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Sample records for check valve monitoring

  1. Recent improvements in check valve monitoring methods

    International Nuclear Information System (INIS)

    In support of the NRC Nuclear Plant Aging Research (NPAR) program, ORNL has carried out an evaluation of three check valve monitoring methods: acoustic emission, ultrasonic inspection, and magnetic flux signature analysis (MFSA). This work has focused on determining the capabilities of each method to provide diagnostic information useful in determining check valve aging and service wear effects (degradation) and undesirable operating modes. In addition, as part of the ORNL Advanced Diagnostic Engineering Research and Development Center (ADEC), two noval nonintrusive monitoring methods were developed (external ac- and dc-magnetic monitoring) that provide several improvements over the other methods. None of the examined methods could, by themselves, monitor the instantaneous position and motion of check valve internals and valve leakage; however, the combination of acoustic emission monitoring with one of the other methods provides the means to determine vital check valve operational information. This paper describes the benefits and limitations associated with each method and includes recent laboratory and field test data to illustrate the capabilities of these methods to detect simulated check valve degradation. 3 refs., 22 figs., 4 tabs

  2. Application of acoustic emission technique for check valve monitoring

    International Nuclear Information System (INIS)

    Very limited choice is available in monitoring the health of check valves during service. Ultrasonics, magnetic flux leakage and acoustic emission (AE) monitoring are three methods, of which AE is the prominent. The paper describes work done on swing check valves in the ECCS circuit of Cirus using AE. It indicates that the valves can be monitored for any abnormal behaviour during their stable operation and during opening and closing. AE can also sense any abnormality at the hinge pin, hinge arm, disc etc., if they give AE emission. However, many of these may require background data from a spare valve of similar design or a working stand by. In absence of such a valve, data from the present study will be used as a baseline data for comparison with signatures taken during future inspections. (author). 3 refs., 5 figs., 1 tab

  3. Check valve

    International Nuclear Information System (INIS)

    A check valve for use in a GDCS of a nuclear reactor and having a motor driven disk including a rotatable armature for rotating the check valve disk over its entire range of motion is described. In one embodiment, the check valve includes a valve body having a coolant flow channel extending therethrough. The coolant flow channel includes an inlet end and an outlet end. A valve body seat is located on an inner surface of the valve body. The check valve further includes a disk assembly, sometimes referred to as the motor driven disc, having a counterweight and a disk shaped valve. The disk valve includes a disk base having a seat for seating with the valve body seat. The disk assembly further includes a first hinge pin member which extends at least partially through the disk assembly and is engaged to the disk. The disk valve is rotatable relative to the first hinge pin member. The check valve also includes a motor having a stator frame with a stator bore therein. An armature is rotatably positioned within the stator bore and the armature is coupled to the disk valve to cause the disk valve to rotate about its full range of motion. 5 figs

  4. The use of check valve performance data to support new concepts (probabilistic risk assessment, condition monitoring) for check valve program

    Energy Technology Data Exchange (ETDEWEB)

    Hart, K.A.; Gower, D.

    1996-12-01

    The concept of developing an integrated check valve database based on the Nuclear Power Reliability Data System (NPRDS) data was presented at the last Symposium. The Nuclear Industry Check Valve Group (NIC), working in cooperation with the Oak Ridge National Laboratory (ORNL), has completed an operational database of check valve performance from 1984 to the present. NIC has committed to the nuclear industry to periodically update the data and maintain this information accessible. As the new concepts of probabilistic risk analysis and condition monitoring are integrated into the American Society of Mechanical Engineers (ASME) Code, a critical element will be performance data. From check valve performance data, feasible failure modes and rates can be established. When a failure rate or frequency of failures can be established based on a significant enough population (sampling), a more solid foundation for focusing resources and determining appropriate frequencies and testing can be determined. The presentation will give the updated status of the NIC Check Valve Performance Database covering (1) methodology used to combine the original ORNL data; (2) process/controls established for continuing update and refinement of the data; (3) discussion of how this data is being utilized by (a) OM-22 for condition monitoring, and (b) risk-based inservice testing work of Westinghouse Owners` Group; and (4) results/trends of data evaluations. At the 1994 Symposium, ORNL provided an update as of 1991 to their original work of 1984 -1990 which they had performed to characterize check valve degradations and failures in the nuclear industry. These characterizations will be updated to 1995 and additional reviews provided to give insight into the current condition and trends of check valve performance.

  5. Check valves aging assessment

    International Nuclear Information System (INIS)

    In support of the NRC Nuclear Plant Aging Research (NPAR) program, the Oak Ridge National Laboratory (ORNL) has carried out an assessment of several check value diagnostic monitoring methods, in particular, those based on measurements of acoustic emission, ultrasonics, and magnetic flux. The evaluations have focussed on the capabilities of each method to provide information useful in determining check valve aging and service wear effects, check valve failures, and undesirable operating modes. This paper describes the benefits and limitations associated with each method and includes recent laboratory and field test data, including data obtained from the vendors who recently participated in a comprehensive series of tests directed by a nuclear industry users group. In addition, as part of the ORNL Advanced Diagnostic Engineering Research and Development Center (ADEC), two novel nonintrusive monitoring methods were developed that provide several unique capabilities. These methods, based on external ac- an dc-magnetic monitoring are also described. None of the examined methods could, by themselves, monitor both the instantaneous position and motion of check valve internals and valve leakage; however, the combination of acoustic emission monitoring with one of the other methods provides the means to determine vital check valve operational information

  6. A study of condition monitoring of check valve using acoustic emission and neural network technique

    International Nuclear Information System (INIS)

    The check valve is one of typical component being extensively used in safety systems of nuclear power plants. The failures of check valves have resulted in significant maintenance efforts, on occasion, have resulted in water hammer, over-pressurization of low-pressure systems, and damage to flow system components. The objective of this research is to demonstrate condition-monitoring system based on acoustic emission, AE detection that can provide timely detection of check valve degradation and service aging so that maintenance/ replacement could be preformed prior to loss of safety function. This work is also focused on the capability of neural network technique to provide diagnostic information useful in determining check valve aging and degradation, check valve failures and undesirable operating modes

  7. Acoustic emission condition monitoring of a nuclear power plant check valve using artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joon Hyun; Lee, Min Rae [Pusan National University, Pusan (Korea, Republic of); Kim, Jung Teak [Korea Atomic Energy Research Institute, Taejeon (Korea, Republic of)

    2005-11-15

    In this study, an advanced condition monitoring technique based on acoustic emission (AE) detection and artificial neural networks was applied to a check valve, one of the components being used extensively in a safety system of a nuclear power plant (Npp). AE testing for a check valve under controlled flow loop conditions was performed to detect and evaluate disk movement for valve degradation such as wear and leakage due to foreign object interference in a check valve. It is clearly demonstrated that the evaluation of different types of failure modes such as disk wear and check valve leakage were successful by systematically analyzing the characteristics of various AE parameters. It is also shown that the leak size can be determined with an artificial neural network.

  8. Acoustic emission condition monitoring of a nuclear power plant check valve using artificial neural networks

    International Nuclear Information System (INIS)

    In this study, an advanced condition monitoring technique based on acoustic emission (AE) detection and artificial neural networks was applied to a check valve, one of the components being used extensively in a safety system of a nuclear power plant (Npp). AE testing for a check valve under controlled flow loop conditions was performed to detect and evaluate disk movement for valve degradation such as wear and leakage due to foreign object interference in a check valve. It is clearly demonstrated that the evaluation of different types of failure modes such as disk wear and check valve leakage were successful by systematically analyzing the characteristics of various AE parameters. It is also shown that the leak size can be determined with an artificial neural network

  9. Condition monitoring of a check valve for nuclear power plants by means of acoustic emission technique

    International Nuclear Information System (INIS)

    The primary object of this work is to investigate advanced condition monitoring systems based on acoustic emission (AE) detection that can provide timely detection of check valve degradation and service aging so that maintenance/replacement could be performed prior to loss of safety function. The research is focused on the capability of AE technique to provide diagnostic information useful in determining check valve aging and degradation, check valve failures and undesirable operating modes. The systematic approach to classify the dynamic responses of AE signatures associated with typical failure modes of check valve for nuclear power plants is performed in this study. The characteristics of AE signature responses of internal parts of check valves due to local aging and degradation is analyzed by extracting effective AE parameters. This work also includes the investigation and adaptation of several advanced sensor technologies such as accelerometer and advanced ultrasonic technique. In addition, this work will develop advanced sophisticated signal processing, noise reduction, and pattern recognition techniques and algorithms from check valve degradation. (author)

  10. Swing check valve

    International Nuclear Information System (INIS)

    A swing check valve which includes a valve body having an inlet and outlet is described. A recess in the valve body designed to hold a seal ring and a check valve disc swingable between open and closed positions. The disc is supported by a high strength wire secured at one end in a support spacer pinned through bearing blocks fixed to the valve body and at its other end in a groove formed on the outer peripheral surface of the disc. The parts are designed and chosen such to provide a lightweight valve disc which is held open by minimum velocity of fluid flowing through the valve which thus reduces oscillations and accompanying wear of bearings supporting the valve operating parts. (Auth.)

  11. Keeping valves in check

    International Nuclear Information System (INIS)

    Check valves are located in almost all safety and non-safety related fluid systems in a nuclear power plant. Malfunction or failure of these valves during plant operations, or in some cases under cold shutdown conditions, can seriously affect plant safety and result in costly, time-consuming maintenance. A major cause of check valve failure in the past has been excessive wear of internal components due to high disc flutter. Valve operation under conditions that cause the valve disc and hinge arm to oscillate or flutter can lead to degradations which, if undetected and not corrected, may result in malfunction or failure. Checkmate II, a portable, non-intrusive diagnostic system, has been developed to test various types of check valves using patented ultrasonic testing technology. The system comprises a computer, ultrasonic oscilloscope, transducers, and supporting hardware, and can identify many different phenomena, including: disc position and disc flutter; backstop and seat tapping; relative motion between hinge arm and disc; hinge pin wear and uneven hinge pin wear; disc stud wear and loosened stud nuts; combined stud and hinge pin wear, stuck and missing discs; broken springs. (author)

  12. A study of the characteristics of the acoustic emission signals for condition monitoring of check valves in nuclear power plants

    International Nuclear Information System (INIS)

    The objective of this study is to demonstrate that a condition-monitoring system based on acoustic emission (AE) detection can provide timely detection of check valve degradation and service aging so that maintenance or replacement can be preformed prior to the loss of safety function. This research is focused on the investigation and understanding of the capability of the acoustic emission technique to provide diagnostic information on check valve failures. AE testing for a check valve under controlled flow loop conditions was performed to detect and valve degradation such as wear and leakage due to foreign object interference. It is clearly demonstrated that the distinction of different types of failure were successful by systematically analyzing the characteristics of various AE parameters

  13. A study of the characteristics of the acoustic emission signals for condition monitoring of check valves in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joon-Hyun [School of Mechanical Engineering, Pusan National University, San 30 Jangjeon-dong, Kumjeong-gu, Pusan 609-735 (Korea, Republic of)]. E-mail: johlee@pusan.ac.kr; Lee, Min-Rae [Department of Mechanical Design Engineering, Pusan National University (Korea, Republic of); Kim, Jung-Teak [Man-Machine Interface System Team, Korea Atomic Energy Research Institute Yuseong, Daejeon 305-600 (Korea, Republic of); Luk, Vincent [Sandia National Laboratories, Risk and Reliability Analysis Department, Albuquerque, NM (United States); Jung, Yoong-Ho [School of Mechanical Engineering, Pusan National University, San 30 Jangjeon-dong, Kumjeong-gu, Pusan 609-735 (Korea, Republic of)

    2006-07-15

    The objective of this study is to demonstrate that a condition-monitoring system based on acoustic emission (AE) detection can provide timely detection of check valve degradation and service aging so that maintenance or replacement can be preformed prior to the loss of safety function. This research is focused on the investigation and understanding of the capability of the acoustic emission technique to provide diagnostic information on check valve failures. AE testing for a check valve under controlled flow loop conditions was performed to detect and valve degradation such as wear and leakage due to foreign object interference. It is clearly demonstrated that the distinction of different types of failure were successful by systematically analyzing the characteristics of various AE parameters.

  14. Action plans for motor-operated valves and check valves

    International Nuclear Information System (INIS)

    The proper performance of motor-operated valves (MOVs) and check valves is necessary for the safety operation of a nuclear power plant. Problems have been experienced, however, with these valves for many years. Currently, the US Nuclear Regulatory Commission (NRC) and the nuclear industry have a number of activities under way to provide assurance that MOVs and check valves will successfully perform their safety functions when needed. The Mechanical Engineering Branch (EMEB) of the NRC Office of Nuclear Reactor Regulation has been assigned the responsibility of coordinating NRC activities and monitoring industry activities regarding MOVs and check valves. To meet this responsibility, EMEB has prepared action plans to provide assurance of the proper performance of these valves. Among the staff activities described in the action plans is the consideration of the need to revise the regulations to clarify the inservice testing (IST) requirements for these valves. The need for regulatory guidance for the development of acceptable IST programs, as well as for other licensee activities relating to the performance of MOVs and check valves, will also be evaluated. In addition, NRC personnel will have to verify, in a consistent manner, implementation of licensee commitments in response to NRC generic letters and bulletins. Another important aspect of the action plans is the provision for the NRC staff to provide assistance, where appropriate, to the industry in its efforts to address MOV and check valve issues. Finally, the action plans include a tentative schedule for accomplishing the described staff activities

  15. Non intrusive check valve diagnostics at Bruce A

    International Nuclear Information System (INIS)

    Bruce A purchased non intrusive check valve diagnostic equipment in 1995 to ensure operability and availability of critical check valves in the Station. Diagnostics can be used to locate and monitor check valve degradation modes. Bruce A initiated a pilot program targeting check valves with flow through them and ones that completed open or close cycles. Approaches to determine how to confirm operability of passive check valves using non intrusive techniques were explored. A sample population of seventy-three check valves was selected to run the pilot program on prior to complete implementation. The pilot program produced some significant results and some inconclusive results. The program revealed a major finding that check valve performance modeling is required to ensure continuous operability of check valves. (author)

  16. Non intrusive check valve diagnostics at Bruce A

    Energy Technology Data Exchange (ETDEWEB)

    Marsch, S.P. [Ontario Hydro, Bruce Nuclear Generating Station A, Tiverton, ON (Canada)

    1997-07-01

    Bruce A purchased non intrusive check valve diagnostic equipment in 1995 to ensure operability and availability of critical check valves in the Station. Diagnostics can be used to locate and monitor check valve degradation modes. Bruce A initiated a pilot program targeting check valves with flow through them and ones that completed open or close cycles. Approaches to determine how to confirm operability of passive check valves using non intrusive techniques were explored. A sample population of seventy-three check valves was selected to run the pilot program on prior to complete implementation. The pilot program produced some significant results and some inconclusive results. The program revealed a major finding that check valve performance modeling is required to ensure continuous operability of check valves. (author)

  17. A study on the condition monitoring of check valve at nuclear power plants using the acoustic emission and a neural network technique

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Min Rae; Lee, Joon Hyun [Busan National Univ., Busan (Korea, Republic of); Kim, Jung Teak [KAERI, Daejeon (Korea, Republic of)

    2005-07-01

    The analysis of Acoustic Emission (AE) signals produced during object leakage is promising for condition monitoring of the components. In this study, an advanced condition monitoring technique based on acoustic emission detection and artificial neural networks was applied to a check valve, one of the components being used extensively in a safety system of a nuclear power plant. AE testing for a check valve under controlled flow loop conditions was performed to detect and evaluate disk movement for valve degradation such as wear and leakage due to foreign object interference in a check valve. It is clearly demonstrated that the evaluation of different types of failure modes such as disk wear and check valve leakage were successful by systematically analyzing the characteristics of various AE parameters. It is also shown that the leak size can be determined with an artificial neural network.

  18. A study on the condition monitoring of check valve at nuclear power plants using the acoustic emission and a neural network technique

    International Nuclear Information System (INIS)

    The analysis of Acoustic Emission (AE) signals produced during object leakage is promising for condition monitoring of the components. In this study, an advanced condition monitoring technique based on acoustic emission detection and artificial neural networks was applied to a check valve, one of the components being used extensively in a safety system of a nuclear power plant. AE testing for a check valve under controlled flow loop conditions was performed to detect and evaluate disk movement for valve degradation such as wear and leakage due to foreign object interference in a check valve. It is clearly demonstrated that the evaluation of different types of failure modes such as disk wear and check valve leakage were successful by systematically analyzing the characteristics of various AE parameters. It is also shown that the leak size can be determined with an artificial neural network

  19. Aging and service wear of check valves used in engineered safety-feature systems of nuclear power plants: Aging assessments and monitoring method evaluations

    International Nuclear Information System (INIS)

    Check valves are used extensively in nuclear power plant safety systems and balance-of-plant systems. The failures of these valves have resulted in significant maintenance efforts and, on occasion, have resulted in water hammer, overpressurization of low-pressure systems, and damage to flow system components. These failures have largely been attributed to severe degradation of internal parts (e.g., hinge pins, hinge arms, discs, and disc nut pins) resulting from instability (flutter) of check valve discs under normal plant operating conditions. Present surveillance requirements for nuclear power plant check valves have been inadequate for timely detection and trending of such degradation because neither the flutter nor the resulting wear can be detected prior to failure. Consequently, the US Nuclear Regulatory Commission has had a continuing strong interest in resolving check valve problems. In support of the Nuclear Plant Aging Research Program, Oak Ridge National Laboratory has carried out an evaluation of several developmental and/or commercially available check valve diagnostic monitoring methods, in particular, those based on measurements of acoustic emission, ultrasonics, and magnetic flux. In each case, the evaluations have been focused on the capability of each method to provide diagnostic information useful in determining check valve aging and service wear effects (degradation), check valve failures, and undesirable operating modes. A description of each monitoring method is provided in this report, including examples of test data acquired under controlled laboratory conditions. In some cases, field test data acquired in situ are also presented. The methods are compared, and suggested areas in need of further development are identified. 6 refs., 36 figs., 7 tabs

  20. Valve monitoring ITI-MOVATS

    International Nuclear Information System (INIS)

    ITI-MOVATS provides a wide range of test devices to monitor the performance of valves: motor operated gate or globe valve, butterfly valve, air operated valve, and check valve. The ITI-MOVATS testing equipment is used in the following three areas: actuator setup/baseline testing, periodic/post-maintenance testing, and differential pressure testing. The parameters typically measured with the MOVATS diagnostic system as well as the devices used to measure them are described. (Z.S.)

  1. Check valve slam analysis in pumping station

    OpenAIRE

    Himr D.; Habán V.; Dokoupil P.

    2016-01-01

    Pumping station supplies water for technological process. The check valve in the station was replaced with a new one. The regular test of black out discovered the high pressure pulsations accompanied with noticeable pipeline movement of discharge pipe. It was caused by late check valve closing, probably, when the back flow reached the highest possible velocity. This statement was supported with analysis of results of pressure measurement near the check valve and with a numerical simulation of...

  2. Check valve slam analysis in pumping station

    Science.gov (United States)

    Himr, D.; Habán, V.; Dokoupil, P.

    2016-03-01

    Pumping station supplies water for technological process. The check valve in the station was replaced with a new one. The regular test of black out discovered the high pressure pulsations accompanied with noticeable pipeline movement of discharge pipe. It was caused by late check valve closing, probably, when the back flow reached the highest possible velocity. This statement was supported with analysis of results of pressure measurement near the check valve and with a numerical simulation of the flow in the pipeline system.

  3. Simple Check Valves for Microfluidic Devices

    Science.gov (United States)

    Willis, Peter A.; Greer, Harold F.; Smith, J. Anthony

    2010-01-01

    A simple design concept for check valves has been adopted for microfluidic devices that consist mostly of (1) deformable fluorocarbon polymer membranes sandwiched between (2) borosilicate float glass wafers into which channels, valve seats, and holes have been etched. The first microfluidic devices in which these check valves are intended to be used are micro-capillary electrophoresis (microCE) devices undergoing development for use on Mars in detecting compounds indicative of life. In this application, it will be necessary to store some liquid samples in reservoirs in the devices for subsequent laboratory analysis, and check valves are needed to prevent cross-contamination of the samples. The simple check-valve design concept is also applicable to other microfluidic devices and to fluidic devices in general. These check valves are simplified microscopic versions of conventional rubber- flap check valves that are parts of numerous industrial and consumer products. These check valves are fabricated, not as separate components, but as integral parts of microfluidic devices. A check valve according to this concept consists of suitably shaped portions of a deformable membrane and the two glass wafers between which the membrane is sandwiched (see figure). The valve flap is formed by making an approximately semicircular cut in the membrane. The flap is centered over a hole in the lower glass wafer, through which hole the liquid in question is intended to flow upward into a wider hole, channel, or reservoir in the upper glass wafer. The radius of the cut exceeds the radius of the hole by an amount large enough to prevent settling of the flap into the hole. As in a conventional rubber-flap check valve, back pressure in the liquid pushes the flap against the valve seat (in this case, the valve seat is the adjacent surface of the lower glass wafer), thereby forming a seal that prevents backflow.

  4. Vertical pump with free floating check valve

    International Nuclear Information System (INIS)

    A vertical pump is described which has a bottom discharge with a free floating check valve disposed in the outlet plenum thereof. The free floating check valve comprises a spherical member with a hemispherical cage-like member attached thereto which is capable of allowing forward or reverse flow under appropriate conditions while preventing reverse flow under inappropriate conditions

  5. Assessment of diagnostic methods for determining degradation of check valves

    International Nuclear Information System (INIS)

    The Oak Ridge National Laboratory (ORNL) has carried out a comprehensive aging assessment of check valves in support of the Nuclear Plant Aging Research (NPAR) program. This paper provides a summary of the ORNL check valve aging assessment with emphasis on the identification, evaluation, and application of check valve monitoring methods and techniques. Several check valve monitoring methods are described and compared. These methods include: acoustic emission monitoring, ultrasonic inspection, magnetic flux signature analysis (MFSA), external magnetics. These diagnostic technologies were shown to be useful in determining check valve condition (e.g., disc position, disc motion, and seat leakage), although none of the methods was by itself, successful in monitoring all three condition indicators. The combination of acoustic emission with either ultrasonics or one of the magnetic technologies, however, yields a monitoring system that succeeds in providing the sensitivity to detect all major check valve operating conditions. Other areas covered in the paper include descriptions of relevant regulatory issues, utility group activities, and interactions ORNL has had with outside organizations for the purpose of disseminating research results

  6. Check valve slam analysis in pumping station

    Directory of Open Access Journals (Sweden)

    Himr D.

    2016-01-01

    Full Text Available Pumping station supplies water for technological process. The check valve in the station was replaced with a new one. The regular test of black out discovered the high pressure pulsations accompanied with noticeable pipeline movement of discharge pipe. It was caused by late check valve closing, probably, when the back flow reached the highest possible velocity. This statement was supported with analysis of results of pressure measurement near the check valve and with a numerical simulation of the flow in the pipeline system.

  7. Glovebox pressure relief and check valve

    Energy Technology Data Exchange (ETDEWEB)

    Blaedel, K.L.

    1986-03-17

    This device is a combined pressure relief valve and check valve providing overpressure protection and preventing back flow into an inert atmosphere enclosure. The pressure relief is embodied by a submerged vent line in a mercury reservior, the releif pressure being a function of the submerged depth. The pressure relief can be vented into an exhaust system and the relieving pressure is only slightly influenced by the varying pressure in the exhaust system. The check valve is embodied by a ball which floats on the mercury column and contacts a seat whenever vacuum exists within the glovebox enclosure. Alternatively, the check valve is embodied by a vertical column of mercury, the maximum back pressure being a function of the height of the column of mercury.

  8. Glovebox pressure relief and check valve

    International Nuclear Information System (INIS)

    This device is a combined pressure relief valve and check valve providing overpressure protection and preventing back flow into an inert atmosphere enclosure. The pressure relief is embodied by a submerged vent line in a mercury reservior, the releif pressure being a function of the submerged depth. The pressure relief can be vented into an exhaust system and the relieving pressure is only slightly influenced by the varying pressure in the exhaust system. The check valve is embodied by a ball which floats on the mercury column and contacts a seat whenever vacuum exists within the glovebox enclosure. Alternatively, the check valve is embodied by a vertical column of mercury, the maximum back pressure being a function of the height of the column of mercury

  9. Pump check valve failures in BWR residual heat removal systems

    International Nuclear Information System (INIS)

    Pump check valve failure mechanisms are often complex and represent a unique challenge, since in many cases, the location of these check valves is critical to proper system operation. Contributing factors identified at the James A. FitzPatrick Nuclear Power Plant included low flow operation of the system as well as excessive flow induced turbulence and cavitation in the system upstream of the check valves. A modification to the system was made to eliminate, or reduce the contribution of the above factors to these valve problems. Several non-standard approaches were taken during the course of modifying the system

  10. Review and analysis of check valve failure data

    Science.gov (United States)

    Todd, M. D.; Casada, D. A.

    Check valve operating problems in recent years have resulted in significant operating transients, increased cost and decreased system availability. There has been, in response, additional attention given to check valves by utilities, as well as the US Nuclear Regulatory Commission and the American Society of Mechanical Engineers Operation and Maintenance Committee. All these organizations have the fundamental goal of ensuring reliable operation of check valves. A key ingredient to an engineering-oriented reliability improvement effort is a thorough understanding of relevant historical experience. Oak Ridge National Laboratory is currently conducting a detailed review of historical failure data available through the Institute of Nuclear Power Operation's Nuclear Plant Reliability Data System. The focus of the review is on check valve failures that have involved significant degradation of the valve internal parts. A variety of parameters are being considered during the review, including size, age, system of service, method of failure discovery, the affected valve parts, attributed causes, and corrective actions.

  11. Neural Network Approach to Automated Condition Classification of a Check Valve by Acoustic Emission Signals

    International Nuclear Information System (INIS)

    This paper presents new techniques under development for monitoring the health and vibration of the active components in nuclear power plants, The purpose of this study is to develop an automated system for condition classification of a check valve one of the components being used extensively in a safety system of a nuclear power plant. Acoustic emission testing for a check valve under controlled flow loop conditions was performed to detect and evaluate disc movement for valve failure such as wear and leakage due to foreign object interference in a check valve, It is clearly demonstrated that the evaluation of different types of failure types such as disc wear and check valve leakage were successful by systematically analyzing the characteristics of various AE parameters, It is also shown that the leak size can be determined with an artificial neural network

  12. Check valve installation in pilot operated relief valve prevents reverse pressurization

    Science.gov (United States)

    Oswalt, L.

    1966-01-01

    Two check valves prevent reverse flow through pilot-operated relief valves of differential area piston design. Title valves control pressure flow to ensure that the piston dome pressure is always at least as great as the main relief valve discharge pressure.

  13. Check all SCHE Supply Purge Check Valves to Prevent Back Flow from SCHE into Helium Supply

    Energy Technology Data Exchange (ETDEWEB)

    MISKA, C.R.

    2000-10-23

    These valves are 1/2-inch check valves used to prevent SCHe backflow into the Helium System if pressure in the Helium System drops below the pressure of the control valve downstream of the SCHe supply bottles. (14 psig in trains A and B and 2 psig in trains C and D).

  14. Check all SCHe Supply Purge Check Valves to Prevent Back Flow from SCHe into Helium Supply

    International Nuclear Information System (INIS)

    These valves are 1/2-inch check valves used to prevent SCHe backflow into the Helium System if pressure in the Helium System drops below the pressure of the control valve downstream of the SCHe supply bottles. (14 psig in trains A and B and 2 psig in trains C and D)

  15. A review of historical check valve failure data

    International Nuclear Information System (INIS)

    Check valve operating problems in recent years have resulted in significant operating transients, increased cost, and decreased system availability. In response, additional attention has been given to check valves by utilities, as well as the US Nuclear Regulatory Commission (NRC) and the American Society of Mechanical Engineers Operation and Maintenance Committee. All these organizations have the fundamental goal of ensuring reliable operation of check valves. A key ingredient of an engineering-oriented reliability improvement effort is a thorough understanding of relevant historical experience. Oak Ridge National Laboratory is currently conducting a detailed review of historical failure data available through the Institute of Nuclear Power Operation's Nuclear Plant Reliability Data System. The focus of the review is on check valve failures that have involved significant degradation of the valve internal parts. A variety of parameters are being considered during the review, including size, age, system of service, method of failure discovery, the affected valve parts, attributed causes, and corrective actions. This work is being carried out under the auspices of the NRC's Nuclear Plant Aging Research program. At this time, the study is approximately 50% complete. All failure records have been reviewed and categorized, and preliminary tabulation and correlation of data is underway. The bulk of the tabulation and correlation portion of the work is expected to be completed by the end of June 1992. A report draft is expected in the fall of 1992

  16. SU8 diaphragm micropump with monolithically integrated cantilever check valves.

    Science.gov (United States)

    Ezkerra, Aitor; Fernández, Luis José; Mayora, Kepa; Ruano-López, Jesús Miguel

    2011-10-01

    This paper presents a SU8 unidirectional diaphragm micropump with embedded out-of-plane cantilever check valves. The device represents a reliable and low-cost solution for integration of microfluidic control in lab-on-a-chip devices. Its planar architecture allows monolithic definition of its components in a single step and potential integration with previously reported PCR, electrophoresis and flow-sensing SU8 microdevices. Pneumatic actuation is applied on a PDMS diaphragm, which is bonded to the SU8 body at wafer level, further enhancing its integration and mass production capabilities. The cantilever check valves move synchronously with the diaphragm, feature fast response (10ms), low dead volume (86nl) and a 94% flow blockage up to 300kPa. The micropump achieves a maximum flow rate of 177 μl min(-1) at 6 Hz and 200 kPa with an effective area of 10 mm(2). The device is reliable, self-priming and tolerant to particles and big bubbles. To the knowledge of the authors, this is the first micropump in SU8 with monolithically integrated cantilever check valves. PMID:21853192

  17. Valve monitoring and evaluation method

    International Nuclear Information System (INIS)

    With the valve monitoring and evaluation method presented here tools are available to optimise the operation of power plants furthermore. With ADAM a self-contained service conception for condition oriented maintenance of valves and actuators is at the operator's disposal. It includes efficient test and diagnosis systems for online and offline use as well as the affiliated engineering procedures and the contribution to the condition evaluating process. Gathered knowledge about the functional behaviour of valves and actuators in detail leads to remarkably increased safety and availability combined with a lucrative reduction of maintenance efforts. (Author)

  18. A magnetically driven PDMS micropump with ball check-valves

    Science.gov (United States)

    Pan, Tingrui; McDonald, Scott J.; Kai, Eleanor M.; Ziaie, Babak

    2005-05-01

    In this paper, we present a low-cost, PDMS-membrane micropump with two one-way ball check-valves for lab-on-a-chip and microfluidic applications. The micropump consists of two functional PDMS layers, one holding the ball check-valves and an actuating chamber, and the other covering the chamber and holding a miniature permanent magnet on top for actuation. An additional PDMS layer is used to cover the top magnet, and thereby encapsulate the entire device. A simple approach was used to assemble a high-performance ball check-valve using a micropipette and heat shrink tubing. The micropump can be driven by an external magnetic force provided by another permanent magnet or an integrated coil. In the first driving scheme, a small dc motor (6 mm in diameter and 15 mm in length) with a neodymium-iron-boron permanent magnet embedded in its shaft was used to actuate the membrane-mounted magnet. This driving method yielded a large pumping rate with very low power consumption. A maximum pumping rate of 774 µL min-1 for deionized water was achieved at the input power of 13 mW, the highest pumping rate reported in the literature for micropumps at such power consumptions. Alternatively, we actuated the micropump with a 10-turn planar coil fabricated on a PC board. This method resulted in a higher pumping rate of 1 mL min-1 for deionized water. Although more integratable and compact, the planar microcoil driving technique has a much higher power consumption.

  19. Regenerable Microbial Check Valve - Life cycle tests results

    Science.gov (United States)

    Atwater, James E.; Wheeler, Richard R., Jr.; Olivadoti, J. T.; Sauer, Richard L.; Flanagan, David T.

    1992-01-01

    Life cycle regeneration testing of the Microbial Check Valve (MCV) that is used on the Shuttle Orbiter to provide microbial control of potable water is currently in progress. Four beds are being challenged with simulated reclaimed waters and repeatedly regenerated. Preliminary results indicate that contaminant systems exhibit unique regeneration periodicities. Cyclic throughput diminishes with increasing cumulative flow. It is considered to be feasible to design a regenerable MCV system which will function without human intervention and with minimal resupply penalty for the 30 year life of the Space Station.

  20. The Structure of Wheel Check Valve Influence on Air Block Phenomenon of Piezoelectric Micro-Pump

    OpenAIRE

    Song Chen; Yong Liu; Yanhu Shen; Jiantao Wang; Zhigang Yang

    2015-01-01

    To improve the stability and reliability of the piezoelectric micro-pump, the cause of air block phenomenon is analyzed on the structure of wheel check valve. During the movement of the bubble in the micro-channel, pressure drop occurs, the main factor which influences the bubble going through is opening height of the wheel check valve. Five groups of wheel check valves with different structures are used to test the wheel check valve opening height and air block probability. The experiment re...

  1. Mitigating check valve slamming and subsequentwater hammer events for PPFS using MOC

    Institute of Scientific and Technical Information of China (English)

    TIAN Wenxi; SU Guanghui; WANG Gaopeng; QIU Suizheng; XIAO Zejun

    2009-01-01

    The method of characteristic (MOC) was adopted to analyze the check valve-induced water hammer behaviors for a Parallel Pumps Feedwater System (PPFS) during the alternate startup process. The motion of check valve disc was simulated using inertial valve model. Transient parameters including the pressure oscillation, local flow velocity and slamming of the check valve disc etc. have been obtained. The results showed that severe slamming between the valve disc and valve seat occurred during the alternate startup of parallel pumps. The induced maximum pressure vibration amplitude is up to 5.0 MPa. The scheme of appending a damping torque to slow down the check valve closing speed was also performed to mitigate of water hammer. It has been numerically approved to be an effective approach.

  2. Development of a butterfly check valve model under natural circulation conditions

    International Nuclear Information System (INIS)

    Highlights: • Bases on Lim’s swing check valve model, a butterfly check valve model was developed. • The method to quantify the friction torque TF in Li’s model was corrected. • The developed model was implemented into the RELAP5 code and verified. - Abstract: A butterfly check valve is widely used to prevent a reverse flow in the pipe lines of a marine nuclear power plant. Under some conditions, the natural circulation conditions in particular, the fluid velocity through the butterfly check valve might become too low to hold the valve disk fully open, thereby the flow resistance of the butterfly check valve varies with the location of the valve disk and as a result the fluid flow is significantly affected by the dynamic motion of the valve disk. Simulation of a pipe line that includes some butterfly check valves, especially under natural circulation conditions, is thus complicated. This paper focuses on the development of a butterfly check valve model to enhance the capability of the thermal–hydraulic system code and the developed model is implemented into the RELAP5 code. Both steady-state calculations and transient calculations were carried out for the primary loop system of a marine nuclear power plant and the calculation results are compared with the experimental data for verification purpose. The simulation results show an agreement with the experimental data

  3. Liquid rocket pressure regulators, relief valves, check valves, burst disks, and explosive valves. [design techniques and practices

    Science.gov (United States)

    1973-01-01

    The development of and operational programs for effective use in design are presented for liquid rocket pressure regulators, relief valves, check valves, burst disks, and explosive valves. A review of the total design problem is presented, and design elements are identified which are involved in successful design. Current technology pertaining to these elements is also described. Design criteria are presented which state what rule or standard must be imposed on each essential design element to assure successful design. These criteria serve as a checklist of rules for a project manager to use in guiding a design or in assessing its adequacy. Recommended practices are included which state how to satisfy each of the criteria.

  4. Application of risk-based methods to inservice testing of check valves

    Energy Technology Data Exchange (ETDEWEB)

    Closky, N.B.; Balkey, K.R.; McAllister, W.J. [and others

    1996-12-01

    Research efforts have been underway in the American Society of Mechanical Engineers (ASME) and industry to define appropriate methods for the application of risk-based technology in the development of inservice testing (IST) programs for pumps and valves in nuclear steam supply systems. This paper discusses a pilot application of these methods to the inservice testing of check valves in the emergency core cooling system of Georgia Power`s Vogtle nuclear power station. The results of the probabilistic safety assessment (PSA) are used to divide the check valves into risk-significant and less-risk-significant groups. This information is reviewed by a plant expert panel along with the consideration of appropriate deterministic insights to finally categorize the check valves into more safety-significant and less safety-significant component groups. All of the more safety-significant check valves are further evaluated in detail using a failure modes and causes analysis (FMCA) to assist in defining effective IST strategies. A template has been designed to evaluate how effective current and emerging tests for check valves are in detecting failures or in finding significant conditions that are precursors to failure for the likely failure causes. This information is then used to design and evaluate appropriate IST strategies that consider both the test method and frequency. A few of the less safety-significant check valves are also evaluated using this process since differences exist in check valve design, function, and operating conditions. Appropriate test strategies are selected for each check valve that has been evaluated based on safety and cost considerations. Test strategies are inferred from this information for the other check valves based on similar check valve conditions. Sensitivity studies are performed using the PSA model to arrive at an overall IST program that maintains or enhances safety at the lowest achievable cost.

  5. Application of risk-based methods to inservice testing of check valves

    International Nuclear Information System (INIS)

    Research efforts have been underway in the American Society of Mechanical Engineers (ASME) and industry to define appropriate methods for the application of risk-based technology in the development of inservice testing (IST) programs for pumps and valves in nuclear steam supply systems. This paper discusses a pilot application of these methods to the inservice testing of check valves in the emergency core cooling system of Georgia Power's Vogtle nuclear power station. The results of the probabilistic safety assessment (PSA) are used to divide the check valves into risk-significant and less-risk-significant groups. This information is reviewed by a plant expert panel along with the consideration of appropriate deterministic insights to finally categorize the check valves into more safety-significant and less safety-significant component groups. All of the more safety-significant check valves are further evaluated in detail using a failure modes and causes analysis (FMCA) to assist in defining effective IST strategies. A template has been designed to evaluate how effective current and emerging tests for check valves are in detecting failures or in finding significant conditions that are precursors to failure for the likely failure causes. This information is then used to design and evaluate appropriate IST strategies that consider both the test method and frequency. A few of the less safety-significant check valves are also evaluated using this process since differences exist in check valve design, function, and operating conditions. Appropriate test strategies are selected for each check valve that has been evaluated based on safety and cost considerations. Test strategies are inferred from this information for the other check valves based on similar check valve conditions. Sensitivity studies are performed using the PSA model to arrive at an overall IST program that maintains or enhances safety at the lowest achievable cost

  6. The Structure of Wheel Check Valve Influence on Air Block Phenomenon of Piezoelectric Micro-Pump

    Directory of Open Access Journals (Sweden)

    Song Chen

    2015-11-01

    Full Text Available To improve the stability and reliability of the piezoelectric micro-pump, the cause of air block phenomenon is analyzed on the structure of wheel check valve. During the movement of the bubble in the micro-channel, pressure drop occurs, the main factor which influences the bubble going through is opening height of the wheel check valve. Five groups of wheel check valves with different structures are used to test the wheel check valve opening height and air block probability. The experiment results show that reducing the wheel check valve thickness or diameter ratio can both increase the wheel check valve opening height, and decrease the air block probability. Through experiment, the optimum combination of the wheel check valve structure is obtained within the samples: as the thickness is 0.02 mm, the diameter ratio is 1.2, the wheel check valve opening height gets 252 µm, and within the given bubble volume, the air block probability is less than 2%.

  7. Effect of check valve on consequences of coolant pump rotor seizure accident for EPR reactor

    International Nuclear Information System (INIS)

    Counter current flow phenomenon would appear during reactor coolant pump rotor seizure accident. Present work analyzes the coolant pump rotor seizure accident for European Pressurized Reactor (EPR). The accident safety analysis results of model with check valve and with out check valve are compared. It can be found that the check valve can increase the core inlet flow rate of model about 4%. The increasing of coolant flow rate is beneficial to the reactor core cooling. Check valve can increase the minimum departure from nucleate boiling ratio (DNBR), reduce the departure from nucleate boiling (DNB) fraction and the fuel rod cladding temperature about 14℃ during coolant pump rotor seizure accident. The analyses results show that the model with check valve can maintain the integrity of nuclear fuel rod effectively during reactor coolant pump rotor seizure accident. (authors)

  8. Transient analysis for a system with a tilted disc check valve

    International Nuclear Information System (INIS)

    Check valves are used to prevent reverse flow conditions in a variety of systems in nuclear power plants. When a check valve is closed by a reverse flow, the transient load can jeopardize the structural integrity on the piping system and its supports. It may also damage intended function of the in-line components even though the severity of the load differs and depends strongly on types of the check valves. To incorporate the transient load in the piping system, it is very important to properly predict the system response to transients such as a check valve closure accompanied by pump trip and to evaluate the system transient. The one-dimensional transient simulation codes such as the RELAP5/MOD3.3 and TRACE were used. There has not been a single model that integrates the two codes to handle the behavior of a tilted disc check valve, which is designed to mitigate check valve slams by shorting the travel of the disc. In this paper a model is presented to predict the dynamic motion of a tilted disc check valve in the transient simulation using the RELAP5/MOD3.3 code and the model is incorporated in a system transient analysis using control variables of the code. In addition, transient analysis for Essential Service Water (ESW) system is performed using the proposed model and the associated load is evaluated for the system. (author)

  9. Failure investigation of type 410 stainless steel retaining block studs of swing check valves in pressurized water reactors

    International Nuclear Information System (INIS)

    Retaining block studs in swing check valves employed in Emergency Core Cooling System of pressurized water reactors have been the subject of cracking during the past few years. The studs are made from ASTM A-193 Gr. 6 type 410 stainless steel material. USNRC issued an information notice on the issue encouraging utilities to take appropriate actions to monitor/replace the studs so as to prevent a potential dislodging of the valve retaining blocks that can cause flow blockage in the valves. The current paper summarizes the results of a metallurgical investigation aimed at establishing the mechanism and cause(s) of the valve stud cracking. Potential candidate replacement materials to remedy the cracking issue are also considered

  10. Numerical simulation of local flow characteristics of contra-push check valve

    International Nuclear Information System (INIS)

    When the working condition of primary pump of pressurized water reactor (PWR) changes, water hammer phenomena appear in the loop to some extent. Severe water hammer not only would bring incident of instant over pressure and endanger the pressure boundary, but also yield the check valve failure. The contra-push check valve (CPCV) is a new kind of check valve. Its new structural design of river diversion can well reduce the water hammer phenomena, thereby enhancing the operational safety of nuclear power plant. The flow field and pressure distribution of the impact tube laryngeal and the connected cavity during the valve closing process were veritably simulated with computational fluid dynamics (CFD) simulation software FLUENT. The dynamic grid and UDF (user-defined function) technology were used in simulation. The results show that although the changes of the geometry will lead to the local flow velocity higher than that of the other part in the closing process, but the impact on the valve closing stability is very small. In addition, through the analysis of the flow field, it is found that the valve closing process can be divided into three stages, each of which shows its own independent characteristics. The study of this paper has provided a basis for future improvement of the valve structure and reliability analysis. (authors)

  11. Check valve slam caused by air intrusion in emergency cooling water system

    International Nuclear Information System (INIS)

    Waterhammer pressures were experienced during periodic starting of Residual Heat Removal (RHR) pumps at a nuclear plant. Prior to an analytical investigation careful analysis performed by plant engineers indicated that the spring effect of entrapped air in a heat exchanger resulted in water hammer due to check valve slam following flow reversal. In order to determine in more detail the values of pertinent parameters controlling this water hammer a hydraulic transient analysis was performed of the RHR piping system, including essential elements such as the pump, check valve, and heat exchanger. Using characteristic torque and pressure loss curves the motion of the check valve was determined. By comparing output of the water hammer analysis with site recordings of pump discharge pressure the computer model was calibrated, allowing for a realistic estimate of the quantity of entrapped air in the heat exchanger. (author)

  12. A self-priming, high performance, check valve diaphragm micropump made from SOI wafers

    Science.gov (United States)

    Kang, Jianke; Mantese, Joseph V.; Auner, Gregory W.

    2008-12-01

    In this paper, we describe a self-priming high performance piezoelectrically actuated check valve diaphragm micropump. The micropump was fabricated from three wafers: two silicon-on-insulator (SOI) wafers and one silicon wafer. A process named 'SOI/SOI wafer bonding and etching back followed by a second wafer bonding' was developed in order to make the core components of this device which included an inlet check valve, an outlet check valve, a diaphragm and a chamber. The movable structures of this device, i.e. the check valves and the diaphragm, were fabricated from the device layers of the two bonded SOI wafers. Taking advantages of SOI wafer technology and etch-stop layers, the vertical parameters of the movable structures were precisely controlled in fabrication. The micropump was self-priming without any pre-filling process. The pumping rate of the micropump was linearly adjustable from 0 to 650l µm min-1 by adjusting frequency. The maximum pumping rate was 860 µl min-1 and the maximum pumping pressure was approximately 10.5 psi. The power consumption of the device was less than 1.2 mW.

