.6 to 13.3 per data set. If the false positive rate is kept the same for both systems, SPEA2 increased the sensitivity by 13.1% from 53 to 61 among 72 ground truth detections.

  15. 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.

  16. 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.)

  17. Measurement uncertainty on subsurface defects detection using active infrared thermographic technique

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Yoon Jae; Kim [Kongju National University, Cheonan (Korea, Republic of); Choi, Won Jae [Center for Safety Measurements, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2015-10-15

    Active infrared thermography methods have been known to possess good fault detection capabilities for the detection of defects in materials compared to the conventional passive thermal infrared imaging techniques. However, the reliability of the technique has been under scrutiny. This paper proposes the lock-in thermography technique for the detection and estimation of artificial subsurface defect size and depth with uncertainty measurement.

  18. 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.

  19. 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.

  20. Detection of irradiated chestnuts: preliminary study using three analytical techniques

    Science.gov (United States)

    Mangiacotti, Michele; Chiaravalle, Antonio Eugenio; Marchesani, Giuliana; De Sio, Antonio; Boniglia, Concetta; Bortolin, Emanuela; Onori, Sandro

    2009-07-01

    Irradiation of chestnuts has recently been considered as an alternative treatment to fumigation to reduce the considerable amount of the product normally lost during post-harvest period. The treatment is allowed in countries such as Korea and, in view of a possible extension to European countries, to permit the legal controls as required by the directive 1999/2/EC [ European Parliament and Council Directive, 1999/2/EC, on the approximation of the laws of the Member States concerning foods and food ingredients treated with ionising radiation. Official Journal of the European Communities. L 66/16 of 13.3.1999] and meet consumer consensus, reliable methods for detecting irradiated chestnuts have to be proposed. The aim of the present work was to test the efficacy of the European Standard EN 13751, EN 1788, EN 1787 and EN 13708 in detecting irradiated chestnuts. For this purpose, six sets of "Montella" chestnuts, a typical Italian variety recognized as a PGI (protected geographical indication), non-irradiated and irradiated at different doses in the 0.1-1 kGy range, were analysed by thermoluminescence (TL), photo-stimulated luminescence (PSL) (screening and calibrated PSL) and ESR techniques. PSL and TL analysis results revealed the low luminescence sensitivity of the chestnuts. Nevertheless, PSL screening data were in the intermediate band above the negative threshold (at all doses except at the lowest one) and TL analysis led to correct positive classifications even at the lowest dose tested (0.15 Gy). On the contrary, no radio-induced ESR signal could be registered with the irradiated samples of chestnut shell or pulp.

  1. Detection of irradiated chestnuts: preliminary study using three analytical techniques

    Energy Technology Data Exchange (ETDEWEB)

    Mangiacotti, Michele [Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, Foggia (Italy)], E-mail: izsfgchimica@infinito.it; Chiaravalle, Antonio Eugenio; Marchesani, Giuliana [Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, Foggia (Italy); De Sio, Antonio [La Dolce Irpinia Srl - Montella (AV) (Italy); Boniglia, Concetta [Department of Public Veterinary Health and Food Safety, Istituto Superiore di Sanita, Rome (Italy); Bortolin, Emanuela; Onori, Sandro [Department of Technology and Health, Istituto Superiore di Sanita, Rome (Italy)

    2009-07-15

    Irradiation of chestnuts has recently been considered as an alternative treatment to fumigation to reduce the considerable amount of the product normally lost during post-harvest period. The treatment is allowed in countries such as Korea and, in view of a possible extension to European countries, to permit the legal controls as required by the directive 1999/2/EC [/2/EC, on the approximation of the laws of the Member States concerning foods and food ingredients treated with ionising radiation. Official Journal of the European Communities. L 66/16 of 13.3.1999] and meet consumer consensus, reliable methods for detecting irradiated chestnuts have to be proposed. The aim of the present work was to test the efficacy of the European Standard EN 13751, EN 1788, EN 1787 and EN 13708 in detecting irradiated chestnuts. For this purpose, six sets of 'Montella' chestnuts, a typical Italian variety recognized as a PGI (protected geographical indication), non-irradiated and irradiated at different doses in the 0.1-1 kGy range, were analysed by thermoluminescence (TL), photo-stimulated luminescence (PSL) (screening and calibrated PSL) and ESR techniques. PSL and TL analysis results revealed the low luminescence sensitivity of the chestnuts. Nevertheless, PSL screening data were in the intermediate band above the negative threshold (at all doses except at the lowest one) and TL analysis led to correct positive classifications even at the lowest dose tested (0.15 Gy). On the contrary, no radio-induced ESR signal could be registered with the irradiated samples of chestnut shell or pulp.

  2. 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...

  3. 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.

  4. Online technique for detecting state of onboard fiber optic gyroscope.

    Science.gov (United States)

    Miao, Zhiyong; Xu, Dingjie; He, Kunpeng; Pang, Shuwan; Tian, Chunmiao

    2015-02-01

    Although angle random walk (ARW) of fiber optic gyroscope (FOG) has been well modeled and identified before being integrated into the high-accuracy attitude control system of satellite, aging and unexpected failures can affect the performance of FOG after launch, resulting in the variation of ARW coefficient. Therefore, the ARW coefficient can be regarded as an indicator of "state of health" for FOG diagnosis in some sense. The Allan variance method can be used to estimate ARW coefficient of FOG, however, it requires a large amount of data to be stored. Moreover, the procedure of drawing slope lines for estimation is painful. To overcome the barriers, a weighted state-space model that directly models the ARW to obtain a nonlinear state-space model was established for FOG. Then, a neural extended-Kalman filter algorithm was implemented to estimate and track the variation of ARW in real time. The results of experiment show that the proposed approach is valid to detect the state of FOG. Moreover, the proposed technique effectively avoids the storage of data.

  5. Damage detection technique by measuring laser-based mechanical impedance

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeonseok; Sohn, Hoon [Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (Daehak-ro 291, Yuseong-gu, Daejeon 305-701) (Korea, Republic of)

    2014-02-18

    This study proposes a method for measurement of mechanical impedance using noncontact laser ultrasound. The measurement of mechanical impedance has been of great interest in nondestructive testing (NDT) or structural health monitoring (SHM) since mechanical impedance is sensitive even to small-sized structural defects. Conventional impedance measurements, however, have been based on electromechanical impedance (EMI) using contact-type piezoelectric transducers, which show deteriorated performances induced by the effects of a) Curie temperature limitations, b) electromagnetic interference (EMI), c) bonding layers and etc. This study aims to tackle the limitations of conventional EMI measurement by utilizing laser-based mechanical impedance (LMI) measurement. The LMI response, which is equivalent to a steady-state ultrasound response, is generated by shooting the pulse laser beam to the target structure, and is acquired by measuring the out-of-plane velocity using a laser vibrometer. The formation of the LMI response is observed through the thermo-mechanical finite element analysis. The feasibility of applying the LMI technique for damage detection is experimentally verified using a pipe specimen under high temperature environment.

  6. Online technique for detecting state of onboard fiber optic gyroscope

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Zhiyong; He, Kunpeng, E-mail: pengkhe@126.com; Pang, Shuwan [Department of Automation, Harbin Engineering University, Harbin, Heilongjiang 150000 (China); Xu, Dingjie [School of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin, Heilongjiang 150000 (China); Tian, Chunmiao [Department of Information and Communication Engineering, Harbin Engineering University, Harbin, Heilongjiang 150000 (China)

    2015-02-15

    Although angle random walk (ARW) of fiber optic gyroscope (FOG) has been well modeled and identified before being integrated into the high-accuracy attitude control system of satellite, aging and unexpected failures can affect the performance of FOG after launch, resulting in the variation of ARW coefficient. Therefore, the ARW coefficient can be regarded as an indicator of “state of health” for FOG diagnosis in some sense. The Allan variance method can be used to estimate ARW coefficient of FOG, however, it requires a large amount of data to be stored. Moreover, the procedure of drawing slope lines for estimation is painful. To overcome the barriers, a weighted state-space model that directly models the ARW to obtain a nonlinear state-space model was established for FOG. Then, a neural extended-Kalman filter algorithm was implemented to estimate and track the variation of ARW in real time. The results of experiment show that the proposed approach is valid to detect the state of FOG. Moreover, the proposed technique effectively avoids the storage of data.

  7. Modeling and comparative study of various detection techniques for FMCW LIDAR using optisystem

    Science.gov (United States)

    Elghandour, Ahmed H.; Ren, Chen D.

    2013-09-01

    In this paper we investigated the different detection techniques especially direct detection, coherent heterodyne detection and coherent homodyne detection on FMCW LIDAR system using Optisystem package. A model for target, propagation channel and various detection techniques were developed using Optisystem package and then a comparative study among various detection techniques for FMCW LIDAR systems is done analytically and simulated using the developed model. Performance of direct detection, heterodyne detection and homodyne detection for FMCW LIDAR system was calculated and simulated using Optisystem package. The output simulated performance was checked using simulated results of MATLAB simulator. The results shows that direct detection is sensitive to the intensity of the received electromagnetic signal and has low complexity system advantage over the others detection architectures at the expense of the thermal noise is the dominant noise source and the sensitivity is relatively poor. In addition to much higher detection sensitivity can be achieved using coherent optical mixing which is performed by heterodyne and homodyne detection.

  8. 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.

