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Sample records for valve means disposed

  1. Control of an air pressure actuated disposable bioreactor for cultivating heart valves

    NARCIS (Netherlands)

    Beelen, M.J.; Neerincx, P.E.; Molengraft, van de M.J.G.

    2011-01-01

    A disposable injection molded bioreactor for growing tissue-engineered heart valves is controlled to mimic the physiological heart cycle. Tissue-engineered heart valves, cultured from human stem cells, are a possible alternative for replacing failing aortic heart valves, where nowadays biological

  2. 3D velocity field characterization of prosthetic heart valve with two different valve testers by means of stereo-PIV.

    Science.gov (United States)

    D'Avenio, Giuseppe; Grigioni, Mauro; Daniele, Carla; Morbiducci, Umberto; Hamilton, Kathrin

    2015-01-01

    Prosthetic heart valves can be associated to mechanical loading of blood, potentially linked to complications (hemolysis and thrombogenicity) which can be clinically relevant. In order to test such devices in pulsatile mode, pulse duplicators (PDs) have been designed and built according to different concepts. This study was carried out to compare anemometric measurements made on the same prosthetic device, with two widely used PDs. The valve (a 27-mm bileaflet valve) was mounted in the aortic section of the PD. The Sheffield University PD and the RWTH Aachen PD were selected as physical models of the circulation. These two PDs differ mainly in the vertical vs horizontal realization, and in the ventricular section, which in the RWTH PD allows for storage of potential energy in the elastic walls of the ventricle. A glassblown aorta, realized according to the geometric data of the same anatomical district in healthy individuals, was positioned downstream of the valve, obtaining 1:1 geometric similarity conditions. A NaI-glycerol-water solution of suitable kinematic viscosity and, at the same time, the proper refractive index, was selected. The flow field downstream of the valve was measured by means of the stereo-PIV (Particle Image Velocimetry) technique, capable of providing the complete 3D velocity field as well as the entire Reynolds stress tensor. The measurements were carried out at the plane intersecting the valve axis. A three-jet profile was clearly found in the plane crossing the leaflets, with both PDs. The extent of the typical recirculation zone in the Valsalva sinus was much larger in the RWTH PD, on account of the different duration of the swirling motion in the ventricular chamber, caused by the elasticity of the ventricle and its geometry. The comparison of the hemodynamical behaviour of the same bileaflet valve tested in two PDs demonstrated the role of the mock loop in affecting the valve performance.

  3. Can postoperative mean transprosthetic pressure gradient predict survival after aortic valve replacement?

    NARCIS (Netherlands)

    Koene, Bart M.; Hamad, Mohamed A. Soliman; Bouma, Wobbe; Mariani, Massimo A.; Peels, Kathinka C.; van Dantzig, Jan-Melle; van Straten, Albert H.

    In this study, we sought to determine the effect of the mean transprosthetic pressure gradient (TPG), measured at 6 weeks after aortic valve replacement (AVR) or AVR with coronary artery bypass grafting (CABG) on late all-cause mortality. Between January 1998 and March 2012, 2,276 patients (mean age

  4. Rapid patterning of 'tunable' hydrophobic valves on disposable microchips by laser printer lithography.

    Science.gov (United States)

    Ouyang, Yiwen; Wang, Shibo; Li, Jingyi; Riehl, Paul S; Begley, Matthew; Landers, James P

    2013-05-07

    We recently defined a method for fabricating multilayer microdevices using poly(ethylene terephthalate) transparency film and printer toner, and showed these could be successfully applied to DNA extraction and amplification (Duarte et al., Anal. Chem. 2011, 83, 5182-5189). Here, we advance the functionality of these microdevices with flow control enabled by hydrophobic valves patterned using laser printer lithography. Laser printer patterning of toner within the microchannel induces a dramatic change in surface hydrophobicity (change in contact angle of DI water from 51° to 111°) with good reproducibility. Moreover, the hydrophobicity of the surface can be controlled by altering the density of the patterned toner via varying the gray-scale setting on the laser printer, which consequently tunes the valve's burst pressure. Toner density provided a larger burst pressure bandwidth (158 ± 18 Pa to 573 ± 16 Pa) than could be achieved by varying channel geometry (492 ± 18 Pa to 573 ± 16 Pa). Finally, we used a series of tuned toner valves (with varied gray-scale) for passive valve-based fluidic transfer in a predictable manner through the architecture of a rotating PeT microdevice. While an elementary demonstration, this presents the possibility for simplistic and cost-effective microdevices with valved fluid flow control to be fabricated using nothing more than a laser printer, a laser cutter and a laminator.

  5. Magnetically operated check valve

    Science.gov (United States)

    Morris, Brian G.; Bozeman, Richard J., Jr.

    1994-06-01

    A magnetically operated check valve is disclosed. The valve is comprised of a valve body and a movable poppet disposed therein. A magnet attracts the poppet to hold the valve shut until the force of fluid flow through the valve overcomes the magnetic attraction and moves the poppet to an unseated, open position. The poppet and magnet are configured and disposed to trap a magnetically attracted particulate and prevent it from flowing to a valve seating region.

  6. Evaluation of steady flow torques and pressure losses in a rotary flow control valve by means of computational fluid dynamics

    International Nuclear Information System (INIS)

    Okhotnikov, Ivan; Noroozi, Siamak; Sewell, Philip; Godfrey, Philip

    2017-01-01

    Highlights: • A novel design of a rotary flow control valve driven by a stepper motor is proposed. • The intended use of the valve in the high flow rate independent metering hydraulic system is suggested. • Pressure drops, steady flow torques of the valve for various flow rates and orifice openings are studied by means of computational fluid dynamics. • The discharge coefficient and flow jet angles dependencies on the orifice opening are obtained. • A design method to decrease the flow forces without reducing the flow rate in single-staged valves is demonstrated. - Abstract: In this paper, a novel design of a rotary hydraulic flow control valve has been presented for high flow rate fluid power systems. High flow rates in these systems account for substantial flow forces acting on the throttling elements of the valves and cause the application of mechanically sophisticated multi-staged servo valves for flow regulation. The suggested design enables utilisation of single-stage valves in power hydraulics operating at high flow rates regimes. A spool driver and auxiliary mechanisms of the proposed valve design were discussed and selection criteria were suggested. Analytical expressions for metering characteristics as well as steady flow torques have been derived. Computational fluid dynamics (CFD) analysis of steady state flow regimes was conducted to evaluate the hydraulic behaviour of the proposed valve. This study represents a special case of an independent metering concept applied to the design of power hydraulic systems with direct proportional valve control operating at flow rates above 150 litres per minute. The result gained using parametric CFD simulations predicted the induced torque and the pressure drops due to a steady flow. Magnitudes of these values prove that by minimising the number of spool's mobile metering surfaces it is possible to reduce the flow-generated forces in the new generation of hydraulic valves proposed in this study

  7. Control Valve

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Wayne R.

    2018-03-20

    A control valve includes a first conduit having a first inlet and a first outlet and defining a first passage; a second conduit having a second inlet and a second outlet and defining a second passage, the second conduit extending into the first passage such that the second inlet is located within the first passage; and a valve plate disposed pivotably within the first passage, the valve plate defining a valve plate surface. Pivoting of the valve plate within the first passage varies flow from the first inlet to the first outlet and the valve plate is pivotal between a first position and a second position such that in the first position the valve plate substantially prevents fluid communication between the first passage and the second passage and such that in the second position the valve plate permits fluid communication between the first passage and the second passage.

  8. Evaluation of the flow forces on an open centre directional control valve by means of a computational fluid dynamic analysis

    International Nuclear Information System (INIS)

    Amirante, R.; Del Vescovo, G.; Lippolis, A.

    2006-01-01

    The aim of the present paper is the evaluation of the driving forces acting on a 4/3 hydraulic open center directional control valve spool by means of a complete numerical analysis. In a previous paper by the same authors, the valve was inserted in a closed hydraulic circuit and was tested with different pump flow rate values to obtain experimental results about the driving forces. The experimental results are used in this paper to evaluate and validate the numerical analysis of the valve. The obtained numerical results show important differences between an open center valve and a closed center one, the latter being extensively analyzed in the literature. The numerical analysis is performed by using the commercial code 'Fluent', and the numerical results show the complete flow field inside the valve. The aim of this analysis is to evaluate the valve fluid dynamic performance, exploiting computational fluid dynamics (CFD) techniques, in order to give the reliable indications needed to define the valve design criteria and avoid expensive experimental tests

  9. Fast-Valving of Large Steam Turbine Units as a Means of Power System Security Enhancement

    Directory of Open Access Journals (Sweden)

    Bogdan Sobczak

    2014-03-01

    Full Text Available Fast-valving assists in maintaining system stability following a severe transmission system fault by reducing the turbine mechanical power. Fast-valving consists in rapid closing and opening of steam valves in an adequate manner to reduce the generator accelerating power following the recognition of a severe fault. FV can be an effective and economical method of meeting the performance requirements of a power system in the presence of an increase in wind and solar generation in the power system, newly connected large thermal units and delaying of building new transmission lines. The principle of fast-valving and advantages of applying this technique in large steam turbine units was presented in the paper. Effectiveness of fast-valving in enhancing the stability of the Polish Power Grid was analyzed. The feasibility study of fast-valving application in the 560 MW unit in Kozienice Power Station (EW SA was discussed.

  10. Fast-Valving of Large Steam Turbine Units as a Means of Power System Security Enhancement

    OpenAIRE

    Bogdan Sobczak; Robert Rink; Rafał Kuczyński; Robert Trębski

    2014-01-01

    Fast-valving assists in maintaining system stability following a severe transmission system fault by reducing the turbine mechanical power. Fast-valving consists in rapid closing and opening of steam valves in an adequate manner to reduce the generator accelerating power following the recognition of a severe fault. FV can be an effective and economical method of meeting the performance requirements of a power system in the presence of an increase in wind and solar generation in the power syst...

  11. A microfluidic control system with re-usable micropump/valve actuator and injection moulded disposable polymer lab-on-a-slide

    DEFF Research Database (Denmark)

    Bu, Minqiang; Perch-Nielsen, Ivan R.; Yi, Sun

    2011-01-01

    A microfluidic control system consisting of micropump/valves with a re-usable pneumatic actuator and a disposable polymer lab-on-a-slide is presented. The lab-on-a-slide was fabricated using low cost methods, such as injection moulding of TOPAS® cyclic olefin copolymer (COC) slide, lamination...... of different layers of polymer, and ultrasonic welding of TOPAS® lid to the slide. The re-usable pneumatic actuator not only simplifies the design of the lab-on-a-slide and reduces the fabrication cost, but also reduces the possibility of cross contamination during replacement of the disposable lab...

  12. Flow Rate Analysis of 3/2 Directional Pneumatic Valve by Means Of Ansys Cfx Software

    Directory of Open Access Journals (Sweden)

    Slawomir BLASIAK

    2014-12-01

    Full Text Available The main purpose of this paper was to develop a selection method of the pneumatic connectors for directional 3/2 valve. The method was established to minimize resistance and loss of pressure in the valve with mounted pneumatic connections for the selected pipe diameters. Directional valve was modeled in 3D CAD software SolidWorks while 3D models of the air connections have been downloaded from the website of one of the leading suppliers of pneumatic. Based on developed solid model the simulation of compressed air flow in the software for computational fluid dynamics Ansys CFX was conducted. The studies using CFD methods helped to determine which air connections best meet the assumptions. Performed numerical tests enable proper selection of items to the newly designed pneumatic systems for a particular group of valves. As a consequence, this translates into a reduction in energy consumption and improve the efficiency of the entire pneumatic complex system.

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

    International Nuclear Information System (INIS)

    Lee, M. R.; Lee, J. H.; Kim, J. T.; Kim, J. S.; Luk, V. K.

    2003-01-01

    This work performed in support of the International Nuclear Energy Research Institute (INERI) program, which was to develop and demonstrate advanced sensor and computational technology for on-line monitoring of the condition of components, structures, and systems in advanced and next-generation nuclear power plants (NPPs). This primary object of this work is to investigate advanced condition monitoring systems based on acoustic emission detection that can provide timely detection of check valve degeneration and service aging so that maintenance/replacement could be preformed prior to loss safety function. The research is focused on the capability of AE technique to provide diagnostic information useful in determining check valve aging and degradation check valve failure and undesirable operating modes. This work also includes the investigation and adaptation of several advanced sensor technologies such as accelerometer and advanced ultrasonic technique. In addition, this work will develop advanced sophisticated signal processing, noise reduction, and pattern recognition techniques and algorithms from check valve degradation.

  14. Subsurface waste disposal by means of wells - A selective annotated bibliography

    Science.gov (United States)

    Rima, Donald Robert; Chase, Edith B.; Myers, Beverly M.

    1971-01-01

    Subsurface waste disposal by means of wells is the practice of using drilled wells to inject unwanted substances into underground rock formations. The use of wells for this purpose is not a new idea. As long ago as the end of the last century, it was common practice to drill wells for the express purpose of draining swamps and small lakes to reclaim the land for agricultural purposes. A few decades later in the 1920's and 1930's many oil companies began using injection wells to dispose of oil-field brines and to repressurize oil reservoirs. During World War II, the Atomic Energy Commission began using injection wells to dispose of certain types of radioactive wastes. More recently, injection wells have been drilled to dispose of a variety of byproducts of industrial processes. The number of such wells has increased rapidly since Congress passed the Clean Streams Act of 1966, which restricted the discharge of waste into surface waters.Many scientists and public officials question the propriety of using the term "disposal" when referring to the underground injection of wastes. Their reasons are that underground injection is not, as many advocates claim, "a complete and final answer" to the waste-disposal problem. Rather, it is merely a process wherein the injected wastes are committed to the subsurface with uncertainty as to their ultimate fate or limits of confinement. In effect, the wastes, undiminished and unchanged, are removed from the custody of man and placed in the custody of nature.Although the concept of waste-injection wells is relatively simple, the effects of waste injection can be very complex, particularly when dealing with the exotic and complex components of some industrial wastes. Besides the physical forces of injection, there are many varied interactions between the injected wastes and the materials within the injection zone. Because these changes occur out of sight in the subsurface, they are difficult to assess and not generally understood. In

  15. Modernizing the 5G 100/8 piston compressor by means of directly streaming valves

    Energy Technology Data Exchange (ETDEWEB)

    Tsvetanov, Ts.; Stoyanov, I.

    1988-02-01

    Deals with 5G 100/8 air compressors which, despite long service and lack of spare parts, are still widely used in Bulgarian underground coal mines. K-4-10 ring-type valves are in particularly short supply; maintenance engineers have been forced to modify the compresors. Initially, Bulgarian KP-3.1 valves with direct air streaming replaced the K-4-10; these were later replaced by PIK-220 and PIK-220A valves. Tests on overhauled compressors have shown that replacing the KP-3.1 with the PIK-220 or PIK-220A can result in a saving of up to 100,000 kWh of electricity per compressor. Details of reconstruction and testing of piston compressors are included. 10 refs.

  16. Material and energy balances of technical means in horticulture and farming - from production to disposal

    International Nuclear Information System (INIS)

    1993-01-01

    The twenty papers of this progress report, which are not individually recorded, belong to either one of the subject areas ''material and energy balances of technical means in horticulture and forming from production to disposal'' and ''plastics in construction and technical systems''. The first-mentioned subject area deals with balances for technical means at horticultural enterprises, greenhouse constructions, and styrofoam in farm buildings, and comprises short papers on sewage treatment plants in the form of beds of plants and ecological aspects of horticultural activities in open spaces. The second subject area mainly concerns recycling and multiple uses of plastics (silage and protective foils) as well as air-flow thermal collector systems. Advances in the construction and use of foil-covered greenhouses and experience with protective nets for plant cultures, energy shields, and shading are reported. (UWA) [de

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

    International Nuclear Information System (INIS)

    Lee, Min Rae; Leee, Jun Hyun; Kim, Jung Tack; Kim, Jung Soo; Luk, V. K.

    2003-01-01

    This work performed in support of the International Nuclear Energy Research Initiative(INERI) program, which was to develop and demonstrate advanced sensor and computational technology for on-line monitoring of the condition of components, structures, and systems in advanced and next-generation nuclear power plants (NPPs). The primary object of this work is to investigate advanced condition monitoring systems based on acoustic emission detection that can provide timely detection of check valve degradation and service aging so that maintenance/replacement could be preformed prior to loss of safety function. The research is focused on the capability of AE technique to provide diagnostic information useful in determining check valve aging and degradation, check valve failures and undesirable operating modes. This work also includes the investigation and adaptation of several advanced sensor technologies such as accelerometer and advanced ultrasonic technique. In addition, this work will develop advanced sophisticated signal processing, noise reduction, and pattern recognition techniques and algorithms from check valve degradation.

  18. [Discordance between mitral valve area (MVA) and pressure gradient in patients with mitral valve stenosis: mean transmitral valve gradient is a severity index or a tolerance index of severity of mitralss valve stenosis?

    Science.gov (United States)

    Najih, Hayat; Arous, Salim; Laarje, Aziza; Baghdadi, Dalila; Benouna, Mohamed Ghali; Azzouzi, Leila; Habbal, Rachida

    2016-01-01

    Rheumatic mitral valve stenosis (MVS) is a frequent valvulopathy in developing countries. However, industrialized countries have seen the emergence of new etiologies of MVS in recent years, in particular drug-induced and/or toxic valvular regurgitation and stenosis. For this reason, the echocardiographic assessment of MVS and especially the definition of objective diagnostic criteria for severe MVS remains relevant. The objectives are: to determine whether there is a direct causal link between mean transmitral gradient (MTG) and severity of MVS in patients with severe MVS or true severe MVS (primary criterion); to analyze different parameters determining mean transmitral gradient (MTG) (secondary criterion). We conducted a single-center cross-sectional study including all patients with severe or true severe MVS admitted to the Department of Cardiology, University Hospital Ibn Rushd, Casablanca over a period of one year (January 2014-December 2014). We analyzed data from two groups of patients separately: those with a mean transmitral gradientgradient>10mmHg (group 2). 50 patients with severe or true severe MVS have been included in the study. The average age of our patients was 41.7 years with a female predominance (sex ratio 0,25). 64% of patients had severe MVS and 36% of patients had true severe MVS. 52% (26 patients) had MTG gradient> 10mmHg, suggesting no direct correlation between the severity of MVS and MTG (Pearson's correlation coefficient R: -0,137). With regards to dyspnea, 80% of patients of group 1 had stage II NYHA dyspnea (classification system) and 70% of patients of group 2 had stage III NYHA dyspnea (41%) or IV NYHA dyspnea (29%), which means that there was a significant correlation between MTG and the severity of dyspnea (R: 0,586 and p: 0,001). The analytical study of heart rate and the presence of cardiac decompensation compared with mean gradient transmitral showed a significant correlation. Indeed, among patients in group 1, 96% had HR

  19. Scissor thrust valve actuator

    Science.gov (United States)

    DeWall, Kevin G.; Watkins, John C; Nitzel, Michael E.

    2006-08-29

    Apparatus for actuating a valve includes a support frame and at least one valve driving linkage arm, one end of which is rotatably connected to a valve stem of the valve and the other end of which is rotatably connected to a screw block. A motor connected to the frame is operatively connected to a motor driven shaft which is in threaded screw driving relationship with the screw block. The motor rotates the motor driven shaft which drives translational movement of the screw block which drives rotatable movement of the valve driving linkage arm which drives translational movement of the valve stem. The valve actuator may further include a sensory control element disposed in operative relationship with the valve stem, the sensory control element being adapted to provide control over the position of the valve stem by at least sensing the travel and/or position of the valve stem.

  20. Planning of a supply chain for anti-personal landmine disposal by means of robots

    Directory of Open Access Journals (Sweden)

    Rafael Guillermo García-Cáceres

    2012-09-01

    Full Text Available The current paper presents a Mixed-Integer-Linear Programming Model (MIP which incorporates strategic and tactical management decisions into the supply chain of an anti-personal landmine robotic detection and disposal system. Originally based on a mixed-integer-non-linear programming model (MINLP with stochastic elements, of which it is an approximation, the MIP model is obtained by means of two solution procedures that include redefining variables, treating stochastic and non-linear constraints, and incorporating valid constraints. The model included considerations such as uncertain procurement, stochastic inventories in plants, production scales, supply-production-distribution capacities, particular distribution-production infrastructure, locationallocation considerations, stochastic demand, and BOM. Additionally, the models detail optimal helicopter operation by considering each period’s trip frequency during the planning horizon. Finally, a sensibility analysis of the way in which parameters variations affect overall costs is presented. The suggested solution procedure is considered satisfactory in terms of time for the analyzed example.

