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Sample records for check valve monitoring

  1. 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.

  2. 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

  3. 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)

  4. 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

  5. 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.

  6. 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...

  7. Microbial Check Valve for Shuttle

    Science.gov (United States)

    Colombo, G. V.; Putnam, D. F.; Sauer, R. L.

    1978-01-01

    The Microbial Check Valve (MCV) is a device developed for the Space Shuttle that prevents the transfer of viable microorganisms within water systems. The device is essentially a bed of resin material, impregnated with iodine, that kills microorganisms on contact. It prevents the cross-contamination of microorganisms from a nonpotable system into the potable water system when these systems are interconnected. In this regard, the function of the device is similar to that of the 'air gap' found in conventional one-gravity systems. Basic design data are presented including pressure drop, scaling factors, sizing criteria, and the results of challenging the device with suspensions of seven microorganisms including aerobes, anaerobes and spore formers.

  8. Floating-disk parylene micro check valve

    OpenAIRE

    Chen, Po-Jui; Tai, Yu-Chong

    2008-01-01

    A novel micro check valve which has nearly ideal fluidic shunting behaviors is presented. Featuring a parylene-based floating disk, this surface-micromachined check valve ultimately realizes both zero forward cracking pressure and zero reverse leakage in fluidic operations. Two different floating disk designs have been implemented to demonstrate functionality of the microvalve. Experimental data of underwater testing successfully show that in-channel floating-disk valv...

  9. 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

  10. Advanced microbial check valve development

    Science.gov (United States)

    Colombo, G. V.; Greenley, D. R.

    1980-01-01

    A flight certified assembly identified as a Microbial Check Valve (MCV) was developed and tested. The MCV is a canister packed with an iodinated anionic exchange resin. The device is used to destroy organisms in a water stream as the water passes through the device. The device is equally effective for fluid flow in either direction and its primary method of organism removal is killing rather than filtering. The MCV was successfully developed for the space shuttle to: disinfect fuel cell water; and prevent back contamination of the stored potable water supply. One version of the device consists of a high residual iodinated resin bed that imparts approximately 2 ppm of iodine to the fuel cell water as it flows to the potable water tanks. A second version of the device consists of a low residual iodinated resin bed. One of these low residual beds is located at each use port in the potable water system for the dual purpose of removing some iodine from the potable water as it is dispensed and also to prevent back contamination of the potable supply.

  11. Improved microbial-check-valve resins

    Science.gov (United States)

    Colombo, G. V.; Putnam, D. F.

    1980-01-01

    Improved microbial-check-valve resins have been tested for their microbicidal effectiveness and long-term stability. Resins give more-stable iodine concentrations than previous preparations and do not impart objectionable odor or taste to treated water. Microbial check valve is small cylindrical device, packed with iodide-saturated resin, that is installed in water line where contamination by micro-organisms is to be prevented. Prototype microbial check valve was tested for stability and performance under harsh environmental conditions. Effectiveness was 100 percent at 35 deg, 70 deg, and 160 deg F (2 deg, 21 deg, and 71 deg C).

  12. 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.

  13. 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.

  14. 42 CFR 84.137 - Inhalation and exhalation valves; check valves; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Inhalation and exhalation valves; check valves... PROTECTIVE DEVICES Supplied-Air Respirators § 84.137 Inhalation and exhalation valves; check valves; minimum requirements. (a) Inhalation and exhalation valves shall be provided where necessary and protected...

  15. Development of a stainless steel check valve for cryogenic applications

    NARCIS (Netherlands)

    Veenstra, T.T.; Venhorst, G.C.F.; Burger, J.F.; Holland, H.J.; Brake, ter H.J.M.; Sirbi, A.; Rogalla, H.

    2007-01-01

    This paper describes the development of a check valve for use in a sorption compressor that will drive a 10 mW 4.5 K Joule–Thomson cryocooler. For the check valve extremely low backflow rates are tolerable at an operating temperature of the valve of 50 K. To fulfill these requirements, the sealing m

  16. Water system microbial check valve development

    Science.gov (United States)

    Colombo, G. V.; Greenley, D. R.; Putnam, D. F.

    1978-01-01

    Development work on a device for the Space Shuttle that will prevent the transfer of viable microorganisms within water systems is described. The device serves as a check valve in that it prevents the transfer or cross-contamination of microorganisms from a nonpotable system into a potable water system when these systems are interconnected. In this regard, the function of the device is similar to that of the air gap found in conventional one gravity systems. The device is essentially a bed of resin material impregnated with iodine. Basic design data for a variety of flow and temperature conditions are presented, together with results of challenging the beds with suspensions of seven microorganisms including aerobes, anaerobes, and spore formers.

  17. 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.

  18. 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

  19. Experimental and Analytical Study on the Lift Check Valve

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. H.; Song, C. S.; Kim, H. S.; Hong, S. C. [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of); Lee, W. H. [Samshin Limited Co., Chonan (Korea, Republic of)

    2009-10-15

    In general, the check valve mounted on the flow line is used for the purpose of protecting the pump and the related facility, making the flow path, and maintaining the pressure boundary during the operation mode change in steam power plant and nuclear power plant. Fig. 1 shows the example of check valve in nuclear power plant. Especially, the check valve mounted on safety feed system and nuclear safety system is operated to open state and has a role of acquiring enough fluid such as safety feed and auxiliary feed water in the Design Basis Accident. And the check valve is operated with enough sealing and with protecting steam hammer in normal operational mode. For this purpose, the check valve can be open easily and be maintained in the open state in case of small flow velocity. In this research, the experimental and analytical study on the check vale was performed. The flow coefficient and closure time were compared between the experimental and the analytical result by numerical simulation. The validation of the analytical method was performed.

  20. Development of a stainless steel check valve for cryogenic applications

    Science.gov (United States)

    Veenstra, T. T.; Venhorst, G. C. F.; Burger, J. F.; Holland, H. J.; ter Brake, H. J. M.; Sirbi, A.; Rogalla, H.

    2007-02-01

    This paper describes the development of a check valve for use in a sorption compressor that will drive a 10 mW 4.5 K Joule-Thomson cryocooler. For the check valve extremely low backflow rates are tolerable at an operating temperature of the valve of 50 K. To fulfill these requirements, the sealing mechanism of the valve is based on a full metal to metal contact. In order to obtain sufficiently low leak rates, both parts were machined to a surface flatness in the order of 100 nm. In addition, the closing plate (boss) of the valve deforms (bends) slightly under pressure, forming itself to the opposite valve seat and thus reducing the gap between these parts. The measured leak flow at 50 K was 1.6 μg/s helium @ 16 bar pressure difference, which is well below the aim of 3 μg/s. The valve was subjected to an accelerated lifetime test of 300,000 cycles. It was observed that the leak flow through the valve during this test steadily decreased to a level of 0.15 μg/s after 100,000 cycles.

  1. Miniaturized passive hydrogel check valve for hydrocephalus treatment.

    Science.gov (United States)

    Schwerdt, Helen N; Bristol, Ruth E; Junseok Chae

    2014-03-01

    Improvements in cerebrospinal fluid (CSF) draining techniques for treatment of hydrocephalus are urgently sought after to substitute for current CSF shunts that are plagued by high failure rates. The passive check valve aims to restore near natural CSF draining operations while mitigating possible failure mechanisms caused by finite leakage or low resilience that frequently constrain practical implementation of miniaturized valves. A simple hydrogel diaphragm structures core passive valve operations and enforce valve sealing properties to substantially lower reverse flow leakage. Experimental measurements demonstrate realization of targeted cracking pressures (PT ≈ 20-110 mmH2O) and operation at -800 <; ΔP <; 600 mmH2O without observable degradation or leakage.

  2. 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

  3. 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.

  4. 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...

  5. 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.

  6. 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

  7. 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.

  8. 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%.

  9. 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

    /Off and bidirectional check valves. Based on the analysis it is found that the energy production may be slightly improved by using bidirectional check valves as compared to on/off valves, due to a decrease in switching losses. Furthermore a reduction in high flow peaks are realised. The downside being increased...... 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 multiple common pressure lines. The valve manifold, employed in the discrete PTO system and conventionally equipped with On/Off valves, is instead considered fitted with bidirectional check valves. The energy output from the primary stage is compared for PTO systems occupying respectively On...

  10. Design of Bidirectional Check Valve for Discrete Fluid Power Force System for Wave Energy Converters

    DEFF Research Database (Denmark)

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

    2014-01-01

    Discrete fluid power force systems consisting of a multichamber cylinder, a witching manifold and common pressure lines have been proposed as a technology for increasing the efficiency of the power take off system in ocean wave energy converters. However the force shifting of these discrete systems...... introduces large switching losses, especially when large pressure difference is present across the valves in the manifold. The current paper therefore focus on designing a bidirectional check valve for use in the switching manifold of the discrete force systems. The use of the bidirectional check valve...... enables passive force switching under minimal pressure difference, hence minimal energy loss. The bidirectional check valve is designed with a rated flow in the range of 1000L/min@5bar. The flow direction of the bidirectional check valve is set by the setting the pilot pressure. This paper presents...

  11. 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

  12. Valve-"Health"-Monitoring System

    Science.gov (United States)

    Jensen, Scott L.; Drouant, George J.

    2009-01-01

    A system that includes sensors and data acquisition, wireless data-communication, and data-processing subsystems has been developed as a means of both real-time and historical tracking of information indicative of deterioration in the mechanical integrity and performance of a highgeared ball valve or a linearly actuated valve that operates at a temperature between cryogenic and ambient.

  13. Pump, and earth-testable spacecraft capillary heat transport loop using augmentation pump and check valves

    Science.gov (United States)

    Baker, David (Inventor)

    1998-01-01

    A spacecraft includes heat-generating payload equipment, and a heat transport system with a cold plate thermally coupled to the equipment and a capillary-wick evaporator, for evaporating coolant liquid to cool the equipment. The coolant vapor is coupled to a condenser and in a loop back to the evaporator. A heated coolant reservoir is coupled to the loop for pressure control. If the wick is not wetted, heat transfer will not begin or continue. A pair of check valves are coupled in the loop, and the heater is cycled for augmentation pumping of coolant to and from the reservoir. This augmentation pumping, in conjunction with the check valves, wets the wick. The wick liquid storage capacity allows the augmentation pump to provide continuous pulsed liquid flow to assure continuous vapor transport and a continuously operating heat transport system. The check valves are of the ball type to assure maximum reliability. However, any type of check valve can be used, including designs which are preloaded in the closed position. The check valve may use any ball or poppet material which resists corrosion. For optimum performance during testing on Earth, the ball or poppet would have neutral buoyancy or be configured in a closed position when the heat transport system is not operating. The ball may be porous to allow passage of coolant vapor.

  14. Development and testing of a passive check valve for cryogenic applications

    Science.gov (United States)

    Moore, B. D.; Maddocks, J. R.; Miller, F. K.

    2014-11-01

    Several cryogenic technologies use check valves, such as the Cold Cycle Dilution Refrigerator (CCDR) and the Hybrid Pulse-Tube/Reverse-Brayton Cryocooler. This paper details the development of a reed-style passive check valve with a PTFE seat for cryogenic applications. The experimental results of tests on the valve using helium gas at temperatures from 293 K down to 5.2 K, verify a scaling argument based on fundamental fluid dynamics that allows results from 78 K to be used in predicting valve performance at much lower temperatures. The scaling argument is then applied to a test conducted at the normal boiling point of Nitrogen to examine the results of improved fabrication methods.

  15. 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)

  16. 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.

  17. 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

  18. 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 ...

  19. Modeling of feed water check valves using RELAP5; Modellierung von Speisewasserrueckschlagventilen in RELAP5

    Energy Technology Data Exchange (ETDEWEB)

    Ben Said, Nader; Bregulla, Wolfgang; Kalk, Andreas [Westinghouse Electric Germany GmbH, Mannheim (Germany)

    2009-07-01

    Westinghouse Electric Germany GmbH has developed fluid dynamic models for medium-actuated armatures using the thermal hydraulic code RELAP5 in order to reach a more realistic description of the armature behavior including fluid-structure interactions in case of transient flow conditions in piping systems. The contribution is concerned with the modeling of damped check valves. The model allows the description of the behavior during opening and closure of a check armature. The calculated results show good agreement with the available measured data.

  20. 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

  1. 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.

  2. 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

  3. 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)

  4. 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.

  5. 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.

  6. The seat test of axial flow check valves%轴流式止回阀的密封试验

    Institute of Scientific and Technical Information of China (English)

    彭林; 宋忠荣; 刘建峰; 张绍华; 陶国庆

    2012-01-01

    Analyses the structure and properties of axial flow check valves, and introduces the methods for seat test of axial flow check valves, the design and construction scheme of test system, and verifies the properties of the test system with the simulation conditions.%分析了轴流式止回阀的结构与性能特点,介绍了轴流式止回阀的密封试验方法、试验系统的设计与建设,并结合输送流体工况对试验系统的效果进行了验证。

  7. 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.

  8. Haemostasis monitoring during sequential aortic valve replacement and liver transplantation

    NARCIS (Netherlands)

    Sieders, E.; De Somer, F.; Bouchez, S.; Szegedi, L.; Van Belleghem, Y.; Colle, I.; Troisi, R.

    2010-01-01

    Despite advances in anaesthesiological and surgical techniques, cardiac surgery in cirrhotic patients remains hazardous. This report outlines our experience with haemostasis monitoring in two consecutive cases of sequential aortic valve replacement and liver transplantation. Clotting disturbances pr

  9. 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)

  10. 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)

  11. 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.

  12. 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.

  13. Waste Heat Recovery by Closed-Loop Oscillating Heat Pipe with Check Valve from Pottery Kilns for Energy Thrift

    Directory of Open Access Journals (Sweden)

    P. Meena

    2008-01-01

    Full Text Available This study aims to design, construct and test the waste heat recovery by closed-loop oscillating heat pipe with check valve from pottery kilns for energy thrift, were used the working fluids with a filling ratio of 50%. The (CLOHO/CV was made of copper capillary tube with inside diameter of 2.03 mm. The lengths of evaporator and condenser section were 20 cm. The lengths of adiabatic section 10 cm. The number of turn was 40 meandering turns. The ratio of number of check valves was 0.04. The evaporator section was heated by hot gas, while the condenser section was cooled by fresh air. From the experiment, it indicated that the working fluid changes form water to R123, the heat transfer rate increased to 4,800 and 7,900 Watts and the effectiveness increased from 0.32 to 0.44. The CLOHP/CV heat exchanger can reduce the quantity of using gas in pottery kilns and achieve energy thrift.

  14. Water hammer analysis. Dynamic simulation model check valve piston; Analisis del golpe de airete. Modelo de simulacion dinamica de valvula de retencion piston

    Energy Technology Data Exchange (ETDEWEB)

    Royo, B.; Valdes, R.

    2012-11-01

    This report contains the description and the results of the dynamic simulation model that has been developed to predict the behaviour of one of our lift check valve design. The aim of the model is not only to simulate the closing process of the valve and to product the magnitude of the water hammer effect that may appear immediately after the valve closing, but also to simulate several design version until obtain the optimum which further minimizes such effect. the input data used for this study ensure reliable results since they represent a real system. (Author)

  15. 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。

  16. 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.

  17. 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...

  18. 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…

  19. Comparisons of Heat Transfer Performance of a Closed-looped Oscillating Heat Pipe and Closed-looped Oscillating Heat Pipe with Check Valves Heat Exchangers

    Directory of Open Access Journals (Sweden)

    P. Meena

    2008-01-01

    Full Text Available This research was to study the comparisons of heat transfer performance of closed-looped oscillating heat pipe and closed-looped oscillating heat pipe with check valves heat exchangers with R134a, Ethanol and water were used as the working fluids. A set of heat pipe heat exchanger (CLOHP and CLOHP/CV were made of copper tubes in combination of following dimension: 2.03 mm inside diameter: 40 turns, with 20, 10 and 20 cm for evaporator, adiabatic and condenser sections lengths. 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 air. The adiabatic section was properly insulated. In the test operation, it could be concluded as follows. It indicated that the heat transfer performance of closed-looped oscillating heat pipe with check valves heat exchanger better than closed-looped oscillating heat exchanger.

  20. 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)

  1. 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)

  2. 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...

  3. Checking the Safety Valve with a Pressure Gauge Error Analysis and Reasonable Selection%安全阀校验用压力表误差分析与合理选用

    Institute of Scientific and Technical Information of China (English)

    常卫东

    2015-01-01

    Safety valve is a pressure relief device, plays an important role in security of pressure equipment, check after passing to the installation and use, the safety valve in the cold off-line checking with pressure gauge, precision, error range and the influence factors are deep discussed, grasp the technical aspects, has important significance on accuracy of safety valve calibration data.%安全阀是一种超压泄放装置,对承压设备起着重要的安全保障作用,校验合格后才能安装使用,对安全阀冷态离线校验用压力表精度、误差、量程及影响因素等方面进行深层次论述,抓好技术环节,对安全阀校验数据的准确性具有重要意义.

  4. Numerical Simulation and Experimental Study on the Tilt Double Disc Check Valve%斜置双瓣止回阀内部流态的模拟与试验研究

    Institute of Scientific and Technical Information of China (English)

    杜卫; 洪顺军; 吴义勇; 李志鹏; 何敬行; 周永芳

    2016-01-01

    With improving the existing problems of small opening angle and small flow resistance coefficient of common check valves,a new type of tilt double disc check valve was designed.analyses of the internal flow characteristics of the check valve were conducted when the check valve was operating at the angel of 30°,50°,70°,80°or entirely opened.Calculating the flow resistance coefficient and flow coefficient.It was tested pressure loss characteristics and flow characteristics test,in addition,the flow resistance coefficients and discharge coefficient were compared between simulation results.The results was that the simula-tion results and experimental results are consistent,and when the opening angle of the check valve was larger,the pressure loss would be less,the flow resistance coefficient would be smaller and the discharge coefficient would be larger,the flow capacity would be better.Through the numerical simulation and experimental study on the tilt double disc check valve,the design of the new tilt double disc check valve has guidance to the energy conservation of the fluid system.%为了改进普通止回阀存在的开启角度小、流阻系数大等不足,设计一种新型斜置双瓣止回阀,对其在30°、50°、70°、80°及全开工况下的内部流动特性进行分析,计算出流阻系数及流量系数.对其进行压力损失特性试验及流量特性试验,计算出每个工况下的流阻系数及流量系数,将其与模拟数据进行对比分析.研究结果表明,斜置双瓣止回阀的模拟结果与试验结果比较接近,开启角度大,压力损失小,流阻系数小,流量系数大,通流能力好.通过对斜置双瓣止回阀进行数值模拟及试验研究,斜置双瓣止回阀的设计对流体系统节能具有指导意义.

  5. Rain Check Application: Mobile tool to monitor rainfall in remote parts of Haiti

    Science.gov (United States)

    Huang, X.; Baird, J.; Chiu, M. T.; Morelli, R.; de Lanerolle, T. R.; Gourley, J. R.

    2011-12-01

    Rainfall observations performed uniformly and continuously over a period of time are valuable inputs in developing climate models and predicting events such as floods and droughts. Rain-Check is a mobile application developed in Google App Inventor Platform, for android based smart phones, to allow field researchers to monitor various rain gauges distributed though out remote regions of Haiti and send daily readings via SMS messages for further analysis and long term trending. Rainfall rate and quantity interact with many other factors to influence erosion, vegetative cover, groundwater recharge, stream water chemistry and runoff into streams impacting agriculture and livestock. Rainfall observation from various sites is especially significant in Haiti with over 80% of the country is mountainous terrain. Data sets from global models and limited number of ground stations do not capture the fine-scale rainfall patterns necessary to describe local climate. Placement and reading of rain gauges are critical to accurate measurement of rainfall.

  6. Effect of Check Valve on Consequences of Coolant Pump Rotor Seizure Accident for EPR Reactor%止回阀对EPR反应堆主泵卡轴事故后果的影响

    Institute of Scientific and Technical Information of China (English)

    陈秋炀; 周拥辉

    2012-01-01

    分析计算欧洲先进压水堆(EPR)反应堆主泵卡轴事故,并对比在主泵出口安装止回阀和没有安装止回阀模型的卡轴事故安全分析.结果表明,在EPR主泵卡轴事故中,止回阀可增加模型堆芯进口流量约4%,有利于堆芯的冷却.止回阀可显著地提高堆芯最小偏离泡核沸腾比(DNBR),降低堆芯偏离泡核沸腾(DNB)份额,降低包壳温度约14℃.模型分析结果表明,在主泵卡轴事故工况下,主泵出口安装止回阀可更好地维持堆芯的完整性.%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 without 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.

  7. 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.

  8. Effect of Inner Diameter and Inclination Angles on Operation Limit of Closed-Loop Oscillating Heat-Pipes with Check Valves

    Directory of Open Access Journals (Sweden)

    P. Meena

    2008-01-01

    Full Text Available This research was to study the effect of inner diameter and inclination angles on operation limit of a closed loop oscillating heat pipes with check valves (CLOHP/CV. A set of CLOHP/CV was made of copper tubes in combination of following dimension: 1.77 and 2.03 mm inside diameter: 10 turn, with R123 was used as the working fluid. The working fluid was filled in the tube at the filling ratio of 50%. The inclination angles were 0, 20, 40, 60, 80 and 90° with 5 equal lengths for evaporator, adiabatic and condenser sections. 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, it could be concluded as follows. It indicated that when the inner diameter changed from 1.77-2.03 mm the critical temperature increased. And when increase the inclination angles from 0 until to 90° the critical temperature increased.