  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. Hyperspectral remote sensing techniques for early detection of plant diseases

    Science.gov (United States)

    Krezhova, Dora; Maneva, Svetla; Zdravev, Tomas

    Hyperspectral remote sensing is an emerging, multidisciplinary field with diverse applications in Earth observation. Nowadays spectral remote sensing techniques allow presymptomatic monitoring of changes in the physiological state of plants with high spectral resolution. Hyperspectral leaf reflectance and chlorophyll fluorescence proved to be highly suitable for identification of growth anomalies of cultural plants that result from the environmental changes and different stress factors. Hyperspectral technologies can find place in many scientific areas, as well as for monitoring of plants status and functioning to help in making timely management decisions. This research aimed to detect a presence of viral infection in young pepper plants (Capsicum annuum L.) caused by Cucumber Mosaic Virus (CMV) by using hyperspectral reflectance and fluorescence data and to assess the effect of some growth regulators on the development of the disease. In Bulgaria CMV is one of the widest spread pathogens, causing the biggest economical losses in crop vegetable production. Leaf spectral reflectance and fluorescence data were collected by a portable fibre-optics spectrometer in the spectral ranges 450÷850 nm and 600-900 nm. Greenhouse experiment with pepper plants of two cultivars, Sivria (sensitive to CMV) and Ostrion (resistant to CMV) were used. The plants were divided into six groups. The first group consisted of healthy (control) plants. At growth stage 4-6 expanded leaf, the second group was inoculated with CMV. The other four groups were treated with growth regulators: Spermine, MEIA (beta-monomethyl ester of itaconic acid), ВТН (benzo(1,2,3)thiadiazole-7-carbothioic acid-S-methyl ester) and Phytoxin. On the next day, the pepper plants of these four groups were inoculated with CMV. The viral concentrations in the plants were determined by the serological method DAS-ELISA. Statistical, first derivative and cluster analysis were applied and several vegetation indices were

  13. Region Duplication Forgery Detection Technique Based on SURF and HAC

    Directory of Open Access Journals (Sweden)

    Parul Mishra

    2013-01-01

    Full Text Available Region duplication forgery detection is a special type of forgery detection approach and widely used research topic under digital image forensics. In copy move forgery, a specific area is copied and then pasted into any other region of the image. Due to the availability of sophisticated image processing tools, it becomes very hard to detect forgery with naked eyes. From the forged region of an image no visual clues are often detected. For making the tampering more robust, various transformations like scaling, rotation, illumination changes, JPEG compression, noise addition, gamma correction, and blurring are applied. So there is a need for a method which performs efficiently in the presence of all such attacks. This paper presents a detection method based on speeded up robust features (SURF and hierarchical agglomerative clustering (HAC. SURF detects the keypoints and their corresponding features. From these sets of keypoints, grouping is performed on the matched keypoints by HAC that shows copied and pasted regions.

  14. Exploring underwater target detection by imaging polarimetry and correlation techniques.

    Science.gov (United States)

    Dubreuil, M; Delrot, P; Leonard, I; Alfalou, A; Brosseau, C; Dogariu, A

    2013-02-10

    Underwater target detection is investigated by combining active polarization imaging and optical correlation-based approaches. Experiments were conducted in a glass tank filled with tap water with diluted milk or seawater and containing targets of arbitrary polarimetric responses. We found that target estimation obtained by imaging with two orthogonal polarization states always improves detection performances when correlation is used as detection criterion. This experimental study illustrates the potential of polarization imaging for underwater target detection and opens interesting perspectives for the development of underwater imaging systems.

  15. 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.

  16. A new detection technique of gas concentration with optical spectrum absorption at near-IR wavelength

    Institute of Scientific and Technical Information of China (English)

    井文才; 周之砚; 宋霄; 吴頔; 贾大功; 张红霞; 张以谟

    2009-01-01

    Wavelength modulation technique(WMT) and active intracavity technique(ACIT) are first introduced in this paper,which are used to realize the concentration detection of methane and acetylene respectively.When ACIT is combined with wavelength sweep technique(WST),the detection sensitivity of acetylene can be enhanced sharply.When ACIT is combined with WST and WMT,the detection sensitivity of acetylene can be enhanced further.

  17. Cell-Detection Technique for Automated Patch Clamping

    Science.gov (United States)

    McDowell, Mark; Gray, Elizabeth

    2008-01-01

    A unique and customizable machinevision and image-data-processing technique has been developed for use in automated identification of cells that are optimal for patch clamping. [Patch clamping (in which patch electrodes are pressed against cell membranes) is an electrophysiological technique widely applied for the study of ion channels, and of membrane proteins that regulate the flow of ions across the membranes. Patch clamping is used in many biological research fields such as neurobiology, pharmacology, and molecular biology.] While there exist several hardware techniques for automated patch clamping of cells, very few of those techniques incorporate machine vision for locating cells that are ideal subjects for patch clamping. In contrast, the present technique is embodied in a machine-vision algorithm that, in practical application, enables the user to identify good and bad cells for patch clamping in an image captured by a charge-coupled-device (CCD) camera attached to a microscope, within a processing time of one second. Hence, the present technique can save time, thereby increasing efficiency and reducing cost. The present technique involves the utilization of cell-feature metrics to accurately make decisions on the degree to which individual cells are "good" or "bad" candidates for patch clamping. These metrics include position coordinates (x,y) in the image plane, major-axis length, minor-axis length, area, elongation, roundness, smoothness, angle of orientation, and degree of inclusion in the field of view. The present technique does not require any special hardware beyond commercially available, off-the-shelf patch-clamping hardware: A standard patchclamping microscope system with an attached CCD camera, a personal computer with an imagedata- processing board, and some experience in utilizing imagedata- processing software are all that are needed. A cell image is first captured by the microscope CCD camera and image-data-processing board, then the image

  18. Portable Microleak-Detection System

    Science.gov (United States)

    Rivers, H. Kevin; Sikora, Joseph G.; Sankaran, Sankara N.

    2007-01-01

    The figure schematically depicts a portable microleak-detection system that has been built especially for use in testing hydrogen tanks made of polymer-matrix composite materials. (As used here, microleak signifies a leak that is too small to be detectable by the simple soap-bubble technique.) The system can also be used to test for microleaks in tanks that are made of other materials and that contain gases other than hydrogen. Results of calibration tests have shown that measurement errors are less than 10 percent for leak rates ranging from 0.3 to 200 cm3/min. Like some other microleak-detection systems, this system includes a vacuum pump and associated plumbing for sampling the leaking gas, and a mass spectrometer for analyzing the molecular constituents of the gas. The system includes a flexible vacuum chamber that can be attached to the outer surface of a tank or other object of interest that is to be tested for leakage (hereafter denoted, simply, the test object). The gas used in a test can be the gas or vapor (e.g., hydrogen in the original application) to be contained by the test object. Alternatively, following common practice in leak testing, helium can be used as a test gas. In either case, the mass spectrometer can be used to verify that the gas measured by the system is the test gas rather than a different gas and, hence, that the leak is indeed from the test object.

  19. 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.

  20. 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.

  1. Anti-Phishing Technique to Detect URL Obfuscation Jigar

    Directory of Open Access Journals (Sweden)

    Rathod,

    2014-05-01

    Full Text Available Phishing is a criminal scheme to steal the user‟s personal data and other credential information. It is a fraud that acquires victim‟s confidential information such as password, bank account detail, credit card number, financial username and password etc. and later it can be misuse by attacker. In this research paper, we proposed a new anti-phishing algorithm, which we call ObURL Detection Algorithm. The ObURL Detection Algorithm used to detect the URL Obfuscation Phishing attacks and it provides the multilayer security over the internet fraud. The ObURL Detection Algorithm can detect the hyperlink, content of hyperlink‟s destination URL, iFrame in email, input form, input form in iFrame source URL, iFrame within iFrame, and after all that multiple tests will be perform such as DNS Test, IP address Test, URL Encode Test, Shorten URL Test, Black and Whitelist Test, URL pattern matching Test On that collected data. Our experiments verified that ObURL Detection Algorithm is effective to detect both known and unknown URL Obfuscation phishing attacks.

  2. Detection of buried landmine with X-ray backscatter technique

    Energy Technology Data Exchange (ETDEWEB)

    Yuk, Sunwoo [Department of Electronics and Information Engineering, Korea University, Seoul (Korea, Republic of)]. E-mail: sunwoo@korea.ac.kr; Kim, Kwang Hyun [Chosun University, 375, Seosuk-Dong, Dong-Gu, Gwangju (Korea, Republic of); Yi, Yun [Department of Electronics and Information Engineering, Korea University, Seoul (Korea, Republic of)

    2006-11-30

    We describe a continuously operating scanning X-ray imaging system developed for landmine detection based on a backscatter X-ray principle, thus detection is done from the same side as the source. The source operates at 120 kV p and 3 mA. To study the physics of Compton X-ray backscattering, the photon transport factor, backscatter factor (BSF) and backscatter probability (BSP) were simulated using Monte-Carlo calculations using the generalized particle transport program MCNP. Based on the Monte-Carlo analyses results, a mine detecting system has been designed. It potentially has a low false alarm rate and a high detection probability, and a direct imaging facility.

  3. Early Detection of Breast Cancer using SVM Classifier Technique

    CERN Document Server

    Rejani, Y Ireaneus Anna

    2009-01-01

    This paper presents a tumor detection algorithm from mammogram. The proposed system focuses on the solution of two problems. One is how to detect tumors as suspicious regions with a very weak contrast to their background and another is how to extract features which categorize tumors. The tumor detection method follows the scheme of (a) mammogram enhancement. (b) The segmentation of the tumor area. (c) The extraction of features from the segmented tumor area. (d) The use of SVM classifier. The enhancement can be defined as conversion of the image quality to a better and more understandable level. The mammogram enhancement procedure includes filtering, top hat operation, DWT. Then the contrast stretching is used to increase the contrast of the image. The segmentation of mammogram images has been playing an important role to improve the detection and diagnosis of breast cancer. The most common segmentation method used is thresholding. The features are extracted from the segmented breast area. Next stage include,...

  4. Quantitative Emboli Detection Using Nonlinear Ultrasound Technique Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a new and innovative method for the detection and classification of emboli flowing into the brain through Carotid arteries, specifically for...

  5. THE IMPROVEMENT OF RT-PCR TECHNIQUE ON DETECTING ROTAVIRUS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective To establish a speed and effective method to detect rotavirus. Methods Using ELISA and one step RT-PCR to detect 196 clinic samples from Xi'an area. Results Compared with ELISA method, one step RT PCR was more sensitive and specific (P <0.05). Conclusion One step RT-PCR is a simple, speed, sensitive and spe cific method for clinic and epidemic studies of rotavirus.

  6. Leakage detection in galvanized iron pipelines using ensemble empirical mode decomposition analysis

    Science.gov (United States)

    Amin, Makeen; Ghazali, M. Fairusham

    2015-05-01

    There are many numbers of possible approaches to detect leaks. Some leaks are simply noticeable when the liquids or water appears on the surface. However many leaks do not find their way to the surface and the existence has to be check by analysis of fluid flow in the pipeline. The first step is to determine the approximate position of leak. This can be done by isolate the sections of the mains in turn and noting which section causes a drop in the flow. Next approach is by using sensor to locate leaks. This approach are involves strain gauge pressure transducers and piezoelectric sensor. the occurrence of leaks and know its exact location in the pipeline by using specific method which are Acoustic leak detection method and transient method. The objective is to utilize the signal processing technique in order to analyse leaking in the pipeline. With this, an EEMD method will be applied as the analysis method to collect and analyse the data.