  1. Diseases of the Tricuspid Valve

    Science.gov (United States)

    ... stenosis. Tricuspid Regurgitation Tricuspid regurgitation is also called tricuspid insufficiency or tricuspid incompetence. It means there is a ... require valve surgery. Tags: heart valves , tricuspid incompetence , ... tricuspid regurgitation , tricuspid stenosis , valve disease Related Links ...

  2. Experimental investigations on the fluid-mechanics of an electrospun heart valve by means of particle image velocimetry.

    Science.gov (United States)

    Del Gaudio, Costantino; Gasbarroni, Pier Luca; Romano, Giovanni Paolo

    2016-12-01

    End-stage failing heart valves are currently replaced by mechanical or biological prostheses. Both types positively contribute to restore the physiological function of native valves, but a number of drawbacks limits the expected performances. In order to improve the outcome, tissue engineering can offer an alternative approach to design and fabricate innovative heart valves capable to support the requested function and to promote the formation of a novel, viable and correctly operating physiological structure. This potential result is particularly critical if referred to the aortic valve, being the one mainly exposed to structural and functional degeneration. In this regard, the here proposed study presents the fabrication and in vitro characterization of a bioresorbable electrospun heart valve prosthesis using the particle image velocimetry technique either in physiological and pathological fluid dynamic conditions. The scaffold was designed to reproduce the aortic valve geometry, also mimicking the fibrous structure of the natural extracellular matrix. To evaluate its performances for possible implantation, the flow fields downstream the valve were accurately investigated and compared. The experimental results showed a correct functionality of the device, supported by the formation of vortex structures at the edge of the three cusps, with Reynolds stress values below the threshold for the risk of hemolysis (which can be comprised in the range 400-4000N/m(2) depending on the exposure period), and a good structural resistance to the mechanical loads generated by the driving pressure difference. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Evaluation of the flow forces on a direct (single stage) proportional valve by means of a computational fluid dynamic analysis

    International Nuclear Information System (INIS)

    Amirante, R.; Moscatelli, P.G.; Catalano, L.A.

    2007-01-01

    The aim of this paper is to investigate the fluid dynamic behaviour of a commercial hydraulic proportional valve in order to evaluate and justify its global performances and, in particular, to analyze the effects of some additional design features on the reduction of the force required to maintain the valve open. The proposed analysis has been performed by applying the commercial computational fluid dynamics (CFD) code, Fluent, to the solution of the three dimensional turbulent flow field through a circumferential sector of the entire valve for different spool strokes. The reliability of the employed modelization is demonstrated by the comparison between the computed flow rate curve and the corresponding experimental data provided by the manufacturer. With regard to the metering edge design, it is shown that the cylindrical hole provided on the top of the hemi-spherical notch to improve metering at small valve openings has no influence on the flow force balance. The presented results also demonstrate that compensation techniques based on an adequate spool profiling are effective in balancing the flow forces mainly at medium and large valve openings, thanks to the pressure difference on the compensation profile; which also results in an increased axial momentum at the inlet of the high pressure chamber. The benefits of its presence are amplified by the adoption of two grooves machined on the valve body, which modify the flow field so as both to increase the axial momentum at the inlet of the high pressure chamber and to reduce it at the outlet

  4. Lab-on-a-Valve Mesofluidic Platform for On-Chip Handling of Carbon-Coated Titanium Dioxide Nanotubes in a Disposable Microsolid Phase-Extraction Mode.

    Science.gov (United States)

    García-Valverde, María Teresa; Rosende, María; Lucena, Rafael; Cárdenas, Soledad; Miró, Manuel

    2018-04-03

    Mesofluidic lab-on-a-valve (LOV) platforms have been proven suitable to accommodate automatic micro-solid-phase extraction (μSPE) approaches with on-chip handling of micrometer-bead materials in a fully disposable mode to prevent sample cross-contamination and pressure-drop effects. The efficiency of the extraction process notably depends upon the sorptive capacity of the material because the sorbent mass is usually down to 10 mg in LOV devices. Nanomaterials, capitalizing upon their enhanced surface-to-volume ratio and diversity of potential chemical moieties, are appealing alternatives to microbead sorbents. However, the handling and confinement of nanomaterials in fluidic chip structures have been challenging to date. This is most likely a consequence of the aggregation tendency of a number of nanomaterials, including carbon-based sorbents, that leads to excessive back-pressure in flowing systems along with irreproducible bead loading. This paper addresses these challenges by ad hoc synthesis of hybrid nanomaterials, such as porous carbon-coated titanium dioxide nanotubes (TiO 2 -NT@pC). Tailoring of the surface polarity of the carbon coating is proven to foster the dispersion of TiO 2 -NT@pC in LOV settings while affording superior extraction capability of moderately nonpolar species from aqueous matrices. The determination of trace-level concentrations of butylparaben (BPB) and triclosan (TCS) in seawater samples is herein selected as a proof-of-concept of the exploitation of disposable nanomaterials in LOV. The mesofluidic platform accommodating μSPE features online hyphenation to liquid chromatography/tandem mass spectrometry (LC/MS/MS) for reliable determination of the target analytes with excellent limits of detection (0.5 and 0.6 ng/L for BPB and TCS, respectively) and intermediate precision (relative standard deviation <5.8%). For 5.0 mL of sample and 200 μL of eluent, enrichment factors of 23 and 14 with absolute extraction efficiencies of 90% ± 14

  5. Overflow control valve

    International Nuclear Information System (INIS)

    Kessinger, B.A.; Hundal, R.; Parlak, E.A.

    1982-01-01

    An overflow control valve for use in a liquid sodium coolant pump tank which can be remotely engaged with and disengaged from the pump tank wall to thereby permit valve removal. An actuating shaft for controlling the valve also has means for operating a sliding cylinder against a spring to retract the cylinder from sealing contact with the pump tank nozzle. (author)

  6. Bioprosthetic Valve Fracture Improves the Hemodynamic Results of Valve-in-Valve Transcatheter Aortic Valve Replacement.

    Science.gov (United States)

    Chhatriwalla, Adnan K; Allen, Keith B; Saxon, John T; Cohen, David J; Aggarwal, Sanjeev; Hart, Anthony J; Baron, Suzanne J; Dvir, Danny; Borkon, A Michael

    2017-07-01

    Valve-in-valve (VIV) transcatheter aortic valve replacement (TAVR) may be less effective in small surgical valves because of patient/prosthesis mismatch. Bioprosthetic valve fracture (BVF) using a high-pressure balloon can be performed to facilitate VIV TAVR. We report data from 20 consecutive clinical cases in which BVF was successfully performed before or after VIV TAVR by inflation of a high-pressure balloon positioned across the valve ring during rapid ventricular pacing. Hemodynamic measurements and calculation of the valve effective orifice area were performed at baseline, immediately after VIV TAVR, and after BVF. BVF was successfully performed in 20 patients undergoing VIV TAVR with balloon-expandable (n=8) or self-expanding (n=12) transcatheter valves in Mitroflow, Carpentier-Edwards Perimount, Magna and Magna Ease, Biocor Epic and Biocor Epic Supra, and Mosaic surgical valves. Successful fracture was noted fluoroscopically when the waist of the balloon released and by a sudden drop in inflation pressure, often accompanied by an audible snap. BVF resulted in a reduction in the mean transvalvular gradient (from 20.5±7.4 to 6.7±3.7 mm Hg, P valve effective orifice area (from 1.0±0.4 to 1.8±0.6 cm 2 , P valves to facilitate VIV TAVR with either balloon-expandable or self-expanding transcatheter valves and results in reduced residual transvalvular gradients and increased valve effective orifice area. © 2017 American Heart Association, Inc.

  7. Heart valve surgery

    Science.gov (United States)

    ... replacement; Valve repair; Heart valve prosthesis; Mechanical valves; Prosthetic valves ... surgery. Your heart valve has been damaged by infection ( endocarditis ). You have received a new heart valve ...

  8. Compact expertise in valves. Planning software for all areas of water supply and sewage disposal; Armaturenwissen kompakt. Planungssoftware rund um die Wasser- und Abwasserwirtschaft

    Energy Technology Data Exchange (ETDEWEB)

    Gamper, Silke [VAG-Armaturen GmbH, Mannheim (Germany)

    2009-09-15

    Engineers, operators and users of water supply systems world-wide use the VAG UseCAD {sup registered} valve software programme for their daily work. The success story of this software began with its first release in the year 1994. Today, Version 6 of this valve planning software programme is available and the number of users increases year by year. The wide range of potential applications makes the universal VAG UseCAD {sup registered} planning program interesting to various groups of users. The software helps them to find the right valve for the intended application, to find suitable nominal diameters for specific flow rates and to plan the equipment to eliminate cavitation. (orig.)

  9. Valve Disease

    Science.gov (United States)

    ... blood. There are 4 valves in the heart: tricuspid, pulmonary, mitral, and aortic. Two types of problems can disrupt blood flow through the valves: regurgitation or stenosis. Regurgitation is also called insufficiency or incompetence. Regurgitation happens when a valve doesn’ ...

  10. Tight valve

    International Nuclear Information System (INIS)

    Guedj, F.

    1987-01-01

    This sealed valve is made with a valve seat, an axial valve with a rod fixed to its upper end, a thick bell surrounding the rod and welded by a thin join on the valve casing, a threated ring screwed onto the upper end of the rod and a magnet or electromagnet rotating the ring outside the bell [fr

  11. Check valve

    Science.gov (United States)

    Upton, H.A.; Garcia, P.

    1999-08-24

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

  12. Check valve

    International Nuclear Information System (INIS)

    Upton, H.A.; Garcia, P.

    1999-01-01

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

  13. Optimising the flow characteristic of a coke-oven flue-gas valve by means of Computational Fluid Dynamics (CFD); Stroemungsoptimierung eines Abgasventils von Koksoefen durch Computational Fluid Dynamics (CFD)

    Energy Technology Data Exchange (ETDEWEB)

    Hiller, R.; Cremer, I.; Bertling, J. [Fraunhofer-Institut fuer Umwelt-, Sicherheits- und Energietechnik UMSICHT, Oberhausen (Germany); Dittie, J.; Kim, R.; Reinke, M. [Krupp Uhde GmbH, Dortmund (Germany)

    1999-06-01

    In coke-oven operations flue-gas valves are used to switch the regenerator function from rich gas firing to lean gas firing. Compared with the simple geometry of the other parts of the flow path, which comprise flues and regenerators, the narrow and winding passages of the flue-gas valves give rise to relatively high losses in pressure. Without the construction of high (and therefore expensive) chimneys, this means that operating problems may well arise due the inadequate suction capacity. The project focused on the theoretical and experimental analysis of a coke-oven flue-gas valve. The primary aim was to reduce the pressure drop through the valve without modifying its external geomerty. The internal flow characteristics created by different valve geometries under a variety of operating conditions were simulated using the commercial CFD code Fluent/UNS, which provided velocity and pressure distributions. A half-scale model valve was constructed in order to characterise the internal flow behaviour by pressure measurement. (orig.) [Deutsch] In einem bei Fraunhofer UMSICHT durchgefuehrten Projekt wurde die Stroemung in einem Abgasventil eines Koksofens, das der Umschaltung der Regeneratorfunktion von Starkgasbeheizung auf Schwachgasbeheizung dient, theoretisch und experimentell untersucht, um die relativ hohen Druckverluste zu vermindern. Vorgeschlagen wurde eine Modifikation der Abgasventilkonstruktion, die den Druckverlust um mehr als das Zehnfache vermindert und zu einer baulichen Vereinfachung des Ventils fuehrt. (orig.)

  14. Door valve for fuel handling path

    International Nuclear Information System (INIS)

    Makishima, Katsuhiko.

    1969-01-01

    A door valve is provided which seals cover gas from a liquid metal cooled reactor without leakage therefrom. A threaded shaft is screwed into a heavy box press which is packed with lead. The shaft is adapted to be rotated by an electric motor or a manually operated wheel which is disposed outside of the door valve. From the box press a valve plate is suspended by four linkage bars, one for each corner. Each linkage bar is provided with two wheels which are respectively mounted at the connections with the box press and the valve plate. The wheels are carried on the horizontal grooves formed in a door valve casing. In operation the shaft rotates and travels to permit the box press and the valve plate to move into the door valve casing while the valve plate does not contact the casing. When the box press reaches the home position, the wheels drop into the recesses which are disposed at the ends of the grooves, the valve plate is carried on the valve opening, and the box press presses the valve plate to increase the tightness. The valve plate does not suffer wear as it does not over other parts. (Yamaguchi, T.)

  15. Valve assembly

    International Nuclear Information System (INIS)

    Sandling, M.

    1981-01-01

    An improved valve assembly, used for controlling the flow of radioactive slurry, is described. Radioactive contamination of the air during removal or replacement of the valve is prevented by sucking air from the atmosphere through a portion of the structure above the valve housing. (U.K.)

  16. Valve thrombosis following transcatheter aortic valve implantation: a systematic review.

    Science.gov (United States)

    Córdoba-Soriano, Juan G; Puri, Rishi; Amat-Santos, Ignacio; Ribeiro, Henrique B; Abdul-Jawad Altisent, Omar; del Trigo, María; Paradis, Jean-Michel; Dumont, Eric; Urena, Marina; Rodés-Cabau, Josep

    2015-03-01

    Despite the rapid global uptake of transcatheter aortic valve implantation, valve trombosis has yet to be systematically evaluated in this field. The aim of this study was to determine the clinical characteristics, diagnostic criteria, and treatment outcomes of patients diagnosed with valve thrombosis following transcatheter aortic valve implantation through a systematic review of published data. Literature published between 2002 and 2012 on valve thrombosis as a complication of transcatheter aortic valve implantation was identified through a systematic electronic search. A total of 11 publications were identified, describing 16 patients (mean age, 80 [5] years, 65% men). All but 1 patient (94%) received a balloon-expandable valve. All patients received dual antiplatelet therapy immediately following the procedure and continued to take either mono- or dual antiplatelet therapy at the time of valve thrombosis diagnosis. Valve thrombosis was diagnosed at a median of 6 months post-procedure, with progressive dyspnea being the most common symptom. A significant increase in transvalvular gradient (from 10 [4] to 40 [12] mmHg) was the most common echocardiographic feature, in addition to leaflet thickening. Thrombus was not directly visualized with echocardiography. Three patients underwent valve explantation, and the remaining received warfarin, which effectively restored the mean transvalvular gradient to baseline within 2 months. Systemic embolism was not a feature of valve thrombosis post-transcatheter aortic valve implantation. Although a rare, yet likely under-reported complication of post-transcatheter aortic valve implantation, progressive dyspnea coupled with an increasing transvalvular gradient on echocardiography within the months following the intervention likely signifies valve thrombosis. While direct thrombus visualization appears difficult, prompt initiation of oral anticoagulation therapy effectively restores baseline valve function. Copyright © 2014

  17. Series of selenoid valve pneumatic AC 220 volts with disposable contra angle as a replacement for micromotor in preclinic laboratory (experimental study on the health ministry of health polytechnic course D-III department of dental nursing Tasikmalaya

    Directory of Open Access Journals (Sweden)

    Hadiyat Miko

    2016-06-01

    Full Text Available To report on the essential performance characteristics of disposable air turbine handpiece and on aspect of their convenience and safety for preclinical use. The disposable handpiece is not recommended drilling in oral cavity. We use for student practical  in Operative Dentistry at preclinic laboratory. The other side micromotor low speed handpiece used as bur device on the phantom, the problem usually found in preclinik laboratory on practical conservation with the use of micromotor frequent damage to the handpiece (contra angel. Micromotor tend to heat up faster and have a low-speed, so it took a long time to complete the drilling, using the micromotor tend to be less safe because of the power generated from the flow of electricity at any time could damage. The price of  micromotor also is quite expensive. The limitations of the budget funds for maintenance, repair and procurement of mikromotor also became a problem. Based on these problems, the research team made a solution in the form of a replacement tool (substitute micromotor with the aim to resolve the existing problems as well as creating practices preclinic more effectively and efficiently. The use of a simple drill tool in the form of a series of Pneumatic Valve 220 volt (include electric compressor and Selenoid Disposible Handpiece Contra-angles as a new innovation in the laboratory of Dental Nursing. Majors preclinik Health Polytechnic Tasikmalaya  have been applied for last 3 years and have been able to more efficient cost of procurement tool of 70%. This disposible tool is apparently able to drill up to 20 times preparasicavity. This research uses descriptive method. Data collection techniques are used through the question form or questionnaire. Population and sample the study is a students collage 2nd years D-III of department of dental nursing Health Polytechnic Tasikmalaya. From the results of research that the majority of students expressed pleased and satisfied. This

  18. Door valve for fuel handling path

    International Nuclear Information System (INIS)

    Makishima, Katsuhiko.

    1969-01-01

    A door valve is provided which seals cover gas from a liquid metal cooled reactor without leakage therefrom. A threaded shaft is screwed into a heavy box press which is packed with lead. The shaft is adapted to be rotated by an electric motor or a manually operated wheel which is disposed outside of the door valve. A valve plate is suspended from the box press by four guide wheels mounted thereon. The guide wheels are fitted into inclined guide grooves formed at the valve plate and into grooved formed in the inner wall of a valve casing. A locking ball is provided at each side of the valve plate. In operation the shaft rotates and travels to permit the box press and the valve plate to move into the door valve casing, thus releasing the locking balls. The valve plate does not contact the bottom of the casing. When the box press reaches the home position, the valve plate is carried on the valve opening, and the box press presses the valve plate to increase the tightness. The valve plate does not suffer wear as it does not slide over other parts. (Yamaguchi, T.)

  19. Vertical pump with free floating check valve

    International Nuclear Information System (INIS)

    Lindsay, M.

    1980-01-01

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

  20. Meaning

    Science.gov (United States)

    Harteveld, Casper

    The second world to be considered concerns Meaning. In contrast to Reality and Play, this world relates to the people, disciplines, and domains that are focused on creating a certain value. For example, if this value is about providing students knowledge about physics, it involves teachers, the learning sciences, and the domains education and physics. This level goes into the aspects and criteria that designers need to take into account from this perspective. The first aspect seems obvious when we talk of “games with a serious purpose.” They have a purpose and this needs to be elaborated on, for example in terms of what “learning objectives” it attempts to achieve. The subsequent aspect is not about what is being pursued but how. To attain a value, designers have to think about a strategy that they employ. In my case this concerned looking at the learning paradigms that have come into existence in the past century and see what they have to tell us about learning. This way, their principles can be translated into a game environment. This translation involves making the strategy concrete. Or, in other words, operationalizing the plan. This is the third aspect. In this level, I will further specifically explain how I derived requirements from each of the learning paradigms, like reflection and exploration, and how they can possibly be related to games. The fourth and final aspect is the context in which the game is going to be used. It matters who uses the game and when, where, and how the game is going to be used. When designers have looked at these aspects, they have developed a “value proposal” and the worth of it may be judged by criteria, like motivation, relevance, and transfer. But before I get to this, I first go into how we human beings are meaning creators and what role assumptions, knowledge, and ambiguity have in this. I will illustrate this with some silly jokes about doctors and Mickey Mouse, and with an illusion.

  1. Mitral Valve Disease

    Science.gov (United States)

    ... for mitral valve replacement—mechanical valves (metal) or biological valves (tissue). The principal advantage of mechanical valves ... small risk of stroke due to blood clotting. Biological valves usually are made from animal tissue. Biological ...

  2. Valve system incorporating single failure protection logic

    Science.gov (United States)

    Ryan, Rodger; Timmerman, Walter J. H.

    1980-01-01

    A valve system incorporating single failure protective logic. The system consists of a valve combination or composite valve which allows actuation or de-actuation of a device such as a hydraulic cylinder or other mechanism, integral with or separate from the valve assembly, by means of three independent input signals combined in a function commonly known as two-out-of-three logic. Using the input signals as independent and redundant actuation/de-actuation signals, a single signal failure, or failure of the corresponding valve or valve set, will neither prevent the desired action, nor cause the undesired action of the mechanism.