  9. 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.

  10. ConfocalCheck--a software tool for the automated monitoring of confocal microscope performance.

    Directory of Open Access Journals (Sweden)

    Keng Imm Hng

    Full Text Available Laser scanning confocal microscopy has become an invaluable tool in biomedical research but regular quality testing is vital to maintain the system's performance for diagnostic and research purposes. Although many methods have been devised over the years to characterise specific aspects of a confocal microscope like measuring the optical point spread function or the field illumination, only very few analysis tools are available. Our aim was to develop a comprehensive quality assurance framework ranging from image acquisition to automated analysis and documentation. We created standardised test data to assess the performance of the lasers, the objective lenses and other key components required for optimum confocal operation. The ConfocalCheck software presented here analyses the data fully automatically. It creates numerous visual outputs indicating potential issues requiring further investigation. By storing results in a web browser compatible file format the software greatly simplifies record keeping allowing the operator to quickly compare old and new data and to spot developing trends. We demonstrate that the systematic monitoring of confocal performance is essential in a core facility environment and how the quantitative measurements obtained can be used for the detailed characterisation of system components as well as for comparisons across multiple instruments.

  11. Ablation for atrial fibrillation during mitral valve surgery: 1-year results through continuous subcutaneous monitoring.

    Science.gov (United States)

    Bogachev-Prokophiev, Alexandr; Zheleznev, Sergey; Romanov, Alexander; Pokushalov, Evgeny; Pivkin, Alexey; Corbucci, Giorgio; Karaskov, Alexander

    2012-07-01

    Continuous monitoring of cardiac rhythm may play an important role in measuring the true symptomatic/asymptomatic atrial fibrillation (AF) burden and improve the management of anti-arrhythmic and anti-thrombotic therapies. Forty-seven patients with mitral valve disease and longstanding persistent AF (LSPAF) underwent a left atrial maze procedure with bipolar radiofrequency and valve surgery. The follow-up data recorded by an implanted loop recorder were analysed after 3, 6 and 12 months. On discharge, 40 (85.1%) patients were in stable sinus rhythm, as documented by in-office electrocardiography (ECG), 4 (8.5%) were in pacemaker rhythm and 3 (6.4%) were in AF. One (2.1%) patient died after 7 months. On 12-month follow-up examination, 30 (65.2%) patients had an AF burden 0.5%. Two (4.3%) patients with AF recurrences were completely asymptomatic. Among the symptomatic events stored by the patients, only 27.6% was confirmed as genuine AF recurrences according to the concomitant ECG recorded by the implanted loop recorder. A concomitant bipolar maze procedure during mitral valve surgery is effective in treating AF, as proved by detailed 1-year continuous monitoring. PMID:22514258

  12. 40 CFR 53.52 - Leak check test.

    Science.gov (United States)

    2010-07-01

    ..., NIST-traceable. (2) Flow rate measurement adaptor (40 CFR part 50, appendix L, figure L-30) or... valve of the adaptor to seal the flow system. Conduct the external leak check procedure as described in... MONITORING REFERENCE AND EQUIVALENT METHODS Procedures for Testing Physical (Design) and...

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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

  18. 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...... often exact and ex- perimentally tight. The technique is implemented in the new tool Casaal that we seamlessly connect to Uppaal-smc in a tool chain. We demon- strate the applicability of our technique and the efficiency of our imple- mentation through a number of case-studies....

  19. 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.

  20. 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。

  1. 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

  2. Lockup Analysis and Study on Pilot Controlled Check Valve%液控单向阀锁死的原因分析与研究

    Institute of Scientific and Technical Information of China (English)

    李云; 李荣; 高兴利

    2009-01-01

    本文分析了打包机的锁门机构回路中,双向液控单向阀被锁死的原因.当液控单向阀的开启比大于液压缸的速比时,才有可能打开液控单向阀.所以选用液控单向阀应考虑与系统的压力及被锁紧的最大负载之间是否匹配,以避免液控单向阀被锁死.%The paper introduces the reason that the pilot controlled check value is locked in locking mechanism loop of baler. Only just the unlock ratio of pilot controlled check value is greater than the velocity ratio of oil cylinder, it may open up pilot controlled check value. To avoid pilot controlled check value of being locked, you should think that if it matches systemic pressure and maximum load of being locked.

  3. 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

  4. Study on Capacity Check Method of Feed Water Heater Safety Valves in Nuclear Power Plants%核电厂高加安全阀的排放容量校核方法研究

    Institute of Scientific and Technical Information of China (English)

    石建中; 黄超; 王志明; 胡友情

    2013-01-01

    火电厂的高加安全阀通常按照HEI标准推荐的原则进行选型计算,但因核电厂的高加一般要接受来自汽水分离再热器( MSR)的大量高温疏水,而当其疏水调节阀在全开位置失效时将有大量高压蒸汽直接进入高加,使其有发生超压的风险。因此,核电机组的高加安全阀选型除了要遵循HEI标准外,还需针对某些特殊工况进行校核。在分析了给水加热器、疏水调节阀以及抽汽管道的特性方程的基础上,从能量平衡的观点建立了确定系统平衡工作点的计算方法,利用该方法可简易计算出各种特殊工况的平衡工作压力,从而进一步判断安全阀的容量是否满足安全排放要求。%The selection of the high pressure feed water heater′s safety valve usually follows the principle recommended by HEI standards in thermal power plant .However ,the nuclear power plant′s heaters gener-ally need to accept a lots of drain from a moisture separator reheater ( MSR).When the drain regulating valve was failure in fully open position ,a large number of high pressure steam will directly goes into the heater.It make high-pressure heater have a risk of overpressure .Therefore,the safety valve selection of the heaters for nuclear power plants not only need to follow the HEI standards ,but also need to check his capacity in certain special conditions .The paper established a calculation method to determine the static running point of the heaters based on characteristic equations of the feed water heater , drain regulating valve and steam extraction pipings ,and energy balance principle .The method can be used to calculate the equilibrium pressure of various special running conditions ,so further determine whether the capacity of the safety valve meets the requirements of safety and emissions .

  5. 轴流式止回阀流阻特性检测方法的探讨%Research on testing method of flow resistance characteristics of axial flow check valve

    Institute of Scientific and Technical Information of China (English)

    缪克在; 林美

    2012-01-01

    Testing principle of flow resistance performances, design of testing equipment, inspection and analysis of axial check valve are introduced, and testing points selection method based on flow rate for using the function of pressure drop and flow rate is discussed, while recommended flow rate ranges for the testing of those samples with different nominal size are put forward.%阐述了轴流式止回阀的流阻性能测试原理、检测装置设计及检验与分析,探讨了利用压差一流速函数关系,以流速为依据选取测试点,并提出了不同公称尺寸轴流式止回阀的推荐测试点选取方法。

  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. Sodium Gill Potential as a Tool to Monitor Valve Closure Behavior in Freshwater Clam Corbicula fluminea in Response to Copper

    Directory of Open Access Journals (Sweden)

    Wei-Yu Chen

    2008-09-01

    Full Text Available Valve closure behavior in freshwater clam Corbicula fluminea is a biologically sensitive endpoint. The purpose of this paper was to derive an electrophysiological response model of C. fluminea to assess copper (Cu-sodium (Na interactions in gill membrane, whereby valve closure behavior and Cu toxicity could be monitored. The proposed model was based on the integration of Cu bioavailability, Na and Cu internalizations, and electrochemically-based gill potentials. Based on Na active transport under non-equilibrium conditions, predicted gill potential of -8.2 mV agreed reasonably well with published the measured transepithelial potential of -7 mV in C. fluminea. Our proposed framework captured the general features observed in model applications including: (i 50% inhibitory Cu2+ activities for Na membrane potential (ENa and uptake rate (JNa were estimated to be 0.072 and 0.043 mM, respectively, with a stoichiometry of 3Cu2+: 1ENa and 1JNa; (ii the external Cu2+-dependent internal Na concentration could be parsimoniously estimated, and (iii the site-specific clam gill potentials could be monitored. Here we provided a new approach to monitor waterborne metal toxicity to reduce the nationwide economic losses due to bans on harvesting of contaminated clam and the potential risks to the health of clams.

  8. The validity of a monitoring system based on routinely collected dairy cattle health data relative to a standardized herd check.

    Science.gov (United States)

    Brouwer, H; Stegeman, J A; Straatsma, J W; Hooijer, G A; Schaik, G van

    2015-11-01

    Dairy cattle health is often assessed during farm visits. However, farm visits are time consuming and cattle health is assessed at only one point in time. Moreover, farm visits are poorly comparable and/or repeatable when inspection is carried out by many different professionals. Many countries register cattle health parameters such as bulk milk somatic cell count (BMSCC) and mortality in central databases. A great advantage of such routinely available data is that they are uniformly gathered and registered throughout time. This makes comparison between dairy cattle herds possible and could result in opportunities to develop reliable tools for assessing cattle health based on routinely available data. In 2005, a monitoring system for the assessment of cattle health in Dutch dairy herds based on routinely available data was developed. This system had to serve as an alternative for the compulsory quarterly farm visits, which were implemented in 2002. However, before implementation of the alternative system for dairy cows, the validity of the data-based monitoring system and the compulsory quarterly visits relative to the real health status of the herd should be known. The aim of this study was to assess the validity of the data-based monitoring system and the compulsory quarterly visits relative to a standardized herd check for detecting dairy herds with health problems. The results showed that routinely available data can be used to develop an effective screening instrument for detecting herds with poor cattle health. Routinely available data such as cattle mortality and BMSCC that were used in this study had a significant association with animal-based measurements such as the general health impression of the dairy cows (including e.g. rumen fill and body condition). Our study supports the view that cattle health parameters based on routinely available data can serve as a tool for detecting herds with a poor cattle health status which can reduce the number of

  9. 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)

  10. 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

  11. Check My School

    OpenAIRE

    SHKABATUR, Jennifer

    2012-01-01

    Check My School (CMS) is a community monitoring project that aims to promote transparency and social accountability in the Philippine education sector by tracking the provision of services in public schools. The project uses a blended approach, which combines on-the-ground community monitoring with the use of information and communication technology (ICT). CMS had been initiated and design...

  12. 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 .

  13. 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 ...

  14. Intelligente valve monitor for on/off control valves in process engineering; Intelligenter Grenzsignalgeber fuer Auf/Zu-Armaturen in der Prozesstechnik

    Energy Technology Data Exchange (ETDEWEB)

    Karte, Thomas; Kiesbauer, Joerg; Schaertner, Karl-Bernd [SAMSON AG, Frankfurt (Germany)

    2009-07-01

    In the article entitled ''Smart and Reliable Whether On or Off - Valve Automation Trends'' [1] of December 2007, trends in the automation of On/Off control valves were illustrated. To meet the general demand for higher plant availability, superior reliability and lower costs, both the quality and quantity of automation systems used in this field continue to advance. In this article, an actual technical solution is described. For the first time, a manufacturer succeeded in building a microcomputerbased device that is exclusively supplied with a signal according to IEC 60947-5-6 (NAMUR signal) using a two-wire supply. As a result, a new generation of devices offering new opportunities can replace the classical solenoid valves and limit switches without requiring the cabling or signal levels to be changed. Plant operators additionally benefit from enhanced functions (e.g. self-tuning and diagnostics) that, until now, only positioners provided. (orig.)

  15. 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.

  16. Anticoagulation for Prosthetic Valves

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Kaneko

    2013-01-01

    Full Text Available Implantation of prosthetic valve requires consideration for anticoagulation. The current guideline recommends warfarin on all mechanical valves. Dabigatran is the new generation anticoagulation medication which is taken orally and does not require frequent monitoring. This drug is approved for treatment for atrial fibrillation and venous thromboembolism, but the latest large trial showed that this drug increases adverse events when used for mechanical valve anticoagulation. On-X valve is the new generation mechanical valve which is considered to require less anticoagulation due to its flow dynamics. The latest study showed that lower anticoagulation level lowers the incidence of bleeding, while the risk of thromboembolism and thrombosis remained the same. Anticoagulation poses dilemma in cases such as pregnancy and major bleeding event. During pregnancy, warfarin can be continued throughout pregnancy and switched to heparin derivative during 6–12 weeks and >36 weeks of gestation. Warfarin can be safely started after 1-2 weeks of discontinuation following major bleeding episode.

  17. 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)

  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. 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.

  20. 单向阀对双增压气路中气体流向影响的分析与研究%Research and Analysis on the Air Flow Direction Affected by Check Valve in Pressurization Gas Path of Two Electric Superchargers

    Institute of Scientific and Technical Information of China (English)

    姚春德; 韩伟强; 武炎; 侯亚帮; 徐成耀; 路平

    2012-01-01

    搭建由双电动增压器与单向阀组成的试验台架并模拟研究单向阀对双增压气路中气体流向的影响规律,以提高电动增压器的补气效率,从而增大公交车柴油机工况突变时的进气量,改善瞬态烟度.通过向两个电动增压器设定不同的转速,分别模拟公交车柴油机的废气涡轮增压器和附加用于急加速补气的电动增压器,研究并分析在气路上设置单向阀前后对双增压气路中气体流向的影响.试验结果表明,电动增压器的流量大于废气涡轮增压器的流量时,出口总流量在无单向阀时大致等于废气涡轮增压器提供的流量,增加电动增压器的流量不会改变出口总流量,电动增压器补气效率低,柴油机的进气量未得到改善.有单向阀时,出口总流量随电动增压器流量增加而增大,电动增压器补气效率高,柴油机的进气量增大;电动增压器的流量小于废气涡轮增压器的流量时,电动增压器与单向阀不影响出口总流量,出口总流量与有旁通气路无单向阀时相同,即电动增压器不工作时不影响原机的进气量.%A testing rig, consisting of two electric superchargers and a check valve, used to simulate and investigate the air flow direction affected by check valve in pressurization gas path is built. Through this way higher fill gas efficiency of electric supercharger can be achieved, which will give rise to more air inflow of diesel engine at its working condition mutation, improving transient FSN. By setting the speed of the two electric Superchargers respectively, one is used to simulate the turbocharger of the diesel engine of a bus and the other is used to simulate electric supercharger which supplys additional air for a sharp acceleration, to study the air flow direction affected by check valve in pressurization gas path. Testing results indicate that without the check valve, when the flow rate of the electric supercharger is larger than

  1. 贵—广Ⅱ宝安站极2Y3阀因无回报信号导致极2跳闸的故障分析及相关反措的建议%Analysis and Suggestions on Pole 2 Strip Caused by No Check Back Signal from Y3 Valve of GGH Baoan Station

    Institute of Scientific and Technical Information of China (English)

    李侠; 马振军

    2012-01-01

    The light triggered thyristor valves, which are directly triggered by laser, are used in Guizhou-Guangdong ±500 kV HVDC II power transmission lines. To ensure safe and reliable operation, thyristor voltage mornitors(TVM) are used to have on-line momitoring on each thyristor. By light cables, TVM sends real-time feedback signal to VBE, whose single-chip can judge the default of thyristor valves by reading such check back signals. When the number of default thyristors exceeds the number of thyristor redundancy, trip signal is sent. The author analyzes the default and provides the related suggestions on Pole 2 trip caused by no check back signal from Y3 valve of CCII Baoan station, 12th March, 2009 and 29 th May 2010.%中国贵—广Ⅱ±500 kV高压直流输电工程中均采用激光脉冲直接触发晶闸管的直接光控晶闸管换流阀(以下简称LTT阀).为了确保换流阀的安全可靠运行,对换流阀中的每个晶闸管用晶闸管电压监测电子线路(thyristor voltage momitoring,TVM)进行在线监测.TVM实时用回报信号将监测的结果通过光缆送往阀底部电子设备柜(VBE)中.VBE中的单片机监测系统根据回报信号分析判定晶闸管的故障,当阀内故障晶闸管教超过设计允许的冗余数,产生相应的跳闸信号.笔者就2009年3月12日和2010年5月29日贵—广Ⅱ宝安站极2 Y3阀因无回报信号导致极2跳闸的故障进行了分析,得出:跳闸故障并非由阀或VBE故障引起,而是由阀侧电压不稳定或扰动引起的结论,并提出相关反措的建议.

  2. Valve's Way

    Directory of Open Access Journals (Sweden)

    Phanish Puranam

    2015-06-01

    Full Text Available What can we learn from outliers? While statisticians rightly warn us against their non-representativeness, we believe it is also true that thinking carefully about what makes them atypical may improve our understanding of the typical case. This is the premise behind the Organization Zoo series. Valve Corporation (Valve is an unusual firm. It is a rare example of a firm that appears to operate without any formal hierarchy in its organization. What can we learn about the viability of authority hierarchies from Valve’s way of organizing? We wrote a brief account of Valve based on public information sources and asked several renowned organizational experts to comment on this unusual firm. We asked them to write a short commentary on what the Valve example means for organizational theorists and practitioners. Thankfully, they all accepted, and we are excited to present the results of their thinking in this first “exhibit” in the Organization Zoo.

  3. 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。

  4. 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 ...

  5. 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

  6. [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

  7. 49 CFR 236.383 - Valve locks, valves, and valve magnets.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Valve locks, valves, and valve magnets. 236.383... Inspection and Tests § 236.383 Valve locks, valves, and valve magnets. Valve locks on valves of the non-cut-off type shall be tested at least once every three months, and valves and valve magnets shall...

  8. 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.

  9. Valve's Way

    DEFF Research Database (Denmark)

    Foss, Nicolai Juul; Dobrajska, Magdalena

    2015-01-01

    Puranam and Håkonsson (2015) challenge us to ponder what we as organization design theorists make of Valve’s way (see also Jeppesen, 2008). We believe that Valve, in spite of its radical vision, does not represent a challenge to fundamental organization design theory and that it is questionable...... to 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...

  10. Excess flow shutoff valve

    Energy Technology Data Exchange (ETDEWEB)

    Kiffer, Micah S.; Tentarelli, Stephen Clyde

    2016-02-09

    Excess flow shutoff valve comprising a valve body, a valve plug, a partition, and an activation component where the valve plug, the partition, and activation component are disposed within the valve body. A suitable flow restriction is provided to create a pressure difference between the upstream end of the valve plug and the downstream end of the valve plug when fluid flows through the valve body. The pressure difference exceeds a target pressure difference needed to activate the activation component when fluid flow through the valve body is higher than a desired rate, and thereby closes the valve.

  11. Vacuum Valve

    CERN Multimedia

    1974-01-01

    This valve was used in the Intersecting Storage Rings (ISR) to protect against the shock waves that would be caused if air were to enter the vacuum tube. Some of the ISR chambers were very fragile, with very thin walls - a design required by physicists on the lookout for new particles.

  12. 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.

  13. Application of list style quality control method in implementation and monitoring of care check%清单式质量控制方式在护理查对制度执行监控中的应用

    Institute of Scientific and Technical Information of China (English)

    董雪云; 马辉; 陆利生

    2014-01-01

    Objective:To probe into the effect of list style quality control method for improving the rates of nursing checking standard,and aiming at correcting bad habits appearing in nurses carrying out the checking system, therefore to improve the effective checking standard rates.Methods: According to the requirements of nursing check system,on site inspections were carried out for nurses in 17 different surgical wards in hospital in different time periods and different operational links of the implementation of check system,to know about the non standard check behaviors of nurses.Timely feedback the problems and make quality control check list of nursing check,supervising and guide by one level quality control personnel. Results:After applying list type of quality control monitoring,the non standardized rate decent to 8.24% from 54.12%,the difference was statistically significant(P <0.05).Conclusion:The list type of quality control way is conductive for quality control personnels grasping the quality control focuses,and it is helpful for nurses developing good checking habits and improving care and check standardized rate.%[目的]探讨清单式质量控制方式对提高护理查对规范率的作用,旨在及时纠正护士执行查对制度的不良习惯,从而提高有效查对率。[方法]根据护理查对制度的要求,实地检查本院外科17个病区的护士在不同时间段及不同操作环节查对制度执行情况,了解护士不规范的查对行为。对存在问题及时反馈并制作护理查对质量控制清单,由一级质量控制员进行监督和指导。[结果]应用清单式质量控制方式监控后护理查对不规范率由54.12%下降至8.24%,差异有统计学意义(P<0.05)。[结论]清单式质量控制方式有利于质量控制员把握质量控制重点,有助于护士养成良好的查对习惯,提高护理查对规范率。

  14. 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

  15. 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.

  16. Aortic valve bypass

    DEFF Research Database (Denmark)

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

    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...

  17. 40 CFR 61.242-7 - Standards: Valves.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Standards: Valves. 61.242-7 Section 61... (Fugitive Emission Sources) § 61.242-7 Standards: Valves. (a) Each valve shall be monitored monthly to...) If an instrument reading of 10,000 ppm or greater is measured, a leak is detected. (c)(1) Any...

  18. 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 ...

  19. Automatic shutoff valve

    Science.gov (United States)

    Hawkins, S. F.; Overbey, C. W.

    1980-01-01

    Cellulose-sponge disk absorbs incoming water and expands with enough force to shut valve. When water recedes, valve opens by squeezing sponge dry to its original size. This direct mechanical action is considered more reliable than solenoid valve.