  13. A self-priming, high performance, check valve diaphragm micropump made from SOI wafers

    International Nuclear Information System (INIS)

    In this paper, we describe a self-priming high performance piezoelectrically actuated check valve diaphragm micropump. The micropump was fabricated from three wafers: two silicon-on-insulator (SOI) wafers and one silicon wafer. A process named 'SOI/SOI wafer bonding and etching back followed by a second wafer bonding' was developed in order to make the core components of this device which included an inlet check valve, an outlet check valve, a diaphragm and a chamber. The movable structures of this device, i.e. the check valves and the diaphragm, were fabricated from the device layers of the two bonded SOI wafers. Taking advantages of SOI wafer technology and etch-stop layers, the vertical parameters of the movable structures were precisely controlled in fabrication. The micropump was self-priming without any pre-filling process. The pumping rate of the micropump was linearly adjustable from 0 to 650l µm min−1 by adjusting frequency. The maximum pumping rate was 860 µl min−1 and the maximum pumping pressure was approximately 10.5 psi. The power consumption of the device was less than 1.2 mW

  14. Modelling of coupled self-actuating safety, relief and damped check valve systems with the codes TRAC-PF1 and ROLAST

    International Nuclear Information System (INIS)

    Numerical valve models for simulation of selfactuating safety valves and damped check valves are introduced for the computer programs TRAC-PF1 and ROLAST. As examples of application post-test calculations and stability analysis are given. (orig.)

  15. Monitoring Blood Sugar: The Importance of Checking Blood Sugar Levels

    Science.gov (United States)

    ... 5 Things to Know About Zika & Pregnancy Monitoring Blood Sugar KidsHealth > For Parents > Monitoring Blood Sugar Print ... Other Tests Record Keeping The Importance of Checking Blood Sugar Levels Besides helping to keep blood sugar ...

  16. Development of a check valve for two-stage pellet injectors

    International Nuclear Information System (INIS)

    The two-stage light gas gun is presently the most suitable method for injecting solid deuterium pellets at velocities in excess of 2000 m/s. However, the use of this technique in plasma machines presents some drawbacks: (1) the relatively large mass of propellant, which is of the same order of the pellet mass; (2) the shape of the pressure pulse, which does not provide an optimum acceleration, unless the pellet is forced in the barrel, providing a sufficient breakout pressure. These problems can be solved completely or in part, by interposing between the pump tube and the barrel a check valve with a suitable opening pressure. In this work a check valve developed at CNPM is described and experimental results are reported

  17. Dual Check Valve and Method of Controlling Flow Through the Same

    Science.gov (United States)

    Corallo, Roger (Inventor)

    2016-01-01

    A dual check valve includes, a housing having a cavity fluidically connecting three ports, a movable member movably engaged within the cavity from at least a first position occluding a first port of the three ports, a second position occluding a second port of the three ports, and a third position allowing flow between both the first port, the second port and a third port of the three ports.

  18. Polymeric check valve with an elevated pedestal for precise cracking pressure in a glaucoma drainage device.

    Science.gov (United States)

    Park, Chang-Ju; Yang, Dong-Seong; Cha, Jung-Joon; Lee, Jong-Hyun

    2016-02-01

    This paper presents the design, fabrication, and characterization of a polymeric micro check valve for a glaucoma drainage device (GDD) featuring the precise regulation of intraocular pressure (IOP) and effective aqueous humor turnover (AHT). The pedestal, slightly elevated by selective coating of a parylene C film, induces pre-stress in the thin valve membrane, which enhances the predictability of the cracking pressure of the GDD. The proposed GDD comprises a cannula and a normally closed polymeric micro check valve, which are made of PDMS, a biocompatible polymer, with three layers: top (cover), intermediate (thin valve membrane), and bottom (base plate). A feedback channel, located between the top and intermediate layers, prevents reverse flow by feeding the pressure of the outlet channel back to the thin valve membrane. To achieve a precise cracking pressure and sufficient drainage of humor for humans, the thicknesses of the valve membrane and parylene C film are designed to be 58 μm and 1 μm, respectively, which are confirmed using a COMSOL simulation. The experimental results show that the cracking pressure of the fabricated GDD lies within the range of normal IOP (1.33-2.67 kPa). The forward flow rate (drainage rate), 4.3 ± 0.9 μL/min at 2.5 kPa, is adequate to accommodate the rate of AHT in a normal human eye (2.4 ± 0.6 μL/min). The reverse flow was not observed when a hydrostatic pressure of up to 4 kPa was applied to the outlet and the feedback channel. PMID:26864969

  19. Bubble dynamics in a micro-channel with a virtual check valve

    Science.gov (United States)

    Chen, Rou; Zhu, Likun; Yu, Huidan (Whitney)

    2015-11-01

    Bubble dynamics plays a critical role in the design of a self-circulation and self-regulation gas generator with little or zero parasitic power consumption (Zhu et al, Microfluidics and Nanofluidics, 2011). We numerically study bubble dynamics in the micro-channel with a virtual check valve using lattice Boltzmann method. The lattice Boltzmann model has been validated through several static cases with a bubble sitting inside a liquid and on a solid surface with a triple contact among bubble, liquid, and solid. In this work, we simulate bubble transport driven via unbalanced capillary forces. Focus will be on the bubble merging phenomena between the moving bubble and a static bubble prior siting downstream in the channel with same and different sizes. By varying the size of the check valve, we study the effects of channel ratio between the check valve and channel on the dynamics of bubble-driven liquid circulation and seek for an optimal channel ratio to support experimental design. This research is supported by NSF Collaborative Research (1264739).

  20. Valve packing leakage monitoring device

    International Nuclear Information System (INIS)

    A device for monitoring leakage of fluid across a seal in a component connected to a pressurized fluid system including a housing having a chamber with an inlet for receiving fluid leaking across the seal and an outlet. A positioning means is connected to an orifice plug so as to move the plug for permitting the fluid to be discharged through the orifice at the same rate at which it enters the first chamber and means for detecting the movement of the plug is provided to produce and output signal corresponding to the distance moved by the plug and thereby indicate flow rate. The positioning means compromise a piston attached to the plug by a hollow tube and springs, which at low flow rates locate the piston. When flow increases sufficiently pressure increases and urges the piston upwards. A magnetic portion of tube actuates a succession of proximity switches to indicate flow rate. (author)

  1. Valve studies: Hydrogen fluoride monitoring of UF6 cylinder valves

    International Nuclear Information System (INIS)

    Uranium hexafluoride (UF6) cylinder valves have, like the cylinders, been in use and/or storage for periods ranging from 15 to 44 years. Visual inspection of the cylinders has shown that the extent of corrosion and the overall cylinder condition varies widely throughout the storage yards. One area of concern is the integrity of the cylinder valves. Visual inspection has found deposits which have been identified as radioactive material on or near the valves. These deposits suggest leakage of UF6 and may indicate valve degradation; however, these deposits may simply be residual material from cylinder filling operations

  2. 3D Printed Unibody Lab-on-a-Chip: Features Survey and Check-Valves Integration

    Directory of Open Access Journals (Sweden)

    Germán Comina

    2015-04-01

    Full Text Available The unibody lab-on-a-chip (ULOC concept entails a fast and affordable micro-prototyping system built around a single monolithic 3D printed element (unibody. A consumer-grade stereo lithography (SL 3D printer can configure ULOCs with different forms of sample delivery, transport, handling and readout, while minimizing material costs and fabrication time. ULOC centralizes all complex fabrication procedures and replaces the need for clean room resources, delivering prototypes for less than 1 US$, which can be printed in 10 min and ready for testing in less than 30 min. Recent examples of ULOC integration of transport, chemical sensing for optical readout and flow mixing capabilities are discussed, as well as the integration of the first check-valves for ULOC devices. ULOC valves are strictly unidirectional up to 100 psi, show an exponential forward flow behavior up to 70 psi and can be entirely fabricated with the ULOC approach.

  3. A characterization of check valve degradation and failure experience in the nuclear power industry: 1991 Failures, Volume 2

    International Nuclear Information System (INIS)

    Review and characterization of check valve failures taken from the Institute of Nuclear Power Operation's Nuclear Plant Reliability Data System was performed in accordance with part two of a three-phase project sponsored by the US Nuclear Regulatory Commission. The analysis was performed for check valve failures occurring in 1991 and is intended to update the previous analysis performed for the time period 1984--1990. To maintain consistency and for ease of the 1991 analysis presents the same parameters and cross-correlations in essentially the same format as the 1984--1990 study. Additional data was obtained for the 1991 analysis, including information related to specific check valve type. This information is presented in a separate section of the report

  4. Method and apparatus for monitoring motor operated valve motor output torque and power at valve seating

    Science.gov (United States)

    Casada, Donald A.

    1996-01-01

    A method and apparatus are provided for monitoring a motor operated valve during the brief period when the valve seats and the torque switch trips to deenergize the valve motor. The method uses voltage measurements on the load side of a deenergizing switch that opens to deenergize the motor to determine, among other things, final motor rotational speed and the decelerating torque at motor deenergization.

  5. Resin pumps and check valves. Resin pumps with resistance to seawater

    International Nuclear Information System (INIS)

    Seawater is utilized at thermal/nuclear power plants, chemical plants, and various other fields. In most of all the pumps used there, corrosion protection against seawater and maintenance management have become important issues. Seawater pumps are typically made of stainless steel-based materials, while plastic pumps having excellent corrosion resistance are used in a very limited range competing with many problems. This paper takes up PENTAM, a plastic made by the molding method called ZEON-RIM system developed by ZEON Corp., and introduces its characteristics. As the pump products made of PENTAM resin, it introduces the pumps and unit products, such as centrifugal pump FRS type, self-priming pump FPSQ type, mixed-flow pump FPSZ type, and hammer soft check valve CVRSP type. (A.O.)

  6. Thermal-hydraulic analysis for changing feedwater check valve leakage rate testing methodology

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, R.; Harrell, J.

    1996-12-01

    The current design and testing requirements for the feedwater check valves (FWCVs) at the Grand Gulf Nuclear Station are established from original licensing requirements that necessitate extremely restrictive air testing with tight allowable leakage limits. As a direct result of these requirements, the original high endurance hard seats in the FWCVs were modified with elastomeric seals to provide a sealing surface capable of meeting the stringent air leakage limits. However, due to the relatively short functional life of the elastomeric seals compared to the hard seats, the overall reliability of the sealing function actually decreased. This degraded performance was exhibited by frequent seal failures and subsequent valve repairs. The original requirements were based on limited analysis and the belief that all of the high energy feedwater vaporized during the LOCA blowdown. These phenomena would have resulted in completely voided feedwater lines and thus a steam environment within the feedwater leak pathway. To challenge these criteria, a comprehensive design basis accident analysis was developed using the RELAP5/MOD3.1 thermal-hydraulic code. Realistic assumptions were used to more accurately model the post-accident fluid conditions within the feedwater system. The results of this analysis demonstrated that no leak path exists through the feedwater lines during the reactor blowdown phase and that sufficient subcooled water remains in various portions of the feedwater piping to form liquid water loop seals that effectively isolate this leak path. These results provided the bases for changing the leak testing requirements of the FWCVs from air to water. The analysis results also established more accurate allowable leakage limits, determined the real effective margins associated with the FWCV safety functions, and led to design changes that improved the overall functional performance of the valves.

  7. Thermal-hydraulic analysis for changing feedwater check valve leakage rate testing methodology

    International Nuclear Information System (INIS)

    The current design and testing requirements for the feedwater check valves (FWCVs) at the Grand Gulf Nuclear Station are established from original licensing requirements that necessitate extremely restrictive air testing with tight allowable leakage limits. As a direct result of these requirements, the original high endurance hard seats in the FWCVs were modified with elastomeric seals to provide a sealing surface capable of meeting the stringent air leakage limits. However, due to the relatively short functional life of the elastomeric seals compared to the hard seats, the overall reliability of the sealing function actually decreased. This degraded performance was exhibited by frequent seal failures and subsequent valve repairs. The original requirements were based on limited analysis and the belief that all of the high energy feedwater vaporized during the LOCA blowdown. These phenomena would have resulted in completely voided feedwater lines and thus a steam environment within the feedwater leak pathway. To challenge these criteria, a comprehensive design basis accident analysis was developed using the RELAP5/MOD3.1 thermal-hydraulic code. Realistic assumptions were used to more accurately model the post-accident fluid conditions within the feedwater system. The results of this analysis demonstrated that no leak path exists through the feedwater lines during the reactor blowdown phase and that sufficient subcooled water remains in various portions of the feedwater piping to form liquid water loop seals that effectively isolate this leak path. These results provided the bases for changing the leak testing requirements of the FWCVs from air to water. The analysis results also established more accurate allowable leakage limits, determined the real effective margins associated with the FWCV safety functions, and led to design changes that improved the overall functional performance of the valves

  8. Concept for processing of silicon check valves by proton beam micromachining

    Energy Technology Data Exchange (ETDEWEB)

    Duecso, Cs. [Research Institute for Technical Physics and Materials Science, H-1525 Budapest, P.O. Box 49 (Hungary); Rajta, I. [Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4001 Debrecen, P.O. Box 51 (Hungary)]. E-mail: rajta@atomki.hu; Fuerjes, P. [Research Institute for Technical Physics and Materials Science, H-1525 Budapest, P.O. Box 49 (Hungary); Baradacs, E. [Department of Environmental Physics, University of Debrecen, H-4026 Debrecen, Poroszlay u. 6 (Hungary)

    2007-07-15

    In this work, we present alternative methods for the formation of a simple a check valve for microfluidic applications. In two different approaches we exploited the characteristic features of the proton beam micromachining (PBM) technique and the selective formation and dissolution of porous Si around the implantation damaged areas. In the first case, we implanted 10 {mu}m thick cantilever-type membrane of the valve normally to the crystal surface and at 30-60{sup o} to the sidewalls of the flow channel, which were also implanted at the same irradiation. During the porous Si formation we developed the sample 6-8 {mu}m deeper than the implanting ion range damaged the crystal. Due to the isotropic nature of the porous Si etching, the thick sidewall blocks are still connected to the crystal while the thin membranes detached from the bottom, and they are only connected to one of the sidewalls. The other construction utilized the goniometer facility mounted on the microbeam chamber. We implanted the samples at 43{sup o} tilt, and developed the samples not as deep as the ion range. This way both the sidewalls and the membranes are attached to the bottom of the sample.

  9. Alternative method for full flow stroke testing of safety injection tank check valves at Fort Calhoun Nuclear Station

    International Nuclear Information System (INIS)

    This paper presents the evolution that led to the use of a reduced pressure safety injection tank (SIT) dump as the preferred test method for full-stroke testing the SIT check valves at Fort Calhoun Station. This discussion includes the following: (1) An interpretation of the Code requirements for full-stroke testing of check valves, (2) problems encountered with various test methods, (3) the analysis technique used to relate the reduced-pressure flow test results to safety analysis flow requirements, (4) a description of the test method and results to date, and (5) summary of resource expenditures while evaluating the test methods. Fort Calhoun Station found that a reduced-pressure SIT dump was the most cost-effective method of SIT chock valve testing that would yield credible test results

  10. Annex III. Implementation of condition monitoring techniques to improve valve reliability and performance

    International Nuclear Information System (INIS)

    Innovations in technology have provided for the development and use of sophisticated diagnostic systems for monitoring plant equipment such as motor-operated valves, pneumatic control valves, check valves and motors. This capability has in a sense allowed us to revise our plant maintenance philosophy concerning valves and motors in nuclear power plants from time-based maintenance practices to condition based maintenance (CBM). In the establishment of a predictive maintenance philosophy, the equipment's operability, working environment and risk significance are taken into consideration in determining the frequency of testing as well as the need for maintenance. The activities of several international nuclear organizations have kept pace with the technology and have initiated process improvements necessary to maximize the technical and economic benefits of condition based maintenance. This paper discusses adoption of valve and motor condition monitoring in the nuclear power industry, relevant documentation and research in this field, and recent efforts to combine risk assessment with condition monitoring strategies to achieve the highest level of reliability and safety without significantly affecting operation and maintenance cost. (author)

  11. ICDE project report: collection and analysis of common-cause failure of check valves

    International Nuclear Information System (INIS)

    This report documents a study performed on the set of Common Cause Failure (CCF) events of Check Valves (CVs). The events studied here were derived from the International CCF Data Exchange (ICDE) database. Organizations from Canada, Finland, France, Germany, Netherlands, Sweden, Switzerland and the United States contributed with data to this data exchange. This study examines 94 CCF events of CVs reported in the ICDE database by tabulating the data and observing trends. The database contains general information about event attributes like root cause, coupling factor, detection method and corrective action taken. As part of this study, most of these events were reviewed in more detail and characterized by failure cause and failure symptom categories. The study itself begins with an overview of the entire data set in chapter 5. Charts are provided for each of the above-mentioned event attributes. This chapter forms the baseline for chapter 6. The intention of chapter 6 is to give the reader a deeper qualitative insight in the database content beyond that obtained from using the event coding only. Chapter 7 contains the summary of the study results and the conclusions derived from. Approximately 8% of all ICDE events of CVs were complete CCFs (all redundant components had failed). The number of partial CCF events (at least two of the redundant components failed) accounted for 24%. In the remaining 68% of the ICDE events, less than two components had failed completely, and the other components of the observed group only suffered from small defects, incipient degradation or were not affected at all. However, it was found that for more than 75% of the ICDE events the causal factors had a high probability to be shared by all the redundant components. 88 of the 94 reported ICDE events were reviewed in some more detail in Section 6 of this report with respect to failure causes, failure symptoms and failure mechanism. All events classified with a low 'shared cause factor

  12. Internal flow Patterns of the Horizontal Heat Mode Closed-Loop Oscillating Heat Pipe with Check Valves (HHMCLOHP/CV

    Directory of Open Access Journals (Sweden)

    S. Sangiamsuk

    2013-01-01

    Full Text Available This research was to study the internal flow patterns on heat transfer rates of the Horizontal Heat Mode Closed Loop Oscillating Heat Pipe with Check Valves (HHMCLOHP/CV. The HHMCLOHP/CV was made from a Pyrex glass capillary tube with a 2.4 mm inside diameter. There were 10 meandering turns with 2 check valves. Ethanol and a silver nano-ethanol mixture were used as working fluid. Experimental results found that if working fluid varies from ethanol to a silver nano-ethanol mixture and the evaporator temperature increases the main flow patterns were Slug flow + Annular flow. The main regime of each flow pattern can be determined from the flow pattern map.

  13. Inspection systems for valves monitoring at EDF

    International Nuclear Information System (INIS)

    Electricite de France (EDF) makes increasing use of valve inspection systems to guarantee safety in its pressurized water reactor plants, improve plant availability and facilitate condition-based maintenance. A portable system known as SAMIR has been developed for inspection of motor-operated valves, and is now used on EDF's 900-MW sites. For its 1300-MW units, EDF has chosen a more complete system which enables measuring thrust on the valve stem during a maneuver, using a sensor mounted on the yoke. To detect internal vale leaks, an on-site assessment has demonstrated the economic benefits of acoustic emission techniques. EDF has equipped its sites with analog leak detection systems which may soon be replaced by a digital model now being developed. (authors)

  14. Acoustic monitoring of BWR main steam safety relief valves

    International Nuclear Information System (INIS)

    Main steam safety relief valves (SRVs) are important equipment in boiling water reactor plants, so monitoring of leakage and valve opening of SRVs is also important. To detect leakage and valve opening, thermocouples are installed on exhaust pipes and limit switches or position sensors on valve stems. The acoustic detection technique with AE sensors and accelerometers is adopted not only to increase the accuracy and response speed of leak detection, but also to estimate leak rate and to detect valve opening. The acoustic leak detection technique was found effective by the mock-up experiment in which an actual SRV and steam under the same condition as the actual use were used to measure the signals from AE sensors and accelerometers attached to the SRV with artificial cuttings on its thermal disk. The acoustic monitoring tests of SRVs have been carried out at a nuclear power plant to prove the acoustic leak detection technique to be effective. The results of the acoustic monitoring tests at the plant are discussed. As a result of the on-site test, the acoustic leak monitoring system was found effective in the plant

  15. High-Temperature Engineering Test Reactor door valve monitor system

    International Nuclear Information System (INIS)

    This manual describes the detector design features, performance, and operating characteristics of the High-Temperature Engineering Test Reactor (HTTR) Door Valve Monitor System spent-fuel monitor. The HTTR Door Valve Monitor System (HDVM) is installed in the HTTR door valve to provide unattended monitoring data for the transfer of spent fuel through the door valve on the top of the reactor. The system includes a pair of detectors to provide direction of travel and redundancy. The fission product gamma rays are measured using ion chambers (ICs) and the curium neutrons are measured using shielded 3He detectors. There are two ICs and one 3He tube inside each detector package. Gamma-ray and neutron detector (GRAND) electronics supply power to the ICs and 3He tubes, and the data are collected in the GRAND and the Field Works computer. The system is designed to operate unattended with data pickup by the inspectors on a 90-day period. This manual gives the performance and calibration procedures

  16. Acoustic monitoring of safety/relief valves for leak detection

    International Nuclear Information System (INIS)

    The results presented here indicate that there is a high probability of confidentially detecting pilot stage leakage in safety/relief valves through the use of acoustic monitoring, especially in the frequency range 30-60 kHz. This should be particularly true if the sensors and signal processing equipment are designed for sensitivity to this range, and if routine or continuous monitoring is performed so that trends can be recognized

  17. Effect of Evaporator Lengths and Ratio of Check Valves to Number of Turns on Internal Flow Patterns of a Closed-Loop Oscillating Heat-Pipe With Check Valves

    Directory of Open Access Journals (Sweden)

    S. Rittidech

    2008-01-01

    Full Text Available A visualization study of the internal flow patterns of a closed–loop oscillating heat-pipe with check valves (CLOHP/CV at normal operating condition for several evaporator lengths (Le, and ratio of check valves to number of turns (Rcv has been conducted. This article describes the effects of varying Le, and Rcv on flow patterns. The CLOHP/CV used a Pyrex glass tube with inside diameter of 2.4 mm. The evaporator length of 50 and 150 mm. (the lengths of evaporator, adiabatic and condenser were equal were employed with 10 turns, with Rcv of 0.2 and 1. R123 was used as the working fluid with filling ratio of 50% of internal volume of tube. It was found that the internal flow patterns could be classified according to the Le and Rcv as follows: At the high heat source when the Le decreases the main flow changes from the bubble flow with slug flow to disperse bubble flow. The Rcv decreases the main flow changes from the disperse bubble flow with bubble flow to disperse bubble When the velocity of slug increases, the length of vapor bubbles rapidly decreases and the heat flux rapidly increases.

  18. Model based feasibility study on bidirectional check valves in wave energy converters

    DEFF Research Database (Denmark)

    Hansen, Anders Hedegaard; Pedersen, Henrik C.; Andersen, Torben Ole

    2014-01-01

    valves in wave energy converters to improve the system efficiency. A single float arm of the Wavestar wave energy converter is modelled including the power take-off (PTO) system. The primary stage of the utilised PTO-system is a discrete fluid power force system consisting of a multi-chamber cylinder and...

  19. Phi29 Connector-DNA Interactions Govern DNA Crunching and Rotation, Supporting the Check-Valve Model.

    Science.gov (United States)

    Kumar, Rajendra; Grubmüller, Helmut

    2016-01-19

    During replication of the ϕ29 bacteriophage inside a bacterial host cell, a DNA packaging motor transports the viral DNA into the procapsid against a pressure difference of up to 40 ± 20 atm. Several models have been proposed for the underlying molecular mechanism. Here we have used molecular dynamics simulations to examine the role of the connector part of the motor, and specifically the one-way revolution and the push-roll model. We have focused at the structure and intermolecular interactions between the DNA and the connector, for which a near-complete structure is available. The connector is found to induce considerable DNA deformations with respect to its canonical B-form. We further assessed by force-probe simulations to which extent the connector is able to prevent DNA leakage and found that the connector can act as a partial one-way valve by a check-valve mechanism via its mobile loops. Analysis of the geometry, flexibility, and energetics of channel lysine residues suggested that this arrangement of residues is incompatible with the observed DNA packaging step-size of ∼2.5 bp, such that the step-size is probably determined by the other components of the motor. Previously proposed DNA revolution and rolling motions inside the connector channel are both found implausible due to structural entanglement between the DNA and connector loops that have not been resolved in the crystal structure. Rather, in the simulations, the connector facilitates minor DNA rotation during the packaging process compatible with recent optical-tweezers experiments. Combined with the available experimental data, our simulation results suggest that the connector acts as a check-valve that prevents DNA leakage and induces DNA compression and rotation during DNA packaging. PMID:26789768

  20. Selection of Antiagers for Check Valve Rubber%单向阀胶防老剂的选取

    Institute of Scientific and Technical Information of China (English)

    陈丽飞; 金耀程; 韩雪

    2016-01-01

    In order to solve the odor, the antiager in existing check valve rubber formula was replaced, and the tensile strength, elongation at break, hardness(Shaw A), permanent deformation, the hot air aging, flexible crack, ozone aging were measured. Through data analysis, suitable antiager was selected.%通过替换现有成熟单向阀胶料配方中防老剂的品种以解决气味问题,并进行拉伸强度、拉断伸长率、硬度(邵氏 A)、永久变形、热空气老化、屈挠龟裂、臭氧老化测定,通过数据对比分析选取符合潜水帽单向阀性能要求和使用要求的防老剂。

  1. Preservation Health Check: Monitoring Threats to Digital Repository Content

    Science.gov (United States)

    Kool, Wouter; van der Werf, Titia; Lavoie, Brian

    2014-01-01

    The Preservation Health Check (PHC) project, undertaken as a joint effort by Open Planets Foundation (OPF) and OCLC Research, aims to evaluate the usefulness of the preservation metadata created and maintained by operational repositories for assessing basic preservation properties. The PHC project seeks to develop an implementable logic to support…

  2. 轴流式止回阀动态特性%Dynamic characteristics of axial flow check valve

    Institute of Scientific and Technical Information of China (English)

    杨国来; 伍国果; 刘小雄; 曹文斌; 许敏影

    2013-01-01

    The unsteady fluid flow caused from the moving disc in an axial flow check valve was numerically simulated by means of the computational methods and flow physical models available in CFD code-Fluent.The disc regularly instantaneous movement was realized by the dynamic mesh technique and UDF (user defined function) in Fluent.The transient pressure and velocity were obtained during a period of the disc being closed by means of unstructured mesh,the standard k - e turbulence model.Those transient characteristic curves have been measured experimentally as well,and exhibit good a-greement with the predicted ones,suggesting the numerical simulation method is reliable.Moreover,such dynamic characteristic curves were calculated in the valves in various nominal diameters and external forces and their influences have been identified.Those results will play a critical role in investigation into water hammer effect in the axial flow check valve,and might be useful for check valve design in engineering projects.%基于Fluent软件提供的计算方法和物理模型,利用动网格及用户自定义函数技术对轴流式止回阀的阀瓣运动过程进行动态数值模拟.通过动网格较好地解决了因阀瓣运动而导致的计算区域瞬时变化的问题.利用CFD软件Fluent,采用非结构化网格,标准k-ε湍流模型,模拟了阀瓣关闭的动态过程中,止回阀内压力场和速度场的瞬态变化过程,计算出动态特性曲线,并进行了相应的试验验证.结果表明:运用动网格技术能较好地模拟止回阀内部压力和速度的动态变化,试验结果与数值计算结果趋于一致,验证了数值模拟的可靠性.通过数值模拟不同公称直径和外力下止回阀内的压力场和速度场的瞬态变化,计算出对应的动态特性曲线,并总结了止回阀的公称直径和外力对其动态特性的影响结果,对工程设计与管理具有指导作用.

  3. Specifying Safety Monitors for Autonomous Systems using Model-checking

    OpenAIRE

    Machin, Mathilde; Dufossé, Fanny; Blanquart, Jean-Paul; Guiochet, Jérémie; Powell, David; Waeselynck, Hélène

    2014-01-01

    International audience Autonomous systems operating in the vicinity of humans are critical in that they potentially harm humans. As the complexity of autonomous system software makes the zero-fault objective hardly at- tainable, we adopt a fault-tolerance approach. We consider a separate safety channel, called a monitor, that is able to partially observe the sys- tem and to trigger safety-ensuring actuations. A systematic process for specifying a safety monitor is presented. Hazards are fo...

  4. Modeling Criterion Shifts and Target Checking in Prospective Memory Monitoring

    Science.gov (United States)

    Horn, Sebastian S.; Bayen, Ute J.

    2015-01-01

    Event-based prospective memory (PM) involves remembering to perform intended actions after a delay. An important theoretical issue is whether and how people monitor the environment to execute an intended action when a target event occurs. Performing a PM task often increases the latencies in ongoing tasks. However, little is known about the…

  5. System of monitoring and diagnosis of motor-operated valves using fuzzy logic

    International Nuclear Information System (INIS)

    The issue about of reliability of components, more specifically motor-operated valves related to safety systems, has became one of the most important factors to be investigated in nuclear power plants. This work has presented a direct application of fuzzy logic in monitoring and diagnosis systems of motor-operated valves used in nuclear power plants safety systems, based on motor signature power analysis during the operation of opening and closure of valve

  6. On-line valve monitoring at the Ormen Lange gas plant

    International Nuclear Information System (INIS)

    The purpose of this presentation is to discuss replacing time and labor intensive nuclear outage activities with on line condition monitoring solutions, primarily the periodic verification of MOV functionality discussed in USNRC Generic Letter 96.05. This regulation requires that MOV age related performance degradations are properly identified and accounted for, causing utilities to have to retest valves periodically for the duration of the plants operating license. AECL designed CANDU reactors have a world class performance and safety record, with typical average annual capacity factors of 90%. The CANDU reactor design has the ability to refuel on line, as a result (a) it can be a challenge scheduling all required valve testing into limited duration outage work windows, (b) at multi unit sites, Unit 0 valves can be difficult to test because they are rarely ever out of service, (c) deuterium-oxide (heavy water) moderator is expensive to manufacture, as a result, effective through valve leakage monitoring is essential. These three factors alone make CANDU sites the most suitable candidates for on line valve monitoring systems. Nuclear industry regulations have been instrumental in the development of 'at the valve' diagnostic systems, but diagnostic testing has not typically been utilized to the same degree in other less regulated industries. However, that trend is changing, and the move toward valve diagnostics and condition monitoring has moved fastest in the offshore oil and gas industry on the Norwegian side of the North Sea. The Ormen Lange plant, located on Nyhamna Island on the west coast of Norway, operated by Shell, is one of the worlds most advanced gas processing plants. A stated maintenance goal for the plant is that 70% of the maintenance budget and spend should be based on the results of on line condition monitoring, utilizing monitoring systems equipped with switch sensing, strain gages, hydraulic and pneumatic pressure transducers and acoustic leakage

  7. Improvements in valve reliability due to implementation of effective condition monitoring programs

    International Nuclear Information System (INIS)

    Modern diagnostic systems for motor-operated valves, pneumatic control valves and checkvalves have facilitated a shift in the maintenance philosophy for valves and actuators in nuclear power plants from schedule based to condition-based maintenance (CBM). This shift enables plant management to focus resources and schedule priority on the plant equipment that warrants attention thereby not wasting resources or increasing the human factors risk on equipment that has not degraded. The most recent initiatives combine condition monitoring with risk/safety insights to focus attention and resonances on the right equipment at the right time consistent with each component's safety-significance. The activities of the ASME working groups responsible for nuclear O and M codes have kept pace with the technology and process improvements necessary to maximize the technical and economic benefits of condition based and risk informed maintenance. This paper discusses adoption of valve condition monitoring in the nuclear power industry, changes to ASME codes and standards during the 90's to facilitate adoption of condition monitoring technology for in-service testing and recent efforts to combine risk insights with condition monitoring strategies to achieve the highest level of valve reliability and nuclear safety without over inflating maintenance cost. (author)

  8. Monitor-Based Statistical Model Checking for Weighted Metric Temporal Logic

    DEFF Research Database (Denmark)

    Bulychev, Petr; David, Alexandre; Larsen, Kim Guldstrand;

    2012-01-01

    We present a novel approach and implementation for ana- lysing weighted timed automata (WTA) with respect to the weighted metric temporal logic (WMTL≤ ). Based on a stochastic semantics of WTAs, we apply statistical model checking (SMC) to estimate and test probabilities of satisfaction with...... desired levels of confidence. Our ap- proach consists in generation of deterministic monitors for formulas in WMTL≤ , allowing for efficient SMC by run-time evaluation of a given formula. By necessity, the deterministic observers are in general approx- imate (over- or under-approximations), but are most...

  9. Efficiency checking of optimum filtering method for monitoring underground nuclear explosions by ionospheric method

    International Nuclear Information System (INIS)

    With use of experimental data, we have checked efficiency of an optimum filtrating method for monitoring underground nuclear explosions (UNE) by an ionospheric method. In the cases of interest the level of signal at the output of optimum filter was in the range of 0.6 to 0.93, and the level of noises was below 0.5. The probability of accurate detection of UNE was assessed as 100%, when the level of decision threshold was higher than 0.5. (author)

  10. Internal flow patterns on heat transfer characteristics of a closed-loop oscillating heat-pipe with check valves using ethanol and a silver nano-ethanol mixture

    Energy Technology Data Exchange (ETDEWEB)

    Bhuwakietkumjohn, N.; Rittidech, S. [Heat Pipe and Thermal Tools Design Research Laboratory (HTDR), Faculty of Engineering, Mahasarakham University, Mahasarakham 44150 (Thailand)

    2010-11-15

    The aim of this research was to investigate the internal flow patterns and heat transfer characteristics of a closed-loop oscillating heat-pipe with check valves (CLOHP/CV). The ratio of number of check valves to meandering turns was 0.2. Ethanol and a silver nano-ethanol mixture were used as working fluids with a filling ratio of 50% by total volume of tube. The CLOHP/CV was made of a glass tube with an inside diameter of 2.4 mm. The evaporator section was 50 mm and 100 mm in length and there were 10 meandering turns. An inclination angle of 90 from horizontal axis was established. The evaporator section was heated by an electric heater and the condenser section was cooled by distilled water. Temperature at the evaporator section was controlled at 85 C, 105 C and 125 C. The inlet and outlet temperatures were measured. A digital camera and video camera were used to observe the flow patterns at the evaporator. The silver nano-ethanol mixture gave higher heat flux than ethanol. When the temperature at the evaporator section was increased from 85 C to 105 C and 125 C. It was found that, the flow patterns occurred as annular flow + slug flow, slug flow + bubble flow and dispersed bubble flow + bubble flow respectively. The main regime of each flow pattern can be determined from the flow pattern map ethanol and a silver nano-ethanol mixture. Each of the two working fluids gave corresponding flow patterns. (author)

  11. Condition monitoring of valve clearance fault on a small four strokes petrol engine using vibration signals

    OpenAIRE

    Songpon Klinchaeam; Pornchai Nivesrangsan

    2010-01-01

    This paper studies condition monitoring technique of a small four strokes, single cylinder petrol engine using vibrationsignal analysis based on time domain, crank angle domain, and signal energy. Vibration signals are acquired from the cylinderhead of the engine and used to describe engine processes such as intake/exhaust valve operations, ignition process, andcombustion process. In this study, vibration signals have been applied to monitor various fault conditions in the engine suchas intak...

  12. Remote monitoring of vacuum and valve status using LabVIEW

    International Nuclear Information System (INIS)

    For remote monitoring of vacuum status in LINAC and associated beam transport lines, a LabVIEW based interface through RS232 communication is developed. All vacuum stations in LINAC are equipped with Pfeiffer pressure measurement units, namely, TPQ 262 (for 2 no.s) and TPG256 (for 6 no.s). The communication to the unit is done via RS232 with the Serial Device Server. The electro-pneumatic gate valves separating beam line sections and cryostats are fitted with limit switches for indicating open/close status. A modular unit based on PIC 18F4520 microcontroller is developed to read the limit switch positions of up to 10 valves. Both the vacuum readout unit and the gate valve monitor unit act as a server to the client PC on the console. Each unit is assigned a unique IP address and connected to the TCP/IP Ethernet bus. The LabVIEW Virtual Instrument based TCP/IP is used for communication through the distributed LAN. It is possible to connect additional client PCs using the LabVIEW Remote Console features. During the accelerator operation the vacuum reading of the gauge and the status of valves can be monitored from the control room console. All the vacuum parameters like gauge value and status at different physical locations are scanned and logged approximately every second. The LabVIEW GUI has helped in making the system user friendly and can be expanded easily. (author)

  13. Motor-operated valve performance testing and condition monitoring using data from the motor control center

    International Nuclear Information System (INIS)

    Much progress has been made over the past 20 years at CANDU nuclear stations to understand and improve Motor-Operated Valve (MOV) performance and reliability. If set up properly, most MOVs show very repeatable and predictable results when tested during outages. In fact, it is believed that, to some extent, a few of the encountered MOV failures stem from repeated maintenance operations and intrusive test methods. In this context, the potential for assessing MOV performance and monitoring their condition using electrical data acquired at the Motor Control Center (MCC) has generated considerable interest over the past few years. The overall approach consists of acquiring current and voltage signals at the MCC to derive motor power and motor torque traces. A correlation between the output parameters typically measured at the valve and the derived motor data is usually established through initial baseline tests. Following subsequent tests at the MCC, several valve performance indicators are derived using the original baseline data and the newly acquired MCC data to assess the valve performance and monitor its condition. The potential benefits from acquiring data at the MCC are the increased trending/monitoring capability and also the cost savings associated with the potential identification of MOVs that may not need 'at-the-valve' testing as initially scheduled. This would help reduce maintenance costs and radiation exposure to personnel. At CANDU stations, MOV testing is currently performed almost exclusively at the valve. Voltage and current are occasionally measured at the MCC to generate motor power traces, but not with the intent of performing extensive MCC-based valve diagnostics since most CANDU stations have yet to acquire the tools required for this type of analysis. In this context, a COG (CANDU Owners Group) R and D program was launched to assess the potential and reliability of the various methods/systems used for MCC valve diagnostic testing. This paper

  14. Condition monitoring of valve clearance fault on a small four strokes petrol engine using vibration signals

    Directory of Open Access Journals (Sweden)

    Songpon Klinchaeam

    2010-12-01

    Full Text Available This paper studies condition monitoring technique of a small four strokes, single cylinder petrol engine using vibrationsignal analysis based on time domain, crank angle domain, and signal energy. Vibration signals are acquired from the cylinderhead of the engine and used to describe engine processes such as intake/exhaust valve operations, ignition process, andcombustion process. In this study, vibration signals have been applied to monitor various fault conditions in the engine suchas intake and exhaust valve clearance faults. Vibration signals acquired in time domain could be mapped onto crank angledomain using top dead center signal. Time domain techniques were used to analyze vibration signals so that the main eventsrelated to the engine operations could be described easily. Using energy analysis technique, all fault conditions could bealso identified. For future work, signal analysis techniques must be developed and the detected signals should be comparedwith other signals such as pressure signal in order to verify the accuracy of the results.

  15. Effect of Evaporator Section Lengths and Working Fluids on Operational Limit of Closed Loop Oscillating Heat Pipes with Check Valves (CLOHP/CV

    Directory of Open Access Journals (Sweden)

    P. Meena

    2009-01-01

    Full Text Available This research aims to the effect of evaporator section lengths and working fluids on operational limit of closed loop oscillating heat pipes with check valves (CLOHP/CV with R123 Ethanol and Water were used as the working fluids. A set of CLOHP/CV was made of copper tubes in combination of following dimension: 1.77 mm inside diameter: 10 turns: 5, 10 and 15 cm equal lengths for evaporator, adiabatic and condenser sections. The working fluid was filled in the tube at the filling ratio of 50%. The evaporator section was given heat by heater while the condenser section was cooled by volume water in a cold bath. The adiabatic section was properly insulated. In the test operation. Which the temperature at the adiabatic section was controlled at 60°C in steady-state condition. From The obtained results obtained, it could be concluded as follows. When the evaporator lengths increased from 5 cm to 10 and 15 cm the critical heat transfer flux decreased. There was working fluids change from R123 to Ethanol and water the critical heat flux decreased.

  16. 仿生创新方法及其在止回阀设计中的应用%A bionic innovation method and its application in check valve design

    Institute of Scientific and Technical Information of China (English)

    赖朝安

    2013-01-01

    Analyses the advantages and disadvantages of TRIZ methods and bionics, the innovative design approach based on a combination of TRIZ and bionics was put forward. The traditional check valves such as ball valve and wafer check valves have some shortcomings, such as the high resistance coefficient. Basing on this method, a new type of pyramid orange-peel check valve was design. When the disc is open,the peels are beside the channel;when the disc is close,the peels are in the form of pyramid, thus,it can effectively reduce the area of obstructing water. Experimental analysis was done for the flow field of the check valve. The results show that the flow resistance coefficient is much less than that of conventional check valve. It also shows that it has better capacity for water flowing and energy conservation.%针对发明问题解决理论(TRIZ)方法与仿生学的优缺点,提出基于TRIZ与仿生学相结合的仿生创新设计方法.采用该方法,针对传统止回阀如球形止回阀、对夹式止回阀等流阻系数大的缺点,设计出一种新型的金字塔型多瓣止回阀,当流体正向流动时,阀瓣打开并位于流道侧面;当流体回流时,阀瓣关闭处于斜立状态,因此可以有效地减少阀瓣开关行程,并减小对流体的阻力与作用时间,降低了流阻系数.实验证明:该止回阀阀门的流通能力很强,能起到一定的节能作用.

  17. Determination of monitor unit check tolerances based on a comparison with measurement and treatment planning system data

    International Nuclear Information System (INIS)

    ABSTRACT: This work describes the experimental validation of treatment planning system monitor unit (MU) calculations against measurement for a range of scenarios. This, together with a comparison of treatment planning system MUs and an independent MU check method, allows the derivation of confidence intervals for the check process. Data were collected for open and 60° motorized wedge fields using an Elekta Synergy linac at 6 and 8 MV using homogeneous and heterogeneous phantoms. Masterplan (Version 4.0) pencil-beam and collapsed cone algorithms were used for the primary MU calculations with full inhomogeneity correction. Results show that both algorithms agree with measurement to acceptable tolerance levels in the majority of the cases studied. The confidence interval for the pencil-beam algorithm MU against an independent check was determined as + 1.6% to −3.4%. This is modified to + 2.3% to −2.5% when data collected with low-density heterogeneities are removed as this algorithm is not used clinically for these cases. The corresponding interval for the collapsed cone algorithm was + 1.2% to −4.3%, indicating that an offset tolerance for the independent check is appropriate. Analysis of clinical conformal treatment plan data generated using the pencil-beam algorithm (1393 beams) returned 93% of beams within the independent check tolerance. Similarly, using the collapsed cone algorithm as the primary MU calculation, 77% (of 1434 beams) were within the confidence interval

  18. Development of an integrated condition monitoring and diagnostic system for motor-operated valves used in nuclear power plant

    International Nuclear Information System (INIS)

    The reliability question of the components, specifically of motor operated valves, became one of the most important issues to be investigated in nuclear power plants, considering security and life plant extension. Therefore, the necessity of improvements in monitoring and diagnosis methods started to be of extreme relevance in the maintenance predictive field, establishing as main goal the reliability and readiness of the system components. Specially in nuclear power plants, the predictive maintenance contributes in the security factor in order to diagnosis in advance the occurrence of a possible failure, preventing severe situations. It also presents a contribution on the economic side by establishing a better maintenance programming, and reducing unexpected shutdown. The development of non intrusive monitoring and diagnostic method makes it possible to identify malfunctions in plant components during normal plant operation. This dissertation presents the development of an integrated condition monitoring system for motor-operated valves used in nuclear power plants. The methodology used in this project is based on the electric motor power signatures analysis, during the closing and opening stroke time of the valve. Once the measurements baseline diagnostic of the motor-operated valve is taken, it is possible to detect long-term deviations during valve lifetime, detecting in advance valve failures. The system implements two parallel techniques for detection and categorization of anomalies: expert system using fuzzy logic based on rules and knowledge base, providing a systematic approach for decision making, and the Wavelet Transform Technique, where the main goal is to obtain more detailed information contained in the measured data, identifying and characterizing the transients phenomena in the time and frequency domains, correlating them to failures situations in the incipient stage. The conditioning monitoring and diagnostic system was designed and implemented at

  19. Monitoring of Erosion Preventive Structures Based on Eco-Engineering Approaches: The Case of the Mixed Check Dams of Masonry and Forest Residues

    Directory of Open Access Journals (Sweden)

    Guillermo Tardio Cerrillo

    2016-05-01

    Full Text Available The mixed check dams were conceived in late 2007, during actions to control the onset of erosion processes in Teide National Park subsequent to a forest fire. A simplified scheme of these mixed check dams consists of a structure of horizontal and vertical wooden elements creating a core that is filled with fine branches and forest residues. Besides this, rocks are placed on both sides of the check dam. The mixed check dam technique follows an eco-engineering design approach. These check dams are temporary structures because their cores will decompose in a few years (from 5-10 years depending on the size of the forest residues used. After our last visit to Tenerife (August 2012, it could be checked that the mixed check dams are providing the predicted results. The sedimentation processes achieved are satisfactory. Based on the collected data during the monitoring stage, the performance of this technique can be already characterised successful.