  3. Feasibility studies of air placed techniques as emplacement means of different backfilling materials in underground radioactive waste disposal

    International Nuclear Information System (INIS)

    Atabek, R.; Conche, P.; Lajudie, A.; Revertegat, E.

    1992-01-01

    Air placed techniques are likely to be used as emplacement means of different backfilling materials in underground waste repositories. A literature survey of the air placed techniques and equipments leads to the choice of the dry process taking into account the emplacement constraints (distance: 300 m, flow: 10 m 3 /h) and the large variety of materials to be placed. Tests performed in the case of cement-based materials (with and without addition of silica fumes), for different types of cement and as a function of the incidence of the jet, show that it is possible to put in place mortars of good quality. However heterogeneity in the material composition is found when the jet is stopped. This problem may be partly solved by a better automation of the process. Complementary tests, carried out with the preselected clay of Fourges Cahaignes, clearly demonstrate the ability of the air placed technique to put in place pure clay: a dry density of 1.50kg/m 3 is reached in the case of coarse material and for a final water content of 30% (in weight). Feasibility tests performed on clay-sand mixtures are not conclusive due to an unappropriate granulometry distribution of the sand. 11 figs., 9 tabs

  4. Double-disc gate valve

    International Nuclear Information System (INIS)

    Wheatley, S.J.

    1979-01-01

    The invention relates to an improvement in a conventional double-disc gate valve having a vertically movable gate assembly including a wedge, spreaders slidably engaged therewith, a valve disc carried by the spreaders. When the gate assembly is lowered to a selected point in the valve casing, the valve discs are moved transversely outward to close inlet and outlet ports in the casing. The valve includes hold-down means for guiding the disc-and-spreader assemblies as they are moved transversely outward and inward. If such valves are operated at relatively high differential pressures, they sometimes jam during opening. Such jamming has been a problem for many years in gate valves used in gaseous diffusion plants for the separation of uranium isotopes. The invention is based on the finding that the above-mentioned jamming results when the outlet disc tilts about its horizontal axis in a certain way during opening of the valve. In accordance with the invention, tilting of the outlet disc is maintained at a tolerable value by providing the disc with a rigid downwardly extending member and by providing the casing with a stop for limiting inward arcuate movement of the member to a preselected value during opening of the valve

  5. Check valves aging assessment

    International Nuclear Information System (INIS)

    Haynes, H.D.

    1991-01-01

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

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

    International Nuclear Information System (INIS)

    Lisowski, E.; Czyżycki, W.; Rajda, J.

    2014-01-01

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

  7. 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.

  8. Safety valve including a hydraulic brake and hydraulic brake that could be fitted into a valve

    International Nuclear Information System (INIS)

    Chabat-Courrede, Jean.

    1981-01-01

    Making of a safety valve that can be fitted to a containment vessel filled with a non compressible fluid, such as the water system of a nuclear power station. It includes a hydraulic brake located between the valve and the elastic means, close to the valve which completely suppresses the high frequency oscillations of the equipment [fr

  9. Disposal of Radioactive Waste

    International Nuclear Information System (INIS)

    2011-01-01

    This Safety Requirements publication applies to the disposal of radioactive waste of all types by means of emplacement in designed disposal facilities, subject to the necessary limitations and controls being placed on the disposal of the waste and on the development, operation and closure of facilities. The classification of radioactive waste is discussed. This Safety Requirements publication establishes requirements to provide assurance of the radiation safety of the disposal of radioactive waste, in the operation of a disposal facility and especially after its closure. The fundamental safety objective is to protect people and the environment from harmful effects of ionizing radiation. This is achieved by setting requirements on the site selection and evaluation and design of a disposal facility, and on its construction, operation and closure, including organizational and regulatory requirements.

  10. Plunger with simple retention valve

    International Nuclear Information System (INIS)

    Fekete, A.V.

    1987-01-01

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

  11. 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). ...

  12. Transcatheter aortic valve replacement

    Science.gov (United States)

    ... gov/ency/article/007684.htm Transcatheter aortic valve replacement To use the sharing features on this page, please enable JavaScript. Transcatheter aortic valve replacement (TAVR) is surgery to replace the aortic valve. ...

  13. 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 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...

  14. Disposal containers for radioactive waste materials and separation systems for radioactive waste materials

    International Nuclear Information System (INIS)

    Rubin, L.S.

    1986-01-01

    A separation system for dewatering radioactive waste materials includes a disposal container, drive structure for receiving the container, and means for releasably attaching the container to the drive structure. The separation structure disposed in the container adjacent the inner surface of the side wall structure retains solids while allowing passage of liquids. The inlet port structure in the container top wall is normally closed by first valve structure that is centrifugally actuated to open the inlet port and the discharge port structure at the container periphery receives liquid that passes through the separation structure and is normally closed by a second valve structure that is centrifugally actuated to open the discharge ports. The container also includes a coupling structure for releasable engagement with the centrifugal drive structure. The centrifugal force produced when the container is driven in rotation by the drive structure opens the valve structures, and radioactive waste material introduced into the container through the open inlet port is dewatered, and the waste is compacted. The ports are automatically closed by the valves when the container drum is not subjected to centrifugal force such that containment effectiveness is enhanced and exposure of personnel to radioactive materials is minimized. (author)

  15. Leaving Moderate Tricuspid Valve Regurgitation Alone at the Time of Pulmonary Valve Replacement: A Worthwhile Approach.

    Science.gov (United States)

    Kogon, Brian; Mori, Makoto; Alsoufi, Bahaaldin; Kanter, Kirk; Oster, Matt

    2015-06-01

    Pulmonary valve disruption in patients with tetralogy of Fallot and congenital pulmonary stenosis often results in pulmonary insufficiency, right ventricular dilation, and tricuspid valve regurgitation. Management of functional tricuspid regurgitation at the time of subsequent pulmonary valve replacement remains controversial. Our aims were to (1) analyze tricuspid valve function after pulmonary valve replacement through midterm follow-up and (2) determine the benefits, if any, of concomitant tricuspid annuloplasty. Thirty-five patients with tetralogy of Fallot or congenital pulmonary stenosis were analyzed. All patients had been palliated in childhood by disrupting the pulmonary valve, and all patients had at least moderate tricuspid valve regurgitation at the time of subsequent pulmonary valve replacement. Preoperative and serial postoperative echocardiograms were analyzed. Pulmonary and tricuspid regurgitation, along with right ventricular dilation and dysfunction were scored as 0 (none), 1 (mild), 2 (moderate), and 3 (severe). Right ventricular volume and area were also calculated. Comparisons were made between patients who underwent pulmonary valve replacement alone and those who underwent concomitant tricuspid valve annuloplasty. At 1 month after pulmonary valve replacement, there were significant reductions in pulmonary valve regurgitation (mean 3 vs 0.39, p tricuspid valve regurgitation (mean 2.33 vs 1.3, p tricuspid regurgitation 1 month postoperatively between patients who underwent concomitant tricuspid annuloplasty and those who underwent pulmonary valve replacement alone (mean 1.31 vs 1.29, p = 0.81). However, at latest follow-up (mean 7.0 ± 2.8 years), the degree of tricuspid regurgitation was significantly higher in the concomitant annuloplasty group (mean 1.87 vs 1.12, p = 0.005). In patients with at least moderate tricuspid valve regurgitation, significant improvement in tricuspid valve function and right ventricular size occurs in the first

  16. What Is Heart Valve Surgery?

    Science.gov (United States)

    ... working correctly. Most valve replacements involve the aortic Tricuspid valve and mitral valves. The aortic valve separates ... where it shouldn’t. This is called incompetence, insufficiency or regurgitation. • Prolapse — mitral valve flaps don’t ...

  17. What Is Heart Valve Disease?

    Science.gov (United States)

    ... and replacing it with a man-made or biological valve. Biological valves are made from pig, cow, or human ... the valve. Man-made valves last longer than biological valves and usually don’t have to be ...

  18. Turbulence downstream of subcoronary stentless and stented aortic valves.

    Science.gov (United States)

    Funder, Jonas Amstrup; Frost, Markus Winther; Wierup, Per; Klaaborg, Kaj-Erik; Hjortdal, Vibeke; Nygaard, Hans; Hasenkam, J Michael

    2011-08-11

    Regions of turbulence downstream of bioprosthetic heart valves may cause damage to blood components, vessel wall as well as to aortic valve leaflets. Stentless aortic heart valves are known to posses several hemodynamic benefits such as larger effective orifice areas, lower aortic transvalvular pressure difference and faster left ventricular mass regression compared with their stented counterpart. Whether this is reflected by diminished turbulence formation, remains to be shown. We implanted either stented pericardial valve prostheses (Mitroflow), stentless valve prostheses (Solo or Toronto SPV) in pigs or they preserved their native valves. Following surgery, blood velocity was measured in the cross sectional area downstream of the valves using 10MHz ultrasonic probes connected to a dedicated pulsed Doppler equipment. As a measure of turbulence, Reynolds normal stress (RNS) was calculated at two different blood pressures (baseline and 50% increase). We found no difference in maximum RNS measurements between any of the investigated valve groups. The native valve had significantly lower mean RNS values than the Mitroflow (p=0.004), Toronto SPV (p=0.008) and Solo valve (p=0.02). There were no statistically significant differences between the artificial valve groups (p=0.3). The mean RNS was significantly larger when increasing blood pressure (p=0.0006). We, thus, found no advantages for the stentless aortic valves compared with stented prosthesis in terms of lower maximum or mean RNS values. Native valves have a significantly lower mean RNS value than all investigated bioprostheses. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Disposal safety

    International Nuclear Information System (INIS)

    Bartlett, J.W.

    International consensus does not seem to be necessary or appropriate for many of the issues concerned with the safety of nuclear waste disposal. International interaction on the technical aspects of disposal has been extensive, and this interaction has contributed greatly to development of a consensus technical infrastructure for disposal. This infrastructure provides a common and firm base for regulatory, political, and social actions in each nation

  20. Waste disposal

    International Nuclear Information System (INIS)

    Neerdael, B.; Marivoet, J.; Put, M.; Verstricht, J.; Van Iseghem, P.; Buyens, M.

    1998-01-01

    The primary mission of the Waste Disposal programme at the Belgian Nuclear Research Centre SCK/CEN is to propose, develop, and assess solutions for the safe disposal of radioactive waste. In Belgium, deep geological burial in clay is the primary option for the disposal of High-Level Waste and spent nuclear fuel. The main achievements during 1997 in the following domains are described: performance assessment, characterization of the geosphere, characterization of the waste, migration processes, underground infrastructure

  1. 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.

  2. Salt disposal: Paradox Basin, Utah

    International Nuclear Information System (INIS)

    1983-04-01

    This report presents the findings of a study conducted for the National Waste Terminal Storage (NWTS) Program. Permanent disposal options are examined for salt resulting from the excavation of a waste repository in the bedded salt deposits of the Paradox Basin of southeastern Utah. The study is based on a repository salt backfill compaction of 60% of the original density which leaves a total of 8 million tons of 95% pure salt to be disposed of over a 30-year period. The feasibility, impacts, and mitigation methods are examined for five options: commercial disposal, permanent onsite surface disposal, permanent offsite disposal, deepwell injection, and ocean and Great Salt Lake disposal. The study concludes the following: Commercial marketing of all repository salt would require a subsidy for transportation to major salt markets. Permanent onsite surface storage is both economically and technically feasible. Permanent offsite disposal is technically feasible but would incur additional transportation costs. Selection of an offsite location would provide a means of mitigating impacts associated with surface storage at the repository site. Deepwell injection is an attractive disposal method; however, the large water requirement, high cost of development, and poor performance of similar operating brine disposal wells eliminates this option from consideration as the primary means of disposal for the Paradox Basin. Ocean disposal is expensive because of high transportation cost. Also, regulatory approval is unlikely. Ocean disposal should be eliminated from further consideration in the Paradox Basin. Great Salt Lake disposal appears to be technically feasible. Great Salt Lake disposal would require state approval and would incur substantial costs for salt transportation. Permanent onsite disposal is the least expensive method for disposal of all repository salt

  3. Disposal Of Waste Matter

    International Nuclear Information System (INIS)

    Kim, Jeong Hyeon; Lee, Seung Mu

    1989-02-01

    This book deals with disposal of waste matter management of soiled waste matter in city with introduction, definition of waste matter, meaning of management of waste matter, management system of waste matter, current condition in the country, collect and transportation of waste matter disposal liquid waste matter, industrial waste matter like plastic, waste gas sludge, pulp and sulfuric acid, recycling technology of waste matter such as recycling system of Black clawson, Monroe and Rome.

  4. Controllable valve in a nuclear reactor system

    International Nuclear Information System (INIS)

    Schabert, H.P.; Laurer, E.

    1980-01-01

    The quick-acting gate valve of the PWR is opened and closed by means of two pistons and live steam. One of the pistons is connected to the valve disk by a piston rod which is concentrically lead into another hollow piston rod being connected to the second piston. Stops limit the strokes of the two pistons. (GL) [de

  5. 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.

  6. Rotary pneumatic valve

    Science.gov (United States)

    Hardee, Harry C.

    1991-01-01

    A rotary pneumatic valve which is thrust balanced and the pneumatic pressure developed produces only radial loads on the valve cylinder producing negligible resistance and thus minimal torque on the bearings of the valve. The valve is multiplexed such that at least two complete switching cycles occur for each revolution of the cylinder spindle.

  7. Mitral Valve Stenosis

    Science.gov (United States)

    ... the left ventricle from flowing backward. A defective heart valve fails to either open or close fully. Risk factors Mitral valve stenosis is less common today than it once was because the most common cause, ... other heart valve problems, mitral valve stenosis can strain your ...

  8. Aortic Valve Stenosis

    Science.gov (United States)

    ... most cases, doctors don't know why a heart valve fails to develop properly, so it isn't something you could have prevented. Calcium buildup on the valve. With age, heart valves may accumulate deposits of calcium (aortic valve ...

  9. 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.

  10. The development by means of trial assessments, of a procedure for radiological risk assessment of underground disposal of low and intermediate level radioactive wastes

    International Nuclear Information System (INIS)

    Thompson, B.G.J.

    1987-01-01

    Seven trials are outlined showing the development and testing of a procedure based upon pra using Monte Carlo simulators, to assess post closure risks from the underground disposal of low and intermediate level radioactive wastes. The PRA method is found to be more justifiable than the use of 'best estimates'. Problems of accounting for long-term environmental changes and of future human intrusions are discussed. The importance of achieving statistical convergence within practical time scales and resources and of accounting for the influence of different sources of systematic bias is emphasised. (orig.)

  11. Bioprosthetic Valve Fracture During Valve-in-valve TAVR: Bench to Bedside.

    Science.gov (United States)

    Saxon, John T; Allen, Keith B; Cohen, David J; Chhatriwalla, Adnan K

    2018-01-01

    Valve-in-valve (VIV) transcatheter aortic valve replacement (TAVR) has been established as a safe and effective means of treating failed surgical bioprosthetic valves (BPVs) in patients at high risk for complications related to reoperation. Patients who undergo VIV TAVR are at risk of patient-prosthesis mismatch, as the transcatheter heart valve (THV) is implanted within the ring of the existing BPV, limiting full expansion and reducing the maximum achievable effective orifice area of the THV. Importantly, patient-prosthesis mismatch and high residual transvalvular gradients are associated with reduced survival following VIV TAVR. Bioprosthetic valve fracture (BVF) is as a novel technique to address this problem. During BPV, a non-compliant valvuloplasty balloon is positioned within the BPV frame, and a highpressure balloon inflation is performed to fracture the surgical sewing ring of the BPV. This allows for further expansion of the BPV as well as the implanted THV, thus increasing the maximum effective orifice area that can be achieved after VIV TAVR. This review focuses on the current evidence base for BVF to facilitate VIV TAVR, including initial bench testing, procedural technique, clinical experience and future directions.

  12. Sub-seabed disposal of radioactive wastes

    International Nuclear Information System (INIS)

    Sivintsaev, Yu.V.

    1990-01-01

    The first stage of investigations of possibility of sub-seabed disposal of long-living intermediate-level radioactive wastes carried out by NIREX (UK) is described. Advantages and disadvantages of sub-seabed disposal of radioactive wastes are considered; regions suitable for disposal, transport means for marine disposal are described. Three types of sub-seabed burials are characterized

  13. Leakage characterization of a piloted power operated relief valve

    International Nuclear Information System (INIS)

    Ezekoye, L.I.; Hess, M.D.

    1995-01-01

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

  14. Explosive actuated valve

    International Nuclear Information System (INIS)

    Byrne, K.G.

    1983-01-01

    1. A device of the character described comprising the combination of a housing having an elongate bore and including a shoulder extending inwardly into said bore, a single elongate movable plunger disposed in said bore including an outwardly extending flange adjacent one end thereof overlying said shoulder, normally open conduit means having an inlet and an outlet perpendicularly piercing said housing intermediate said shoulder and said flange and including an intermediate portion intersecting and normally openly communicating with said bore at said shoulder, normally closed conduit means piercing said housing and intersecting said bore at a location spaced from said normally open conduit means, said elongate plunger including a shearing edge adjacent the other end thereof normally disposed intermediate both of said conduit means and overlying a portion of said normally closed conduit means, a deformable member carried by said plunger intermediate said flange and said shoulder and normally spaced from and overlying the intermediate portion of said normally open conduit means, and means on the housing communicating with the bore to retain an explosive actuator for moving said plunger to force the deformable member against the shoulder and extrude a portion of the deformable member out of said bore into portions of the normally open conduit means for plugging the same and to effect the opening of said normally closed conduit means by the plunger shearing edge substantially concomitantly with the plugging of the normally open conduit means

  15. Combination gas producing and waste-water disposal well

    Science.gov (United States)

    Malinchak, Raymond M.

    1984-01-01

    The present invention is directed to a waste-water disposal system for use in a gas recovery well penetrating a subterranean water-containing and methane gas-bearing coal formation. A cased bore hole penetrates the coal formation and extends downwardly therefrom into a further earth formation which has sufficient permeability to absorb the waste water entering the borehole from the coal formation. Pump means are disposed in the casing below the coal formation for pumping the water through a main conduit towards the water-absorbing earth formation. A barrier or water plug is disposed about the main conduit to prevent water flow through the casing except for through the main conduit. Bypass conduits disposed above the barrier communicate with the main conduit to provide an unpumped flow of water to the water-absorbing earth formation. One-way valves are in the main conduit and in the bypass conduits to provide flow of water therethrough only in the direction towards the water-absorbing earth formation.

  16. Which valve is which?

    Directory of Open Access Journals (Sweden)

    Pravin Saxena

    2015-01-01

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

  17. Waste disposal

    International Nuclear Information System (INIS)

    2005-01-01

    Radioactive waste, as a unavoidable remnant from the use of radioactive substances and nuclear technology. It is potentially hazardous to health and must therefore be managed to protect humans and the environment. The main bulk of radioactive waste must be permanently disposed in engineered repositories. Appropriate safety standards for repository design and construction are required along with the development and implementation of appropriate technologies for the design, construction, operation and closure of the waste disposal systems. As backend of the fuel cycle, resolving the issue of waste disposal is often considered as a prerequisite to the (further) development of nuclear energy programmes. Waste disposal is therefore an essential part of the waste management strategy that contributes largely to build confidence and helps decision-making when appropriately managed. The International Atomic Energy Agency provides assistance to Member States to enable safe and secure disposal of RW related to the development of national RWM strategies, including planning and long-term project management, the organisation of international peer-reviews for research and demonstration programmes, the improvement of the long-term safety of existing Near Surface Disposal facilities including capacity extension, the selection of potential candidate sites for different waste types and disposal options, the characterisation of potential host formations for waste facilities and the conduct of preliminary safety assessment, the establishment and transfer of suitable technologies for the management of RW, the development of technological solutions for some specific waste, the building of confidence through training courses, scientific visits and fellowships, the provision of training, expertise, software or hardware, and laboratory equipment, and the assessment of waste management costs and the provision of advice on cost minimisation aspects

  18. Analysis of aortic root surgery with composite mechanical aortic valve conduit and valve-sparing reconstruction.

    Science.gov (United States)

    Dias, Ricardo Ribeiro; Mejia, Omar Asdrubal Vilca; Fiorelli, Alfredo Inácio; Pomerantzeff, Pablo Maria Alberto; Dias, Altamiro Ribeiro; Mady, Charles; Stolf, Noedir Antonio Groppo

    2010-01-01

    Comparative analysis of early and late results of aortic root reconstruction with aortic valve sparing operations and the composite mechanical valve conduit replacement. From November 2002 to September 2009, 164 consecutive patients with mean age 54 ± 15 years, 115 male, underwent the aortic root reconstruction (125 mechanical valve conduit replacements and 39 valve sparing operations). Sixteen percent of patients had Marfan syndrome and 4.3% had bicuspid aortic valve. One hundred and forty-four patients (88%) were followed for a mean period of 41.1 ± 20.8 months. The hospital mortality was 4.9%, 5.6% in operations with valved conduits and 2.6% in the valve sparing procedures (P valve sparing operations, respectively (95% CI = 70% - 95%, P = 0.001), (95% CI = 82% - 95% P = 0.03) and (95% CI = 81% - 95%, P = 0.03). Multivariate analysis showed that creatinine greater than 1.4 mg/dl, Cabrol operation and renal dialysis were predictors of mortality, respectively, with occurrence chance of 6 (95% CI = 1.8 - 19.5, P = 0.003), 12 (95% CI = 3 - 49.7, P = 0.0004) and 16 (95% CI = 3.6 - 71.3, P = 0.0002). The aortic root reconstruction has a low early and late mortality, high survival free of complications and low need for reoperation. During the late follow-up, valve sparing aortic root reconstructions presented fewer incidences of bleeding, thromboembolic events and endocarditis.