  20. Symbolic model checking APSL

    Institute of Scientific and Technical Information of China (English)

    Wanwei LIU; Ji WANG; Huowang CHEN; Xiaodong MA; Zhaofei WANG

    2009-01-01

    Property specification language (PSL) is a specification language which has been accepted as an industrial standard. In PSL, SEREs are used as additional formula constructs. In this paper, we present a variant of PSL, namely APSL, which replaces SEREs with finite automata. APSL and PSL are of the exactly same expressiveness. Then, we extend the LTL symbolic model checking algorithm to that of APSL, and then present a tableau based APSL verification technique, which can be easily implemented via the BDD based symbolic approach. Moreover, we implement an extension of NuSMV, and this adapted version supports symbolic model checking of APSL. Experimental results show that this variant of PSL can be efficiently verified. Henceforth, symbolic model checking PSL can be carried out by a transformation from PSL to APSL and symbolic model checking APSL.

  1. 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 ...

  2. Adjustable safety relief valve

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, W.L.

    1990-06-12

    This patent describes a pressure relief valve having a relief set pressure. It comprises: a valve body having a fluid inlet and outlet, a spherical, metal valve seat associated with the inlet and a valve member comprising at least a portion of a spherical,metal ball attached to a ball holding element, the valve member being biased against the valve seat and thus providing a metal-to-metal seal preventing the passage of fluids past the valve seat when the fluid pressure in the inlet is below the relief pressure setting of the valve.

  3. 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....

  4. NHS Health Checks

    OpenAIRE

    Abdalrahman, Bayad; Soljak, Michael

    2014-01-01

    Cardiovascular disease is the leading cause of mortality and morbidity worldwide. In England, the government has adopted a population-wide prevention program for cardiovascular disease, the NHS Health Check program. The program has sparked controversies over the evidence base and feasibility of implementation. We aim to provide an update on the debate and program implementation. In conclusion, the evidence base for the NHS Health Check program has a number of uncertainties and program deliver...

  5. 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.

  6. 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.

  7. Valve-in-valve-in-valve: Treating endocarditis of a transcatheter heart valve.

    Science.gov (United States)

    Nguyen, Caroline; Cheong, Adrian P; Himbert, Dominique

    2015-10-01

    Transcatheter heart valve endocarditis is a rare, but life threatening complication. We describe the case of a patient who was successfully treated by transcatheter aortic valve-in-valve-in-valve replacement with a favorable 1-year outcome, despite severe early complications.

  8. 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.

  9. 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.

  10. 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.

  11. Valve-in-Valve Replacement Using a Sutureless Aortic Valve

    Science.gov (United States)

    Dohmen, Pascal M.; Lehmkuhl, Lukas; Borger, Michael A.; Misfeld, Martin; Mohr, Friedrich W.

    2016-01-01

    Patient: Female, 61 Final Diagnosis: Tissue degeneration Symptoms: Dyspnea Medication: — Clinical Procedure: Redo valve replacement Specialty: Surgery Objective: Rare disease Background: We present a unique case of a 61-year-old female patient with homograft deterioration after redo surgery for prosthetic valve endocarditis with root abscess. Case Report: The first operation was performed for type A dissection with root, arch, and elephant trunk replacement of the thoracic aorta. The present re-redo surgery was performed as valve-in-valve with a sutureless aortic biopros-thesis. The postoperative course was uneventful and the patient was discharged on day 6. Conclusions: The current case report demonstrates that sutureless bioprostheses are an attractive option for surgical valve-in-valve procedures, which can reduce morbidity and mortality. PMID:27694795

  12. Partial model checking

    DEFF Research Database (Denmark)

    Andersen, Henrik Reif

    1995-01-01

    A major obstacle in applying finite-state model checking to the verification of large systems is the combinatorial explosion of the state space arising when many loosely coupled parallel processes are considered. The problem also known as the state-explosion problem has been attacked from various...... sides. This paper presents a new approach based on partial model checking where parts of the concurrent system are gradually removed while transforming the specification accordingly. When the intermediate specifications constructed in this manner can be kept small, the state-explosion problem is avoided...

  13. Checking BEBC superconducting magnet

    CERN Multimedia

    1974-01-01

    The superconducting coils of the magnet for the 3.7 m Big European Bubble Chamber (BEBC) had to be checked, see Annual Report 1974, p. 60. The photo shows a dismantled pancake. By December 1974 the magnet reached again the field design value of 3.5 T.

  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. 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

  16. Check Verbraucherpolitik und Verbraucherbeteiligung

    DEFF Research Database (Denmark)

    Hagen, Kornelia; Micklitz, Hans-W.; Oehler, Andreas;

    2013-01-01

    The paper discusses the opportunities for an empirically grounded decision support system as an instrument for independent and scientifically based consumer policy consulting. To date, consumer policy is dominated by the information paradigm and the leitbild of the rational, sovereign...... and information-seeking consumer. Yet, both everyday practice and research in behavioural economics show that this view lacks empirical ground. In fact, there are different consumer types and different forms of rationalities at work. Effective consumer policy making should be based on the empirically revealed...... an empirically based “Check Consumer Policy and Consumer Participation” as a systematic decision and evaluation tool for policy makers. This check should be independent from the government and should be grounded on an empirical view of the consumer. Consumer policy tools should be tested with real consumers...

  17. 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 ...

  18. 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 ...

  19. Aerodynamic Shutoff Valve

    Science.gov (United States)

    Horstman, Raymond H.

    1992-01-01

    Aerodynamic flow achieved by adding fixed fairings to butterfly valve. When valve fully open, fairings align with butterfly and reduce wake. Butterfly free to turn, so valve can be closed, while fairings remain fixed. Design reduces turbulence in flow of air in internal suction system. Valve aids in development of improved porous-surface boundary-layer control system to reduce aerodynamic drag. Applications primarily aerospace. System adapted to boundary-layer control on high-speed land vehicles.

  20. 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...

  1. 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.

  2. Proportional directional valve based automatic steering system for tractors

    Institute of Scientific and Technical Information of China (English)

    Jin-yi LIU; Jing-quan TAN; En-rong MAO; Zheng-he SONG; Zhong-xiang ZHU‡

    2016-01-01

    Most automatic steering systems for large tractors are designed with hydraulic systems that run on either constant flow or constant pressure. Such designs are limited in adaptability and applicability. Moreover, their control valves can unload in the neutral position and eventually lead to serious hydraulic leakage over long operation periods. In response to the problems noted above, a multifunctional automatic hydraulic steering circuit is presented. The system design is composed of a 5-way-3-position proportional directional valve, two pilot-controlled check valves, a pressure-compensated directional valve, a pressure-compensated flow regulator valve, a load shuttle valve, and a check valve, among other components. It is adaptable to most open-center systems with constant flow supply and closed-center systems with load feedback. The design maintains the lowest pressure under load feedback and stays at the neutral position during unloading, thus meeting the requirements for steering. The steering controller is based on proportional-integral-derivative (PID) running on a 51-microcontroller-unit master control chip. An experimental platform is developed to establish the basic characteristics of the system subject to stepwise inputs and sinusoi-dal tracking. Test results show that the system design demonstrates excellent control accuracy, fast response, and negligible leak during long operation periods.

  3. Check-up Measurement (update). Deliverable D5.22

    NARCIS (Netherlands)

    Holtzer, A.C.G.; Giessen, A.M.D. van der; Djurica, M.

    2015-01-01

    This deliverable D5.22 presents the GEN6 check-up measurement. It describes the most prominent outcomes of the GEN6 project up to this point in time. The check-up measurement helps to focus the monitoring towards the most relevant achievements of the project, such that an efficient and well-targeted

  4. 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 ...

  5. Check, check, double check: checking the autopilot causes distrust : Experimental studies on the effects of compulsive perseveration

    NARCIS (Netherlands)

    Dek, E.C.P.

    2015-01-01

    Obsessive-compulsive disorder (OCD) is characterized by persistent doubt. The majority of patients with OCD engage in repeated checking to reduce these feelings of uncertainty. However, numerous studies demonstrated that repetitive behavior ironically increases uncertainty: perseverative checking in

  6. 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...

  7. 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...

  8. Safety of the adjustable pressure ventricular valve in magnetic resonance imaging: problems and solutions

    Energy Technology Data Exchange (ETDEWEB)

    Fransen, P.; Thauvoy, C. (Clinique Universitaire St. Luc, Brussels (Belgium). Neurosurgery Service); Dooms, G. (Clinique Universitaire St. Luc, Brussels (Belgium). Neuroradiology Service)

    1992-11-01

    We performed magnetic resonance imaging in 30 patients with hydrocephalus with Sophy adjustable pressure valves (PAVS). A pressure check following the MRI study showed a significant proportion with pressure valve changes, which could easily be readjusted by percutaneous manipulation. The value of the PAVS and its safety during MRI examinations are discussed. (orig.).

  9. 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

  10. 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.)

  11. 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.

  12. 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.

  13. ENERGY EFFICIENT AND SAFE VALVE TESTING UNIT USING WIRELESS TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    V. Dhivya

    2013-04-01

    Full Text Available The valve testing unit is a high pressure test equipment to test the valve manufactured in industries. Valves are tested to ensure that they sustain high pressure in the range of 10000 to 15000 PSI for the required amount of time without any leakage. It has few drawbacks such as inefficient usage of power, fatal accidents due to the proximity of the users with the testing unit to note the valve pressure during operation. It is much dangerous for the industry personnel to note the valve pressure for every minute during operation. There are chances of bolts fitted in the valve thrown away due to the issues in the bolt fittings and the immense pressure inside the valve. Therefore in order to avoid fatal accidents andto improve the industrial safety an efficient valve testing unit is designed and developed using ZigBee wireless transmission technology. The proposed efficient pressure monitoring unit uses emerging technologies like ZigBee, RFID along with ARM 7 processor. The proposed system uses LabVIEW software to develop the monitoring unit in PC. ZigBee wireless transmission technology is used for remote monitoring of valve pressure for every minute. RFID module is used for uniquely identifying the valve and to track the test results. The proposed unit saves energy by sending a signal to turn off the air driven booster pump once the prescribed pressure level is reached. Theproposed unit also indicates the oil level of the test unit which avoids the manual intervention to verify the oil level and also detects issues in the bolts fitted in the valve by using a distance sensor which is to avoid fatal accidents by stopping the valve testing unit.

  14. Valve selection in aortic valve endocarditis

    Science.gov (United States)

    Zubrytska, Yana

    2016-01-01

    Aortic prosthetic valve endocarditis (PVE) is a potentially life-threatening disease. Mortality and incidence of infective endocarditis have been reduced in the past 30 years. Medical treatment of aortic PVE may be successful in patients who have a prompt response after antibiotic treatment and who do not have prosthetic dysfunction. In advanced stages, antibiotic therapy alone is insufficient to control the disease, and surgical intervention is necessary. Surgical treatment may be lifesaving, but it is still associated with considerable morbidity and mortality. The aim of surgery is to perform a radical excision of all infected and necrotic tissue, reconstruction of the left ventricle outflow tract, and replacement of the aortic valve. There is no unanimous consensus on which is the optimal prosthesis to implant in this context, and several surgical techniques have been suggested. We aim to analyze the efficacy of the surgical treatment and discuss the issue of valve selection in patients with aortic valve endocarditis.

  15. 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

  16. 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

  17. Transcatheter aortic valve implantation in failed bioprosthetic surgical valves

    DEFF Research Database (Denmark)

    Dvir, Danny; Webb, John G; Bleiziffer, Sabine;

    2014-01-01

    IMPORTANCE: Owing to a considerable shift toward bioprosthesis implantation rather than mechanical valves, it is expected that patients will increasingly present with degenerated bioprostheses in the next few years. Transcatheter aortic valve-in-valve implantation is a less invasive approach...... for patients with structural valve deterioration; however, a comprehensive evaluation of survival after the procedure has not yet been performed. OBJECTIVE: To determine the survival of patients after transcatheter valve-in-valve implantation inside failed surgical bioprosthetic valves. DESIGN, SETTING......, AND PARTICIPANTS: Correlates for survival were evaluated using a multinational valve-in-valve registry that included 459 patients with degenerated bioprosthetic valves undergoing valve-in-valve implantation between 2007 and May 2013 in 55 centers (mean age, 77.6 [SD, 9.8] years; 56% men; median Society of Thoracic...

  18. Model Checking as Static Analysis

    DEFF Research Database (Denmark)

    Zhang, Fuyuan

    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...... 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......-calculus can be encoded as the intended model of SFP. Our research results have strengthened the link between model checking and static analysis. This provides a theoretical foundation for developing a unied tool for both model checking and static analysis techniques....

  19. [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

  20. 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.

  1. 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...

  2. Biological heart valves.

    Science.gov (United States)

    Ciubotaru, Anatol; Cebotari, Serghei; Tudorache, Igor; Beckmann, Erik; Hilfiker, Andres; Haverich, Axel

    2013-10-01

    Cardiac valvular pathologies are often caused by rheumatic fever in young adults, atherosclerosis in elderly patients, or by congenital malformation of the heart in children, in effect affecting almost all population ages. Almost 300,000 heart valve operations are performed worldwide annually. Tissue valve prostheses have certain advantages over mechanical valves such as biocompatibility, more physiological hemodynamics, and no need for life-long systemic anticoagulation. However, the major disadvantage of biological valves is related to their durability. Nevertheless, during the last decade, the number of patients undergoing biological, rather than mechanical, valve replacement has increased from half to more than three-quarters for biological implants. Continuous improvement in valve fabrication includes development of new models and shapes, novel methods of tissue treatment, and preservation and implantation techniques. These efforts are focused not only on the improvement of morbidity and mortality of the patients but also on the improvement of their quality of life. Heart valve tissue engineering aims to provide durable, "autologous" valve prostheses. These valves demonstrate adaptive growth, which may avoid the need of repeated operations in growing patients.

  3. 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...

  4. A piezoelectrically actuated ball valve

    Science.gov (United States)

    Erwin, L. R.; Schwartz, H. W.; Teitelbaum, B. R.

    1972-01-01

    Bimorph strip composed of two layers of poled piezoelectric ceramic material closes and opens valve. Strip performs like capacitator, allowing initial inrush of current when valve is energized and then only small leakage current flows as valve remains energized.

  5. 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 ...

  6. 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...

  7. 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 ...

  8. Transaction management with integrity checking

    DEFF Research Database (Denmark)

    Martinenghi, Davide; Christiansen, Henning

    2005-01-01

    , 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...

  9. Checks and Controls in Spreadsheets

    CERN Document Server

    O'Beirne, Patrick

    2009-01-01

    Spreadsheets that are informally created are harder to test than they should be. Simple cross-foot checks or being easily readable are modest but attainable goals for every spreadsheet developer. This paper lists some tips on building self-checking into a spreadsheet in order to provide more confidence to the reader that a spreadsheet is robust.

  10. 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

  11. Shutoff and throttling valve

    Science.gov (United States)

    Hays, L. G.

    1974-01-01

    Leaktight shutoff, precise flow control, and very low pressure drop are incorporated in all-metal valve designed for operation under extreme temperatures. Valve constructed with refractory metal is intended for control of high-temperature liquid cesium, but has applications related to control of high- and low-temperature liquids and gases.

  12. 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.

  13. 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.

  14. 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

  15. Computational valve plate design

    Science.gov (United States)

    Kalbfleisch, Paul

    Axial piston machines are widely used in many industries for their designs compactness, flexibility in power transfer, variable flow rate, and high efficiencies as compared to their manufacturing costs. One important component of all axial piston machines that is a very influential on the performance of the unit is the valve plate. The aim of this research is to develop a design methodology that is general enough to design all types of valve plates and the simple enough not to require advanced technical knowledge from the user. A new style of valve plate designs has been developed that comprehensively considers all previous design techniques and does not require significant changes to the manufacturing processes of valve plates. The design methodology utilizes a previously developed accurate computer model of the physical phenomenon. This allows the precise optimization of the valve plate design through the use of simulations rather than expensive trial and error processes. The design of the valve plate is clarified into the form of an optimization problem. This formulation into an optimization problem has motivated the selection of an optimization algorithm that satisfies the requirements of the design. The proposed design methodology was successfully tested in a case study in the shown to be very successful in improving required performance of the valve plate design.

  16. 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

  17. 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.

  18. 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 ...

  19. Body checking behaviors in men.

    Science.gov (United States)

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

    2009-06-01

    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 concern, symptoms of muscle dysmorphia, depression, negative affect, and APED use. Body checking predicted APED use and uniquely accounted for the largest amount of variance in Muscle Dysmorphic Disorder Inventory (MDDI) scores (16%). Findings support the view that body checking is an important construct in male body image, muscle dysmorphia, and body change strategies and suggest a need for further research. PMID:19482568

  20. 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...

  1. 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...

  2. Danfos: Thermostatic Radiator Valves

    DEFF Research Database (Denmark)

    Gregersen, Niels; Oliver, James; Hjorth, Poul G.

    2000-01-01

    This problem deals with modelling the flow through a typical Danfoss thermostatic radiator valve.Danfoss is able to employ Computational Fluid Dynamics (CFD) in calculations of the capacity of valves, but an experienced engineer can often by rules of thumb "guess" the capacity, with a precision...... similar to the one achieved by the expensive and time-consuming CFD calculations. So CFD is only used in case of entirely new designs or where a very detailed knowledge of the flow is required. Even though rules of thumb are useful for those, who have developed them, Danfoss needs an objective and general...... method that can be used to predict the performance of valves....

  3. 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.

  4. 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 ...

  5. 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...

  6. 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...

  7. 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

  8. 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

  9. 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 ...

  10. 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...... countries. METHODS: A multi-institutional, non-randomized, retrospective analysis was conducted among 2,932 patients who underwent AVR surgery at seven tertiary cardiac surgery centers throughout Europe. Demographic and perioperative variables including valve size and type, body surface area (BSA) and early......: Prostheses with diameter valve size was also smaller in southern compared to northern European patients (21.6 +/- 2.1 mm versus 23.4 +/- 2.2 mm, p

  11. 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

  12. Automatization and familiarity in repeated checking

    NARCIS (Netherlands)

    Dek, Eliane C P; van den Hout, Marcel A.; Giele, Catharina L.; Engelhard, Iris M.

    2014-01-01

    Repeated checking paradoxically increases memory uncertainty. This study investigated the underlying mechanism of this effect. We hypothesized that as a result of repeated checking, familiarity with stimuli increases, and automatization of the checking procedure occurs, which should result in decrea

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

    Science.gov (United States)

    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 feedback at predetermined times. The present study sought to add to the literature by examining the relative contributions of the teacher-feedback components of check-in/check-out via the use of a component analysis. Working with 4 children in a general education setting, we first evaluated the effectiveness of the procedure using reversal designs. Next, we systematically removed teacher-feedback components to assess effects on problem behavior and academic engagement. For 3 of 4 participants, we were able to remove all teacher-feedback sessions and the point card; for the 4th participant, we removed only 2 of 3 teacher-feedback sessions due to time constraints. PMID:21709787

  14. 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)

  15. 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)

  16. 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.

  17. Design and theoretical analysis of a sliding valve distribution radial piston pump

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Guo; Shengdun, Zhao; Yanghuiwen, Yu [Xian Jiaotong University, Xian (China); Peng, Shang [Xian Engineering University of Armed Police Force, Xian (China)

    2016-01-15

    A Sliding valve distribution radial piston pump (SVDRPP) is presented. In this pump, a new distribution method that uses sliding valves to distribute oil for the piston chambers is developed. With this design, the disadvantages brought by the distribution shaft and the check valves (traditional distribution mechanisms), such as the poor stress state of the shaft and the energy waste for opening the check valves, are expected to be eliminated. In addition, a method of using pressure oil to accomplish the returning stroke of the piston is also proposed, which could be used to replace the usage of springs along with their shortcomings. A pump with five pistons is designed as an example to elaborate the structure and the working principle of SVDRPP. Furthermore, the flow characteristics of SVDRPP are studied, and the formulas of the displacement, the average flow rate and the instantaneous flow rate are deduced.

  18. Model Checking Linearizability via Refinement

    Science.gov (United States)

    Liu, Yang; Chen, Wei; Liu, Yanhong A.; Sun, Jun

    Linearizability is an important correctness criterion for implementations of concurrent objects. Automatic checking of linearizability is challenging because it requires checking that 1) all executions of concurrent operations be serializable, and 2) the serialized executions be correct with respect to the sequential semantics. This paper describes a new method to automatically check linearizability based on refinement relations from abstract specifications to concrete implementations. Our method avoids the often difficult task of determining linearization points in implementations, but can also take advantage of linearization points if they are given. The method exploits model checking of finite state systems specified as concurrent processes with shared variables. Partial order reduction is used to effectively reduce the search space. The approach is built into a toolset that supports a rich set of concurrent operators. The tool has been used to automatically check a variety of implementations of concurrent objects, including the first algorithms for the mailbox problem and scalable NonZero indicators. Our system was able to find all known and injected bugs in these implementations.

  19. [Technologies for cardiac valve prostheses].

    Science.gov (United States)

    Nakano, Kiyoharu

    2009-07-01

    To show the technological development of cardiac valve prostheses, a historical review of both mechanical and biological valve prostheses and a current overview of modern cardiac valve devices are provided. Scince the 1st implantation of Starr-Edwards ball valve in 1960, both mechanical and biological valve prostheses have advanced. The valve design, the material of the leaflet and the hausing of mechanical prostheses have improved. Currently, the majority of the mechanical prostheses are bileaflet tilting disc valves made of pyrolytic carbon, which is antithromboembolic. However, anticoagulation therapy with warfarin is still required. As for the bioprostheses, although the fixation and anti-mineralization methods of the tissues improved, the durability of these valves is still limited. For the material of the current biological valves, the porcine aortic valve or bovine pericardium are used. The tissues are fixed by non-pressure or low-pressure method in glutaraldehyde solution. A stented and non-stented valves are available. Epoch-making events in this field are the implantation of new bioprosthetic valves using tissue engineering methods and the development of the transcatheter valve replacement therapies.