  7. Developement of leakage localization technique by using acoustic signal

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y. H.; Jeon, J. H.; Seo, D. H.; Kim, K. W. [KAIST, Daejeon (Korea, Republic of)

    2010-07-15

    The objective of this research is to develop a leakage monitoring system for pipelines or valves in the secondary water system of a nuclear power plant. The system aims to detect the existence of leakage and to estimate the leak location, especially by utilizing the noise generated from the leak. It is safe, precise real-time alert system compared with the previous monitoring methods and tools such as the visual test and the thermal imaging camera. When there exists leakage in the pipeline or valves of nuclear power plant, the noise due to gas flow is radiated through leak region. That is, the secondary water system with leakage generates different noise from the system without leakage. This motivates us to measure and analyze the noise generated from the secondary water system, so as firstly to detect the existence of leakage, and secondly to estimate the leak location by using the noise source identification technique such as beamforming and acoustic holography. Especially the beamforming method models the signal from the noise source to estimate the location of source. Therefore, it is necessary to model the noise due to leakage which is dependent upon parameters. In the process of leak localization, the reflected wave due to interior walls and the measurement noise should be removed for the precise estimation. Therefore, we attempt to characterize the reflected wave and the measurement noise by modeling the interior sound field, thus to remove them and to localize the leak location with high precision

  8. A contrast stretching bilateral closing top-hat Otsu threshold technique for crack detection in images.

    Science.gov (United States)

    Sim, K S; Kho, Y Y; Tso, C P; Nia, M E; Ting, H Y

    2013-01-01

    Detection of cracks from stainless steel pipe images is done using contrast stretching technique. The technique is based on an image filter technique through mathematical morphology that can expose the cracks. The cracks are highlighted and noise removal is done efficiently while still retaining the edges. An automated crack detection system with a camera platform has been successfully implemented. We compare crack extraction in terms of quality measures with those of Otsu's threshold technique and the another technique (Iyer and Sinha, 2005). The algorithm shown is able to achieve good results and perform better than these other techniques.

  9. BENCHMARKING MACHINE LEARNING TECHNIQUES FOR SOFTWARE DEFECT DETECTION

    Directory of Open Access Journals (Sweden)

    Saiqa Aleem

    2015-06-01

    Full Text Available Machine Learning approaches are good in solving problems that have less information. In most cases, the software domain problems characterize as a process of learning that depend on the various circumstances and changes accordingly. A predictive model is constructed by using machine learning approaches and classified them into defective and non-defective modules. Machine learning techniques help developers to retrieve useful information after the classification and enable them to analyse data from different perspectives. Machine learning techniques are proven to be useful in terms of software bug prediction. This study used public available data sets of software modules and provides comparative performance analysis of different machine learning techniques for software bug prediction. Results showed most of the machine learning methods performed well on software bug datasets.

  10. A Cosmic Watershed: the WVF Void Detection Technique

    CERN Document Server

    Platen, Erwin; Jones, Bernard J T

    2007-01-01

    On megaparsec scales the Universe is permeated by an intricate filigree of clusters, filaments, sheets and voids, the Cosmic Web. For the understanding of its dynamical and hierarchical history it is crucial to identify objectively its complex morphological components. One of the most characteristic aspects is that of the dominant underdense Voids, the product of a hierarchical process driven by the collapse of minor voids in addition to the merging of large ones. In this study we present an objective void finder technique which involves a minimum of assumptions about the scale, structure and shape of voids. Our void finding method, the Watershed Void Finder (WVF), is based upon the Watershed Transform, a well-known technique for the segmentation of images. Importantly, the technique has the potential to trace the existing manifestations of a void hierarchy. The basic watershed transform is augmented by a variety of correction procedures to remove spurious structure resulting from sampling noise. This study c...

  11. A Hybrid Islanding Detection Technique Using Average Rate of Voltage Change and Real Power Shift

    DEFF Research Database (Denmark)

    Mahat, Pukar; Chen, Zhe; Bak-Jensen, Birgitte

    2009-01-01

    technique is proposed to solve this problem. An average rate of voltage change (passive technique) has been used to initiate a real power shift (active technique), which changes the eal power of distributed generation (DG), when the passive technique cannot have a clear discrimination between islanding......The mainly used islanding detection techniques may be classified as active and passive techniques. Passive techniques don't perturb the system but they have larger nondetection znes, whereas active techniques have smaller nondetection zones but they perturb the system. In this paper, a new hybrid...

  12. A novel hand-type detection technique with fingerprint sensor

    Science.gov (United States)

    Abe, Narishige; Shinzaki, Takashi

    2013-05-01

    In large-scale biometric authentication systems such as the US-Visit (USA), a 10-fingerprints scanner which simultaneously captures four fingerprints is used. In traditional systems, specific hand-types (left or right) are indicated, but it is difficult to detect hand-type due to the hand rotation and the opening and closing of fingers. In this paper, we evaluated features that were extracted from hand images (which were captured by a general optical scanner) that are considered to be effective for detecting hand-type. Furthermore, we extended the knowledge to real fingerprint images, and evaluated the accuracy with which it detects hand-type. We obtained an accuracy of about 80% with only three fingers (index, middle, ring finger).

  13. Defect Detection Techniques for Airbag Production Sewing Stages

    Directory of Open Access Journals (Sweden)

    Raluca Brad

    2014-01-01

    Full Text Available Airbags are subjected to strict quality control in order to ensure passengers safety. The quality of fabric and sewing thread influences the final product and therefore, sewing defects must be early and accurately detected, in order to remove the item from production. Airbag seams assembly can take various forms, using linear and circle primitives, with threads of different colors and length densities, creating lockstitch or double threads chainstitch. The paper presents a framework for the automatic detection of defects occurring during the airbag sewing stage. Types of defects as skipped stitch, missed stitch, or superimposed seam for lockstitch and two threads chainstitch are detected and marked. Using image processing methods, the proposed framework follows the seams path and determines if a color pattern of the considered stitches is valid.

  14. Chemical weapons detection by fast neutron activation analysis techniques

    Science.gov (United States)

    Bach, P.; Ma, J. L.; Froment, D.; Jaureguy, J. C.

    1993-06-01

    A neutron diagnostic experimental apparatus has been tested for nondestructive verification of sealed munitions. Designed to potentially satisfy a significant number of van-mobile requirements, this equipment is based on an easy to use industrial sealed tube neutron generator that interrogates the munitions of interest with 14 MeV neutrons. Gamma ray spectra are detected with a high purity germanium detector, especially shielded from neutrons and gamma ray background. A mobile shell holder has been used. Possible configurations allow the detection, in continuous or in pulsed modes, of gamma rays from neutron inelastic scattering, from thermal neutron capture, and from fast or thermal neutron activation. Tests on full scale sealed munitions with chemical simulants show that those with chlorine (old generation materials) are detectable in a few minutes, and those including phosphorus (new generation materials) in nearly the same time.

  15. A measurement-based technique for incipient anomaly detection

    KAUST Repository

    Harrou, Fouzi

    2016-06-13

    Fault detection is essential for safe operation of various engineering systems. Principal component analysis (PCA) has been widely used in monitoring highly correlated process variables. Conventional PCA-based methods, nevertheless, often fail to detect small or incipient faults. In this paper, we develop new PCA-based monitoring charts, combining PCA with multivariate memory control charts, such as the multivariate cumulative sum (MCUSUM) and multivariate exponentially weighted moving average (MEWMA) monitoring schemes. The multivariate control charts with memory are sensitive to small and moderate faults in the process mean, which significantly improves the performance of PCA methods and widen their applicability in practice. Using simulated data, we demonstrate that the proposed PCA-based MEWMA and MCUSUM control charts are more effective in detecting small shifts in the mean of the multivariate process variables, and outperform the conventional PCA-based monitoring charts. © 2015 IEEE.

  16. Early breast cancer detection using techniques other than mammography

    Energy Technology Data Exchange (ETDEWEB)

    Kopans, D.B.

    1984-09-01

    X-ray mammography is the only imaging method currently available with any proven efficacy for screening to detect early-stage, clinically occult breast cancer. Sonography has a limited role in the differentiation of cystic from solid masses and as a guide for aspiration and preoperative localization of selected breast lesions. Computed tomography has a more limited role to determine the spatial orientation of a lesion detected only in the lateral mammographic position. All other imaging methods should be considered experimental at this time.

  17. An Introduction to Dark Matter Direct Detection Searches & Techniques

    CERN Document Server

    Saab, Tarek

    2012-01-01

    Weakly Interacting Massive Particles (WIMPs), are a leading candidate for the dark matter that is observed to constitute ~25% of the total mass-energy density of the Universe. The direct detection of relic WIMPs (those produced during the early moments of the Universe's expansion) is at the forefront of active research areas in particle astrophysics with a numerous international experimental collaborations pursuing this goal. This paper presents an overview of the theoretical and practical considerations common to the design and operation of direct detection experiments, as well as their unique features and capabilities.

  18. Detection, Deterrence, Docility: Techniques of Control by Surveillance Cameras

    NARCIS (Netherlands)

    Balamir, S.

    2013-01-01

    In spite of the growing omnipresence of surveillance cameras, not much is known by the general public about their background. While many disciplines have scrutinised the techniques and effects of surveillance, the object itself remains somewhat of a mystery. A design typology of surveillance cameras

  19. 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.

  20. Direct detection of expanded trinucleotide repeats using DNA hybridization techniques

    Energy Technology Data Exchange (ETDEWEB)

    Petronis, A.; Tatuch, Y.; Kennedy, J.L. [Univ. of Toronto (Canada)] [and others

    1994-09-01

    Recently, unstable trinucleotide repeats have been shown to be the etiologic factor in several neuropsychiatric diseases, and they may play a similar role in other disorders. To our knowledge, a method that detects expanded trinucleotide sequences with the opportunity for direct localization and cloning has not been achieved. We have developed a set of hybridization-based methods for direct detection of unstable DNA expansion. Our analysis of myotonic dystrophy patients that possess different degrees of (CTG){sub n} expansion, versus unaffected controls, has demonstrated the identification of the trinucleotide instability site without any prior information regarding genetic map location. High stringency modified Southern blot hybridization with a PCR-generated trinucleotide repeat probe allowed us to detect the DNA fragment containing the expansion in myotonic dystrophy patients. The same probe was used for fluorescent in situ hybridization and several regions of (CTG){sub n}/(CAG){sub n} repeats in the human genome were detected, including the myotonic dystrophy locus on chromosome 19q. These strategies can be applied to directly clone genes involved in disorders caused by unstable DNA.

  1. Signal Detection Framework Using Semantic Text Mining Techniques

    Science.gov (United States)

    Sudarsan, Sithu D.

    2009-01-01

    Signal detection is a challenging task for regulatory and intelligence agencies. Subject matter experts in those agencies analyze documents, generally containing narrative text in a time bound manner for signals by identification, evaluation and confirmation, leading to follow-up action e.g., recalling a defective product or public advisory for…

  2. Hyperellipsoidal SVM-Based Outlier Detection Technique for Geosensor Networks

    NARCIS (Netherlands)

    Zhang, Yang; Meratnia, N.; Havinga, P.J.M.