  19. Transcatheter aortic valve-in-valve treatment of degenerative stentless supra-annular Freedom Solo valves: A single centre experience.

    Science.gov (United States)

    Cockburn, James; Dooley, Maureen; Parker, Jessica; Hill, Andrew; Hutchinson, Nevil; de Belder, Adam; Trivedi, Uday; Hildick-Smith, David

    2017-02-15

    Redo surgery for degenerative bioprosthetic aortic valves is associated with significant morbidity and mortality. Report results of valve-in-valve therapy (ViV-TAVI) in failed supra-annular stentless Freedom Solo (FS) bioprostheses, which are the highest risk for coronary occlusion. Six patients with FS valves (mean age 78.5 years, 50% males). Five had valvular restenosis (peak gradient 87.2 mm Hg, valve area 0.63 cm 2 ), one had severe regurgitation (AR). Median time to failure was 7 years. Patients were high risk (mean STS/Logistic EuroScore 10.6 15.8, respectively). FS valves ranged from 21 to 25 mm. Successful ViV-TAVI was achieved in 4/6 patients (67%). Of the unsuccessful cases, (patient 1 and 2 of series) patient 1 underwent BAV with simultaneous aortography which revealed left main stem occlusion. The procedure was stopped and the patient went forward for repeat surgery. Patient 2 underwent successful ViV-TAVI with a 26-mm CoreValve with a guide catheter in the left main, but on removal coronary obstruction occurred, necessitating valve snaring into the aorta. Among the successful cases, (patients 3, 4, 5, 6) the TAVIs used were CoreValve Evolut R 23 mm (n = 3), and Lotus 23 mm (n = 1). In the successful cases the peak gradient fell from 83.0 to 38.3 mm Hg. No patient was left with >1+ AR. One patient had a stroke on Day 2, with full neurological recovery. Two patients underwent semi-elective pacing for LBBB and PR >280 ms. ViV-TAVI in stentless Freedom Solo valves is high risk. The risk of coronary occlusion is high. The smallest possible prosthesis (1:1 sizing) should be used, and strategies to protect the coronary vessels must be considered. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  20. Statins for aortic valve stenosis

    Directory of Open Access Journals (Sweden)

    Luciana Thiago

    Full Text Available ABSTRACT BACKGROUND: Aortic valve stenosis is the most common type of valvular heart disease in the USA and Europe. Aortic valve stenosis is considered similar to atherosclerotic disease. Some studies have evaluated statins for aortic valve stenosis. OBJECTIVES: To evaluate the effectiveness and safety of statins in aortic valve stenosis. METHODS: Search methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL, MEDLINE, Embase, LILACS - IBECS, Web of Science and CINAHL Plus. These databases were searched from their inception to 24 November 2015. We also searched trials in registers for ongoing trials. We used no language restrictions. Selection criteria: Randomized controlled clinical trials (RCTs comparing statins alone or in association with other systemic drugs to reduce cholesterol levels versus placebo or usual care. Data collection and analysis: Primary outcomes were severity of aortic valve stenosis (evaluated by echocardiographic criteria: mean pressure gradient, valve area and aortic jet velocity, freedom from valve replacement and death from cardiovascular cause. Secondary outcomes were hospitalization for any reason, overall mortality, adverse events and patient quality of life. Two review authors independently selected trials for inclusion, extracted data and assessed the risk of bias. The GRADE methodology was employed to assess the quality of result findings and the GRADE profiler (GRADEPRO was used to import data from Review Manager 5.3 to create a 'Summary of findings' table. MAIN RESULTS: We included four RCTs with 2360 participants comparing statins (1185 participants with placebo (1175 participants. We found low-quality evidence for our primary outcome of severity of aortic valve stenosis, evaluated by mean pressure gradient (mean difference (MD -0.54, 95% confidence interval (CI -1.88 to 0.80; participants = 1935; studies = 2, valve area (MD -0.07, 95% CI -0.28 to 0.14; participants = 127; studies = 2

  1. Statins for aortic valve stenosis.

    Science.gov (United States)

    Thiago, Luciana; Tsuji, Selma Rumiko; Nyong, Jonathan; Puga, Maria Eduarda Dos Santos; Góis, Aécio Flávio Teixeira de; Macedo, Cristiane Rufino; Valente, Orsine; Atallah, Álvaro Nagib

    2016-01-01

    Aortic valve stenosis is the most common type of valvular heart disease in the USA and Europe. Aortic valve stenosis is considered similar to atherosclerotic disease. Some studies have evaluated statins for aortic valve stenosis. To evaluate the effectiveness and safety of statins in aortic valve stenosis. Search methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, LILACS - IBECS, Web of Science and CINAHL Plus. These databases were searched from their inception to 24 November 2015. We also searched trials in registers for ongoing trials. We used no language restrictions.Selection criteria: Randomized controlled clinical trials (RCTs) comparing statins alone or in association with other systemic drugs to reduce cholesterol levels versus placebo or usual care. Data collection and analysis: Primary outcomes were severity of aortic valve stenosis (evaluated by echocardiographic criteria: mean pressure gradient, valve area and aortic jet velocity), freedom from valve replacement and death from cardiovascular cause. Secondary outcomes were hospitalization for any reason, overall mortality, adverse events and patient quality of life.Two review authors independently selected trials for inclusion, extracted data and assessed the risk of bias. The GRADE methodology was employed to assess the quality of result findings and the GRADE profiler (GRADEPRO) was used to import data from Review Manager 5.3 to create a 'Summary of findings' table. We included four RCTs with 2360 participants comparing statins (1185 participants) with placebo (1175 participants). We found low-quality evidence for our primary outcome of severity of aortic valve stenosis, evaluated by mean pressure gradient (mean difference (MD) -0.54, 95% confidence interval (CI) -1.88 to 0.80; participants = 1935; studies = 2), valve area (MD -0.07, 95% CI -0.28 to 0.14; participants = 127; studies = 2), and aortic jet velocity (MD -0.06, 95% CI -0.26 to 0

  2. Annular flow diverter valve

    International Nuclear Information System (INIS)

    Rider, R.L.

    1980-01-01

    A valve is described for diverting flow from the center of two concentric tubes to the annulus between the tubes or, operating in the reverse direction, for mixing fluids from concentric tubes into a common tube and for controlling the volume ratio of said flow. It consists of a toroidal baffle disposed in sliding engagement with the interior of the inner tube downstream of a plurality of ports in the inner tube, a plurality of gates in sliding engagement with the interior of the inner tube attached to the baffle for movement therewith, a servomotor having a bullet-shaped plug on the downstream end thereof, and drive rods connecting the servomotor to the toroidal baffle. The sevomotor is adapted to move the baffle into mating engagement with the bullet-shaped plug and simultaneously move the gates away from the ports in the inner tube and to move the baffle away from the bullet-shaped plug and simultaneously move the gates to cover the ports in the inner tube

  3. Mitral Valve Prolapse

    Science.gov (United States)

    ... valve syndrome . What happens during MVP? Watch an animation of mitral valve prolapse When the heart pumps ( ... our brochures Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Heart Attack Symptoms ...

  4. Problem: Mitral Valve Regurgitation

    Science.gov (United States)

    ... each time the left ventricle contracts. Watch an animation of mitral valve regurgitation A leaking mitral valve ... Not Alone Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Heart Attack Symptoms ...

  5. Problem: Heart Valve Regurgitation

    Science.gov (United States)

    ... should be completely closed For example: Watch an animation of mitral valve regurgitation A leaking mitral valve ... Not Alone Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Heart Attack Symptoms ...

  6. Aortic valve surgery - open

    Science.gov (United States)

    ... gov/ency/article/007408.htm Aortic valve surgery - open To use the sharing features on this page, ... separates the heart and aorta. The aortic valve opens so blood can flow out. It then closes ...

  7. Corrosion of valve metals

    International Nuclear Information System (INIS)

    Draley, J.E.

    1976-01-01

    A general survey related to the corrosion of valve metals or film-forming metals. The way these metals corrode with some general examples is described. Valve metals form relatively perfect oxide films with little breakdown or leakage when anodized

  8. Mitral valve surgery - open

    Science.gov (United States)

    ... Taking warfarin (Coumadin) References Otto CM, Bonow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ... A.M. Editorial team. Heart Surgery Read more Heart Valve Diseases Read more Mitral Valve Prolapse Read more A. ...

  9. Swing check valve

    International Nuclear Information System (INIS)

    Eminger, H.E.

    1977-01-01

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

  10. Aortic valve function after bicuspidization of the unicuspid aortic valve.

    Science.gov (United States)

    Aicher, Diana; Bewarder, Moritz; Kindermann, Michael; Abdul-Khalique, Hashim; Schäfers, Hans-Joachim

    2013-05-01

    Unicuspid aortic valve (UAV) anatomy leads to dysfunction of the valve in young individuals. We introduced a reconstructive technique of bicuspidizing the UAV. Initially we copied the typical asymmetry of a normal bicuspid aortic valve (BAV) (I), later we created a symmetric BAV (II). This study compared the hemodynamic function of the two designs of a bicuspidized UAV. Aortic valve function was studied at rest and during exercise in 28 patients after repair of UAV (group I, n = 8; group II, n = 20). There were no differences among the groups I and II with respect to gender, age, body size, or weight. All patients were in New York Heart Association class I. Six healthy adults served as control individuals. All patients were studied with transthoracic echocardiography between 4 and 65 months postoperatively. Systolic gradients were assessed by continuous wave Doppler while patients were at rest and exercising on a bicycle ergometer. Aortic regurgitation was grade I or less in all patients. Resting gradients were significantly elevated in group I compared with group II and control individuals (group I, peak 33.8 ± 7.8 mm Hg; mean 19.1 ± 5.4 mm Hg; group II, peak 15.8 ± 5.4, mean 8.2 ± 2.8 mm Hg; control individuals, peak 6.0 ± 1.6, mean 3.2 ± 0.8 mm Hg; p competence. A symmetric repair design leads to improved systolic aortic valve function at rest and during exercise. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  11. Mitral Valve Prolapse

    Science.gov (United States)

    Mitral valve prolapse (MVP) occurs when one of your heart's valves doesn't work properly. The flaps of the valve are "floppy" and ... to run in families. Most of the time, MVP doesn't cause any problems. Rarely, blood can ...

  12. Fluid control valves

    International Nuclear Information System (INIS)

    Rankin, J.

    1980-01-01

    A fluid control valve is described in which it is not necessary to insert a hand or a tool into the housing to remove the valve seat. Such a valve is particularly suitable for the control of radioactive fluids since maintenance by remote control is possible. (UK)

  13. A remote control valve

    International Nuclear Information System (INIS)

    Cachard, Maurice de; Dumont, Maurice.

    1976-01-01

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

  14. 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 ...

  15. Cost effective disposal of whey

    Energy Technology Data Exchange (ETDEWEB)

    Zall, R R

    1980-01-01

    Means of reducing the problem of whey disposal are dealt with, covering inter alia the pre-treatment of cheese milk e.g., by ultrafiltration to lower the whey output, utilization of whey constituents, use of liquid whey for feeding, fermenting whey to produce methane and alcohol, and disposal of whey by irrigation of land or by purification in sewage treatment plants.

  16. Nuclear waste disposal

    International Nuclear Information System (INIS)

    Lindblom, U.; Gnirk, P.

    1982-01-01

    The subject is discussed under the following headings: the form and final disposal of nuclear wastes; the natural rock and groundwater; the disturbed rock and the groundwater; long-term behavior of the rock and the groundwater; nuclear waste leakage into the groundwater; what does it all mean. (U.K.)

  17. Integral isolation valve systems for loss of coolant accident protection

    Science.gov (United States)

    Kanuch, David J.; DiFilipo, Paul P.

    2018-03-20

    A nuclear reactor includes a nuclear reactor core comprising fissile material disposed in a reactor pressure vessel having vessel penetrations that exclusively carry flow into the nuclear reactor and at least one vessel penetration that carries flow out of the nuclear reactor. An integral isolation valve (IIV) system includes passive IIVs each comprising a check valve built into a forged flange and not including an actuator, and one or more active IIVs each comprising an active valve built into a forged flange and including an actuator. Each vessel penetration exclusively carrying flow into the nuclear reactor is protected by a passive IIV whose forged flange is directly connected to the vessel penetration. Each vessel penetration carrying flow out of the nuclear reactor is protected by an active IIV whose forged flange is directly connected to the vessel penetration. Each active valve may be a normally closed valve.

  18. Multidetector computed tomography sizing of bioprosthetic valves: guidelines for measurement and implications for valve-in-valve therapies

    International Nuclear Information System (INIS)

    Rajani, R.; Attia, R.; Condemi, F.; Webb, J.; Woodburn, P.; Hodson, D.; Nair, A.; Preston, R.; Razavi, R.; Bapat, V.N.

    2016-01-01

    Aim: To describe a technique for bioprosthetic multidetector computed tomography (MDCT) sizing and to compare MDCT-derived values against manufacturer-provided sizing. Materials and methods: Fourteen bioprosthetic stented valves commonly used in the aortic valve position were evaluated using a Philips 256 MDCT system. All valves were scanned using a dedicated cardiac CT protocol with a four-channel electrocardiography (ECG) simulator. Measurements were made of major and minor axes and the area and perimeter of the internal stent using varying reconstruction kernels and window settings. Measurements derived from MDCT (MDCT ID) were compared against the stent internal diameter (Stent ID) as provided by the valve manufacturer and the True ID (Stent ID + insertion of leaflets). All data were collected and analysed using SPSS for Mac (version 21). Results: The mean difference between the MDCT ID and Stent ID was 0.6±1.9 mm (r=0.649, p=0.012) and between MDCT ID and True ID 2.1±2 mm (r=0.71, p=0.005). There was no difference in the major (p=0.90), minor (p=0.87), area (p=0.92), or perimeter (p=0.92) measurements when sharp, standard, and detailed stent kernels were used. Similarly, the measurements remained consistent across differing windowing levels. Conclusion: Bioprosthetic stented valves may be reliably sized using MDCT in patients requiring valve-in-valve (VIV) interventions where the valve type and size are unknown. In these cases, clinicians should be aware that MDCT has a tendency to overestimate the True ID size. - Highlights: • Cardiac CT is likely to be ideally suited for bioprosthetic aortic valve sizing for valve in valve procedures. • We compared MDCT sizing for 14 varying bioprosthetic aortic valves across varying window settings and reconstruction kernels. • We provide “normal” MDCT sizing for varying valves and show their relationship to surgical sizing. • Bioprosthetic valves may be reliably sized by MDCT but require adjustment owing to

  19. Heavy gas valves

    Energy Technology Data Exchange (ETDEWEB)

    Steier, L [Vereinigte Armaturen Gesellschaft m.b.H., Mannheim (Germany, F.R.)

    1979-01-01

    Heavy gas valves must comply with special requirements. Apart from absolute safety in operation there are stringent requirements for material, sealing and ease of operation even in the most difficult conditions. Ball valves and single plate pipe gate valves lateral sealing rings have a dual, double sided sealing effect according to the GROVE sealing system. Single plate gate valves with lateral protective plates are suitable preferably for highly contaminated media. Soft sealing gate valves made of cast iron are used for low pressure applications.

  20. Reversible deep disposal

    International Nuclear Information System (INIS)

    2009-10-01

    This presentation, given by the national agency of radioactive waste management (ANDRA) at the meeting of October 8, 2009 of the high committee for the nuclear safety transparency and information (HCTISN), describes the concept of deep reversible disposal for high level/long living radioactive wastes, as considered by the ANDRA in the framework of the program law of June 28, 2006 about the sustainable management of radioactive materials and wastes. The document presents the social and political reasons of reversibility, the technical means considered (containers, disposal cavities, monitoring system, test facilities and industrial prototypes), the decisional process (progressive development and blocked off of the facility, public information and debate). (J.S.)

  1. Bentall Procedure Using Cryopreserved Valved Aortic Homografts

    Science.gov (United States)

    Christenson, Jan T.; Sierra, Jorge; Trindade, Pedro T.; Didier, Dominique; Kalangos, Afksendiyos

    2004-01-01

    The Bentall procedure is the standard operation for patients who have lesions of the ascending aorta associated with aortic valve disease. In many cases, however, mechanical prosthetic conduits are not suitable. There are few reports in the English-language medical literature concerning the mid- to long-term outcome of Bentall operations with cryopreserved homografts. Therefore, we reviewed our experience with this procedure and valved homografts. From January 1997 through December 2002, 21 patients underwent a Bentall operation with cryopreserved homografts at our institution. There were 14 males and 7 females; the mean age was 36 ± 21 years (range, 15–74 years). Eleven patients had undergone previous aortic valve surgery. All patients had aortic dilatation or aneurysms involving the ascending aorta. Indications for surgery included aortic valve stenosis or insufficiency, and aortic valve endocarditis (native valve or prosthetic). One patient had Takayasu's arteritis and 3 had Marfan syndrome. There was 1 hospital death (due to sepsis), but no other major postoperative complications. The mean hospital stay was 14 ± 7 days. Follow-up echocardiographic and computed tomographic scans were performed yearly. The mean follow-up was 34 months (6–72 months). Follow-up imaging revealed no calcifications or degenerative processes related to the homograft. Four patients had minimal valve regurgitation. Two patients died during follow-up. The 3-year actuarial survival rate was 85.7%. Our data suggest that the Bentall procedure with a valved homograft conduit is a safe procedure with excellent mid- to long-term results, comparable to results reported with aortic valve replacement with a homograft. PMID:15745290

  2. Waste Disposal

    International Nuclear Information System (INIS)

    Neerdael, B.; Marivoet, J.; Put, M.; B-Verstricht, J.; Van Iseghem, P.; Buyens, M.

    1998-01-01

    This contribution describes the main activities of the Waste and Disposal Department of the Belgian Nuclear Research Center SCK-CEN. Achievements in 1997 in three topical areas are reported on: performance assessments, waste forms/packages and near-and far field studies

  3. Relief valve testing study

    International Nuclear Information System (INIS)

    BROMM, R.D.

    2001-01-01

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

  4. 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).