  20. 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.

  1. 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

  2. Transcatheter Aortic Valve Replacement for Degenerative Bioprosthetic Surgical Valves

    DEFF Research Database (Denmark)

    Dvir, Danny; Webb, John; Brecker, Stephen;

    2012-01-01

    Transcatheter aortic valve-in-valve implantation is an emerging therapeutic alternative for patients with a failed surgical bioprosthesis and may obviate the need for reoperation. We evaluated the clinical results of this technique using a large, worldwide registry.......Transcatheter aortic valve-in-valve implantation is an emerging therapeutic alternative for patients with a failed surgical bioprosthesis and may obviate the need for reoperation. We evaluated the clinical results of this technique using a large, worldwide registry....

  3. 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.

  4. Compositional and Quantitative Model Checking

    DEFF Research Database (Denmark)

    Larsen, Kim Guldstrand

    2010-01-01

    on the existence of a quotient construction, allowing a property phi of a parallel system phi/A to be transformed into a sufficient and necessary quotient-property yolA to be satisfied by the component 13. Given a model checking problem involving a network Pi I and a property yo, the method gradually move (by...

  5. 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.

  6. 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 ...

  7. 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...

  8. 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 ...

  9. 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 ...

  10. Safety valve for offshore borehole

    Energy Technology Data Exchange (ETDEWEB)

    McGill, H.L.; Randermann, E. Jr.; Musik, O.J.

    1977-10-06

    The invention concerns a new and improved submarine safety valve with a valve element which rotate, which can be used, in emergencies, to separate the wound-up piping which extends into the borehole and to close the production line.

  11. 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 ...

  12. Josephson magnetic rotary valve

    Energy Technology Data Exchange (ETDEWEB)

    Soloviev, I. I. [Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow (Russian Federation); Lukin Scientific Research Institute of Physical Problems, Zelenograd, Moscow (Russian Federation); Klenov, N. V. [Physics Department, Moscow State University, Moscow (Russian Federation); Lukin Scientific Research Institute of Physical Problems, Zelenograd, Moscow (Russian Federation); Bakurskiy, S. V. [Physics Department, Moscow State University, Moscow (Russian Federation); Moscow Institute of Physics and Technology, State University, Dolgoprudniy, Moscow region (Russian Federation); Faculty of Science and Technology and MESA+, Institute for Nanotechnology, University of Twente, Enschede (Netherlands); Bol' ginov, V. V.; Ryazanov, V. V. [Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka (Russian Federation); National University of Science and Technology MISiS, Moscow (Russian Federation); Kupriyanov, M. Yu. [Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow (Russian Federation); Moscow Institute of Physics and Technology, State University, Dolgoprudniy, Moscow region (Russian Federation); Golubov, A. A. [Moscow Institute of Physics and Technology, State University, Dolgoprudniy, Moscow region (Russian Federation); Faculty of Science and Technology and MESA+, Institute for Nanotechnology, University of Twente, Enschede (Netherlands)

    2014-12-15

    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.

  13. 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

  14. 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

  15. 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

  16. SAFETY SHUTOFF VALVE

    DEFF Research Database (Denmark)

    2010-01-01

    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...... resulted from collision or effusion. A static tower has been applied for the main core of this part of the valve which loses balance state under the effect of collision and bounces to the neighboring part, which results in release of the catch and blockage of the gas passing channel....

  17. 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)

  18. Enteroenteroanastomosis near adjacent ileocecal valve in infants

    Institute of Scientific and Technical Information of China (English)

    Wei-Wei Jiang; Xiao-Qun Xu; Qi-Ming Geng; Jie Zhang; Huan Chen; Xiao-Feng Lv; Chang-Gui Lu

    2012-01-01

    AIM:To investigate the feasibility and the effectiveness of ileoileostomy in the region adjacent to the ileocecal valve,which can retain the ileocecal valve in infants.METHODS:This is a retrospective review of 48 patients who underwent ileoileostomy in the region adjacent to the ileocecal valve (group 1) and 34 patients who underwent ileocecal resections and ileotransversanastomosis (group 2).Patients were monitored for the time to flatus,resumption of eating,length of hospital stay after surgery,serum total bile acid,vitamin B12 and postoperative complications.RESULTS:The time to flatus,time until resumption of eating and post-operative length of hospital stay showed no statistically significant differences between the two groups.Serum total bile acid and vitamin B12 were not significantly different between the two groups at post-operative day 1 and day 3,but were significantly decreased at 1 wk after operation in group 2.None of the patients died or suffered from stomal leak in these two groups.However,the incidence of diarrhea,intestinal infection,disturbance of acid-base balance and water-electrolytes in group 1 was lower than in group 2.CONCLUSION:Ileoileostomy in the region adjacent to the ileocecal valve is safe and results in fewer complications than ileotransversanastomosis in infants.

  19. 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...

  20. Formal Checking of Multiple Firewalls

    Directory of Open Access Journals (Sweden)

    Nihel Ben Youssef

    2012-05-01

    Full Text Available When enterprises deploy multiple firewalls, a packet may be examined by different sets of firewalls. It has been observed that the resulting complex firewall network is highly error prone and causes serious security holes. Hence, automated solutions are needed in order to check its correctness. In this paper, we propose a formal and automatic method for checking whether multiple firewalls react correctly with respect to a security policy given in a high level declarative language. When errors are detected, some useful feedback is returned in order to correct the firewall configurations. Furthermore, we propose a priority-based approach to ensure that no incoherencies exist within the security policy. We show that our method is both correct and complete. Finally, it has been implemented in a prototype of verifier based on a satisfiability solver modulo theories. Experiment conducted on relevant case studies demonstrates the efficiency of our approach.

  1. An electrochemical active valve

    NARCIS (Netherlands)

    Neagu, C.R.; Gardeniers, J.G.E.; Elwenspoek, M.; Kelly, J.J.

    1997-01-01

    A novel electrochemical microactuator was developed, which operates as an active valve. The microactuator consists of an electrochemical cell and a membrane that deflects because of the pressure of oxygen gas generated by electrolysis. Relatively large pressures (up to tens of bars) can be reached w

  2. 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.

  3. 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.

  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. 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.

  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. 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.

  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. Variable reluctance proximity sensors for cryogenic valve position indication

    Science.gov (United States)

    Cloyd, R. A.

    1982-01-01

    A test was conducted to determine the performance of a variable reluctance proximity sensor system when installed in a space shuttle external tank vent/relief valve. The sensors were used as position indicators. The valve and sensors were cycled through a series of thermal transients; while the valve was being opened and closed pneumatically, the sensor's performance was being monitored. During these thermal transients, the vent valve was cooled ten times by liquid nitrogen and two times by liquid hydrogen. It was concluded that the sensors were acceptable replacements for the existing mechanical switches. However, the sensors need a mechanical override for the target similar to what is presently used with the mechanical switches. This override could insure contact between sensor and target and eliminate any problems of actuation gap growth caused by thermal gradients.

  10. 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.

  11. Valve-in-valve transcatheter aortic valve implantation overcoming hostile anatomy: Evolut R for the treatment of Mitroflow bioprosthesis dysfunction.

    Science.gov (United States)

    Ruparelia, Neil; Colombo, Antonio; Latib, Azeem

    2016-10-01

    Redo surgery is regarded as the first-line treatment option for patients presenting with prosthetic valve degeneration. However, many patients have concomitant co-morbidities and this option is associated with significant risk. Transcatheter valve-in-valve implantation is an alternative strategy depending on the bioprosthetic valve that is being treated. The Sorin Mitroflow bioprosthetic aortic valve has been regarded as a contraindication to valve-in-valve treatment due to the high risk of coronary obstruction. We here present the case of a patient with small peripheral vasculature who underwent successful transfemoral valve-in-valve implantation and subsequently discuss the challenges and technical aspects that require consideration.

  12. Considerations of EnvironmentaI Protection Check and Acceptance Monitoring for the Completed Domestic Animals Slaughter Industry%畜类屠宰加工行业竣工环保验收监测的要点

    Institute of Scientific and Technical Information of China (English)

    丁明刚; 谭秀梅; 孟春晓

    2014-01-01

    With the continuous development of economy , domestic animals slaughter industry was constantly developed.At the same time , it brought a series of environmental problems.According to the features of the domestic animals slaughter industry , the problems of environmentaI protection check and acceptance construction project were summarized and stated , and the references to the completion inspection project were provided.%随着我国经济持续发展,屠宰及肉类加工行业发展势头良好,行业规模稳步扩大,在满足消费需求的同时,也带来了一系列环保问题。根据畜类屠宰加工行业的特点,本文归纳并阐述了该类项目竣工环境保护验收监测中应重点关注的的几个问题,从而为这类项目的竣工环保验收监测工作提供参考。

  13. 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 ...

  14. 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.

  15. Treatment of aortic stenosis with a self-expanding transcatheter valve

    DEFF Research Database (Denmark)

    Linke, Axel; Wenaweser, Peter; Gerckens, Ulrich;

    2014-01-01

    AIM: Transcatheter aortic valve implantation has become an alternative to surgery in higher risk patients with symptomatic aortic stenosis. The aim of the ADVANCE study was to evaluate outcomes following implantation of a self-expanding transcatheter aortic valve system in a fully monitored, mult...

  16. Statistical Model Checking of Rich Models and Properties

    DEFF Research Database (Denmark)

    Poulsen, Danny Bøgsted

    Software is in increasing fashion embedded within safety- and business critical processes of society. Errors in these embedded systems can lead to human casualties or severe monetary loss. Model checking technology has proven formal methods capable of finding and correcting errors in software...... 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....... However, software is approaching the boundary in terms of the complexity and size that model checking can handle. Furthermore, software systems are nowadays more frequently interacting with their environment hence accurately modelling such systems requires modelling the environment as well - resulting...

  17. Tricuspid Valve Replacement, Mechnical vs. Biological Valve, Which Is Better?

    Directory of Open Access Journals (Sweden)

    Haitham Akram Altaani

    2013-06-01

    Full Text Available Background: The initial trial in tricuspid surgery is repair; however, replacement is done whenever the valve is badly diseased. Tricuspid valve replacement comprises 1.7% of all tricuspid valve surgeries. Materials and Methods: The present retrospective study was performed using the medical records of 21 cases who underwent tricuspid valve replacement from January 2002 until the end of December 2010. The mean age of the participants was 52.3±8.8 years and 66.7% were females. In addition, tricuspid valve replacement was associated with mitral valve surgery, aortic valve surgery, and both in 14.3%, 4.8%, and 33.3% of the cases, respectively. Yet, isolated tricuspid valve replacement and redo surgery were performed in 10 cases (47.6% and 8 cases (38.1%, respectively. Besides, trial of repair was done in 14 cases (66.7%. Moreover, biological and mechanical valves were used in 76.2% and 23.8% of the patients, respectively. Results: According to the results, early mortality was 23.8% and one year survival was 66.7%. Moreover, early mortality was caused by right ventricular failure, multiorgan failure, medistinitis, and intracerbral bleeding in 42%, 28.6%, 14.3%, and 14.3% of the cases, respectively. In addition, 57.1% of the deaths had occurred in the cases where the biological valve was used, while 42.9% of the deaths had taken place where the mechanical one was utilized. Conclusions: The patients who require tricuspid valve replacement are usually high risk surgical candidates with early and long term mortality. The findings of the current study showed no significant hemodynamic difference between mechanical and biological valves.

  18. 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.

  19. Posterior Urethral Valves

    Directory of Open Access Journals (Sweden)

    Steve J. Hodges

    2009-01-01

    Full Text Available The most common cause of lower urinary tract obstruction in male infants is posterior urethral valves. Although the incidence has remained stable, the neonatal mortality for this disorder has improved due to early diagnosis and intensive neonatal care, thanks in part to the widespread use of prenatal ultrasound evaluations. In fact, the most common reason for the diagnosis of posterior urethral valves presently is the evaluation of infants for prenatal hydronephrosis. Since these children are often diagnosed early, the urethral obstruction can be alleviated rapidly through catheter insertion and eventual surgery, and their metabolic derangements can be normalized without delay, avoiding preventable infant mortality. Of the children that survive, however, early diagnosis has not had much effect on their long-term prognosis, as 30% still develop renal insufficiency before adolescence. A better understanding of the exact cause of the congenital obstruction of the male posterior urethra, prevention of postnatal bladder and renal injury, and the development of safe methods to treat urethral obstruction prenatally (and thereby avoiding the bladder and renal damage due to obstructive uropathy are the goals for the care of children with posterior urethral valves[1].

  20. Supramolecular spin valves.

    Science.gov (United States)

    Urdampilleta, M; Klyatskaya, S; Cleuziou, J-P; Ruben, M; Wernsdorfer, W

    2011-07-01

    Magnetic molecules are potential building blocks for the design of spintronic devices. Moreover, molecular materials enable the combination of bottom-up processing techniques, for example with conventional top-down nanofabrication. The development of solid-state spintronic devices based on the giant magnetoresistance, tunnel magnetoresistance and spin-valve effects has revolutionized magnetic memory applications. Recently, a significant improvement of the spin-relaxation time has been observed in organic semiconductor tunnel junctions, single non-magnetic molecules coupled to magnetic electrodes have shown giant magnetoresistance and hybrid devices exploiting the quantum tunnelling properties of single-molecule magnets have been proposed. Herein, we present an original spin-valve device in which a non-magnetic molecular quantum dot, made of a single-walled carbon nanotube contacted with non-magnetic electrodes, is laterally coupled through supramolecular interactions to TbPc(2) single-molecule magnets (Pc=phthalocyanine). Their localized magnetic moments lead to a magnetic field dependence of the electrical transport through the single-walled carbon nanotube, resulting in magnetoresistance ratios up to 300% at temperatures less than 1 K. We thus demonstrate the functionality of a supramolecular spin valve without magnetic leads. Our results open up prospects of new spintronic devices with quantum properties. PMID:21685902

  1. 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.

  2. 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.

  3. Monitoring solar gain. Performance of an industrial-scale solar thermal power system; Anlagenertraege kontrollieren. Betriebsergebnisse einer solarthermischen Grossanlage

    Energy Technology Data Exchange (ETDEWEB)

    Haug, W.; Rittmann, B. [Fachhochschule Aalen (Germany)

    2001-05-01

    The Carl-Schneider students' hostel of Aalen Technical University gets its warm water from a solar systems. A faulty return valve was detected during a routine check, and the authors therefore stress the need for continuous monitoring of solar systems. [German] Eine Solarwaermeanlage versorgt das Carl-Schneider-Studentenheim der Fachhochschule Aalen mit Warmwasser. Sie funktioniert tadellos. Dem war nicht immer so. Ein klemmendes Rueckschlagventil waere wohl nie entdeckt worden, haette es nicht eine Abnahmemessung gegeben. Die Autoren, Professoren an der Fachhochschule, plaedieren deshalb fuer eine kontinuierliche Ueberwachung von Solaranlagen. (orig.)

  4. 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...

  5. 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.

  6. 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

    BACKGROUND: Transcatheter aortic valve implantation (TAVI) is an advancing mode of treatment for inoperable or high-risk patients with aortic stenosis. Prosthetic valve endocarditis (PVE) after TAVI is a serious complication, but only limited data exist on its incidence, outcome, and procedural...... risk factors. METHODS AND RESULTS: Observational single-center study of 509 consecutive patients treated with a transcatheter implanted self-expandable aortic valve prosthesis (Medtronic CoreValve). We identified 18 patients diagnosed with TAVI-PVE during a median follow-up period of 1.4 years......%) 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...

  7. 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)

  8. 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...

  9. 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.

  10. 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.

  11. Surge-damping vacuum valve

    Science.gov (United States)

    Bullock, Jack C.; Kelly, Benjamin E.

    1980-01-01

    A valve having a mechanism for damping out flow surges in a vacuum system which utilizes a slotted spring-loaded disk positioned adjacent the valve's vacuum port. Under flow surge conditions, the differential pressure forces the disk into sealing engagement with the vacuum port, thereby restricting the flow path to the slots in the disk damping out the flow surge.

  12. 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.

  13. Combination throttle and shutoff valve

    Science.gov (United States)

    Carriker, J. W.

    1972-01-01

    Combination of translating sleeve throttle valve and conventional poppet valve provides capability of shutting off flow completely by poppet and sleeve control of the rate of flow. Integration of the two concepts can be accomplished without difficulty and in a manner that requires a minimum of development.

  14. 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 ...

  15. Minimally invasive aortic valve replacement

    DEFF Research Database (Denmark)

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

    2009-01-01

    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 valve replacement...... is an excellent operation in selected patients, but its true advantages over conventional aortic valve replacement (other than a smaller scar) await evaluation by means of randomized clinical trial. The "extended mini-aortic valve replacement" operation, on the other hand, is a risky procedure that should...

  16. Injection Beam Loss and Beam Quality Checks for the LHC

    CERN Document Server

    Kain, Verena; Bartmann, Wolfgang; Bracco, Chiara; Drosdal, Lene; Holzer, Eva; Khasbulatov, Denis; Magnin, Nicolas; Meddahi, Malika; Nordt, Annika; Sapinski, Mariusz; Vogt, Mathias

    2010-01-01

    The quality of the injection into the LHC is monitored by a dedicated software system which acquires and analyses the pulse waveforms from the injection kickers, and measures key beam parameters and compares them with the nominal ones. The beam losses at injection are monitored on many critical devices in the injection regions, together with the longitudinal filling pattern and maximum trajectory offset on the first 100 turns. The paper describes the injection quality check system and the results from LHC beam commissioning, in particular the beam losses measured during injection at the various aperture limits. The results are extrapolated to full intensity and the consequences are discussed

  17. Robotic mitral valve surgery.

    Science.gov (United States)

    Kypson, Alan P; Nifong, L Wiley; Chitwood, W Randolph

    2003-12-01

    A renaissance in cardiac surgery has begun. The early clinical experience with computer-enhanced telemanipulation systems outlines the limitations of this approach despite some procedural success. Technologic advancements, such as the use of nitinol U-clips (Coalescent Surgical Inc., Sunnyvale, CA) instead of sutures requiring manual knot tying, have been shown to decrease operative times significantly. It is expected that with further refinements and development of adjunct technologies, the technique of computer-enhanced endoscopic cardiac surgery will evolve and may prove to be beneficial for many patients. Robotic technology has provided benefits to cardiac surgery. With improved optics and instrumentation, incisions are smaller. The ergometric movements and simulated three-dimensional optics project hand-eye coordination for the surgeon. The placement of the wristlike articulations at the end of the instruments moves the pivoting action to the plane of the mitral annulus. This improves dexterity in tight spaces and allows for ambidextrous suture placement. Sutures can be placed more accurately because of tremor filtration and high-resolution video magnification. Furthermore, the robotic system may have potential as an educational tool. In the near future, surgical vision and training systems might be able to model most surgical procedures through immersive technology. Thus, a "flight simulator" concept emerges where surgeons may be able to practice and perform the operation without a patient. Already, effective curricula for training teams in robotic surgery exist. Nevertheless, certain constraints continue to limit the advancement to a totally endoscopic computer-enhanced mitral valve operation. The current size of the instruments, intrathoracic instrument collisions, and extrathoracic "elbow" conflicts still can limit dexterity. When smaller instruments are developed, these restraints may be resolved. Furthermore, a working port incision is still required for

  18. 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.

  19. 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

  20. Valve-related complications after mechanical heart valve implantation.

    Science.gov (United States)

    Misawa, Yoshio

    2015-10-01

    The number of heart valve surgeries is increasing, and 19,164 patients underwent heart valve surgery in Japan in 2011. The early mortality rate has remained stable for more than 10 years. Many patients now survive for many years, with a reported 10-year survival rate of at least 60 %. However, unfavorable complications can occur after valve surgery. Valve-related complications include thromboembolisms, bleeding complications and prosthetic valve endocarditis, followed by structural and nonstructural prosthetic valve dysfunctions. Our review of studies published after 2000 revealed that the rate of all valve-related complications was 0.7-3.5 % per patient-year. Thromboembolisms occur at a rate of approximately 1 % per patient-year, and bleeding complications occur at almost 0.5 % per patient-year. Thromboembolic and hemorrhagic events related to anticoagulant therapy should be considered during life-long follow-up. The occurrence rate of endocarditis reaches 0.5 % per patient-year, with a poor postoperative survival. Structural dysfunctions have been largely overcome, and the nonstructural dysfunction rate is 0.4-1.2 % per patient-year. The nonstructural dysfunctions induced by paravalvular leaks and pannus ingrowth are also issues that need to be resolved.