  20. Development of Injection System with Inner-Set Check Valve for Die Casting Machine%压铸机内置单向阀压射系统的研制

    Institute of Scientific and Technical Information of China (English)

    孟凡义; 徐越; 崔嘉琪

    2012-01-01

    压铸机内置单向阀压射系统,主要解决传统压铸机利用浮动活塞增压的三级压射系统建压时间相对较长引起的缺陷问题.安装在增压活塞杆内的带弹簧复位的内置单向阀,可以借助弹簧的力量快速关闭锥面开始增压,缩短了建压时间.在压射活塞右端与内置单向阀之间增加压射活塞缓冲结构,慢压射时进油口的大小随着压射活塞移动而逐渐增加,实现了慢压射速度匀加速的目的.%Injection system with inner-set check valve for die casting machine was development to solve the problems of the long establishment-time in three-stage injection system in traditional die casting machine due to use floating piston to pressurization. Inner-set check valve with spring reset which was installed in pressurization piston rod could rapidly switch off cone face with the help of spring to shorten established-pressure time by pressurization. Injected piston buffer mechanism was designed between the right end of injected piston and inner-set check valve, so the size of oil entrance during slow injection process is increased gradually with the move of injected piston, realizing the proportional acceleration of slow injection velocity.

  1. Assessment of nonintrusive methods for monitoring the operational readiness of solenoid-operated valves

    International Nuclear Information System (INIS)

    Solenoid-operated valves (SOVs) are being studied at Oak Ridge National Laboratory as part of the USNRC Nuclear Plant Aging Research (NPAR) Program. The primary objective of the study is to identify and recommend methods for inspection, surveillance, and maintenance of SOVs that can ensure their operational readiness-- that is, their ability to perform required safety functions under all anticipated operating conditions. An earlier (Phase I) study described SOV failure modes and causes and identified measurable parameters that might be used to monitor the various degradations that lead to functional failure. The present (Phase II) study focuses on devising and then demonstrating the effectiveness of techniques and/or equipment with which to measure the previously identified performance parameters and thus detect and trend the progress of any degradation. Several nonintrusive techniques are currently under investigation. Recent experimental results which demonstrate the feasibility and practicality of the techniques being studied are presented. 4 refs., 6 figs., 2 tabs

  2. Imaging sensor for monitoring of the piston mechanism in cylindrical valves

    Science.gov (United States)

    Pantiushina, Ekaterina N.; Gorbachev, Alexey A.

    2013-04-01

    Piston-cylinder assemblies are used in various actuator applications in all branches of industry, such as construction technology. It is often important for the operator to know the condition of the piston rod in the pressure-operated cylinder. A large number of operating cycles by this piston can lead to premature failure and breakage of the entire cylinder; this is conditioned by a high chance of splitting of the piston rod due to its elongation during the operating process. Therefore, it is necessary to know their operating lifetimes, for which purpose endurance tests are conducted. Since the pistons are located in hard-to-reach place, monitoring their operation via the contact method while there are in motion is not considered possible. In such situations, a non-contact method is used to monitor to moving parts, which is conducted on the basis of imaging sensors. The authors of this article have developed a new system for conducting endurance test on piston mechanism in a cylindrical valve. This system makes it possible to observe the shift of the reciprocating piston in real time, automate the process of recording data and promptly and accurately measure the parameters of the shift of the piston via a non-contact method and increase the reliability of the data received.

  3. 控制管路系统中止回阀故障分析%Check valve failure analysis in the control piping system

    Institute of Scientific and Technical Information of China (English)

    刘爱明; 蒋廉华; 刘宇; 李开烨

    2013-01-01

    According to the important role of check value which used in the control piping system of electric locomotive .Through analyz-ing the phenomenon of check value failure and the cause of its ,the author gives out some methods .%  针对止回阀在电力机车控制管路系统中所起的重要作用,分析了止回阀的故障现象,对其原因进行探讨,并提出改进方法。

  4. Development of a system for monitoring and diagnosis using Fuzzy logic in control valves of laboratory test equipment of Experimental Center Aramar

    International Nuclear Information System (INIS)

    The question of components reliability, specifically process control valves, has become an important issue to be investigated in nuclear power plants and other areas such as refinery or offshore oil rig, considering the safety and life extension of the plant. The development of non intrusive monitoring and diagnostic method allows the identification of defects in components of the plant during normal operation. The objective of this dissertation is to present an analysis and diagnosis of control valves of a steam plant part that simulates the secondary circuit of a pressurized water reactor. This installation is part of propulsion equipment testing laboratory of the Brazilian Navy, at Ipero-SP. The methodology for design is based on graphical analysis of two parameters, the valve air pressure actuator and the displacement of the valve plug. These data are extracted by a smart positioner, part of Delta V™ Automation System. An analysis is implemented in detecting anomalies by an approach using Expert Systems by the technique of fuzzy logic. Once the basic measures of control valves are taken, it is possible to detect symptoms of failure, leakage, friction, damage, etc. The monitoring and diagnostic system has been designed in MATLAB® version 2009th by the complement 'Fuzzy Logic Toolbox'. It is a noninvasive technique. Thus, it is possible to know what is happening with the chosen components, just analyzing the parameters of the valve. The software called ValveLink® (developed by Emerson) receives signals from hardware component (intelligent positioner) installed next to the control valve. These signals (electrical current) are transformed into information which are used input parameters: air pressure valve actuator and valve plug displacement. With the use of fuzzy logic, these parameters are interpreted. They suffer inferences by rules written by experts in valves. After these inferences, the information is processed and sent as output signals. These

  5. Monitoring of suspended sediments, sediment conditions and aquatic biota during the functional check of bottom outlets

    Science.gov (United States)

    Haun, Stefan; Seitz, Lydia; Stockinger, Wolfram; Riedl, Martin; Schletterer, Martin

    2016-04-01

    Reservoirs are used to store water for multiple purposes and are therefore of great importance for our society. Regularly inspections of the dam structure and the bottom outlets are necessary to ensure a safe operation of these structures. The release of water from the reservoirs for this procedure often results in high suspended sediment concentrations downstream by the remobilization of deposited sediments, which may result further in negative effects on the downstream located habitats. Due to a careful elaborated monitoring concept, e.g. regarding the opening procedure of the bottom outlets, it is possible to change the management strategy and to avoid or to minimize ecological impacts. Within this study a monitoring concept is developed and implemented to observe occurring suspended sediment concentrations during the opening of the bottom outlets of a small reservoir in the alpine region. The measurement concept includes suspended sediment concentration and discharge measurements at the two upstream located tributaries as well as suspended sediment concentration measurements downstream. Two stations are selected downstream with a distance of 750 m and 2,000 m from the dam. To ensure a complete series of concentrations over time bottom samples, Imhoff-cones as well as turbidity meters are implemented. Whereas the turbidity meters ensure a permanent observation of the conditions (will be calibrated with laboratory results from the bottle samples), the Imhoff-cones make it possible to intervene right away into the process of releasing water. A second focus lies on the downstream located river bed, which is monitored before and after the opening of the bottom outlets in order to assess morphodynamical changes such as river bed clogging occurs. Therefore sediment samples with the so called freeze-panel technique are collected before and after the opening of the bottom outlets to quantify possible changes of the bed material. The results show that downstream habitats

  6. Valve Disease

    Science.gov (United States)

    ... Myocarditis Obstructive Sleep Apnea Pericarditis Peripheral Vascular Disease Rheumatic Fever Sick Sinus Syndrome Silent Ischemia Stroke Sudden Cardiac Arrest Vulnerable Plaque Valve Disease | Share Related terms: heart valves, valve insufficiency, valve regurgitation, valve stenosis, valvular ...

  7. Light water reactor pressure isolation valve performance testing

    International Nuclear Information System (INIS)

    The Light Water Reactor Valve Performance Testing Program was initiated by the NRC to evaluate leakage as an indication of valve condition, provide input to Section XI of the ASME Code, evaluate emission monitoring for condition and degradation and in-service inspection techniques. Six typical check and gate valves were purchased for testing at typical plant conditions (550F at 2250 psig) for an assumed number of cycles for a 40-year plant lifetime. Tests revealed that there were variances between the test results and the present statement of the Code; however, the testing was not conclusive. The life cycle tests showed that high tech acoustic emission can be utilized to trend small leaks, that specific motor signature measurement on gate valves can trend and indicate potential failure, and that in-service inspection techniques for check valves was shown to be both feasible and an excellent preventive maintenance indicator. Life cycle testing performed here did not cause large valve leakage typical of some plant operation. Other testing is required to fully understand the implication of these results and the required program to fully implement them. (author)

  8. MO-G-BRE-03: Automated Continuous Monitoring of Patient Setup with Second-Check Independent Image Registration

    International Nuclear Information System (INIS)

    Purpose: To create a non-supervised quality assurance program to monitor image-based patient setup. The system acts a secondary check by independently computing shifts and rotations and interfaces with Varian's database to verify therapist's work and warn against sub-optimal setups. Methods: Temporary digitally-reconstructed radiographs (DRRs) and OBI radiographic image files created by Varian's treatment console during patient setup are intercepted and used as input in an independent registration module customized for accuracy that determines the optimal rotations and shifts. To deal with the poor quality of OBI images, a histogram equalization of the live images to the DDR counterparts is performed as a pre-processing step. A search for the most sensitive metric was performed by plotting search spaces subject to various translations and convergence analysis was applied to ensure the optimizer finds the global minima. Final system configuration uses the NCC metric with 150 histogram bins and a one plus one optimizer running for 2000 iterations with customized scales for translations and rotations in a multi-stage optimization setup that first corrects and translations and subsequently rotations. Results: The system was installed clinically to monitor and provide almost real-time feedback on patient positioning. On a 2 month-basis uncorrected pitch values were of a mean 0.016° with standard deviation of 1.692°, and couch rotations of − 0.090°± 1.547°. The couch shifts were −0.157°±0.466° cm for the vertical, 0.045°±0.286 laterally and 0.084°± 0.501° longitudinally. Uncorrected pitch angles were the most common source of discrepancies. Large variations in the pitch angles were correlated with patient motion inside the mask. Conclusion: A system for automated quality assurance of therapist's registration was designed and tested in clinical practice. The approach complements the clinical software's automated registration in

  9. Rescue therapy using an endobronchial valve and digital air leak monitoring in Invasive Pulmonary Aspergillosis

    Directory of Open Access Journals (Sweden)

    Selina Tsim

    2015-01-01

    Full Text Available In this case report, we describe the utilisation of two recently developed technologies for the successful management of a persistent air leak (PAL in a critically ill patient in whom cardiothoracic surgical intervention was not possible. We report the case of a young leukaemic woman with a PAL complicating Invasive Pulmonary Aspergillosis (IPA, who was effectively managed using an Endobronchial Valve, supplemented by objective, digital air leak data provided by a Thopaz® device (Medela, Switzerland.

  10. Heart valve surgery

    Science.gov (United States)

    Valve replacement; Valve repair; Heart valve prosthesis; Mechanical valves, Prosthetic valves ... made materials, such as metal (stainless steel or titanium) or ceramic. These valves last the longest, but ...

  11. 南水北调中线干线工程渠道逆止阀的施工工艺和质量控制%Construction Technique and Quality Control of Channel Check Valve in the Middle Route of South-to-North Water Diversion Project

    Institute of Scientific and Technical Information of China (English)

    高大勇; 朱云飞

    2013-01-01

    以南水北调鹤壁段第二施工标段为例,介绍了渠道逆止阀的安装工艺,如遵循“基础开挖→回填第一层粗砂→埋置集水暗管→回填暗管周边粗砂→铺设保温板→铺设复合土工膜→安装逆止阀”的施工流程;质量控制方法,如控制逆止阀安装位置、高程、数量等。%The installation technique of channel check valve is introduced by taking the example of Hebi section , the second construction section of South-to-North Water Diversion Project .The technique are in accordance with following orders:foundation excavation , backfilling the first layer of coarse sand , burying water collecting pipe , backfilling coarse sand surrounding pipes , laying warm keeping board , laying composite geomembrane and installing check valve .Mean-while , the quality control methods , such as control check valve installation position , elevation and quantity are also covered .

  12. Door valve

    International Nuclear Information System (INIS)

    Object: To reliably block leakage of inner fluid in a door valve by providing a bellows mechanism in a portion where a valve rod penetrates an oil hydraulic cylinder and by sealing opposite side valve seats of the valve body with an oil hydraulic type seal mechanism. Structure: A door valve comprising a valve body movably provided within a valve casing, an oil hydraulic mechanism driving a valve rod directly connected to the valve body, a bellows mechanism provided on a portion where a valve rod penetrates the cylinder of the oil hydraulic mechanism and an oil hydraulic seal mechanism provided on the inner side of an inlet of the valve casing opposing a valve seat of the valve body, thereby isolating such components as the reactor container, casker, relay container and fuel storage tank at the time of replacement of fuel and reliably preventing leakage of liquid metal vapor containing radioactive material. (Kamimura, M.)

  13. CMM Interim Check (U)

    Energy Technology Data Exchange (ETDEWEB)

    Montano, Joshua Daniel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-03-23

    Coordinate Measuring Machines (CMM) are widely used in industry, throughout the Nuclear Weapons Complex and at Los Alamos National Laboratory (LANL) to verify part conformance to design definition. Calibration cycles for CMMs at LANL are predominantly one year in length. Unfortunately, several nonconformance reports have been generated to document the discovery of a certified machine found out of tolerance during a calibration closeout. In an effort to reduce risk to product quality two solutions were proposed – shorten the calibration cycle which could be costly, or perform an interim check to monitor the machine’s performance between cycles. The CMM interim check discussed makes use of Renishaw’s Machine Checking Gauge. This off-the-shelf product simulates a large sphere within a CMM’s measurement volume and allows for error estimation. Data was gathered, analyzed, and simulated from seven machines in seventeen different configurations to create statistical process control run charts for on-the-floor monitoring.

  14. Liquid metal plasma valve development

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-06-01

    A program for the development of liquid-metal plasma valves (LMPVs) is discussed in detail. The program consisted of two tasks. The first was the development and testing of valves in the laboratory and the fabrication, instrumentation, testing and in-service operation of two valves at the Bonneville Power Adminstration (BPA) facilities of the Pacific Intertie HVDC Power Tansmission System at Celilo, Oregon. The second task was the design, development, fabrication, installation, and operation of a voltage and current monitoring station and the transient event recording system to go with it. Information is present on the design and development of converter valves; LMPV principles; and the testing of prototype valves. (LCL)

  15. Integration of L3 second level triggering in the experiment data acquisition system: online checking and monitoring of the Transputer network

    International Nuclear Information System (INIS)

    The integration of the second level inside the assembly of experimental configuration allows the final realization and system in-situ operation. Two operation modes are authorized: a global operation which ensures the system checking during the period of data acquisition and a local operation mode allowing the material calibrating and testing. The online Level 2 checking is based on an architecture having a structure in accordance with the general experiment; it realizes at the same time the guiding functions and the monitoring tasks of the system. The software test and monitoring architecture of the network is distributed and is identical on all Transputers. It is based on the AServer protocol which establishes the necessary communications between Transputer world and UNIX world. The communications between the UNIX processes are ensured by two unidirectional pipes for instructions and responses, respectively. The AServer communication protocol provided by Inmos allows establishing the communications between Transputers and UNIX. The Level-2 guiding is adapted to the following steps in data acquisition: the tasks launching initiated by an CREATE instruction, the cold starting through a COLD instruction, the system initialization by INIT, starting and stopping the data acquisition by START and STOP, respectively. INIT is taking into account also the immediate parameters i.e. the parameters interactively selected. The paper describes the structure of Transputer code and different in-situ configuration tests. Also there are presented online utilities visualizing the following information: the states of different network transputers controlling the system; the statistics accumulated by the selection algorithms; the possible readout errors at the TMB ports for the Level-2 monitoring

  16. Aging management through condition monitoring of ASCo solenoid valves and NAMCO limit switches

    International Nuclear Information System (INIS)

    Faced with increasing deregulation in the power industry, competition from independent power producers (IPPs) and aging nuclear power plants, utilities are looking at ways to cut their generation costs to remain competitive. Besides the capital and fuel costs that are fixed, utilities are burdened with the ever escalating operation and maintenance costs and are studying means to control aging of their plants and improve plant performance. This paper presents methods for reducing periodic replacement costs for 2 types of equipment. These methods predict and control aging through baseline material characteristic/performance criteria and periodic condition monitoring. The equipment to which these methods are applied have numerous applications in the plant. The methodologies presented herein can be extended to cover all safety and risk significant components in the plant that are either important to plant safety and operation and/or are expensive to replace

  17. Optimum test interval of closing valves

    International Nuclear Information System (INIS)

    The closing valves are the main part of time in stand-by state. It is characteristic that the reliability of the valves decreases during stand-by time. Therefore the valves are tested periodically, in order to check their condition. On the other hand, the testing may cause failures and thus decreases the availability of valves. Through a proper choice of test internal these competing factors can be balanced against each other. Optimum tests interval of closing valves is considered with the aid of simple unavailability models and using reliability data collected from Finnish BWR plants. (orig.)

  18. Inspection systems for valves monitoring at EDF; Systemes d`inspection utilises par EDF pour la surveillance de la robinetterie

    Energy Technology Data Exchange (ETDEWEB)

    Germain, J.L.; Granal, L.; Provost, D.; Touillez, M. [EDF, 75 - Paris (France)]|[Electricite de France (EDF), 78 - Chatou (France)

    1997-10-01

    Electricite de France (EDF) makes increasing use of valve inspection systems to guarantee safety in its pressurized water reactor plants, improve plant availability and facilitate condition-based maintenance. A portable system known as SAMIR has been developed for inspection of motor-operated valves, and is now used on EDF`s 900-MW sites. For its 1300-MW units, EDF has chosen a more complete system which enables measuring thrust on the valve stem during a maneuver, using a sensor mounted on the yoke. To detect internal vale leaks, an on-site assessment has demonstrated the economic benefits of acoustic emission techniques. EDF has equipped its sites with analog leak detection systems which may soon be replaced by a digital model now being developed. (authors).

  19. Depressurization valve

    International Nuclear Information System (INIS)

    A depressurization valve for use in relieving completely the pressure in a simplified boiling water reactor is disclosed. The normally closed and sealed valve is provided with a valve body defining a conduit from an outlet of a manifold from the reactor through a valve seat. A closing valve disk is configured for fitting to the valve seat to normally close the valve. The seat below the disk is provided with a radially extending annulus extending a short distance into the aperture defined by the seat. The disk is correspondingly provided with a longitudinally extending annulus that extends downwardly through the aperture defined by the seat towards the high pressure side of the valve body. A ring shaped membrane is endlessly welded to the seat annulus and to the disk annulus. The membrane is conformed over the confronted surface of the seat and disk in a C-sectioned configuration to seal the depressurization valve against the possibility of weeping. The disk is held to the closed position by an elongate stem extending away from the high pressure side of the valve body. The stem has a flange configured integrally to the stem for bias by two springs. The first spring acts from a portion of the housing overlying the disk on the stem flange adjacent the disk. This spring urges the stem and attached disk away from the seat and thus will cause the valve to open at any pressure. A second spring-preferably of the Belleville variety-acts on a latch plate surrounding and freely moving relative to the end of the stem. This second spring overcomes the bias of the first spring and any pressure acting upon the disk. This Belleville spring maintains through its spring force the valve in the closed position. At the same time, the latch plate with its freedom of movement relative to the stem allows the stem to thermally expand during valve temperature excursion

  20. Uroflowmetric Monitoring and its Role in Evaluating the Results of Surgical Treatment in Children with Urethral Valves

    Directory of Open Access Journals (Sweden)

    Habibullo A. Akilov PhD, ScD¹

    2012-12-01

    Full Text Available This paper presents the results of research and treatments in 41 children (from two months to 15 years of age with urethral valves. In all, 16 patients were treated using the endoscopic method, 7 patients by employing the polyethylene urethrotome and 18 patients treated by the proposed method, using a metallic urethrotome. Diagnosis of the urethral valves was done using ultrasonography, voiding cystourethrogram, urethrocystoscopy, uroflowmetry and cystomanometry. Mathematical modeling was applied to assess the treatment methods. The proposed method, using the metallic urethrotome, was preferable to the endoscopic method.

  1. Simulation of self-actuating valves in piping systems

    International Nuclear Information System (INIS)

    Water and steam loops of large thermal power units are often equipped with self-actuating valves. This means that the kinetic energy of the valve piston is taken from the medium of the loop to be controlled by the valve itself. Three main typs of valves exist: a) damped check valves for one-way motion, b) safety-valves as two level controllers between two pressure levels and c) control-valves as real controllers to control a pressure level or a mass flow, for example. The complexity of geometry and mechanism depends on the function of the valve. To provide engineers with data for piping and valve layout against transient loads it is necessary to perform computations regarding the interaction of the pipe flow and valve kinematics. (orig.)

  2. Leakage characterization of a piloted power operated relief valve

    International Nuclear Information System (INIS)

    In Westinghouse Pressurized Water Reactors (PWRs), power operated relief valves (PORVs) are used to provide overpressure protection of the Pressurizer. The valves are fail closed globe valves which means that power is required to open the valves and, on loss of power, the valves close. There are two ways to operate the PORVs. The more common way is to directly couple the disc to an actuator via a disc-stem assembly. The type of design is not the object of this paper. The other and less common way of operating a PORV is by piloting the main valve such that the opening or closing of a pilot valve opens and closes the main valve. This is the design of interest. In most plants, the PORVs are installed with a water loop seal while in some plants no water loop seals are used. It is generally accepted that loop seal installation minimizes valve seat leakage. In non-loop seal installation, the valve seat is exposed to steam which increases the potential for seat leakage. This paper describes the results of some tests performed with nitrogen and steam to characterize the leakage potential of a pilot operated PORV. The test results were compared with seat leakage tests of check valves to provide insight on the leakage testing of pilot operated valves and check valves. The paper also compares the test data with leakage estimates using the ASME/ANSI OM Code guidance on valve leakage

  3. Development of an effective valve packing program

    Energy Technology Data Exchange (ETDEWEB)

    Hart, K.A.

    1996-12-01

    Current data now shows that graphite valve packing installed within the guidance of a controlled program produces not only reliable stem sealing but predictable running loads. By utilizing recent technological developments in valve performance monitoring for both MOV`s and AOV`s, valve packing performance can be enhanced while reducing maintenance costs. Once known, values are established for acceptable valve packing loads, the measurement of actual valve running loads via the current MOV/AOV diagnostic techniques can provide indication of future valve stem sealing problems, improper valve packing installation or identify the opportunity for valve packing program improvements. At times the full benefit of these advances in material and predictive technology remain under utilized due to simple past misconceptions associated with valve packing. This paper will explore the basis for these misconceptions, provide general insight into the current understanding of valve packing and demonstrate how with this new understanding and current valve diagnostic equipment the key aspects required to develop an effective, quality valve packing program fit together. The cost and operational benefits provided by this approach can be significant impact by the: elimination of periodic valve repacking, reduction of maintenance costs, benefits of leak-free valve operation, justification for reduced Post Maintenance Test Requirements, reduced radiation exposure, improved plant appearance.

  4. Pressure Relief Valve

    Science.gov (United States)

    1985-01-01

    "Sputtering" is the process of applying film-like metal coatings onto a surface by bombarding the coating material with electrocharged ions. This causes the material to disintegrate and relocate on the substrate an atom layer at a time. The process allows a variety of coating materials to be deposited on various surfaces. Deposition Technology, Inc. (DTI) uses "sputtering" for window films, packaging materials, etc. Valves installed on two vacuum chambers which are part of DTI's system, were developed by Lewis Research Center and detailed in Tech Briefs. The valve protects the environment and frees the operator from monitoring the chamber venting.

  5. Regular health checks

    DEFF Research Database (Denmark)

    Grønhøj Larsen, Christian; Jørgensen, Karsten Juhl; Gøtzsche, Peter C

    2012-01-01

    To investigate whether Danish providers of general health checks present a balanced account of possible benefits and harms on their websites and whether the health checks are evidence-based.......To investigate whether Danish providers of general health checks present a balanced account of possible benefits and harms on their websites and whether the health checks are evidence-based....

  6. Plunger with simple retention valve

    International Nuclear Information System (INIS)

    This patent describes a positive displacement retention valve apparatus in which the actual flow equals the theoretical maximum flow through the retention valve. The apparatus includes, in combination, a confined fluid flow conduit, a piston adapted for reciprocal movement within the fluid flow conduit between upstream and downstream limit positions, piston reciprocating means, and pressure responsive check valve means located upstream with respect to the piston in the fluid flow conduit. The pressure responsive check valve means operable to permit fluid flow therethrough in a downstream direction toward the piston, and to preclude fluid flow therethrough in an opposite direction. The piston is composed of parts which are relatively movable with respect to one another. The piston includes a simple retention valve consisting of a plug means, a cylinder having a minimum and a maximum internal cross section flow area therein and being reciprocal within the confined fluid flow conduit, and a seat on the cylinder for the plug means. The piston reciprocating means are operatively connected to the plug means

  7. Design criteria monograph for pressure regulators, relief valves, check valves, burst disks, and explosive valves

    Science.gov (United States)

    1974-01-01

    Monograph reviews and assesses current design practices, and from them establishes firm guidance for achieving greater consistency in design, increased reliability in end product, and greater efficiency in design effort. Five devices are treated separately. Guides to aid in configuration selection are outlined.

  8. Research on technical points for environmental monitoring in municipal solid wasteincinerationproject for check and accept completed project%生活垃圾焚烧项目竣工环保验收监测技术要点研究

    Institute of Scientific and Technical Information of China (English)

    杨丽; 尹卫萍

    2014-01-01

    According to theindustrycharacteristics and the practical experience ,this paper put forward some technical keypointsfor environmental monitoring in municipal solid wasteincineration project for check and accept completed project,from the previous preparation, the program making , the field monitoring, the report writing etc.%结合生活垃圾焚烧项目的行业特点,文章从前期准备、方案制定、现场监测、编制报告等方面,提出该类建设项目竣工环保验收监测时需关注的技术要点。

  9. Annual Check-up

    Science.gov (United States)

    ... Medical Conditions Nutrition & Fitness Emotional Health Annual Check-Up Posted under Health Guides . Updated 7 January 2015. + ... I get ready for my annual medical check-up? If this is your first visit to your ...

  10. Checking Java Programs

    CERN Document Server

    Darwin, Ian

    2007-01-01

    This Short Cut tells you about tools that will improve the quality of your Java code, using checking above and beyond what the standard tools do, including: Using javac options, JUnit and assertions Making your IDE work harder Checking your source code with PMD Checking your compiled code (.class files) with FindBugs Checking your program's run-time behavior with Java PathFinder

  11. [Valve-in-valve with Portico valve for a degenerative bioprosthetic surgical valve (Biocor)].

    Science.gov (United States)

    Latini, Roberto Adriano; Testa, Luca; Brambilla, Nedy; Tusa, Maurizio; Bedogni, Francesco

    2016-04-01

    In the last years, a general shift toward the use of surgical bioprosthetic aortic valves rather than mechanical valves with subsequent less use of anticoagulant therapy has been observed. However, bioprosthetic valves have limited durability. Reoperation, the current standard of care for these patients, carries a high surgical risk, especially because patients are elderly and with numerous comorbidities. Recently, transcatheter aortic valve replacement within a failed bioprosthetic valve (valve-in-valve procedure) has proven feasible. We here describe a case of valve-in-valve procedure with a Portico valve placed in a purely insufficient bioprosthetic valve (Biocor). PMID:27093211

  12. Piezoelectric valve

    Science.gov (United States)

    Petrenko, Serhiy Fedorovich

    2013-01-15

    A motorized valve has a housing having an inlet and an outlet to be connected to a pipeline, a saddle connected with the housing, a turn plug having a rod, the turn plug cooperating with the saddle, and a drive for turning the valve body and formed as a piezoelectric drive, the piezoelectric drive including a piezoelectric generator of radially directed standing acoustic waves, which is connected with the housing and is connectable with a pulse current source, and a rotor operatively connected with the piezoelectric generator and kinematically connected with the rod of the turn plug so as to turn the turn plug when the rotor is actuated by the piezoelectric generator.

  13. Valve's Way

    DEFF Research Database (Denmark)

    Foss, Nicolai Juul; Dobrajska, Magdalena

    2015-01-01

    what extent it represents a new blueprint for organization design, despite it being consistent with an “egalitarian Zeitgeist” (Puranam, 2014). In fact, managerial authority may be of increasing importance rather than the opposite (Guadalupe, Li, & Wulf, 2015). Thus, Valve is, and will remain, an...

  14. Use of neural networks to monitor power plant components

    International Nuclear Information System (INIS)

    A new methodology is presented for nondestructive evaluation (NDE) of check valve performance and degradation. Artificial neural network (ANN) technology is utilized for processing frequency domain signatures of check valves operating in a nuclear power plant (NPP). Acoustic signatures obtained from different locations on a check valve are transformed from the time domain to the frequency domain and then used as input to a pretrained neural network. The neural network has been trained with data sets corresponding to normal operation, therefore establishing a basis for check valve satisfactory performance. Results obtained from the proposed methodology demonstrate the ability of neural networks to perform accurate and quick evaluations of check valve performance

  15. Recent NRC research activities addressing valve and pump issues

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, D.L.

    1996-12-01

    The mission of the U.S. Nuclear Regulatory Commission (NRC) is to ensure the safe design, construction, and operation of commercial nuclear power plants and other facilities in the U.S.A. One of the main roles that the Office of Nuclear Regulatory Research (RES) plays in achieving the NRC mission is to plan, recommend, and implement research programs that address safety and technical issues deemed important by the NRC. The results of the research activities provide the bases for developing NRC positions or decisions on these issues. Also, RES performs confirmatory research for developing the basis to evaluate industry responses and positions on various regulatory requirements. This presentation summarizes some recent RES supported research activities that have addressed safety and technical issues related to valves and pumps. These activities include the efforts on determining valve and motor-operator responses under dynamic loads and pressure locking events, evaluation of monitoring equipment, and methods for detecting and trending aging of check valves and pumps. The role that RES is expected to play in future years to fulfill the NRC mission is also discussed.

  16. Condition monitoring a key component in the preventive maintenance

    International Nuclear Information System (INIS)

    The preventive maintenance programs are necessary to ensure that nuclear safety significant equipment will function when it is supposed to. Diesel generator, pumps, motor operated valves and air operated control valves are typically operated every three months. When you drive a car, you depend on lot of sounds, the feel of the steering wheel and gauges to determine if the car is running correctly. Similarly with operating equipment for a power plant - sounds or vibration of the equipment or the gauges and test equipment indicate a problem or degradation, actions are taken to correct the deficiency. Due to safety and economical reason diagnostic and monitoring systems are of growing interest in all complex industrial production. Diagnostic systems are requested to detect, diagnose and localize faulty operating conditions at an early stage in order to prevent severe failures and to enable predictive and condition oriented maintenance. In this context it is a need for using various on-line and off-line condition monitoring and diagnostics, non-destructive inspection techniques and surveillance. The condition monitoring technique used in nuclear power plant Cernavoda are presented in this paper. The selection of components and parameters to be monitored, monitoring and diagnostics techniques used are incorporated into a preventive maintenance program. Modern measurement technique in combination with advanced computerized data processing and acquisition show new ways in the field of machine surveillance. The diagnostic capabilities of predictive maintenance technologies have increased recently year with advances made in sensor technologies. The paper will focus on the following condition monitoring technique: - oil analysis - acoustic leakage monitoring - thermography - valve diagnostics: motor operated valve, air operated valve and check valve - motor current signature - vibration monitoring and rotating machine monitoring and diagnostics For each condition monitoring

  17. Development of a system for monitoring and diagnosis using Fuzzy logic in control valves of laboratory test equipment of Experimental Center Aramar; Desenvolvimento de um sistema de monitoracao e diagnostico utilizando logica Fuzzy aplicado a valvulas de controle de processo do CEA - Centro Experimental Aramar

    Energy Technology Data Exchange (ETDEWEB)

    Porto Junior, Almir Carlos Soares

    2014-07-01

    The question of components reliability, specifically process control valves, has become an important issue to be investigated in nuclear power plants and other areas such as refinery or offshore oil rig, considering the safety and life extension of the plant. The development of non intrusive monitoring and diagnostic method allows the identification of defects in components of the plant during normal operation. The objective of this dissertation is to present an analysis and diagnosis of control valves of a steam plant part that simulates the secondary circuit of a pressurized water reactor. This installation is part of propulsion equipment testing laboratory of the Brazilian Navy, at Ipero-SP. The methodology for design is based on graphical analysis of two parameters, the valve air pressure actuator and the displacement of the valve plug. These data are extracted by a smart positioner, part of Delta V™ Automation System. An analysis is implemented in detecting anomalies by an approach using Expert Systems by the technique of fuzzy logic. Once the basic measures of control valves are taken, it is possible to detect symptoms of failure, leakage, friction, damage, etc. The monitoring and diagnostic system has been designed in MATLAB® version 2009{sup th} by the complement 'Fuzzy Logic Toolbox'. It is a noninvasive technique. Thus, it is possible to know what is happening with the chosen components, just analyzing the parameters of the valve. The software called ValveLink® (developed by Emerson) receives signals from hardware component (intelligent positioner) installed next to the control valve. These signals (electrical current) are transformed into information which are used input parameters: air pressure valve actuator and valve plug displacement. With the use of fuzzy logic, these parameters are interpreted. They suffer inferences by rules written by experts in valves. After these inferences, the information is processed and sent as output signals

  18. Fabrication of micro metallic valve and pump

    Science.gov (United States)

    Yang, Ming; Kabasawa, Yasunari; Ito, Kuniyoshi

    2010-03-01

    Fabrication of micro devices by using micro metal forming was proposed by the authors. We developed a desktop servo-press machine with precise tooling system. Precise press forming processes including micro forging and micro joining has been carried out in a progressive die. In this study, micro metallic valve and pump were fabricated by using the precise press forming. The components are made of sheet metals, and assembled in to a unit in the progressive die. A micro check-valve with a diameter of 3mm and a length of 3.2mm was fabricated, and the property of flow resistance was evaluated. The results show that the check valve has high property of leakage proof. Since the valve is a unit parts with dimensions of several millimeters, it has advantage to be adapted to various pump design. Here, two kinds of micro pumps with the check-valves were fabricated. One is diaphragm pump actuated by vibration of the diaphragm, and another is tube-shaped pump actuated by resonation. The flow quantities of the pumps were evaluated and the results show that both of the pumps have high pumping performance.

  19. Aortic valve bypass

    DEFF Research Database (Denmark)

    Lund, Jens T; Jensen, Maiken Brit; Arendrup, Henrik; Ihlemann, Nikolaj

    2013-01-01

    In aortic valve bypass (AVB) a valve-containing conduit is connecting the apex of the left ventricle to the descending aorta. Candidates are patients with symptomatic aortic valve stenosis rejected for conventional aortic valve replacement (AVR) or transcatheter aortic valve implantation (TAVI...

  20. Thermodynamic Pressure/Temperature Transducer Health Check

    Science.gov (United States)

    Immer, Christopher D. (Inventor); Eckhoff, Anthony (Inventor); Medelius, Pedro J. (Inventor); Deyoe, Richard T. (Inventor); Starr, Stanley O. (Inventor)

    2004-01-01

    A device and procedure for checking the health of a pressure transducer in situ is provided. The procedure includes measuring a fixed change in pressure above ambient pressure and a fixed change in pressure below ambient pressure. This is done by first sealing an enclosed volume around the transducer with a valve. A piston inside the sealed volume is increasing the pressure. A fixed pressure below ambient pressure is obtained by opening the valve, driving the piston The output of the pressure transducer is recorded for both the overpressuring and the underpressuring. By comparing this data with data taken during a preoperative calibration, the health of the transducer is determined from the linearity, the hysteresis, and the repeatability of its output. The further addition of a thermometer allows constant offset error in the transducer output to be determined.

  1. Seismic qualification tests of nuclear service pressure relief valves

    International Nuclear Information System (INIS)

    This paper reports on the pressure relief valves which provide an overpressure protection of vessels and piping in the nuclear power plant. A seismic qualification of these valves is essential to ensure their structural integrity and operability under earthquake and other dynamic conditions. Four spring loaded pressure relief valves were qualified by dynamic testing in response to a need for an overseas nuclear power plant construction. The test valves were actual production valves in 3/4 to 3 inch sizes and weighed approximately 11 to 110 lb. Each valve was subjected to triaxial random multifrequency testing (RMF), resonance search testing, sine beat testing and impact resonance search testing. Very briefly, the dynamic test conditions enveloped the specified required response spectra (RRS) and required input motion (RIM) vibratory conditions. Each valve input motion (RIM) vibratory conditions. Each valve was also tested to determine valve action, opening pressure and lift characteristics prior to, during, and after various dynamic tests. The valve leakage was also checked except during the dynamic testing. The test results showed very satisfactory operability of all four valves before, during and after the dynamic tests. These and other geometrically/functionally similar valves have also met the seismic qualification requirements of several other domestic and overseas nuclear power plants

  2. Regulatory Conformance Checking: Logic and Logical Form

    Science.gov (United States)

    Dinesh, Nikhil

    2010-01-01

    We consider the problem of checking whether an organization conforms to a body of regulation. Conformance is studied in a runtime verification setting. The regulation is translated to a logic, from which we synthesize monitors. The monitors are evaluated as the state of an organization evolves over time, raising an alarm if a violation is…

  3. Mitral Valve Disease

    Science.gov (United States)

    ... Tricuspid Valve Disease Cardiac Rhythm Disturbances Thoracic Aortic Aneurysm Pediatric and Congenital Heart Disease Heart abnormalities that are ... Transplantation End-stage Lung Disease Adult Lung Transplantation Pediatric Lung ... Aortic Aneurysm Mitral Valve Disease Overview The mitral valve is ...

  4. Health Check Tools

    Science.gov (United States)

    ... https://www.nlm.nih.gov/medlineplus/healthchecktools.html Health Check Tools To use the sharing features on ... Schedule (Centers for Disease Control and Prevention) Children's Health Body Mass Index: Calculator for Child and Teen ( ...

  5. Check It Out

    Science.gov (United States)

    ... Materials The Healthy Heart Handbook for Women Check it Out Tests That Can Help Protect Your Heart ... years, or more often if your doctor recommends it. Other Tests There also are several tests that ...

  6. Goat production check list

    DEFF Research Database (Denmark)

    Henriksen, Jørgen; Nielsen, Mette Benedicte Olaf; Madsen, Jørgen;

    2009-01-01

    This check list, financed by DanChurchAid, highlights all issues should be carefully investigated before investing in distribution of goats and in interventions to assist poor rural communities to improve their livelihood through goat production.......This check list, financed by DanChurchAid, highlights all issues should be carefully investigated before investing in distribution of goats and in interventions to assist poor rural communities to improve their livelihood through goat production....

  7. Motion analysis of mechanical heart valve prosthesis utilizing high-speed video

    Science.gov (United States)

    Adlparvar, Payam; Guo, George; Kingsbury, Chris

    1993-01-01

    The Edwards-Duromedics (ED) mechanical heart valve prosthesis is of a bileaflet design, incorporating unique design features that distinguish its performance with respect to other mechanical valves of similar type. Leaflet motion of mechanical heart valves, particularly during closure, is related to valve durability, valve sounds and the efficiency of the cardiac output. Modifications to the ED valve have resulted in significant improvements with respect to leaflet motion. In this study a high-speed video system was used to monitor the leaflet motion of the valve, and to compare the performance of the Modified Specification to that of the Original Specification using a St. Jude Medical as a control valve.

  8. Microfluidic sieve valves

    Science.gov (United States)

    Quake, Stephen R; Marcus, Joshua S; Hansen, Carl L

    2015-01-13

    Sieve valves for use in microfluidic device are provided. The valves are useful for impeding the flow of particles, such as chromatography beads or cells, in a microfluidic channel while allowing liquid solution to pass through the valve. The valves find particular use in making microfluidic chromatography modules.

  9. Remote actuated valve implant

    Energy Technology Data Exchange (ETDEWEB)

    McKnight, Timothy E.; Johnson, Anthony; Moise, Kenneth J.; Ericson, Milton Nance; Baba, Justin S.; Wilgen, John B.; Evans, Boyd Mccutchen

    2016-05-10

    Valve implant systems positionable within a flow passage, the systems having an inlet, an outlet, and a remotely activatable valve between the inlet and outlet, with the valves being operable to provide intermittent occlusion of the flow path. A remote field is applied to provide thermal or magnetic activation of the valves.

  10. Zero-leak valve

    Science.gov (United States)

    Macglashan, W. F., Jr.

    1980-01-01

    Zero-leakage valve has fluid-sealing diaphragm support and flat sievelike sealing surface. Diaphragm-support valve is easy to fabricate and requires minimum maintenance. Potential applications include isolation valve for waste systems and remote air-actuated valve. Device is also useful in controlling flow of liquid fluorine and corrosive fluids at high pressures.

  11. Remote actuated valve implant

    Science.gov (United States)

    McKnight, Timothy E; Johnson, Anthony; Moise, Jr., Kenneth J; Ericson, Milton Nance; Baba, Justin S; Wilgen, John B; Evans, III, Boyd McCutchen

    2014-02-25

    Valve implant systems positionable within a flow passage, the systems having an inlet, an outlet, and a remotely activatable valve between the inlet and outlet, with the valves being operable to provide intermittent occlusion of the flow path. A remote field is applied to provide thermal or magnetic activation of the valves.

  12. Discussion on Audit the Monitoring Report of Environment Protection for Check and Accept of Completed Construction Project%建设项目竣工环境保护验收监测报告的审核

    Institute of Scientific and Technical Information of China (English)

    成国兴; 吴旻妍; 吴福全

    2013-01-01

    The connotation and characteristics of monitoring report of environment protection for check and accept of completed construction project were expounded. A summary of the technical method requirement of report audit was proposed according to normalizing the audit program, optimizing the audit method and getting hold of the audit keys. Suzhou environment monitoring station was use as an example. The audit process was network based. The detailed requirements for auditor were introduced. The audit program shows scientificity and accountability. Such problems were further discussed as retest, timeliness and sensitive environment monitoring during the course of audit.%简述了建设项目竣工环境保护验收监测报告的内涵和特点,从规范审核程序、优选审核方法、把握审核重点等方面总结了验收监测报告审核的技术方法与要求,并以苏州市环境监测中心站为例,介绍了网络化管理审核流程,以及对审核人员的具体要求,突出审核过程的科学性和责任性.对实际审核过程中有关复测、时效性以及环境敏感点监测等问题作了进一步的探讨.

  13. Flow oscillation on the steam control valve. Effects of valve/valve seat shape in the middle opening, and a possibility of a shock oscillation in the large opening

    International Nuclear Information System (INIS)

    A steam control valve causes vibration of the piping when the opening is in the middle condition. For the rationalization of maintenance and management in the plant, the valve should be improved, but it is difficult to understand the flow characteristics in detail by experiment because the flow around the valve is complex 3D structure and becomes supersonic (M>1). Therefore, it is necessary to clarify the cause of vibration and to develop improvements by the latest CFD (Computational Fluid Dynamics) technology. In current research, we found a valve-attached flow occurs and causes a quasi-periodic spike-type pressure fluctuation at only the middle opening condition in rigid support condition. As this fluctuation causes cyclic side load on the valve body, it is thought to be the cause of vibration. In this report, we examined the flow condition in the large opening condition with our CFD code, 'MATIS', and found a possibility of the shock wave oscillation around valve. As this phenomenon also causes large pressure fluctuation, we need to check the controllability of the shock oscillation with new shape valve in the future. This report also describes an effect of the valve/valve seat to control the pressure fluctuation in the middle opening that is clarified last year. First, we conducted the experiment of the valve seat effect, but it's impossible to control the flow fluctuation completely. Then, we suggest new shape valves (cut valve, extended valve) and checked their performance with 2 types of valve seat. As a result, extended valve can control the fluctuation completely with all valve seat shape. (author)

  14. Checking for Ketones

    Science.gov (United States)

    ... by Mail Close www.diabetes.org > Living With Diabetes > Treatment and Care > Blood Glucose Testing Share: Print Page Text Size: ... glucose-and-a1c, In this section Living With Diabetes Treatment and Care Blood Glucose Testing Checking Your Blood Glucose A1C ...