  5. Heart valve replacement with the Sorin tilting-disc prosthesis. A 10-year experience.

    Science.gov (United States)

    Milano, A; Bortolotti, U; Mazzucco, A; Mossuto, E; Testolin, L; Thiene, G; Gallucci, V

    1992-02-01

    From 1978 to 1988, 697 patients with a mean age of 48 +/- 11 years (range 5 to 75 years) received a Sorin tilting-disc prosthesis; 358 had had aortic valve replacement, 247 mitral valve replacement, and 92 mitral and aortic valve replacement. Operative mortality rates were 7.8%, 11.3%, and 10.8%, respectively, in the three groups. Cumulative duration of follow-up is 1650 patient-years for aortic valve replacement (maximum follow-up 11.4 years), 963 patient-years for mitral valve replacement (maximum follow-up 9.9 years) and 328 patient-years for mitral and aortic valve replacement (maximum follow-up 9.4 years). Actuarial survival at 9 years is 72% +/- 4% after mitral valve replacement, 70% +/- 3% after aortic valve replacement, and 50% +/- 12% after mitral and aortic valve replacement, and actuarial freedom from valve-related deaths is 97% +/- 2% after mitral valve replacement, 92% +/- 2% after aortic valve replacement, and 62% +/- 15% after mitral and aortic valve replacement. Thromboembolic events occurred in 21 patients with aortic valve replacement (1.3% +/- 0.2%/pt-yr), in 12 with mitral valve replacement (1.2% +/- 0.3% pt-yr), and in seven with mitral and aortic valve replacement (2.1% +/- 0.8%), with one case of prosthetic thrombosis in each group; actuarial freedom from thromboembolism at 9 years is 92% +/- 3% after mitral valve replacement, 91% +/- 3% after aortic valve replacement, and 74% +/- 16% after mitral and aortic valve replacement. Anticoagulant-related hemorrhage was observed in 15 patients after aortic valve replacement (0.9% +/- 0.2%/pt-yr), in 9 after mitral valve replacement (0.9% +/- 0.3%/pt-yr), and in 6 with mitral and aortic valve replacement (0.9% +/- 0.5%/pt-yr); actuarial freedom from this complication at 9 years is 94% +/- 2% after aortic valve replacement, 91% +/- 4% after mitral valve replacement, and 68% +/- 16% after mitral and aortic valve replacement. Actuarial freedom from reoperation at 9 years is 97% +/- 2% after mitral and

  6. Waste disposal

    CERN Multimedia

    2006-01-01

    We should like to remind you that you can have all commonplace, conventional waste (combustible, inert, wood, etc.) disposed of by the TS-FM Group. Requests for the removal of such waste should be made by contacting FM Support on tel. 77777 or by e-mail (Fm.Support@cern.ch). For requests to be acted upon, the following information must be communicated to FM Support: budget code to be debited for the provision and removal of the skip / container. type of skip required (1m3, 4 m3, 7 m3, 15 m3, 20 m3, 30 m3). nature of the waste to be disposed of (bulky objects, cardboard boxes, etc.). building concerned. details of requestor (name, phone number, department, group, etc.). We should also like to inform you that the TS-FM Group can arrange for waste to be removed from work-sites for firms under contract to CERN, provided that the prior authorisation of the CERN Staff Member in charge of the contract is obtained and the relevant disposal/handling charges are paid. You are reminded that the selective sorting o...

  7. Waste disposal

    CERN Multimedia

    2006-01-01

    We should like to remind you that you can have all commonplace, conventional waste (combustible, inert, wood, etc.) disposed of by the TS-FM Group. Requests for the removal of such waste should be made by contacting FM Support on tel. 77777 or by e-mail (Fm.Support@cern.ch). For requests to be acted upon, the following information must be communicated to FM Support: budget code to be debited for the provision and removal of the skip / container; type of skip required (1m3, 4 m3, 7 m3, 15 m3, 20 m3, 30 m3); nature of the waste to be disposed of (bulky objects, cardboard boxes, etc.); building concerned; details of requestor (name, phone number, department, group, etc.). We should also like to inform you that the TS-FM Group can arrange for waste to be removed from work-sites for firms under contract to CERN, provided that the prior authorisation of the CERN Staff Member in charge of the contract is obtained and the relevant disposal/handling charges are paid. You are reminded that the selective sorting...

  8. Consolidation and compaction as a means to prevent settlement of bentonite/sandy silt mixes for use in waste disposal sites

    International Nuclear Information System (INIS)

    Abeele, W.V.

    1985-01-01

    The texture of the local Los Alamos tuff is that of a sandy silt with a high hydraulic conductivity. The permeability is dramatically decreased by addition of small amounts of bentonite. The coefficient of consolidation for bentonite/sandy silt ratios decreases inversely proportional with the square of that ratio, whereas the compression index, the swelling index, and the permeability change index increase with increasing bentonite ratio. A strong relationship also exists between the void ratio and the logarithm of the applied stress for any given bentonite ratio. The empirical linear relationship between the void ratio and the logarithm of the applied stress, developed by Taylor, is excellent and enables us to limit the evaluation of conductivity at any void ratio to the measurement of the initial and the desired void ratio, the initial conductivity, and the permeability change index. The decrease in void ratio caused by consolidation or natural compaction of the mixes are scrutinized. Examples of expected settlement and subsidence are calculated based on the known geotechnical characteristics of bentonite/sandy silt mixes. Remedial actions, i.e., means to limit the amount of settlement, are considered. We finally discuss our field experiment, which studies the influence of subsidence on layered systems in general and on biobarriers in particular. 15 refs., 5 tabs

  9. Guide to prosthetic cardiac valves

    International Nuclear Information System (INIS)

    Morse, D.; Steiner, R.M.; Fernandez, J.

    1985-01-01

    This book contains 10 chapters. Some of the chapter titles are: The development of artificial heart valves: Introduction and historical perspective; The radiology of prosthetic heart valves; The evaluation of patients for prosthetic valve implantation; Pathology of cardiac valve replacement; and Bioengineering of mechanical and biological heart valve substitutes

  10. Hardfacing and packings for improved valve performance

    International Nuclear Information System (INIS)

    Aikin, J.A.; Patrick, J.N.F.; Inglis, I.

    2003-01-01

    The CANDU Owners Group (COG), Chemistry, Materials and Components (CMC) Program has supported an ongoing program on valve maintenance and performance for several years. An overview is presented of recent work on iron-based hardfacing, packing qualification, friction testing of polytetrafluoroethylene (PTFE) packings, and an investigation of re-torquing valve packing. Based on this program, two new valve-packing materials have been qualified for use in CANDU stations. By doing this, CANDU maintenance can avoid having only one packing qualified for station use, as well as assess the potential impact of the industry trend towards using lower gland loads. The results from corrosion tests by AECL and the coefficient of friction studies at Battelle' s tribology testing facilities on Delcrome 910, an iron-based hardfacing alloy, indicate it is an acceptable replacement for Stellite 6 under certain conditions. This information can be used to update in-line valve purchasing specifications. The renewed interest in friction characteristics, and environmental qualification (EQ) of packing containing PTFE has resulted in a new test program in these areas. The COG-funded valve programs have resulted in modifications to design specifications for nuclear station in-line valves and have led to better maintenance practices and valve reliability. In the end, this means lower costs and cheaper electricity. (author)

  11. Factors influencing mortality after bioprosthetic valve replacement; a midterm outcome.

    Science.gov (United States)

    Javadzadegan, Hassan; Javadzadegan, Amir; Mehdizadeh Baghbani, Jafar

    2013-01-01

    Although valve repair is applied routinely nowadays, particularly for mitral regurgitation (MR) or tricuspid regurgitation (TR), valve replacement using prosthetic valves is also common especially in adults. Unfortunately the valve with ideal hemodynamic performance and long-term durability without increasing the risk of bleeding due to long-term anticoagulant therapy has not been introduced. Therefore, patients and physicians must choose either bioprosthetic or mechanical valves. Currently, there is an increasing clinical trend of using bioprosthetic valves instead of mechanical valves even in young patients apparently because of their advantages. Seventy patients undergone valvular replacement using bioprosthetic valves were evaluated by ECG and Echocardiography to assess the rhythm and ejection fracture. Mean follow-up time was 33 months (min 9, max 92). Mortality rate was 25.9% (n=18) within 8 years of follow-up. Statistical analysis showed a significant relation between atrial fibrillation rhythm and mortality (P=0.02). Morbidities occurred in 30 patients (42.8%). Significant statistical relation was found between the morbidities and age over 65 years old (P=0.005). In follow-up period, 4 cases (5.7%) underwent re-operation due to global valve dysfunction. Our study shows that using biprosthetic valve could reduce the risk of morbidity occurrence in patient who needs valve replacement. However, if medical treatments fail, patients should be referred for surgery. This would reduce the risk of mortality because of lower incident of complications such as atrial fibrillation and morbidities due to younger patients' population.

  12. Disposable products in the hospital waste stream.

    OpenAIRE

    Gilden, D. J.; Scissors, K. N.; Reuler, J. B.

    1992-01-01

    Use of disposable products in hospitals continues to increase despite limited landfill space and dwindling natural resources. We analyzed the use and disposal patterns of disposable hospital products to identify means of reducing noninfectious, nonhazardous hospital waste. In a 385-bed private teaching hospital, the 20 disposable products of which the greatest amounts (by weight) were purchased, were identified, and total hospital waste was tabulated. Samples of trash from three areas were so...

  13. Intelligent Flow Control Valve

    Science.gov (United States)

    Kelley, Anthony R (Inventor)

    2015-01-01

    The present invention is an intelligent flow control valve which may be inserted into the flow coming out of a pipe and activated to provide a method to stop, measure, and meter flow coming from the open or possibly broken pipe. The intelligent flow control valve may be used to stop the flow while repairs are made. Once repairs have been made, the valve may be removed or used as a control valve to meter the amount of flow from inside the pipe. With the addition of instrumentation, the valve may also be used as a variable area flow meter and flow controller programmed based upon flowing conditions. With robotic additions, the valve may be configured to crawl into a desired pipe location, anchor itself, and activate flow control or metering remotely.

  14. Nuclear valves latest development

    International Nuclear Information System (INIS)

    Isaac, F.; Monier, M.

    1993-01-01

    In the frame of Nuclear Power Plant upgrade (Emergency Power Supply and Emergency Core Cooling), Westinghouse had to face a new valve design philosophy specially for motor operated valves. The valves have to been designed to resist any operating conditions, postulated accident or loss of control. The requirements for motor operated valves are listed and the selected model and related upgrading explained. As part of plant upgrade and valves replacement, Westinghouse has sponsored alternative hardfacing research programme. Two types of materials have been investigated: nickel base alloys and iron base alloys. Programme requirements and test results are given. A new globe valve model (On-Off or regulating) is described developed by Alsthom Velan permitting the seat replacement in less than 10 min. (Z.S.) 2 figs

  15. Cryogenic Cam Butterfly Valve

    Science.gov (United States)

    McCormack, Kenneth J. (Inventor)

    2016-01-01

    A cryogenic cam butterfly valve has a body that includes an axially extending fluid conduit formed there through. A disc lug is connected to a back side of a valve disc and has a circular bore that receives and is larger than a cam of a cam shaft. The valve disc is rotatable for a quarter turn within the body about a lug axis that is offset from the shaft axis. Actuating the cam shaft in the closing rotational direction first causes the camming side of the cam of the cam shaft to rotate the disc lug and the valve disc a quarter turn from the open position to the closed position. Further actuating causes the camming side of the cam shaft to translate the valve disc into sealed contact with the valve seat. Opening rotational direction of the cam shaft reverses these motions.

  16. Low noise control valve

    International Nuclear Information System (INIS)

    Christie, R.S.

    1975-01-01

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

  17. Aortic or Mitral Valve Replacement With the Biocor and Biocor Supra

    Science.gov (United States)

    2017-04-26

    Aortic Valve Insufficiency; Aortic Valve Regurgitation; Aortic Valve Stenosis; Aortic Valve Incompetence; Mitral Valve Insufficiency; Mitral Valve Regurgitation; Mitral Valve Stenosis; Mitral Valve Incompetence

  18. Determination of trace metal ions via on-line separation and preconcentration by means of chelating Sepharose beads in a sequential injection lab-on-valve (SI-LOV) system coupled to electrothermal atomic absorption spectrometric detection

    DEFF Research Database (Denmark)

    Long, Xiangbao; Hansen, Elo Harald; Miró, Manuel

    2005-01-01

    The analytical performance of an on-line sequential injection lab-on-valve (SI-LOV) system using chelating Sepharose beads as sorbent material for the determination of ultra trace levels of Cd(II), Pb(II) and Ni(II) by electrothermal atomic absorption spectrometry (ETAAS) is described and discussed...

  19. Magnetic Check Valve

    Science.gov (United States)

    Morris, Brian G.; Bozeman, Richard J., Jr.

    1994-01-01

    Poppet in proposed check valve restored to closed condition by magnetic attraction instead of spring force. Oscillations suppressed, with consequent reduction of wear. Stationary magnetic disk mounted just upstream of poppet, also containing magnet. Valve body nonmagnetic. Forward pressure or flow would push poppet away from stationary magnetic disk so fluid flows easily around poppet. Stop in valve body prevents poppet from being swept away. When flow stopped or started to reverse, magnetic attraction draws poppet back to disk. Poppet then engages floating O-ring, thereby closing valve and preventing reverse flow. Floating O-ring facilitates sealing at low loads.

  20. Butterfly valves for seawater

    International Nuclear Information System (INIS)

    Yamanaka, Katsuto

    1991-01-01

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

  1. Redo mitral valve surgery

    Directory of Open Access Journals (Sweden)

    Redoy Ranjan

    2018-03-01

    Full Text Available This study is based on the findings of a single surgeon’s practice of mitral valve replacement of 167 patients from April 2005 to June 2017 who developed symptomatic mitral restenosis after closed or open mitral commisurotomy. Both clinical and color doppler echocardiographic data of peri-operative and six months follow-up period were evaluated and compared to assess the early outcome of the redo mitral valve surgery. With male-female ratio of 1: 2.2 and after a duration of 6 to 22 years symptom free interval between the redo procedures, the selected patients with mitral valve restenosis undergone valve replacement with either mechanical valve in 62% cases and also tissue valve in 38% cases. Particular emphasis was given to separate the adhered pericardium from the heart completely to ameliorate base to apex and global contraction of the heart. Besides favorable post-operative clinical outcome, the echocardiographic findings were also encouraging as there was statistically significant increase in the mitral valve area and ejection fraction with significant decrease in the left atrial diameter, pressure gradient across the mitral valve and pulmonary artery systolic pressure. Therefore, in case of inevitable mitral restenosis after closed or open commisurotomy, mitral valve replacement is a promising treatment modality.

  2. Isolation valve control device for nuclear power plant

    International Nuclear Information System (INIS)

    Yukinori, Shigeru.

    1990-01-01

    The present invention provides an isolation valve control device for detecting pipeline rupture accidents in a BWR type nuclear power plant at an early stage to close an isolation valve thereby reducing the amout of radioactivity released to the circumstance. That is, isolation valves are disposed in the pipeline for each of the systems in the nuclear power plant and flow ratemeters are disposed to at least two positions in each of the pipelines. If a meaningful difference is shown for the measured values by these flow ratemeters, the isolation valve is closed. In this way, if pipeline rupture such as leak before break (LBB) is caused to a portion of a system pipelines, the measured value from the flow ratemeters at the downstream of the pipeline is lowered. Accordingly, when a meaningful difference is formed between the value of the flow ratematers at the upstream and the downstream, occurrence of pipe rutpture between both of the flow ratemeters can be detected. As a result, the isolation valves of the system can be closed. According to the present invention, it is possible to detect the pipeline rupture at an early stage irrespective of the kind of the systems, diameter of the pipelines and the magnitude of the ruptured area, and the isolation valve can be closed. (I.S.)

  3. Experimental investigation of the fluid dynamic efficiency of a high performance multi-valve internal combustion engine during the intake phase: Influence of valve-valve interference phenomena

    Directory of Open Access Journals (Sweden)

    Algieri Angelo

    2013-01-01

    Full Text Available The purpose of the present work is the analysis of the fluid dynamic behavior of a high performance internal combustion engine during the intake phase. In particular, a four-valve spark-ignition engine has been characterized at the steady flow rig. Dimensionless discharge coefficients have been used to define the global fluid dynamic efficiency of the intake system, while the Laser Doppler Anemometry (LDA technique has been employed to evaluate the mean flow in the valve curtain area and to characterise the interference phenomena between the two intake valves. The investigation has shown the significant influence of the valve lift on the volumetric efficiency of the intake apparatus. Moreover, the experimental analysis has highlighted that the valve-valve interference phenomena have a relevant impact on the head breathability, on the flow development within the combustion chamber and on the velocity standard deviations.

  4. Drive piston assembly for a valve actuator assembly

    Science.gov (United States)

    Sun, Zongxuan

    2010-02-23

    A drive piston assembly is provided that is operable to selectively open a poppet valve. The drive piston assembly includes a cartridge defining a generally stepped bore. A drive piston is movable within the generally stepped bore and a boost sleeve is coaxially disposed with respect to the drive piston. A main fluid chamber is at least partially defined by the generally stepped bore, drive piston, and boost sleeve. First and second feedback chambers are at least partially defined by the drive piston and each are disposed at opposite ends of the drive piston. At least one of the drive piston and the boost sleeve is sufficiently configured to move within the generally stepped bore in response to fluid pressure within the main fluid chamber to selectively open the poppet valve. A valve actuator assembly and engine are also provided incorporating the disclosed drive piston assembly.

  5. Effects of valve timing, valve lift and exhaust backpressure on performance and gas exchanging of a two-stroke GDI engine with overhead valves

    International Nuclear Information System (INIS)

    Dalla Nora, Macklini; Lanzanova, Thompson Diórdinis Metzka; Zhao, Hua

    2016-01-01

    Highlights: • Two-stroke operation was achieved in a four-valve direct injection gasoline engine. • Shorter valve opening durations improved torque at lower engine speeds. • The longer the valve opening duration, the lower was the air trapping efficiency. • Higher exhaust backpressure and lower valve lift reduced the compressor work. - Abstract: The current demand for fuel efficient and lightweight powertrains, particularly for application in downsized and hybrid electric vehicles, has renewed the interest in two-stroke engines. In this framework, an overhead four-valve spark-ignition gasoline engine was modified to run in the two-stroke cycle. The scavenging process took place during a long valve overlap period around bottom dead centre at each crankshaft revolution. Boosted intake air was externally supplied at a constant pressure and gasoline was directly injected into the cylinder after valve closure. Intake and exhaust valve timings and lifts were independently varied through an electrohydraulic valve train, so their effects on engine performance and gas exchanging were investigated at 800 rpm and 2000 rpm. Different exhaust backpressures were also evaluated by means of exhaust throttling. Air trapping efficiency, charging efficiency and scavenge ratio were calculated based on air and fuel flow rates, and exhaust oxygen concentration at fuel rich conditions. The results indicated that longer intake and exhaust valve opening durations increased the charge purity and hence torque at higher engine speeds. At lower speeds, although, shorter valve opening durations increased air trapping efficiency and reduced the estimated supercharger power consumption due to lower air short-circuiting. A strong correlation was found between torque and charging efficiency, while air trapping efficiency was more associated to exhaust valve opening duration. The application of exhaust backpressure, as well as lower intake/exhaust valve lifts, made it possible to increase

  6. 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...

  7. Bioprinting a cardiac valve.

    Science.gov (United States)

    Jana, Soumen; Lerman, Amir

    2015-12-01

    Heart valve tissue engineering could be a possible solution for the limitations of mechanical and biological prostheses, which are commonly used for heart valve replacement. In tissue engineering, cells are seeded into a 3-dimensional platform, termed the scaffold, to make the engineered tissue construct. However, mimicking the mechanical and spatial heterogeneity of a heart valve structure in a fabricated scaffold with uniform cell distribution is daunting when approached conventionally. Bioprinting is an emerging technique that can produce biological products containing matrix and cells, together or separately with morphological, structural and mechanical diversity. This advance increases the possibility of fabricating the structure of a heart valve in vitro and using it as a functional tissue construct for implantation. This review describes the use of bioprinting technology in heart valve tissue engineering. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Space Vehicle Valve System

    Science.gov (United States)

    Kelley, Anthony R. (Inventor); Lindner, Jeffrey L. (Inventor)

    2014-01-01

    The present invention is a space vehicle valve system which controls the internal pressure of a space vehicle and the flow rate of purged gases at a given internal pressure and aperture site. A plurality of quasi-unique variable dimension peaked valve structures cover the purge apertures on a space vehicle. Interchangeable sheet guards configured to cover valve apertures on the peaked valve structure contain a pressure-activated surface on the inner surface. Sheet guards move outwardly from the peaked valve structure when in structural contact with a purge gas stream flowing through the apertures on the space vehicle. Changing the properties of the sheet guards changes the response of the sheet guards at a given internal pressure, providing control of the flow rate at a given aperture site.

  9. Multiple-port valve

    International Nuclear Information System (INIS)

    Doody, T.J.