  1. Patents and heart valve surgery - II: tissue valves.

    Science.gov (United States)

    Cheema, Faisal H; Kossar, Alexander P; Rehman, Atiq; Younas, Fahad; Polvani, Gianluca

    2013-08-01

    Valvular heart disease affects millions of Americans yearly and currently requires surgical intervention to repair or replace the defective valves. Through a close-knit collaboration between physicians, scientists and biomedical engineers, a vast degree of research and development has been aimed towards the optimization of prosthetic heart valves. Although various methods have made fantastic strides in producing durable prostheses, the therapeutic efficacy of prosthetic valves is inherently limited by a dependency upon lifelong anticoagulant regimens for recipients - a difficult challenge for many in clinical setting. Thus, biological tissue valves have been developed to circumvent vascular and immunemediated complications by incorporating biological materials to mimic native valves while still maintaining a necessary level of structural integrity. Over the past decade, a multitude of patents pertaining to the refinement of designs as well as the advancement in methodologies and technologies associated with biological tissue valves have been issued. This review seeks to chronicle and characterize such patents in an effort to track the past, present, and future progress as well as project the trajectory of tissue valves in the years to come. PMID:23919429

  2. Surgical treatment of mitral valve insufficiency by valve repair

    Directory of Open Access Journals (Sweden)

    Murad Henrique

    2002-01-01

    Full Text Available OBJECTIVE: To analyze the short term results of mitral valve repair in a consecutive series of mitral insufficiency patients from different ethiologies. METHODS: A retrospective study was made of 86 patients with mitral insufficiency operated on between May 1992 and May 2001 for mitral valve repair. Mitral insufficiency was severe in 77 patients and moderate in 9. The functional class of the patients was I in 4, II in 48, III in 29 and IV in 5 patients. The etiology was rheumatic in 47 (54.6% cases. RESULTS: Mitral valve repair was performed by only one procedure on the mitral valve in 6 patients, two procedures in 29, and three or more procedures in 51 (59.3% patients. Mitral annuloplasty was performedin 81 patients, with the Braile posterior pericardial ring being the mostcommonly used (87.2%. Hospital mortality was 3.5%. There was improvement in the funcional class in 79 (91.8% patients. Mitral valve function was normal in 80 (93% patients and moderate mitral insufficiency occurred in 6 patients. CONCLUSION: Mitral valve repair can be performed with low mortality (3.5% and high probability of valve function recovery (93%. It should be the procedure of choice in patients with mitral insufficiency.

  3. Patents and heart valve surgery - II: tissue valves.

    Science.gov (United States)

    Cheema, Faisal H; Kossar, Alexander P; Rehman, Atiq; Younas, Fahad; Polvani, Gianluca

    2013-08-01

    Valvular heart disease affects millions of Americans yearly and currently requires surgical intervention to repair or replace the defective valves. Through a close-knit collaboration between physicians, scientists and biomedical engineers, a vast degree of research and development has been aimed towards the optimization of prosthetic heart valves. Although various methods have made fantastic strides in producing durable prostheses, the therapeutic efficacy of prosthetic valves is inherently limited by a dependency upon lifelong anticoagulant regimens for recipients - a difficult challenge for many in clinical setting. Thus, biological tissue valves have been developed to circumvent vascular and immunemediated complications by incorporating biological materials to mimic native valves while still maintaining a necessary level of structural integrity. Over the past decade, a multitude of patents pertaining to the refinement of designs as well as the advancement in methodologies and technologies associated with biological tissue valves have been issued. This review seeks to chronicle and characterize such patents in an effort to track the past, present, and future progress as well as project the trajectory of tissue valves in the years to come.

  4. Three-dimensional echocardiography of the mitral valve: lessons learned.

    Science.gov (United States)

    Maffessanti, Francesco; Mirea, Oana; Tamborini, Gloria; Pepi, Mauro

    2013-07-01

    Three-dimensional echocardiography has markedly improved our understanding of normal and pathologic mitral valve (MV) mechanics. Qualitative and quantitative analysis of three-dimensional (3D) data on the mitral valve could have a clinical impact on diagnosis, patient referral, surgical strategies, annuloplasty ring design and evaluation of the immediate and long-term surgical outcome. This review covers the contribution of 3D echocardiography in the diagnosis of MV disease, its role in selecting and monitoring surgical procedures, and in the assessment of surgical outcomes. Moreover, advantages of this technique versus the standard 2D modality, as well as future applications of advanced analysis techniques, will be reviewed. PMID:23686753

  5. 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.)

  6. 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

  7. 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

  8. Transcatheter Aortic Valve Replacement in Bicuspid Aortic Valve Disease

    DEFF Research Database (Denmark)

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

    2014-01-01

    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...

  9. 14 CFR 91.1093 - Initial and transition training and checking: Check pilots (aircraft), check pilots (simulator).

    Science.gov (United States)

    2010-01-01

    ... OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Fractional Ownership Operations Program Management § 91... preceding 24 months, that person satisfactorily conducts a proficiency or competency check under the..., and emergency procedures to ensure competence to conduct the pilot flight checks required by...

  10. 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...

  11. PWR safety and relief valve test program. Valve selection/juftification report. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1982-12-01

    NUREG 0578 required that full-scale testing be performed on pressurizer safety valves and relief valves representative of those in use or planned for use in PWR plants. To obtain valve performance data for the entire population of PWR plant valves, nine safety valves and ten relief valves were selected as a fully representative set of test valves. Justification that the selected valves represent all PWR plant valves was provided by each safety and relief valve manufacturer. Both the valve selection and justification work was performed as part of the PWR Safety and Relief Valve Test Program conducted by EPRI on behalf of the PWR utilities in response to the recommendations of NUREG 0578 and the requirements of the NRC. Results of the Safety and Relief Valve Selection and Justification effort is documented in this report.

  12. 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

  13. 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.

  14. 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

  15. 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.

  16. 49 CFR 195.260 - Valves: Location.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valves: Location. 195.260 Section 195.260... PIPELINE Construction § 195.260 Valves: Location. A valve must be installed at each of the following... Administrator finds in a particular case that valves are not justified. (f) On each side of a reservoir...

  17. 49 CFR 195.116 - Valves.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valves. 195.116 Section 195.116 Transportation... PIPELINE Design Requirements § 195.116 Valves. Each valve installed in a pipeline system must comply with the following: (a) The valve must be of a sound engineering design. (b) Materials subject to...

  18. 14 CFR 125.133 - Fuel valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Fuel valves. 125.133 Section 125.133....133 Fuel valves. Each fuel valve must— (a) Comply with § 125.155; (b) Have positive stops or suitable... operation or from accelerated flight conditions are not transmitted to the lines connected to the valve....

  19. 49 CFR 192.145 - Valves.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valves. 192.145 Section 192.145 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Design of Pipeline Components § 192.145 Valves. (a) Except for cast iron and plastic valves, each valve must meet the minimum requirements of API...

  20. 14 CFR 125.137 - Oil valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Oil valves. 125.137 Section 125.137....137 Oil valves. (a) Each oil valve must— (1) Comply with § 125.155; (2) Have positive stops or... the valve. (b) The closing of an oil shutoff means must not prevent feathering the propeller,...

  1. 49 CFR 229.109 - Safety valves.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Safety valves. 229.109 Section 229.109....109 Safety valves. Every steam generator shall be equipped with at least two safety valves that have a... allowed working pressure. The safety valves shall be independently connected to the separator and...

  2. 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).

  3. 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.

  4. 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…

  5. 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.

  6. 25 CFR 141.19 - Check cashing.

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Check cashing. 141.19 Section 141.19 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR FINANCIAL ACTIVITIES BUSINESS PRACTICES ON THE NAVAJO, HOPI AND ZUNI RESERVATIONS General Business Practices § 141.19 Check cashing. (a) A reservation...

  7. 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...

  8. 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

  9. SPEED ROLLER STAND MEASUREMENT SYSTEM CHECKING TECHNIQUE

    OpenAIRE

    Zybtsev, Y.; I. Marmut

    2011-01-01

    The study has shown that the accuracy of brakes checking by inertial stands depends upon the applied methods of measurement of braking parameters (stand slowing down, braking distance, brakes triggering time, current speed) as well as the methods of metrological checking of measuring system canals.

  10. 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.

  11. 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)

  12. 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......, to verified fixed point checking. In this paper we demonstrate how quickchecking can be useful for testing a range of static analysis properties with limited effort. We show how to check a range of algebraic lattice properties, to help ensure that an implementation follows the formal specification...... of a lattice. Moreover, we offer a number of generic, type-safe combinators to check transfer functions and operators on lattices, to help ensure that these are, e.g., monotone, strict, or invariant. We substantiate our claims by quickchecking a type analysis for the Lua programming language...

  13. 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.

  14. 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

  15. Safety Testing of Left Ventricular Vent Valves

    OpenAIRE

    Gavin, Caroline; Coblentz, John; Acsell, Jeffrey R.; Shackelford, Anthony G.; Sistino, Joseph J.

    2015-01-01

    Vent vacuum relief valves (VRVs) are used to limit the negative pressure at the ventricular vent catheter tip as well as prevent reversal of blood flow and prevention of air embolism. The purpose of this study was to evaluate the performance of three commercially available ventricular vent valves. The negative pressure at which the vent valve opened was measured at the valve inlet using high-fidelity pressure transducers. Also, the flow rate at which air entrainment occurred due to valve open...

  16. 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...

  17. 14 CFR 91.1089 - Qualifications: Check pilots (aircraft) and check pilots (simulator).

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Qualifications: Check pilots (aircraft) and check pilots (simulator). 91.1089 Section 91.1089 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... RULES Fractional Ownership Operations Program Management § 91.1089 Qualifications: Check...

  18. 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 ...

  19. 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 ...

  20. 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 ...

  1. 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 ...

  2. 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 ...

  3. 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 ...

  4. 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 ...

  5. 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 ...

  6. 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 ...

  7. 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. ...

  8. 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 ...

  9. 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 ...

  10. 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. ...

  11. 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 ...

  12. 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 ...

  13. 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 ...

  14. 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. ...

  15. CONGENITAL QUADRICUSPID AORTIC-VALVE

    NARCIS (Netherlands)

    BROUWER, MHJ; DEGRAAF, JJ; EBELS, T

    1993-01-01

    Two patients with a quadricuspid aortic valve are described, one of them with concomitant juxtaposed coronary orifices facing the right hand facing sinus. The etiology and incidence of this congenital anomaly will be discussed.

  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. The spin-valve transistor

    NARCIS (Netherlands)

    Monsma, Douwe Johannes

    1998-01-01

    High density magnetic recording, magnetic random access memories, displacement and current detection, contactless switching and electronic compass applications all require magnetic field sensors with unprecedented sensitivity. The spin-valve effect (giant magnetoresistance) found in 1988 in magnetic

  18. 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

  19. Enriched MU-Calculi Module Checking

    CERN Document Server

    Ferrante, Alessandro; Parente, Mimmo

    2008-01-01

    The model checking problem for open systems has been intensively studied in the literature, for both finite-state (module checking) and infinite-state (pushdown module checking) systems, with respect to Ctl and Ctl*. In this paper, we further investigate this problem with respect to the Mu-calculus enriched with nominals and graded modalities (hybrid graded Mu-calculus), in both the finite-state and infinite-state settings. Using an automata-theoretic approach, we show that hybrid graded Mu-calculus module checking is solvable in exponential time, while hybrid graded Mu-calculus pushdown module checking is solvable in double-exponential time. These results are also tight since they match the known lower bounds for Ctl. We also investigate the module checking problem with respect to the hybrid graded Mu-calculus enriched with inverse programs (Fully enriched Mu-calculus): by showing a reduction from the domino problem, we show its undecidability. We conclude with a short overview of the model checking problem ...

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

    Directory of Open Access Journals (Sweden)

    K. V. Podmasteryev

    2015-01-01

    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.

  1. 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)

  2. Discussion on The Problems of Lead-acid Battery Projects about Environmental Protection Check and Acceptance Monitoring%铅酸蓄电池项目竣工环保验收监测中有关问题的探讨

    Institute of Scientific and Technical Information of China (English)

    柴敏平; 王东方; 康长安; 曾珍英; 罗勇

    2015-01-01

    根据建设项目竣工环境保护验收规范要求,结合工作实践,从项目的产能核算及验收监测工况的控制、废气处理设施、废水处理设施、环境管理检查及铅排放总量的计算等方面归纳了铅酸蓄电池项目竣工环境保护验收监测工作中应注意的技术问题,并提出存在的问题及建议,为建设项目竣工环保验收监测工作及环保主管部门提供参考。%According to regulation of construction Project comPletion check and accePtance for envi-ronmental Protection and working Practice,this PaPer analyzes some technical issues in lead-acid bat-tery Projects such as caPacity calculation,monitoring condition control,waste gas and waste water Processing facilities,environmental management examination,the calculation method of the total quantity. And then Put forward the existing Problems and suggestions for the construction Project comPletion environmental Protection accePtance monitoring work,so as to offer reference to the com-Petent dePartment of environmental Protection.

  3. 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.)

  4. 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.

  5. 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

  6. 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...

  7. 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...

  8. 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

  9. 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.

  10. 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 ...

  11. LOFT pressurizer safety: relief valve reliability

    Energy Technology Data Exchange (ETDEWEB)

    Brown, E.S.

    1978-01-18

    The LOFT pressurizer self-actuating safety-relief valves are constructed to the present state-of-the-art and should have reliability equivalent to the valves in use on PWR plants in the U.S. There have been no NRC incident reports on valve failures to lift that would challenge the Technical Specification Safety Limit. Fourteen valves have been reported as lifting a few percentage points outside the +-1% Tech. Spec. surveillance tolerance (9 valves tested over and 5 valves tested under specification). There have been no incident reports on failures to reseat. The LOFT surveillance program for assuring reliability is equivalent to nuclear industry practice.

  12. 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

  13. 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

  14. 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...

  15. 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

  16. 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。

  17. 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

  18. 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

  19. 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.

  20. 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)

  1. 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

  2. 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.

  3. Large Scale Magnetostrictive Valve Actuator

    Science.gov (United States)

    Richard, James A.; Holleman, Elizabeth; Eddleman, David

    2008-01-01

    Marshall Space Flight Center's Valves, Actuators and Ducts Design and Development Branch developed a large scale magnetostrictive valve actuator. The potential advantages of this technology are faster, more efficient valve actuators that consume less power and provide precise position control and deliver higher flow rates than conventional solenoid valves. Magnetostrictive materials change dimensions when a magnetic field is applied; this property is referred to as magnetostriction. Magnetostriction is caused by the alignment of the magnetic domains in the material s crystalline structure and the applied magnetic field lines. Typically, the material changes shape by elongating in the axial direction and constricting in the radial direction, resulting in no net change in volume. All hardware and testing is complete. This paper will discuss: the potential applications of the technology; overview of the as built actuator design; discuss problems that were uncovered during the development testing; review test data and evaluate weaknesses of the design; and discuss areas for improvement for future work. This actuator holds promises of a low power, high load, proportionally controlled actuator for valves requiring 440 to 1500 newtons load.

  4. 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...

  5. 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.

  6. 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.

  7. Percutaneous heart valves; past, present and future.

    Science.gov (United States)

    Rozeik, M M; Wheatley, D J; Gourlay, T

    2014-09-01

    Percutaneous heart valves provide a promising future for patients refused surgery on the grounds of significant technical challenges or high risk for complications. Since the first human intervention more than 10 years ago, over 50 different types of valves have been developed. The CoreValve and Edwards SAPIEN valves have both experienced clinical trials and the latter has gained FDA approval for implantation in patients considered inoperable. Current complications, such as major vascular bleeding and stroke, prevent these valves from being commonly deployed in patients considered operable in conventional surgery. This review focuses on the past and present achievements of these valves and highlights the design considerations required to progress development further. It is envisaged that, with continued improvement in valve design and with increased clinical and engineering experience, percutaneous heart valve replacement may one day be a viable option for lower-risk operable patients.

  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. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 49 CFR 179.400-19 - Valves and gages.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Valves and gages. 179.400-19 Section 179.400-19...-19 Valves and gages. (a) Valves. Manually operated shut-off valves and control valves must be... liquid flow rates. All valves must be made from approved materials compatible with the lading and...

  15. 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

  16. Transcatheter valve-in-valve implantation due to severe aortic regurgitation in a degenerated aortic homograft

    DEFF Research Database (Denmark)

    Olsen, Lene Kjaer; Engstrøm, Thomas; Søndergaard, Lars

    2009-01-01

    a successful valve-in-valve implantation of a CoreValve aortic valve prosthesis through the right subclavian artery in a case of severe aortic regurgitation within a degenerated aortic homograft. The case exemplifies the possibilities of expanding the indications for TAVI, as well as other vascular access...

  17. The nordic aortic valve intervention (NOTION) trial comparing transcatheter versus surgical valve implantation

    DEFF Research Database (Denmark)

    Thyregod, Hans Gustav; Søndergaard, Lars; Ihlemann, Nikolaj;

    2013-01-01

    Degenerative aortic valve (AV) stenosis is the most prevalent heart valve disease in the western world. Surgical aortic valve replacement (SAVR) has until recently been the standard of treatment for patients with severe AV stenosis. Whether transcatheter aortic valve implantation (TAVI) can...

  18. Pregnancy-induced remodeling of heart valves.

    Science.gov (United States)

    Pierlot, Caitlin M; Moeller, Andrew D; Lee, J Michael; Wells, Sarah M

    2015-11-01

    Recent studies have demonstrated remodeling of aortic and mitral valves leaflets under the volume loading and cardiac expansion of pregnancy. Those valves' leaflets enlarge with altered collagen fiber architecture, content, and cross-linking and biphasic changes (decreases, then increases) in extensibility during gestation. This study extends our analyses to right-sided valves, with additional compositional measurements for all valves. Valve leaflets were harvested from nonpregnant heifers and pregnant cows. Leaflet structure was characterized by leaflet dimensions, and ECM composition was determined using standard biochemical assays. Histological studies assessed changes in cellular and ECM components. Leaflet mechanical properties were assessed using equibiaxial mechanical testing. Collagen thermal stability and cross-linking were assessed using denaturation and hydrothermal isometric tension tests. Pulmonary and tricuspid leaflet areas increased during pregnancy by 35 and 55%, respectively. Leaflet thickness increased by 20% only in the pulmonary valve and largely in the fibrosa (30% thickening). Collagen crimp length was reduced in both the tricuspid (61%) and pulmonary (42%) valves, with loss of crimped area in the pulmonary valve. Thermomechanics showed decreased collagen thermal stability with surprisingly maintained cross-link maturity. The pulmonary leaflet exhibited the biphasic change in extensibility seen in left side valves, whereas the tricuspid leaflet mechanics remained largely unchanged throughout pregnancy. The tricuspid valve exhibits a remodeling response during pregnancy that is significantly diminished from the other three valves. All valves of the heart remodel in pregnancy in a manner distinct from cardiac pathology, with much similarity valve to valve, but with interesting valve-specific responses in the aortic and tricuspid valves.

  19. Promising results after percutaneous mitral valve repair

    DEFF Research Database (Denmark)

    Ihlemann, Nikolaj; Franzen, Olaf; Jørgensen, Erik;

    2011-01-01

    Mitral valve regurgitation (MR) is the secondmost frequent valve disease in Europe. Untreated MR causes considerable morbidity and mortality. In the elderly, as many as half of these patients are denied surgery because of an estimated high surgical risk. Percutaneous mitral valve repair with the ...... with the MitraClip system resembles the Alfieristitch where a clip is used to connect the tip of the mitral valve leaflets....

  20. Promising results after percutaneous mitral valve repair

    DEFF Research Database (Denmark)

    Ihlemann, Nikolaj; Franzen, Olaf; Jørgensen, Erik;

    2011-01-01

    Mitral valve regurgitation (MR) is the secondmost frequent valve disease in Europe. Untreated MR causes considerable morbidity and mortality. In the elderly, as many as half of these patients are denied surgery because of an estimated high surgical risk. Percutaneous mitral valve repair...... with the MitraClip system resembles the Alfieristitch where a clip is used to connect the tip of the mitral valve leaflets....

  1. 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....

  2. 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

  3. 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.

  4. Pressure relief valve/safety relief valve testing

    Energy Technology Data Exchange (ETDEWEB)

    Murray, W.A.; Hamm, E.R.; Barber, J.R.

    1994-02-01

    Pressure vessels and piping systems are protected form overpressurization by pressure relief valves. These safety features are required to be tested-inspected on some periodic basis and, in most cases witnessed by a third party inspector. As a result nonconformances found by third parties Westinghouse Hanford Company initiated a task team to develop a pressure safety program. This paper reveals their findings.

  5. Whitey SCHE Gauge and Root Valves

    Energy Technology Data Exchange (ETDEWEB)

    MISKA, C.R.

    2000-09-11

    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 SCHa System between the helium bottle supply manifolds and safety class helium pressure instrumentation, and in lower pressure SCHa supply line.

  6. Whitey SCHE Gauge and Root Valves

    Energy Technology Data Exchange (ETDEWEB)

    MISKA, C.R.

    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 SCHe System between the helium bottle supply manifolds and safety class helium pressure instrumentation, and in lower pressure SCHe supply line.

  7. Miniature piezo electric vacuum inlet valve

    Science.gov (United States)

    Keville, Robert F.; Dietrich, Daniel D.

    1998-03-24

    A miniature piezo electric vacuum inlet valve having a fast pulse rate and is battery operated with variable flow capability. The low power (piezo electric valves which require preloading of the crystal drive mechanism and 120 Vac, thus the valve of the present invention is smaller by a factor of three.

  8. 14 CFR 27.995 - Fuel valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel valves. 27.995 Section 27.995... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Fuel System Components § 27.995 Fuel valves. (a) There must be a positive, quick-acting valve to shut off fuel to each engine individually. (b) The control...