    2009-01-01

    Recently, wireless sensor networks providing fine-grained spatio-temporal observations have become one of the major monitoring platforms for geo-applications. Along side data acquisition, outlier detection is essential in geosensor networks to ensure data quality, secure monitoring and re- liable de

  3. A Study of Rootkit Stealth Techniques and Associated Detection Methods

    Science.gov (United States)

    2007-03-01

    3.12. Detection Classification 3 . . . . . . . . . . . . . . . . . . . . . 43 3.13. Trampoline Function with Modification . . . . . . . . . . . . . 46...rooted (source function) is overwritten with a jump to the rootkit code (the detour), next the rootkit code (the trampoline ) is executed. Part of the...that it desires. The rootkit will then return the scrubbed data to the original calling function. Source Function Detour Function Trampoline Function

  4. Infrared techniques for detecting carbonization at onset of device failure

    Science.gov (United States)

    Farr, Norman; Sinofsky, Edward L.

    1997-05-01

    We describe the design, and development of an infrared detection system which detects the onset of carbonization of fluoropolymers in the presence of up to 60 watts of 1.06 micrometer laser energy. This system is used to shut down a therapeutic laser system before significant damage is done to a laser delivery device and patient. Black body radiation emitting from the diffusion tip is transmitted, backwards, through the same optical fiber as the therapeutic wavelength. Using a high power 1.06 micrometer laser mirror at 45 degrees, most of the 1.06 micrometer light is reflected while the black body radiation is passed to a holographic notch filter which further filters the signal. Still more filtering was needed before the 1.1 to 2 micrometer signal could be detected within the presence the therapeutic light using an extended indium gallium arsenide photodetector. There was still a significant detected offset which increased with laser power which necessitated a means to automatically null the offset for different laser power settings. The system is designed to be used with any unmodified laser system. It interfaces directly to or in series with most common external safety interlocks and can be used with various diffusing tips, probes or bare fibers.

  5. Robustness of movement detection techniques from motor execution

    DEFF Research Database (Denmark)

    Aliakbaryhosseinabadi, Susan; Jiang, Ning; Petrini, Laura;

    2015-01-01

    Alterations in attention are known to modify excitability of underlying cortical structures and thus the activity recorded during non-invasive electroencephalography (EEG). Brain-Computer-Interface systems for neuromodulation are based on reliable detection of intended movements from continuous EEG...

  6. Study of lip-reading detecting and locating technique

    Science.gov (United States)

    Wang, Lirong; Li, Jie; Zhao, Yanyan

    2008-03-01

    With the development of human computer interaction, lip reading technology has become a topic focus in the multimode technologic field. However, detecting and locating lip accurately are very difficult because lip contours of different people, varied illuminant conditions, head movements and other factors. Based on the methods of detecting and locating lip we proposed the methods which are based on the lips color extracted lip contour using the adaptive chromatic filter from the facial images. It is not sensitive to illumination, but appropriate chromatic lip filter is given by analyzing the entire face color and clustering statistics of lip color. It is proposed the combinable method which is preprocessing the face image including rotating the angle of face and improving image contrast in this paper and the lip region is analyzed clustering characteristics for the skin color and lip color, obtained adaptive chromatic filter which can prominent lips from the facial image. This method overcomes the varied illuminate, incline face. The experiments showed that it enhanced detection and location accurately through rough detecting lip region. It lay a good foundation for extraction the lip feature and tracking lip subsequently.

  7. Signal Detection Framework Using Semantic Text Mining Techniques

    Science.gov (United States)

    Sudarsan, Sithu D.

    2009-01-01

    Signal detection is a challenging task for regulatory and intelligence agencies. Subject matter experts in those agencies analyze documents, generally containing narrative text in a time bound manner for signals by identification, evaluation and confirmation, leading to follow-up action e.g., recalling a defective product or public advisory for…

  8. Fístulas de anastomose superior pós-gastroplastia redutora pela técnica de Higa para tratamento da obesidade mórbida: aspectos por imagem Anastomotic leaks after Roux-en-Y gastric bypass surgery by Higa's technique for treatment of morbid obesity: radiological findings

    Directory of Open Access Journals (Sweden)

    Ester Moraes Labrunie

    2008-04-01

    Full Text Available OBJETIVO: Descrever os principais aspectos radiológicos encontrados nas fístulas pós-operatórias de anastomose superior em pacientes submetidos a derivação gastrintestinal em Y de Roux pela técnica de Higa. MATERIAIS E MÉTODOS: Foram estudados 24 pacientes com fístula de anastomose no pós-operatório de gastroplastia redutora, avaliados por tomografias computadorizadas e/ou seriografias esofagogastrojejunais. RESULTADOS: As fístulas de anastomose superior ocorreram até o 30º dia de pós-operatório. Dezenove pacientes realizaram exame radiológico no momento do diagnóstico, sendo observado extravasamento de contraste, considerado sinal direto de fístula de anastomose, em dez pacientes. Dos nove restantes, em sete foi evidenciado extravasamento em exames subseqüentes, sendo ainda identificados sinais indiretos de fístula em seis destes. Sinais indiretos foram observados também em pacientes com extravasamento de contraste nos exames iniciais, sendo o pneumoperitônio o aspecto mais freqüente. Dos cinco pacientes sem exame radiológico no momento do diagnóstico, exames subseqüentes evidenciaram extravasamento de contraste em um e sinais indiretos em quatro pacientes. CONCLUSÃO: O achado radiológico mais comum foi o extravasamento de contraste (sinal direto de fístula. Os sinais indiretos foram: nível líquido bizarro, coleção intracavitária, pneumoperitônio desproporcional ao tempo pós-operatório, líquido na cavidade peritoneal, edema da anastomose inferior e distensão de delgado.OBJECTIVE: The present study was aimed at describing main radiological findings in patients who developed leaks as a complication of Roux-en-Y gastric bypass surgery by the Higa's technique. MATERIALS AND METHODS: Twenty-four patients with post-gastric bypass anastomotic leaks were evaluated by means of computed tomography or gastrointestinal series. RESULTS: Leaks of superior anastomoses generally occurred within 30 postoperative days

  9. 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....

  10. Neuro-evolutionary event detection technique for downhole microseismic surveys

    Science.gov (United States)

    Maity, Debotyam; Salehi, Iraj

    2016-01-01

    Recent years have seen a significant increase in borehole microseismic data acquisition programs associated with unconventional reservoir developments such as hydraulic fracturing programs for shale oil and gas. The data so acquired is used for hydraulic fracture monitoring and diagnostics and therefore, the quality of the data in terms of resolution and accuracy has a significant impact on its value to the industry. Borehole microseismic data acquired in such environments typically suffer from propagation effects due to the presence of thin interbedded shale layers as well as noise and interference effects. Moreover, acquisition geometry has significant impact on detectability across portions of the sensor array. Our work focuses on developing robust first arrival detection and pick selection workflow for both P and S waves specifically designed for such environments. We introduce a novel workflow for refinement of picks with immunity towards significant noise artifacts and applicability over data with very low signal-to-noise ratio provided some accurate picks have already been made. This workflow utilizes multi-step hybrid detection and classification routine which makes use of a neural network based autopicker for initial picking and an evolutionary algorithm for pick refinement. We highlight the results from an actual field case study including multiple examples demonstrating immunity towards noise and compare the effectiveness of the workflow with two contemporary autopicking routines without the application of the shared detection/refinement procedure. Finally, we use a windowed waveform cross-correlation based uncertainty estimation method for potential quality control purposes. While the workflow was developed to work with the neural network based autopicker, it can be used with any other traditional autopicker and provides significant improvements in pick detection across seismic gathers.

  11. Detection of protein microarrays by oblique-incidence reflectivity difference technique

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Biological microarrays with different proteins and different protein concentrations are detected without external labeling by an oblique-incidence reflectivity difference (OIRD) technique. The initial experiment results reveal that the intensities of OIRD signals can distinguish the different proteins and concentrations of protein. The OIRD technique promises feasible applications to life sciences for label-free and high-throughput detection.

  12. Comparison of techniques for the detection of monocyte specific antigens.

    Science.gov (United States)

    Jager, M J; Thompson, J S; Claas, F H; Van Rood, J J

    1985-10-10

    Monocyte specific antigens are relevant in renal and bone marrow transplantation, but a reproducible monocyte-antigen system has not yet been recognized. In order to establish a sensitive test system with reproducible results in monocyte serology, 3 different monocyte cytotoxicity techniques were compared. In our hands the two-colour fluorescence test on post-Ficoll total leukocyte suspensions fulfilled the criteria. This technique was used to screen sera from multiparous women and renal transplant recipients for the presence of monocyte specific antibodies. By testing sera on cells from individuals who were HLA compatible with the serum donors, anti-HLA reactions were excluded. Several promising sera containing monocyte specific antibodies were identified, thus indicating the success of our approach.

  13. A Survey on Image Segmentation Techniques Used In Leukemia Detection

    Directory of Open Access Journals (Sweden)

    Mashiat Fatma

    2014-04-01

    Full Text Available Image segmentation commonly known as partitioning of an image is one of the intrinsic parts of any image processing technique. In this image processing step, the digital image of choice is segregated into sets of pixels on the basis of some predefined and preselected measures or standards. There have been presented many algorithms for segmenting a digital image. This paper presents a general review of algorithms that have been presented for the purpose of image segmentation.

  14. DETECTING DEFECTS IN AIRCRAFT MATERIALS BY NUCLEAR TECHNIQUE (PAS)

    OpenAIRE

    EMAD A. BADAWI

    2005-01-01

    Positron annihilation spectroscopy (PAS) is one of the nuclear techniques used in material science. The present measurements are used to study the behavior of defect concentration in one of the most important materials aluminum alloys which is the 7075 alloy. It has been shown that positrons can become trapped at imperfect locations in solids and their mean lifetime can be influenced by changes in the concentration of such defects. No changes have been observed in the mean lifetime values aft...

  15. Bladder Cancer Detection Using Electrical Impedance Technique (Tabriz Mark 1

    Directory of Open Access Journals (Sweden)

    Ahmad Keshtkar

    2012-01-01

    Full Text Available Bladder cancer is the fourth most common malignant neoplasm in men and the eighth in women. Bladder pathology is usually investigated visually by cystoscopy. In this technique, biopsies are obtained from the suspected area and then, after needed procedure, the diagnostic information can be taken. This is a relatively difficult procedure and is associated with discomfort for the patient and morbidity. Therefore, the electrical impedance spectroscopy (EIS, a minimally invasive screening technique, can be used to separate malignant areas from nonmalignant areas in the urinary bladder. The feasibility of adapting this technique to screen for bladder cancer and abnormalities during cystoscopy has been explored and compared with histopathological evaluation of urinary bladder lesions. Ex vivo studies were carried out in this study by using a total of 30 measured points from malignant and 100 measured points from non-malignant areas of patients bladders in terms of their biopsy reports matching to the electrical impedance measurements. In all measurements, the impedivity of malignant area of bladder tissue was significantly higher than the impedivity of non-malignant area this tissue (<0.005.