  15. Automated troubleshooting of pneumatically operated control valves

    International Nuclear Information System (INIS)

    Many control valve applications are critical to the generation of electric power. This paper presents an approach that will minimize maintenance support required for a given control valve as well as assuring that it performs properly, reducing losses associated with process fluid leakage and trim damage. The first portion of this work presents a free-body diagram of a typical control valve-spring and diaphragm actuator assembly, showing how it operates and how all force elements interact. That is, it shows how increased stem friction can reduce the valve seating load; how minor variations in spring adjustment can produce large variations in seating load, etc. After the basics have been covered, the diagnostic system is presented and explained. The system in practice is connected to a valve-actuator assembly so that such things as diaphragm pressure, stem movement and operating signals can be monitored and the data used as input to a portable personal computer and data logger. The valve actuator assembly is then stroked and the inputs monitored. The computer, having been properly programmed taking into account the valve construction and service conditions, then generates a printed report summarizing the condition of the valve in such areas as: spring adjustment, stroking time, valve travel, stem friction, seat load, and positioner and transducer calibration. This evaluation, which should require one or two hours, can pinpoint operational problems before they become the source of process losses or, in the worst case, unscheduled shutdowns. It should also prove to be an excellent maintenance planning tool, allowing evaluation of valves before an outage, so that proper maintenance scheduling can be done in advance

  16. Intrabronchial Valves

    Science.gov (United States)

    Mahajan, Amit Kumar; Verhoef, Philip; Patel, Shruti B.; Carr, Gordon; Hogarth, Douglas Kyle

    2016-01-01

    Background Bronchopleural fistulas (BPF) are conditions associated with prolonged hospital course, high morbidity, and possibly increased mortality. The presence of BPFs in critically ill patients may cause difficulty in ventilation and increased oxygen requirements. Intrabronchial valves (Spiration IBV) serve as a noninvasive therapeutic option for the closure of BPFs. Methods This report is a retrospective description of 3 patients transferred to our medical intensive care unit (ICU) with BPFs and persistent air leaks (PAL). One patient required high levels of oxygen supplementation through a nonrebreather face mask, whereas 2 required mechanical ventilation because of respiratory failure. IBVs were placed in each patient with the intention of closing their BPF and weaning them from respiratory support. Results The use of IBVs in ICU patients with BPFs and PALs resulted in 1 patient being weaned from the persistent need for a nonrebreather face mask to room air and also aided in the liberation from mechanical ventilation of 2 patients who had been failing spontaneous breathing trials. Conclusions The use of IBVs is safe and well tolerated in ICU patients with BPFs and PALs. The placement of IBVs results in significant clinical improvement, allowing for either weaning from high levels of oxygen support or liberation from mechanical ventilation. PMID:23207358

  17. Preliminary assessment of valve IST effectiveness

    International Nuclear Information System (INIS)

    A preliminary review of inservice testing effectiveness for Code Class 1,2, and 3 valves at nuclear power plants was performed. These requirements are specified by the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section XI, and the Operations and Maintenance Standard. The Institute of Nuclear Power Operations Nuclear Plant Reliability Data System (NPRDS) database was used to provide failure reports for these components for 1988 to 1992. This time period coincides with the issuance of Generic Letter 89-04, which resulted in a more consistent application of the requirements by the licensees. For this time period, 8,593 valve failures were identified. From the review of the NPRDS database, the primary failure causes and failure modes for motor-operated valves (MOV), air-operated valves (AOV), and check valves (CV) were identified. Solenoid-operated valves were not reviewed in this study. Plant testing programs were effective in identifying approximately 60% of the CV failures, 46% of the AOV failures, and 44% of the MOV failures

  18. Drug-related cardiac valve disease.

    Science.gov (United States)

    2013-12-01

    Cardiac valve disease can involve one or more of the four heart valves. Chronic valve damage may remain asymptomatic for long periods but ultimately leads to haemodynamic overload of the heart. The most common causes of valve disease are rheumatic diseases, infections, chronic renal failure, malformations, and genetic diseases. Valve disease is often attributed to degeneration with no known cause.The frequency of drug-related valve disease has long been underestimated. Most implicated drugs have serotonergic properties, such as fenfluramine-derived amphetamines, including benfluorex. Rye ergot derivatives can also be implicated: these include dopamine agonists (bromocriptine, lisuride, pergolide and cabergoline), migraine treatments (methysergide, ergotamine and dihydroergotamine), and drugs used for cognitive and neurosensory deficits (nicergoline, dihydroergocryptine, etc.). "Ecstasy", an amphetamine, is sometimes also involved. The risk increases after a few months of exposure. Drug withdrawal is sometimes followed by an improvement. Patients exposed to a drug known to cause valve damage should be informed of the risk and receive long-term monitoring to detect these lesions before they become irreversible. The possible role of a drug should always be considered when cardiac valve disease is diagnosed, in order to facilitate active research and to avoid exposing other patients to this risk. PMID:24600729

  19. CHECK-IN/CHECK-OUT: A SYSTEMATIC EVALUATION AND COMPONENT ANALYSIS

    OpenAIRE

    Campbell, Amy; Anderson, Cynthia M.

    2011-01-01

    Tier 2 interventions are implemented similarly across students and thus serve as an efficient and cost-effective method of behavior support in school settings. Check-in/check-out is a Tier 2 intervention with documented effectiveness (e.g., Hawken & Horner, 2003; Todd, Campbell, Meyer, & Horner, 2008). Key features of the intervention include brief morning and afternoon meetings with the intervention coordinator, use of a point card on which the teacher monitors student behavior, and teacher ...

  20. Which valve is which?

    Directory of Open Access Journals (Sweden)

    Pravin Saxena

    2015-01-01

    Full Text Available A 25-year-old man presented with a history of breathlessness for the past 2 years. He had a history of operation for Tetralogy of Fallot at the age of 5 years and history suggestive of Rheumatic fever at the age of 7 years. On echocardiographic examination, all his heart valves were severely regurgitating. Morphologically, all the valves were irreparable. The ejection fraction was 35%. He underwent quadruple valve replacement. The aortic and mitral valves were replaced by metallic valve and the tricuspid and pulmonary by tissue valve.

  1. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... in our practice, those being tissue valves and mechanical valves. Tissue valves, if I can demonstrate here, ... can expect. This is an example of a mechanical heart valve which is made out of pyrolitic ...

  2. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... up offering patients aortic valve surgery in our community. Aortic stenosis is a process by which the ... basic valve types that we use in our practice, those being tissue valves and mechanical valves. Tissue ...

  3. Training aids: the motor operator valve trainer

    International Nuclear Information System (INIS)

    The spectrum of training aids used in the nuclear industry runs the gamut from the very basic (i.e., valve training aids - gate, globe, check) to the highly complex (i.e., nuclear full scope simulator). Designing and purchasing the best training aids take much time, detailed investigation, and good understanding of plant operations. The training aid that has given the New York Power Authority the best results has been the motor operator valve (MOV) trainer. Some of the items that make the MOV trainer a good choice are: (1) large number of MOVs in the plant, (2) importance of MOVs to safe plant operation, (3) detailed MOV procedures used by the plant, (4) history of MOV problems, and (5) ability to demonstrate important concepts and operation - hammer blow effect, torque and limit switch adjustment and functions, and actual sequence of operation of the limitorque valve operator

  4. Aortic Valve Disease

    Science.gov (United States)

    ... valve opens when the left ventricle squeezes to pump out blood, and closes in between heart beats to keep ... the left ventricle has to work harder to pump blood out through the valve. To do this extra ...

  5. Mitral valve prolapse

    Science.gov (United States)

    ... seen with some connective tissue disorders such as Marfan syndrome and other rare genetic disorders. Symptoms Many ... 66. Read More Atrial septal defect (ASD) Endocarditis Marfan syndrome Mitral valve surgery - minimally invasive Mitral valve ...

  6. Isolated Pulmonary Valve Endocarditis

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Hatamizadeh

    2009-06-01

    Full Text Available Infective endocarditis is one of the most severe complications of parenteral drug abuse. The outstanding clinical feature of infective endocarditis in intravenous drug abusers is the high incidence of right-sided valve infection, and the tricuspid valve is involved in 60% to 70% of the cases. We herein report a case of isolated pulmonic valve infective endocarditis with a native pulmonary valve.

  7. Transcatheter Pulmonary Valve Replacement

    OpenAIRE

    Ghawi, Hani; Kenny, Damien; Hijazi, Ziyad M.

    2012-01-01

    Transcatheter pulmonary valve replacement (tPVR) has evolved into a viable alternative to surgical conduit or bioprosthetic valve replacement. This procedure has paved the way for a more advanced approach to congenital and structural interventional cardiology. Although many successes have been noted, there are still a number of challenges with this procedure, including large delivery systems, the need for a conduit or a bioprosthetic valve as a landing zone for the valve, optimal timing of th...

  8. Root cause evaluation of pressurizer relief valve leakage

    International Nuclear Information System (INIS)

    Pressurizer relief valves at two pressurized water reactor units experienced unacceptable leakage during plant heatup. The leakage was suspected to be caused by excessive pipe loads on the valves. This paper describes how monitoring via hard-wired transducers and a digital data acquisition system was used to quantify the pipe loads on the valves, and assist in determining the root cause of the pipe loads and appropriate corrective actions. The selection of the parameters monitored, how the monitoring was accomplished and interpretation of the results is discussed. The corrective actions implemented based on the monitoring results are also discussed

  9. Heart Valve Diseases

    Science.gov (United States)

    Your heart has four valves. Normally, these valves open to let blood flow through or out of your heart, and then shut to keep it from flowing ... close tightly. It's one of the most common heart valve conditions. Sometimes it causes regurgitation. Stenosis - when ...

  10. A remote control valve

    International Nuclear Information System (INIS)

    This invention concerns a remote control valve for shutting off or distributing a fluid flowing at a high rate and low pressure. Among the different valves at present in use, electric valves are the most recommended for remote control but their reliability is uncertain and they soon become costly when large diameter valves are used. The valve described in this invention does away with this drawback owing to its simplicity and the small number of moving parts, this makes it particularly reliable. It mainly includes: a tubular body fitted with at least one side opening; at least one valve wedge for this opening, coaxial with the body, and mobile; a mobile piston integral with this wedge. Several valves to the specifications of this invention can be fitted in series (a shut-off valve can be used in conjunction with one or more distribution valves). The fitting and maintenance of the valve is very simple owing to its design. It can be fabricated in any material such as metals, alloys, plastics and concrete. The structure of the valve prevents the flowing fluid from coming into contact with the outside environment, thereby making it particularly suitable in the handling of dangerous or corrosive fluids. Finally, the opening and shutting of the valve occurs slowly, thereby doing away with the water hammer effect so frequent in large bore pipes

  11. Checking Model Transformation Refinement

    OpenAIRE

    Büttner, Fabian; Egea, Marina; Guerra, Esther; Lara, Juan De

    2013-01-01

    The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-38883-5_15 Proceedings of 6th International Conference, ICMT 2013, Budapest, Hungary, June 18-19, 2013 Refinement is a central notion in computer science, meaning that some artefact S can be safely replaced by a refinement R, which preserves S’s properties. Having available techniques and tools to check transformation refinement would enable (a) the reasoning on whether a transformation correctly impl...

  12. Respiratory exposure control valve

    International Nuclear Information System (INIS)

    We have designed a new, three-way valve that separates inhaled and exhaled air in systems for inhalation exposure. A single-channel model of the valve was constructed and tested: with a control fluid pressure of 10 psi, the valve was cycled 36,000 times without diaphragm failure. No valve leakage was detected before or after the completion of the test. A 3-channel valve model was constructed this year and will undergo testing in FY 1979, followed by development and testing of the control system

  13. 49 CFR 178.338-8 - Pressure relief devices, piping, valves, and fittings.

    Science.gov (United States)

    2010-10-01

    ...) Pipe joints must be threaded, welded or flanged. If threaded pipe is used, the pipe and fittings must... connection to that coil must be provided with a valve or check valve as close to the tank shell as practicable to prevent the loss of vapor from the tank in case of damage to the coil. The liquid connection...

  14. Relief valve testing study

    International Nuclear Information System (INIS)

    Reclosing pressure-actuated valves, commonly called relief valves, are designed to relieve system pressure once it reaches the set point of the valve. They generally operate either proportional to the differential between their set pressure and the system pressure (gradual lift) or by rapidly opening fully when the set pressure is reached (pop action). A pop action valve allows the maximum fluid flow through the valve when the set pressure is reached. A gradual lift valve allows fluid flow in proportion to how much the system pressure has exceeded the set pressure of the valve (in the case of pressure relief) or has decreased below the set pressure (vacuum relief). These valves are used to protect systems from over and under pressurization. They are used on boilers, pressure vessels, piping systems and vacuum systems to prevent catastrophic failures of these systems, which can happen if they are under or over pressurized beyond the material tolerances. The construction of these valves ranges from extreme precision of less than a psi tolerance and a very short lifetime to extremely robust construction such as those used on historic railroad steam engines that are designed operate many times a day without changing their set pressure when the engines are operating. Relief valves can be designed to be immune to the effects of back pressure or to be vulnerable to it. Which type of valve to use depends upon the design requirements of the system

  15. Main Oxidizer Valve Design

    Science.gov (United States)

    Addona, Brad; Eddleman, David

    2015-01-01

    A developmental Main Oxidizer Valve (MOV) was designed by NASA-MSFC using additive manufacturing processes. The MOV is a pneumatically actuated poppet valve to control the flow of liquid oxygen to an engine's injector. A compression spring is used to return the valve to the closed state when pneumatic pressure is removed from the valve. The valve internal parts are cylindrical in shape, which lends itself to traditional lathe and milling operations. However, the valve body represents a complicated shape and contains the majority of the mass of the valve. Additive manufacturing techniques were used to produce a part that optimized mass and allowed for design features not practical with traditional machining processes.

  16. Automatic checking system of radioactivity in motor-cars 'AKKORD'

    International Nuclear Information System (INIS)

    A monitoring device has been developed for an automated checking of all vehicles leaving or entering a nuclear installation against uncontrolled lost of radioactive material. This device is an excellent tool for radioactive material flow control. (orig.)

  17. Combating automative engine valve recession

    OpenAIRE

    Lewis, R; Dwyer-Joyce, R.S.

    2003-01-01

    [INTRODUCTION] Valve recession occurs when wear of the valve or seat inserts in an automotive engine has caused the valve to sink or recede into the seat insert (as shown in Figure 1). Excessive recession leads to valves not seating correctly and cylinder pressure loss. Leaking hot combustion gases can also cause valve guttering or torching, which will accelerate valve failure. Although new valve materials and production techniques are constantly being developed, these advances h...

  18. Bounded Model Checking of CTL

    Institute of Scientific and Technical Information of China (English)

    Zhi-Hong Tao; Cong-Hua Zhou; Zhong Chen; Li-Fu Wang

    2007-01-01

    Bounded Model Checking has been recently introduced as an efficient verification method for reactive systems.This technique reduces model checking of linear temporal logic to propositional satisfiability.In this paper we first present how quantified Boolean decision procedures can replace BDDs.We introduce a bounded model checking procedure for temporal logic CTL* which reduces model checking to the satisfiability of quantified Boolean formulas.Our new technique avoids the space blow up of BDDs, and extends the concept of bounded model checking.

  19. 14 CFR 91.1093 - Initial and transition training and checking: Check pilots (aircraft), check pilots (simulator).

    Science.gov (United States)

    2010-01-01

    ... checking: Check pilots (aircraft), check pilots (simulator). 91.1093 Section 91.1093 Aeronautics and Space....1093 Initial and transition training and checking: Check pilots (aircraft), check pilots (simulator... observation check may be accomplished in part or in full in an aircraft, in a flight simulator, or in a...

  20. Checking Security Policy Compliance

    CERN Document Server

    Gowadia, Vaibhav; Kudo, Michiharu

    2008-01-01

    Ensuring compliance of organizations to federal regulations is a growing concern. This paper presents a framework and methods to verify whether an implemented low-level security policy is compliant to a high-level security policy. Our compliance checking framework is based on organizational and security metadata to support refinement of high-level concepts to implementation specific instances. Our work uses the results of refinement calculus to express valid refinement patterns and their properties. Intuitively, a low-level security policy is compliant to a high-level security policy if there is a valid refinement path from the high-level security policy to the low-level security policy. Our model is capable of detecting violations of security policies, failures to meet obligations, and capability and modal conflicts.

  1. Flow characteristics and performance evaluation of butterfly valves using numerical analysis

    International Nuclear Information System (INIS)

    The industrial butterfly valves have been applied to various fields that transport fluid in volume, especially water supply and drainage pipeline for flow control. The butterfly valves in various shapes are manufactured, but a fitting performance comparison is not made up. For this reason, we carried out numerical analysis of some kind of butterfly valves for water supply and drainage pipeline using commercial CFD code FLUENT, and made a comparative study of these results. Also, the flow coefficient, the loss coefficient, and pressure distribution of valves according to valve opening rate were compared each other and the influence of these design variables on valve performance were checked over. Through flow around the valve disk, such as pressure distribution, flow pattern, velocity vectors, and form of vortex, we grasped flow characteristics.

  2. Force Augmentation for Relief Valve

    Science.gov (United States)

    Luger, J.

    1982-01-01

    Simple design change for poppet relief valve enables flow through valve to exert additional force to help keep valve open. Although originally intended for relief valves for liquid oxygen and liquid nitrogen in Space Shuttle orbiter, concept is applicable to pressure-or flow-actuated valves for wide range of fluids and temperatures.

  3. A computer code for seismic qualification of nuclear service valves

    International Nuclear Information System (INIS)

    The computer code, CERTIVALVE, has been developed for detailed frequency, seismic stress, and deformation analysis of nuclear service valves. It is an expedient means of analyzing, designing, and qualifying nuclear service valves for dynamic loads. The program is designed to be applicable to virtually all types of ASME Class 1, 2, and 3 valves, including gate, globe, disk, ball, safety-relief, diaphragm, and butterfly valves. It can evaluate valves of nearly all major manufacturers both foreign and domestic. CERTIVALVE computes all natural frequencies of any valve up to 40 Hertz (or higher if the user desires). The program constructs a multi-degree-offreedom (MDOF) finite element model which is used in the eigenvalue (natural frequency) solution. CERTIVALVE also computes the maximum allowable acceleration capacity of any valve on the basis of user-supplied allowable stress limits and the geometric and material properties of the valve components. The worst spatial orientation of the valve is assumed. The maximum allowable resultant is reported in terms of a multiple of weight (that is, in values of g) for each valve component. The valve components evaluated include the non-pressure retaining yoke structure for prismatic, nonprismatic, and curved sections; the yoke-bonnet junction for bolted, clamped and bossed connection details; the bonnet and body sections for various geometric cross sections; and the body-bonnet junction for both bolted-gasket and threaded connections. Finally, the program also performs an operability deformation analysis to check that stem binding is precluded. The evaluation procedures are performed in accordance with included codes and standards. The theoretical development of the program is provided and examples of the program options are presented

  4. Automatic rotary valve actuator

    International Nuclear Information System (INIS)

    This report describes the design, construction, and operation of a microcomputer-controlled valve actuator for operating test valves requiring rotary motion of the valve stem. An AIM 65 microcomputer, using a FORTH language program, controls an air motor and air clutch mounted within an oven to accomplish testing at elevated temperatures. The valve actuator closes the test valve until a preset torque is reached and then opens the valve to its initial starting point. The number of cycles and extremes of rotation are tallied and printed as the test progresses. Provisions are made to accept remote signals to stop the test and to indicate to a remote device when the test has been stopped

  5. JenaValve.

    Science.gov (United States)

    Treede, Hendrik; Rastan, Ardawan; Ferrari, Markus; Ensminger, Stephan; Figulla, Hans-Reiner; Mohr, Friedrich-Wilhelm

    2012-09-01

    The JenaValve is a next-generation TAVI device which consists of a well-proven porcine root valve mounted on a low-profile nitinol stent. Feeler guided positioning and clip fixation on the diseased leaflets allow for anatomically correct implantation of the device without rapid pacing. Safety and efficacy of transapical aortic valve implantation using the JenaValve were evaluated in a multicentre prospective study that showed good short and midterm results. The valve was CE-mark released in Europe in September 2011. A post-market registry ensures on-going and prospective data collection in "real-world" patients. The transfemoral JenaValve delivery system will be evaluated in a first-in-man study in the near future. PMID:22995119

  6. Low noise control valve

    International Nuclear Information System (INIS)

    Noise is one of the problems associated with the use of any type of control valve in systems involving the flow of fluids. The advent of OSHA standards has prompted control valve manufacturers to design valves with special trim to lower the sound pressure level to meet these standards. However, these levels are in some cases too high, particularly when a valve must be located in or near an area where people are working at tasks requiring a high degree of concentration. Such locations are found around and near research devices and in laboratory-office areas. This paper describes a type of fluid control device presently being used at PPL as a bypass control valve in deionized water systems and designed to reduce sound pressure levels considerably below OSHA standards. Details of the design and construction of this constant pressure drop variable flow control valve are contained in the text and are shown in photographs and drawings. Test data taken are included

  7. Dual valve plate two-way pressure relief valve

    Science.gov (United States)

    Angeli, Robert J.

    1994-02-01

    There is disclosed a two-way valve which includes dual valve plates to be positioned between first and second chambers having varying pressure therein, to relieve excess pressure in either chamber by permitting fluid flow from one chamber to the other. The valve includes a body portion having disposed therein dual valve plates. In the equilibrium state, the first valve plate is spring biased against the valve body in the direction of the first chamber to seal off any flow through the valve. The second valve plate is separately spring biased against the first valve plate in the direction of the second chamber, scaling off flow between the valve plates. When the pressure of the first chamber is greater than the pressure of the second chamber by a pre-determined amount, the first and second valve plates move away from the valve body permitting fluid flow from the first chamber to the second chamber.

  8. [Modern mitral valve surgery].

    Science.gov (United States)

    Bothe, W; Beyersdorf, F

    2016-04-01

    At the beginning of the 20th century, Cutler and Levine performed the first successful surgical treatment of a stenotic mitral valve, which was the only treatable heart valve defect at that time. Mitral valve surgery has evolved significantly since then. The introduction of the heart-lung machine in 1954 not only reduced the surgical risk, but also allowed the treatment of different mitral valve pathologies. Nowadays, mitral valve insufficiency has become the most common underlying pathomechanism of mitral valve disease and can be classified into primary and secondary mitral insufficiency. Primary mitral valve insufficiency is mainly caused by alterations of the valve (leaflets and primary order chords) itself, whereas left ventricular dilatation leading to papillary muscle displacement and leaflet tethering via second order chords is the main underlying pathomechanism for secondary mitral valve regurgitation. Valve reconstruction using the "loop technique" plus annuloplasty is the surgical strategy of choice and normalizes life expectancy in patients with primary mitral regurgitation. In patients with secondary mitral regurgitation, implanting an annuloplasty is not superior to valve replacement and results in high rates of valve re-insufficiency (up to 30 % after 3 months) due to ongoing ventricular dilatation. In order to improve repair results in these patients, we add a novel subvalvular technique (ring-noose-string) to the annuloplasty that aims to prevent ongoing ventricular remodeling and re-insufficiency. In modern mitral surgery, a right lateral thoracotomy is the approach of choice with excellent repair and cosmetic results. PMID:26907868

  9. Diagnostic for two-mode variable valve activation device

    Science.gov (United States)

    Fedewa, Andrew M

    2014-01-07

    A method is provided for diagnosing a multi-mode valve train device which selectively provides high lift and low lift to a combustion valve of an internal combustion engine having a camshaft phaser actuated by an electric motor. The method includes applying a variable electric current to the electric motor to achieve a desired camshaft phaser operational mode and commanding the multi-mode valve train device to a desired valve train device operational mode selected from a high lift mode and a low lift mode. The method also includes monitoring the variable electric current and calculating a first characteristic of the parameter. The method also includes comparing the calculated first characteristic against a predetermined value of the first characteristic measured when the multi-mode valve train device is known to be in the desired valve train device operational mode.

  10. Heimlich valve and pneumothorax

    OpenAIRE

    Gogakos, Apostolos; Barbetakis, Nikolaos; Lazaridis, George; Papaiwannou, Antonis; Karavergou, Anastasia; Lampaki, Sofia; Baka, Sofia; Mpoukovinas, Ioannis; Karavasilis, Vasilis; Kioumis, Ioannis; Pitsiou, Georgia; Katsikogiannis, Nikolaos; Tsakiridis, Kosmas; Rapti, Aggeliki; Trakada, Georgia

    2015-01-01

    The Heimlich valve is a small one-way valve used for chest drainage that empties into a flexible collection device and prevents return of gases or fluids into the pleural space. The Heimlich valve is less than 13 cm (5 inches) long and facilitates patient ambulation. Currently there are several systems in the market. It can be used in many patients instead of a traditional water seal drainage system. The Heimlich chest drainage valve was developed so that the process of draining the pleural c...

  11. Butterfly valves for seawater

    International Nuclear Information System (INIS)

    Recently in thermal and nuclear power stations and chemical plants which have become large capacity, large quantity of cooling water is required, and mostly seawater is utilized. In these cooling water systems, considering thermal efficiency and economy, the pipings become complex, and various control functions are demanded. For the purpose, the installation of shut-off valves and control valves for pipings is necessary. The various types of valves have been employed, and in particular, butterfly valves have many merits in their function, size, structure, operation, maintenance, usable period, price and so on. The corrosion behavior of seawater is complicated due to the pollution of seawater, therefore, the environment of the valves used for seawater became severe. The structure and the features of the butterfly valves for seawater, the change of the structure of the butterfly valves for seawater and the checkup of the butterfly valves for seawater are reported. The corrosion of metallic materials is complicatedly different due to the locating condition of plants, the state of pipings and the condition of use. The corrosion countermeasures for butterfly valves must be examined from the synthetic viewpoints. (K.I.)

  12. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... the primary reason that we end up offering patients aortic valve surgery in our community. Aortic stenosis ... a picture of the aortic valve from a patient who had a very diseased aortic valve. And ...

  13. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... opens freely when the heart contracts. On the right, we see a picture of the aortic valve ... the aortic valve because the probe is sitting right behind the aortic valve. Lots of patients on ...

  14. 14 CFR 135.339 - Initial and transition training and checking: Check airmen (aircraft), check airmen (simulator).

    Science.gov (United States)

    2010-01-01

    ... checking: Check airmen (aircraft), check airmen (simulator). 135.339 Section 135.339 Aeronautics and Space... and checking: Check airmen (aircraft), check airmen (simulator). (a) No certificate holder may use a... an aircraft, in a flight simulator, or in a flight training device. This paragraph applies...

  15. Unidirectional valve malfunction by the breakage or malposition of disc - two cases report -

    OpenAIRE

    Lee, Chol; Lee, Kyu Chang; Kim, Hye Young; Kim, Mi Na; Choi, Eun Kyung; Kim, Ji-Sub; Lee, Won Sang; Lee, Myeong Jong; Kim, Hyung Tae

    2013-01-01

    Malfunction of the unidirectional valve in a breathing circuit system may cause hypercapnia from the rebreathing of expired gas, ventilation failure, and barotrauma. Capnography is a useful method for monitoring the integrity of the unidirectional valve. We experienced two cases of malfunction of a unidirectional valve which caused leakage and reverse flow, diagnosed early as a change of the capnographic waveform. One case was caused by expiratory unidirectional valve breakage. The other was ...

  16. 3-D Transient CFD Model For A Rolling Piston Compressor With A Dynamic Reed Valve

    OpenAIRE

    Ding, Hui; Gao, Haiyang

    2014-01-01

    Rolling pistons are widely used as compressors in air conditioning systems due to their small size, low cost, and high performance. Reed valves, a special type of check valve driven by hydraulic forces, are commonly used with many types of compressors to restrict the flow to one direction. Reed valves are typically made of a thin layer of metal or plastic materials. The valve will bend in response to fluid pressure forces to open up the flow channel at the proper moment within the compression...

  17. Heimlich valve and pneumothorax.

    Science.gov (United States)

    Gogakos, Apostolos; Barbetakis, Nikolaos; Lazaridis, George; Papaiwannou, Antonis; Karavergou, Anastasia; Lampaki, Sofia; Baka, Sofia; Mpoukovinas, Ioannis; Karavasilis, Vasilis; Kioumis, Ioannis; Pitsiou, Georgia; Katsikogiannis, Nikolaos; Tsakiridis, Kosmas; Rapti, Aggeliki; Trakada, Georgia; Zissimopoulos, Athanasios; Tsirgogianni, Katerina; Zarogoulidis, Konstantinos; Zarogoulidis, Paul

    2015-03-01

    The Heimlich valve is a small one-way valve used for chest drainage that empties into a flexible collection device and prevents return of gases or fluids into the pleural space. The Heimlich valve is less than 13 cm (5 inches) long and facilitates patient ambulation. Currently there are several systems in the market. It can be used in many patients instead of a traditional water seal drainage system. The Heimlich chest drainage valve was developed so that the process of draining the pleural cavity could be accomplished in a safe, relatively simple, and efficient manner. This valve system has replaced the cumbersome underwater drainage bottle system. Moreover; the Heimlich valve system connects to chest tubing and allows fluid and air to pass in one direction only. This system functions in any position, and it does not ever need to be clamped, a regulated suction can be attached to it if necessary. The valve drains into a plastic bag that can be held at any level, allowing the patient undergoing chest drainage to be ambulatory simply by carrying the bag. In the current mini review we will present the Heimlich valve system and method of insertion. PMID:25861609

  18. Compositional and Quantitative Model Checking

    DEFF Research Database (Denmark)

    Larsen, Kim Guldstrand

    This paper gives a survey of a composition model checking methodology and its succesfull instantiation to the model checking of networks of finite-state, timed, hybrid and probabilistic systems with respect; to suitable quantitative versions of the modal mu-calculus [Koz82]. The method is based on...

  19. Model Checking as Static Analysis

    DEFF Research Database (Denmark)

    Zhang, Fuyuan

    properties which can predict safe approximations to program behaviors. In this thesis, we have developed several static analysis based techniques to solve model checking problems, aiming at showing the link between static analysis and model checking. We focus on logical approaches to static analysis......Both model checking and static analysis are prominent approaches to detecting software errors. Model Checking is a successful formal method for verifying properties specified in temporal logics with respect to transition systems. Static analysis is also a powerful method for validating program...... multi-valued setting, and we therefore obtain a multivalued analysis for temporal properties specied by CTL formulas. In particular, we have shown that the three-valued CTL model checking problem over Kripke modal transition systems can be exactly encoded in three-valued ALFP. Last, we come back to two...

  20. Statistical Model Checking of Rich Models and Properties

    DEFF Research Database (Denmark)

    Poulsen, Danny Bøgsted

    undecidability issues for the traditional model checking approaches. Statistical model checking has proven itself a valuable supplement to model checking and this thesis is concerned with extending this software validation technique to stochastic hybrid systems. The thesis consists of two parts: the first part...... motivates why existing model checking technology should be supplemented by new techniques. It also contains a brief introduction to probability theory and concepts covered by the six papers making up the second part. The first two papers are concerned with developing online monitoring techniques for...... systems. The fifth paper shows how stochastic hybrid automata are useful for modelling biological systems and the final paper is concerned with showing how statistical model checking is efficiently distributed. In parallel with developing the theory contained in the papers, a substantial part of this work...

  1. Multimodality Imaging of Heart Valve Disease

    Energy Technology Data Exchange (ETDEWEB)

    Rajani, Ronak, E-mail: Dr.R.Rajani@gmail.com [Department of Cardiology, St. Thomas’ Hospital, London (United Kingdom); Khattar, Rajdeep [Department of Cardiology, Royal Brompton Hospital, London (United Kingdom); Chiribiri, Amedeo [Divisions of Imaging Sciences, The Rayne Institute, St. Thomas' Hospital, London (United Kingdom); Victor, Kelly; Chambers, John [Department of Cardiology, St. Thomas’ Hospital, London (United Kingdom)

    2014-09-15

    Unidentified heart valve disease is associated with a significant morbidity and mortality. It has therefore become important to accurately identify, assess and monitor patients with this condition in order that appropriate and timely intervention can occur. Although echocardiography has emerged as the predominant imaging modality for this purpose, recent advances in cardiac magnetic resonance and cardiac computed tomography indicate that they may have an important contribution to make. The current review describes the assessment of regurgitant and stenotic heart valves by multimodality imaging (echocardiography, cardiac computed tomography and cardiac magnetic resonance) and discusses their relative strengths and weaknesses.

  2. Evaluation of mitral valve replacement anchoring in a phantom

    Science.gov (United States)

    McLeod, A. Jonathan; Moore, John; Lang, Pencilla; Bainbridge, Dan; Campbell, Gordon; Jones, Doug L.; Guiraudon, Gerard M.; Peters, Terry M.

    2012-02-01

    Conventional mitral valve replacement requires a median sternotomy and cardio-pulmonary bypass with aortic crossclamping and is associated with significant mortality and morbidity which could be reduced by performing the procedure off-pump. Replacing the mitral valve in the closed, off-pump, beating heart requires extensive development and validation of surgical and imaging techniques. Image guidance systems and surgical access for off-pump mitral valve replacement have been previously developed, allowing the prosthetic valve to be safely introduced into the left atrium and inserted into the mitral annulus. The major remaining challenge is to design a method of securely anchoring the prosthetic valve inside the beating heart. The development of anchoring techniques has been hampered by the expense and difficulty in conducting large animal studies. In this paper, we demonstrate how prosthetic valve anchoring may be evaluated in a dynamic phantom. The phantom provides a consistent testing environment where pressure measurements and Doppler ultrasound can be used to monitor and assess the valve anchoring procedures, detecting pararvalvular leak when valve anchoring is inadequate. Minimally invasive anchoring techniques may be directly compared to the current gold standard of valves sutured under direct vision, providing a useful tool for the validation of new surgical instruments.

  3. Gate valve performance prediction

    International Nuclear Information System (INIS)

    The Electric Power Research Institute is carrying out a program to improve the performance prediction methods for motor-operated valves. As part of this program, an analytical method to predict the stem thrust required to stroke a gate valve has been developed and has been assessed against data from gate valve tests. The method accounts for the loads applied to the disc by fluid flow and for the detailed mechanical interaction of the stem, disc, guides, and seats. To support development of the method, two separate-effects test programs were carried out. One test program determined friction coefficients for contacts between gate valve parts by using material specimens in controlled environments. The other test program investigated the interaction of the stem, disc, guides, and seat using a special fixture with full-sized gate valve parts. The method has been assessed against flow-loop and in-plant test data. These tests include valve sizes from 3 to 18 in. and cover a considerable range of flow, temperature, and differential pressure. Stem thrust predictions for the method bound measured results. In some cases, the bounding predictions are substantially higher than the stem loads required for valve operation, as a result of the bounding nature of the friction coefficients in the method

  4. Scram system with continuos check

    International Nuclear Information System (INIS)

    The equipment described pretends to be a further step to the use of integrated circuits in nuclear instrumentation, considering that this type of control was traditionally carried out on the bases of electromechanical elements. A continuous self-check method has been applied in accordance with the high reliability requiered for this type of equipments. The developed equipment fulfils the condition that any deficiency in its component elements, causes an anormal self-detected operation. The equipment covers two systems: the Scram one, that includes the sequence generator-detector, the rods check and scram chain, and the Check system that uses pulses from the sequence detector. (author)

  5. New methods of concurrent checking

    CERN Document Server

    Goessel, Michael; Sogomonyan, Egor; Marienfeld, Daniel

    2008-01-01

    Written by a team of two leading experts and two very successful young former PhD students, New Methods of Concurrent Checking describes new methods of concurrent checking, such as partial duplication, use of output dependencies, complementary circuits, self-dual parity, self-dual duplication and others. A special chapter demonstrates how the new general methods of concurrent checking can be more specifically applied to regular structures to obtain optimum results. This is exemplified for all types of adders up to 64 bits with a level of detail never before presented in the literature. The cle

  6. Diseases of the Tricuspid Valve

    Science.gov (United States)

    ... Myocarditis Obstructive Sleep Apnea Pericarditis Peripheral Vascular Disease Rheumatic Fever Sick Sinus Syndrome Silent Ischemia Stroke Sudden Cardiac Arrest Valve Disease Vulnerable Plaque Diseases of the Tricuspid Valve | Share Diseases of the heart valves are grouped according to which valve or ...

  7. Transcatheter CoreValve valve-in-valve implantation in a stentless porcine aortic valve for severe aortic regurgitation

    OpenAIRE

    Yong, Celina M; Buchbinder, Maurice; Giacomini, John C

    2014-01-01

    Key Clinical Message We describe the first valve-in-valve Corevalve transcatheter aortic valve replacement in the St. Jude Toronto stentless porcine aortic valve in the United States, which enabled this 59-year-old patient with a history of bacterial endocarditis and aortic regurgitation to avoid heart transplant with complete resolution of his severe left ventricular dysfunction.

  8. GIANT PROSTHETIC VALVE THROMBUS

    Directory of Open Access Journals (Sweden)

    Prashanth Kumar

    2015-04-01

    Full Text Available Mechanical prosthetic valves are predisposed to bleeding, thrombosis & thromboembolic complications. Overall incidence of thromboembolic complications is 1% per year who are on oral anticoagulants, whereas bleeding complications incidence is 0.5% to 6.6% per year. 1, 2 Minimization of Scylla of thromboembolic & Charybdis of bleeding complication needs a balancing act of optimal antithrombotic therapy. We are reporting a case of middle aged male patient with prosthetic mitral valve presenting in heart failure. Patient had discontinued anticoagulants, as he had subdural hematoma in the past. He presented to our institute with a giant prosthetic valve thrombus.

  9. Model Checking Algorithms for CTMDPs

    DEFF Research Database (Denmark)

    Buchholz, Peter; Hahn, Ernst Moritz; Hermanns, Holger;

    2011-01-01

    Continuous Stochastic Logic (CSL) can be interpreted over continuoustime Markov decision processes (CTMDPs) to specify quantitative properties of stochastic systems that allow some external control. Model checking CSL formulae over CTMDPs requires then the computation of optimal control strategie...

  10. Treasury Check Verification Query (TCVQ)

    Data.gov (United States)

    Social Security Administration — The TCVQ system determines the SSN of an individual whose check has been returned to a local field office. The FO is able to request this information via the TCVQ...

  11. Advances in Probabilistic Model Checking

    OpenAIRE

    Kwiatkowska, Marta; Parker, David

    2012-01-01

    Probabilistic model checking is an automated verification method that aims to establish the correctness of probabilistic systems. Probability may arise, for example, due to failures of unreliable components, communication across lossy media, or through the use of randomisation in distributed protocols. Probabilistic model checking enables a range of exhaustive, quantitative analyses of properties such as "the probability of a message being delivered within 5ms is at least 0.89". In the last t...

  12. Model checking PSL safety properties

    OpenAIRE

    Launiainen, Tuomas

    2009-01-01

    Model checking is a modern, efficient approach to gaining confidence of the correctness of complex systems. It outperforms conventional testing methods especially in cases where a high degree of confidence in the correctness of the system is required, or when the test runs of the system are difficult to reproduce accurately. In model checking the system is verified against a specification that is expressed in a formal specification language. The main challenges are that the process requires q...

  13. Community perspectives: Community check cashing

    OpenAIRE

    Daniel Leibsohn

    2011-01-01

    In May of 2009, Community Development Finance (CDF) opened the first nonprofit, full-service check cashing store in the country in Fruitvale, California. The project is designed to provide low-income households with the financial services they need, without the asset-stripping characteristics common to the fringe banking industry. In addition to providing affordable check cashing services and a payday loan product, CDF also provides financial coaching and literacy training, small business ass...

  14. Model composition in model checking

    OpenAIRE

    Felscher, Ingo

    2014-01-01

    Model-checking allows one to formally check properties of systems: these properties are modeled as logic formulas and the systems as structures like transition systems. These transition systems are often composed, i.e., they arise in form of products or sums. The composition technique allows us to deduce the truth of a formula in the composed system from "interface information": the truth of formulas for the component systems and information in which components which of these formulas hold. W...

  15. Body checking behaviors in men

    OpenAIRE

    Walker, D. Catherine; Anderson, Drew A.; Hildebrandt, Thomas

    2009-01-01

    Males have been facing increasing pressure from the media to attain a lean, muscular physique, and are at risk for body dissatisfaction, disturbed eating and exercise behaviors, and abuse of appearance- and performance-enhancing drugs (APEDs). The aim of the current study was to examine the relationship between body checking and mood, symptoms of muscle dysmorphia, importance of shape and weight, and APED use in undergraduate males. Body checking in males was correlated with weight and shape ...

  16. Minimising life cycle costs of automated valves in offshore platforms

    Energy Technology Data Exchange (ETDEWEB)

    Yli-Petays, Juha [Metso Automation do Brasil Ltda., Rio de Janeiro, RJ (Brazil); Niemela, Ismo [Metso Automation, Imatra (Finland)

    2012-07-01

    Automated process valves play an essential role in offshore platforms operation. If you are able to optimize their operation and maintenance activities you can receive extensive operational savings with minimal investment. Valves used in offshore platforms doesn't differentiate that much from the valves used in downstream but there are certain specialties, which makes the operations more challenging in offshore: Process valves are more difficult to access and maintain because of space limitations. Also spare part inventories and deliveries are challenging because of offshore platform's remote location. To overcome these challenges usage of digital positioners with diagnostic features has become more common because predictive maintenance capabilities enable possibilities to plan the maintenance activities and this way optimise the spare part orders regarding to valves. There are intelligent controllers available for control valves, automated on/off valves as well as ESD-valves and whole network of automated valves on platforms can be controlled by intelligent valve controllers. This creates many new opportunities in regards of optimized process performance or predictive maintenance point-of-view. By means of intelligent valve controllers and predictive diagnostics, condition monitoring and maintenance planning can also be performed remotely from an onshore location. Thus, intelligent valve controllers provide good way to minimize spending related to total cost of ownership of automated process valves. When purchase value of control valve represent 20% of TCO, intelligent positioner and predictive maintenance methods can enable as high as 30% savings over the life cycle of asset so basically it benefit savings higher than whole investment of monitored asset over its life cycle. This is mainly achieved through the optimized maintenance activities since real life examples has shown that with time based maintenance (preventive maintenance) approach 70% of

  17. Dry product valve

    International Nuclear Information System (INIS)

    This invention provides a system for delivering particulate radioactive or other toxic wastes to a container in which they can be solidified. The system includes a set of valves that prevent the escape of dusty materials to the atmosphere

  18. Mitral valve regurgitation

    Science.gov (United States)

    ... MVP) Rare conditions, such as untreated syphilis or Marfan syndrome Rheumatic heart disease. This is a complication ... the arteries Heart failure - overview High blood pressure Marfan syndrome Mitral valve prolapse Pulmonary embolus Stroke Update ...

  19. Mitral valve regurgitation

    Science.gov (United States)

    ... valve prolapse (MVP) Rare conditions, such as untreated syphilis or Marfan syndrome Rheumatic heart disease. This is ... P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine . 9th ed. Philadelphia, PA: Elsevier Saunders; 2011: ...

  20. Early postpartum mitral valve thrombosis requiring extra corporeal membrane oxygenation before successful valve replacement.

    Science.gov (United States)

    Halldorsdottir, H; Nordström, J; Brattström, O; Sennström, M M; Sartipy, U; Mattsson, E

    2016-05-01

    Pregnancy is associated with an increased risk of thrombosis in women with mechanical prosthetic heart valves. We present the case of a 29-year-old woman who developed early postpartum mitral valve thrombus after an elective cesarean delivery. The patient had a mechanical mitral valve and was treated with warfarin in the second trimester, which was replaced with high-dose dalteparin during late pregnancy. Elective cesarean delivery was performed under general anesthesia at 37weeks of gestation. The patient was admitted to the intensive care unit for postoperative care and within 30min she developed dyspnea and hypoxia requiring mechanical ventilation. She deteriorated rapidly and developed pulmonary edema, worsening hypoxia and severe acidosis. Urgent extra corporeal membrane oxygenation was initiated. Transesophageal echocardiography revealed a mitral valve thrombus. The patient underwent a successful mitral valve replacement after three days on extra corporeal membrane oxygenation. This case highlights the importance of multidisciplinary care and frequent monitoring of anticoagulation during care of pregnant women with prosthetic heart valves. PMID:26775895

  1. When a Mechanical Valve Goes Freestyle: A Patient Tailored Valve-In-Valve Implantation.

    Science.gov (United States)

    François, J; Cathenis, K; Hamerlijnck, R

    2015-01-01

    In case of a redo operation after a full root replacement there are two possible options: replacing the entire root or performing a more conservative valve-in-valve implantation. Regarding the relatively high morbidity and mortality of a redo root replacement, the valve-in-valve implantation is the preferred choice if technically feasible. We present the case of a valve-in-valve implantation with a St. Jude mechanical valve in a Medtronic bioprosthesis in a 57-year old man. Follow-up echocardiography after 1 month showed a mean gradient of 17 mmHg and no paravalvular leakage. The combination of a St. Jude bileaflet mechanical valve implanted in a Freestyle root prosthesis has not been described. This case shows that patient tailored treatment with a St. Jude bileaflet mechanical valve in a Freestyle aortic root valve can be safely performed and might be the preferred choice for younger patients, if technically feasible. PMID:26560005

  2. Aortic valve replacement

    DEFF Research Database (Denmark)

    Kapetanakis, Emmanouil I; Athanasiou, Thanos; Mestres, Carlos A;

    2008-01-01

    BACKGROUND AND AIMS OF THE STUDY: Prompted by anecdotal evidence and observations by surgeons, an investigation was undertaken into the potential differences in implanted aortic valve prosthesis sizes, during aortic valve replacement (AVR) procedures, between northern and southern European countr...... southern European countries. Imbalances in the prevalence of rheumatic heart disease, health resource availability and variations in surgical practice throughout Europe might be possible etiological causes....