  9. 14 CFR 29.995 - Fuel valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel valves. 29.995 Section 29.995... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System Components § 29.995 Fuel valves. In addition to meeting the requirements of § 29.1189, each fuel valve must— (a) (b) Be supported so that no...

  10. 14 CFR 25.995 - Fuel valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel valves. 25.995 Section 25.995... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System Components § 25.995 Fuel valves. In addition to the requirements of § 25.1189 for shutoff means, each fuel valve must— (a) (b) Be supported...

  11. 14 CFR 29.1025 - Oil valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Oil valves. 29.1025 Section 29.1025... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Oil System § 29.1025 Oil valves. (a) Each oil shutoff.... (c) Each oil valve must have positive stops or suitable index provisions in the “on” and...

  12. 14 CFR 25.1025 - Oil valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Oil valves. 25.1025 Section 25.1025... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Oil System § 25.1025 Oil valves. (a) Each oil shutoff... feathering. (c) Each oil valve must have positive stops or suitable index provisions in the “on” and...

  13. 49 CFR 195.258 - Valves: General.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valves: General. 195.258 Section 195.258... PIPELINE Construction § 195.258 Valves: General. (a) Each valve must be installed in a location that is accessible to authorized employees and that is protected from damage or tampering. (b) Each submerged...

  14. 14 CFR 121.239 - Oil valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Oil valves. 121.239 Section 121.239..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.239 Oil valves. (a) Each oil valve must— (1) Comply with § 121.257; (2) Have positive stops or suitable index provisions in the...

  15. 14 CFR 121.235 - Fuel valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Fuel valves. 121.235 Section 121.235..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.235 Fuel valves. Each fuel valve must— (a) Comply with § 121.257; (b) Have positive stops or suitable index provisions in the...

  16. 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.…

  17. Staphylococcus saprophyticus causing native valve endocarditis.

    Science.gov (United States)

    Garduño, Eugenio; Márquez, Irene; Beteta, Alicia; Said, Ibrahim; Blanco, Javier; Pineda, Tomás

    2005-01-01

    Coagulase negative staphylococci are a rare cause of native valve endocarditis. Staphylococcus saprophyticus is a coagulase-negative Staphylococcus infrequently reported as a human pathogen, and most of the cases reported are urinary tract infections. We describe a case of native valve endocarditis attributed to this organism. The patient needed valve replacement due to heart failure.

  18. 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.

  19. 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.

  20. 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。

  1. 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.

  2. 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.

  3. 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…

  4. 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…

  5. Check In / Check Out. The Public Space as an Internet of Things

    NARCIS (Netherlands)

    van t Hof, C.C.G.; van Est, R.; Daemen, F.

    2011-01-01

    Mobile phones, public transport smart cards, security cameras and GPS systems in our car - we are surrounded by digital devices. They track us, guide us, help us, and control us. The book Check In / Check Out. The Public Space as an Internet of Things shows us how our digital and physical worlds are

  6. 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...

  7. 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...

  8. A Method for Model Checking Feature Interactions

    DEFF Research Database (Denmark)

    Pedersen, Thomas; Le Guilly, Thibaut; Ravn, Anders Peter;

    2015-01-01

    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 ...... the definitions with models to ensure that all interactions are captured. The method is illustrated on a home automation example with model checking as analysis tool. In particular, the modelling formalism is timed automata and the analysis uses UPPAAL to find interactions....

  9. 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. ...

  10. 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.

  11. Microprocessor-Based Valved Controller

    Science.gov (United States)

    Norman, Arnold M., Jr.

    1987-01-01

    New controller simpler, more precise, and lighter than predecessors. Mass-flow controller compensates for changing supply pressure and temperature such as occurs when gas-supply tank becomes depleted. By periodically updating calculation of mass-flow rate, controller determines correct new position for valve and keeps mass-flow rate nearly constant.

  12. 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 ...

  13. 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.

  14. 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.

  15. Check list of European Hymenomycetous Heterobasidiae

    NARCIS (Netherlands)

    Donk, M.A.

    1966-01-01

    With this check list an attempt is made to account for the recorded European species of those Basidiomycetes that Patouillard called the “Hétérobasidies”, excluding, however, the Uredinales and Ustilaginales. Therefore, it covers the Septobasidiales, Tremellales (comprising the Auriculariineae and T

  16. Model Checking as Static Analysis: Revisited

    DEFF Research Database (Denmark)

    Zhang, Fuyuan; Nielson, Flemming; Nielson, Hanne Riis

    2012-01-01

    We show that the model checking problem of the μ-calculus can be viewed as an instance of static analysis. We propose Succinct Fixed Point Logic (SFP) within our logical approach to static analysis as an extension of Alternation-free Least Fixed Logic (ALFP). We generalize the notion...

  17. Incremental Integrity Checking: Limitations and Possibilities

    DEFF Research Database (Denmark)

    Christiansen, Henning; Martinenghi, Davide

    2005-01-01

    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...

  18. Efficient CSL Model Checking Using Stratification

    DEFF Research Database (Denmark)

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

    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 expone...

  19. Explicit State Model Checking for Graph Grammars

    NARCIS (Netherlands)

    Rensink, A.; De Nicola, R.; Degano, P.; Meseguer, J.

    2008-01-01

    In this paper we present the philosophy behind the GROOVE project, in which graph transformation is used as a modelling formalism on top of which a model checking approach to software verification is being built. We describe the basic formalism, the current state of the project, and (current and fut

  20. 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.

  1. 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...

  2. 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...

  3. 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

  4. 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.

  5. 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

  6. 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

  7. 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 replacement....... We report the first case of surgical valve replacement in a patient with a dysfunctional transcatheter-implanted aortic valve prosthesis 4 months after implantation....

  8. 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....

  9. 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...

  10. 14 CFR 121.315 - Cockpit check procedure.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Cockpit check procedure. 121.315 Section... Cockpit check procedure. (a) Each certificate holder shall provide an approved cockpit check procedure for... for items to be checked. (c) The approved procedures must be readily usable in the cockpit of...

  11. Outlet strut fracture of Björk-Shiley convexo concave heart valves: the UK cohort study

    Science.gov (United States)

    Omar, R; Morton, L; Halliday, D; Danns, E; Beirne, M; Blot, W; Taylor, K

    2001-01-01

    OBJECTIVE—To investigate the risk of outlet strut fracture (OSF) in Björk-Shiley convexo concave (BSCC) valves in relation to patients' clinical and valve characteristics.
DESIGN—A cohort of 2977 patients with 3325 valves with a follow up of 18 years.
SETTING—38 cardiac implantation centres in the UK.
RESULTS—56 OSF events were reported with 43 occurring in mitral and 13 in aortic valves. The overall OSF rate was 0.17%/year. No dominant clinical factor of risk was found, but multiple regression analysis identified age, body surface area, valve size, shop order fracture rate, and manufacturing period as risk factors for OSF. A 4% (95% confidence interval (CI) 2% to 6%) decrease in the risk of OSF was observed for each advancing year of age and a fivefold (95% CI 2 to 13) increase in risk for a 0.5 m2 increase in body surface area. The association between the risk of OSF and valve size was not constant over time. Excess risks among 31 mm and 33 mm sizes (mainly mitral valves) decreased over time while that for 23 mm (almost all aortic valves) increased. The risk of OSF increased by 40% (95% CI 20% to 50%) for a unit increase in the fracture rate of other valves in the same batch. For valves manufactured during 1981 to 1984 the risk of OSF was 4 (95% CI 2 to 12) times greater than for valves manufactured before 1981.
CONCLUSIONS—The OSF rates for 60° BSCC valves observed in the UK are the highest among all monitored populations. The changing patterns of mitral and aortic valve OSF rates over time observed in this study have not been identified previously and highlight the need for continued monitoring of patients with the BSCC valve.


Keywords: cohort studies; heart valves; outlet strut fracture PMID:11410563

  12. 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.

  13. [Minimally invasive cardiac surgery for aortic valve disease].

    Science.gov (United States)

    Fujimura, Y; Katoh, T; Hamano, K; Gohra, H; Tsuboi, H; Esato, K

    1998-12-01

    Recent surgical advances leading to good operative results have contributed to the trend to useminimally invasive approaches, even in cardiac surgery. Smaller incisions are clearly more cosmetically acceptable to patients. When using a minimally invasive approach, it is most important to maintain surgical quality without jeopardizing patients. A good operative visual field leads to good surgical results. In the parasternal approach, we use a retractor to harvest an internal thoracic artery in coronary artery bypass surgery. Retracting the sternum upward allows for a good surgical view and permits the use of an arch cannula rather than femoral cannulation. When reoperating for aortic valve repair, the j-sternotomy approach requires less adhesiolysis compared with the traditional full sternotomy. No special technique is necessary to perform aortic valve surgery using the j-sternotomy approach. However, meticulous attention must be paid to avoiding left ventricular air embolisms to prevent postoperative stroke or neurocognitive deficits, especially when utilizing a minimally invasive approach. Transesophageal echo is useful not only for monitoring cardiac function but also for monitoring the persence of air in the left ventricle and atrium. This paper compare as the degree of invasion of minimally invasive cardiac surgery and the traditional full sternotomy. No differences were found in the occurrence of systemic inflammatory response syndrome between patients undergoing minimally invasive cardiac surgery and the traditional technique. Therefore it is concluded that minimally invasive surgery for patients with aortic valve disease may become the standard approach in the near future.

  14. 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

  15. The Dynamic Checking of Complex Real Time System

    Institute of Scientific and Technical Information of China (English)

    YU Chao; HUANG Benwen; WU Guoqing

    2006-01-01

    The paper presents an dynamic execution model of complex real-time software based on requirement description model RTRSM, and then propose a checking method based on configuration covering and its corresponding algorithm. This checking method can check the execution situations between parallel elements in a dynamic execution step of real-time software systems. It also can check all the states and transitions which assure the completeness of checking. In the end, related theorem is proofed.

  16. 49 CFR Appendix B to Part 180 - Acceptable Internal Self-closing Stop Valve Leakage Tests for Cargo Tanks Transporting Liquefied...

    Science.gov (United States)

    2010-10-01

    ... leakage testing, leakage is defined as any leakage through the internal self-closing valve or to the... flow is established, the operator closes the internal self-closing stop valve and monitors the meter... meter as a flow measurement indicator. The test is initiated by starting the delivery process...

  17. 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.

  18. 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.

  19. Traumatic Mitral Valve and Pericardial Injury

    Directory of Open Access Journals (Sweden)

    Nissar Shaikh

    2013-01-01

    Full Text Available Cardiac injury after blunt trauma is common but underreported. Common cardiac trauma after the blunt chest injury (BCI is cardiac contusion; it is very rare to have cardiac valve injury. The mitral valve injury during chest trauma occurs when extreme pressure is applied at early systole during the isovolumic contraction between the closure of the mitral valve and the opening of the aortic valve. Traumatic mitral valve injury can involve valve leaflet, chordae tendineae, or papillary muscles. For the diagnosis of mitral valve injury, a high index of suspicion is required, as in polytrauma patients, other obvious severe injuries will divert the attention of the treating physician. Clinical picture of patients with mitral valve injury may vary from none to cardiogenic shock. The echocardiogram is the main diagnostic modality of mitral valve injuries. Patient’s clinical condition will dictate the timing and type of surgery or medical therapy. We report a case of mitral valve and pericardial injury in a polytrauma patient, successfully treated in our intensive care unit.

  20. [Minimally Invasive Mitral Valve Plasty;My Technique].

    Science.gov (United States)

    Ito, Toshiaki

    2016-07-01

    We perform minimally invasive mitral valve plasty under totally endoscopic view. Skin incisions are composed of a 3 to 5 cm of main wound along the right 4th intercostal space, 1 trocar port in the 3rd intercostal space, and a camera port in the 5th intercostal space. Matal rib spreader is not used. A 3-dimensional endoscope was recently introduced. Forceps controlled by the left hand are inserted through the independent trocar port in the 3rd intercostal space. Left atrial retractor, aortic clamp, and all the cannulae are inserted through the main incision. Cardio-pulmonary bypass is established through the right femoral artery and vein cannulation. No additional venous cannula through the right jugular vein is used. Posterior leaflet lesions are repaired by resection and suture technique. Anterior leaflet prolapse is repaired mainly using the loop technique. Bleeding from the chest wall is meticulously checked before closing the chest.

  1. 32 CFR Attachment A to Subpart B... - Standard A-National Agency Check With Local Agency Checks and Credit Check (NACLC)

    Science.gov (United States)

    2010-07-01

    ... Access Programs by sect. 4.4 of Executive Order 12958) (60 FR 19825, 3 CFR 1995 Comp., p. 333); (2) “L... Agency Checks and Credit Check (NACLC) A Attachment A to Subpart B of Part 147 National Defense..., Subpt. B, Att. A Attachment A to Subpart B of Part 147—Standard A—National Agency Check With...

  2. 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.

  3. 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

  4. [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

  5. [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.

  6. Maintenance Check-ups Following Treatment for Cannabis Dependence.

    Science.gov (United States)

    Walker, Denise D; Stephens, Robert S; Towe, Sheri; Banes, Kelsey; Roffman, Roger

    2015-09-01

    Substance use disorders, including cannabis use disorders and associated negative consequences, are best considered chronic and in need of continuing care. In contrast, most treatment efficacy studies evaluate a fixed number of intervention sessions at a single point in time. The present study evaluated the efficacy of posttreatment maintenance check-ups (MCUs) in maintaining and improving outcomes following nine sessions of motivational enhancement treatment/cognitive behavioral treatment (MET/CBT). Adults dependent on cannabis (n=74) were randomly assigned to the MCU or a no check-up (NCU) condition and followed up at 3- and 9-months. MCU sessions occurred 1 and 4months following the completion of the base treatment. Additional MET/CBT sessions were available to participants throughout the follow-up period. The MCUs specifically encouraged treatment re-entry for those showing ongoing signs of disorder. Participants in the MCU condition reported significantly greater abstinent rates at both follow-ups and were using on fewer days at the 3-month but not the 9-month follow-up. Contrary to hypotheses, MCU participants did not attend more additional treatment and differences in rates of cannabis use emerged prior to the first MCU session. Future research with longer follow-up periods and longer monitoring of outcomes is needed to fully evaluate the utility of MCUs or other forms of continuing care.

  7. 49 CFR 179.500-11 - Loading and unloading valves.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Loading and unloading valves. 179.500-11 Section...-113 and 107A) § 179.500-11 Loading and unloading valves. (a) Loading and unloading valve or valves shall be mounted on the cover or threaded into the marked end of tank. These valves shall be of...

  8. Miniature electrically operated diaphragm valve

    Energy Technology Data Exchange (ETDEWEB)

    Adkins, Douglas R. (Albuquerque, NM); Spletzer, Barry L. (Albuquerque, NM); Wong, Chungnin C. (Albuquerque, NM); Frye-Mason, Gregory C. (Cedar Crest, NM); Fischer, Gary J. (Albuquerque, NM); Hesketh, Peter J. (Atlanta, GA)

    2001-01-01

    The present invention provides a miniature electrically operated valve that can stand off significant pressures, that can be inexpensively produced, and that can be made to operate without continuous electrical power. A valve according to the present invention comprises a housing and a beam mounted with the housing. A diaphragm mounted with the housing forms a sealed fluid volume. An electromagnetic energy source, such as an electromagnetic coil, mounts with the housing and when energized urges the beam in one direction. The beam can be urged in the opposing direction by passive means or by reversing the polarity of the electromagnetic energy source or by a second electromagnetic energy source. Two fluid ports mount with the housing. A first fluid port mounts so that, as the beam is urged in one direction or the opposite, the beam urges the diaphragm to move between engaging and substantially sealing the fluid port and disengaging and not substantially sealing the fluid port. A seat can be mounted with the diaphragm to aid in sealing the fluid port. Latching mechanisms such as permanent magnets can be mounted so that the valve remains in the open or closed positions without continuous electrical power input. Fluid can flow through the housing between the two fluid ports when the diaphragm does not seal the first fluid port, but can be prevented from flowing by urging the beam so that the diaphragm seals the first fluid port. Various embodiments accommodate various latching mechanisms, electromagnetic energy sources, number of fluid ports, and diaphragm design considerations.

  9. 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...

  10. Advanced techniques for efficient data integrity checking

    DEFF Research Database (Denmark)

    Martinenghi, Davide

    ” that may go beyond predefined constraints such as primary keys and foreign keys. General integrity constraints are, however, far from being widely available in commercial systems; in fact, their usage is commonly not encouraged, since the database management system would not be able to provide...... modifications in such programs. In this respect, database management systems need to be extended with means to verify, automatically and incrementally, that no violation of integrity is introduced by database updates. For this purpose we develop a procedure aimed at producing incremental checks whose...... be found in which optimality can indeed a lways be guaranteed. Furthermore, non-optimal simplification may imply a slight loss of efficiency, but still is a great improvement with respect to non-incremental checking. Finally, we extend the applicability of simplification to a number of different contexts...

  11. Transfemoral Valve-in-Valve Transcatheter Aortic Valve Implantation (TAVI) in a Patient With Previous Endovascular Aortic Repair (EVAR).

    Science.gov (United States)

    Ruparelia, Neil; Panoulas, Vasileios F; Frame, Angela; Nathan, Anthony W; Ariff, Ben; Jaffer, Usman; Sutaria, Nilesh; Chukwuemeka, Andrew; Mikhail, Ghada W; Malik, Iqbal S

    2016-07-01

    A 90-year-old man presented with increasing exertional breathlessness. He had previous implantation of a Perimount bioprosthetic aortic valve (Edwards Lifesciences) and coronary artery bypass graft surgery. Due to severe transvalvular bioprosthetic regurgitation with preserved left ventricular dimensions and ejection fraction, the heart team decided on valve-in- valve transcatheter aortic valve implantation via the transfemoral route in view of the patient's prohibitively high surgical and anesthetic risk. The patient had an uncomplicated recovery and was symptomatically much improved at 3-month follow-up. PMID:27342209

  12. Type checking with open type functions

    DEFF Research Database (Denmark)

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

    2008-01-01

    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; an......; and we give a novel, decidable, sound, and complete algorithm to solve it, together with some practically-important variants. Our system is implemented in GHC, and is already in active use....

  13. 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

  14. 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...

  15. 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.

  16. 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.

  17. Maximizing prosthetic valve size with the Top Hat supra-annular aortic valve

    DEFF Research Database (Denmark)

    Aagaard, Jan; Geha, Alexander S.

    2007-01-01

    BACKGROUND AND AIM OF THE STUDY: The CarboMedics Top Hat supra-annular aortic valve allows a one-size (and often two-size) increase over the standard intra-annular valve. This advantage should minimize the risk of patient-prosthesis mismatch, where the effective prosthetic valve orifice area...... is less than that of a normal valve. It is suggested that the ability to implant Top Hat valves having greater size, relative to standard intra-annular valves, may currently be under-utilized. Further, there has been some concern that Top Hat implantation can cause obstruction of the coronary ostia....... This study evaluates the authors' clinical experience with Top Hat supra-annular aortic valve size selection, and the technical aspects of implantation. METHODS: Between January 1999 and October 2005, a total of 251 consecutive patients underwent 252 aortic valve replacements with Top Hat supra...

  18. Imaging of Cardiac Valves by Computed Tomography

    Directory of Open Access Journals (Sweden)

    Gudrun Feuchtner

    2013-01-01

    Full Text Available This paper describes “how to” examine cardiac valves with computed tomography, the normal, diseased valves, and prosthetic valves. A review of current scientific literature is provided. Firstly, technical basics, “how to” perform and optimize a multislice CT scan and “how to” interpret valves on CT images are outlined. Then, diagnostic imaging of the entire spectrum of specific valvular disease by CT, including prosthetic heart valves, is highlighted. The last part gives a guide “how to” use CT for planning of transcatheter aortic valve implantation (TAVI, an emerging effective treatment option for patients with severe aortic stenosis. A special focus is placed on clinical applications of cardiac CT in the context of valvular disease.

  19. 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

  20. 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

  1. 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...

  2. 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...

  3. AN ACTIVE VALVE WITH A CLAMPED MEMBRANE

    DEFF Research Database (Denmark)

    2009-01-01

    An active valve for use e.g. in fluidic microsystems is provided, wherein the active valve comprises a membrane having at least one flow gate, arranged between a first and a second substantially rigid element. Adjusting means provides an adjustment of the clamping force on membrane arranged between...... the first and second substantially rigid element. Hereby the flow rate through the active valve can be continuously and precisely controlled....

  4. Low-Pressure-Drop Shutoff Valve

    Science.gov (United States)

    Thornborrow, John

    1994-01-01

    Flapper valve remains open under normal flow conditions but closes upon sudden increases to high rate of flow and remains closed until reset. Valve is fluid/mechanical analog of electrical fuse or circuit breaker. Low-pressure-drop shutoff valve contains flapper machined from cylindrical surface. During normal flow conditions, flapper presents small cross section to flow. (Useful in stopping loss of fluid through leaks in cooling systems.)

  5. 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...

  6. STUDY ON FLUID THICKNESS BETWEEN POPPET AND VALVE GUIDE IN CONTROL VALVE OF INJECTOR

    Institute of Scientific and Technical Information of China (English)

    Zhang Jianming; Zhang Weigang; Wang Yawei

    2004-01-01

    The physical model of -20 diesel oil and force model of injector control valve of common rail system is built. The changes of the fluid thickness are investigated on the base of the results of CFD and experiments for control valve of injector. The results indicate that a fluid thickness of 0.02~0.03 mm between the poppet and valve guide is sufficient to dampen any excessive control valve poppet bouncing.