  16. Bladder cancer detection using electrical impedance technique (tabriz mark 1).

    Science.gov (United States)

    Keshtkar, Ahmad; Salehnia, Zeinab; Keshtkar, Asghar; Shokouhi, Behrooz

    2012-01-01

    Bladder cancer is the fourth most common malignant neoplasm in men and the eighth in women. Bladder pathology is usually investigated visually by cystoscopy. In this technique, biopsies are obtained from the suspected area and then, after needed procedure, the diagnostic information can be taken. This is a relatively difficult procedure and is associated with discomfort for the patient and morbidity. Therefore, the electrical impedance spectroscopy (EIS), a minimally invasive screening technique, can be used to separate malignant areas from nonmalignant areas in the urinary bladder. The feasibility of adapting this technique to screen for bladder cancer and abnormalities during cystoscopy has been explored and compared with histopathological evaluation of urinary bladder lesions. Ex vivo studies were carried out in this study by using a total of 30 measured points from malignant and 100 measured points from non-malignant areas of patients bladders in terms of their biopsy reports matching to the electrical impedance measurements. In all measurements, the impedivity of malignant area of bladder tissue was significantly higher than the impedivity of non-malignant area this tissue (P < 0.005).

  17. Implementing a Web Browser with Phishing Detection Techniques

    CERN Document Server

    Jain, Aanchal

    2011-01-01

    Phishing is the combination of social engineering and technical exploits designed to convince a victim to provide personal information, usually for the monetary gain of the attacker. Phishing has become the most popular practice among the criminals of the Web. Phishing attacks are becoming more frequent and sophisticated. The impact of phishing is drastic and significant since it can involve the risk of identity theft and financial losses. Phishing scams have become a problem for online banking and e-commerce users. In this paper we propose a novel approach to detect phishing attacks. We implemented a prototype web browser which can be used as an agent and processes each arriving email for phishing attacks. Using email data collected over a period time we demonstrate data that our approach is able to detect more phishing attacks than existing schemes.

  18. Immuno-assay techniques for detecting yeasts in foods.

    Science.gov (United States)

    Middelhoven, W J; Notermans, S

    1993-06-25

    A brief literature review on immuno-assay of yeast cell wall antigens is given. Special attention is paid to extracellular, thermostable yeast antigens (EPS), which are released to the growth medium by many yeast species. The EPS of Saccharomyces cerevisiae and of Stephanoascus ciferrii (syn. Candida ciferrii) could be specifically and sensitively detected by a sandwich ELISA, using an IgG raised in rabbits immunized with the EPS of these yeasts. The EPS ELISA of three basidiomycetous yeasts tested was not specific, that of Geotrichum candidum was genus-specific but was not sensitive. The EPS of Zygosaccharomyces bailii could be detected in a highly specific competitive ELISA but not in a sandwich ELISA or in a latex agglutination test.

  19. On detection and visualization techniques for cyber security situation awareness

    Science.gov (United States)

    Yu, Wei; Wei, Shixiao; Shen, Dan; Blowers, Misty; Blasch, Erik P.; Pham, Khanh D.; Chen, Genshe; Zhang, Hanlin; Lu, Chao

    2013-05-01

    Networking technologies are exponentially increasing to meet worldwide communication requirements. The rapid growth of network technologies and perversity of communications pose serious security issues. In this paper, we aim to developing an integrated network defense system with situation awareness capabilities to present the useful information for human analysts. In particular, we implement a prototypical system that includes both the distributed passive and active network sensors and traffic visualization features, such as 1D, 2D and 3D based network traffic displays. To effectively detect attacks, we also implement algorithms to transform real-world data of IP addresses into images and study the pattern of attacks and use both the discrete wavelet transform (DWT) based scheme and the statistical based scheme to detect attacks. Through an extensive simulation study, our data validate the effectiveness of our implemented defense system.

  20. Detecting feature interactions in Web services with model checking techniques

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    As a platform-independent software system, a Web service is designed to offer interoperability among diverse and heterogeneous applications.With the introduction of service composition in the Web service creation, various message interactions among the atomic services result in a problem resembling the feature interaction problem in the telecommunication area.This article defines the problem as feature interaction in Web services and proposes a model checking-based detection method.In the method, the Web service description is translated to the Promela language - the input language of the model checker simple promela interpreter (SPIN), and the specific properties, expressed as linear temporal logic (LTL) formulas, are formulated according to our classification of feature interaction.Then, SPIN is used to check these specific properties to detect the feature interaction in Web services.

  1. A robust and fast generic voltage sag detection technique

    DEFF Research Database (Denmark)

    L. Dantas, Joacillo; Lima, Francisco Kleber A.; Branco, Carlos Gustavo C.;

    2015-01-01

    In this paper, a fast and robust voltage sag detection algorithm, named VPS2D, is introduced. Using the DSOGI, the algorithm creates a virtual positive sequence voltage and monitories the fundamental voltage component of each phase. After calculating the aggregate value in the o:;3-reference frame......, the algorithm can rapidly identify the starting and the ending of symmetric and asymmetric voltage sags, even if there are harmonics on the grid. Simulation and experimental results are given to validate the proposed algorithm....

  2. Survey of Insurance Fraud Detection Using Data Mining Techniques

    OpenAIRE

    Sithic, H. Lookman; T Balasubramanian

    2013-01-01

    With an increase in financial accounting fraud in the current economic scenario experienced, financial accounting fraud detection has become an emerging topics of great importance for academics, research and industries. Financial fraud is a deliberate act that is contrary to law, rule or policy with intent to obtain unauthorized financial benefit and intentional misstatements or omission of amounts by deceiving users of financial statements, especially investors and creditors. Data mining tec...

  3. Neutron-based techniques for detection of explosives and drugs

    CERN Document Server

    Kiraly, B; Csikai, J

    2001-01-01

    Systematic measurements were carried out on the possible use of elastically backscattered Pu-Be neutrons combined with the thermal neutron reflection method for the identification of land mines and illicit drugs via he detection of H, C, N, and O elements as their major constituents. While ur present results show that these methods are capable of indicating the anomalies in bulky materials and observation of the major elements, e termination of the exact atom fractions needs further investigation.

  4. The growth regularity and detective technique of collapse column

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Z. [Xingtai Coal Mining Bureau (China)

    1997-12-01

    The paper summarizes the growth regularity and the related factors of collapse column in Duongpang Coal Mine, introduces the applicability of roadway explorations, drillings and geophysical prospecting methods, expounds how to select an economic and quick exploration method according to the characteristics of each method and difference geological conditions for detecting the place, shape, size and water-bearing property of collapse column. 4 figs.

  5. Chemical Plume Detection with an Iterative Background Estimation Technique

    Science.gov (United States)

    2016-05-17

    this paper, we focus on cases where the plume is large (relative to the image ), and provide a method for handling this scenario. The method we develop...the locations of the events, the operation in (11) is a convolution of a binary image with a filter function h. To get an estimate of the probability...background statistics, including the mean and covariance. Diffuse plumes with a large spatial extent are particularly difficult to detect in single- image

  6. Down syndrome detection from facial photographs using machine learning techniques

    Science.gov (United States)

    Zhao, Qian; Rosenbaum, Kenneth; Sze, Raymond; Zand, Dina; Summar, Marshall; Linguraru, Marius George

    2013-02-01

    Down syndrome is the most commonly occurring chromosomal condition; one in every 691 babies in United States is born with it. Patients with Down syndrome have an increased risk for heart defects, respiratory and hearing problems and the early detection of the syndrome is fundamental for managing the disease. Clinically, facial appearance is an important indicator in diagnosing Down syndrome and it paves the way for computer-aided diagnosis based on facial image analysis. In this study, we propose a novel method to detect Down syndrome using photography for computer-assisted image-based facial dysmorphology. Geometric features based on facial anatomical landmarks, local texture features based on the Contourlet transform and local binary pattern are investigated to represent facial characteristics. Then a support vector machine classifier is used to discriminate normal and abnormal cases; accuracy, precision and recall are used to evaluate the method. The comparison among the geometric, local texture and combined features was performed using the leave-one-out validation. Our method achieved 97.92% accuracy with high precision and recall for the combined features; the detection results were higher than using only geometric or texture features. The promising results indicate that our method has the potential for automated assessment for Down syndrome from simple, noninvasive imaging data.

  7. Employing image processing techniques for cancer detection using microarray images.

    Science.gov (United States)

    Dehghan Khalilabad, Nastaran; Hassanpour, Hamid

    2017-02-01

    Microarray technology is a powerful genomic tool for simultaneously studying and analyzing the behavior of thousands of genes. The analysis of images obtained from this technology plays a critical role in the detection and treatment of diseases. The aim of the current study is to develop an automated system for analyzing data from microarray images in order to detect cancerous cases. The proposed system consists of three main phases, namely image processing, data mining, and the detection of the disease. The image processing phase performs operations such as refining image rotation, gridding (locating genes) and extracting raw data from images the data mining includes normalizing the extracted data and selecting the more effective genes. Finally, via the extracted data, cancerous cell is recognized. To evaluate the performance of the proposed system, microarray database is employed which includes Breast cancer, Myeloid Leukemia and Lymphomas from the Stanford Microarray Database. The results indicate that the proposed system is able to identify the type of cancer from the data set with an accuracy of 95.45%, 94.11%, and 100%, respectively.