  3. Condition Monitoring Through Advanced Sensor and Computational Technology

    International Nuclear Information System (INIS)

    The overall goal of this joint research project was to develop and demonstrate advanced sensors and computational technology for continuous monitoring of the condition of components, structures, and systems in advanced and next-generation nuclear power plants (NPPs). This project included investigating and adapting several advanced sensor technologies from Korean and US national laboratory research communities, some of which were developed and applied in non-nuclear industries. The project team investigated and developed sophisticated signal processing, noise reduction, and pattern recognition techniques and algorithms. The researchers installed sensors and conducted condition monitoring tests on two test loops, a check valve (an active component) and a piping elbow (a passive component), to demonstrate the feasibility of using advanced sensors and computational technology to achieve the project goal. Acoustic emission (AE) devices, optical fiber sensors, accelerometers, and ultrasonic transducers (UTs) were used to detect mechanical vibratory response of check valve and piping elbow in normal and degraded configurations. Chemical sensors were also installed to monitor the water chemistry in the piping elbow test loop. Analysis results of processed sensor data indicate that it is feasible to differentiate between the normal and degraded (with selected degradation mechanisms) configurations of these two components from the acquired sensor signals, but it is questionable that these methods can reliably identify the level and type of degradation. Additional research and development efforts are needed to refine the differentiation techniques and to reduce the level of uncertainties

  4. Motor operated valve signatures events extraction module using an specialist system for the nuclear power plant MOV diagnostic system

    International Nuclear Information System (INIS)

    A predictive maintenance program for motor-operated valves is performed every year at Angra I Nuclear Power Plant in order to detect early failures of the valves and to diagnosis the valve degradation. The purpose of this maintenance program is to increase the reactor reliability and security. The main predictive maintenance activities are usually performed in the swing check-valves, gate valves and globe valves. The valves data analysis usually performed during the plant outage allows one to detect any failure and adjust the valves parameters like torque-switch and limitorque. The main purpose of this thesis is to develop a computer program to select the valve events parameter using the valve power signature during the closed-open and open-closed cycles. The results obtained by the developed algorithm are connected to a developed specialist system to perform the valves events identification. An important contribution of this thesis is that the valves signature features are obtained without changing the signal morphology. (author)

  5. Factors affecting the valve movements in freshwater unionids

    Energy Technology Data Exchange (ETDEWEB)

    Pynnoenen, K.S.; Englund, V.P.M. [Univ. of Helsinki (Finland)

    1994-12-31

    In order to avoid harmful conditions, freshwater unionids are able to close their valves and to resist extended long periods of complete anoxia. Xenobiotics and diverse abiotic and biotic factors can change the rhythm of valve movements and thus affect the accumulation of heavy metals in these bivalves. When bivalves are used a bioindicators in the field and when the accumulation of toxicants are studied under the laboratory conditions, the effects of valve movements and shell closure have to be involved. In this study, the authors have recorded valve movements of two different unionid species (Anodonta anatina, Unio tumidus) in the field and in the laboratory using a digital monitoring system. Several experimental arrangements were compared (caged mussels vs. sediment dwelling mussels, flow-through vials vs. static aquaria with and without sediment). Some parameters of the mussel hemolymph, such as electrolytes, gases and acid base status, were compared with the results on the valve activity (time with valves open, number of adductions). The natural valve activity of the two unionid species differed clearly. In the field, effects of transfer and caging were found, and in the laboratory, sediment and water flow changed their behavior. The level of the blood oxygen was most affected, whereas, the acid-base status and the concentrations of electrolytes were effectively regulated by the unionids. The correlation between valve movements and the hemolymph parameters was weaker than expected.

  6. Characteristics of electrostatic gas micro-pump with integrated polyimide passive valves

    International Nuclear Information System (INIS)

    We report on the fabrication and characterization of electrostatic gas micro-pumps integrated with polyimide check valves. Touch-mode capacitance actuation, enabled by a fixed silicon electrode and a metal/polyimide diaphragm, creates the suction and push-out of the ambient gas; the gas flow is rectified by the check valves located at the inlet and outlet of the pump. The fabricated pumps were tested with various actuation voltages at different frequencies and duty cycles; an emphasis was placed on investigating the effect of valve flow conductance on the gas pumping characteristics. The pump with higher valve conductance could increase the operating frequency of the pump and affect the pumping characteristics from a pulsating flow to a continuous flow, leading to a higher gas flow rate. This electrostatic pump has a flow control resolution of 1 µL min−1; it could generate a gas flow up to 106 µL min−1. (paper)

  7. Characteristics of electrostatic gas micro-pump with integrated polyimide passive valves

    Science.gov (United States)

    Han, Jeahyeong; Yeom, Junghoon; Mensing, Glennys; Flachsbart, Bruce; Shannon, Mark A.

    2012-09-01

    We report on the fabrication and characterization of electrostatic gas micro-pumps integrated with polyimide check valves. Touch-mode capacitance actuation, enabled by a fixed silicon electrode and a metal/polyimide diaphragm, creates the suction and push-out of the ambient gas; the gas flow is rectified by the check valves located at the inlet and outlet of the pump. The fabricated pumps were tested with various actuation voltages at different frequencies and duty cycles; an emphasis was placed on investigating the effect of valve flow conductance on the gas pumping characteristics. The pump with higher valve conductance could increase the operating frequency of the pump and affect the pumping characteristics from a pulsating flow to a continuous flow, leading to a higher gas flow rate. This electrostatic pump has a flow control resolution of 1 µL min-1 it could generate a gas flow up to 106 µL min-1.

  8. Uncertainty in Cross Orthogonality Checks

    Science.gov (United States)

    Matsumura, Yuichi

    Finite element structural dynamic models are typically validated using data obtained from a modal testing. Although it is known that test variability may affect the verification, the test variability is typically ignored in the verification process. This paper describes the sensitivities of cross orthogonality check to the test variability. The cross orthogonality check is one of correlation techniques which is gaining acceptance in the structural dynamics community, because of its improved accuracy over the standard modal assurance criterion. Then an uncertainty index of the cross orthogonality check is proposed based on the fact that the sensitivities are much dependent on sensor placement. The results of some artificially generated test cases are presented to demonstrate the applicability of the proposed approach.

  9. [Mineralization of heart valves].

    Science.gov (United States)

    Pawlikowski, M; Pfitzner, R

    1992-01-01

    Mineralization (calcification) of heart valves (mitral, aortic and aortic bioprosthesis) have been analyzed using; histology, x-ray diffraction, infrared spectroscopy, scanning microscopy, atomic absorption and electron microprobe. Obtained results showed the presence of two type of mineralization. First type is represented by grains composed of hydroxyapatite containing admixture of carbonates. This mineralization is seen macroscopically. Second type of mineralization is possible to determine only using chemical methods. It is represented by biological structures containing amount of Ca, P and other elements higher then normal heart valves. This second type of the mineralization conducts to the changes of physical features of the tissue. Both types of calcification develops because of the defects of atomic structure of biological components of heart valves (mainly collagen). These defects show the presence of free atomic bindings i.e. electric potential. Because of this, they are able to react with surrounding free joints, starting calcification. Defects of biological structures of heart valves are the results of infections, mechanical destruction of the valves etc. Calcification may be stopped on different stages of its development: or as secret calcification or may pass to the stage seen as apatite grains. PMID:1342999

  10. Emission-free valve

    Energy Technology Data Exchange (ETDEWEB)

    Koppe, W.; Prummer, R.

    1980-07-01

    a description is given of an emission-free valve, particularly a magnetically operated valve, for use in controlling the flow of fluids, especially poisonous, radioactive, aggressive and otherwise dangerous gases and fluids, comprising a housing including a housing member which has substantially spherical configuration and an internal surface surrounding a compartment for the respective fluid, said housing further including an annular valve seat member; a valve member movably mounted in said compartment and cooperating with said valve seat member to control the flow of the fluid through said compartment; and a plating layer of a corrosion-resistant material covering said internal surface of said housing member and also having a substantially spherical configuration corresponding to that of said housing member, said housing member and said plating layer obtaining their respective configurations during an explosion which not only simultaneously deforms initially cylindrical tubular and coaxially arranged housing member and plating layer preforms, but also welds said plating layer preform to said housing member preform so that said platinglayer is explosion-welded to said housing member.

  11. New-onset atrial fibrillation after surgical aortic valve replacement and transcatheter aortic valve implantation: a concise review.

    Science.gov (United States)

    Jørgensen, Troels Højsgaard; Thygesen, Julie Bjerre; Thyregod, Hans Gustav; Svendsen, Jesper Hastrup; Søndergaard, Lars

    2015-01-01

    Surgical aortic valve replacement (SAVR) and, more recently, transcatheter aortic valve implantation (TAVI) have been shown to be the only treatments that can improve the natural cause of severe aortic valve stenosis. However, after SAVR and TAVI, the incidence of new-onset atrial fibrillation (NOAF) is 31%-64% and 4%-32%, respectively. NOAF is independently associated with adverse events such as stroke, death, and increased length of hospital stay. Increasing the knowledge of predisposing factors, optimal postprocedural monitoring, and prophylactic antiarrhythmic and antithrombotic therapy may reduce the risk of complications secondary to NOAF. PMID:25589700

  12. Injection safety valve solutions for CO2 WAG cycle wells

    International Nuclear Information System (INIS)

    Unlike the offshore production industry, there are presently no regulations that dictate the use of subsurface safety valves in land completions. However, due to the increase in the number of fields moving toward CO2 injection as a means of tertiary recovery and the potential for injury or environmental damage, many producers have decided to install subsurface safety valves in their CO2 injection wells. This paper addresses why these wells need to be protected, discuss the parameters that must be considered in the selection of a tubing retrievable safety system and cover the unique features of the following types of safety valves. Surface controlled; Flapper check; Fixed choke-velocity; Variable orifice-velocity; and Pressure differential operated

  13. Research on Valve Body Design of Large Bore Sodium Valve

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Large bore sodium valve is one kind of key equipments of China Demonstration Fast Reactor (CDFR). It is installed in the pipeline before and behind SG units as a locking mechanism. Valve body which is used to bear pressure is the core of sodium valve design.

  14. Huge tricuspid valve abscess.

    Science.gov (United States)

    Manzano Nieto, Carmen M; Vilacosta, Isidre; Corros, Cecilia; Almería, Carlos; Rodríguez, Enrique

    2009-03-01

    A 60-year-old woman with colorectal adenocarcinoma underwent surgical mass resection in 2003; hepatic segmentectomy due to hepatic metastasis was performed in 2005. A port-a-cath for the administration of chemotherapy was cannulated. In April 2007, the patient developed fever and shivering, and the catheter was removed. Catheter and blood cultures were positive for methicillin-sensitive Staphylococcus aureus. TEE showed a very mobile mass (3 x 2 cm) at the junction of the posterior and anterior leaflets of the tricuspid valve. The mass had large echolucent areas inside, exhibiting an appearance like a 'ball of wool' (Panel B). Cardiac MRI confirmed the presence of a mass attached to the tricuspid valve, as shown in the delayed enhancement sequence. At surgery, a ruptured tendinous cord as well as a large abscess within the septal leaflet of the tricuspid valve was found. PMID:19196752

  15. Josephson magnetic rotary valve

    International Nuclear Information System (INIS)

    We propose a control element for a Josephson spin valve. It is a complex Josephson device containing ferromagnetic (F) layer in the weak-link area consisting of two regions, representing 0 and π Josephson junctions, respectively. The valve's state is defined by mutual orientations of the F-layer magnetization vector and boundary line between 0 and π sections of the device. We consider possible implementation of the control element by introduction of a thin normal metal layer in a part of the device area. By means of theoretical simulations, we study properties of the valve's structure as well as its operation, revealing such advantages as simplicity of control, high characteristic frequency, and good legibility of the basic states

  16. Direct Model Checking Matrix Algorithm

    Institute of Scientific and Technical Information of China (English)

    Zhi-Hong Tao; Hans Kleine Büning; Li-Fu Wang

    2006-01-01

    During the last decade, Model Checking has proven its efficacy and power in circuit design, network protocol analysis and bug hunting. Recent research on automatic verification has shown that no single model-checking technique has the edge over all others in all application areas. So, it is very difficult to determine which technique is the most suitable for a given model. It is thus sensible to apply different techniques to the same model. However, this is a very tedious and time-consuming task, for each algorithm uses its own description language. Applying Model Checking in software design and verification has been proved very difficult. Software architectures (SA) are engineering artifacts that provide high-level and abstract descriptions of complex software systems. In this paper a Direct Model Checking (DMC) method based on Kripke Structure and Matrix Algorithm is provided. Combined and integrated with domain specific software architecture description languages (ADLs), DMC can be used for computing consistency and other critical properties.

  17. From preventive to permissive checks

    DEFF Research Database (Denmark)

    Weisdorf, Jacob Louis; Sharp, Paul Richard

    2009-01-01

    The Malthusian "preventive check" mechanism has been well documented for pre-industrial England through evidence for a negative correlation between the marriage rate and the price of wheat. Other literature, however, speculates that the correlation was in fact positive from the early nineteenth...

  18. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... a significant number of mitral valve repairs utilizing robotic techniques as well, which is really outside the ... no significant bleeding. Terry asks if you do robotic valve replacement surgeries. I do not. It's a ...

  19. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... which is made out of pyrolitic carbon, basically metal and plastic. Again, blood flows through this valve. ... has a prosthetic valve should let all their treating physicians, dentists, et cetera, know that so that ...

  20. What Is Heart Valve Disease?

    Science.gov (United States)

    ... heart work harder and affect its ability to pump blood. Overview How the Heart Valves Work At the ... into the atria. As the ventricles contract, they pump blood through the pulmonary and aortic valves. The pulmonary ...

  1. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... several valve companies in this country and in Europe that have designed catheter-based valves that are ... country in the form of trials and in Europe, actually in more liberal form, for more general ...

  2. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... and bovine for cows. Essentially, the tissue from these is harvested from those animals and sewn into ... surface as blood exits through the valve. And these valves are an excellent option. They have great ...

  3. Inexpensive Pressure-Relief Valve

    Science.gov (United States)

    Theordore, E. A.

    1985-01-01

    Simple device vents excess low-pressure gas. Inexpensive pressure relief valve built from polyvinylchloride pipe. Valve suitable for low pressure-- 25 to 50 cm of mercury-- and flow rates up to 14 m3/min.

  4. Transcatheter Aortic Heart Valve Thrombosis

    DEFF Research Database (Denmark)

    Hansson, Nicolaj C; Grove, Erik L; Andersen, Henning R;

    2016-01-01

    BACKGROUND: There is increasing focus on transcatheter heart valve (THV) thrombosis. However, there are limited data on incidence, clinical implications and predisposing factors of THV thrombosis following transcatheter aortic valve replacement (TAVR). OBJECTIVES: We assessed the incidence...

  5. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... of that slide, that demonstrates that patients with New York Heart Association class heart failure 1 and ... right down the aortic valve and that's the new aortic valve that Dr. Streitman's placed. And you ...

  6. Comparative study of Butterfly valves

    International Nuclear Information System (INIS)

    This work tries to justify the hydrodynamic butterfly valves performance, using the EPRI tests, results carried out in laboratory and in situ. This justification will be possible if: - The valves to study are similar - Their performance is calculated using EPRI's methodology Looking for this objective, the elements of the present work are: 1. Brief EPRI butterfly valve description it wild provide the factors which are necessary to define the butterfly valves similarity. 2. EPRI tests description and range of validation against test data definition. 3. Description of the spanish butterfly analyzed valves, and comparison with the EPRI performance results, to prove that this valves are similar to the EPRI test valves. In this way, it will not be necessary to carry out particular dynamic tests on the spanish valves to describe their hydrodynamic performance. (Author)

  7. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... a chronic disease process of inflammation and protein deposition that ultimately results in calcification of the valve. ... heart valve which is made out of pyrolitic carbon, basically metal and plastic. Again, blood flows through ...

  8. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... really, they are two-fold for us to explain to you that, first, there are more significant ... size valve in as possible, as well as making sure that the valve seats appropriately and that ...

  9. Nuclear reactor steam depressurization valve

    International Nuclear Information System (INIS)

    This patent describes improvement in a nuclear reactor plant, an improved steam depressurization valve positioned intermediate along a steam discharge pipe for controlling the venting of steam pressure from the reactor through the pipe. The improvement comprises: a housing including a domed cover forming a chamber and having a partition plate dividing the chamber into a fluid pressure activation compartment and a steam flow control compartment, the valve housing being provided with an inlet connection and an outlet connection in the steam flow control compartment, and a fluid duct in communication with a source of fluid pressure for operating the valve; a valve set mounted within the fluid flow control compartment comprising a cylindrical section surrounding the inlet connection with one end adjoining the connection and having a radially projecting flange at the other end with a contoured extended valve sealing flange provided with an annular valve sealing member, and a valve cylinder traversing the partition plate and reciprocally movable within an opening in the partition plate with one terminal and extending into the fluid pressure activation compartment and the other terminal end extending into the steam flow control compartment coaxially aligned with the valve seat surrounding the inlet connection, the valve cylinder being surrounded by two bellow fluid seals and provided with guides to inhibit lateral movement, an end of the valve cylinder extending into the fluid flow control compartment having a radially projecting flange substantially conterminous with the valve seat flange and having a contoured surface facing and complimentary to the contoured valve seating surface whereby the two contoured valve surfaces can meet in matching relationship, thus providing a pressure actuated reciprocatable valve member for making closing contact with the valve seat and withdrawing therefrom for opening fluid flow through the valve

  10. St Jude Medical Portico valve.

    Science.gov (United States)

    Manoharan, Ganesh; Spence, Mark S; Rodés-Cabau, Joseph; Webb, John G

    2012-09-01

    Transcatheter aortic valve implantation is increasingly being used to treat high-risk patients with symptomatic aortic valve disease. However, challenges still remain with current devices, both in terms of the procedure and the outcome. The St Jude Medical Portico transcatheter valve system is designed to mitigate some of these difficulties. We describe the device characteristics and how the device may impact on a TAVI procedure. An overview of the clinical experiences with the Portico valve system is also described. PMID:22995122

  11. Building valve amplifiers

    CERN Document Server

    Jones, Morgan

    2013-01-01

    Building Valve Amplifiers is a unique hands-on guide for anyone working with tube audio equipment--as an electronics hobbyist, audiophile or audio engineer. This 2nd Edition builds on the success of the first with technology and technique revisions throughout and, significantly, a major new self-build project, worked through step-by-step, which puts into practice the principles and techniques introduced throughout the book. Particular attention has been paid to answering questions commonly asked by newcomers to the world of the valve, whether audio enthusiasts tackling their first build or

  12. Infusion of the solid coal using pressure independent valves to regulate flow

    Energy Technology Data Exchange (ETDEWEB)

    Goretz, H.G.; Betting, K.

    1979-01-01

    In order to improve infusion into the solid coal, attempts were made to effect this through several holes using a single pump; however, the regulation of the quantity of water directed into each hole by a ball-valve tap connected to the injection pump was shown to lack precision - gives the causes of this defect. Satisfactory regulation was obtained by means of pressure- independent flow valves which operate on the principle of hydrodynamic pressure balance; describes method of operation. Underground tests proved satisfactory even with large pressure variations. The problem of dirt penetration during down times was eliminated by installing a check valve. The system proves economical to run.

  13. Telocytes in human heart valves

    Science.gov (United States)

    Yang, Yang; Sun, Wei; Wu, Sean M; Xiao, Junjie; Kong, Xiangqing

    2014-01-01

    Valve interstitial cells (VICs) are responsible for maintaining the structural integrity and dynamic behaviour of the valve. Telocytes (TCs), a peculiar type of interstitial cells, have been recently identified by Popescu*s group in epicardium, myocardium and endocardium (visit http://www.telocytes.com). The presence of TCs has been identified in atria, ventricles and many other tissues and organ, but not yet in heart valves. We used transmission electron microscopy and immunofluorescence methods (double labelling for CD34 and c-kit, or vimentin, or PDGF Receptor-β) to provide evidence for the existence of TCs in human heart valves, including mitral valve, tricuspid valve and aortic valve. TCs are found in both apex and base of heart valves, with a similar density of 27–28 cells/mm2 in mitral valve, tricuspid valve and aortic valve. Since TCs are known for the participation in regeneration or repair biological processes, it remains to be determined how TCs contributes to the valve attempts to re-establish normal structure and function following injury, especially a complex junction was found between TCs and a putative stem (progenitor) cell. PMID:24674389

  14. Cavitation problems in sodium valves

    International Nuclear Information System (INIS)

    Cavitation poses few problems for sodium valves, in spite of the fact that the loops are not pressurized. This is no doubt due to the low flow velocities in the pipes. For auxiliary loop valves we are attempting to standardize performances with respect to cavitation. For economic reasons cavitation thresholds are approached with large diameter valves. (author)

  15. Thermostatic Radiator Valve Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Dentz, J.; Ansanelli, E.

    2015-01-01

    A large stock of multifamily buildings in the Northeast and Midwest are heated by steam distribution systems. Losses from these systems are typically high and a significant number of apartments are overheated much of the time. Thermostatically controlled radiator valves (TRVs) are one potential strategy to combat this problem, but have not been widely accepted by the residential retrofit market.

  16. SAFETY SHUTOFF VALVE

    DEFF Research Database (Denmark)

    2009-01-01

    It is disclosed a shut-off valve which acts automatically and has a fully mechanical performance with respect to the loosing of the tower-shape part balance under the effect of the special acceleration Which is arisen from the quakes waves or serious vibrations, while such vibrations are mainly r...

  17. Vent Relief Valve Test

    Science.gov (United States)

    2008-01-01

    Shown is the disassembly, examination, refurbishment and testing of the LH2 ( liquid hydrogen) and LOX (liquid oxygen) vent and relief valves for the S-IVB-211 engine stage in support of the Constellation/Ares project. This image is extracted from high definition video and is the highest resolution available.

  18. Distortion of the CoreValve during transcatheter aortic valve-in-valve implantation due to valve dislocation

    International Nuclear Information System (INIS)

    Nowadays transcatheter aortic valve implantation (TAVI) is an accepted alternative to surgical aortic valve replacement for high-risk patients (pts). Successful TAVI procedures for failed aortic surgical bioprosthesis (TAV-in-SAV) have already been reported. In the presented two cases of TAV-in-SAV implantation a strut distortion of the stent was revealed on angiographic imaging and confirmed on control CT scan. In both procedures, a dislocation of the medtronic core valve (MCV) prosthesis during implantation led to valve retrieval, with a necessity of reloading it in the 18F introducer before subsequent implantation of the same valve in correct position

  19. Safety and relief valve testing

    International Nuclear Information System (INIS)

    Two major programmes of safety relief valve testing have been established in support of system design and the selection of valves for Sizewell 'B'. The Central Electricity Generating Board has constructed the BRAVO facility to reproduce PWR pressuriser fluid conditions for the full scale testing of pressuriser relief system valves. Current tests on BRAVO, on a full size tandem pair of pressuriser pilot operated safety relief valves, will be followed by the full flow testing of a pressuriser safety valve. Tests at secondary circuit conditions have been carried out at the Siemens Kraftwerk Union Test Facilities, W Germany, where candidate MSSV's have been tested at full scale blowdown conditions. (author)

  20. Distortion of the CoreValve during transcatheter aortic valve-in-valve implantation due to valve dislocation

    Energy Technology Data Exchange (ETDEWEB)

    Souteyrand, Geraud, E-mail: gsouteyrand@chu-clermontferrand.fr [Department of Cardiology, Gabriel Montpied Hospital, CHU Clermont-Ferrand, Clermont-Ferrand (France); ERIM-EA3295, University of Auvergne, Clermont-Ferrand (France); Wilczek, Krzysztof [Department of Cardiology, Medical University of Silesia, Silesian Centre for Herat Diseases, Zabrze (Poland); Innorta, Andrea; Camilleri, Lionel [Department of Cardiology, Gabriel Montpied Hospital, CHU Clermont-Ferrand, Clermont-Ferrand (France); ERIM-EA3295, University of Auvergne, Clermont-Ferrand (France); Chodor, Piotr [Department of Cardiology, Medical University of Silesia, Silesian Centre for Herat Diseases, Zabrze (Poland); Lusson, Jean-René; Motreff, Pascal [Department of Cardiology, Gabriel Montpied Hospital, CHU Clermont-Ferrand, Clermont-Ferrand (France); ERIM-EA3295, University of Auvergne, Clermont-Ferrand (France); Laborde, Jean-Claude [St. George' s Hospital, London (United Kingdom); Chabrot, Pascal; Durel, Nicolas [Department of Cardiology, Gabriel Montpied Hospital, CHU Clermont-Ferrand, Clermont-Ferrand (France); ERIM-EA3295, University of Auvergne, Clermont-Ferrand (France)

    2013-09-15

    Nowadays transcatheter aortic valve implantation (TAVI) is an accepted alternative to surgical aortic valve replacement for high-risk patients (pts). Successful TAVI procedures for failed aortic surgical bioprosthesis (TAV-in-SAV) have already been reported. In the presented two cases of TAV-in-SAV implantation a strut distortion of the stent was revealed on angiographic imaging and confirmed on control CT scan. In both procedures, a dislocation of the medtronic core valve (MCV) prosthesis during implantation led to valve retrieval, with a necessity of reloading it in the 18F introducer before subsequent implantation of the same valve in correct position.

  1. Transaction management with integrity checking

    DEFF Research Database (Denmark)

    Martinenghi, Davide; Christiansen, Henning

    2005-01-01

    Database integrity constraints, understood as logical conditions that must hold for any database state, are not fully supported by current database technology. It is typically up to the database designer and application programmer to enforce integrity via triggers or tests at the application level......, which are difficult to maintain and error prone. Two important aspects must be taken care of. 1.~It is too time consuming to check integrity constraints from scratch after each update, so simplified checks before each update should be used relying on the assumption that the current state is consistent....... 2.~In concurrent database systems, besides the traditional correctness criterion, the execution schedule must ensure that the different transactions can overlap in time without destroying the consistency requirements tested by other, concurrent transactions....

  2. From Preventive to Permissive Checks

    DEFF Research Database (Denmark)

    Sharp, Paul Richard; Weisdorf, Jacob Louis

    The Malthusian "preventive check" mechanism has been well documented for pre-industrial England through evidence for a negativcorrelation between the marriage rate and the price of wheat. Other literature, however, speculates that the correlation was in fact positive from the early nineteenth cen...... shows that this result is not in fact inconsistent with a stylized Malthusian mechanism, and can be understood within the context of an increasing dominance of shocks to aggregate demand rather than to aggregate supply...

  3. Program Analysis as Model Checking

    DEFF Research Database (Denmark)

    Olesen, Mads Chr.

    of an abstract interpretation. For the generalisation to lattice automata to have benefit it is important that efficient tools exist. This thesis presents multi-core tools for efficient and scalable reachability and Büchi emptiness checking of timed/lattice automata. Finally, a number of case studies...... overapproximation of the hardware is needed; the case of identifying timing anomalous hardware for which such abstractions are hard to find is considered....

  4. Checking modes of HAL programs

    OpenAIRE

    de la Banda, MG; Harvey, W; Marriott, K.; Stuckey, PJ; Demoen, Bart

    2005-01-01

    Recent constraint logic programming (CLP) languages, such as HAL and Mercury, require type, mode and determinism declarations for predicates. This information allows the generation of efficient target code and the detection of many errors at compile-time. Unfortunately, mode checking in such languages is difficult. One of the main reasons is that, for each predicate mode declaration, the compiler is required to appropriately re-order literals in the predicate's definition. The task is further...

  5. Measurement of reed valve kinematics

    Directory of Open Access Journals (Sweden)

    Fenkl Michael

    2016-01-01

    Full Text Available The measurement of key kinematic parameters of a reed valve movement is necessary for the further development of the reed valve system. These parameters are dependent on the geometry and material properties of the valve. As they directly affect the quantity of air flowing around the valve, a simple and easy to implement measurement of various valve configuration based on the air flow has been devised and is described in this paper, along with its technical parameters and drawbacks when evaluating reed valves used in reciprocating air compressors. Results are presented for a specimen of a compressor under examination. All kinematic parameters, and timing of the opening and closing of the valve, obtained from the measurement are presented and discussed.

  6. Measurement of reed valve kinematics

    Science.gov (United States)

    Fenkl, Michael; Dvořák, Václav; Vít, Tomáš

    2016-03-01

    The measurement of key kinematic parameters of a reed valve movement is necessary for the further development of the reed valve system. These parameters are dependent on the geometry and material properties of the valve. As they directly affect the quantity of air flowing around the valve, a simple and easy to implement measurement of various valve configuration based on the air flow has been devised and is described in this paper, along with its technical parameters and drawbacks when evaluating reed valves used in reciprocating air compressors. Results are presented for a specimen of a compressor under examination. All kinematic parameters, and timing of the opening and closing of the valve, obtained from the measurement are presented and discussed.

  7. In-operation inspection technology development-4 ''development of degradation prediction technology for motor-operated valves''

    International Nuclear Information System (INIS)

    A method for degradation predicting technology has been proposed for motor operated valves in nuclear power plants which is based on the concept of condition monitoring for maintenance. This method (degradation prediction technology) eliminates the unnecessary overhaul of valves and realizes high reliability and economy. The degradation mechanism was clarified by long time heating experiments of gasket and gland packing and the wear test for them and stem nut to research valve parts degradation by stress (pressure, temperature, etc) during plant operation. Effective electric power measurements for motor operated valves were confirmed to be useful discovering valve part failures. The motor operated valve degradation prediction system was developed on the basis of the experiment results and mechanism. The system is able to predict the degradation of valve parts (gasket/gland packing, stem, stem nut, etc) utilizing plant data (pressure, temperature, etc) and effective power of the motor. The life of valve parts can be estimated from the experimental results. (authors)

  8. Testing of subsea gate valves in sand slurry

    International Nuclear Information System (INIS)

    This paper reports on three gate valves from different manufacturers that have been performance tested in a test loop. Anticipated production rates on the Statfjord Satellite Fields (SSF) have been simulated. The testing was part of the pre-qualification of the Christmas tree valves for this project. The tests were performed in order to determine the expected cycle life and failure mode while operating in a sand slurry environment. The valve's ability to hold gas liquid pressure was monitored throughout the test. On completion of the tests, the valves were disassembled and inspected for wear and tear, and the gates subjected to a material analysis. Information gained from the tests has proved to be very useful for the development of SSF

  9. Developments in mechanical heart valve prosthesis

    Indian Academy of Sciences (India)

    Kalyani Nair; C V Muraleedharan; G S Bhuvaneshwar

    2003-06-01

    Artificial heart valves are engineered devices used for replacing diseased or damaged natural valves of the heart. Most commonly used for replacement are mechanical heart valves and biological valves. This paper briefly outlines the evolution, designs employed, materials being used,. and important factors that affect the performance of mechanical heart valves. The clinical performance of mechanical heart valves is also addressed. Efforts made in India in the development of mechanical heart valves are also discussed.

  10. Monitor

    Data.gov (United States)

    US Agency for International Development — A custom-built, dual-language (English and Spanish) system (http://www.monitor.net.co/) developed by DevTech that debuted in January 2011. It features a central PMP...

  11. Valve actuator motor degradation

    International Nuclear Information System (INIS)

    Valve actuator motor degradation and failure has been a significant, but little studied, problem in the nuclear industry. This study provides a discussion of the primary failure mode --thermal degradation-- and reviews the basis for the solution to thermal degradation -- thermal protection. The study also provides reviews of various industry data bases, discusses effects of other failure modes such as corrosion, and provides a review of other considerations the user should entertain when assessing thermal protection

  12. 25 CFR 141.19 - Check cashing.

    Science.gov (United States)

    2010-04-01

    ... may give a fully negotiable check in addition to U.S. currency when cashing a draft, check or money... or any other obligation the customer owes to the business, but in no event may the owner or...

  13. Checking Out Cuts, Scratches, and Abrasions

    Science.gov (United States)

    ... Skating Crushes What's a Booger? Checking Out Cuts, Scratches, and Abrasions KidsHealth > For Kids > Checking Out Cuts, ... weren't wearing kneepads. How Do Cuts and Scratches Heal? After getting a cut, scratch, or abrasion, ...

  14. Self-checking state machine realizations in CMOS

    Science.gov (United States)

    Lala, P. K.

    1994-06-01

    In this reporting period, we have studied the currently available techniques for designing totally self-check checkers for m-out-of-n codes. Such codes can be used for state assignment in self-checking state machines. The major advantage of m-out-of-n codes is that they can detect single and unidirectional multibit errors in the encoded information bits. Thus, if a circuit is designed such that its output forms an m-out-of-n code, any fault in the circuit which creates a single bit error or unidirectional multibit error at the output can be detected on-line. On-line error detection, also known as self-checking, can be accomplished by using a checker to monitor the circuit output. The output of the checker is 01 or 10 if there is no fault in the circuit under test or in the checker itself, otherwise the output will be 00 or 11.

  15. Performance Characteristics of an Isothermal Freeze Valve

    Energy Technology Data Exchange (ETDEWEB)

    Hailey, A.E.

    2001-08-22

    This document discusses performance characteristics of an isothermal freeze valve. A freeze valve has been specified for draining the DWPF melter at the end of its lifetime. Two freeze valve designs have been evaluated on the Small Cylindrical Melter-2 (SCM-2). In order to size the DWPF freeze valve, the basic principles governing freeze valve behavior need to be identified and understood.

  16. Condition monitoring through advanced sensor and computational technology : final report (January 2002 to May 2005).

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung-Taek (Korea Atomic Energy Research Institute, Daejon, Korea); Luk, Vincent K.

    2005-05-01

    The overall goal of this joint research project was to develop and demonstrate advanced sensors and computational technology for continuous monitoring of the condition of components, structures, and systems in advanced and next-generation nuclear power plants (NPPs). This project included investigating and adapting several advanced sensor technologies from Korean and US national laboratory research communities, some of which were developed and applied in non-nuclear industries. The project team investigated and developed sophisticated signal processing, noise reduction, and pattern recognition techniques and algorithms. The researchers installed sensors and conducted condition monitoring tests on two test loops, a check valve (an active component) and a piping elbow (a passive component), to demonstrate the feasibility of using advanced sensors and computational technology to achieve the project goal. Acoustic emission (AE) devices, optical fiber sensors, accelerometers, and ultrasonic transducers (UTs) were used to detect mechanical vibratory response of check valve and piping elbow in normal and degraded configurations. Chemical sensors were also installed to monitor the water chemistry in the piping elbow test loop. Analysis results of processed sensor data indicate that it is feasible to differentiate between the normal and degraded (with selected degradation mechanisms) configurations of these two components from the acquired sensor signals, but it is questionable that these methods can reliably identify the level and type of degradation. Additional research and development efforts are needed to refine the differentiation techniques and to reduce the level of uncertainties.

  17. Semi-active compressor valve

    Science.gov (United States)

    Brun, Klaus; Gernentz, Ryan S.

    2010-07-27

    A method and system for fine-tuning the motion of suction or discharge valves associated with cylinders of a reciprocating gas compressor, such as the large compressors used for natural gas transmission. The valve's primary driving force is conventional, but the valve also uses an electromagnetic coil to sense position of the plate (or other plugging element) and to provide an opposing force prior to impact.

  18. Telocytes in human heart valves

    OpenAIRE

    Yang, Yang; Sun, Wei; Wu, Sean M; Xiao, Junjie; Kong, Xiangqing

    2014-01-01

    Valve interstitial cells (VICs) are responsible for maintaining the structural integrity and dynamic behaviour of the valve. Telocytes (TCs), a peculiar type of interstitial cells, have been recently identified by Popescu*s group in epicardium, myocardium and endocardium (visit http://www.telocytes.com). The presence of TCs has been identified in atria, ventricles and many other tissues and organ, but not yet in heart valves. We used transmission electron microscopy and immunofluorescence met...

  19. Innovative Stemless Valve Eliminates Emissions

    Science.gov (United States)

    2008-01-01

    Big Horn Valve Inc. (BHVI), of Sheridan, Wyoming, won a series of SBIR and Small Business Technology Transfer (STTR) contracts with Kennedy Space Center and Marshall Space Flight Center to explore and develop a revolutionary valve technology. BHVI developed a low-mass, high-efficiency, leak-proof cryogenic valve using composites and exotic metals, and had no stem-actuator, few moving parts, with an overall cylindrical shape. The valve has been installed at a methane coal gas field, and future applications are expected to include in-flight refueling of military aircraft, high-volume gas delivery systems, petroleum refining, and in the nuclear industry.

  20. Latest design of gate valves

    Energy Technology Data Exchange (ETDEWEB)

    Kurzhofer, U.; Stolte, J.; Weyand, M.

    1996-12-01

    Babcock Sempell, one of the most important valve manufacturers in Europe, has delivered valves for the nuclear power industry since the beginning of the peaceful application of nuclear power in the 1960s. The latest innovation by Babcock Sempell is a gate valve that meets all recent technical requirements of the nuclear power technology. At the moment in the United States, Germany, Sweden, and many other countries, motor-operated gate and globe valves are judged very critically. Besides the absolute control of the so-called {open_quotes}trip failure,{close_quotes} the integrity of all valve parts submitted to operational forces must be maintained. In case of failure of the limit and torque switches, all valve designs have been tested with respect to the quality of guidance of the gate. The guidances (i.e., guides) shall avoid a tilting of the gate during the closing procedure. The gate valve newly designed by Babcock Sempell fulfills all these characteristic criteria. In addition, the valve has cobalt-free seat hardfacing, the suitability of which has been proven by friction tests as well as full-scale blowdown tests at the GAP of Siemens in Karlstein, West Germany. Babcock Sempell was to deliver more than 30 gate valves of this type for 5 Swedish nuclear power stations by autumn 1995. In the presentation, the author will report on the testing performed, qualifications, and sizing criteria which led to the new technical design.

  1. Monitoring

    Czech Academy of Sciences Publication Activity Database

    Ložek, Vojen; Němec, J.

    Praha : Consult, 2003 - (Němec, J.), s. 111-115 ISBN 80-902132-4-3 Grant ostatní: Magistrát hlavního města Prahy(CZ) DAG/67/04/000176/2001 Institutional research plan: CEZ:AV0Z3013912 Keywords : monitoring * environmental quality * Prague Subject RIV: DB - Geology ; Mineralogy

  2. Monitoring

    Science.gov (United States)

    ... its main source of fuel. To keep your blood sugar level on target and avoid problems with your eyes, kidneys, heart and feet, you should eat right ... better. And monitoring doesn’t stop at measuring blood sugar levels. Because ... blood testing) Eye health (eye exams) Foot health (foot exams and ...

  3. Low energy high pressure miniature screw valve

    Science.gov (United States)

    Fischer, Gary J.; Spletzer, Barry L.

    2006-12-12

    A low energy high pressure screw valve having a valve body having an upper portion and a lower portion, said lower portion of said valve body defining an inlet flow passage and an outlet flow passage traversing said valve body to a valve seat, said upper portion of said valve body defining a cavity at said valve seat, a diaphragm restricting flow between said upper portion of said valve body and said lower portion, said diaphragm capable of engaging said valve seat to restrict fluid communication between said inlet passage and said outlet passage, a plunger within said cavity supporting said diaphragm, said plunger being capable of engaging said diaphragm with said valve seat at said inlet and outlet fluid passages, said plunger being in point contact with a drive screw having threads engaged with opposing threads within said upper portion of said valve body such engagement allowing motion of said drive screw within said valve body.

  4. Whitey Gauge and Root Valves (VPS)

    Energy Technology Data Exchange (ETDEWEB)

    MISKA, C.

    2000-09-03

    These valves are 1/2 inch ball valves fabricated of 316 stainless steel: Packing is TFE (standard). They are used as isolation valves for pressure instrumentation in the Vacuum Pumping and Helium System.

  5. Process control monitoring systems, industrial plants, and process control monitoring methods

    Science.gov (United States)

    Skorpik, James R [Kennewick, WA; Gosselin, Stephen R [Richland, WA; Harris, Joe C [Kennewick, WA

    2010-09-07

    A system comprises a valve; a plurality of RFID sensor assemblies coupled to the valve to monitor a plurality of parameters associated with the valve; a control tag configured to wirelessly communicate with the respective tags that are coupled to the valve, the control tag being further configured to communicate with an RF reader; and an RF reader configured to selectively communicate with the control tag, the reader including an RF receiver. Other systems and methods are also provided.

  6. 14 CFR 91.1089 - Qualifications: Check pilots (aircraft) and check pilots (simulator).

    Science.gov (United States)

    2010-01-01

    ... check pilots (simulator). 91.1089 Section 91.1089 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... (aircraft) and check pilots (simulator). (a) For the purposes of this section and § 91.1093: (1) A check... simulator, or in a flight training device for a particular type aircraft. (2) A check pilot (simulator) is...

  7. 14 CFR 121.411 - Qualifications: Check airmen (airplane) and check airmen (simulator).

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Qualifications: Check airmen (airplane) and... § 121.411 Qualifications: Check airmen (airplane) and check airmen (simulator). (a) For the purposes of this section and § 121.413: (1) A check airman (airplane) is a person who is qualified, and...

  8. Safety relief valve instabilities

    International Nuclear Information System (INIS)

    The opening and closing of safety relief valves induce pressure vibrations and respective loads on the piping system. The quantification of the internal pressure load and the pipe segment forces for the proof of the structural integrity of the piping system and the supports is performed using the code DYVRO. It is not clear whether the calculated result of high-frequent opening and closing shows a realistic behavior or is caused by a simplified modeling. The contribution offers strategic recommendations to avoid unrealistic calculations.

  9. High Reliability Cryogenic Piezoelectric Valve Actuator Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cryogenic fluid valves are subject to harsh exposure and actuators to drive these valves require robust performance and high reliability. DSM's piezoelectric...

  10. A review of digital radiography technology for valve inspection

    International Nuclear Information System (INIS)

    There are thousands of valves in a nuclear power plant (NPP) used for control, safety and checks in various plant systems, so there is a well-identified need for fast and reliable inspection and diagnostics of valves. Digital radiography can provide considerable improvements to the inspection and testing procedures for valves in comparison to classical film radiography. These improvements can lead to significant financial advantages by providing real-time inspection results, significantly reduced inspection and decision-making time, and reduced operational cost. Digital image processing, including digital image enhancement, digital archiving, and digital communication of the images and the results, is also a considerable advantage over classical film radiography technology. Another advantage of digital radiography technology is the improved safety and the reduced environmental impact due to reduced exposure/test times, use of smaller exclusion zones, elimination of chemical processing, and absence of disposable materials. This paper reviews the existing technology and evaluates the potential of digital radiography for inspection and diagnostics of valves. Station needs and requirements are assessed, and the safety, environmental and economical constraints of digital radiography techniques estimated. The advantages and disadvantages of different digital radiography equipment are compared, and their limitations and characteristics studied. (author)

  11. Valve replacement at Calvert Cliffs

    International Nuclear Information System (INIS)

    This article describes how new valves helped solve plant's chronic salt water system problems resulting from years of design changes required by regulations that resulted in operational efficiency-related problems. The topics of the article include harsh service conditions (salt water related corrosion, biological fouling and tearing of rubber liners of valves), spare parts headaches and the permanent solution

  12. What Causes Heart Valve Disease?

    Science.gov (United States)

    ... other infections with strep bacteria that progress to rheumatic fever can cause heart valve disease. When the body tries to fight the strep ... you feel better before the medicine is gone. Heart valve disease caused by rheumatic fever mainly affects older adults who had strep ...

  13. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... Terry asks if you do robotic valve replacement surgeries. I do not. It's a good question. You know, there's a handful of surgeons, frankly, in the world that I think do enough robotic cardiac surgery, whether it be valve surgery or coronary bypass ...

  14. Variable gas leak rate valve

    Science.gov (United States)

    Eernisse, Errol P.; Peterson, Gary D.

    1976-01-01

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

  15. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... valve in the aortic position will grow over time and proves a nice replacement. However, that's sort of operating on two valves to fix one valvular problem. And for most patients in our practice in their 50s, 60s, et cetera, we tend ...