  7. Double-reed exhaust valve engine

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Charles L.

    2015-06-30

    An engine based on a reciprocating piston engine that extracts work from pressurized working fluid. The engine includes a double reed outlet valve for controlling the flow of low-pressure working fluid out of the engine. The double reed provides a stronger force resisting closure of the outlet valve than the force tending to open the outlet valve. The double reed valve enables engine operation at relatively higher torque and lower efficiency at low speed, with lower torque, but higher efficiency at high speed.

  8. The future of transcatheter mitral valve interventions

    DEFF Research Database (Denmark)

    Maisano, Francesco; Alfieri, Ottavio; Banai, Shmuel;

    2015-01-01

    the transcatheter intervention armamentarium. Recently, the feasibility of transcatheter mitral valve implantation in native non-calcified valves has been reported in very high-risk patients. Acknowledging the lack of scientific evidence to date, it is difficult to predict what the ultimate future role...... of transcatheter mitral valve interventions will be. The purpose of the present report is to review the current state-of-the-art of mitral valve intervention, and to identify the potential future scenarios, which might benefit most from the transcatheter repair and replacement devices under development....

  9. Additively Manufactured Main Fuel Valve Housing

    Science.gov (United States)

    Eddleman, David; Richard, Jim

    2015-01-01

    Selective Laser Melting (SLM) was utilized to fabricate a liquid hydrogen valve housing typical of those found in rocket engines and main propulsion systems. The SLM process allowed for a valve geometry that would be difficult, if not impossible to fabricate by traditional means. Several valve bodies were built by different SLM suppliers and assembled with valve internals. The assemblies were then tested with liquid nitrogen and operated as desired. One unit was also burst tested and sectioned for materials analysis. The design, test results, and planned testing are presented herein.

  10. Biocompatibility of a novel tissue connector for fixation of tracheostoma valves and shunt valves

    NARCIS (Netherlands)

    Geertsema, AA; Schutte, HK; van Leeuwen, MBM; Rakhorst, G; Schakenraad, JM; van Luyn, MJA; Verkerke, GJ

    1999-01-01

    Rehabilitation after laryngectomy often includes the use of a shunt valve and a tracheostoma valve to restore voice. To improve the fixation method of these valves, a new tissue connector has been developed, basically consisting of a ring that will be integrated into surrounding tracheal soft tissue

  11. Matching flow characteristics of standard shutoff valves eliminates need for custom fabricated valves

    Science.gov (United States)

    Bevan, A. F.

    1966-01-01

    Standard high pressure valves are used in low pressure fluid system testing when a substantial system pressure increase is required. The flow-vs-valve stroke is matched with that of the valves being replaced. Some correction to the plug contour may be necessary.

  12. A KINEMATIC ANALYSIS OF THE VALVE TIMING MECHANISM WITH THREE ELEMENTS AND CONTINUOUS VALVE LIFT

    Directory of Open Access Journals (Sweden)

    Stelian MIHALCEA

    2010-06-01

    Full Text Available An innovating solution for throttle-free load control for spark-ignition engines is variable valve timing system. In this paper is presented a kinematic analysis, using the analytic method, of the valve timing mechanism with three elements and continuous valve lift variation. It is also presented the numerical algorithm for the mechanism’s motion.

  13. New-Onset Atrial Fibrillation After Surgical Aortic Valve Replacement and Transcatheter Aortic Valve Implantation

    DEFF Research Database (Denmark)

    Jørgensen, Troels Højsgaard; Thygesen, Julie Bjerre; Thyregod, Hans Gustav;

    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...

  14. Repositioning of an Intraventricular Dislocated Aortic Valve during Transcatheter Aortic Valve Implantation

    NARCIS (Netherlands)

    Natour, Ehsan; Douglas, Yvonne L.; Jainandunsing, Jayant S.; Schurer, Remco A. J.; van der Werf, Hendrik W.; van den Heuvel, Ad F. M.

    2014-01-01

    The case is presented of a 75-year-old man referred for transcatheter aortic valve implantation. During the procedure the prosthetic aortic valve became dislocated into the left ventricle shortly after expansion. The subsequent steps taken to reposition the valve using only materials at hand are des

  15. New-onset atrial fibrillation after surgical aortic valve replacement and transcatheter aortic valve implantation

    DEFF Research Database (Denmark)

    Jørgensen, Troels Højsgaard; Thygesen, Julie Bjerre; Thyregod, Hans Gustav;

    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...

  16. Transapical JenaValve in a patient with mechanical mitral valve prosthesis.

    LENUS (Irish Health Repository)

    O' Sullivan, Katie E

    2014-01-29

    We report the first case of transcatheter aortic valve replacement implantation using JenaValve™ in a patient with mechanical mitral valve prosthesis. We believe that the design features of this valve may be particularly suited for use in this setting. © 2014 Wiley Periodicals, Inc.

  17. Growth in boys and posterior urethral valves. Primary valve resection vs upper tract diversion.

    Science.gov (United States)

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

    1980-06-01

    Seventy-four patients with posterior urethral valves were evaluated for long-term growth potential and renal function. In those boy diagnosed and treated within the first year of life, initial treatment by temporary supravesical diversion (prior to valve resection) was associated with better growth potential and renal function than was treatment by primary valve resection alone. PMID:7404868

  18. A Study on the Evaluation of Valve Leak Rates Using Acoustic Emission Technique

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Guk; Lee, Jun Shin; Lee, Sun Ki; Shon, Seok Man; Lee, Wook Ryun; Kim, Tae Ryong [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Lim, Yong Jae; Choo, Kee Young [Hana Evertech Co., Seongnam (Korea, Republic of)

    2005-07-01

    The objective of this study is to estimate the feasibility of acoustic emission method for the internal leak from the valves. In this study, two types of valve(a 3 1/2 inch glove valve for 600 psi steam and a 4 inch ball valve water ) leak tests using three different leak path and numerous leak rates were performed in order to analyze acoustic emission properties when leaks arise in valve seat. As a result of leak test for specimens simulated valve seat, we conformed that leak sound amplitude increased in proportion to the increase of leak rate, and leak rates were plotted versus peak acoustic amplitudes recorded within those two narrow frequency bands on each spectral plot. The resulting plots of leak rate versus peak acoustic amplitude were the primary basis for determining the feasibility of quantifying leak acoustically. The large amount of data collected also allowed a grief investigation of the effects of different leak paths, leakage rates, pressure differentials and transducers on the acoustic amplitude spectra. From the experimental results, it was suggested that the acoustic emission method for monitoring of leak was feasible.

  19. Hydraulic engine valve actuation system including independent feedback control

    Science.gov (United States)

    Marriott, Craig D

    2013-06-04

    A hydraulic valve actuation assembly may include a housing, a piston, a supply control valve, a closing control valve, and an opening control valve. The housing may define a first fluid chamber, a second fluid chamber, and a third fluid chamber. The piston may be axially secured to an engine valve and located within the first, second and third fluid chambers. The supply control valve may control a hydraulic fluid supply to the piston. The closing control valve may be located between the supply control valve and the second fluid chamber and may control fluid flow from the second fluid chamber to the supply control valve. The opening control valve may be located between the supply control valve and the second fluid chamber and may control fluid flow from the supply control valve to the second fluid chamber.

  20. Globe stability during simulated vitrectomy with valved and non-valved trocar cannulas

    Directory of Open Access Journals (Sweden)

    Abulon DJ

    2015-09-01

    Full Text Available Dina Joy Abulon,1 Martin Charles,2 Daniel E Charles21Global Medical Affairs, Alcon Laboratories, Inc., Lake Forest, CA, USA; 2Centro Oftalmológico Dr Charles, Buenos Aires, ArgentinaPurpose: To compare the effects of valved and non-valved cannulas on intraocular pressure (IOP, fluid leakage, and vitreous incarceration during simulated vitrectomy.Methods: Three-port pars plana incisions were generated in six rubber eyes using 23-, 25-, and 27-gauge valved and non-valved trocar cannulas. The models were filled with air and IOP was measured. Similar procedures were followed for 36 acrylic eyes filled with saline solution. Vitreous incarceration was analyzed in eleven rabbit and twelve porcine cadaver eyes.Results: In the air-filled model, IOP loss was 89%–94% when two non-valved cannulas were unoccupied versus 1%–5% when two valved cannulas were unoccupied. In the fluid-filled model, with non-valved cannulas, IOP dropped while fluid leaked from the open ports. With two open ports, the IOP dropped to 20%–30% of set infusion pressure, regardless of infusion pressure and IOP compensation. The IOP was maintained in valved cannulas when one or two ports were left open, regardless of IOP compensation settings. There was no or minimal fluid leakage through open ports at any infusion pressure. Direct microscopic analysis of rabbit eyes showed that vitreous incarceration was significantly greater with 23-gauge non-valved than valved cannulas (P<0.005, and endoscopy of porcine eyes showed that vitreous incarceration was significantly greater with 23-gauge (P<0.05 and 27-gauge (P<0.05 non-valved cannulas. External observation of rabbit eyes showed vitreous prolapse through non-valved, but not valved, cannulas.Conclusion: Valved cannulas surpassed non-valved cannulas in maintaining IOP, preventing fluid leakage, and reducing vitreous incarceration during simulated vitrectomy.Keywords: IOP, fluid leakage, vitreous incarceration

  1. A Valve Design Methodology For Improved Reciprocating Compressor Performance

    OpenAIRE

    Bhakta, Aditya; Dhar, Sandeep; Bahadur, Vaibhav; Angadi, Shruti; Dey, Subhrajit

    2012-01-01

    The current work directly relates valve dynamics to the compressor energy efficiency. Majority of the previous studies have focused on reducing pressure losses due to valve geometry, towards improved compressor performance. On a complimentary note, analyzing the valve ‘flutter’ leads to a holistic valve development methodology. Traditionally, pressure actuated reed valves have been used in reciprocating hermetic compressors on the suction and discharge ports. A characteristic of these valve ...

  2. A computer-checked verification of Milner's scheduler

    OpenAIRE

    Korver, H.; Springintveld, J.

    1993-01-01

    We present an equational verification of Milner's scheduler, which we checked by computer.To our knowledge this is the first time that the scheduler is proof-checked for a general number n of scheduled processes.

  3. Infeasibility of Quantum Cryptography Without Eavesdropping Check

    Science.gov (United States)

    Yang, Wei; Huang, Liusheng; Song, Fang; Wang, Qiyan

    Secure key distribution is impossible in pure classical environment. Unconditional secure key distribution is available when quantum means are introduced, assisted by a classical communication channel. What is possible when a quantum key distribution scheme is without classical communication? We present a general model with this constraint and show that quantum key distribution without classical eavesdropping check is in principle impossible. For an adversary can always succeed in obtaining the secret key via a special case of man-in-the-middle attack, namely intercept-and-forward attack without any risk of being captured.

  4. Political and judicial checks on corruption

    DEFF Research Database (Denmark)

    Alt, James E.; Lassen, David Dreyer

    2008-01-01

    This paper investigates the effects of checks and balances on corruption. Within a presidential system, effective separation of powers is achieved under a divided government, with the executive and legislative branches being controlled by different political parties. When government is unified......, no effective separation exists even within a presidential system, but, we argue, can be partially restored by having an accountable judiciary. Our empirical findings show that a divided government and elected, rather than appointed, state supreme court judges are associated with lower corruption and...

  5. Checking MSC Specifications for Timing Inconsistency

    Institute of Scientific and Technical Information of China (English)

    LI Xuandong(李宣东); TAN Wenkai(谭文凯); ZHENG Guoliang(郑国梁)

    2002-01-01

    Message sequence chart (MSC) is a graphical and textual language for the description and specification of the interactions between system components. MSC specifica tions allow convenient expression of multiple scenarios, and offer an intuitive and visual way of describing design requirements. Like any other aspect of the specification and design process, MSCs are amenable to errors, and their analysis is important. In this paper, the verification problem of MSC specification for timing inconsistency is studied, which means that no execu tion scenario described by an MSC specification is timing consistent. An algorithm is developed to check MSC specifications for timing inconsistency.

  6. 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...... timed automata and most recently hybrid systems using the tool Uppaal SMC. In this paper we enable the application of SMC to complex biological systems, by combining Uppaal SMC with ANIMO, a plugin of the tool Cytoscape used by biologists, as well as with SimBiology®, a plugin of Matlab to simulate...

  7. SAT-Based Model Checking without Unrolling

    Science.gov (United States)

    Bradley, Aaron R.

    A new form of SAT-based symbolic model checking is described. Instead of unrolling the transition relation, it incrementally generates clauses that are inductive relative to (and augment) stepwise approximate reachability information. In this way, the algorithm gradually refines the property, eventually producing either an inductive strengthening of the property or a counterexample trace. Our experimental studies show that induction is a powerful tool for generalizing the unreachability of given error states: it can refine away many states at once, and it is effective at focusing the proof search on aspects of the transition system relevant to the property. Furthermore, the incremental structure of the algorithm lends itself to a parallel implementation.

  8. Automata-Based CSL Model Checking

    DEFF Research Database (Denmark)

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

    2011-01-01

    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. The presented decision procedure, however, has exponential complexity. In this paper, we...... probability can then be approximated in polynomial time (using uniformization). This makes the present work the centerpiece of a broadly applicable full CSL model checker. Recently, the decision algorithm by Aziz et al. was shown to be incorrect in general. In fact, it works only for stratified CTMCs...

  9. Cylinder valve packing nut studies

    Energy Technology Data Exchange (ETDEWEB)

    Blue, S.C. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    The design, manufacture, and use of cylinder valve packing nuts have been studied to improve their resistance to failure from stress corrosion cracking. Stress frozen photoelastic models have been analyzed to measure the stress concentrations at observed points of failure. The load effects induced by assembly torque and thermal expansion of stem packing were observed by strain gaging nuts. The effects of finishing operations and heat treatment were studied by the strain gage hole boring and X-ray methods. Modifications of manufacturing and operation practices are reducing the frequency of stress corrosion failures.

  10. Left atrial ball valve thrombus

    Directory of Open Access Journals (Sweden)

    R. Balaji

    2013-10-01

    Full Text Available "Ball valve thrombus" which is a spherical free floating clot in left atrium is an often quoted, but uncommonly encountered complication in patients with severe mitral stenosis of rheumatic origin, who are in atrial fibrillation. We describe the case of a 31-year-old lady with rheumatic heart disease, severe mitral stenosis and moderately severe aortic stenosis who had undergone closed mitral valvotomy 13 years ago. The patient presented with an episode of non-exertional syncope and breathlessness on exertion of 6 months duration and was in normal sinus rhythm. Echocardiography facilitated ante-mortem diagnosis and prompt institution of surgery was life saving.

  11. Assessment of diagnostic methods for solenoid-operated valves

    International Nuclear Information System (INIS)

    Solenoid-operated valves (SOVs) were studied at Oak Ridge National Laboratory as part of the USNRC Nuclear Plant Aging Research (NPAR) Program. The primary objective of the study was to identify, evaluate, and recommend methods for inspection, surveillance, monitoring, and maintenance of SOVs that can help ensure their operational readiness -- that is, their ability to perform required safety functions under all anticipated operating conditions, since failure of one of these small and relatively inexpensive devices could have serious consequences under certain circumstances. Intrusive techniques requiring the addition of magnetic or acoustic sensors or the application of special test signals were investigated briefly, but major emphasis was placed on the examination of condition-indicating techniques that can be applied with minimal cost and impact on plant operation. These include monitoring coil mean temperature remotely by means of coil dc resistance or ac impedance, determining valve plunger position by means of coil ac impedance, verifying unrestricted SOV plunger movement by measuring current and voltage at their critical bistable (pull-in and drop-out) values, and detecting the presence of shorted turns or insulation breakdown within the solenoid coil using interrupted-current test methods. Experimental results are presented that demonstrate the technical feasibility and praticality of the monitoring techniques assessed in the study, and recommendations for further work are provided

  12. Buckling check tools for plate panel and column structures

    OpenAIRE

    Vuorela, Pia

    2014-01-01

    Buckling is, besides yielding, one of the major causes of failures in structures, and buckling checks are therefore an integral part of strength analyses. Checks can be performed either with methods requiring heavy numerical calculations or with equations based on rules and recommendations from a classification society. Numerical calculations are extremely time-consuming and commercial buckling check programs are expensive. There is therefore a need for buckling check tools based on the recom...

  13. Has percutaneous aortic valve replacement taken center stage in the treatment of aortic valve disease?

    Science.gov (United States)

    Kumar, Gideon Praveen; Cui, Fangsen; Mathew, Lazar; Leo, Hwa Liang

    2013-01-01

    Modern biomedical advances have propelled percutaneous valve replacement into an effective and powerful therapy for many heart valve diseases, especially aortic valve stenosis. Experiences so far suggest that outcomes for new percutaneous valve replacement surgery compare favorably with that of traditional valve surgery in selected patients with severe symptomatic aortic stenosis. The inception of percutaneous aortic valve replacement (PAVR) began in 1992 when the potential for treating valve diseases was demonstrated through a modern technique of endoluminal deployment of a catheter-mounted crimped stented heart valve in an animal model. The first successful demonstration of such novel technique of surgical replacement of a heart valve was performed in 2002, when valve implantation in a patient with aortic stenosis was reported. Despite initial stumbles and a perception of being an uphill task, PAVR has emerged as one of the breakthroughs in surgical procedures. More than 1500 citations were found in PubMed, half of which were available after 2011. This is primarily because more than 50,000 procedures are being performed in more than 40 countries worldwide, with encouraging outcomes, and several stented valves have been launched in the market. This review provides a detailed analysis of the current state of the art of PAVR. Moreover, a competitive landscape of various devices available in the market and their design considerations, biomaterial selections, and overall hemodynamic performance are presented. PMID:24941416

  14. Disruption of silicone valve housing in a Codman Hakim Precision valve with integrated Siphonguard.

    Science.gov (United States)

    Woerdeman, Peter A; Cochrane, David D

    2014-05-01

    Authors of this report describe 2 patients who had undergone shunt insertion for hydrocephalus and who, at 6 weeks or 9 months after their last revision, presented with symptoms of shunt dysfunction and CSF collections at the valve site. At the ensuing shunt revision in both patients, the silicone housing was fractured and the Siphonguard was disconnected from the Codman Hakim Precision flat-bottom valve. The cause of these failures was not clear since manipulation, bending, and twisting of the valves were not thought to have occurred during implantation. A review of the FDA's Manufacturer and User Facility Device Experience (MAUDE) database revealed 58 cases of silicone housing failure in the Codman Hakim Precision valve with integrated Siphonguard since the year 2000. A single report was found in the databases administered by the Canadian Medical Devices Sentinel Network (CMDSNet). The Codman Hakim Precision valves with integrated Siphonguard are delicate devices that do not withstand the intraoperative handling tolerated by other valves. When these valves are implanted, gentle handling and wide exposures are needed to minimize the risk of valve damage. Valves should be handled according to the manufacturer's instructions. However, in light of this particular pattern of failure, it is recommended that the manufacturer redesign this valve to provide handling tolerance that is characteristic of other valves on the market. The featured cases illustrate the importance of the surgeon's role in postmarket surveillance of medical devices and reporting device failures to the responsible agencies and manufacturers. PMID:24635137

  15. Disruption of silicone valve housing in a Codman Hakim Precision valve with integrated Siphonguard.

    Science.gov (United States)

    Woerdeman, Peter A; Cochrane, David D

    2014-05-01

    Authors of this report describe 2 patients who had undergone shunt insertion for hydrocephalus and who, at 6 weeks or 9 months after their last revision, presented with symptoms of shunt dysfunction and CSF collections at the valve site. At the ensuing shunt revision in both patients, the silicone housing was fractured and the Siphonguard was disconnected from the Codman Hakim Precision flat-bottom valve. The cause of these failures was not clear since manipulation, bending, and twisting of the valves were not thought to have occurred during implantation. A review of the FDA's Manufacturer and User Facility Device Experience (MAUDE) database revealed 58 cases of silicone housing failure in the Codman Hakim Precision valve with integrated Siphonguard since the year 2000. A single report was found in the databases administered by the Canadian Medical Devices Sentinel Network (CMDSNet). The Codman Hakim Precision valves with integrated Siphonguard are delicate devices that do not withstand the intraoperative handling tolerated by other valves. When these valves are implanted, gentle handling and wide exposures are needed to minimize the risk of valve damage. Valves should be handled according to the manufacturer's instructions. However, in light of this particular pattern of failure, it is recommended that the manufacturer redesign this valve to provide handling tolerance that is characteristic of other valves on the market. The featured cases illustrate the importance of the surgeon's role in postmarket surveillance of medical devices and reporting device failures to the responsible agencies and manufacturers.