  8. A New Technique to Detect Super-thin Clouds

    Science.gov (United States)

    Sun, Wenbo

    2016-04-01

    Super-thin clouds with optical depth smaller than ~0.3 exist globally and have significant effect on satellite remote sensing of surface temperature and atmospheric compositions, but are extremely difficult to be detected by satellite instruments. In this presentation, we report a novel method for detecting cloud particles in the atmosphere with measuring the polarized sunlight from the Earth-atmosphere system (Sun et al., 2014; Sun et al., 2015). We examined solar radiation backscattered from clouds with both satellite data and a radiative-transfer model. A distinct feature was found in the angle of linear polarization of solar radiation that is scattered from clouds at near-backscattering angles. The dominant electric field from the clear-sky Earth-atmosphere system is nearly parallel to the Earth surface at these scattering angles. However, when clouds are present, this electric field can rotate significantly away from the parallel direction. Our modeling results suggest that this polarization feature can be used to detect super-thin cirrus clouds having an optical depth of only ~0.06 and super-thin liquid water clouds having an optical depth of only ~0.01. Such clouds are too thin to be sensed using any current passive satellite instruments. This method could improve the detection of super-thin clouds and tremendously impact the remote sensing of clouds, aerosols, sea surface temperature, and atmospheric composition gases, and climate modeling. It also has potential to become an innovative satellite mission to advance Earth observation from space and improve scientific understanding of all clouds and cloud-aerosol interactions. Reference Wenbo Sun, Gorden Videen, and Michael I. Mishchenko, "Detecting super-thin clouds with polarized sunlight," Geophy. Res. Lett. 41, doi: 10.1002/2013GL058840 (2014). Wenbo Sun, Rosemary R. Baize, Gorden Videen, Yongxiang Hu, and Qiang Fu, "A method to retrieve super-thin cloud optical depth over ocean background with polarized

  9. Intrusion Detection Systems Based on Artificial Intelligence Techniques in Wireless Sensor Networks

    OpenAIRE

    2013-01-01

    Intrusion detection system (IDS) is regarded as the second line of defense against network anomalies and threats. IDS plays an important role in network security. There are many techniques which are used to design IDSs for specific scenario and applications. Artificial intelligence techniques are widely used for threats detection. This paper presents a critical study on genetic algorithm, artificial immune, and artificial neural network (ANN) based IDSs techniques used in wireless sensor netw...

  10. Techniques and methods for the low-energy neutrino detection

    Science.gov (United States)

    Ranucci, Gioacchino

    2016-04-01

    Low-energy neutrino physics and astrophysics has been one of the most active field of particle physics research over the past two decades, achieving important and sometimes unexpected results, which have paved the way for a bright future of further exciting studies. The methods, the techniques and the technologies employed for the construction of the many experiments which acted as important players in this area of investigation have been crucial elements to reach the many accumulated physics successes. The topic covered in this review is, thus, the description of the main features of the set of methodologies at the basis of the design, construction and operation of low-energy neutrino detectors.

  11. Defect detection in conducting materials using eddy current testing techniques

    Directory of Open Access Journals (Sweden)

    Brauer Hartmut

    2014-01-01

    Full Text Available Lorentz force eddy current testing (LET is a novel nondestructive testing technique which can be applied preferably to the identification of internal defects in nonmagnetic moving conductors. The LET is compared (similar testing conditions with the classical eddy current testing (ECT. Numerical FEM simulations have been performed to analyze the measurements as well as the identification of internal defects in nonmagnetic conductors. The results are compared with measurements to test the feasibility of defect identification. Finally, the use of LET measurements to estimate of the electrical conductors under test are described as well.

  12. Immunoblotting techniques with picogram sensitivity in cerebrospinal fluid protein detection.

    Science.gov (United States)

    Nespolo, A; Bianchi, G; Salmaggi, A; Lazzaroni, M; Cerrato, D; Malesani Tajoli, L

    1989-01-01

    Agarose isoelectric focusing followed by blotting with nitrocellulose, nylon or polyvinylidene difluoride membranes, and immunochemical detection of cerebrospinal fluid IgG with various combinations of antisera, was evaluated. Polyvinylidene difluoride proved to be an easy-to-handle and reliable membrane for protein blotting. Among immunochemical visualization reactions, the most sensitive employed biotinylated goat anti-human IgG followed by streptavidin colloidal gold conjugate and silver enhancement in 20% w/v urea, allowing a sensitivity of less then 1 picogram IgG/band.

  13. An immunity-based technique to detect network intrusions

    Institute of Scientific and Technical Information of China (English)

    PAN Feng; DING Yun-fei; WANG Wei-nong

    2005-01-01

    This paper briefly reviews other people's works on negative selection algorithm and their shortcomings. With a view to the real problem to be solved, authors bring forward two assumptions, based on which a new immune algorithm, multi-level negative selection algorithm, is developed. In essence, compared with Forrest's negative selection algorithm, it enhances detector generation efficiency. This algorithm integrates clonal selection process into negative selection process for the first time. After careful analyses, this algorithm was applied to network intrusion detection and achieved good results.

  14. Investigations on landmine detection by neutron-based techniques.

    Science.gov (United States)

    Csikai, J; Dóczi, R; Király, B

    2004-07-01

    Principles and techniques of some neutron-based methods used to identify the antipersonnel landmines (APMs) are discussed. New results have been achieved in the field of neutron reflection, transmission, scattering and reaction techniques. Some conclusions are as follows: The neutron hand-held detector is suitable for the observation of anomaly caused by a DLM2-like sample in different soils with a scanning speed of 1m(2)/1.5 min; the reflection cross section of thermal neutrons rendered the determination of equivalent thickness of different soil components possible; a simple method was developed for the determination of the thermal neutron flux perturbation factor needed for multi-elemental analysis of bulky samples; unfolded spectra of elastically backscattered neutrons using broad-spectrum sources render the identification of APMs possible; the knowledge of leakage spectra of different source neutrons is indispensable for the determination of the differential and integrated reaction rates and through it the dimension of the interrogated volume; the precise determination of the C/O atom fraction requires the investigations on the angular distribution of the 6.13MeV gamma-ray emitted in the (16)O(n,n'gamma) reaction. These results, in addition to the identification of landmines, render the improvement of the non-intrusive neutron methods possible.

  15. Investigations on landmine detection by neutron-based techniques

    Energy Technology Data Exchange (ETDEWEB)

    Csikai, J. E-mail: csikai@delfin.klte.hu; Doczi, R.; Kiraly, B

    2004-07-01

    Principles and techniques of some neutron-based methods used to identify the antipersonnel landmines (APMs) are discussed. New results have been achieved in the field of neutron reflection, transmission, scattering and reaction techniques. Some conclusions are as follows: The neutron hand-held detector is suitable for the observation of anomaly caused by a DLM2-like sample in different soils with a scanning speed of 1 m{sup 2}/1.5 min; the reflection cross section of thermal neutrons rendered the determination of equivalent thickness of different soil components possible; a simple method was developed for the determination of the thermal neutron flux perturbation factor needed for multi-elemental analysis of bulky samples; unfolded spectra of elastically backscattered neutrons using broad-spectrum sources render the identification of APMs possible; the knowledge of leakage spectra of different source neutrons is indispensable for the determination of the differential and integrated reaction rates and through it the dimension of the interrogated volume; the precise determination of the C/O atom fraction requires the investigations on the angular distribution of the 6.13 MeV gamma-ray emitted in the {sup 16}O(n,n'{gamma}) reaction. These results, in addition to the identification of landmines, render the improvement of the non-intrusive neutron methods possible.

  16. A Comparison of Techniques for Detecting Abnormal Change in Blogs

    Energy Technology Data Exchange (ETDEWEB)

    Furuta, Dr. Richard Keith [Texas A& M University; ShipmanIII, Dr. Frank Major [Texas A& M University; Bogen, Paul Logasa [ORNL

    2012-01-01

    Distributed collections are made of metadata entries that contain references to artifacts not controlled by the collection curators. These collections often have limited forms of change; for digital distributed collections, primarily creation and deletion of additional resources. However, there exists a class of digital collection that undergoes additional kinds of change. These collections consist of resources that are distributed across the Internet and brought together via hyperlinking. Resources in these collections can be expected to change as time goes on. Part of the difficulty in maintaining these collections is determining if a changed page is still a valid member of the collection. Others have tried to address this by defining a maximum allowed threshold of change, however, these methods treat change as a potential problem and treat web content as static despite its intrinsic dynamicism. Instead we acknowledge change on the web as a normal part of a web document and determine the difference between what a maintainer expects a page to do and what it actually does. In this work we evaluate options for extractors and analyzers from a suite of techniques against a human-generated ground-truth set of blog changes. The results of this work show a statistically significant improvement over traditional threshold techniques for our collection.

  17. Detecting Molecular Properties by Various Laser-Based Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hsin, Tse-Ming [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    Four different laser-based techniques were applied to study physical and chemical characteristics of biomolecules and dye molecules. These techniques are liole burning spectroscopy, single molecule spectroscopy, time-resolved coherent anti-Stokes Raman spectroscopy and laser-induced fluorescence microscopy. Results from hole burning and single molecule spectroscopy suggested that two antenna states (C708 & C714) of photosystem I from cyanobacterium Synechocystis PCC 6803 are connected by effective energy transfer and the corresponding energy transfer time is ~6 ps. In addition, results from hole burning spectroscopy indicated that the chlorophyll dimer of the C714 state has a large distribution of the dimer geometry. Direct observation of vibrational peaks and evolution of coumarin 153 in the electronic excited state was demonstrated by using the fs/ps CARS, a variation of time-resolved coherent anti-Stokes Raman spectroscopy. In three different solvents, methanol, acetonitrile, and butanol, a vibration peak related to the stretch of the carbonyl group exhibits different relaxation dynamics. Laser-induced fluorescence microscopy, along with the biomimetic containers-liposomes, allows the measurement of the enzymatic activity of individual alkaline phosphatase from bovine intestinal mucosa without potential interferences from glass surfaces. The result showed a wide distribution of the enzyme reactivity. Protein structural variation is one of the major reasons that are responsible for this highly heterogeneous behavior.

  18. Detection of special nuclear materials with the associate particle technique

    Science.gov (United States)

    Carasco, Cédric; Deyglun, Clément; Pérot, Bertrand; Eléon, Cyrille; Normand, Stéphane; Sannié, Guillaume; Boudergui, Karim; Corre, Gwenolé; Konzdrasovs, Vladimir; Pras, Philippe

    2013-04-01

    In the frame of the French trans-governmental R&D program against chemical, biological, radiological, nuclear and explosives (CBRN-E) threats, CEA is studying the detection of Special Nuclear Materials (SNM) by neutron interrogation with fast neutrons produced by an associated particle sealed tube neutron generator. The deuterium-tritium fusion reaction produces an alpha particle and a 14 MeV neutron almost back to back, allowing tagging neutron emission both in time and direction with an alpha particle position-sensitive sensor embedded in the generator. Fission prompt neutrons and gamma rays induced by tagged neutrons which are tagged by an alpha particle are detected in coincidence with plastic scintillators. This paper presents numerical simulations performed with the MCNP-PoliMi Monte Carlo computer code and with post processing software developed with the ROOT data analysis package. False coincidences due to neutron and photon scattering between adjacent detectors (cross talk) are filtered out to increase the selectivity between nuclear and benign materials. Accidental coincidences, which are not correlated to an alpha particle, are also taken into account in the numerical model, as well as counting statistics, and the time-energy resolution of the data acquisition system. Such realistic calculations show that relevant quantities of SNM (few kg) can be distinguished from cargo and shielding materials in 10 min acquisitions. First laboratory tests of the system under development in CEA laboratories are also presented.