  16. Anonymity control in electronic check systems

    Institute of Scientific and Technical Information of China (English)

    Ma Chunguang; Yang Yixian; Hu Zhengming

    2005-01-01

    Electronic check systems, as one of electronic payment systems, are more desirable than other electronic cash systems. In the system, only a single check is used to pay any price that is not more than the face value. The main problem in check systems is to design an efficient refund mechanism that makes refund checks undistinguished from initial checks during payment and deposit. The problem of anonymity control also called fairness is also an important issue in check systems. All check systems yet are unconditional anonymity that opens the door to misuse for crime such as laundering and blackmailing. In this paper, the notion of anonymity revocation is introduced to electronic check system for the first time, and a model of fair electronic check system is proposed. An efficient fair online electronic check system with reusable refund is presented. In the system, a passive trustee is employed to revoke the anonymity of un-honest users. Moreover, the system solves the reusability problem of refunds thanks to the RSA-based partially signature. The system is efficient and meets all basic security requirements.

  17. A discussion of system reliability and the relative importance of pumps and valves to overall system availability

    Energy Technology Data Exchange (ETDEWEB)

    Poole, A.B. [Oak Ridge National Lab., TN (United States)

    1996-12-01

    An analysis was undertaken to establish preliminary trends for how component aging can effect failure rates for swing check valves, centrifugal pumps and motor operated valves. These failure rate trends were evaluated over time and linear aging rate models established. The failure rate models were then used with classic reliability theories to estimate reliability as a function of operating time. Reliability theory was also used to establish a simple system reliability model. Using the system model, the relative importance of pumps and valves to the overall system reliability were studied. Conclusions were established relative to overall system availability over time and the relative unavailabilities of the various components studied.

  18. Quality team approach to valve reliability

    International Nuclear Information System (INIS)

    In mid-1985, due to the unacceptable failure of valves, a commitment was made to implement a comprehensive valve improvement program at Duke Power Company (DPC). To accomplish an immediate, significant improvement in the quality of valve maintenance execution, a system to provide additional detailed engineering and technical support to the individual valve maintenance crews was first developed and utilized at the Oconee nuclear station in the fall of 1985. This system was later implemented at the other two DPC nuclear stations. The total number of valves on the seven nuclear units is ∼ 140,000. With such a large number of valves, even a small percentage of problem valves can have a major impact on unit availability. Other long-range improvements, such as replacement of selected problem valves and improved, valve-specific training for dedicated valve crews, will ensure even higher valve and station reliability in the future

  19. Heteroscedasticity checks for regression models

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    For checking on heteroscedasticity in regression models, a unified approach is proposed to constructing test statistics in parametric and nonparametric regression models. For nonparametric regression, the test is not affected sensitively by the choice of smoothing parameters which are involved in estimation of the nonparametric regression function. The limiting null distribution of the test statistic remains the same in a wide range of the smoothing parameters. When the covariate is one-dimensional, the tests are, under some conditions, asymptotically distribution-free. In the high-dimensional cases, the validity of bootstrap approximations is investigated. It is shown that a variant of the wild bootstrap is consistent while the classical bootstrap is not in the general case, but is applicable if some extra assumption on conditional variance of the squared error is imposed. A simulation study is performed to provide evidence of how the tests work and compare with tests that have appeared in the literature. The approach may readily be extended to handle partial linear, and linear autoregressive models.

  20. Control-flow checking via regular expressions

    OpenAIRE

    Benso, Alfredo; Di Natale, Giorgio; Di Carlo, Stefano; Prinetto, Paolo Ernesto; Tagliaferri, Luca

    2001-01-01

    The present paper explains a new approach to program control flow checking. The check has been inserted at source-code level using a signature methodology based on regular expressions. The signature checking is performed without a dedicated watchdog processor but resorting to inter-process communication (IPC) facilities offered by most of the modern operating systems. The proposed approach allows very low memory overhead and trade-off between fault latency and program execution time overhead

  1. An experimental analysis of body checking

    OpenAIRE

    Shafran, Roz; Lee, Michelle; Payne, Elizabeth; Fairburn, Christopher G.

    2007-01-01

    The relationship between repeated body checking and its impact on body size estimation and body dissatisfaction is of interest for two reasons. First, it has importance in theoretical accounts of the maintenance of eating disorders and, second, body checking is targeted in cognitive-behavioural treatment. The aim of this study was to determine the impact of manipulating body checking on body size estimation and body dissatisfaction. Sixty women were randomly assigned either to repeatedly scru...

  2. Self-Rupturing Hermetic Valve

    Science.gov (United States)

    Tucker, Curtis E., Jr.; Sherrit, Stewart

    2011-01-01

    For commercial, military, and aerospace applications, low-cost, small, reliable, and lightweight gas and liquid hermetically sealed valves with post initiation on/off capability are highly desirable for pressurized systems. Applications include remote fire suppression, single-use system-pressurization systems, spacecraft propellant systems, and in situ instruments. Current pyrotechnic- activated rupture disk hermetic valves were designed for physically larger systems and are heavy and integrate poorly with portable equipment, aircraft, and small spacecraft and instrument systems. Additionally, current pyrotechnically activated systems impart high g-force shock loads to surrounding components and structures, which increase the risk of damage and can require additional mitigation. The disclosed mechanism addresses the need for producing a hermetically sealed micro-isolation valve for low and high pressure for commercial, aerospace, and spacecraft applications. High-precision electrical discharge machining (EDM) parts allow for the machining of mated parts with gaps less than a thousandth of an inch. These high-precision parts are used to support against pressure and extrusion, a thin hermetically welded diaphragm. This diaphragm ruptures from a pressure differential when the support is removed and/or when the plunger is forced against the diaphragm. With the addition of conventional seals to the plunger and a two-way actuator, a derivative of this design would allow nonhermetic use as an on/off or metering valve after the initial rupturing of the hermetic sealing disk. In addition, in a single-use hermetically sealed isolation valve, the valve can be activated without the use of potential leak-inducing valve body penetrations. One implementation of this technology is a high-pressure, high-flow-rate rupture valve that is self-rupturing, which is advantageous for high-pressure applications such as gas isolation valves. Once initiated, this technology is self

  3. New diagnostic possibilities for solenoid valves. Neue Diagnosemoeglichkeiten fuer Magnetventile

    Energy Technology Data Exchange (ETDEWEB)

    Kluever, G. (Herion-Werke KG, Fellbach (Germany))

    1993-05-01

    A diagnostic device, which distinguishes itself by its simple control and operation, has been developed for the early detection of damage in solenoid valves. This device provides all the information which is important for early detection of damage in a VDU representation. Deviations from the specified design power balance of the solenoid valves are detected by comparison of repeat measurements with master diagrams, whilst the calibration curves are superimposed on the monitor. Measurement data input and management are supported by a menu-controlled programme. (orig.)

  4. Giant Thoracic Aneurysm Following Valve Replacement for Bicuspid Aortic Valve.

    Science.gov (United States)

    Tran, Cao; Ul Haq, Ehtesham; Nguyen, Ngoc; Omar, Bassam

    2015-01-01

    Bicuspid aortic valve is a common congenital anomaly associated with aortopathy, which can cause aortic root dilatation, necessitating regular screening if the aortic root is > 4.0 cm. Despite the low absolute incidence of aortic complications associated with bicuspid aortic valve in the general population, the consequences of such complications for an individual patient can be devastating. Herein we propose a balanced algorithm that incorporates recommendations from the three major guidelines for follow-up imaging of the aortic root and ascending thoracic aorta in patients with a bicuspid aortic valve, maintaining the current recommendations with regard to surgical thresholds. PMID:26827748

  5. Implementing wavelet packet transform for valve failure detection using vibration and acoustic emission signals

    International Nuclear Information System (INIS)

    The efficiency of reciprocating compressors relies heavily on the health condition of its moving components, most importantly its valves. Previous studies showed good correlation between the dynamic response and the physical condition of the valves. These can be achieved by employing vibration technique which is capable of monitoring the response of the valve, and acoustic emission technique which is capable of detecting the valves' material deformation. However, the relationship/comparison between the two techniques is rarely investigated. In this paper, the two techniques were examined using time-frequency analysis. Wavelet packet transform (WPT) was chosen as the multi-resolution analysis technique over continuous wavelet transform (CWT), and discrete wavelet transform (DWT). This is because WPT could overcome the high computational time and high redundancy problem in CWT and could provide detailed analysis of the high frequency components compared to DWT. The features of both signals can be extracted by evaluating the normalised WPT coefficients for different time window under different valve conditions. By comparing the normalised coefficients over a certain time frame and frequency range, the feature vectors revealing the condition of valves can be constructed. One way analysis of variance was employed on these feature vectors to test the significance of data under different valve conditions. It is believed that AE signals can give a better representation of the valve condition as it can detect both the fluid motion and material deformation of valves as compared to the vibration signals.

  6. Implementing wavelet packet transform for valve failure detection using vibration and acoustic emission signals

    Science.gov (United States)

    Sim, H. Y.; Ramli, R.; Abdullah, M. A. K.

    2012-05-01

    The efficiency of reciprocating compressors relies heavily on the health condition of its moving components, most importantly its valves. Previous studies showed good correlation between the dynamic response and the physical condition of the valves. These can be achieved by employing vibration technique which is capable of monitoring the response of the valve, and acoustic emission technique which is capable of detecting the valves' material deformation. However, the relationship/comparison between the two techniques is rarely investigated. In this paper, the two techniques were examined using time-frequency analysis. Wavelet packet transform (WPT) was chosen as the multi-resolution analysis technique over continuous wavelet transform (CWT), and discrete wavelet transform (DWT). This is because WPT could overcome the high computational time and high redundancy problem in CWT and could provide detailed analysis of the high frequency components compared to DWT. The features of both signals can be extracted by evaluating the normalised WPT coefficients for different time window under different valve conditions. By comparing the normalised coefficients over a certain time frame and frequency range, the feature vectors revealing the condition of valves can be constructed. One way analysis of variance was employed on these feature vectors to test the significance of data under different valve conditions. It is believed that AE signals can give a better representation of the valve condition as it can detect both the fluid motion and material deformation of valves as compared to the vibration signals.

  7. Twenty-Two-Year Experience with Aortic Valve Replacement: Starr-Edwards Ball Valves versus Disc Valves

    OpenAIRE

    Pilegaard, Hans K.; Lund, Ole; Nielsen, Torsten T; Magnussen, Karin; Knudsen, Mary A; Albrechtsen, Ole K.

    1991-01-01

    From 1965 through 1986, 817 patients underwent aortic valve replacement at our institution. Six hundred forty-five patients received Starr-Edwards ball valves, including 286 Silastic ball valves (Models 1200/1260), 165 cloth-covered caged-ball prostheses (Models 2300/2310/2320), and 194 track-valve prostheses (Model 2400). In contrast, 172 patients received disc-valve prostheses, including 126 St. Jude Medical aortic bi-leaflet disc valves, 32 Lillehei-Kaster pivoting disc valves, and 14 Björ...

  8. Heteroscedasticity checks for regression models

    Institute of Scientific and Technical Information of China (English)

    ZHU; Lixing

    2001-01-01

    [1]Carroll, R. J., Ruppert, D., Transformation and Weighting in Regression, New York: Chapman and Hall, 1988.[2]Cook, R. D., Weisberg, S., Diagnostics for heteroscedasticity in regression, Biometrika, 1988, 70: 1—10.[3]Davidian, M., Carroll, R. J., Variance function estimation, J. Amer. Statist. Assoc., 1987, 82: 1079—1091.[4]Bickel, P., Using residuals robustly I: Tests for heteroscedasticity, Ann. Statist., 1978, 6: 266—291.[5]Carroll, R. J., Ruppert, D., On robust tests for heteroscedasticity, Ann. Statist., 1981, 9: 205—209.[6]Eubank, R. L., Thomas, W., Detecting heteroscedasticity in nonparametric regression, J. Roy. Statist. Soc., Ser. B, 1993, 55: 145—155.[7]Diblasi, A., Bowman, A., Testing for constant variance in a linear model, Statist. and Probab. Letters, 1997, 33: 95—103.[8]Dette, H., Munk, A., Testing heteoscedasticity in nonparametric regression, J. R. Statist. Soc. B, 1998, 60: 693—708.[9]Müller, H. G., Zhao, P. L., On a semi-parametric variance function model and a test for heteroscedasticity, Ann. Statist., 1995, 23: 946—967.[10]Stute, W., Manteiga, G., Quindimil, M. P., Bootstrap approximations in model checks for regression, J. Amer. Statist. Asso., 1998, 93: 141—149.[11]Stute, W., Thies, G., Zhu, L. X., Model checks for regression: An innovation approach, Ann. Statist., 1998, 26: 1916—1939.[12]Shorack, G. R., Wellner, J. A., Empirical Processes with Applications to Statistics, New York: Wiley, 1986.[13]Efron, B., Bootstrap methods: Another look at the jackknife, Ann. Statist., 1979, 7: 1—26.[14]Wu, C. F. J., Jackknife, bootstrap and other re-sampling methods in regression analysis, Ann. Statist., 1986, 14: 1261—1295.[15]H rdle, W., Mammen, E., Comparing non-parametric versus parametric regression fits, Ann. Statist., 1993, 21: 1926—1947.[16]Liu, R. Y., Bootstrap procedures under some non-i.i.d. models, Ann. Statist., 1988, 16: 1696—1708.[17

  9. Cavitation guide for control valves

    Energy Technology Data Exchange (ETDEWEB)

    Tullis, J.P. [Tullis Engineering Consultants, Logan, UT (United States)

    1993-04-01

    This guide teaches the basic fundamentals of cavitation to provide the reader with an understanding of what causes cavitation, when it occurs, and the potential problems cavitation can cause to a valve and piping system. The document provides guidelines for understanding how to reduce the cavitation and/or select control valves for a cavitating system. The guide provides a method for predicting the cavitation intensity of control valves, and how the effect of cavitation on a system will vary with valve type, valve function, valve size, operating pressure, duration of operation and details of the piping installation. The guide defines six cavitation limits identifying cavitation intensities ranging from inception to the maximum intensity possible. The intensity of the cavitation at each limit Is described, including a brief discussion of how each level of cavitation influences the valve and system. Examples are included to demonstrate how to apply the method, including making both size and pressure scale effects corrections. Methods of controlling cavitation are discussed providing information on various techniques which can be used to design a new system or modify an existing one so it can operate at a desired level of cavitation.

  10. Valve for controlling solids flow

    International Nuclear Information System (INIS)

    A fluidized solids control valve is disclosed that is particularly well adapted for use with a flow of coal or char that includes both large particles and fines. The particles may or may not be fluidized at various times during the operation. The valve includes a tubular body that terminates in a valve seat covered by a normally closed closure plate. The valve body at the seat and the closure plate is provided with aligned longitudinal slots that receive a pivotally supported key plate. The key plate is positionable by an operator in inserted, intermediate and retracted positions respecting the longitudinal slot in the valve body. The key plate normally closes the slot within the closure plate but is shaped and aligned obliquely to the longitudinal slot within the valve body to provide progressively increasing slot openings between the inserted and retracted positions. Transfer members are provided between the operator, key plate and closure plate to move the closure plate into an open position only when the key plate is retracted from the longitudinal slot within the valve body

  11. Cavitation guide for control valves

    International Nuclear Information System (INIS)

    This guide teaches the basic fundamentals of cavitation to provide the reader with an understanding of what causes cavitation, when it occurs, and the potential problems cavitation can cause to a valve and piping system. The document provides guidelines for understanding how to reduce the cavitation and/or select control valves for a cavitating system. The guide provides a method for predicting the cavitation intensity of control valves, and how the effect of cavitation on a system will vary with valve type, valve function, valve size, operating pressure, duration of operation and details of the piping installation. The guide defines six cavitation limits identifying cavitation intensities ranging from inception to the maximum intensity possible. The intensity of the cavitation at each limit Is described, including a brief discussion of how each level of cavitation influences the valve and system. Examples are included to demonstrate how to apply the method, including making both size and pressure scale effects corrections. Methods of controlling cavitation are discussed providing information on various techniques which can be used to design a new system or modify an existing one so it can operate at a desired level of cavitation

  12. Pump and valve research at the Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Over the last several years, the Oak Ridge National Laboratory (ORNL) has carried out several aging assessments on pumps and valves under the NRC's Nuclear Plant Aging Research (NPAR) Program. In addition, ORNL has established an Advanced Diagnostic Engineering Research and Development Center (ADEC) in order to play a key role in the field of diagnostic engineering. Initial ADEC research projects have addressed problems that were identified, at least in part, by the NPAR and other NRC-sponsored programs. Results from these research activities have included the identification and evaluation of existing monitoring methods for pumps and valves, and the development of several new diagnostic techniques. These developments include nonintrusive magnetic monitoring methods for valves and motor current signature analysis (MCSA) techniques for remote testing of electrically-powered equipment, including MOVs and motor-driven pumps. These developments have been successfully demonstrated in the laboratory, in local field installations, and in operating nuclear power plants. They provide useful diagnostic capabilities when used alone and when used in conjunction with other available monitoring equipment. This paper summarizes the pump and valve related research that has been done at ORNL and describes in more detail several diagnostic techniques developed at ORNL that are now commercially available

  13. An analysis of prostate patient computer plan checks

    International Nuclear Information System (INIS)

    Full text: The physics group at the Cancer Therapy Centre, Liverpool Hospital performs independent quality assurance checks on all radiation treatment fields. These checks involve calculating doses from the prescribed monitor units using data independent of the planning computer. In the physics check the dose at the isocentre or other prescription point is calculated and usually no consideration is given to patient inhomogeneities and curvature. This dose is compared with the dose at the same position as derived from the Varian CADPLAN treatment planning system (CTPS). For the treatment of prostate cancer, the most common technique involves four 6MV x-ray fields: AP, PA and two laterals with the dose prescribed to the isocentre as recommended by I.C.R.U. Report 50 ('Prescribing, Recording and Reporting Photon Beam Therapy', International Commission on Radiation Units and Measurements, Bethesda, Maryland, U.S.A., 1993). This work attempts to determine the cause and magnitude of dose variations between CTPS and -physics check derived doses in prostate patients. A set of 50 prostate patients, treated with the above technique, was selected for the study. The physics checks were evaluated and the average patient separations and dose variations were determined. These dose variations were between zero and 5% (median 4%). A median isocentre dose difference of 6.2% between using and not using a bone inhomogeneity correction method has been observed in 6MV x-ray arc treatments of the prostate (Nemeth et al, Med. Dosim., 18:171-177, 1993). The physics check method was benchmarked in a homogeneous solid water phantom using a PTW Farmer type ionisation chamber with the four field prostate technique and compared with the CTPS derived doses. This showed good agreement. An anthropomorphic phantom was treated with the above prostate technique, using a field size of 9x9 cm2 for all four fields. The CTPS and physics check derived doses at the isocentre were calculated and compared

  14. Successful thrombolysis for prosthetic pulmonary valve obstruction.

    OpenAIRE

    Lopez, J. A.; Strickman, N E; Jin, B S; X. G. Li; Phan, B; Zeluff, B J; Wilansky, S

    1995-01-01

    Thrombosis is a serious complication of prosthetic heart valve operations. In recent years, systemic thrombolysis has emerged as a suitable alternative to surgery. Experience with thrombosis of pulmonary prosthetic valves is very limited. We report a case of successful administration of intravenous streptokinase for thrombosis of a St. Jude Medical prosthetic valve 3 weeks after pulmonary valve replacement.

  15. Thermostatic Radiator Valve Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Dentz, J. [Advanced Residential Integrated Energy Solutions Collaborative (ARIES), New York, NY (United States); Ansanelli, E. [Advanced Residential Integrated Energy Solutions Collaborative (ARIES), New York, NY (United States)

    2015-01-01

    A large stock of multifamily buildings in the Northeast and Midwest are heated by steam distribution systems. Losses from these systems are typically high and a significant number of apartments are overheated much of the time. Thermostatically controlled radiator valves (TRVs) are one potential strategy to combat this problem, but have not been widely accepted by the residential retrofit market. In this project, the ARIES team sought to better understand the current usage of TRVs by key market players in steam and hot water heating and to conduct limited experiments on the effectiveness of new and old TRVs as a means of controlling space temperatures and reducing heating fuel consumption. The project included a survey of industry professionals, a field experiment comparing old and new TRVs, and cost-benefit modeling analysis using BEopt™ (Building Energy Optimization software).

  16. Ferroelectric Fluid Flow Control Valve

    Science.gov (United States)

    Jalink, Antony, Jr. (Inventor); Hellbaum, Richard F. (Inventor); Rohrbach, Wayne W. (Inventor)

    1999-01-01

    An active valve is controlled and driven by external electrical actuation of a ferroelectric actuator to provide for improved passage of the fluid during certain time periods and to provide positive closure of the valve during other time periods. The valve provides improved passage in the direction of flow and positive closure in the direction against the flow. The actuator is a dome shaped internally prestressed ferroelectric actuator having a curvature, said dome shaped actuator having a rim and an apex. and a dome height measured from a plane through said rim said apex that varies with an electric voltage applied between an inside and an outside surface of said dome shaped actuator.

  17. Valve leakage inspection testing and maintenance process

    International Nuclear Information System (INIS)

    In valve maintenance, packing rings that prevent leakage along the valve stem must periodically be replaced, either during routine maintenance or to correct a leak or valve malfunction. Tools and procedures currently in use for valve packing removal and inspection are generally of limited value due to various access and application problems. A process has been developed by AECL Research that addresses these problems. The process, using incompressible fluid pressure, quickly and efficiently confirms the integrity of the valve backseat, extracts hard-to-remove valve packing sets, and verifies the leak tightness of the repacked valve

  18. Transcatheter, valve-in-valve transapical aortic and mitral valve implantation, in a high risk patient with aortic and mitral prosthetic valve stenoses

    Directory of Open Access Journals (Sweden)

    Harish Ramakrishna

    2015-01-01

    Full Text Available Transcatheter valve implantation continues to grow worldwide and has been used principally for the nonsurgical management of native aortic valvular disease-as a potentially less invasive method of valve replacement in high-risk and inoperable patients with severe aortic valve stenosis. Given the burden of valvular heart disease in the general population and the increasing numbers of patients who have had previous valve operations, we are now seeing a growing number of high-risk patients presenting with prosthetic valve stenosis, who are not potential surgical candidates. For this high-risk subset transcatheter valve delivery may be the only option. Here, we present an inoperable patient with severe, prosthetic valve aortic and mitral stenosis who was successfully treated with a trans catheter based approach, with a valve-in-valve implantation procedure of both aortic and mitral valves.

  19. In-operation inspection technology development-4 ''development of degradation prediction technology for motor-operated valves''

    Energy Technology Data Exchange (ETDEWEB)

    Kikuo, Takeshima; Yuichi, Higashikawa [Hitachi Engineering and Production Div., Nuclear Systems Div., Hitachi, Ltd., Ibaraki (Japan); Masahiro, Koike [Power and Industrial Systems R and D Lab., Hitachi, Ltd., (Japan); Kenji, Matsumoto [Tokyo Research and Development Center, Japan Power Engineering and Inspection Corp. (Japan); Eiji, O' shima [Tokyo Institute of Technology (Japan)

    2001-07-01

    A method for degradation predicting technology has been proposed for motor operated valves in nuclear power plants which is based on the concept of condition monitoring for maintenance. This method (degradation prediction technology) eliminates the unnecessary overhaul of valves and realizes high reliability and economy. The degradation mechanism was clarified by long time heating experiments of gasket and gland packing and the wear test for them and stem nut to research valve parts degradation by stress (pressure, temperature, etc) during plant operation. Effective electric power measurements for motor operated valves were confirmed to be useful discovering valve part failures. The motor operated valve degradation prediction system was developed on the basis of the experiment results and mechanism. The system is able to predict the degradation of valve parts (gasket/gland packing, stem, stem nut, etc) utilizing plant data (pressure, temperature, etc) and effective power of the motor. The life of valve parts can be estimated from the experimental results. (authors)

  20. Check-In Check-Out + Social Skills: Enhancing the Effects of Check-In Check-Out for Students With Social Skill Deficits

    Science.gov (United States)

    Ross, Scott W.; Sabey, Christian V.

    2015-01-01

    Check-In Check-Out is a Tier 2 intervention designed to reduce problem behavior and increase prosocial behavior. Although the intervention has demonstrated effects in several studies, few research efforts have considered how the intervention can be modified to support students with social skill deficits. Through a multiple baseline design across…

  1. 7 CFR 58.243 - Checking quality.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Checking quality. 58.243 Section 58.243 Agriculture... Procedures § 58.243 Checking quality. All milk, milk products and dry milk products shall be subject to inspection and analysis by the dairy plant for quality and condition throughout each processing...

  2. Tractor Mechanic Check Sheets for Modules.

    Science.gov (United States)

    Clemson Univ., SC. Vocational Education Media Center.

    Forms for student self-checks and the instructor's final checklist (student evaluation) are provided for use with thirty-three learning modules on maintaining and servicing fuel and electrical systems in tractor mechanics. The student self-check asks the students questions about their understanding of the modules' content. The instructor's…

  3. The model checking fingerprints of CTL operators

    OpenAIRE

    Krebs, Andreas; Meier, Arne; Mundhenk, Martin

    2015-01-01

    The aim of this study is to understand the inherent expressive power of CTL operators. We investigate the complexity of model checking for all CTL fragments with one CTL operator and arbitrary Boolean operators. This gives us a fingerprint of each CTL operator. The comparison between the fingerprints yields a hierarchy of the operators that mirrors their strength with respect to model checking.

  4. Automatization and familiarity in repeated checking

    NARCIS (Netherlands)

    Dek, E.C.P.; van den Hout, M.A.; Giele, C.L.; Engelhard, I.M.

    2015-01-01

    Repetitive, compulsive-like checking of an object leads to reductions in memory confidence, vividness, and detail. Experimental research suggests that this is caused by increased familiarity with perceptual characteristics of the stimulus and automatization of the checking procedure (Dek, van den Ho

  5. QuickChecking Static Analysis Properties

    DEFF Research Database (Denmark)

    Midtgaard, Jan; Møller, Anders

    2015-01-01

    A static analysis can check programs for potential errors. A natural question that arises is therefore: who checks the checker? Researchers have given this question varying attention, ranging from basic testing techniques, informal monotonicity arguments, thorough pen-and-paper soundness proofs, ...

  6. Mechanical heart valve cavitation in patients with bileaflet valves.

    Science.gov (United States)

    Johansen, Peter; Andersen, Tina S; Hasenkam, J Michael; Nygaard, Hans; Paulsen, Peter K

    2014-01-01

    Today, the quality of mechanical heart valves is quite high, and implantation has become a routine clinical procedure with a low operative mortality (valves are thought of having higher cavitation potential than bileaflet valves due to higher closing velocities. However, the thromboembolic potential seems to be the same. Further studies are therefore needed to investigate the cavitation potential of bileaflet valves in vivo. The post processing of HFPF have shown difficulties when applied on bileaflet vavles due to asynchronous closure of the two leaflets. The aim of this study was therefore to isolate the pressure signature from each leaflet closure and perform cavitation analyses on each component. Six patients were included in the study (St. Jude Medical (n=3) and CarboMedics (n=3); all aortic bileaflet mechanical heart valves). HFPFs were recorded intraoperatively through a hydrophone at the aortic root. The pressure signature relating to the first and second leaflet closure was isolated and cavitation parameters were calculated (RMS after 50 kHz highpass filtering and signal energy). Data were averaged over 30 heart cycles. For all patients both the RMS value and signal energy of the second leaflet closure were higher than for the first leaflet closure. This indicates that the second leaflet closure is most prone to cause cavitation. Therefore, quantifying cavitation based on the HFPF related to the second leaflet closure may suggest that the cavitation potential for bileaflet valves in vivo may be higher than previous studies have suggested. PMID:25571278

  7. A photoelectrically actuated, motor-operated valve stroke timer

    International Nuclear Information System (INIS)

    Questions have been raised about the value of Motor-Operated Valve (MOV) stroke timing in nuclear power plants, and, reevaluations of requirements in this area have recently been done by the ASME O ampersand M Committee Working Group on Pumps and Valves. Quoting an August 12, 1988, submittal to the Committee by W.L. Greenstreet from Oak Ridge National Laboratories, stroke time data, if made more Precise and carefully analyzed, can yield valuable operational readiness and diagnostic information. This paper presents a battery-powered, photoelectrically actuated timer developed by the Chicago Nuclear Corporation for precision MOV stroke timing. The timer receives input from valve position indicating lights on the main control panel and can easily be used with existing plant procedures. The paper also describes analysis and evaluation techniques to be applied to the data in monitoring valve operability. The techniques described apply the data to specific valve operator characteristics, thereby increasing the quality of MOV operability assessments. Both ac and dc motor operators are considered

  8. Defining indicators to motorize block valves aiming to reduce potential leakage applied to OSBRA pipeline

    Energy Technology Data Exchange (ETDEWEB)

    Pires, L.F.G. [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil); Sousa, A.G.; Castro, N.C.; Spagnolo, R. [Petrobras Transporte S.A. (TRANSPETRO), Rio de Janeiro, RJ (Brazil)

    2009-07-01

    The discussion about motorizing block valves is a constant point being brought up when it is intended to control or reduce the amount of liquid leaking in the event of a pipe rupture. During the pipeline's project stage the installation of blocking valves along the pipeline must be taken into consideration to meet the operation and maintenance requirements as well as to reduce the potential amounts of volume being leaked. In existing pipelines, the main concern is the definition of which valves are candidates to be motorized. In both situations criteria should be established to define this choice. A math algorithm was developed to define the potential leakage due to gravity along the pipeline profile where the influence of a valve over another is verified, as well as the contribution of the check valves existing in the pipeline. The present work defines a parameter based on the extension protected by the valve and the reduction of the potential leakage. This parameter is then fed to a worksheet where the efficiency indicators are calculated to each valve eligible to be motorized. It also takes into consideration factors relative to the valve location, such as the environmental sensitivity, risk assessment, social diagnosis and device's proximity to contingency resources. Finally, after considering all the above aspects, it's possible to come up with a final classification, recommending specific valves to be prioritized on an eventual process of motorization adequacies. This methodology was applied, experimentally on a pipe segment of TRANSPETRO's Sao Paulo-Brasilia pipeline - OSBRA , where it proved to be an important technological and management tool. (author)

  9. Arithmetic Operand Ordering for Equivalence Checking

    Institute of Scientific and Technical Information of China (English)

    WENG Yanling; GE Haitong; YAN Xiaolang; Ren Kun

    2007-01-01

    An information extraction-based technique is proposed for RTL-to-gate equivalence checking. Distances are calculated on directed acyclic graph (AIG). Multiplier and multiplicand are distinguished on multiplications with different coding methods, with which the operand ordering/grouping information could be extracted from a given implementation gate netlist, helping the RTL synthesis engine generate a gate netlist with great similarity. This technique has been implemented in an internal equivalence checking tool, ZD_VIS. Compared with the simple equivalence checking, the speed is accelerated by at least 40% in its application to a class of arithmetic designs, addition and multiplication trees. The method can be easily incorporated into existing RTL-to-gate equivalence checking frameworks, increasing the robustness of equivalence checking for arithmetic circuits.

  10. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... benefits are much more than that of cosmesis. Let me just preface that by saying that my ... any patient who has a prosthetic valve should let all their treating physicians, dentists, et cetera, know ...

  11. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... see we've used the cautery to achieve access to the sternum. On the left hand side ... wound, which allows us to get more ready access to the aorta and the aortic valve. The ...

  12. Simpler valve for reciprocating engines

    Science.gov (United States)

    Akkerman, J. W.

    1978-01-01

    Simpler design eliminating camshafts, cams, and mechanical springs should improve reliability of hydrazine powered reciprocating engines. Valve is expected to improve efficiency, and reduce weight of engines in range up to 50 horsepower.

  13. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... a rare problem where the patient's own immune system will attack cardiac valve structures, causing them to ... it be heart, lung et cetera, the immune system recognizes those living issues as not being from ...

  14. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... or the devices used in this continuing medical educational activity. Thanks, John, we want to remind the ... a rare problem where the patient's own immune system will attack cardiac valve structures, causing them to ...

  15. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... for patients who would not tolerate well a traditional open operation or a less invasive operation, as ... physical reserve. So Barbara Bush recently had a traditional aortic valve replacement surgery. What makes a patient ...

  16. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... valve, it's just 1 sort of a normal aging process that we see in a certain segment ... this country is primarily a disease of the aging population. And, of course, we are a country ...

  17. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... in both of those prosthetics. And so in theory, the risk of prosthetic valvular endocarditis is the ... Doug has also asked if the electrical pacing system is located anywhere near that valve and how ...

  18. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... at the body's surface area. We, in the operating room, have a set of sizers which allow ... proves a nice replacement. However, that's sort of operating on two valves to fix one valvular problem. ...

  19. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... patients in the sixth and seventh decades of life. Again, some areas of the valve appear normal ... have been proven to slow that disease path life. Again, it's a progressive disease from sclerosis, or ...

  20. Minimally Invasive Aortic Valve Replacement

    Science.gov (United States)

    ... made out of either tissues from cows or pigs, what we call porcine for pigs and bovine for cows. Essentially, the tissue from ... we generally recommend explantation and reimplantation of a sterile valve. Again, I want to underscore that any ...

  1. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... other cardiovascular diseases including heart attack and increased risk of cardiovascular death. John, is there anything you ... with time. This highlights the mortality or the risk of death associated with aortic valve replacement and ...

  2. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... who have symptomatic aortic stenosis of a severe nature. It's even been liberalized in some patient populations ... the heart. The aortic valve, because of its nature being in back of the heart, is not ...

  3. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... Dr. Jim Winkley, who's a cardiac anesthesiologist that works here with us. Before we begin, viewers need ... the valve itself has narrowed, that puts more work on the heart when a patient's at rest. ...

  4. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... heart valve which is made out of pyrolitic carbon, basically metal and plastic. Again, blood flows through ... heart surgery here, we actually insufflate, or instill carbon dioxide gas into the field, which we think ...

  5. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... valve is made of three pieces of thin tissue that opens freely when the heart contracts. On ... a lot of calcium and thickening of that tissue and does not open easily or appropriately. This ...

  6. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... North Carolina. My name is John Streitman and I'm a cardiothoracic surgeon here at the Heart ... the corrective surgery of aortic valve replacement. If I have aortic stenosis, are there any activities that ...

  7. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... Winkley nor myself have any financial or professional relationships with the manufacturers or the devices used in ... John, just to interrupt for moment, Charles, Charles V., asks can the mitral valve also be replaced ...

  8. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... patient's heart should have to undergo. Once again, serial evaluations, as with any chronic disease process, are ... to prevent such a problem. Is there a higher risk in someone with a biological valve for ...

  9. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... Jim. Those are coming. There are several valve companies in this country and in Europe that have ... that we've had customized by an instrument company for this approach that really works nicely for ...

  10. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... valves are an excellent option. They have great properties, from a hemodynamic perspective. Their main limitation is ... Dacron sewing ring. Dacron is a woven polyester material that's used for -- it's basically a medical grade ...

  11. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... back in World War II to look for things in the water. Basically, you use sound waves ... valve replacements a year. So one of the things I 10 would counsel anybody is before they ...

  12. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... starts out as a disease we call aortic sclerosis, which is the beginning of the process of ... path life. Again, it's a progressive disease from sclerosis, or the beginning of thickening of the valve, ...

  13. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... and then requires a cadaveric, or a deceased person's, pulmonic valve to be placed in place of ... any procedure, never be afraid to ask that person who's doing the procedure, "Have you done it ...

  14. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... surgery in our community. Aortic stenosis is a process by which the aortic valve, which is the ... and does not open easily or appropriately. This process starts out as a disease we call aortic ...

  15. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... thank you, Jim. This is obviously just a model of the heart just to give some perspective ... the aorta at this point. 9 Earlier this month Robin Williams had his aortic valve replaced and ...

  16. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... a patient less post-operative pain, blood loss, lung dysfunction. Certainly we can get these patients up ... thorocotomy is an incision we generally use for lung operations and for some valve operations in which ...

  17. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... conditions or other significant medical problems, the American College of Cardiology recommends aortic valve replacement for basically ... more likely we see aortic stenosis. Again, patient education is part of the evaluation and management of ...

  18. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... when it progresses to stenosis, by either an increase in velocity of blood through the valve or ... in a normal patient, exercise and increased activity increases your heart rate and blood pressure, which then ...

  19. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... algorithms we employ. After we do a detailed history and physical examination, we generally recommend in most ... thinner, or cumadin, anticoagulation to be taken for life. So the tradeoff again is tissue valves not ...

  20. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... that neither Dr. Winkley nor myself have any financial or professional relationships with the manufacturers or the ... a rare problem where the patient's own immune system will attack cardiac valve structures, causing them to ...

  1. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... to prevent such a problem. Is there a higher risk in someone with a biological valve for ... there but in my experience they're no higher than in someone who's had a full sternotomy. ...

  2. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... able to look at the aortic valve very well. In fact, transesophageal echocardiography is the best modality ... use to help evaluate both cardiac function as well as anatomy in patients who need heart surgery. ...

  3. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... see aortic stenosis in patients younger, in their 40s and 50s, if they have congenitally bicuspid, or ... a year and, you know, probably 30 to 40 minimally invasive aortic valve replacements a year. So ...

  4. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... as represented by the red and the blue color. Typically, blood flowing through a valve should be ... and smooth. We shouldn't see very much color such as we're seeing here. To the ...

  5. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... Hospital in Pinehurst, North Carolina. During the program, it's easy for you to learn about the procedure. ... the aortic valve, and proceeds to aortic stenosis. It's really not felt to be due to wear ...

  6. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... surgery. I think as physicians we owe a responsibility to our patients to try to make procedures ... patients back annually, which we feel is our responsibility any time we do valve replacement or repair ...

  7. 14 CFR 135.337 - Qualifications: Check airmen (aircraft) and check airmen (simulator).

    Science.gov (United States)

    2010-01-01

    ... check airmen (simulator). 135.337 Section 135.337 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... (simulator). (a) For the purposes of this section and § 135.339: (1) A check airman (aircraft) is a person who is qualified to conduct flight checks in an aircraft, in a flight simulator, or in a...

  8. Brucella Endocarditis in Prosthetic Valves

    OpenAIRE

    Mehanic, Snjezana; Mulabdic, Velida; Baljic, Rusmir; Hadzovic-Cengic, Meliha; Pinjo, Fikret; Hadziosmanovic, Vesna; Topalovic, Jasna

    2012-01-01

    SUMMARY CONFLICT OF INTEREST: none declared. Introduction Brucella endocarditis (BE) is a rare but severe and potentially lethal manifestation of brucellosis. Pre-existing valves lesions and prosthetic valves (PV) are favorable for BE. Case report We represent the case of a 46-year-old man who was treated at the Clinic for Infectious Diseases, Clinical Center of Sarajevo University, as blood culture positive (Brucella melitensis) mitral and aortic PV endocarditis. He was treated with combined...

  9. Tissue-engineered heart valves

    Czech Academy of Sciences Publication Activity Database

    Filová, Elena; Straka, František; Miřejovský, T.; Mašín, J.; Bačáková, Lucie

    2009-01-01

    Roč. 58, Suppl.2 (2009), S141-S158. ISSN 0862-8408 R&D Projects: GA MŠk(CZ) 1M0510; GA AV ČR(CZ) 1QS500110564 Institutional research plan: CEZ:AV0Z50110509 Keywords : bioarteficial heart valve * valve interstitial cells * pulse flow bioreactor Subject RIV: EI - Biotechnology ; Bionics Impact factor: 1.430, year: 2009

  10. The effect of valve strategy on in-cylinder flow and combustion

    Energy Technology Data Exchange (ETDEWEB)

    Soederberg, F.

    1997-01-01

    This paper examines the effects of different valve strategies and their effect on in-cylinder flow and combustion. A conventional four valve per cylinder otto engine was modified to enable optical access. The flow measurements were made with a two-component laser Doppler velocimetry system. The combustion was monitored by running pressure data from a pressure transducer through a one-zone heat release model. The results show that when the valves operate normally a barrel flow is present and when one valve is closed a swirling flow occurs. No increase in turbulence was found with later phasing, except in the case of very late inlet valve opening and port deactivation. This resulted in a jet with high turbulence, making the combustion fast and stable, even with a very lean mixture ({lambda}=1.8). 6 refs, 44 figs, 4 tabs

  11. Small sodium valve design and operating experience

    International Nuclear Information System (INIS)

    Conventionally, valves for sodium pipes smaller than 125 mm in diameter are called ''small sodium valves''. However, this limit should rather be considered as the lower limit o ''large sodium valves''. In fact, both the largest sizes of small valves and the smallest of large valves can be found in the range of 125-300 mm in diameter. Thus what is said about small valves also applies, for a few valve types, above the 125 mm limit. Sodium valves are described here in a general manner, with no manufacturing details except when necessary for understanding valve behavior. Operating experience is pointed out wherever possible. Finally, some information is given about ongoing or proposed development plans. (U.S.)

  12. Valve-less microdispenser

    Science.gov (United States)

    Tan, Ming Kwang; Xin, Wang; Lee, Weng Kent

    2015-11-01

    We demonstrate the concept of valve-less microdispenser to control of the liquid flow through the nozzle, by incorporating Leidenfrost effect into the nozzle design. When the nozzle is heated above the Leidenfrost point, a thin vapor layer is formed between the heated substrate and the liquid above it. The vapor pressure due to the presence of the vapor layer, together with the effect of surface tension of the liquid, exerted on the liquid-vapor interface, preventing the flow of the liquid through the nozzle. The experimental results shown that nozzles of diameter 400 micrometer and below, the nozzle temperature of 150 degree Celsius is sufficient to prevent the continuous flowing of the liquid, whereas for nozzles of diameter between 400 to 500 micrometer, the nozzle temperature needs to increase to 160 degree Celsius in order to prevent the continuous flowing of the liquid. When nozzle temperature below 160 degree Celsius, intermittent ejection of microdroplets, whose size is a function of nozzle temperature, is observed.

  13. MODELING, VALIDATION AND OPTIMAL DESIGN OF THE CLAMPING FORCE CONTROL VALVE USED IN CONTINUOUSLY VARIABLE TRANSMISSION

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yunshan; LIU Jin'gang; CAI Yuanchun; ZOU Naiwei

    2008-01-01

    Associated dynamic performance of the clamping force control valve used in continuously variable transmission (CVT) is optimized. Firstly, the structure and working principle of the valve are analyzed, and then a dynamic model is set up by means of mechanism analysis. For the purpose of checking the validity of the modeling method, a prototype workpiece of the valve is manufactured for comparison test, and its simulation result follows the experimental result quite well. An associated performance index is founded considering the response time, overshoot and saving energy, and five structural parameters are selected to adjust for deriving the optimal associated performance index. The optimization problem is solved by the genetic algorithm (GA) with necessary constraints. Finally, the properties of the optimized valve are compared with those of the prototype workpiece, and the results prove that the dynamic performance indexes of the optimized valve are much better than those of the prototype workpiece.Key words: Dynamic modeling Optimal design Genetic algorithm Clamping force control valve Continuously variable transmission (CVT)

  14. Incremental Integrity Checking: Limitations and Possibilities

    DEFF Research Database (Denmark)

    Christiansen, Henning; Martinenghi, Davide

    2005-01-01

    Integrity checking is an essential means for the preservation of the intended semantics of a deductive database. Incrementality is the only feasible approach to checking and can be obtained with respect to given update patterns by exploiting query optimization techniques. By reducing the problem to...... query containment, we show that no procedure exists that always returns the best incremental test (aka simplification of integrity constraints), and this according to any reasonable criterion measuring the checking effort. In spite of this theoretical limitation, we develop an effective procedure...

  15. Why your practice must do background checks.

    Science.gov (United States)

    Zupko, Karen

    2007-01-01

    Hiring qualified staff is critical for a medical practice. As many physicians have discovered, taking applicants' resumes on faith can be a mistake. Background company searches show that one in three applicants provide false, inaccurate, misleading, or incomplete information. Fake degrees, false licenses and certifications, and criminal histories are a few of the problems that a proper background check can reveal. This article describes further why background checks are essential, how to incorporate a background check into your hiring process, and some of the legalities involved in the process. PMID:17494489

  16. ELECTRO-RESISTANCE METHOD OF CHECK A PROCESS GRINDING THE ROLLING BEARINGS

    Directory of Open Access Journals (Sweden)

    K. V. Podmasteryev

    2015-08-01

    Full Text Available Base a possibility of monitoring processes of grinding the rolling bearings with use electroresistance method of check. Is write of essence this method, are analyses his peculiarities, which are provide objective information on the condition a object by his grinding. Are consider the results of experimental researches the effective different diagnostically parameters, which are confirm a possibility of realization objective check of grinding the rolling bearings with use electro-resistance method.