    1978-01-01

    A multiple-port valve assembly is designed to direct flow from a primary conduit into any one of a plurality of secondary conduits as well as to direct a reverse flow. The valve includes two mating hemispherical sockets that rotatably receive a spherical valve plug. The valve plug is attached to the primary conduit and includes diverging passageways from that conduit to a plurality of ports. Each of the ports is alignable with one or more of a plurality of secondary conduits fitting into one of the hemispherical sockets. The other hemispherical socket includes a slot for the primary conduit such that the conduit's motion along that slot with rotation of the spherical plug about various axes will position the valve-plug ports in respect to the secondary conduits

  10. Recent improvements in check valve monitoring methods

    International Nuclear Information System (INIS)

    Haynes, H.D.

    1990-01-01

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

  11. Recent improvements in check valve monitoring methods

    International Nuclear Information System (INIS)

    Haynes, H.D.

    1991-01-01

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

  12. Durability Tests of Ball Valve Prototype with Flowmeter Operation

    Science.gov (United States)

    Rogula, J.; Romanik, G.

    2018-02-01

    The results of the investigation of the prototypical ball valve are presented in this article. The innovation of the tested valve is a ball with a built-in measuring orifice. The valve has been subjected to durability tests. Leakage under three temperatures: ambient, -30°C and +100°C was analyzed. Sealing elements of the valve were tested for roughness and deviation of shape before and after the cycles of operation. Ball valve operation means cycles of open/close. It was planned to perform 1000 cycles at each temperature condition accordingly. Tests of the valve were performed under gas pressure equal to 10 MPa. The research was carried out under the Operational Program "Intelligent Development" (POIR 01.01.01-00-0013 / 15 "Development of devices for measurement of media flow on industrial trunk-lines".

  13. Reduced-impact sliding pressure control valve for pneumatic hammer drill

    Science.gov (United States)

    Polsky, Yarom [Oak Ridge, TN; Grubelich, Mark C [Albuquerque, NM; Vaughn, Mark R [Albuquerque, NM

    2012-05-15

    A method and means of minimizing the effect of elastic valve recoil in impact applications, such as percussive drilling, where sliding spool valves used inside the percussive device are subject to poor positioning control due to elastic recoil effects experienced when the valve impacts a stroke limiting surface. The improved valve design reduces the reflected velocity of the valve by using either an energy damping material, or a valve assembly with internal damping built-in, to dissipate the compression stress wave produced during impact.

  14. Mechanical Aortic Valve Replacement in Octogenarian

    Directory of Open Access Journals (Sweden)

    Irfan Tasoglu

    2013-10-01

    Full Text Available Aim: This study analyzes the long-term outcomes of mechanical aortic valve replacement in octogenarian patients. Material and Method: A retrospective review was performed on 23 octogenarian patients who underwent mechanical aortic valve replacement. Hospital mortality, postoperative intensive care unit stay, hospital stay and long-term results was examined. Estimates of the cumulative event mortality rate were calculated by the Kaplan-Meier method. Results: The mean age of all patients was 82.9±2.3 years and most were men (65.22%. The median ejection fraction was 45%. 73.91% of patients were in New York Heart Association class III-IV. Thirteen patients (56.52% in this study underwent combined procedure, the remaining 10 (43.48% patients underwent isolated aortic valve replacement. The most common valve size was 23 mm. The mean intensive care unit stay was 1.76±1.14 days. The mean hospital stay was 9.33±5.06 days. No complications were observed in 56.52% patients during their hospital stay. The overall hospital mortality was 8.7%. Follow-up was completed for all 23 patients. Median follow-up time was 33 months (1-108 months. Actuarial survival among discharged from hospital was 59% at 5 years. Discussion: Mechanical aortic valve replacement is a safe procedure in octogenarian patients and can be performed safely even in combined procedure.

  15. Lymphangiogenesis is increased in heart valve endocarditis.

    Science.gov (United States)

    Niinimäki, Eetu; Mennander, Ari A; Paavonen, Timo; Kholová, Ivana

    2016-09-15

    Inflammation-associated lymphangiogenesis (IAL) has been identified as part of several acute and chronic inflammation. Sparse data exist on lymphatics during endocarditis. Fifty-two patients with surgically resected valves were included. Endocarditis was present in 18 aortic and 10 mitral valves. Controls consisted of 15 degenerative aortic and 9 degenerative mitral valves. There were 22 males with endocarditis and 17 males in controls. The mean age was 58 (SD 15) years with endocarditis vs. 62 (SD 13) years for controls. Lymphatics were detected by podoplanin antibody immunohistochemistry and morphometrical analysis was performed. The lymphatic density in endocarditis was 833 (SD 529) vessels/mm(2) (range 0-1707) as compared with 39 (SD 60) vessels/mm(2) (range 0-250) in controls (p=0.000). In endocarditis, the mean lymphatic size was 153 (SD 372) μm(2) ranging from 1 to 2034μm(2), whereas it was 30 (SD 29) μm(2), with maximum 90μm(2) and minimum 2μm(2) in controls (p=0.000). IAL is increased in valves with endocarditis as compared with controls. Lymphatics in heart valves may provide a novel means for treatment strategies against endocarditis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  16. Valve-sparing aortic root replacement†.

    Science.gov (United States)

    Koolbergen, David R; Manshanden, Johan S J; Bouma, Berto J; Blom, Nico A; Mulder, Barbara J M; de Mol, Bas A J M; Hazekamp, Mark G

    2015-02-01

    To evaluate our results of valve-sparing aortic root replacement and associated (multiple) valve repair. From September 2003 to September 2013, 97 patients had valve-sparing aortic root replacement procedures. Patient records and preoperative, postoperative and recent echocardiograms were reviewed. Median age was 40.3 (range: 13.4-68.6) years and 67 (69.1%) were male. Seven (7.2%) patients were younger than 18 years, the youngest being 13.4 years. Fifty-four (55.7%) had Marfan syndrome, 2 (2.1%) other fibrous tissue diseases, 15 (15.5%) bicuspid aortic valve and 3 (3.1%) had earlier Fallot repair. The reimplantation technique was used in all, with a straight vascular prosthesis in 11 (26-34 mm) and the Valsalva prosthesis in 86 (26-32 mm). Concomitant aortic valve repair was performed in 43 (44.3%), mitral valve repair in 10 (10.3%), tricuspid valve repair in 5 (5.2%) and aortic arch replacement in 3 (3.1%). Mean follow-up was 4.2 ± 2.4 years. Follow-up was complete in all. One 14-year old patient died 1.3 years post-surgery presumably of ventricular arrhythmia. One patient underwent reoperation for aneurysm of the proximal right coronary artery after 4.9 years and 4 patients required aortic valve replacement, 3 of which because of endocarditis after 0.1, 0.8 and 1.3 years and 1 because of cusp prolapse after 3.8 years. No thrombo-embolic complications occurred. Mortality, root reoperation and aortic regurgitation were absent in 88.0 ± 0.5% at 5-year follow-up. Results of valve-sparing root replacement are good, even in association with a high incidence of concomitant valve repair. Valve-sparing aortic root replacement can be performed at a very young age as long as an adult size prosthesis can be implanted. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  17. Gate valve performance prediction

    International Nuclear Information System (INIS)

    Harrison, D.H.; Damerell, P.S.; Wang, J.K.; Kalsi, M.S.; Wolfe, K.J.

    1994-01-01

    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

  18. Modeling valve leakage

    International Nuclear Information System (INIS)

    Bell, S.R.; Rohrscheib, R.

    1994-01-01

    The American Society of Mechanical Engineers (ASME) Code requires individual valve leakage testing for Category A valves. Although the U.S. Nuclear Regulatory Commission (USNRC) has recognized that it is more appropriate to test containment isolation valves in groups, as allowed by 10 CFR 50, Appendix J, a utility seeking relief from these Code requirements must provide technical justification for the relief and establish a conservative alternate acceptance criteria. In order to provide technical justification for group testing of containment isolation valves, Illinois Power developed a calculation (model) for determining the size of a leakage pathway in a valve disc or seat for a given leakage rate. The model was verified experimentally by machining leakage pathways of known size and then measuring the leakage and comparing this value to the calculated value. For the range of values typical of leakage rate testing, the correlation between the experimental values and calculated values was quote good. Based upon these results, Illinois Power established a conservative acceptance criteria for all valves in the inservice testing (IST) program and was granted relief by the USNRC from the individual leakage testing requirements of the ASME Code. This paper presents the results of Illinois Power's work in the area of valve leakage rate testing

  19. Pivot design in bileaflet valves.

    Science.gov (United States)

    Vallana, F; Rinaldi, S; Galletti, P M; Nguyen, A; Piwnica, A

    1992-01-01

    The design criteria leading to the development of a new bileaflet valve (Sorin Bicarbon) were derived from the analysis of functional requirements, the performance of existing prostheses, and the availability of an advanced carbon coating technology (Carbofilm). The hinge is the critical element affecting fluid dynamics, durability, and thrombus formation in bileaflet valves. A comparative study of three existing models led to a new hinge design that was based on coupling two spheric surfaces with different radii of curvature (leaflet pivot and hinge recess) and obtained by electroerosion into a Carbofilm-coated metallic housing. In this valve, the point of contact moves continuously by rolling, not sliding. This minimizes friction and wear and allows uninterrupted washing of the blood exposed surfaces even during diastole (a finding established in patients using transesophageal echocardiography). Tricuspid implantation without anticoagulation in 33 sheep did not lead to thrombotic events (follow-up, 40-400 days). In the first 36 clinical implants observed for 15 months (mitral position, size 29; two unrelated deaths), the mean diastolic gradient by echo Doppler was 4 +/- 1.25 mmHg; the functional area was 3.2 +/- 0.6 cm2. No leaflet fracture and no thrombotic or embolic complications were observed clinically using a standard anticoagulant regimen.

  20. Degenerative processes in bioprosthetic mitral valves in juvenile pigs

    Directory of Open Access Journals (Sweden)

    Pedersen Torben B

    2011-05-01

    Full Text Available Abstract Background Glutaraldehyde-treated bioprosthetic heart valves are commonly used for replacement of diseased heart valves. However, calcification and wear limit their durability, and the development of new and improved bioprosthetic valve designs is needed and must be evaluated in a reliable animal model. We studied glutaraldehyde-treated valves 6 months after implantation to evaluate bioprosthetic valve complications in the mitral position in juvenile pigs. Materials The study material comprised eight, 5-month old, 60-kg pigs. All pigs received a size 27, glutaraldehyde-treated, stented, Carpentier-Edwards S.A.V. mitral valve prosthesis. After six months, echocardiography was performed, and the valves explanted for gross examination, high resolution X-ray, and histological evaluation. Results Five pigs survived the follow-up period. Preexplant echocardiography revealed a median peak and mean velocity of 1.61 m/s (range: 1.17-2.00 and 1.20 (SD = ±0.25, respectively, and a median peak and mean pressure difference of 10.42 mmHg (range: 5.83-16.55 and 6.51 mmHg (SD = ±2.57, respectively. Gross examination showed minor thrombotic depositions at two commissures in two valves and at all three commissures in three valves. High resolution X-ray imaging revealed different degrees of calcification in all explanted valves, primarily in the commissural and belly areas. In all valves, histological evaluation demonstrated various degrees of fibrous sheath formation, limited immunological infiltration, and no overgrowth of host endothelium. Conclusions Bioprosthetic glutaraldehyde-treated mitral valves can be implanted into the mitral position in pigs and function after 6 months. Echocardiographic data, calcification, and histological examinations were comparable to results obtained in sheep models and human demonstrating the suitability of the porcine model.

  1. The safety relief valve handbook design and use of process safety valves to ASME and International codes and standards

    CERN Document Server

    Hellemans, Marc

    2009-01-01

    The Safety Valve Handbook is a professional reference for design, process, instrumentation, plant and maintenance engineers who work with fluid flow and transportation systems in the process industries, which covers the chemical, oil and gas, water, paper and pulp, food and bio products and energy sectors. It meets the need of engineers who have responsibilities for specifying, installing, inspecting or maintaining safety valves and flow control systems. It will also be an important reference for process safety and loss prevention engineers, environmental engineers, and plant and process designers who need to understand the operation of safety valves in a wider equipment or plant design context. . No other publication is dedicated to safety valves or to the extensive codes and standards that govern their installation and use. A single source means users save time in searching for specific information about safety valves. . The Safety Valve Handbook contains all of the vital technical and standards informat...

  2. Face-Sealing Butterfly Valve

    Science.gov (United States)

    Tervo, John N.

    1992-01-01

    Valve plate made to translate as well as rotate. Valve opened and closed by turning shaft and lever. Interactions among lever, spring, valve plate, and face seal cause plate to undergo combination of translation and rotation so valve plate clears seal during parts of opening and closing motions.

  3. Combination gas-producing and waste-water disposal well. [DOE patent application

    Science.gov (United States)

    Malinchak, R.M.

    1981-09-03

    The present invention is directed to a waste-water disposal system for use in a gas recovery well penetrating a subterranean water-containing and methane gas-bearing coal formation. A cased bore hole penetrates the coal formation and extends downwardly therefrom into a further earth formation which has sufficient permeability to absorb the waste water entering the borehole from the coal formation. Pump means are disposed in the casing below the coal formation for pumping the water through a main conduit towards the water-absorbing earth formation. A barrier or water plug is disposed about the main conduit to prevent water flow through the casing except for through the main conduit. Bypass conduits disposed above the barrier communicate with the main conduit to provide an unpumped flow of water to the water-absorbing earth formation. One-way valves are in the main conduit and in the bypass conduits to provide flow of water therethrough only in the direction towards the water-absorbing earth formation.

  4. 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.

  5. Ocean Disposal Site Monitoring

    Science.gov (United States)

    EPA is responsible for managing all designated ocean disposal sites. Surveys are conducted to identify appropriate locations for ocean disposal sites and to monitor the impacts of regulated dumping at the disposal sites.

  6. Waste disposal: preliminary studies

    International Nuclear Information System (INIS)

    Carvalho, J.F. de.

    1983-01-01

    The problem of high level radioactive waste disposal is analyzed, suggesting an alternative for the final waste disposal from irradiated fuel elements. A methodology for determining the temperature field around an underground disposal facility is presented. (E.G.) [pt

  7. Stent valve implantation in conventional redo aortic valve surgery to prevent patient-prosthesis mismatch.

    Science.gov (United States)

    Ferrari, Enrico; Franciosi, Giorgio; Clivio, Sara; Faletra, Francesco; Moccetti, Marco; Moccetti, Tiziano; Pedrazzini, Giovanni; Demertzis, Stefanos

    2017-03-01

    The goal was to show the technical details, feasibility and clinical results of balloon-expandable stent valve implantation in the aortic position during conventional redo open-heart surgery in selected obese patients with a small aortic prosthesis and severe patient-prosthesis mismatch. Two symptomatic overweight patients (body mass index of 31 and 38), each with a small aortic prosthesis (a 4-year-old, 21-mm Hancock II biological valve and a 29-year-old, 23-mm Duromedic mechanical valve), increased transvalvular gradients (59/31 and 74/44 mmHg) and a reduced indexed effective orifice area (0.50 and 0.43 cm 2 /m 2 ) underwent implantation of two 26-mm balloon-expandable Sapien 3 valves during standard on-pump redo valve surgery. Using full re-sternotomy, cardiopulmonary bypass and cardioplegic arrest, the two balloon-expandable stent valves were implanted under direct view using a standard aortotomy, after prosthesis removal and without annulus enlargement. Aortic cross-clamp times were 162 and 126 min; cardiopulmonary bypass times were 178 and 180 min; total surgical times were 360 and 318 min. At discharge, echocardiograms showed transvalvular peak and mean gradients of 13/9 and 23/13 mmHg and indexed effective orifice areas of 0.64 and 1.08 cm 2 /m 2 . The 3-month echocardiographic follow-up showed transvalvular peak and mean gradients of 18/9 and 19/11 mmHg and indexed effective orifice areas of 0.78 cm 2 /m 2 and 0.84 cm 2 /m 2 , with improved symptoms (New York Heart Association class 1). Implantation of a balloon-expandable stent valve during redo aortic valve surgery is feasible in selected cases and prevents patient-prosthesis mismatch in obese patients without need for aortic annulus enlargement. Moreover, in the case of stent valve degeneration, this approach permits additional valve-in-valve procedures with large stent valves and prevents re-redo surgery. © The Author 2016. Published by Oxford University Press on behalf of the

  8. Valve monitoring ITI-MOVATS

    International Nuclear Information System (INIS)

    Moureau, S.

    1993-01-01

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

  9. Bioprosthetic Valve Fracture to Facilitate Transcatheter Valve-in-Valve Implantation.

    Science.gov (United States)

    Allen, Keith B; Chhatriwalla, Adnan K; Cohen, David J; Saxon, John T; Aggarwal, Sanjeev; Hart, Anthony; Baron, Suzanne; Davis, J Russell; Pak, Alex F; Dvir, Danny; Borkon, A Michael

    2017-11-01

    Valve-in-valve transcatheter aortic valve replacement is less effective in small surgical bioprostheses. We evaluated the feasibility of bioprosthetic valve fracture with a high-pressure balloon to facilitate valve-in-valve transcatheter aortic valve replacement. In vitro bench testing on aortic tissue valves was performed on 19-mm and 21-mm Mitroflow (Sorin, Milan, Italy), Magna and Magna Ease (Edwards Lifesciences, Irvine, CA), Trifecta and Biocor Epic (St. Jude Medical, Minneapolis, MN), and Hancock II and Mosaic (Medtronic, Minneapolis, MN). High-pressure balloons Tru Dilation, Atlas Gold, and Dorado (C.R. Bard, Murray Hill, NJ) were used to determine which valves could be fractured and at what pressure fracture occurred. Mitroflow, Magna, Magna Ease, Mosaic, and Biocor Epic surgical valves were successfully fractured using high-pressures balloon 1 mm larger than the labeled valve size whereas Trifecta and Hancock II surgical valves could not be fractured. Only the internal valve frame was fractured, and the sewing cuff was never disrupted. Manufacturer's rated burst pressures for balloons were exceeded, with fracture pressures ranging from 8 to 24 atmospheres depending on the surgical valve. Testing further demonstrated that fracture facilitated the expansion of previously constrained, underexpanded transcatheter valves (both balloon and self-expanding) to the manufacturer's recommended size. Bench testing demonstrates that the frame of most, but not all, bioprosthetic surgical aortic valves can be fractured using high-pressure balloons. The safety of bioprosthetic valve fracture to optimize valve-in-valve transcatheter aortic valve replacement in small surgical valves requires further clinical investigation. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  10. A STUDY OF INDICATIONS, COMPLICATIONS OF PROSTHETIC VALVES AND PROGNOSIS AFTER TREATMENT OF STUCK VALVE

    Directory of Open Access Journals (Sweden)

    Y. V. Subba Reddy

    2017-03-01

    Full Text Available BACKGROUND Implantation of prosthetic cardiac valves to treat haemodynamically significant valvular diseases has become common; however, it is associated with complications. Thus, this study was intended to evaluate the indications for implantation of prosthetic valve and complications after its implantation and prognosis after treatment of one of its complication, i.e. stuck valve. MATERIALS AND METHODS This was a single-centered study wherein 50 patients who came to the emergency department with stuck valve were assessed. The 2D echocardiography was performed in all patients. Thrombolysis was done and the gradients were reassessed. Further response to treatment and development of complications before and after treatment were observed. RESULTS Of total patients, 60% were females. Mean age group was 30-40 yrs. Most of them were asymptomatic for 6 years and there was lack of compliance in 90% of patients. Most common indication for valve replacement was mitral stenosis (60% followed by mitral regurgitation (20%, aortic regurgitation and aortic stenosis (10% and combined mitral and tricuspid regurgitation (10%. Commonest valve was St. Jude (90%. Pannus was observed in 10% patients and thrombus was observed in 50% patients. Most patients had gradients 45/20 mmHg across mitral valve. In about 90% patients, gradients decreased after thrombolysis (12/5 mmHg. The complications after thrombolysis were hemiparesis (4%, death before thrombolysis (6% and death after thrombolysis (4%. CONCLUSION Considering these results, it can be concluded that prosthetic valves are seldom associated with some complications. Further, thrombolysis can be effective in patients with prosthetic valve thrombosis.