  19. Attacks Prevention and Detection Techniques In MANET: A Survey

    Directory of Open Access Journals (Sweden)

    Pranjali D. Nikam,

    2014-11-01

    Full Text Available Wireless sensor network is a set of distributed sensor nodes. Which are randomly deployed in geographical area to capture climatic changes like temperature, humidity and pressure. In Wireless Network MANET is a Mobile Ad-Hoc Networks which is a one self-configurable network. MANET is a collection of Wireless mobile node which is dynamically moves from one location to another location. Both attacks Active as well as Passive attacks is in MANET. It doesn’t have a static structure. Security for wireless network is much difficult as compare to wired networks. In last few years many security and attacks issue are face many researchers in MANET. Attacks like Packet dropping attack, Black-Hole attack, Denial of Service attack, wormhole attacks and Packet modification attacks found in MANET. At the time of data communication all the above mentioned attacks access data easily without permission. To solve the problem of attacks in MANET and secure data communication use Intrusion Detection System. In This paper propose the survey of different kinds of attacks on MANET and Wireless sensor networks. This paper helps to young researcher for implement new hybrid algorithm for secure intrusion detection in MANET.

  20. Early Detection of Lung Cancer Using Neural Network Techniques

    Directory of Open Access Journals (Sweden)

    Prashant Naresh

    2014-08-01

    Full Text Available Effective identification of lung cancer at an initial stage is an important and crucial aspect of image processing. Several data mining methods have been used to detect lung cancer at early stage. In this paper, an approach has been presented which will diagnose lung cancer at an initial stage using CT scan images which are in Dicom (DCM format. One of the key challenges is to remove white Gaussian noise from the CT scan image, which is done using non local mean filter and to segment the lung Otsu’s thresholding is used. The textural and structural features are extracted from the processed image to form feature vector. In this paper, three classifiers namely SVM, ANN, and k-NN are applied for the detection of lung cancer to find the severity of disease (stage I or stage II and comparison is made with ANN, and k-NN classifier with respect to different quality attributes such as accuracy, sensitivity(recall, precision and specificity. It has been found from results that SVM achieves higher accuracy of 95.12% while ANN achieves 92.68% accuracy on the given data set and k-NN shows least accuracy of 85.37%. SVM algorithm which achieves 95.12% accuracy helps patients to take remedial action on time and reduces mortality rate from this deadly disease.

  1. Neural network technique for detecting emergency states in neurosurgical patients.

    Science.gov (United States)

    Swiercz, M; Mariak, Z; Lewko, J; Chojnacki, K; Kozlowski, A; Piekarski, P

    1998-11-01

    The problem of reliable detection of life-threatening situations in the neurosurgical patient undergoing treatment in the ICU is still far from reaching a satisfactory solution, although several methods of clinical and instrumental evaluation have recently been developed for the early detection of oncoming signs of danger. Continuous monitoring of intracranial pressure (ICP) provides neurosurgeons with valuable information about the current condition of the patient. However, it is increasingly felt that traditional methods of extracting information from the ICP signal have reached their natural limits, mostly because of difficulties in fitting the appropriate mathematical model to this non-linear and non-stationary process. Successful implementations of artificial neural networks in many medical tasks have encouraged the application of this method of ICP processing. Two problems are considered: the prediction of trends in ICP, and recognition of the configuration of unfavourable symptoms likely to signal danger for the neurosurgical patient. The construction of neural network predictors of ICP trends is based on wavelet pre-processing of the original signal. The approach to the second task involves pre-processing of the ICP with spectral and statistical methods and classification of the extracted features of the current signal on an arbitrarily selected scale of danger.

  2. Indirect fluorometric detection techniques on thin layer chromatography and effect of ultrasound on gel electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Yinfa, Ma.

    1990-12-10

    Thin-layer chromatography (TLC) is a broadly applicable separation technique. It offers many advantages over high performance liquid chromatography (HPLC), such as easily adapted for two-dimensional separation, for whole-column'' detection and for handling multiple samples, etc. However, due to its draggy development of detection techniques comparing with HPLC, TLC has not received the attention it deserves. Therefore, exploring new detection techniques is very important to the development of TLC. It is the principal of this dissertation to present a new detection method for TLC -- indirect fluorometric detection method. This detection technique is universal sensitive, nondestructive, and simple. This will be described in detail from Sections 1 through Section 5. Section 1 and 3 describe the indirect fluorometric detection of anions and nonelectrolytes in TLC. In Section 2, a detection method for cations based on fluorescence quenching of ethidium bromide is presented. In Section 4, a simple and interesting TLC experiment is designed, three different fluorescence detection principles are used for the determination of caffeine, saccharin and sodium benzoate in beverages. A laser-based indirect fluorometric detection technique in TLC is developed in Section 5. Section 6 is totally different from Sections 1 through 5. An ultrasonic effect on the separation of DNA fragments in agarose gel electrophoresis is investigated. 262 refs.

  3. Detecting Defects in Aircraft Materials by Nuclear Technique (pas)

    Science.gov (United States)

    Badawi, Emad. A.

    Positron annihilation spectroscopy (PAS) is one of the nuclear techniques used in material science. The present measurements are used to study the behavior of defect concentration in one of the most important materials aluminum alloys which is the 7075 alloy. It has been shown that positrons can become trapped at imperfect locations in solids and their mean lifetime can be influenced by changes in the concentration of such defects. No changes have been observed in the mean lifetime values after the saturation of defect concentration. The mean lifetime and trapping rates are studied for samples deformed up to 58.3%. The concentration of defect range vary from 1015 to 1018cm-3 at the thickness reduction from 2.3 to 58.3%. The dislocation density varies from 108 to 1011cm/cm3.

  4. 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.

  5. Cyanoacrylate tissue glue for wound repair in early posttrabeculectomy conjunctival bleb leak: a case series

    Directory of Open Access Journals (Sweden)

    Haslinda AR

    2015-07-01

    Full Text Available Abdul-Rahim Haslinda, Yaakub Azhany, Rasid Noor-Khairul, Embong Zunaina, Ahmad-Tajudin Liza-Sharmini Department of Ophthalmology, School of Medical Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia Abstract: We demonstrated a noninvasive management of early bleb leak following trabeculectomy using cyanoacrylate tissue glue (CATG. Three patients who underwent augmented trabeculectomy with mitomycin C with early bleb leak between January 2009 and June 2010 were reviewed. Case 1 and Case 2 exhibited bleb leak on postoperative Day 1 and Case 3 showed leak on follow-up at postoperative Day 7. Case 1 was successfully sealed with CATG at postoperative Day 3, after failed pressure padding and bandage contact lens. Case 2 was successfully sealed with CATG at postoperative Day 3, after failed pressure padding and conjunctiva flap resuturing. In Case 3, the leaking conjunctival flap was managed with combined techniques of resuturing and applying CATG at postoperative Day 9, after failed pressure padding. During leakage, the intraocular pressure was low (6–8 mmHg in all three cases, with shallow anterior chamber depth and absence of other complications such as choroidal detachment, hypotony maculopathy, or endophthalmitis. Foreign body sensation was the main complaint following the procedure. No clinical allergy reaction was documented. CATG may serve as a potential adjunctive and effective method in the management of posttrabeculectomy early bleb leak. Keywords: cyanoacrylate tissue glue, bleb leak, trabeculectomy, mitomycin C

  6. 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

  7. Techniques of EMG signal analysis: detection, processing, classification and applications

    Science.gov (United States)

    Hussain, M.S.; Mohd-Yasin, F.

    2006-01-01

    Electromyography (EMG) signals can be used for clinical/biomedical applications, Evolvable Hardware Chip (EHW) development, and modern human computer interaction. EMG signals acquired from muscles require advanced methods for detection, decomposition, processing, and classification. The purpose of this paper is to illustrate the various methodologies and algorithms for EMG signal analysis to provide efficient and effective ways of understanding the signal and its nature. We further point up some of the hardware implementations using EMG focusing on applications related to prosthetic hand control, grasp recognition, and human computer interaction. A comparison study is also given to show performance of various EMG signal analysis methods. This paper provides researchers a good understanding of EMG signal and its analysis procedures. This knowledge will help them develop more powerful, flexible, and efficient applications. PMID:16799694

  8. 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.

  9. 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.

  10. Detection of apoptosis in pemphigus vulgaris by TUNEL technique*

    Science.gov (United States)

    Cuevas-Gonzalez, Juan Carlos; Vega-Memíje, Maria Elisa; García-Vázquez, Francisco Javier; Aguilar-Urbano, Marco António

    2016-01-01

    Background Pemphigus is part of a group of blistering diseases that affect the skin and mucous membranes. Based on its autoimmune origin, autoantibodies develop in pemphigus that are directed toward cell surface components of keratinocytes. However, some data cannot be explained, such as the lack of a relationship between autoantibody levels and the severity of clinical manifestations, treatment resistance, the presence of inflammatory infiltrates and the potential occurrence of apoptosis as determinants of vesicle formation. Objective To examine the presence of apoptosis in pemphigus vulgaris by TUNEL technique. Methods In this cross-sectional study, we selected 15 paraffin-embedded tissues from subjects who were diagnosed with pemphigus vulgaris by hematoxylin and eosin staining. The samples were subjected to TUNEL assay and examined under an Olympus BX61 fluorescence microscope. Positivity was categorized dichotomously, and the statistical analysis was performed using the X2 test. Results Positivity was observed in basal layer cells in 14 (93.3%) cases. In 13 (86.7%) of the positive cases, we noted espinosum and granular layers that formed the blister roof, and in 12 cases (80%), positive acantholytic cells were observed. Conclusions TUNEL positivity was observed in pemphigus vulgaris, implicating apoptosis in the pathophysiology of this condition, which can help guide the development of apoptotic blockers as therapeutics. PMID:27438195

  11. Optimized digital filtering techniques for radiation detection with HPGe detectors

    Science.gov (United States)

    Salathe, Marco; Kihm, Thomas

    2016-02-01

    This paper describes state-of-the-art digital filtering techniques that are part of GEANA, an automatic data analysis software used for the GERDA experiment. The discussed filters include a novel, nonlinear correction method for ballistic deficits, which is combined with one of three shaping filters: a pseudo-Gaussian, a modified trapezoidal, or a modified cusp filter. The performance of the filters is demonstrated with a 762 g Broad Energy Germanium (BEGe) detector, produced by Canberra, that measures γ-ray lines from radioactive sources in an energy range between 59.5 and 2614.5 keV. At 1332.5 keV, together with the ballistic deficit correction method, all filters produce a comparable energy resolution of ~1.61 keV FWHM. This value is superior to those measured by the manufacturer and those found in publications with detectors of a similar design and mass. At 59.5 keV, the modified cusp filter without a ballistic deficit correction produced the best result, with an energy resolution of 0.46 keV. It is observed that the loss in resolution by using a constant shaping time over the entire energy range is small when using the ballistic deficit correction method.