  17. Automatic check of the RFX machine signals

    International Nuclear Information System (INIS)

    The paper deals with an automatic computer procedure developed to detect errors or faults in the signal waveforms measured during the operation of the RFX machine. These data are generated by the diagnostic equipment and other sensors installed in the machine and in its power supplies. The signal check is paramount, since even a single faulty waveform may lead to wrong results in the post-processing phase. Due to their large number, the manual inspection of each signal after the pulse is impossible. The check has to be performed as quickly as possible, in order to identify and discard the defective waveforms before their on-line elaboration. To this purpose, the on-line signal check program is integrated in the control data acquisition system of RFX. Presently, the procedure is being used to check the quality of the saved machine pulse data

  18. Computational fact checking from knowledge networks

    CERN Document Server

    Ciampaglia, Giovanni Luca; Rocha, Luis M; Bollen, Johan; Menczer, Filippo; Flammini, Alessandro

    2015-01-01

    Traditional fact checking by expert journalists cannot keep up with the enormous volume of information that is now generated online. Computational fact checking may significantly enhance our ability to evaluate the veracity of dubious information. Here we show that the complexities of human fact checking can be approximated quite well by finding the shortest path between concept nodes under properly defined semantic proximity metrics on knowledge graphs. Framed as a network problem this approach is feasible with efficient computational techniques. We evaluate this approach by examining tens of thousands of claims related to history, entertainment, geography, and biographical information using a public knowledge graph extracted from Wikipedia. Statements independently known to be true consistently receive higher support via our method than do false ones. These findings represent a significant step toward scalable computational fact-checking methods that may one day mitigate the spread of harmful misinformation...

  19. Computational Fact Checking from Knowledge Networks.

    Directory of Open Access Journals (Sweden)

    Giovanni Luca Ciampaglia

    Full Text Available Traditional fact checking by expert journalists cannot keep up with the enormous volume of information that is now generated online. Computational fact checking may significantly enhance our ability to evaluate the veracity of dubious information. Here we show that the complexities of human fact checking can be approximated quite well by finding the shortest path between concept nodes under properly defined semantic proximity metrics on knowledge graphs. Framed as a network problem this approach is feasible with efficient computational techniques. We evaluate this approach by examining tens of thousands of claims related to history, entertainment, geography, and biographical information using a public knowledge graph extracted from Wikipedia. Statements independently known to be true consistently receive higher support via our method than do false ones. These findings represent a significant step toward scalable computational fact-checking methods that may one day mitigate the spread of harmful misinformation.

  20. For Better Skin Cancer Checks, Partner Up

    Science.gov (United States)

    ... medlineplus.gov/news/fullstory_159632.html For Better Skin Cancer Checks, Partner Up Melanoma survivors benefited when they ... out: Getting a partner trained to spot potential skin cancers can be a lifesaver for melanoma survivors, a ...

  1. Computational Fact Checking from Knowledge Networks

    Science.gov (United States)

    Ciampaglia, Giovanni Luca; Shiralkar, Prashant; Rocha, Luis M.; Bollen, Johan; Menczer, Filippo; Flammini, Alessandro

    2015-01-01

    Traditional fact checking by expert journalists cannot keep up with the enormous volume of information that is now generated online. Computational fact checking may significantly enhance our ability to evaluate the veracity of dubious information. Here we show that the complexities of human fact checking can be approximated quite well by finding the shortest path between concept nodes under properly defined semantic proximity metrics on knowledge graphs. Framed as a network problem this approach is feasible with efficient computational techniques. We evaluate this approach by examining tens of thousands of claims related to history, entertainment, geography, and biographical information using a public knowledge graph extracted from Wikipedia. Statements independently known to be true consistently receive higher support via our method than do false ones. These findings represent a significant step toward scalable computational fact-checking methods that may one day mitigate the spread of harmful misinformation. PMID:26083336

  2. Consistency Checking of Web Service Contracts

    DEFF Research Database (Denmark)

    Cambronero, M. Emilia; Okika, Joseph C.; Ravn, Anders Peter

    2008-01-01

    Behavioural properties are analyzed for web service contracts formulated in Business Process Execution Language (BPEL) and Choreography Description Language (CDL). The key result reported is an automated technique to check consistency between protocol aspects of the contracts. The contracts are...

  3. CMM Interim Check Design of Experiments (U)

    Energy Technology Data Exchange (ETDEWEB)

    Montano, Joshua Daniel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-07-29

    Coordinate Measuring Machines (CMM) are widely used in industry, throughout the Nuclear Weapons Complex and at Los Alamos National Laboratory (LANL) to verify part conformance to design definition. Calibration cycles for CMMs at LANL are predominantly one year in length and include a weekly interim check to reduce risk. The CMM interim check makes use of Renishaw’s Machine Checking Gauge which is an off-the-shelf product simulates a large sphere within a CMM’s measurement volume and allows for error estimation. As verification on the interim check process a design of experiments investigation was proposed to test a couple of key factors (location and inspector). The results from the two-factor factorial experiment proved that location influenced results more than the inspector or interaction.

  4. Health Check Tools: MedlinePlus

    Science.gov (United States)

    ... of this page: https://medlineplus.gov/healthchecktools.html Health Check Tools To use the sharing features on ... Schedule (Centers for Disease Control and Prevention) Children's Health Body Mass Index: Calculator for Child and Teen ( ...

  5. Fluid dynamics of heart valves during atrial fibrillation: a lumped parameter-based approach

    CERN Document Server

    Scarsoglio, Stefania; Guala, Andrea; Ridolfi, Luca

    2015-01-01

    Atrial fibrillation (AF) consequences on the heart valve dynamics are usually studied along with a valvular disfunction or disease, since in medical monitoring the two pathologies are often concomitant. Aim of the present work is to study, through a stochastic lumped-parameter approach, the basic fluid dynamics variations of heart valves, when only paroxysmal AF is present with respect to the normal sinus rhythm (NSR) in absence of any valvular pathology. Among the most common parameters interpreting the valvular function, the most useful turns out to be the regurgitant volume. During AF both atrial valves do not seem to worsen their performance, while the ventricular efficiency is remarkably reduced.

  6. Fluid dynamics of heart valves during atrial fibrillation: a lumped parameter-based approach.

    Science.gov (United States)

    Scarsoglio, S; Camporeale, C; Guala, A; Ridolfi, L

    2016-08-01

    Atrial fibrillation (AF) consequences on the heart valve dynamics are usually studied along with a valvular disfunction or disease, since in medical monitoring, the two pathologies are often concomitant. Aim of the present work is to study, through a stochastic lumped-parameter approach, the basic fluid dynamics variations of heart valves, when only paroxysmal AF is present with respect to the normal sinus rhythm in absence of any valvular pathology. Among the most common parameters interpreting the valvular function, the most useful turns out to be the regurgitant volume. During AF, both atrial valves do not seem to worsen their performance, while the ventricular efficiency is remarkably reduced. PMID:26460925

  7. Engineering Abstractions in Model Checking and Testing

    OpenAIRE

    Achenbach, Michael; Ostermann, Klaus

    2009-01-01

    Abstractions are used in model checking to tackle problems like state space explosion or modeling of IO. The application of these abstractions in real software development processes, however, lacks engineering support. This is one reason why model checking is not widely used in practice yet and testing is still state of the art in falsification. We show how user-defined abstractions can be integrated into a Java PathFinder setting with tools like AspectJ or Javassist and discuss implicati...

  8. Check Point认证简介

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Check Point软件技术有限公司是因特网安全领域的全球著名企业,占有全球65%VPN/防火墙市场份额(IDC 2002),财富前100强中有97家公司采用Check Point的安全产品。

  9. Online treatment compliance checking for clinical pathways.

    Science.gov (United States)

    Huang, Zhengxing; Bao, Yurong; Dong, Wei; Lu, Xudong; Duan, Huilong

    2014-10-01

    Compliance checking for clinical pathways (CPs) is getting increasing attention in health-care organizations due to stricter requirements for cost control and treatment excellence. Many compliance measures have been proposed for treatment behavior inspection in CPs. However, most of them look at aggregated data seen from an external perspective, e.g. length of stay, cost, infection rate, etc., which may provide only a posterior impression of the overall conformance with the established CPs such that in-depth and in near real time checking on the compliance of the essential/critical treatment behaviors of CPs is limited. To provide clinicians real time insights into violations of the established CP specification and support online compliance checking, this article presents a semantic rule-based CP compliance checking system. In detail, we construct a CP ontology (CPO) model to provide a formal grounding of CP compliance checking. Using the proposed CPO, domain treatment constraints are modeled into Semantic Web Rule Language (SWRL) rules to specify the underlying treatment behaviors and their quantified temporal structure in a CP. The established SWRL rules are integrated with the CP workflow such that a series of applicable compliance checking and evaluation can be reminded and recommended during the pathway execution. The proposed approach can, therefore, provides a comprehensive compliance checking service as a paralleling activity to the patient treatment journey of a CP rather than an afterthought. The proposed approach is illustrated with a case study on the unstable angina clinical pathway implemented in the Cardiology Department of a Chinese hospital. The results demonstrate that the approach, as a feasible solution to provide near real time conformance checking of CPs, not only enables clinicians to uncover non-compliant treatment behaviors, but also empowers clinicians with the capability to make informed decisions when dealing with treatment compliance

  10. Generic Architecture for Mobile Check System

    OpenAIRE

    KARIMA MAAZOUZ; HABIB.BENLAHMER; NACEUR.ACHTAICH

    2013-01-01

    the explosion of the market of Smartphone has rapidly changed the way of m-commerce transactions, especially the m-payment systems which are knowing a wide acceptance due to their diversity and the new mobile technologies. In this work we have introduced the system m-check as a mobile payment system, we have presented a generic architecture of the system and the different protocols for the implementation of the system m-check

  11. Generic Architecture for Mobile Check System

    Directory of Open Access Journals (Sweden)

    KARIMA MAAZOUZ

    2013-11-01

    Full Text Available the explosion of the market of Smartphone has rapidly changed the way of m-commerce transactions, especially the m-payment systems which are knowing a wide acceptance due to their diversity and the new mobile technologies. In this work we have introduced the system m-check as a mobile payment system, we have presented a generic architecture of the system and the different protocols for the implementation of the system m-check

  12. Cavitation noise from butterfly valves

    International Nuclear Information System (INIS)

    Cavitation in valves can produce levels of intense noise. It is possible to mathematically express a limit for a design level of cavitation noise in terms of the cavitation parameter sigma. Using the cavitation parameter or limit, it is then possible to calculate the flow conditions at which a design level of cavitation noise will occur. However, the intensity of cavitation increases with the upstream pressure and valve size at a constant sigma. Therefore, it is necessary to derive equations to correct or scale the cavitation limit for the effects of different upstream pressures and valve sizes. The following paper discusses and presents experimental data for the caviation noise limit as well as the cavitation limits of incipient, critical, incipient damage, and choking cavitation for butterfly valves. The main emphasis is on the design limit of caviation noise, and a noise level of 85 decibels was selected as the noise limit. Tables of data and scaling exponents are included for applying the design limits for the effects of upstream pressure and valve size. (orig.)

  13. Analysis of Complex Valve and Feed Systems

    Science.gov (United States)

    Ahuja, Vineet; Hosangadi, Ashvin; Shipman, Jeremy; Cavallo, Peter; Dash, Sanford

    2007-01-01

    A numerical framework for analysis of complex valve systems supports testing of propulsive systems by simulating key valve and control system components in the test loop. In particular, it is designed to enhance the analysis capability in terms of identifying system transients and quantifying the valve response to these transients. This system has analysis capability for simulating valve motion in complex systems operating in diverse flow regimes ranging from compressible gases to cryogenic liquids. A key feature is the hybrid, unstructured framework with sub-models for grid movement and phase change including cryogenic cavitations. The multi-element unstructured framework offers improved predictions of valve performance characteristics under steady conditions for structurally complex valves such as pressure regulator valve. Unsteady simulations of valve motion using this computational approach have been carried out for various valves in operation at Stennis Space Center such as the split-body valve and the 10-in. (approx.25.4-cm) LOX (liquid oxygen) valve and the 4-in. (approx.10 cm) Y-pattern valve (liquid nitrogen). Such simulations make use of variable grid topologies, thereby permitting solution accuracy and resolving important flow physics in the seat region of the moving valve. An advantage to this software includes possible reduction in testing costs incurred due to disruptions relating to unexpected flow transients or functioning of valve/flow control systems. Prediction of the flow anomalies leading to system vibrations, flow resonance, and valve stall can help in valve scheduling and significantly reduce the need for activation tests. This framework has been evaluated for its ability to predict performance metrics like flow coefficient for cavitating venturis and valve coefficient curves, and could be a valuable tool in predicting and understanding anomalous behavior of system components at rocket propulsion testing and design sites.

  14. Condition based maintenance of the motor operated valve in nuclear power plant

    International Nuclear Information System (INIS)

    Approximately 20,000 valves are installed in each nuclear power plant and the inspection by TBM had been adapted mainly. With the application of the new inspection system that has been implemented from January 2009, the need for adapting method conforming to CBM has been examined to optimize the conservation activities in the nuclear power plants. The method of condition monitoring for motor-operated valve with the new diagnosis device and the effectiveness are to be addressed in the speech. (author)

  15. Fluid dynamics of heart valves during atrial fibrillation: a lumped parameter-based approach

    OpenAIRE

    Scarsoglio, Stefania; Camporeale, Carlo; Guala, Andrea; Ridolfi, Luca

    2015-01-01

    Atrial fibrillation (AF) consequences on the heart valve dynamics are usually studied along with a valvular disfunction or disease, since in medical monitoring the two pathologies are often concomitant. Aim of the present work is to study, through a stochastic lumped-parameter approach, the basic fluid dynamics variations of heart valves, when only paroxysmal AF is present with respect to the normal sinus rhythm (NSR) in absence of any valvular pathology. Among the most common parameters inte...

  16. Surface and intracardiac ECG for discriminating conduction disorders after CoreValve implantation

    OpenAIRE

    Akin, I.(Middle East Technical University, Physics Department, Ankara, Turkey); Kische, S.; Schneider, H.; Liebold, A; Ortak, J; Bänsch, D.; Rehders, T. C.; Thiele, O; Schneider, R; Kundt, G; Krenz, H.; Chatterjee, T.; Nienaber, C A; Ince, H

    2011-01-01

    Background Transcatheter aortic valve implantation (TAVI) has been developed to minimize operative morbidity and mortality in high-risk symptomatic patients unfit for open surgery. With the proximity of the aortic valve annulus to the conduction system there is, however, an unknown risk of conduction disturbances necessitating monitoring and often cardiac pacing. Materials and methods We enrolled 50 consecutive patients from January 2007 to 2008 in our prospective evaluation of conduction dis...

  17. Butterfly valve of all rubber lining type

    International Nuclear Information System (INIS)

    The valves used for the circulating water pipes for condensers in nuclear and thermal power stations have become large with the increase of power output, and their specifications have become strict. The materials for the valves change from cast iron to steel plate construction. To cope with sea water corrosion, rubber lining has been applied to the internal surfaces of valve boxes, and the build-up welding of stainless steel has been made on the edges of valves. However, recently it is desired to develop butterfly valves, of which the whole valve disks are lined with hard rubber. For the purpose of confirming the performance of large bore valves, a 2600 mm bore butterfly valve of all rubber lining type was used, and the opening and closing test of 1100 times was carried out by applying thermal cycle and pressure difference and using artifical sea water. Also the bending test of hard rubber lining was performed with test pieces. Thus, it was confirmed that the butterfly valves of all rubber lining type have the performance exceeding that of the valves with build-up welding. The course of development of the valves of all rubber lining type, the construction and the items of confirmation by tests of these valves, and the tests of the valve and the hard rubber lining described above are reported. (Kako, I.)

  18. Prosthetic valve endocarditis after transcatheter aortic valve implantation

    DEFF Research Database (Denmark)

    Olsen, Niels Thue; De Backer, Ole; Thyregod, Hans G H;

    2015-01-01

    %) were treated conservatively and 1 with surgery. Four patients (22%) died from endocarditis or complications to treatment, 2 of those (11%) during initial hospitalization for PVE. An increased risk of TAVI-PVE was seen in patients with low implanted valve position (hazard ratio, 2.8 [1.1-7.2]), moderate...... or worse postprocedural paravalvular regurgitation (hazard ratio, 4.0 [1.5-11]), implantation of >1 prosthesis (hazard ratio, 5.2 [1.5-18]), and any vascular complication (hazard ratio, 3.8 [1.5-9.8]). CONCLUSIONS: TAVI-PVE occurred at a slightly higher rate than reported for surgically implanted valves...

  19. 31 CFR 235.4 - Check Forgery Insurance Fund.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Check Forgery Insurance Fund. 235.4... SERVICE, DEPARTMENT OF THE TREASURY FINANCIAL MANAGEMENT SERVICE ISSUANCE OF SETTLEMENT CHECKS FOR FORGED CHECKS DRAWN ON DESIGNATED DEPOSITARIES § 235.4 Check Forgery Insurance Fund. The Check Forgery...

  20. Aggressive chemical decontamination tests on small valves from the Garigliano BWR

    International Nuclear Information System (INIS)

    In order to check the effectiveness of direct chemical decontamination on small and complex components, usually considered for storage without decontamination because of the small amount, some tests were performed on the DECO experimental loop. Four small stainless steel valves from the primary system of the Garigliano BWR were decontaminated using mainly aggressive chemicals such as HC1, HF, HNO3 and their mixtures. On two valves, before the treatment with aggressive chemicals, a step with soft chemical (oxalic and citric acid mixture) was performed in order to see whether a softening action enhances the following aggressive decontamination. Moreover, in order to increase as much as possible the decontamination effectiveness, a decontamination process using ultrasounds jointly with aggressive chemicals was investigated. After an intensive laboratory testing programme, two smaller stainless steel valves from the primary system of the Garigliano BWR were decontaminated using ultrasounds in aggressive chemical solutions

  1. Minimally invasive aortic valve replacement

    DEFF Research Database (Denmark)

    Foghsgaard, Signe; Schmidt, Thomas Andersen; Kjaergard, Henrik K

    2009-01-01

    . The 30-day mortality rate for the 98 patients was zero, although 14 of the 98 mini-sternotomies had to be converted to complete sternotomies intraoperatively due to technical problems. Such conversion doubled the operative time over that of the planned full sternotomies. In the group of patients whose......In this descriptive prospective study, we evaluate the outcomes of surgery in 98 patients who were scheduled to undergo minimally invasive aortic valve replacement. These patients were compared with a group of 50 patients who underwent scheduled aortic valve replacement through a full sternotomy...... operations were completed as mini-sternotomies, 4 died later of noncardiac causes. The aortic cross-clamp and perfusion times were significantly different across all groups (P < 0.001), with the intended full-sternotomy group having the shortest times. In conclusion, the mini-aortic valve replacement is an...

  2. Novel Active Combustion Control Valve

    Science.gov (United States)

    Caspermeyer, Matt

    2014-01-01

    This project presents an innovative solution for active combustion control. Relative to the state of the art, this concept provides frequency modulation (greater than 1,000 Hz) in combination with high-amplitude modulation (in excess of 30 percent flow) and can be adapted to a large range of fuel injector sizes. Existing valves often have low flow modulation strength. To achieve higher flow modulation requires excessively large valves or too much electrical power to be practical. This active combustion control valve (ACCV) has high-frequency and -amplitude modulation, consumes low electrical power, is closely coupled with the fuel injector for modulation strength, and is practical in size and weight. By mitigating combustion instabilities at higher frequencies than have been previously achieved (approximately 1,000 Hz), this new technology enables gas turbines to run at operating points that produce lower emissions and higher performance.

  3. 2D SIMPLIFIED SERVO VALVE

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel pilot stage valve called simplified 2D valve, which utilizes both rotary and linear motions of a single spool, is presented.The rotary motion of the spool incorporating hydraulic resistance bridge, formed by a damper groove and a crescent overlap opening, is utilized as pilot to actuate linear motion of the spool.A criterion for stability is derived from the linear analysis of the valve.Special experiments are designed to acquire the mechanical stiffness, the pilot leakage and the step response.It is shown that the sectional size of the spiral groove affects the dynamic response and the stiffness contradictorily and is also very sensitive to the pilot leakage.Therefore, it is necessary to establish a balance between the static and dynamic characteristics in deciding the structural parameters.Nevertheless, it is possible to sustain the dynamic response at a fairly high level, while keeping the leakage of the pilot stage at an acceptable level.

  4. Propellant isolation shutoff valve program

    Science.gov (United States)

    Merritt, F. L.

    1973-01-01

    An analysis and design effort directed to advancing the state-of-the-art of space storable isolation valves for control of flow of the propellants liquid fluorine/hydrazine and Flox/monomethylhydrazine is discussed. Emphasis is on achieving zero liquid leakage and capability of withstanding missions up to 10 years in interplanetary space. Included is a study of all-metal poppet sealing theory, an evaluation of candidate seal configurations, a valve actuator trade-off study and design description of a pneumo-thermally actuated soft metal poppet seal valve. The concepts and analysis leading to the soft seal approach are documented. A theoretical evaluation of seal leakage versus seal loading, related finishes and yield strengths of various materials is provided. Application of a confined soft aluminum seal loaded to 2 to 3 times yield strength is recommended. Use of either an electro-mechanical or pneumatic actuator appears to be feasible for the application.

  5. Bistable diverter valve in microfluidics

    Science.gov (United States)

    Tesař, V.; Bandalusena, H. C. H.

    2011-05-01

    Bistable diverter valves are useful for a large number of no-moving-part flow control applications, and there is a considerable interest in using them also in microfluidics, especially for handling small pressure-driven flows. However, with decreasing Reynolds number, the Coanda effect—on which the flow diverting effect depends—becomes less effective. Authors performed a study, involving flow visualisation, PIV experiments, measurements of the flow rates, and numerical flowfield computations, aimed at clarifying behaviour of a typical fluidic valve at low Reynolds numbers. A typical fluidic valve originally developed for high Re operation was demonstrated to be useful, though with progressively limited efficiency, down to surprisingly low Re values as small as Re = 800. Also observed was a previously not reported discontinuation in the otherwise monotonic decrease in performance at Re between 1,500 and 2,000.

  6. How Is Heart Valve Disease Diagnosed?

    Science.gov (United States)

    ... assess the severity of your heart valve disease. Cardiac MRI Cardiac MRI uses a powerful magnet and radio waves to make detailed images of your heart. A cardiac MRI image can confirm information about valve defects or ...

  7. Regular inspection of safety and relief valves

    International Nuclear Information System (INIS)

    Safety valve concepts with self control mechanisms are in regular use in nuclear power plants in the Federal Republic of Germany. The effect of defects in these valves and the influence on inspection practices is discussed. 12 figs., 1 tab

  8. Cryptorchidism in boys with posterior urethral valves.

    Science.gov (United States)

    Krueger, R P; Hardy, B E; Churchill, B M

    1980-07-01

    A review of 207 male children with poterior urethral valves revealed an over-all incidence of cryptorchidism of 12 per cent. This association of cryptorchidism in boys with posterior urethral valves has not been described previously. PMID:6106069

  9. How Is Heart Valve Disease Treated?

    Science.gov (United States)

    ... is called a valve-in-valve procedure. Heart-Healthy Lifestyle Changes to Treat Other Related Heart Conditions To ... your doctor may advise you to make heart-healthy lifestyle changes, such as: Heart-healthy eating Aiming for ...

  10. SLM Produced Hermetically Sealed Isolation Valve

    Science.gov (United States)

    Richard, James A.

    2014-01-01

    Marshall Space Flight Center (MSFC) has developed a valve concept to replace traditional pyrotechnic driven isolation valves. This paper will describe the valve design and development process. The valve design uses a stem/wedge to support a disk inside the valve. That disk hermetically seals the pressurized fluids. A release mechanism holds the stem/wedge and a large spring in place. When required to open, a solenoid is energized and pulls the release mechanism allowing the spring to pull the stem/wedge away from the disk. Now the disk is unsupported and the pressure ruptures the disk allowing flow to the outlet of the valve. This paper will provide details of this design, describe the development testing, and show the results from the valve level tests performed. Also, a trade study is presented to show the advantages of this design to a conventional pyrotechnic based valve.

  11. Pannus Formation Leads to Valve Malfunction in the Tricuspid Position 19 Years after Triple Valve Replacement.

    Science.gov (United States)

    Alskaf, Ebraham; McConkey, Hannah; Laskar, Nabila; Kardos, Attila

    2016-01-01

    The Medtronic ATS Open Pivot mechanical valve has been successfully used in heart valve surgery for more than two decades. We present the case of a patient who, 19 years following a tricuspid valve replacement with an ATS prosthesis as part of a triple valve operation following infective endocarditis, developed severe tricuspid regurgitation due to pannus formation. PMID:27355145

  12. Semantic rule-checking for regulation compliance checking: an overview of strategies and approaches

    OpenAIRE

    Pauwels, Pieter; Zhang, Sijie

    2015-01-01

    As more and more architectural design and construction data is represented in the Resource Description Framework (RDF) data model, it makes sense to take advantage of the underlying logical basis of RDF and realise a semantic rule-checking process as it is currently not available in architectural design and construction industry. Such a semantic rule-checking process would be of considerable value to regulation compliance checking procedures, because the additional logical basis would (1) all...

  13. MPST Software: grl_pef_check

    Science.gov (United States)

    Call, Jared A.; Kwok, John H.; Fisher, Forest W.

    2013-01-01

    This innovation is a tool used to verify and validate spacecraft sequences at the predicted events file (PEF) level for the GRAIL (Gravity Recovery and Interior Laboratory, see http://www.nasa. gov/mission_pages/grail/main/index. html) mission as part of the Multi-Mission Planning and Sequencing Team (MPST) operations process to reduce the possibility for errors. This tool is used to catch any sequence related errors or issues immediately after the seqgen modeling to streamline downstream processes. This script verifies and validates the seqgen modeling for the GRAIL MPST process. A PEF is provided as input, and dozens of checks are performed on it to verify and validate the command products including command content, command ordering, flight-rule violations, modeling boundary consistency, resource limits, and ground commanding consistency. By performing as many checks as early in the process as possible, grl_pef_check streamlines the MPST task of generating GRAIL command and modeled products on an aggressive schedule. By enumerating each check being performed, and clearly stating the criteria and assumptions made at each step, grl_pef_check can be used as a manual checklist as well as an automated tool. This helper script was written with a focus on enabling the user with the information they need in order to evaluate a sequence quickly and efficiently, while still keeping them informed and active in the overall sequencing process. grl_pef_check verifies and validates the modeling and sequence content prior to investing any more effort into the build. There are dozens of various items in the modeling run that need to be checked, which is a time-consuming and errorprone task. Currently, no software exists that provides this functionality. Compared to a manual process, this script reduces human error and saves considerable man-hours by automating and streamlining the mission planning and sequencing task for the GRAIL mission.

  14. Damage-Free Relief-Valve Disassembly

    Science.gov (United States)

    Haselmaier, H.

    1986-01-01

    Tool safely disassembles relief valves without damage to sensitive parts. Relief-valve disassembly tool used to extract valve nozzle from its housing. Holding device on tool grops nozzle. When user strikes hammer against impact disk, holding device pulls nozzle from press fit. Previously, nozzle dislodged by striking spindle above it, but practice often damaged retaining screw. New tool removes nozzle directly. With minor modifications, tool adapted to valves from different manufacturers.

  15. The Freedom SOLO bovine pericardial stentless valve

    Directory of Open Access Journals (Sweden)

    Stanger O

    2014-12-01

    Full Text Available Olaf Stanger, Hendrik Tevaearai, Thierry Carrel Clinic for Cardiovascular Surgery, University Hospital Berne, Switzerland Abstract: The third-generation bovine pericardium Freedom SOLO (FS stentless valve emerged in 2004 as a modified version of the Pericarbon Freedom stentless valve and as a very attractive alternative to stented bioprostheses. The design, choice of tissue, and anticalcification treatment fulfill most, if not all, requirements for an ideal valve substitute. The FS combines the single-suture, subcoronary implantation technique with the latest-generation bovine pericardial tissue and novel anticalcification treatment. The design allows imitation of the native healthy valve through unrestricted adaption to the patient's anatomy, reproducing a normal valve/root complex. However, despite hemodynamic performance superior to stented valves, we are approaching a critical observation period as superior durability, freedom from structural valve deterioration, and nonstructural failure has not been proven as expected. However, optimal performance and freedom from structural valve deterioration depend on correct sizing and perfect symmetric implantation, to ensure low leaflet stress. Any malpositioning can lead to tissue fatigue over time. Furthermore, the potential for better outcomes depends on optimal patient selection and observance of the limitations for the use of stentless valves, particularly for the FS. Clearly, stentless valve implantation techniques are less reproducible and standardized, and require surgeon-dependent experience and skill. Regardless of whether or not stentless valve durability surpasses third-generation stented bioprostheses, they will continue to play a role in the surgical repertoire. This review intends to help practitioners avoid pitfalls, observe limitations, and improve patient selection for optimal long-term outcome with the attractive FS stentless valve. Keywords: aortic valve, bioprosthesis, cardiac

  16. Infective endocarditis following percutaneous pulmonary valve replacement

    DEFF Research Database (Denmark)

    Cheung, Gary; Vejlstrup, Niels; Ihlemann, Nikolaj;

    2013-01-01

    Infective endocarditis (IE) following percutaneous pulmonary valve replacement (PPVR) with the Melody valve is rarely reported. Furthermore, there are challenges in this diagnosis; especially echocardiographic evidence of vegetation within the prosthesis may be difficult.......Infective endocarditis (IE) following percutaneous pulmonary valve replacement (PPVR) with the Melody valve is rarely reported. Furthermore, there are challenges in this diagnosis; especially echocardiographic evidence of vegetation within the prosthesis may be difficult....

  17. Small sodium valve design and operating experience

    International Nuclear Information System (INIS)

    The United States Liquid Metal Fast Breeder Reactor program (LMFBR) includes an extensive program devoted to the development of small sodium valves. This program is now focused on the development and production of valves for the Fast Flux Test Facility (FFTF) now under construction near Richland, Washington. Other AEC support facilities, such as various test loops located at the Liquid Metal Engineering Center (LMEC), Los Angeles, California, and at the Hanford Engineering Development Laboratory (HEDL), Richland, Washington, also have significant requirements for small sodium valves, and valves similar in design to the FFTF valves are being supplied to these AEC laboratories for use in their critical test installations. A principal motivation for these valve programs, beyond the immediate need to provide high-reliability valves for FFTF and the support facilities, is the necessity to develop small valve technology for the Clinch River Breeder Reactor Plant (CRBRP). FFTF small sodium valve design and development experience will be directly applied to the CRBRP program. Various test programs have been, and are being, conducted to verify the performance and integrity of the FFTF valves, and to uncover any potential problems so that they can be corrected before the valves are placed in service in FFTF. The principal small sodium valve designs being utilized in current U.S. programs, the test and operational experience obtained to date on them, problems uncovered, and future development and testing efforts being planned are reviewed. The standards and requirements to which the valves are being designed and fabricated, the valve designs in current use, valve operators, test and operating experience, and future valve development plans are summarized. (U.S.)

  18. Brucella Endocarditis in Prosthetic Valves

    Science.gov (United States)

    Mehanic, Snjezana; Mulabdic, Velida; Baljic, Rusmir; Hadzovic-Cengic, Meliha; Pinjo, Fikret; Hadziosmanovic, Vesna; Topalovic, Jasna

    2012-01-01

    SUMMARY CONFLICT OF INTEREST: none declared. Introduction Brucella endocarditis (BE) is a rare but severe and potentially lethal manifestation of brucellosis. Pre-existing valves lesions and prosthetic valves (PV) are favorable for BE. Case report We represent the case of a 46-year-old man who was treated at the Clinic for Infectious Diseases, Clinical Center of Sarajevo University, as blood culture positive (Brucella melitensis) mitral and aortic PV endocarditis. He was treated with combined anti-brucella and cardiac therapy. Surgical intervention was postponed due to cardiac instability. Four months later he passed away. Surgery was not performed. PMID:24493988

  19. Effects of the blockage ratio of a valve disk on loss coefficient in a butterfly valve

    International Nuclear Information System (INIS)

    The loss coefficient of the butterfly valve which allows partial opening of the valve at closed position and is applicable to the small-sized pipe system with the diameter of 1 inch was measured for the variation of the valve disk blockage ratio. Two different types of the valve disk configuration to adjust the blockage ratio were considered. One was the solid type valve disk of which the diameter was changed into the smaller size rather than the pipe diameter, and the other was the perforate type valve disk on which some holes were perforated. The results from two types of valve disk were compared to identify their characteristics in the loss coefficient distributions. The loss coefficient and the controllable angle of the valve disk were decreased exponentially with the decrease of the blockage ratio. In addition, the perforate valve disk had the effect on the higher loss coefficient rather than the solid type valve disk

  20. Aortic valve annuloplasty: new single suture technique.

    Science.gov (United States)

    Schöllhorn, Joachim; Rylski, Bartosz; Beyersdorf, Friedhelm

    2014-06-01

    Reconstruction strategies for aortic valve insufficiency in the presence of aortic annulus dilatation are usually surgically challenging. We demonstrate a simple, modified Taylor technique of downsizing and stabilization of the aortic annulus using a single internal base suture. Since April 2011, 22 consecutive patients have undergone safe aortic valve annuloplasty. No reoperations for aortic valve insufficiency and no deaths occurred. PMID:24882316

  1. 49 CFR 192.145 - Valves.

    Science.gov (United States)

    2010-10-01

    ...) Except for cast iron and plastic valves, each valve must meet the minimum requirements of API 6D... at least 1.5 times the maximum service rating. (ii) After the shell test, the seat must be tested to... valves, test pressure during the seat test must be applied successively on each side of the closed...

  2. Aspirator increases relief valve poppet stroke

    Science.gov (United States)

    Biddle, M. E.

    1967-01-01

    Addition of an aspirator to a relief valve increases the valve poppet stroke under dynamic flow conditions. The aspirator allows poppet inlet dynamic forces to overcome relief valve spring force. It reduces the fluid pressure in the skirt cavity by providing a low pressure sense probe.

  3. 46 CFR 64.67 - Shutoff valve.

    Science.gov (United States)

    2010-10-01

    ... SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.67 Shutoff valve. A shutoff valve may not be located— (a) Between the tank opening and pressure relief device; or (b) On the discharge... 46 Shipping 2 2010-10-01 2010-10-01 false Shutoff valve. 64.67 Section 64.67 Shipping COAST...

  4. Aerodynamic Characteristics of Tracheostomy Speaking Valves.

    Science.gov (United States)

    Fornataro-Clerici, Lisa; Zajac, David J.

    1993-01-01

    Pressure-flow characteristics were determined for four different one-way valves (Kisner, Montgomery, Olympic, and Passy-Muir) used for speech production in tracheotomy patients. Results indicated significant differences in resistance among the valves, with the resistance of one valve substantially greater than that of the normal upper airways.…

  5. A PSL Bounded Model Checking Method

    Institute of Scientific and Technical Information of China (English)

    YU Lei; ZHAO Zongtao

    2012-01-01

    SAT-based bounded model checking (BMC) is introduced as an important complementary technique to OBDD-based symbolic model checking, and is an efficient verification method for parallel and reactive systems. However, until now the properties verified by bounded model checking are very finite. Temporal logic PSL is a property specification language (IEEE-1850) describing parallel systems and is divided into two parts, i.e. the linear time logic FL and the branch time logic OBE. In this paper, the specification checked by BMC is extended to PSL and its algorithm is also proposed. Firstly, define the bounded semantics of PSL, and then reduce the bounded semantics into SAT by translating PSL specification formula and the state transition relation of the system to the propositional formula A and B, respectively. Finally, verify the satisfiability of the conjunction propositional formula of A and B. The algorithm results in the translation of the existential model checking of the temporal logic PSL into the satisfiability problem of propositional formula. An example of a queue controlling circuit is used to interpret detailedly the executing procedure of the algorithm.

  6. Check Point任命新总裁

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    近日,互联网安全解决方案供应商Check Point软件技术有限公司宣布,Amnon Bar—Lev晋升为公司总裁。Bar--Lev将继续掌管公司面向客户的工作,包括销售、市场营销、业务发展、技术服务和合作伙伴计划。Bar—Lev于2005年加入Check Point,担任技术服务副总裁,并于2006年开始领导全球市场运营。在此期间,Check Point营业额增长了1倍多,达到约12亿美元。

  7. HCH for Checking Containment of XPath Fragment

    Institute of Scientific and Technical Information of China (English)

    Jian-Hua Feng; Yu-Guo Liao; Yong Zhang

    2007-01-01

    XPath is ubiquitous in XML applications for navigating XML trees and selecting a set of element nodes. In XPath query processing, one of the most important issues is how to efficiently check containment relationship between two XPath expressions. To get out of the intricacy and complexity caused by numerous XPath features, we investigate this issue on a frequently used fragment of XPath expressions that consists of node tests, the child axis (/), the descendant axis (//), branches ([]) and label wildcards (*). Prior work has shown that homomorphism technology can be used for containment checking. However, homomorphism is the sufficient but not necessary condition for containment. For special classes of this fragment, the homomorphism algorithm returns false negatives. To address this problem, this paper proposes two containment techniques, conditioned homomorphism and hidden conditioned homomorphism, and then presents sound algorithms for checking containment. Experimental results confirm the practicability and efficiency of the proposed algorithms.

  8. Quality checking of radioactive and hazardous waste

    International Nuclear Information System (INIS)

    This report describes the work of the HMIP Waste Quality Checking Laboratory (WQCL) for the period September 1989 -August 1991. The WQCL has conducted research and development of procedures for the receipt, sampling and analysis of low level solid radioactive waste (LLW), intermediate level radioactive waste (ILW) and hazardous chemical waste (HW). Operational facilities have been commissioned for quality checking both LLW and HW. Waste quality checking has been completed on LLW packages seized from the UK waste disposal route by HMIP Inspectors. Packages have ranged in size from the 200 litre steel drum to half-height ISO freight container. Development work was continued on methods of sample extraction and radio-chemical analysis for cement encapsulated ILW in the form of magnox, graphite and stainless steel. This work was undertaken on non-radioactive simulants. (author)

  9. Checking Timed Automata for Linear Duration Properties

    Institute of Scientific and Technical Information of China (English)

    赵建华

    2000-01-01

    It is proved in this paper that checking a timed automaton M with respect to a linear duration property D can be done by investigating only the integral timed states of M. An equivalence relation is introduced in this paper to divide the infinite number of integral timed states into finite number of equivalence classes. Based on this, a method is proposed for checking whether M satisfies D. In some cases, the number of equivalence classes is too large for a computer to manipulate. A technique for reducing the search-space for checking linear duration property is also described. This technique is more suitable for the case in this paper than those in the literature because most of those techniques are designed for reachability analysis.

  10. Constraint LTL Satisfiability Checking without Automata

    CERN Document Server

    Bersani, Marcello M; Morzenti, Angelo; Pradella, Matteo; Rossi, Matteo; Pietro, Pierluigi San

    2012-01-01

    This paper introduces a novel technique to decide the satisfiability of formulae written in the language of Linear Temporal Logic with Both future and past operators and atomic formulae belonging to constraint system D (CLTLB(D) for short). The technique is based on the concept of bounded satisfiability, and hinges on an encoding of CLTLB(D) formulae into QF-EUD, the theory of quantifier-free equality and uninterpreted functions combined with D. Similarly to standard LTL, where bounded model-checking and SAT-solvers can be used as an alternative to automata-theoretic approaches to model-checking, our approach allows users to solve the satisfiability problem for CLTLB(D) formulae through SMT-solving techniques, rather than by checking the emptiness of the language of a suitable automaton A{\\phi}. The technique is effective, and it has been implemented in our Zot formal verification tool.

  11. A Metric Encoding for Bounded Model Checking

    Science.gov (United States)

    Pradella, Matteo; Morzenti, Angelo; San Pietro, Pierluigi

    In Bounded Model Checking, both the system model and the checked property are translated into a Boolean formula to be analyzed by a SAT-solver. We introduce a new encoding technique which is particularly optimized for managing quantitative future and past metric temporal operators, typically found in properties of hard real time systems. The encoding is simple and intuitive in principle, but it is made more complex by the presence, typical of the Bounded Model Checking technique, of backward and forward loops used to represent an ultimately periodic infinite domain by a finite structure. We report and comment on the new encoding technique and on an extensive set of experiments carried out to assess its feasibility and effectiveness.

  12. Graded CTL Model Checking for Test Generation

    CERN Document Server

    Napoli, Margherita

    2011-01-01

    Recently there has been a great attention from the scientific community towards the use of the model-checking technique as a tool for test generation in the simulation field. This paper aims to provide a useful mean to get more insights along these lines. By applying recent results in the field of graded temporal logics, we present a new efficient model-checking algorithm for Hierarchical Finite State Machines (HSM), a well established symbolism long and widely used for representing hierarchical models of discrete systems. Performing model-checking against specifications expressed using graded temporal logics has the peculiarity of returning more counterexamples within a unique run. We think that this can greatly improve the efficacy of automatically getting test cases. In particular we verify two different models of HSM against branching time temporal properties.

  13. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... polyester material that's used for -- it's basically a medical grade fabric. And again, I want to underscore that these tissue valves are hand-made in factories and undergo quite a bit of testing and tolerance before they ever reach our shelf. ...

  14. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... made out of either tissues from cows or pigs, what we call porcine for pigs and bovine for cows. Essentially, the tissue from ... we generally recommend explantation and reimplantation of a sterile valve. Again, I want to underscore that any ...

  15. Hemodynamics driven cardiac valve morphogenesis.

    Science.gov (United States)

    Steed, Emily; Boselli, Francesco; Vermot, Julien

    2016-07-01

    Mechanical forces are instrumental to cardiovascular development and physiology. The heart beats approximately 2.6 billion times in a human lifetime and heart valves ensure that these contractions result in an efficient, unidirectional flow of the blood. Composed of endocardial cells (EdCs) and extracellular matrix (ECM), cardiac valves are among the most mechanically challenged structures of the body both during and after their development. Understanding how hemodynamic forces modulate cardiovascular function and morphogenesis is key to unraveling the relationship between normal and pathological cardiovascular development and physiology. Most valve diseases have their origins in embryogenesis, either as signs of abnormal developmental processes or the aberrant re-expression of fetal gene programs normally quiescent in adulthood. Here we review recent discoveries in the mechanobiology of cardiac valve development and introduce the latest technologies being developed in the zebrafish, including live cell imaging and optical technologies, as well as modeling approaches that are currently transforming this field. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel. PMID:26608609

  16. Hydraulic servo control spool valve

    Science.gov (United States)

    Miller, Donald M.

    1983-01-01

    A servo operated spool valve having a fixed sleeve and axially movable spool. The sleeve is machined in two halves to form a long, narrow tapered orifice slot across which a transverse wall of the spool is positioned. The axial position of the spool wall along the slot regulates the open orifice area with extreme precision.

  17. Dual rate pressure relief valve

    Science.gov (United States)

    Steeneken, J.

    1968-01-01

    Pressure relief valve vents at a slow bleed rate at one pressure level and at a higher bleed rate at a higher pressure level. The value housing contains a sleeve, inlet port, outlet port, an orifice, a ball and seat arrangement, and a belleville spring diaphragm.

  18. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... to know the human dynamic or blood pressure effects of a valvular problem and is also important with regards to determining coronary artery anatomy, as some patients may need coronary bypass surgery in addition to valve surgery. Exercise testing, as I mentioned previously, is a nice ...

  19. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... rid of that issue. These are inert valvular prosthetics, both the tissue and mechanical prostheses are. Not to say that some destruction ... lifelong risk of infection. And obviously if a prosthetic valve, whether it be tissue or mechanical, were to become infected, we generally recommend explantation ...

  20. Gate-Check System for Outotec Company

    OpenAIRE

    Zajac, Lukas; Bartusek, Petr

    2014-01-01

    The main purpose of the thesis was to create the interactive, electronic web application Gate-Check for Outotec Company, which replaced the old system based on MS Excel document. Another purpose was gaining new skills and experiences in communication with the company, in which the team acted as a Supply Company. The created web application (Gate-Check System) should be compatible with any device with integrated web browser with support HTML5, JavaScript and CSS3 and active internet connect...

  1. Engineering Abstractions in Model Checking and Testing

    DEFF Research Database (Denmark)

    Achenbach, Michael; Ostermann, Klaus

    2009-01-01

    Abstractions are used in model checking to tackle problems like state space explosion or modeling of IO. The application of these abstractions in real software development processes, however, lacks engineering support. This is one reason why model checking is not widely used in practice yet and...... testing is still state of the art in falsification. We show how user-defined abstractions can be integrated into a Java PathFinder setting with tools like AspectJ or Javassist and discuss implications of remaining weaknesses of these tools. We believe that a principled engineering approach to designing...

  2. A Systematic Review of the Empirical Support for Check-in Check-Out

    Science.gov (United States)

    Wolfe, Katie; Pyle, Daniel; Charlton, Cade T.; Sabey, Christian V.; Lund, Emily M.; Ross, Scott W.