  11. Disposal Site Information Management System

    International Nuclear Information System (INIS)

    Larson, R.A.; Jouse, C.A.; Esparza, V.

    1986-01-01

    An information management system for low-level waste shipped for disposal has been developed for the Nuclear Regulatory Commission (NRC). The Disposal Site Information Management System (DSIMS) was developed to provide a user friendly computerized system, accessible through NRC on a nationwide network, for persons needing information to facilitate management decisions. This system has been developed on NOMAD VP/CSS, and the data obtained from the operators of commercial disposal sites are transferred to DSIMS semiannually. Capabilities are provided in DSIMS to allow the user to select and sort data for use in analysis and reporting low-level waste. The system also provides means for describing sources and quantities of low-level waste exceeding the limits of NRC 10 CFR Part 61 Class C. Information contained in DSIMS is intended to aid in future waste projections and economic analysis for new disposal sites

  12. Development and Characterization a Single-Active-Chamber Piezoelectric Membrane Pump with Multiple Passive Check Valves.

    Science.gov (United States)

    Zhang, Ronghui; You, Feng; Lv, Zhihan; He, Zhaocheng; Wang, Haiwei; Huang, Ling

    2016-12-12

    In order to prevent the backward flow of piezoelectric pumps, this paper presents a single-active-chamber piezoelectric membrane pump with multiple passive check valves. Under the condition of a fixed total number of passive check valves, by means of changing the inlet valves and outlet valves' configuration, the pumping characteristics in terms of flow rate and backpressure are experimentally investigated. Like the maximum flow rate and backpressure, the testing results show that the optimal frequencies are significantly affected by changes in the number inlet valves and outlet valves. The variation ratios of the maximum flow rate and the maximum backpressure are up to 66% and less than 20%, respectively. Furthermore, the piezoelectric pump generally demonstrates very similar flow rate and backpressure characteristics when the number of inlet valves in one kind of configuration is the same as that of outlet valves in another configuration. The comparison indicates that the backflow from the pumping chamber to inlet is basically the same as the backflow from the outlet to the pumping chamber. No matter whether the number of inlet valves or the number of outlet valves is increased, the backflow can be effectively reduced. In addition, the backpressure fluctuation can be significantly suppressed with an increase of either inlet valves or outlet valves. It also means that the pump can prevent the backflow more effectively at the cost of power consumption. The pump is very suitable for conditions where more accurate flow rates are needed and wear and fatigue of check valves often occur.

  13. Pulmonary valve stenosis

    Science.gov (United States)

    ... surgery - discharge Images Heart valves References Carabello BA. Valvular heart disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil ... Saunders; 2016:chap 69. Otto CM, Bownow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ...

  14. Mitral valve regurgitation

    Science.gov (United States)

    ... and dentist if you have a history of heart valve disease or congenital heart disease before treatment. Some people ... the middle Heart, front view References Carabello BA. Valvular heart disease. In: Goldman L, Schafer AI, eds. Goldman-Cecil ...

  15. Aortic Valve Disease

    Science.gov (United States)

    ... team will discuss with you the advantages and disadvantages of both valve types. Regardless of which type ... Diagnosis and Treatment Options Recovery Questions for Your Doctor Will my condition ever get better without treatment? ...

  16. Dry product valve

    International Nuclear Information System (INIS)

    Greaves, James D.

    1984-01-01

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

  17. Ball check valve

    International Nuclear Information System (INIS)

    Bevilacqua, F.

    1978-01-01

    A pressurized nuclear reactor having an instrument assembly sheathed in a metallic tube which is extended vertically upward into the reactor core by traversing a metallic guide tube which is welded to the wall of the vessel is described. Sensors in each instrument assembly are connected to instruments outside the vessel to manifest the conditions within the core. Each instrument assembly probe is moved into position within a metallic guide channel. The guide channel penetrates the wall of the vessel and forms part of the barrier to the environment within the pressure vessel. Each channel includes a ball check valve which is opened by the instrument assembly probe when the probe passes through the valve. A ball valve element is moved from its seat by the probe to a position lateral of the bore of the channel and is guided to its seat along a sloped path within the valve body when the probe is removed. 5 claims, 3 figures

  18. HLW disposal dilemma

    International Nuclear Information System (INIS)

    Andrei, V.; Glodeanu, F.

    2003-01-01

    ' strategy is now considered. There is a broad agreement that national organizations are responsible for finding their own solutions for disposal of their wastes. However, this does not mean that they have to find solutions within their own countries. This is the concept of international or multinational sheared repositories, well sited and safe facilities operated for the benefit of a number of users, with effective use of shared resources. This may be the only realistic option for some national programmes. On 22nd February 2002 a small group of organisations from 5 countries inaugurated a new association to support the concept of sharing facilities for storage and disposal of all types of long-lived radioactive wastes. The founding members are from Belgium (ONDRAF Waste Agency), Bulgaria (Kozloduy Power Plant), Hungary (PURAM Waste Agency), Japan (Obayashi Corporation) and Switzerland (Colenco Power Engineering, backed by two of the Swiss nuclear power utilities). The Association is open to all organisations sharing its goals; discussions with a range of further potential members are already underway. Romania might consider the regional disposal option. (authors)

  19. Valve for gas centrifuges

    Science.gov (United States)

    Hahs, Charles A.; Burbage, Charles H.

    1984-01-01

    The invention is a pneumatically operated valve assembly for simultaneously (1) closing gas-transfer lines connected to a gas centrifuge or the like and (2) establishing a recycle path between two of the lines so closed. The valve assembly is especially designed to be compact, fast-acting, reliable, and comparatively inexpensive. It provides large reductions in capital costs for gas-centrifuge cascades.

  20. Coanda effect in valves

    Directory of Open Access Journals (Sweden)

    Uruba Václav

    2017-01-01

    Full Text Available Coanda effect takes place in flow within valves diffuser for certain conditions. The valve plug in half-closed position forms wall-jet, which could be stable or instable, depending on geometry and other conditions. This phenomenon was subject of experimental study using time-resolved PIV technique. For the acquired data analysis the special spatio-temporal methods have been used.

  1. Leaflet escape in a new bileaflet mechanical valve: TRI technologies.

    Science.gov (United States)

    Bottio, Tomaso; Casarotto, Dino; Thiene, Gaetano; Caprili, Luca; Angelini, Annalisa; Gerosa, Gino

    2003-05-13

    Leaflet escape is a mode of structural valve failure for mechanical prostheses. This complication previously has been reported for both monoleaflet and bileaflet valve models. We report 2 leaflet escape occurrences observed in 2 patients who underwent valve replacement with a TRI Technologies valve prosthesis. At the University of Padua, between November 2000 and February 2002, 36 TRI Technologies valve prostheses (26 aortic and 10 mitral) were implanted in 34 patients (12 women and 22 men) with a mean age of 59.9+/-10.3 years (range, 30 to 75 years). There were 5 deaths: 3 in hospital, 1 early after discharge, and 1 late. Two patients experienced a catastrophic prosthetic leaflet escape; the first patient was a 52-year-old man who died 10 days after aortic valve and ascending aorta replacement, and the second was a 58-year-old man who underwent a successful emergency reoperation 20 months after mitral valve replacement. Examination of the explanted prostheses showed in both cases a leaflet escape caused by a leaflet's pivoting system fracture. Prophylactic replacement was then successfully accomplished so far in 12 patients, without evidence of structural valve failure in any of them. Among other significant postoperative complications, we observed 3 major thromboembolisms, 1 hemorrhage, and 1 paravalvular leak. These catastrophes prompted us to interrupt the implantation program, and they cast a shadow on the durability of the TRI Technologies valve prosthesis because of its high risk of structural failure.

  2. THE PROGNOSIS IN TRANSCATHETER AORTIC VALVE IMPLANTATION

    Directory of Open Access Journals (Sweden)

    T. E. Imaev

    2016-01-01

    Full Text Available Aim. To study the effect of transcatheter aortic valve implantation (TAVI, performed by different types of prostheses and various surgical access, on the prognosis of patients with critical aortic stenosis and comorbidities.Material and methods. Patients (n=130 that had consistently performed 80 TAVI by Edwards valve transfemoral (n=50 and transapical (n=30 access, as well as 50 transcatheter aortic valve replacement by CoreValve system were included into the study. Complications including perioperative mortality, total 30-day mortality, as well as post-hospital mortality were registered during aortic valve replacement, immediately after surgery, before the expiry of 30 days. Mean follow-up was 2.2 years (range 0.2 to 5.2 years.Results. Hospital mortality was on average 6.9%. 121 patients had been discharged from the department after the surgery. The number of deaths in the post-hospital period was 14.8%. Valve type and the type of access had no effect on post-hospital mortality. Men died more than 2.5 times often than women, regardless of age. Atrioventricular block, pacemaker implantation, and history of chronic obstructive pulmonary disease were the most significant prognostic factors. An important role of minor stroke and renal failure should be noted. Mortality did not depend on the surgical access or valve type. All parameters characterizing the intervention were significantly associated with mortality, both during and after surgery. The proportion of survivors at the end of the first year of observation using Corvalve system was 86.9%, Edwards valve by transfemoral access - 88% and Edwards valve by transapical access – 85.4% (insignificant differences for all groups, p>0.05. Two-year survival was 77.5%, 82.5% and 82.7%, respectively (also insignificant differences for all groups, p>0.05.Conclusion. TAVI is the method of choice, reasonable alternative approach for surgical valve replacement in patients with high surgical risk, although

  3. Peristaltic pumps for waste disposal

    International Nuclear Information System (INIS)

    Griffith, G.W.

    1992-09-01

    Laboratory robots are capable of generating large volumes of hazardous liquid wastes when they are used to perform chemical analyses of metal finishing solutions. A robot at Allied-Signal Inc., Kansas City Division, generates 30 gallons of acid waste each month. This waste contains mineral acids, heavy metals, metal fluorides, and other materials. The waste must be contained in special drums that are closed to the atmosphere. The initial disposal method was to have the robot pour the waste into a collecting funnel, which contained a liquid-sensing valve to admit the waste into the drum. Spills were inevitable, splashing occurred, and the special valve often didn't work well. The device also occupied a large amount of premium bench space. Peristaltic pumps are made to handle hazardous liquids quickly and efficiently. A variable-speed pump, equipped with a quick-loading pump head, was mounted below the robot bench near the waste barrel. The pump inlet tube was mounted above the bench within easy reach of the robot, while the outlet tube was connected directly to the barrel. During operation, the robot brings the waste liquid up to the pump inlet tube and activates the pump. When the waste has been removed, the pump stops. The procedure is quick, simple, inexpensive, safe, and reliable

  4. The disposal of radioactive waste

    International Nuclear Information System (INIS)

    Ormai, P.

    2006-01-01

    The first part shows different ways of 'producing' radioactive wastes, defines the wastes of small, medium and high activity and gives estimation on the quantity of the necessary capacities of waste disposal facilities. The modern radioactive waste disposal that is the integrated processing of the form of waste, the package, the technical facility and the embedding geological environment that guarantee the isolation together. Another factor is the lifetime of radioactive waste which means that any waste containing long lifetime waste in higher concentration than 400-4000 kBq/kg should be disposed geologically. Today the centre of debate disposal of radioactive waste is more social than technical. For this reason not only geological conditions and technical preparations, but social discussions and accepting communities are needed in selecting place of facilities. Now, the focus is on long term temporary disposal of high activity wastes, like burnt out heating elements. The final part of the paper summarizes the current Hungarian situation of disposal of radioactive wastes. (T-R.A.)

  5. Transcatheter Replacement of Failed Bioprosthetic Valves

    DEFF Research Database (Denmark)

    Simonato, Matheus; Webb, John; Kornowski, Ran

    2016-01-01

    postprocedural gradients (mean >= 20 mm Hg). Optimal implantation depths were defined by receiver operating characteristic curve. A total of 292 consecutive patients (age, 78.9 +/- 8.7 years; 60.3% male; 157 CoreValve Evolut and 135 Sapien XT) were evaluated. High implantation was associated with significantly...... lower rates of elevated gradients in comparison with low implantation (CoreValve Evolut, 15% versus 34.2%; P=0.03 and Sapien XT, 18.5% versus 43.5%; P=0.03, respectively). Optimal implantation depths were defined: CoreValve Evolut, 0 to 5 mm; Sapien XT, 0 to 2 mm (0-10% frame height); sensitivities, 91...

  6. 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....

  7. NRC valve performance test program - check valve testing

    International Nuclear Information System (INIS)

    Jeanmougin, N.M.

    1987-01-01

    The Valve Performance Test Program addresses the current requirements for testing of pressure isolation valves (PIVs) in light water reactors. Leak rate monitoring is the current method used by operating commercial power plants to survey the condition of their PIVs. ETEC testing of three check valves (4-inch, 6-inch, and 12-inch nominal diameters) indicates that leak rate testing is not a reliable method for detecting impending valve failure. Acoustic emission monitoring of check valves shows promise as a method of detecting loosened internals damage. Future efforts will focus on evaluation of acoustic emission monitoring as a technique for determining check valve condition. Three gate valves also will be tested to evaluate whether the check valve results are applicable to gate type PIVs

  8. Weak Disposability in Nonparametric Production Analysis with Undesirable Outputs

    NARCIS (Netherlands)

    Kuosmanen, T.K.

    2005-01-01

    Environmental Economics and Natural Resources Group at Wageningen University in The Netherlands Weak disposability of outputs means that firms can abate harmful emissions by decreasing the activity level. Modeling weak disposability in nonparametric production analysis has caused some confusion.

  9. Colombian experience with transcatheter aortic valve implantation of medtronic CoreValve.

    Science.gov (United States)

    Dager, Antonio E; Nuis, Rutger-Jan; Caicedo, Bernardo; Fonseca, Jaime A; Arana, Camilo; Cruz, Lidsa; Benitez, Luis M; Nader, Carlos A; Duenas, Eduardo; de Marchena, Eduardo J; O'Neill, William W; de Jaegere, Peter P

    2012-01-01

    At our institutions, increasing numbers of aortic stenosis patients were not candidates for surgical aortic valve replacement. Accordingly, we initiated the Cali Colombian Transcatheter Aortic Valve Implantation (TAVI) program. From March 2008 through January 2011, 53 consecutive patients (mean age, 79 ± 6 yr; men, 58%) underwent TAVI with the Medtronic CoreValve System, and data were prospectively collected. Our study's endpoints conformed with Valve Academic Research Consortium recommendations. We report our clinical results.Predicted mortality rates were 25% (interquartile range, 17%-34%) according to logistic EuroSCORE and 6% (interquartile range, 3%-8%) according to the Society of Thoracic Surgeons score. The 30-day mortality rate was 9% (3 intraprocedural deaths, 5 total). The combined 30-day safety endpoint was 30% (major vascular sequelae, 23%; life-threatening bleeding, 12%; myocardial infarction, 4%; major stroke, 4%; and acute kidney injury [stage 3], 2%). Eight patients (15%) required post-implantation balloon dilation and 2 (4%) required valve-in-valve implantation, for a technical device success rate of 77%. Mean peak transvalvular gradient decreased from 74 ± 29 to 17 ± 8 mmHg and mean transvalvular gradient from 40 ± 17 to 8 ± 4 mmHg (both P=0.001). Moderate or severe aortic regurgitation decreased from 32% to 18% (P=0.12) and mitral regurgitation from 32% to 13% (P=0.002). The 1-year survival rate was 81%.We found that TAVI with the CoreValve prosthesis was safe and feasible, with sustained long-term results, for treating aortic stenosis in patients at excessive surgical risk; nonetheless, serious adverse events occurred in 30% of the patients.

  10. Isolating valve, especially in main-steam pipes of power plants

    International Nuclear Information System (INIS)

    Karpenko, A.N.

    1977-01-01

    The valve for PWRs and BWRs, with diameters up to 1.25 m, for temperatures from -180 0 C to about 600 0 C and pressures up to over 50 bar, is designed for high reliability and long useful life. Two circular valve discs are moved as isolating elements in their plane across the steam direction and brought before the valve seat within a valve chamber. Shortly before reaching this final position, each disc is rotated by a small amount about its axis. Only after reaching the final position a double-wedge, further pushed forward between both discs, produces the necessary contact pressure. By revolving and frictionless closing caking together at high stresses and temperature variation is prevented and permanent tightness assured. The valve body is moved in a cylinder, cast on the valve housing, by means of a stepped piston. Its larger diameter is guided in a second cylinder flanged on above. In the cover of the second cylinder a pilot valve is mounted being controlled over 2 parallel solenoid valves by means of compressed air. In normal operation process steam from the valve chamber serves to move the stepped piston with the valve chamber. On closing of a bore, connecting both cylinder spaces, by the pilot valve the main valve is opened. If the pilot valve is opened the steam through the connecting bore is acting on both piston stages and closing the main valve. On loss of steam (pipe break) or for testing purposes one or the other cylinder space over solenoid valves is acted upon by auxiliary energy or evacuated, the main valve thus being controlled. (HP) [de

  11. Aortic valve replacement and the stentless Freedom SOLO valve

    NARCIS (Netherlands)

    Wollersheim, L.W.L.M.

    2016-01-01

    Aortic valve stenosis has become the most prevalent valvular heart disease in Europe and North America, and is generally caused by age-related calcification of the aortic valve. For most patients, severe symptomatic aortic stenosis needs effective mechanical relief in the form of valve replacement

  12. Impact of Chronic Rheumatic Valve Diseases on Large Vessels.

    Science.gov (United States)

    Altunbas, Gokhan; Yuce, Murat; Ozer, Hasan O; Davutoglu, Vedat; Ercan, Suleyman; Kizilkan, Nese; Bilici, Muhammet

    2016-01-01

    BACKGROUND AND AIM OF STUDY: Rheumatic valvular heart disease, which remains a common health problem in developing countries, has numerous consequences on the heart chambers and circulation. The study aim was to investigate the effects of chronic rheumatic valve disease on the diameters of the descending aorta (DA) and inferior vena cava (IVC). METHODS: A total of 88 patients with echocardiographically documented rheumatic valvular heart disease and 112 healthy controls were enrolled into the study. All patients underwent detailed echocardiographic examinations, while their height and body weight were recorded and adjusted to their body surface area. RESULTS: The most common involvement was mitral valve disease, followed by aortic valve disease and tricuspid valve disease. The mean diameter of the DA (indexed to BSA) was 1.79 ± 0.49 cm for patients and 1.53 ± 0.41 for controls (p Rheumatic valve disease, especially mitral stenosis, was closely related to remodeling of the great vessels.

  13. Comparative study of Butterfly valves

    International Nuclear Information System (INIS)

    Galmes Belmonte, F.B.

    1998-01-01

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

  14. A symmetric safety valve

    International Nuclear Information System (INIS)

    Burtraw, Dallas; Palmer, Karen; Kahn, Danny

    2010-01-01

    How to set policy in the presence of uncertainty has been central in debates over climate policy. Concern about costs has motivated the proposal for a cap-and-trade program for carbon dioxide, with a 'safety valve' that would mitigate against spikes in the cost of emission reductions by introducing additional emission allowances into the market when marginal costs rise above the specified allowance price level. We find two significant problems, both stemming from the asymmetry of an instrument that mitigates only against a price increase. One is that most important examples of price volatility in cap-and-trade programs have occurred not when prices spiked, but instead when allowance prices collapsed. Second, a single-sided safety valve may have unintended consequences for investment. We illustrate that a symmetric safety valve provides environmental and welfare improvements relative to the conventional one-sided approach.

  15. Evaluation of waste disposal by shale fracturing

    International Nuclear Information System (INIS)

    Weeren, H.O.

    1976-02-01

    The shale fracturing process is evaluated as a means for permanent disposal of radioactive intermediate level liquid waste generated at the Oak Ridge National Laboratory. The estimated capital operating and development costs of a proposed disposal facility are compared with equivalent estimated costs for alternative methods of waste fixation

  16. Low level waste disposal

    International Nuclear Information System (INIS)

    Barthoux, A.