  12. Optimized digital filtering techniques for radiation detection with HPGe detectors

    CERN Document Server

    Salathe, M

    2015-01-01

    This paper describes state-of-the-art digital filtering techniques that are part of the tool kit GEANA which is used as a fast automatic data validation tool for the GERDA experiment. The discussed filters include a novel, nonlinear correction method for ballistic deficits, which is combined with one of three shaping filters: the pseudo-Gaussian, a modified trapezoidal, or a modified cusp filter. The performance of the filters is demonstrated using a 762 g high purity germanium detector that measures gamma-ray lines from radioactive sources in an energy range between 59 and 2615 keV. The modified cusp filter was found to be most optimal for individual gamma-ray lines. Furthermore, it was observed, that even though, the shaping time that minimizes the energy resolution is energy dependent, the loss in resolution by using a constant shaping time over the entire energy range is small, i.e. less than 32 eV for the pseudo-Gaussian filter. This together with good energy resolutions, e.g. 1.59 keV at 1333 keV, this ...

  13. Detection of asphalt pavement cracks using remote sensing techniques

    Science.gov (United States)

    Mettas, Christodoulos; Agapiou, Athos; Themistocleous, Kyriacos; Neocleous, Kyriacos; Hadjimitsis, Diofantos G.

    2016-10-01

    Deterioration of asphalt road pavements is inevitable throughout its life cycle. There are several types of deterioration that take place on these surfaces, like surface defects and deformations. One of the most common asphalt defects is cracking. Fatigue, transverse, longitudinal, reflective, edge, block and slippage are types of cracking that can be observed anywhere in the world. Monitoring and preventative/periodic maintenance of these types of wears are two very important actions that have to take place to avoid "costly" solutions. This paper aims to introduce the spectral characteristics of uncracked (healthy) and cracked asphalt surfaces which can give a new asphalt crack index. This is performed through remote sensing applications in the area of asphalt pavements. Multispectral images can be elaborated using the index to enhance crack marks on asphalt surfaces. Ground spectral signatures were acquired from both uncracked and cracked asphalted areas of Cyprus (Limassol). Evaluation separability indices can be used to identify the optimum wavelength regions that can distinguish better the uncracked and cracked asphalt surfaces. The results revealed that the spectral sensitivity for the enhancement of cracked asphalt was detected using the Euclidean, Mahalanobis and Cosine Distance Indices in the Vis range (approximately at 450 nm) and in the SWIR 1 range (approximately at 1750 nm).

  14. Detection of formestane abuse by mass spectrometric techniques.

    Science.gov (United States)

    de la Torre, Xavier; Colamonici, Cristiana; Curcio, Davide; Jardines, Daniel; Molaioni, Francesco; Parr, Maria Kristina; Botrè, Francesco

    2014-01-01

    Formestane (4-hydroxy-androstenedione) is an aromatase inhibitor prohibited in sports and included, since 2004, in the list of prohibited substances updated yearly by the World Anti-Doping Agency (WADA). Since the endogenous production of formestane has been described, it is mandatory for the anti-doping laboratories to use isotope ratio mass spectrometry (IRMS) to establish the exogenous origin before issuing an adverse analytical finding. The described IRMS methods for formestane detection are time-consuming, requiring usually two consecutive liquid chromatographic sample purifications in order to have final extracts of adequate purity before the mass spectrometric analysis. After establishing a procedure for the determination of the origin of formestane by IRMS without the need of derivatization, and integrated in the overall analytical strategy of the laboratory for pseudo-endogenous steroids, a mass spectrometric analysis by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS) of formestane metabolites was carried out in order to investigate whether other biomarkers of formestane abuse could be integrated in order to avoid time-consuming and expensive IRMS confirmations for formestane. From the metabolic studies performed, the inclusion of 3β,4α-dihydroxy-5α-androstan-17-one (4α-hydroxy-epiandosterone) in the routine GC-MS procedures has demonstrated to be diagnostic in order to reduce the number of unnecessary confirmations of the endogenous origin of formestane.

  15. Detection and classification of stress using thermal imaging technique

    Science.gov (United States)

    Hong, Kan; Yuen, Peter; Chen, Tong; Tsitiridis, Aristeidis; Kam, Firmin; Jackman, James; James, David; Richardson, Mark; Oxford, William; Piper, Jonathan; Thomas, Francis; Lightman, Stafford

    2009-09-01

    This paper reports how Electro-Optics (EO) technologies such as thermal and hyperspectral [1-3] imaging methods can be used for the detection of stress remotely. Emotional or physical stresses induce a surge of adrenaline in the blood stream under the command of the sympathetic nerve system, which, cannot be suppressed by training. The onset of this alleviated level of adrenaline triggers a number of physiological chain reactions in the body, such as dilation of pupil and an increased feed of blood to muscles etc. The capture of physiological responses, specifically the increase of blood volume to pupil, have been reported by Pavlidis's pioneer thermal imaging work [4-7] who has shown a remarkable increase of skin temperature in the periorbital region at the onset of stress. Our data has shown that other areas such as the forehead, neck and cheek also exhibit alleviated skin temperatures dependent on the types of stressors. Our result has also observed very similar thermal patterns due to physical exercising, to the one that induced by other physical stressors, apparently in contradiction to Pavlidis's work [8]. Furthermore, we have found patches of alleviated temperature regions in the forehead forming patterns characteristic to the types of stressors, dependent on whether they are physical or emotional in origin. These stress induced thermal patterns have been seen to be quite distinct to the one resulting from having high fever.

  16. Interferometric Techniques for Gravitational Wave Detection in Space

    Science.gov (United States)

    Stebbins, Robin T; Bender, Peter L.

    2000-01-01

    The Laser Interferometer Space Antenna (LISA) mission will detect gravitational waves from galactic and extragalactic sources, most importantly those involving supermassive black holes. The primary goal of this project is to investigate stability and robustness issues associated with LISA interferometry. We specifically propose to study systematic errors arising from: optical misalignments, optical surface errors, thermal effects and pointing tolerances. This report covers the first fiscal year of the grant, from January 1st to December 31st 1999. We have employed an optical modeling tool to evaluate the effect of misplaced and misaligned optical components. Preliminary results seem to indicate that positional tolerances of one micron and angular tolerances of 0.6 millirad produce no significant effect on the achievable contrast of the interference pattern. This report also outlines research plans for the second fiscal year of the grant, from January 1st to December 31st 2000. Since the work under NAG5-6880 has gone more rapidly than projected, our test bed interferometer is operational, and can be used for measurements of effects that cause beam motion. Hence, we will design, build and characterize a sensor for measuring beam motion, and then install it. We are also planning a differential wavefront sensor based on a quadrant photodiode as a first generation sensor.

  17. High throughput interferometric Doppler technique for planet detection

    Science.gov (United States)

    Mahadevan, Suvrath

    We have developed a novel instrument called the Exoplanet Tracker (ET) that can measure precise differential radial velocities, as well as barycentric radial velocities. ET is installed at the Kitt Peak 2.1 meter telescope and uses a Michelson interferometer in series with a medium resolution spectrograph. This instrument allows stellar radial velocities to be measured precisely without the use of a high resolution spectrograph. This allows the instrument to be very efficient in collecting light from the telescope. ET can achieve a radial velocity precision of 5-10 m s-1 over a 10 day observing run. A survey for extrasolar planets using the ET instrument has led to the detection of radial velocity variability for the star HD102195. Using photometry, CaII HK measurements, and precision radial velocities we demonstrate that these radial velocity variations are caused by a giant planet in a 4.11 day orbit around HD102195. A prototype monolithic interferometer has also been built for the ET instrument and is capable of delivering precise radial velocities. A large multi-object radial velocity instrument based on the ET instrument has been built and installed at the wide field Sloan 2.5 m telescope. This instrument, called the W. M. Keck Exoplanet Tracker, is capable of obtaining precise radial velocities for 59 stars simultaneously. Over the next few years this multi-object instrument will be used to conduct an All Sky ExoPlanet Survey capable of efficiently searching thousands of stars for planets.

  18. Long QT syndrome mutation detection by SNaPshot technique.

    Science.gov (United States)

    Edelmann, Jeanett; Schumann, Stefanie; Nastainczyk, Marina; Husser-Bollmann, Daniela; Lessig, Rüdiger

    2012-11-01

    Long QT syndrome (LQTS) is a cardiac disorder with an abnormality of cardiac rhythm associated with sudden death especially in younger, apparently healthy individuals. If there is no clear cause of death detectable during comprehensive coroner's inquest (autopsy-negative cases), you have to consider LQTS and other heritable arrhythmia syndromes. A molecular genetic screening regarding mutations in associated genes can help to ensure the cause of death and to protect affected family members. Genetic testing of LQTS, currently performed mainly by sequencing, is still very expensive and time consuming. With this study we present a rapid and reasonable method for the simultaneously screening of some of the most common mutations associated with LQTS, focused on the KCNQ1 and KCNH2 genes. With the method of SNaPshot minisequencing, a total of 58 mutations were analyzed in four multiplex assays which were successfully established and optimized. The comparison with samples previously analyzed by direct sequencing showed concordance. Furthermore, autopsy-negative cases were tested but no mutations could be observed in any of the specimen. The presented method is well suitable for LQTS mutation screening. An enhancement to further mutations and population-based investigations regarding mutation frequencies should be the aim of prospective studies.

  19. Predicting detection limits of enzyme-linked immunosorbent assay (ELISA) and bioanalytical techniques in general.

    Science.gov (United States)

    Zhang, Shiyun; Garcia-D'Angeli, Alexa; Brennan, Joseph P; Huo, Qun

    2014-01-21

    The detection limit is one of the most important performance parameters for bioanalytical techniques. Here we present a generic method to estimate the detection limit of biomolecular assays based on a step-by-step analysis of the assay procedure. Enzyme-linked immunosorbent assay (ELISA) is used here as an example; however, much of the information presented in this article may be applied to other types of biomolecular assays and analytical techniques. A clear understanding of what affects the detection limit can help researchers to evaluate different bio-analytical techniques properly, and to design better strategies to optimize and achieve the best analytical performance.

  20. 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.