    2016-01-01

    Tier 2 interventions play an important role within the Positive Behavioral Interventions and Supports framework, bridging the gap between schoolwide Tier 1 interventions and individualized Tier 3 supports. Check-in Check-out (CICO) is a promising Tier 2 intervention for addressing mild problem behavior and potentially preventing the need for more…

  3. Function-Based Modification of Check-In/Check-Out to Influence Escape-Maintained Behavior

    Science.gov (United States)

    Kilgus, Stephen P.; Fallon, Lindsay M.; Feinberg, Adam B.

    2016-01-01

    Prior research has suggested Check-In/Check-Out (CICO) effectiveness is linked to the function of problem behavior. Though effective for students whose misbehavior occurs to gain attention, findings are equivocal for behavior that occurs to escape academic tasks. The purpose of this study was to therefore evaluate a modification to CICO, wherein…

  4. Valve assembly having remotely replaceable bearings

    Science.gov (United States)

    Johnson, Evan R.; Tanner, David E.

    1980-01-01

    A valve assembly having remotely replaceable bearings is disclosed wherein a valve disc is supported within a flow duct for rotation about a pair of axially aligned bearings, one of which is carried by a spindle received within a diametral bore in the valve disc, and the other of which is carried by a bearing support block releasably mounted on the duct circumferentially of an annular collar on the valve disc coaxial with its diametrical bore. The spindle and bearing support block are adapted for remote removal to facilitate servicing or replacement of the valve disc support bearings.

  5. Closing valve, especially for large diameter pipes

    International Nuclear Information System (INIS)

    A closing valve is described designed for use in large diameter pipes for the transport of dangerous and harmful media in nuclear power facilities. The valve assembly consists of a leak-proof cover, a double-side spindle closure and two parallel seats placed in the through-flow axis of the valve body. The design of the valve spindle closure allows closing pipe mains of large diameter at high operating pressures without the danger of disturbing the tightness of the valve. (J.B.)

  6. Multifunctional four-port directional control valve constructed from logic valves

    International Nuclear Information System (INIS)

    Highlights: • Directional valve with standard ISO 440-08 has been constructed from logic valves. • Only one innovative valve may replace whole family of the standard valves. • CFD analysis and bench tests of the innovative valve has been carried. • Parameters of the innovative valve are equaling or surpassing the standard ones. • The innovative valve has additional possibilities of pressure and flow control. - Abstract: The paper refers to four-port solenoid pilot operated valves, which are subplate mounted in a hydraulic system in accordance with the ISO 4401 standard. Their widespread use in many machines and devices causes a continuing interest in the development of their design by both the scientific centers and the industry. This paper presents an innovative directional control valve based on the use of logic valves and a methodology followed for the design of it by using Solid Edge CAD and ANSYS/Fluent CFD software. The valve design methodology takes into account the need to seek solutions that minimize flow resistance through the valve. For this purpose, the flow paths are prepared by means of CAD software and pressure-flow curves are determined as a result of CFD analysis. The obtained curves are compared with the curves available in the catalogs of spool type directional control valves. The new solution allows to replace the whole family of spool type four-port directional control valves by one valve built of logic valves. In addition, the innovative directional control valve provides leak-proof shutting the flow paths off and also it can control flow rate and even pressure of working liquid. A prototype of the valve designed by the presented method has been made and tested on the test bench. The results quoted in the paper confirm that the developed logic type directional control valve is able to meet all designed connection configurations, and the obtained pressure-flow curves show very good conformity with the results of CFD analysis

  7. Mitral Valve Repair: The Chordae Tendineae

    Directory of Open Access Journals (Sweden)

    Carlos-A Mestres

    2015-10-01

    Full Text Available Repair of the mitral valve is the treatment of choice for mitral valve regurgitation when the anatomy is favorable. It is well known that mitral valve repair enjoys better clinical and functional results than any other type of valve substitute. This fact is beyond doubt regardless of the etiology of the valve lesion and is of particular importance in degenerative diseases.This review analyzes the most important advances in the knowledge of the anatomy, pathophysiology, and chordal function of the mitral valve as well as the different alternatives in the surgical repair and clinical results of the most prevalent diseases of the mitral valve. An attempt has been made to organize the acquired information available in a practical way.

  8. Design of a class 1 safety valve

    International Nuclear Information System (INIS)

    Spring-loaded safety valves are used to protect the over-pressurization of fluid systems or pressure vessels. The valves are required to open for the pressure mitigation and reseat after the system pressure is reduced to a certain value. Due to its critical role in power plants, the structural integrity of the valve is highly demanded. In nuclear power application, the design of the valve is required to comply with the provisions in the codes and standards. In many countries, nuclear service safety valves are designed to the requirements of ASME Section III. In Korea, KEPIC (Korea Electric Power Industry Code) as well as ASME Section III is accepted as the standards for the design and manufacturing of nuclear equipment as specified in the Notice No. 2000-17 of the MOST (Ministry of Science and Technology). To date, the maintenance of safety related valves has been principally relied on by overseas technology, if significant failure was found during the valve operation. This is mainly due to the fact that nuclear service safety valves were not developed domestically until a recent date. In the last two years, KEPRI has developed a MSSV (Main Steam Safety Valve) in cooperation with Jokwang I.L.I. Co. In the design process, the structural adequacy of the valve was assessed as a safety Class 1 valve by principally relying on the FE (Finite Element) technique. Actually, the valve can be designed to the requirement of a Class 2 valve. In spite of the industrial interest, there are few design materials which could be referred to. Therefore, delineation of a design procedure for nuclear equipment is claimed. To this end, the assessment procedure for the safety valve structure is discussed in the present study based on KEPIC MNB (or ASME Section III NB)

  9. Pulmonary valve regurgitation following balloon valvuloplasty for pulmonary valve stenosis: Single center experience

    Directory of Open Access Journals (Sweden)

    Asim Yousuf Al Balushi

    2013-01-01

    Full Text Available Background: Pulmonary valve regurgitation following balloon valvuloplasty for moderate to severe pulmonary valve stenosis is a known late outcome of this procedure. Objective: The aim of the study was to characterise the status of pulmonary regurgitation on follow up after pulmonary valve balloon dilatation (PVBD, and to study the determinant of the severity of PR. Materials and Methods: We retrospectively reviewed 50 consecutive patients, aged 2 days to 18 years, with isolated pulmonary valve stenosis, who had undergone PVBD in 2004-2009 and were assessed with follow-up Doppler echocardiography. The impact of balloon to annulus ratio, age, and valve anatomy on the late development of moderate and severe pulmonary valve regurgitation following balloon valvuloplasty was analysed. Results: Six patients (12% had no pulmonary valve regurgitation; 32 (64% had mild, 9 (18% had moderate, and 3 (6% had severe pulmonary valve regurgitation at a mean follow-up of 4 years. Balloon to annulus ratio, age, and valve anatomy were not statistically significant predictors for moderate and severe pulmonary valve regurgitation. Conclusions: The majority of patients in our population had mild pulmonary valve regurgitation. Moderate to severe pulmonary valve regurgitation was well tolerated at midterm follow-up. Age, balloon to annulus ratio, and valve anatomy were not statistically significant predictors for the late development of moderate and severe valve regurgitation. Large and longer follow-up studies are needed to address this question.

  10. Conical Seat Shut-Off Valve

    Science.gov (United States)

    Farner, Bruce

    2013-01-01

    A moveable valve for controlling flow of a pressurized working fluid was designed. This valve consists of a hollow, moveable floating piston pressed against a stationary solid seat, and can use the working fluid to seal the valve. This open/closed, novel valve is able to use metal-to-metal seats, without requiring seat sliding action; therefore there are no associated damaging effects. During use, existing standard high-pressure ball valve seats tend to become damaged during rotation of the ball. Additionally, forces acting on the ball and stem create large amounts of friction. The combination of these effects can lead to system failure. In an attempt to reduce damaging effects and seat failures, soft seats in the ball valve have been eliminated; however, the sliding action of the ball across the highly loaded seat still tends to scratch the seat, causing failure. Also, in order to operate, ball valves require the use of large actuators. Positioning the metal-to-metal seats requires more loading, which tends to increase the size of the required actuator, and can also lead to other failures in other areas such as the stem and bearing mechanisms, thus increasing cost and maintenance. This novel non-sliding seat surface valve allows metal-to-metal seats without the damaging effects that can lead to failure, and enables large seating forces without damaging the valve. Additionally, this valve design, even when used with large, high-pressure applications, does not require large conventional valve actuators and the valve stem itself is eliminated. Actuation is achieved with the use of a small, simple solenoid valve. This design also eliminates the need for many seals used with existing ball valve and globe valve designs, which commonly cause failure, too. This, coupled with the elimination of the valve stem and conventional valve actuator, improves valve reliability and seat life. Other mechanical liftoff seats have been designed; however, they have only resulted in

  11. Anchor Stress Checking of Security Injection Tank

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The intention of the calculating is to check the anchor stresses of the security injection tank to know whether the stress is satisfied the code requirements on the basis of all the reaction forces gained in the static, seismic and thermal stress results.

  12. Statistical Model Checking for Biological Systems

    DEFF Research Database (Denmark)

    David, Alexandre; Larsen, Kim Guldstrand; Legay, Axel;

    2014-01-01

    Statistical Model Checking (SMC) is a highly scalable simulation-based verification approach for testing and estimating the probability that a stochastic system satisfies a given linear temporal property. The technique has been applied to (discrete and continuous time) Markov chains, stochastic...

  13. A Method for Model Checking Feature Interactions

    DEFF Research Database (Denmark)

    Pedersen, Thomas; Le Guilly, Thibaut; Ravn, Anders Peter; Skou, Arne Joachim

    This paper presents a method to check for feature interactions in a system assembled from independently developed concurrent processes as found in many reactive systems. The method combines and refines existing definitions and adds a set of activities. The activities describe how to populate the ...

  14. Using chemical organization theory for model checking

    OpenAIRE

    Kaleta, Christoph; Richter, Stephan; Dittrich, Peter

    2009-01-01

    Motivation: The increasing number and complexity of biomodels makes automatic procedures for checking the models' properties and quality necessary. Approaches like elementary mode analysis, flux balance analysis, deficiency analysis and chemical organization theory (OT) require only the stoichiometric structure of the reaction network for derivation of valuable information. In formalisms like Systems Biology Markup Language (SBML), however, information about the stoichiometric coefficients re...

  15. Efficient CSL Model Checking Using Stratification

    DEFF Research Database (Denmark)

    Zhang, Lijun; Jansen, David N.; Nielson, Flemming; Hermanns, Holger

    2012-01-01

    For continuous-time Markov chains, the model-checking problem with respect to continuous-time stochastic logic (CSL) has been introduced and shown to be decidable by Aziz, Sanwal, Singhal and Brayton in 1996 [ 1, 2]. Their proof can be turned into an approximation algorithm with worse than...

  16. Automata-Based CSL Model Checking

    DEFF Research Database (Denmark)

    Zhang, Lijun; Jansen, David N.; Nielson, Flemming; Hermanns, Holger

    For continuous-time Markov chains, the model-checking problem with respect to continuous-time stochastic logic (CSL) has been introduced and shown to be decidable by Aziz, Sanwal, Singhal and Brayton in 1996. The presented decision procedure, however, has exponential complexity. In this paper, we...

  17. Type checking with open type functions

    DEFF Research Database (Denmark)

    Schrijvers, Tom; Jones, Simon Peyton; Chakravarty, Manual; Sulzmann, Martin

    We report on an extension of Haskell with open type-level functions and equality constraints that unifies earlier work on GADTs, functional dependencies, and associated types. The contribution of the paper is that we identify and characterise the key technical challenge of entailment checking; and...

  18. Availability of a Renewable, Checked System

    DEFF Research Database (Denmark)

    Platz, O.

    1976-01-01

    Recurrent expressions are given for point and interval unavailability of a renewable system subjected to periodic checking/repair. The expressions are generalizations of the basic relations in the theory of discrete renewal processes. The asymptotic limits for long times follow simply from a...

  19. The common agricultural policy health check

    OpenAIRE

    Erjavec, Emil; Lovec, Marko

    2016-01-01

    In 2008, the ministers of agriculture of European Union member states made a political agreement on the Common Agricultural Policy reform, also known as the Health Check. The reform coincided with three things: the ongoing Doha round of the World Trade Organization negotiations

  20. CT and MR imaging of the mitral valve: radiologic-pathologic correlation.

    Science.gov (United States)

    Morris, Michael F; Maleszewski, Joseph J; Suri, Rakesh M; Burkhart, Harold M; Foley, Thomas A; Bonnichsen, Crystal R; Anavekar, Nandan S; Young, Phillip M; Williamson, Eric E; Glockner, James F; Araoz, Philip A

    2010-10-01

    Computed tomography (CT) and magnetic resonance (MR) imaging are increasingly important adjuncts to echocardiography for the evaluation of mitral valve disease. The mitral valve may be involved in various acquired or congenital conditions with resultant regurgitation or stenosis, and many of these conditions can be identified with CT or MR imaging. In addition, CT is useful for detecting and monitoring postoperative complications after mitral valve repair or replacement. As the use of CT and MR imaging increases, awareness of the CT and MR imaging appearances of the normal mitral valve and the various disease processes that affect it may foster recognition of unsuspected mitral disease in patients undergoing imaging for other purposes. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.306105518/-/DC1. PMID:21071378

  1. Transcatheter aortic valve prosthesis surgically replaced 4 months after implantation

    DEFF Research Database (Denmark)

    Thyregod, Hans Gustav; Lund, Jens Teglgaard; Engstrøm, Thomas;

    2010-01-01

    Transcatheter aortic valve implantation is a new and rapidly evolving treatment option for high-risk surgical patients with degenerative aortic valve stenosis. Long-term results with these new valve prostheses are lacking, and potential valve dysfunction and failure would require valve replacemen....... We report the first case of surgical valve replacement in a patient with a dysfunctional transcatheter-implanted aortic valve prosthesis 4 months after implantation....

  2. Maintenance management for nuclear power plant 'Integrated valve maintenance'

    International Nuclear Information System (INIS)

    The deregulation of Europe's power market does force many utilities, and especially nuclear power plant operators, to introduce extensive cost-cutting measures in order to be able to compete within this new environment. The optimization of plant outages provides considerable potential for raising plant availability but can also lower operating costs by reducing e.g. expenditure on maintenance. Siemens Nuclear Power GmbH, in cooperation with plant operators, is currently implementing new and improved service concepts which can have a major effect on the way in which maintenance will be performed in the future. Innovative service packages for maintenance in nuclear power plants are available which can be used to perform a time- and cost-effective maintenance. The concepts encompass optimization of the overall sequence from planning in advance to the individual measures including reduction of the scope of maintenance activities, identification of cost cutting potential and bundling of maintenance activities. The main features of these maintenance activities are illustrated here using the examples of outage planning and integrated valve maintenance. In nuclear power plants approx. 5000 valves are periodically preventively, condition-based or breakdown-based maintained. Because of this large number of valves to be maintained a high potential of improvements and cost reductions can be achieved by performing an optimized, cost-effective maintenance based on innovative methods and tools. Siemens Nuclear Power GmbH has developed and qualified such tools which allow to reduce service costs while maintaining high standards of safety and availability. By changing from preventive to predictive (condition-based) maintenance - the number of valves to be maintained may be reduced considerably. The predictive maintenance is based on the Siemens Nuclear Power GmbH diagnostic and evaluation method (ADAM). ADAM is used to monitor the operability of valves by analytical verification of

  3. Fault diagnosis of reciprocating compressor valve with the method integrating acoustic emission signal and simulated valve motion

    Science.gov (United States)

    Wang, Yuefei; Xue, Chuang; Jia, Xiaohan; Peng, Xueyuan

    2015-05-01

    This paper proposes a method of diagnosing faults in reciprocating compressor valves using the acoustic emission signal coupled with the simulated valve motion. The actual working condition of a valve can be obtained by analyzing the acoustic emission signal in the crank angle domain and the valve movement can be predicted by simulating the valve motion. The exact opening and closing locations of a normal valve, provided by the simulated valve motion, can be used as references for the valve fault diagnosis. The typical valve faults are diagnosed to validate the feasibility and accuracy of the proposed method. The experimental results indicate that this method can easily distinguish the normal valve, valve flutter and valve delayed closing conditions. The characteristic locations of the opening and closing of the suction and discharge valves can be clearly identified in the waveform of the acoustic emission signal and the simulated valve motion.

  4. 40 CFR 86.327-79 - Quench checks; NOX analyzer.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Quench checks; NOX analyzer. 86.327-79... Quench checks; NOX analyzer. (a) Perform the reaction chamber quench check for each model of high vacuum... capillary, and if used, dilution capillary. (c) Quench check as follows: (1) Calibrate the NOX analyzer...

  5. Transcatheter Aortic Valve Replacement in Bicuspid Aortic Valve Disease

    DEFF Research Database (Denmark)

    Mylotte, Darren; Lefevre, Thierry; Søndergaard, Lars;

    2014-01-01

    .7%; type 1 BAV was 68.3%; and type 2 BAV was 5.0%. Multislice computed tomography (MSCT)-based TAV sizing was used in 63.5% of patients (77.1% balloon-expandable THV vs. 56.0% self-expandable THV, p = 0.02). Procedural mortality was 3.6%, with TAV embolization in 2.2% and conversion to surgery in 2.2%. The......BACKGROUND: Limited information exists describing the results of transcatheter aortic valve (TAV) replacement in patients with bicuspid aortic valve (BAV) disease (TAV-in-BAV). OBJECTIVES: This study sought to evaluate clinical outcomes of a large cohort of patients undergoing TAV-in-BAV. METHODS......: We retrospectively collected baseline characteristics, procedural data, and clinical follow-up findings from 12 centers in Europe and Canada that had performed TAV-in-BAV. RESULTS: A total of 139 patients underwent TAV-in-BAV with the balloon-expandable transcatheter heart valve (THV) (n = 48) or...

  6. Emergency Transcatheter Aortic Valve Implantation for Acute and Early Failure of Sutureless Perceval Aortic Valve.

    Science.gov (United States)

    Durand, Eric; Tron, Christophe; Eltchaninoff, Hélène

    2015-09-01

    We report the case of a 78-year-old woman admitted for cardiogenic shock related to acute and early failure (severe aortic regurgitation) of a Perceval sutureless aortic bioprosthesis (Sorin Group, Saluggia, Italy). Clinical stability was achieved using rescue transfemoral transcatheter aortic valve-in-valve implantation with an Edwards SAPIEN 3 prosthesis (Edwards Lifesciences, Irvine, CA). To our knowledge, we report herein the first case of successful valve-in-valve implantation using a SAPIEN 3 transcatheter heart valve in a sutureless bioprosthetic aortic valve with acute and early deterioration. PMID:26095935

  7. Performance of balanced bellows safety relief valves

    International Nuclear Information System (INIS)

    By the nature of its design, the set point and lift of a conventional spring loaded safety relief valve are sensitive to back pressure. One way to reduce the adverse effects of the back pressure on the safety relief valve function is to install a balanced bellows in a safety relief valve. The metallic bellows has a rather wide range of manufacturing tolerance which makes the design of the bellows safety relief valve very complicated. The state-of-the-art balanced bellows safety relief valve can only substantially minimize, but cannot totally eliminate the back pressure effects on its set point and relieving capacity. Set point change is a linear function of the back pressure to the set pressure ratio. Depending on the valve design, the set point correction factor can be either greater or smaller than unity. There exists an allowable back pressure and critical back pressure for each safety relief valve. When total back pressure exceeds the Ra, the relieving capacity will be reduced mainly resulting from the valve lift being reduced by the back pressure and the capacity reduction factor should be applied in valve sizing. Once the Rc is exceeded, the safety relief valve becomes unstable and loses its over pressure protection capability. The capacity reduction factor is a function of system overpressure, but their relationship is non-linear in nature. (orig.)

  8. Thermostatic Valves Containing Silicone-Oil Actuators

    Science.gov (United States)

    Bhandari, Pradeep; Birur, Gajanana C.; Bame, David P.; Karlmann, Paul B.; Prina, Mauro; Young, William; Fisher, Richard

    2009-01-01

    Flow-splitting and flow-mixing thermally actuated spool valves have been developed for controlling flows of a heat-transfer fluid in a temperature-regulation system aboard the Mars Science Laboratory (MSL) rover. Valves like these could also be useful in terrestrial temperature-regulation systems, including automobile air-conditioning systems and general refrigeration systems. These valves are required to provide smoother actuation over a wider temperature range than the flow-splitting, thermally actuated spool valves used in the Mars Explorer Rover (MER). Also, whereas the MER valves are unstable (tending to oscillate) in certain transition temperature ranges, these valves are required not to oscillate. The MER valves are actuated by thermal expansion of a wax against spring-loaded piston rods (as in common automotive thermostats). The MSL valves contain similar actuators that utilize thermal expansion of a silicone oil, because silicone-oil actuators were found to afford greater and more nearly linear displacements, needed for smoother actuation, over the required wider temperature range. The MSL valves also feature improved spool designs that reflect greater understanding of fluid dynamics, consideration of pressure drops in valves, and a requirement for balancing of pressures in different flow branches.

  9. Emodnet Med Sea Check-Point - Indicators for decision- maker

    Science.gov (United States)

    Besnard, Sophie; Claverie, Vincent; Blanc, Frédérique

    2015-04-01

    The Emodnet Checkpoint projects aim is to assess the cost-effectiveness, reliability and utility of the existing monitoring at the sea basin level. This involves the development of monitoring system indicators and a GIS Platform to perform the assessment and make it available. Assessment or production of Check-Point information is made by developing targeted products based on the monitoring data and determining whether the products are meeting the needs of industry and public authorities. Check-point users are the research community, the 'institutional' policy makers for IMP and MSFD implementation, the 'intermediate users', i.e., users capable to understand basic raw data but that benefit from seeing the Checkpoint targeted products and the assessment of the fitness for purpose. We define assessment criteria aimed to characterize/depict the input datasets in terms of 3 territories capable to show performance and gaps of the present monitoring system, appropriateness, availability and fitness for purpose. • Appropriateness: What is made available to users? What motivate/decide them to select this observation rather than this one. • Availability: How this is made available to the user? Place to understand the readiness and service performance of the EU infrastructure • Fitness for use / fitness for purpose: Ability for non-expert user to appreciate the data exploitability (feedback on efficiency & reliability of marine data) For each territory (appropriateness, Availability and Fitness for purpose / for use), we define several indicators. For example, for Availability we define Visibility, Accessibility and Performance. And Visibility is itself defined by "Easily found" and "EU service". So these indicators can be classified according to their territory and sub-territory as seen above, but also according to the complexity to build them. Indicators are built from raw descriptors in 3 stages:  Stage 1: to give a neutral and basic status directly computed from

  10. [MINIMALLY INVASIVE AORTIC VALVE REPLACEMENT].

    Science.gov (United States)

    Tabata, Minoru

    2016-03-01

    Minimally invasive aortic valve replacement (MIAVR) is defined as aortic valve replacement avoiding full sternotomy. Common approaches include a partial sternotomy right thoracotomy, and a parasternal approach. MIAVR has been shown to have advantages over conventional AVR such as shorter length of stay and smaller amount of blood transfusion and better cosmesis. However, it is also known to have disadvantages such as longer cardiopulmonary bypass and aortic cross-clamp times and potential complications related to peripheral cannulation. Appropriate patient selection is very important. Since the procedure is more complex than conventional AVR, more intensive teamwork in the operating room is essential. Additionally, a team approach during postoperative management is critical to maximize the benefits of MIAVR. PMID:27295772

  11. Quantitative assessment of an aortic and pulmonary valve function according to valve fenestration

    International Nuclear Information System (INIS)

    There are some reasons for malfunction of aortic and pulmonary valve like fibrosis, calcification, and atheroma. Although, in some papers fenestration were known as a pathologic sign, but it is not generally accepted, while this matter is important in choosing suitable Homograft Heart Valve. In this paper fenestrations and its size, numbers and situation effect was studied. We collected 98 hearts, the donors died because of accident, we excluded valves with atheroma, calcification, fibrosis and unequal cusps, 91 aortic and 93 pulmonary valves were given further consideration. We classified valves according to situation, number and size of fenestration. Each valve was tested with 104 cm of non-nal saline column pressure which is equal to 76 mm Hg. Valve efficacy was detected by fluid flow assay. With study of 184 valves, 95 had no fenestration, 64 had less than 2 fenestration and 25 had more than 2 fenestration. Valve efficacy in condition of less than 2 fenestration was more than others (p <0.01). Malfunction effects of fenestration increased in larger valve and it will be decreased if their situation would be marginal (free margin of cusp). In the comparison of aortic and pulmonary valve we saw that malfunction effect of fenestration in pulmonary valve was more than aortic valve. Our experience in Immam Khomeini Homograft Valve Bank has shown that a great deal of valves is fenestrated. It seems that fenestration must be considered as a quality criterion in homograft valve preparation, especially in pulmonary and large aortic valves; but complementary studies is necessary

  12. Recently patented and widely used valves for transcatheter aortic valve implantation.

    Science.gov (United States)

    Neragi-Miandoab, Siyamek; Skripochnik, Edvard; Michler, Robert E

    2012-12-01

    Aortic stenosis (AS) is a serious condition in the aging US and European populations. Management of a stenotic valve is crucial as it can become symptomatic quickly leading to ventricular deterioration and overall poor quality of life. Considering that AS is a disease of the elderly patient population, surgical intervention may not be well tolerated by some patients. Transcatheter aortic valve implantation (TAVI) has emerged as an alternative approach for patients who are unsuitable surgical candidates. Since the first balloon-expandable Edwards SAPIEN valve (Edwards Lifesciences, Irvine, CA) was implanted by Dr. Cribier, many other valves have been introduced into clinical practice. Self-expanding valves such as the CoreValve ReValving system (Medtronic, Minneapolis, MN) for retrograde implantation and Symetis TX for antegrade and transapical implantation are the most frequently used self-expanding valves. The SAPIEN valve, on the other hand can be implanted both antegrade as well as retrograde. Overall, the most widely used valves are the Edwards SAPIEN and the CoreValve, which have been implanted in more than 40,000 patients worldwide. The Symetis valve has shown promising results in small series in Europe and may be introduced to the US market in the near future. This manuscript will review these 3 recently patented valves and discuss some of the clinical results that are available. PMID:23095028

  13. Control valve friction operational experience at Darlington NGD

    International Nuclear Information System (INIS)

    Proper installation of valve packing is an important part of ensuring that control valves operate as intended. Darlington NGD has developed a Valve Packing Program. This program combined with valve diagnostics has enabled the station to ensure that the operability of control valves is maintained after repacking. This paper outlines the process that is used for this. (author)

  14. Valves for TPP and NPP in United Kingdom

    International Nuclear Information System (INIS)

    Standard requirements to TPP and NPP valves in the VK are shortly described. Value produser's guarantee, requirements to weld buttering of valve sealing surfaces and to valve quality are described. Devices for valve setting and sealing surfaces grinding, valve control operation, preparation and placing of sealings are described too. Set-ups for hydraulic testing are described

  15. Quality control checks and balances in ENSDF

    International Nuclear Information System (INIS)

    The Evaluated Nuclear Structure Data File (ENSDF) is the repository of data evaluated by the members of the International Nuclear Structure and Decay Data Network. This network includes evaluators at 15 data centers in 10 countries and operates under the auspices of the International Atomic Energy Agency. The main output of the data from this file is the journal Nuclear Data Sheets, widely used by the nuclear structure research community; however, specialized output from this file is also prepared for applied users in the fields of medical practice and research, health physics, industry, nuclear power, and environmental protection. This paper describes the various means each evaluator has access to including format-checking programs and programs for checking/evaluating physical quantities and calculations

  16. Advanced techniques for efficient data integrity checking

    DEFF Research Database (Denmark)

    Martinenghi, Davide

    Integrity constraint checking, understood as the verification of data correctness and well-formedness conditions that must be satisfied in any state of a database, is not fully supported by current database technology. In a typical scenario, a database is required to comply with given semantic cr...... contexts, such as recursive databases, concurrent database systems, data integration systems and XML document collections, and provide a performance evaluation of the proposed model.......Integrity constraint checking, understood as the verification of data correctness and well-formedness conditions that must be satisfied in any state of a database, is not fully supported by current database technology. In a typical scenario, a database is required to comply with given semantic...... criteria (the integrity constraints) and to maintain the compliance each time data are updated. Since the introduction of the SQL2 standard, the SQL language started supporting assertions, which allow one to define general data consistency requirements expressing arbitrarily complex “business rules” that...

  17. Postcode Lotteries in Public Health - The NHS Health Checks Programme in North West London

    Directory of Open Access Journals (Sweden)

    McCoy David C

    2011-09-01

    Full Text Available Abstract Background Postcode lotteries in health refer to differences in health care between different geographic areas. These have been previously associated with clinical services. However there has been little documentation of postcode lotteries relating to preventative health care services. This paper describes a postcode lottery effect in relation to the NHS Health Checks Programme (a national cardiovascular screening programme in England in eight PCTs in the North West sector of London. Methods A descriptive cross-sectional analysis of the Health Checks Programme was carried out in eight PCTs in North West London using a structured data-collecting instrument. Results The analysis found variation in the implementation of the national Health Checks Programme in terms of: the screening approach taken; the allocated budget (which varied from £69,000 to £1.4 million per 100,000 eligible population; payment rates made to providers of Health Checks; tools used to identify and measure risk of cardiovascular disease and diabetes; monitoring and evaluation; and preventative services available following the health check. Conclusions This study identifies a postcode lottery effect related to a national public health programme. Although it is important to allow enough flexibility in the design of the Health Checks Programme so that it fits in with local factors, aspects of the programme may benefit from greater standardisation or stronger national guidance.

  18. Force measuring valve assemblies, systems including such valve assemblies and related methods

    Science.gov (United States)

    DeWall, Kevin George; Garcia, Humberto Enrique; McKellar, Michael George

    2012-04-17

    Methods of evaluating a fluid condition may include stroking a valve member and measuring a force acting on the valve member during the stroke. Methods of evaluating a fluid condition may include measuring a force acting on a valve member in the presence of fluid flow over a period of time and evaluating at least one of the frequency of changes in the measured force over the period of time and the magnitude of the changes in the measured force over the period of time to identify the presence of an anomaly in a fluid flow and, optionally, its estimated location. Methods of evaluating a valve condition may include directing a fluid flow through a valve while stroking a valve member, measuring a force acting on the valve member during the stroke, and comparing the measured force to a reference force. Valve assemblies and related systems are also disclosed.

  19. The radiology of prosthetic heart valves

    International Nuclear Information System (INIS)

    The development of prosthetic heart valves in the late 1950s ushered in a new era in the treatment of heart disease. The radiologist has an important role to play preoperatively in the diagnosis of valvular heart disease. Radiology is valuable in identification of the implanted prosthetic valve and recognition of complications associated with valve implantation. Radiologists must be familiar with the imaging techniques best suited to evaluate the function of the valve prosthesis in question. In this chapter the authors discuss the radiographic approach to the evaluation of the status of patients for valve replacement and the imaging problems peculiar to the types of valves in current use. The relative value of plain-film radiography, fluoroscopy, videorecording and cinerecording, and aortography is addressed, as well as the potential value of magnetic resonance imaging and subsecond dynamic computed tomography

  20. Stop and regulating valves for radiochemical plants

    International Nuclear Information System (INIS)

    The papers on developing stop and regulating valves and selecting material for these valves are reviewed. The main technical requirements of the radiochemical production to the valves are: the fluid stream velocity of 0.2-10000 l/s, remote exchange, one year lifetime or 15O00 cycles, the pressure and temperature of the fluid up to 0.6 MPa and up to 120 deg C. It is presupposed to use 03Cr18Ni12 and 03Cr18Ni12MO2-3 type steels for these valves. The CrWCO type lining materials for the working medium of nitrogen acid are acknowledged unfit. Significantly better anticorrosion properties are found for the electrodes with the 1Cr18Ni Mo2-5 Mn2-4 type lining. The bellow valve design meets the suggested technical requirements most fully. Two perspective projects of the valve of this type are presented

  1. 3D Printed Multimaterial Microfluidic Valve.

    Science.gov (United States)

    Keating, Steven J; Gariboldi, Maria Isabella; Patrick, William G; Sharma, Sunanda; Kong, David S; Oxman, Neri

    2016-01-01

    We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics. PMID:27525809

  2. 3D Printed Multimaterial Microfluidic Valve

    Science.gov (United States)

    Patrick, William G.; Sharma, Sunanda; Kong, David S.; Oxman, Neri

    2016-01-01

    We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics. PMID:27525809

  3. Speed checks on the CERN site

    CERN Multimedia

    2007-01-01

    In view of the significant number of speeding incidents that have been reported, CERN will shortly start to carry out speed checks on the site. The radar used for this purpose will show drivers the speed measured. The disciplinary measures taken against those exceeding the authorised limit (generally 50 k.p.h.) will include a ban from driving on the site for a minimum of one month. Maximilian Metzger
Secretary-General

  4. Checking C Pointer Programs for Memory Safety

    OpenAIRE

    Moy, Yannick

    2007-01-01

    We propose an original approach for checking memory safety of C pointer programs possibly including pointer arithmetic and sharing (but no casts, structures, double indirection or memory deallocation). This involves first identifying aliasing and strings, which we do in a local setting rather than through a global analysis as it is done usually. Our separation analysis in particular is a totally new treatment of non-aliasing. We present for the first time two abstract lattices to deal with lo...

  5. Statistical Model Checking for Stochastic Hybrid Systems

    DEFF Research Database (Denmark)

    David, Alexandre; Du, Dehui; Larsen, Kim Guldstrand; Legay, Axel; Mikučionis, Marius; Poulsen, Danny Bøgsted; Sedwards, Sean

    This paper presents novel extensions and applications of the UPPAAL-SMC model checker. The extensions allow for statistical model checking of stochastic hybrid systems. We show how our race-based stochastic semantics extends to networks of hybrid systems, and indicate the integration technique...... applied for implementing this semantics in the UPPAAL-SMC simulation engine. We report on two applications of the resulting tool-set coming from systems biology and energy aware buildings....

  6. From model checking to model measuring

    OpenAIRE

    Henzinger, Thomas A.; Otop, Jan

    2013-01-01

    We define the model-measuring problem: given a model $M$ and specification~$\\varphi$, what is the maximal distance $\\rho$ such that all models $M'$ within distance $\\rho$ from $M$ satisfy (or violate)~$\\varphi$. The model measuring problem presupposes a distance function on models. We concentrate on automatic distance functions, which are defined by weighted automata. The model-measuring problem subsumes several generalizations of the classical model-checking problem, in particular, qu...

  7. The Activity Check of Brachytherapy Isotope

    International Nuclear Information System (INIS)

    An isotope Ir-192, which is used in brachytherapy depends on import in whole quantities. There are a few ways for its activity. measurement using Welltype chamber or the way to rely on authentic decay table of manufacturer. In-air dosimetry using Farmer Chamber, etc. In this paper, let me introduce the way using Farmer chamber which is easier and simple. With the Farmer chamber and source calibration jig, take a measurement the activity of an isotope Ir-192 and compare the value with the value from decay table of manufacturer and check the activity of source. The result of measurement, compared the value from decay table, by ±2.1. (which belongs to recommendable value for AAPM ±5% as difference of error range). It is possible to use on clinical medicine. With the increase in use of brachytherapy, the increase of import is essential. And an accurate activity check of source is compulsory. For the activity check of source, it was possible to use Farmer chamber and source calibration jig without additional purchase of Well type chamber.

  8. Insulin Micropump with Embedded Pressure Sensors for Failure Detection and Delivery of Accurate Monitoring

    Directory of Open Access Journals (Sweden)

    Dimitry Dumont-Fillon

    2014-11-01

    Full Text Available Improved glycemic control with insulin pump therapy in patients with type 1 diabetes mellitus has shown gradual reductions in nephropathy and retinopathy. More recently, the emerging concept of the artificial pancreas, comprising an insulin pump coupled to a continuous glucose meter and a control algorithm, would become the next major breakthrough in diabetes care. The patient safety and the efficiency of the therapy are directly derived from the delivery accuracy of rapid-acting insulin. For this purpose, a specific precision-oriented design of micropump has been built. The device, made of a stack of three silicon wafers, comprises two check valves and a pumping membrane that is actuated against stop limiters by a piezo actuator. Two membranes comprising piezoresistive strain gauges have been implemented to measure the pressure in the pumping chamber and at the outlet of the pump. Their high sensitivity makes possible the monitoring of the pumping accuracy with a tolerance of ±5% for each individual stroke of 200 nL. The capability of these sensors to monitor priming, reservoir overpressure, reservoir emptying, outlet occlusion and valve leakage has also been studied.

  9. Variable-Aperture Reciprocating Reed Valve

    Science.gov (United States)

    Lindner, Jeffrey L. (Inventor); Myers, W. Neill (Inventor); Kelley, Anthony R. (Inventor); Yang, Hong Q. (Inventor)

    2015-01-01

    A variable-aperture reciprocating reed valve includes a valve body defining a through hole region having a contoured-profile portion. A semi-rigid plate is affixed on one side thereof to the valve body to define a cantilever extending across the through hole region. At least one free edge of the cantilever opposes the contoured-profile portion of the through hole region in a non-contact relationship.

  10. Flow and plate motion in compressor valves

    OpenAIRE

    Habing, Reinder André

    2005-01-01

    The Basic Valve Theory is based on steady ow characteristics. Therefore unsteady ow conditions in the model valve have been considered in order to assess effects of unsteadiness on the performance of the Basic Valve Theory. The instantaneous gas force was predicted rather accurately by the theory. However, it has also been observed that ow hystersis effects are present. These effects are postulated to be caused by a periodically detaching and reattaching ow at the seat. This hypothesis has be...

  11. Valves for TPP and NPP in France

    International Nuclear Information System (INIS)

    Valves produced by the leading French firms for TPP and NPP are described in brief on the base of prospects presented at the ''Oil and Gas-83'' exhibition in Moscow. The method of testing for leak-tightness applied in the production of the valves is considered as wetl as the main parameters of working fluids for which some types of the valves are intended

  12. MARFAN SYNDROME AND QUADRICUSPID AORTIC VALVE

    OpenAIRE

    Sürücü, Hüseyin; ÇİMEN, Sadi

    2013-01-01

    ABSTRACTWhile the major cardiovascular manifestation in Marfan syndrome is a progressive dilatation of the ascending aorta, leading to aortic aneurysm formation and eventually to fatal aortic rupture or dissection, mitral valve prolapse and calcification of the mitral valve annulus, dilatation of the main pulmonary artery may be seen. There was no knowledge about the association of Marfan syndrome and quadricuspid aortic valve. In this case report, we aimed to declare this association between...

  13. Evolving Indications for Tricuspid Valve Surgery

    OpenAIRE

    McCarthy, Patrick M; Sales, Virna L.

    2010-01-01

    Opinion statement More attention has been paid to the mitral valve (MV) than the tricuspid valve (TV), and this relative paucity of data has led to confusion regarding the timing of TV surgery. We review the American College of Cardiology/American Heart Association and European Society of Cardiology guidelines to identify areas of concordance (severe tricuspid regurgitation [TR] in a patient undergoing mitral valve surgery); discordance (less than severe TR but with markers for late TR recurr...

  14. Fluidic valve for reactor regeneration flow switching

    OpenAIRE

    Tesar, V

    2004-01-01

    An unusual and in many respects advantageous no-moving-part valve is described,developed for switching fluid flows in a through-flow reactor that requires a periodic regeneration by temporary replacement of the process fluid by another, regeneration fluid. The unusual feature of the valve is that it is axisymmetric, built integrally into the inlet part of the reactor body. The valve operation is based upon a monostable axisymmetric variant of the Coanda effect of jet attachment to a wall. ...

  15. Voice Coil Controlled Inspiration and Expiration Valves

    OpenAIRE

    Bergqvist, Per; Kemmler, Linus

    2012-01-01

    This master thesis was performed at Maquet Critical Care located in Solna, Stockholm. Maquet Critical Care is a market leader in high performance medical ventilators. A ventilator is a medical device that helps patients to breathe. Two of the most vital components of a ventilator are the valves that are closest to the patient. These are the inspiration valve and the expiration valve. The main purpose with this thesis is to get, theoretical as well as practical insights into the inspiration an...

  16. Aortic valve replacement through right thoracotomy.

    OpenAIRE

    Rao, P N; A S Kumar

    1993-01-01

    There has never, to our knowledge, been a report of aortic valve replacement via a right thoracotomy. However, we recently used this approach in 2 young women with severe aortic stenosis. Exposure of the aortic valve was excellent, and we encountered neither technical difficulties nor sequelae related to the right thoracotomy. We believe that right thoracotomy provides adequate access for safe aortic valve replacement and yields cosmetically more appealing results than does median sternotomy.

  17. The Melody® valve and Ensemble® delivery system for transcatheter pulmonary valve replacement

    OpenAIRE

    McElhinney, Doff B.; Hennesen, Jill T

    2013-01-01

    The Melody® transcatheter pulmonary valve (TPV) is a percutaneous valve system designed for the treatment of obstruction and/or regurgitation of prosthetic conduits placed between the right ventricle and pulmonary arteries in patients with congenital heart disease. In 2000, Melody TPV became the first transcatheter valve implanted in a human; in 2006 it became the first transcatheter valve commercially available anywhere in the world; and in 2010 it was launched as the first commercially avai...

  18. Human Mesenchymal Stem Cells Reendothelialize Porcine Heart Valve Scaffolds: Novel Perspectives in Heart Valve Tissue Engineering

    OpenAIRE

    Lanuti, Paola; Serafini, Francesco; Pierdomenico, Laura; Simeone, Pasquale; Bologna, Giuseppina; Ercolino, Eva; Di Silvestre, Sara; Guarnieri, Simone; Canosa, Carlo; Impicciatore, Gianna Gabriella; Chiarini, Stella; Magnacca, Francesco; Mariggiò, Maria Addolorata; Pandolfi, Assunta; Marchisio, Marco

    2015-01-01

    Abstract Heart valve diseases are usually treated by surgical intervention addressed for the replacement of the damaged valve with a biosynthetic or mechanical prosthesis. Although this approach guarantees a good quality of life for patients, it is not free from drawbacks (structural deterioration, nonstructural dysfunction, and reintervention). To overcome these limitations, the heart valve tissue engineering (HVTE) is developing new strategies to synthesize novel types of valve substitutes,...

  19. Pump intake pressure determined from fluid levels, dynamometers, and valve test measurements

    Energy Technology Data Exchange (ETDEWEB)

    Rowlan, O.L.; McCoy, J.N. [Echometer Company, Wichita Falls, TX (United States); Podio, A.L. [Texas Univ., Austin, TX (United States)

    2009-07-01

    Downhole pump submergence is defined as the amount or height of liquid that exists above the pump intake. Pump submergence is the parameter most used for monitoring and troubleshooting well operations. In the 1930s, acoustic determination of the depth to the liquid in the wellbore was introduced. The advent of digital data acquisition and processing provided the tools to regularly convert fluid level measurements to estimates of downhole pressure distribution in the wellbore. Pump submergence is now easily converted to pressure at the depth of the pump intake. This paper presented a detailed discussion of three pump intake pressure (PIP) calculation methods available for sucker rod lifted wells. Field data for a significant group of wells were then utilized to compare the PIP results of the three methods. The paper provided background information on PIP from acoustic fluid levels and discussed the PIP calculation method using acoustic fluid level survey. The requirements for accuracy of the computer pressures were also discussed, with particular reference to stabilization; percentage of liquid in annular gaseous column; fluid level depth; and height of the gaseous liquid column. The paper also provided guidelines to obtain a best estimate of PIP from fluid level measurements. The PIP calculation method using valve check measurements, PIP from dynamometer pump card, and PIP calculation method using pump dynamometer values were presented. The requirements for accuracy for the dynamometer pump included damping coefficient; pump card shifted off zero load line; hydraulic friction; and tubing head pressure variation. Last, a comparison of methods for typical rod pump wells was provided. It was concluded that as a general rule, the user should not accept default computation of PIP by any of the three methods. The user must review the results based on knowledge and experience and verify that the computed values are realistic. 13 refs., 4 tabs., 9 figs.

  20. Use of statistical checks as maintenance tools for TLD readers

    International Nuclear Information System (INIS)

    Although the values of different parameters may remain within permissible limits during the operation of a thermoluminescent dosemeter (TLD) reader, certain effects can become apparent only when a long-term followup of these parameters is performed. In order to ensure an accurate and reliable operation of a TLD reader, the system characteristics must be monitored continuously. Long-term statistical checks of key system parameters may give a broader insight into the operational characteristics of the TLD reader and may help for proper maintenance of the system. The photomultipliers noise, the internal reference light source stability and the A to D reference voltage were found to be critical parameters, which have a major influence on the accuracy and stability of the system. A followup of these parameters for a period of about 10 y is presented, and some problems are seen to be reflected in the distributions. (authors)