  16. Temperature derivative of the resistance of spin valves

    Energy Technology Data Exchange (ETDEWEB)

    Granville, Simon, E-mail: simon.granville@epfl.c [Institut de Physique des Nanostrutures, Ecole Polytechnique Federale de Lausanne, Station 3, CH-1015 Lausanne (Switzerland); Yu Haiming [Institut de Physique des Nanostrutures, Ecole Polytechnique Federale de Lausanne, Station 3, CH-1015 Lausanne (Switzerland); State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China); Dubois, Julie [Institut de Physique des Nanostrutures, Ecole Polytechnique Federale de Lausanne, Station 3, CH-1015 Lausanne (Switzerland); Ecole des Mines, 60 bd Saint Michel 75006 Paris (France); Gravier, Laurent; Ansermet, Jean-Philippe [Institut de Physique des Nanostrutures, Ecole Polytechnique Federale de Lausanne, Station 3, CH-1015 Lausanne (Switzerland)

    2010-05-15

    Spin-dependent transport properties of nanowires containing individual Co/Cu/Co pseudo-spin valves were investigated by monitoring an AC voltage induced by a temperature oscillation under a continuous DC current. We observed sharp peaks in the field-dependent AC voltage response. These peaks only appear close to the magnetic field range where conventional magnetoresistance shows a reversible and gradual transition. The effect is interpreted as an extra dissipation process with a distinct temperature dependence that occurs in non-collinear magnetic configurations when transverse moment relaxation takes place.

  17. Mitral valve disease in Marfan's syndrome.

    OpenAIRE

    Marlow, N; Gregg, J. E.; Qureshi, S A

    1987-01-01

    Cardiovascular disease in Marfan's syndrome presenting in childhood affects the mitral valve more often than the aortic valve or the aorta, as in adults. Early evaluation of the cardiovascular system is necessary for any child in whom Marfan's syndrome is suspected.

  18. Mitral valve prolapse - report of 3 cases

    International Nuclear Information System (INIS)

    Prolapse of mitral valve is characterized by its unique auscultatory, echocardiographic and angiographic findings and may be associated with various disease entities such as congenital heart disease, coronary heart disease and Marfan's syndrome etc. Authors report recent experience of 3 cases of prolapsed mitral valve, 2 cases associated with A.S.D. and 1 case with Marfan's syndrome.

  19. 49 CFR 195.420 - Valve maintenance.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valve maintenance. 195.420 Section 195.420 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Operation and Maintenance § 195.420 Valve maintenance. (a) Each operator shall maintain each...

  20. Whole Teflon valves for handling droplets.

    Science.gov (United States)

    Cybulski, Olgierd; Jakiela, Slawomir; Garstecki, Piotr

    2016-06-21

    We propose and test a new whole-Teflon gate valve for handling droplets. The valve allows droplet plugs to pass through without disturbing them. This is possible due to the geometric design, the choice of material and lack of any pulses of flow generated by closing or opening the valve. The duct through the valve resembles a simple segment of tubing, without constrictions, change in lumen or side pockets. There are no extra sealing materials with different wettability or chemical resistance. The only material exposed to liquids is FEP Teflon, which is resistant to aggressive chemicals and fully biocompatible. The valve can be integrated into microfluidic systems: we demonstrate a complex system for culturing bacteria in hundreds of microliter droplet chemostats. The valve effectively isolates modules of the system to increase precision of operations on droplets. We verified that the valve allowed millions of droplet plugs to safely pass through, without any cross-contamination with bacteria between the droplets. The valve can be used in automating complex microfluidic systems for experiments in biochemistry, biology and organic chemistry. PMID:27182628

  1. [Anatomic and functional features of venous valves].

    Science.gov (United States)

    Griton, P; Vanet, P; Cloarec, M

    1997-05-01

    The comparison of the venous system in the human organism, and in particular the venous valves of the lower limbs, with studies conducted in animal models helped us to understand better the mechanisms involved in adapting to the upright position and walking. We examined work conducted in several species from the horse to the dog, especially in animals who often take on an upright position such as the chimpanzee and the kangouroo, in search for structures comparable to those in man. Different types of valves can be described in man: flotting valves (bicuspid, pigeon nest valves); reinforced valves (mid-thigh); reinforcing valves (periarticular zone in the knee); finally, "flat" valves which are highly resistant formations but with little anti-back flow action. We also describe valvular structures with muscle cells found in the plantar aspect of the foot and the veins of the quadriceps muscle, these valves may have an active hematopropulsive action (Bassi). These results allowed us to identify certain common points between the structures observed in the posterior legs of certain animals and to propose models for investigating venous diseases. PMID:9480339

  2. Mitral valve repair in acquired dextrocardia.

    Science.gov (United States)

    Elmistekawy, Elsayed; Chan, Vincent; Hynes, Mark; Mesana, Thierry

    2015-10-01

    Surgical correction of valvular heart disease in patients with dextrocardia is extremely rare. We report a surgical case of mitral valve repair in a patient with acquired dextrocardia. Successful mitral valve repair was performed through a right lateral thoracotomy. We describe our surgical strategy and summarize the literature.

  3. Oil pipeline valve automation for spill reduction

    Energy Technology Data Exchange (ETDEWEB)

    Mohitpour, Mo; Trefanenko, Bill [Enbridge Technology Inc, Calgary (Canada); Tolmasquim, Sueli Tiomno; Kossatz, Helmut [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil)

    2003-07-01

    Liquid pipeline codes generally stipulate placement of block valves along liquid transmission pipelines such as on each side of major river crossings where environmental hazards could cause or are foreseen to potentially cause serious consequences. Codes, however, do not stipulate any requirement for block valve spacing for low vapour pressure petroleum transportation, nor for remote pipeline valve operations to reduce spills. A review of pipeline codes for valve requirement and spill limitation in high consequence areas is thus presented along with a criteria for an acceptable spill volume that could be caused by pipeline leak/full rupture. A technique for deciding economically and technically effective pipeline block valve automation for remote operation to reduce oil spilled and control of hazards is also provided. In this review, industry practice is highlighted and application of the criteria for maximum permissible oil spill and the technique for deciding valve automation thus developed, as applied to ORSUB pipeline is presented. ORSUB is one of the three initially selected pipelines that have been studied. These pipelines represent about 14% of the total length of petroleum transmission lines operated by PETROBRAS Transporte S.A. (TRANSPETRO) in Brazil. Based on the implementation of valve motorization on these three pipeline, motorization of block valves for remote operation on the remaining pipelines is intended, depending on the success of these implementations, on historical records of failure and appropriate ranking. (author)

  4. Mitral valve disease—morphology and mechanisms

    Science.gov (United States)

    Levine, Robert A.; Hagége, Albert A.; Judge, Daniel P.; Padala, Muralidhar; Dal-Bianco, Jacob P.; Aikawa, Elena; Beaudoin, Jonathan; Bischoff, Joyce; Bouatia-Naji, Nabila; Bruneval, Patrick; Butcher, Jonathan T.; Carpentier, Alain; Chaput, Miguel; Chester, Adrian H.; Clusel, Catherine; Delling, Francesca N.; Dietz, Harry C.; Dina, Christian; Durst, Ronen; Fernandez-Friera, Leticia; Handschumacher, Mark D.; Jensen, Morten O.; Jeunemaitre, Xavier P.; Le Marec, Hervé; Le Tourneau, Thierry; Markwald, Roger R.; Mérot, Jean; Messas, Emmanuel; Milan, David P.; Neri, Tui; Norris, Russell A.; Peal, David; Perrocheau, Maelle; Probst, Vincent; Pucéat, Michael; Rosenthal, Nadia; Solis, Jorge; Schott, Jean-Jacques; Schwammenthal, Ehud; Slaugenhaupt, Susan A.; Song, Jae-Kwan; Yacoub, Magdi H.

    2016-01-01

    Mitral valve disease is a frequent cause of heart failure and death. Emerging evidence indicates that the mitral valve is not a passive structure, but—even in adult life—remains dynamic and accessible for treatment. This concept motivates efforts to reduce the clinical progression of mitral valve disease through early detection and modification of underlying mechanisms. Discoveries of genetic mutations causing mitral valve elongation and prolapse have revealed that growth factor signalling and cell migration pathways are regulated by structural molecules in ways that can be modified to limit progression from developmental defects to valve degeneration with clinical complications. Mitral valve enlargement can determine left ventricular outflow tract obstruction in hypertrophic cardiomyopathy, and might be stimulated by potentially modifiable biological valvular–ventricular interactions. Mitral valve plasticity also allows adaptive growth in response to ventricular remodelling. However, adverse cellular and mechanobiological processes create relative leaflet deficiency in the ischaemic setting, leading to mitral regurgitation with increased heart failure and mortality. Our approach, which bridges clinicians and basic scientists, enables the correlation of observed disease with cellular and molecular mechanisms, leading to the discovery of new opportunities for improving the natural history of mitral valve disease. PMID:26483167

  5. Mitral valve disease--morphology and mechanisms.

    Science.gov (United States)

    Levine, Robert A; Hagége, Albert A; Judge, Daniel P; Padala, Muralidhar; Dal-Bianco, Jacob P; Aikawa, Elena; Beaudoin, Jonathan; Bischoff, Joyce; Bouatia-Naji, Nabila; Bruneval, Patrick; Butcher, Jonathan T; Carpentier, Alain; Chaput, Miguel; Chester, Adrian H; Clusel, Catherine; Delling, Francesca N; Dietz, Harry C; Dina, Christian; Durst, Ronen; Fernandez-Friera, Leticia; Handschumacher, Mark D; Jensen, Morten O; Jeunemaitre, Xavier P; Le Marec, Hervé; Le Tourneau, Thierry; Markwald, Roger R; Mérot, Jean; Messas, Emmanuel; Milan, David P; Neri, Tui; Norris, Russell A; Peal, David; Perrocheau, Maelle; Probst, Vincent; Pucéat, Michael; Rosenthal, Nadia; Solis, Jorge; Schott, Jean-Jacques; Schwammenthal, Ehud; Slaugenhaupt, Susan A; Song, Jae-Kwan; Yacoub, Magdi H

    2015-12-01

    Mitral valve disease is a frequent cause of heart failure and death. Emerging evidence indicates that the mitral valve is not a passive structure, but--even in adult life--remains dynamic and accessible for treatment. This concept motivates efforts to reduce the clinical progression of mitral valve disease through early detection and modification of underlying mechanisms. Discoveries of genetic mutations causing mitral valve elongation and prolapse have revealed that growth factor signalling and cell migration pathways are regulated by structural molecules in ways that can be modified to limit progression from developmental defects to valve degeneration with clinical complications. Mitral valve enlargement can determine left ventricular outflow tract obstruction in hypertrophic cardiomyopathy, and might be stimulated by potentially modifiable biological valvular-ventricular interactions. Mitral valve plasticity also allows adaptive growth in response to ventricular remodelling. However, adverse cellular and mechanobiological processes create relative leaflet deficiency in the ischaemic setting, leading to mitral regurgitation with increased heart failure and mortality. Our approach, which bridges clinicians and basic scientists, enables the correlation of observed disease with cellular and molecular mechanisms, leading to the discovery of new opportunities for improving the natural history of mitral valve disease.

  6. 46 CFR 64.67 - Shutoff valve.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Shutoff valve. 64.67 Section 64.67 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.67 Shutoff valve. A shutoff...

  7. Inexpensive tamper proof safety relief valve

    Science.gov (United States)

    Frankewich, P. A.

    1970-01-01

    Basic relief valve has added safety relief valve capability that relieves overpressure before failure can occur. It may be installed in inaccesible areas with a high degree of reliability, constructed from a variety of materials, and adapted to the user's specific application.

  8. Transcatheter Aortic Valve Replacement in Europe

    DEFF Research Database (Denmark)

    Mylotte, Darren; Osnabrugge, Ruben L J; Windecker, Stephan;

    2013-01-01

    The authors sought to examine the adoption of transcatheter aortic valve replacement (TAVR) in Western Europe and investigate factors that may influence the heterogeneous use of this therapy.......The authors sought to examine the adoption of transcatheter aortic valve replacement (TAVR) in Western Europe and investigate factors that may influence the heterogeneous use of this therapy....

  9. Heart Valve Disease among Patients with Hyperprolactinaemia

    DEFF Research Database (Denmark)

    Steffensen, Charlotte; Maegbaek, Merete Lund; Laurberg, Peter;

    2012-01-01

    Increased risk of heart valve disease during treatment with certain dopamine agonists, such as cabergoline, has been observed in patients with Parkinson's disease. The same compound is used to treat hyperprolactinemia, but it is unknown whether this also associates with heart valve disease....

  10. 7 CFR 1944.540 - Requesting TSA checks.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 13 2010-01-01 2009-01-01 true Requesting TSA checks. 1944.540 Section 1944.540... TSA checks. (a) The initial TSA check may cover the applicant's needs for the first calendar month. If... the next whole month. (b) The initial advance of TSA grant funds may not be requested...

  11. Testing Intelligently Includes Double-Checking Wechsler IQ Scores

    Science.gov (United States)

    Kuentzel, Jeffrey G.; Hetterscheidt, Lesley A.; Barnett, Douglas

    2011-01-01

    The rigors of standardized testing make for numerous opportunities for examiner error, including simple computational mistakes in scoring. Although experts recommend that test scoring be double-checked, the extent to which independent double-checking would reduce scoring errors is not known. A double-checking procedure was established at a…

  12. Note: A valve-type piezoelectric reciprocating pump with secondary resonant vibrator

    Science.gov (United States)

    Ma, Yu Ting; Wang, Ce; Yan, Xin Tao; Feng, Zhi Hua

    2016-01-01

    A valve-type piezoelectric diaphragm pump using secondary resonant vibrator is introduced in this paper. The secondary resonant vibrator, which is mainly composed of a first vibrator and a second vibrator, is used to coordinate the frequency incompatibility between piezoelectric elements and check valves. The intermittent vibration of the first vibrator excites the resonant vibration of the second vibrator. The diaphragm in the pump chamber moves with the second vibrator, resulting in chamber volume and pressure variations. Control circuit capable of frequency tracking is designed. Vibration displacement and flow rate changing with driving voltage amplitude, frequency, and backpressure are studied in experiments. The flow rate of a prototype driven by voltage of 712 Vpp is 13.94 ml/min at secondary resonant frequency of 6 Hz.

  13. A jazz-based approach for optimal setting of pressure reducing valves in water distribution networks

    Science.gov (United States)

    De Paola, Francesco; Galdiero, Enzo; Giugni, Maurizio

    2016-05-01

    This study presents a model for valve setting in water distribution networks (WDNs), with the aim of reducing the level of leakage. The approach is based on the harmony search (HS) optimization algorithm. The HS mimics a jazz improvisation process able to find the best solutions, in this case corresponding to valve settings in a WDN. The model also interfaces with the improved version of a popular hydraulic simulator, EPANET 2.0, to check the hydraulic constraints and to evaluate the performances of the solutions. Penalties are introduced in the objective function in case of violation of the hydraulic constraints. The model is applied to two case studies, and the obtained results in terms of pressure reductions are comparable with those of competitive metaheuristic algorithms (e.g. genetic algorithms). The results demonstrate the suitability of the HS algorithm for water network management and optimization.

  14. Model-Based Trace-Checking

    CERN Document Server

    Howard, Y; Gravell, A; Ferreira, C; Augusto, J C

    2011-01-01

    Trace analysis can be a useful way to discover problems in a program under test. Rather than writing a special purpose trace analysis tool, this paper proposes that traces can usefully be analysed by checking them against a formal model using a standard model-checker or else an animator for executable specifications. These techniques are illustrated using a Travel Agent case study implemented in J2EE. We added trace beans to this code that write trace information to a database. The traces are then extracted and converted into a form suitable for analysis by Spin, a popular model-checker, and Pro-B, a model-checker and animator for the B notation. This illustrates the technique, and also the fact that such a system can have a variety of models, in different notations, that capture different features. These experiments have demonstrated that model-based trace-checking is feasible. Future work is focussed on scaling up the approach to larger systems by increasing the level of automation.

  15. Model Checking of Boolean Process Models

    CERN Document Server

    Schneider, Christoph

    2011-01-01

    In the field of Business Process Management formal models for the control flow of business processes have been designed since more than 15 years. Which methods are best suited to verify the bulk of these models? The first step is to select a formal language which fixes the semantics of the models. We adopt the language of Boolean systems as reference language for Boolean process models. Boolean systems form a simple subclass of coloured Petri nets. Their characteristics are low tokens to model explicitly states with a subsequent skipping of activations and arbitrary logical rules of type AND, XOR, OR etc. to model the split and join of the control flow. We apply model checking as a verification method for the safeness and liveness of Boolean systems. Model checking of Boolean systems uses the elementary theory of propositional logic, no modal operators are needed. Our verification builds on a finite complete prefix of a certain T-system attached to the Boolean system. It splits the processes of the Boolean sy...

  16. Improved Message Authentication and Confidentiality Checking

    International Nuclear Information System (INIS)

    The most confusing areas of the secured network communications are the message authentication and confidentiality checking. The attacks and the counter measures have become so convoluted that the users in this area begin to account for all contingencies. Two session-key generation techniques are used here to generate two separate session keys K1 and K2; and both the sender and the reveiver share these keys for higher degree of authentication and confidentiality. For this, the message is first encrypted by the key K1, and then the intermediary message authenticatin code (MAC) is generated by encrypting the encrypted message using the key K2. Then, the encrypted message and the intermediary MAC is again encrypted by using the K2 and concatenated with the encrypted message and sent to the destination. At the receiving end, first, the received ciphertext is encrypted by using key K2 and compared to the received MAC. The received ciphertext again is decrypted by the key K2 and compared with the first decrypted MAC twice by the key K2. The plaintext is obtained by decrypting the received ciphertext first by K2 and then by K1, using the corresponding decryption techniques respectively. The encryption techniques with key K2 provides the authentication and with key K1 provides the confidentiality checking of the transmitted message. The developed technique can be applied to both academic and commercial applications in online or offline electronic transactions for security.(authors)

  17. Model Checking over Paraconsistent Temporal Logic

    Institute of Scientific and Technical Information of China (English)

    CHEN Dong-huo; WANG Lin-zhang; CUI Jia-lin

    2008-01-01

    Classical logic cannot be used to effectively reason about concurrent systems with inconsistencies (inconsistencies often occur, especially in the early stage of the development, when large and complex concurrent systems are developed). In this paper, we propose the use of a guasi-classical temporal logic (QCTL) for supporting the verification of temporal properties of such systems even where the consistent model is not available. Our models are paraKripke structures ( extended standard Kripke structures), in which both a formula and its negation are satisfied in a same state, and properties to be verified are expressed by QCTL with paraKripke structures semantics. We introduce a novel notion of paraKripke models, which grasps the paraconsistent character of the entailment relation of QCTL. Furthermore, we explore the methodology of model checking over QCTL, and describe the detailed algorithm of implementing QCTL model checker. In the sequel, a simple example is presented, showing how to exploit the proposed model checking technique to verify the temporal properties of inconsistent concurrent systems.

  18. [Heart valves after 22 years - good long-term function of aortic homograft, advanced impairment in function of atrioventricular valves].

    Science.gov (United States)

    Michalski, Błazej; Chrzanowski, Lukasz; Krzemińska-Pakula, Maria; Kasprzak, Jarosław D

    2010-03-01

    We report a case of a 61-year-old female patient with a history of aortic valve replacement, who was admitted to our hospital with symptoms and signs of decompensated heart failure (NYHA class III). Transthoracic echocardiogram revealed mitral valve and tricuspid valve regurgitation (III grade) with normal function of aortic valve homograft implanted 22 years ago. The patient underwent cardiosurgical mitral valve replacement and tricuspid valve annuloplasty with very good result. An aortic valve homograft may be the best alternative to a mechanical valves for a young female patients. PMID:20411462

  19. Intraoperative tracking of aortic valve plane

    Science.gov (United States)

    Nguyen, Duc Long Hung; Garreau, Mireille; Auffret, Vincent; Le Breton, Hervé; Verhoye, Jean-Philippe; Haigron, Pascal

    2013-01-01

    The main objective of this work is to track the aortic valve plane in intra-operative fluoroscopic images in order to optimize and secure Transcatheter Aortic Valve Implantation (TAVI) procedure. This paper is focused on the issue of aortic valve calcifications tracking in fluoroscopic images. We propose a new method based on the Tracking-Learning-Detection approach, applied to the aortic valve calcifications in order to determine the position of the aortic valve plane in intra-operative TAVI images. This main contribution concerns the improvement of object detection by updating the recursive tracker in which all features are tracked jointly. The approach has been evaluated on four patient databases, providing an absolute mean displacement error less than 10 pixels ≈ 2mm). Its suitability for the TAVI procedure has been analyzed. PMID:24110703

  20. Transcatheter mitral valve implantation via transapical approach

    DEFF Research Database (Denmark)

    Sondergaard, Lars; Brooks, Matthew; Ihlemann, Nikolaj;

    2015-01-01

    OBJECTIVES: As many as 50% of patients with severe symptomatic mitral valve regurgitation are denied surgical valve replacement or repair due to high operative risk. We describe an early series of cases of transcatheter implantation with a CardiAQ™ mitral valve via a transapical approach. METHODS......: Three consecutive patients with an Society of Thoracic Surgeons (STS) mortality score of >22% were selected for transcatheter mitral valve implantation (TMVI) on compassionate grounds. All patients were elderly, had severe mitral regurgitation (MR), were in Class IV heart failure and deemed unsuitable...... bypass surgery (n = 2), severe pulmonary hypertension (n = 1) and moderate to severe chronic renal failure (n = 3). A CardiAQ mitral valve was implanted using fluoroscopy and transoesophageal (TEE) guidance via a standard transapical approach. RESULTS: Accurate prosthesis positioning and deployment...