    1985-01-01

    Final disposal of low level wastes has been carried out for 15 years on the shallow land disposal of the Manche in the north west of France. Final participant in the nuclear energy cycle, ANDRA has set up a new waste management system from the production center (organization of the waste collection) to the disposal site including the setting up of a transport network, the development of assessment, additional conditioning, interim storage, the management of the disposal center, records of the location and characteristics of the disposed wastes, site selection surveys for future disposals and a public information Department. 80 000 waste packages representing a volume of 20 000 m 3 are thus managed and disposed of each year on the shallow land disposal. The disposal of low level wastes is carried out according to their category and activity level: - in tumuli for very low level wastes, - in monoliths, a concrete structure, of the packaging does not provide enough protection against radioactivity [fr

  17. Nuclear reactor steam depressurization valve

    International Nuclear Information System (INIS)

    Moore, G.L.

    1991-01-01

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

  18. Comparative research on decommissioning disposal effect of two uranium mines at home and abroad

    International Nuclear Information System (INIS)

    Shi Yuke; Peng Daofeng; Liu Qingcheng

    2014-01-01

    Taking two typical decommissioned uranium mines at home and abroad for an example, disposal means and effects of two uranium mines were compared and analyzed in three aspects of waste dump disposal, mine sealing treatment, and wastewater disposal. The results showed that two uranium mines were basically identical in the disposal standards and disposal means, but the works in the source survey, wastewater disposal and long-term supervision done by oversea uranium mine were more detailed than domestic uranium mine. (authors)

  19. Valve spindle gland

    International Nuclear Information System (INIS)

    Burda, Z.; Harazim, A.; Kerlin, K.

    1979-01-01

    A gland is proposed of the valve spindle designed for radioactive or otherwise harmful media, such as in nuclear power plant primary circuits. The gland is installed in the valve cover and consists of a primary and a secondary part and of a gland case partitioning the gland space into two chambers. The bottom face of the gland case is provided with a double-sided collar for controlling the elements of the bottom primary gland while the top face is provided with a removable flange. (M.S.)

  20. 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

  1. Midterm Results of Aortic Valve Replacement with Cryopreserved Homografts

    Directory of Open Access Journals (Sweden)

    Emre Özker

    2012-06-01

    Full Text Available Objective: The aim of this study was to analyze the midterm clinical results of aortic valve replacement with cryopreserved homografts.Materials and Methods: Aortic valve replacement was performed in 40 patients with cryopreserved homograft. The indications were aortic valve endocarditis in 20 patients (50%, truncus arteriosus in 6 patients (15%, and re-stenosis or regurtitation after aortic valve reconstruction in 14 (35% patients. The valve sizes ranged from 10 to 27mm. A full root replacement technique was used for homograft replacement in all patients.Results: The 30-day postoperative mortality rate was 12.5% (5 patients. There were four late deaths. Only one of them was related to cardiac events. Overall mortality was 22.5%. Thirty-three patients were followed up for 67±26 months. Two patients needed reoperation due to aortic aneurysm caused by endocarditis. The mean transvalvular gradient significantly decreased after valve replacement (p<0.003. The last follow up showed that the 27 (82% patients had a normal left ventricular function.Conclusion: Cryopreserved homografts are safe alternatives to mechanical valves that can be used when there are proper indications. Although it has a high perioperative mortality rate, cryopreserved homograft implantation is an alternative for valve replacement, particularly in younger patients and for complex surgical problems such as endocarditis that must be minimalized.

  2. Cavitation problems in sodium valves

    International Nuclear Information System (INIS)

    Elie, X.

    1976-01-01

    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)

  3. Transcatheter aortic valve implantation in failed bioprosthetic surgical valves

    DEFF Research Database (Denmark)

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

    2014-01-01

    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......, stroke, and New York Heart Association functional class. RESULTS: Modes of bioprosthesis failure were stenosis (n = 181 [39.4%]), regurgitation (n = 139 [30.3%]), and combined (n = 139 [30.3%]). The stenosis group had a higher percentage of small valves (37% vs 20.9% and 26.6% in the regurgitation...... and combined groups, respectively; P = .005). Within 1 month following valve-in-valve implantation, 35 (7.6%) patients died, 8 (1.7%) had major stroke, and 313 (92.6%) of surviving patients had good functional status (New York Heart Association class I/II). The overall 1-year Kaplan-Meier survival rate was 83...

  4. Assessment of structural valve deterioration of transcatheter aortic bioprosthetic balloon-expandable valves using the new European consensus definition.

    Science.gov (United States)

    Eltchaninoff, Hélène; Durand, Eric; Avinée, Guillaume; Tron, Christophe; Litzler, Pierre-Yves; Bauer, Fabrice; Dacher, Jean-Nicolas; Werhlin, Camille; Bouhzam, Najime; Bettinger, Nicolas; Candolfi, Pascal; Cribier, Alain

    2018-03-30

    Durability of transcatheter aortic bioprosthetic valves remains a major issue. Standardised definitions of deterioration and failure of bioprosthetic valves have recently been proposed. The aim of this study was to assess structural transcatheter valve deterioration (SVD) and bioprosthetic valve failure (BVF) using these new definitions. All TAVI patients implanted up to September 2012 with a minimal theoretical five-year follow-up were included. Systematic clinical and echocardiographic follow-up was performed annually. New standardised definitions were used to assess durability of transcatheter aortic bioprosthetic valves. From 2002 to 2012, 378 patients were included. Mean age and logistic EuroSCORE were 83.3±6.8 years and 22.8±13.1%. Thirty-day mortality was 13.2%. Nine patients had SVD including two severe forms and two patients had definite late BVF. The incidence of SVD and BVF at eight years was 3.2% (95% CI: 1.45-6.11) and 0.58% (95% CI: 0.15-2.75), respectively. Even though limited by the poor survival of the very high-risk/compassionate early population, our data do not demonstrate any alarm concerning transcatheter aortic valve durability. Careful prospective assessment in younger and lower-risk patients and comparison with surgical bioprosthetic valves are required for further assessment of the long-term durability of transcatheter valves.

  5. 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 r...

  6. Heart valve surgery - discharge

    Science.gov (United States)

    ... ACC guideline for the management of patients with valvular heart disease: executive summary: a report of the American College ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Browse the Encyclopedia A.D.A.M., Inc. ...

  7. Poppet valve tester

    Science.gov (United States)

    Tellier, G. F.

    1973-01-01

    Tester investigates fundamental factors affecting cyclic life and sealing performance of valve seats and poppets. Tester provides for varying impact loading of poppet against seat and rate of cycling, and controls amount and type of relative motion between sealing faces of seat and poppet. Relative motion between seat and poppet can be varied in three modes.

  8. Thermostatic Radiator Valve Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Dentz, Jordan [Advanced Residential Integrated Energy Solutions Collaborative, New York, NY (United States); Ansanelli, Eric [Advanced Residential Integrated Energy Solutions Collaborative, 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.

  9. Blocked Urethral Valves

    Science.gov (United States)

    ... if any damage has occurred to the upper urinary tract. Your pediatrician will consult with a pediatric nephrologist (kidney specialist) or nurologist, who may recommend surgery to remove the obstructing valves and prevent further infection or damage to the kidneys or urinary system. ...

  10. Treated Effluent Disposal Facility

    Data.gov (United States)

    Federal Laboratory Consortium — Treated non-hazardous and non-radioactive liquid wastes are collected and then disposed of through the systems at the Treated Effluent Disposal Facility (TEDF). More...

  11. Geoenvironment and waste disposal

    International Nuclear Information System (INIS)

    1983-07-01

    Within the activities planned by UNESCO in its Water and Earth Science programme, an interdisciplinary meeting on geology and environment was scheduled by this organization to be held by the beginning of 1983. At this meeting it was intended to consider geological processes in the light of their interaction and influence on the environment with special emphasis on the impact of various means of waste disposal on geological environment and on man-induced changes in the geological environment by mining, human settlements, etc. Considering the increasing interest shown by the IAEA in the field, through environmental studies, site studies, and impact studies for nuclear facilities and particularly nuclear waste disposal, UNESCO expressed the wish to organize the meeting jointly so as to take into account the experience gained by the Agency, and in order to avoid any duplication in the activities of the two organizations. This request was agreed to by the IAEA Secretariat and as a result, the meeting was organized by both organizations and held at IAEA Headquarters in Vienna from 21-23 March 1983. The report of this meeting is herewith presented

  12. Unicuspid aortic valve disease: a magnetic resonance imaging study

    International Nuclear Information System (INIS)

    Debl, K.; Buchner, S.; Heinicke, N.; Riegger, G.; Luchner, A.; Djavidani, B.; Poschenrieder, F.; Feuerbach, S.; Schmid, C.; Kobuch, R.

    2008-01-01

    Purpose: congenitally malformed aortic valves are a common finding in adults with aortic valve disease. Most of these patients have bicuspid aortic valve disease. Unicuspid aortic valve disease (UAV) is rare. The aim of our study was to describe valve morphology and the dimensions of the proximal aorta in a cohort of 12 patients with UAV in comparison to tricuspid aortic valve disease (TAV) using magnetic resonance imaging (MRI). Materials and methods/results: MRI studies were performed on a 1.5 T scanner in a total of 288 consecutive patients with aortic valve disease. 12 aortic valves were retrospectively classified as UAV. Annulus areas and dimensions of the thoracic aorta were retrospectively compared to a cohort of 103 patients with TAV. In UAV, valve morphology was unicuspid unicommissural with a posterior commissure in all patients. Mean annulus areas and mean diameters of the ascending aorta were significantly greater in UAV compared to TAV (12.6 ± 4.7 cm 2 vs. 8.7 ± 2.3 cm 2 , p < 0.01 and 4.6 ± 0.7 cm vs. 3.6 ± 0.5 cm, p < 0.0001, respectively), while no differences were observed in the mean diameters of the aortic arch (2.3 ± 0.6 cm vs. 2.3 ± 0.4 cm, p = 0.69). The diameters of the descending aorta were slightly smaller in UAV compared to TAV (2.2 ± 0.5 cm vs. 2.6 ± 0.3 cm, p < 0.05). (orig.)

  13. Unicuspid aortic valve disease: a magnetic resonance imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Debl, K.; Buchner, S.; Heinicke, N.; Riegger, G.; Luchner, A. [Klinik und Poliklinik fuer Innere Medizin II, Universitaetsklinikum Regensburg (Germany); Djavidani, B.; Poschenrieder, F.; Feuerbach, S. [Inst. fuer Roentgendiagnostik, Universitaetsklinikum Regensburg (Germany); Schmid, C.; Kobuch, R. [Klinik und Poliklinik fuer Herz-, Thorax- und herznahe Gefaesschirurgie, Universitaetsklinikum Regensburg (Germany)

    2008-11-15

    Purpose: congenitally malformed aortic valves are a common finding in adults with aortic valve disease. Most of these patients have bicuspid aortic valve disease. Unicuspid aortic valve disease (UAV) is rare. The aim of our study was to describe valve morphology and the dimensions of the proximal aorta in a cohort of 12 patients with UAV in comparison to tricuspid aortic valve disease (TAV) using magnetic resonance imaging (MRI). Materials and methods/results: MRI studies were performed on a 1.5 T scanner in a total of 288 consecutive patients with aortic valve disease. 12 aortic valves were retrospectively classified as UAV. Annulus areas and dimensions of the thoracic aorta were retrospectively compared to a cohort of 103 patients with TAV. In UAV, valve morphology was unicuspid unicommissural with a posterior commissure in all patients. Mean annulus areas and mean diameters of the ascending aorta were significantly greater in UAV compared to TAV (12.6 {+-} 4.7 cm{sup 2} vs. 8.7 {+-} 2.3 cm{sup 2}, p < 0.01 and 4.6 {+-} 0.7 cm vs. 3.6 {+-} 0.5 cm, p < 0.0001, respectively), while no differences were observed in the mean diameters of the aortic arch (2.3 {+-} 0.6 cm vs. 2.3 {+-} 0.4 cm, p = 0.69). The diameters of the descending aorta were slightly smaller in UAV compared to TAV (2.2 {+-} 0.5 cm vs. 2.6 {+-} 0.3 cm, p < 0.05). (orig.)

  14. Tricuspid valve endocarditis

    Science.gov (United States)

    Hussain, Syed T.; Witten, James; Shrestha, Nabin K.; Blackstone, Eugene H.

    2017-01-01

    Right-sided infective endocarditis (RSIE) is less common than left-sided infective endocarditis (IE), encompassing only 5–10% of cases of IE. Ninety percent of RSIE involves the tricuspid valve (TV). Given the relatively small numbers of TVIE cases operated on at most institutions, the purpose of this review is to highlight and discuss the current understanding of IE involving the TV. RSIE and TVIE are strongly associated with intravenous drug use (IVDU), although pacemaker leads, defibrillator leads and vascular access for dialysis are also major risk factors. Staphylococcus aureus is the predominant causative organism in TVIE. Most patients with TVIE are successfully treated with antibiotics, however, 5–16% of RSIE cases eventually require surgical intervention. Indications and timing for surgery are less clear than for left-sided IE; surgery is primarily considered for failed medical therapy, large vegetations and septic pulmonary embolism, and less often for TV regurgitation and heart failure. Most patients with an infected prosthetic TV will require surgery. Concomitant left-sided IE has its own surgical indications. Earlier surgical intervention may potentially prevent further destruction of leaflet tissue and increase the likelihood of TV repair. Fortunately, TV debridement and repair can be accomplished in most cases, even those with extensive valve destruction, using a variety of techniques. Valve repair is advocated over replacement, particularly in IVDUs patients who are young, non-compliant and have a higher risk of recurrent infection and reoperation with valve replacement. Excising the valve without replacing, it is not advocated; it has been reported previously, but these patients are likely to be symptomatic, particularly in cases with septic pulmonary embolism and increased pulmonary vascular resistance. Patients with concomitant left-sided involvement have worse prognosis than those with RSIE alone, due predominantly to greater likelihood of

  15. Regression in left ventricular mass after aortic valve replacement for chronic aortic regurgitation is unrelated to prosthetic valve size.

    Science.gov (United States)

    Brown, Morgan L; Schaff, Hartzell V; Suri, Rakesh M; Li, Zhuo; Sundt, Thoralf M; Dearani, Joseph A; Enriquez-Sarano, Maurice

    2011-08-01

    We examined the role of prosthesis-patient mismatch on left ventricular mass regression after aortic valve replacement for chronic aortic valve regurgitation. We selected patients who had complete preoperative and follow-up echocardiograms with measurement of left ventricular mass. Patients were excluded who had moderate or greater aortic valve stenosis, concomitant coronary artery bypass grafting, or mitral valve procedures. Patients' mean age was 55 ± 17 years; 21% were female. The mean preoperative indexed left ventricular mass was 150 ± 45 g/m(2). Patients with mildly (n = 44; mean indexed mass, 126 ± 15 g/m(2)), moderately (n = 31; mean indexed mass, 168 ± 11 g/m(2)), or severely (n = 15; mean indexed mass, 241 ± 34 g/m(2)) increased preoperative indexed left ventricular mass, were similar, except for lower ejection fractions, larger end-diastolic dimensions, and larger ventricular wall thicknesses in the severely enlarged group (P regression was unrelated to labeled valve size, prosthesis-patient mismatch, or measured indexed effective aortic valve area. A greater preoperative indexed left ventricular mass (P regression. Despite having greater left ventricular mass regression, patients with severe preoperative indexed left ventricular mass did not return to normal values (mean, 142 ± 25 g/m(2)). Left ventricular mass regression after aortic valve replacement for chronic aortic regurgitation is unrelated to indexed prosthetic valve area. Although incomplete, regression is greatest in patients with the largest preoperative indexed left ventricular mass. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-07-01

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

  17. Flow mapping for assessment of native and repaired valves

    International Nuclear Information System (INIS)

    Felner, J.; Pollack, S.; McMillan, S.; Yoganathan, A.; Knopf, W.; Craver, J.

    1986-01-01

    Color Doppler flow mapping (CDFM) was performed in 47 normal women ages 18-41 mean (m) 28 to determine the normal flow phenomena across each of the 4 heart valves. The group included: 15 elite marathon runners average run (ave.) 70 miles/week, heart rate (HR) 35-54 (m 45); 14 joggers ave. 40 mi/wkm HR 40-69 (m 53); and 17 controls 0 mi/wk, HR 49-93 (m 77). 2-D echo and CDFM defined the motion of each valve, including the presence of mitral valve prolapse (MVP), the ventricular inflow and outflow patterns and the presence of regurgitation

  18. Plastik på trikuspidalklappen (Tricuspid valve annuloplasty. The neglected valve)

    DEFF Research Database (Denmark)

    Pedersen, Thais A L; Wierup, Per; Pedersen, Lia Mendes

    2010-01-01

    INTRODUCTION: Tricuspid valve regurgitation (TVR) is often secondary to left-sided or congenital heart disease (CHD). Surgical correction of TVR is indicated when the primary abnormalities require operation. MATERIAL AND METHODS: Retrospective analysis of all 50 patients (mean age: 65 years (rang...

  19. 12 CFR 41.83 - Disposal of consumer information.

    Science.gov (United States)

    2010-01-01

    ... Duties of Users of Consumer Reports Regarding Address Discrepancies and Records Disposal § 41.83 Disposal of consumer information. (a) Definitions as used in this section. (1) Bank means national banks... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Disposal of consumer information. 41.83 Section...

  20. Topology Selection and Analysis of Actuator for Seat Valves suitable for use in Digital Displacement Pumps/Motors

    DEFF Research Database (Denmark)

    Rømer, Daniel; Johansen, Per; Pedersen, Henrik C.

    2013-01-01

    seat valves is developed, and the resulting dynamic response of the seat valve is presented. Requirements for the valve actuator is established based on the DD application, and three feasible actuator topologies are analyzed by means of transient electro-magnetic FEA simulation. From this analysis...

  1. Pulmonary valve endocarditis associated to a septal interventricular defect and infundibular and pulmonary valve Stenosis

    International Nuclear Information System (INIS)

    Echeverri, Juan G; Diaz, Alejandro; Jaramillo, Nicolas; Gonzalez, Sergio

    2004-01-01

    Ventricular septal defects generate 10% of all adult congenital cardiopathies. 4% to 8% of patients to whom the defect has not been corrected are in risk of developing endocarditis. Pulmonary valve endocarditis is a rare event (1.5% to 2% of all endocarditis cases) and its mean etiology is intravenous drug abuse. The most frequently isolated microorganism in these cases is staphylococcus aurous. We report a case of pulmonary valve endocarditis associated with ventricular septal defect and valvular and infundibular pulmonary stenosis caused by streptococcus sp. in a patient without past medical history of drug abuse, alcoholism or previous invasive procedures

  2. Experimental investigation of the check valve behaviour when the flow is reversing

    Directory of Open Access Journals (Sweden)

    Himr D.

    2017-01-01

    Full Text Available Check valve in a pipeline is supposed to prevent the reverse flow and to allow the flow in the positive direction. The construction of check valves follows these requirements, but the check valve must not cause pressure pulsations in transients. It means when the fluid is accelerating or decelerating. The article describes an experimental investigation of a swing check valve when the flow is changing its direction. The check valve was placed in an experimental circuit, where the pressure on the upstream and downstream side of the valve was measured and the current value of flow rate was determined. The goal was to simulate conditions in the real system, where the check valve slam had been observed.

  3. Valve Concepts for Microfluidic Cell Handling

    Directory of Open Access Journals (Sweden)

    M. Grabowski

    2010-01-01

    Full Text Available In this paper we present various pneumatically actuated microfluidic valves to enable user-defined fluid management within a microfluidic chip. To identify a feasible valve design, certain valve concepts are simulated in ANSYS to investigate the pressure dependent opening and closing characteristics of each design. The results are verified in a series of tests. Both the microfluidic layer and the pneumatic layer are realized by means of soft-lithographic techniques. In this way, a network of channels is fabricated in photoresist as a molding master. By casting these masters with PDMS (polydimethylsiloxane we get polymeric replicas containing the channel network. After a plasma-enhanced bonding process, the two layers are irreversibly bonded to each other. The bonding is tight for pressures up to 2 bar. The valves are integrated into a microfluidic cell handling system that is designed to manipulate cells in the presence of a liquid reagent (e.g. PEG – polyethylene glycol, for cell fusion. For this purpose a user-defined fluid management system is developed. The first test series with human cell lines show that the microfluidic chip is suitable for accumulating cells within a reaction chamber, where they can be flushed by a liquid medium.

  4. Cyclonic valve test: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, Andre Sampaio; Moraes, Carlos Alberto C.; Marins, Luiz Philipe M.; Soares, Fabricio; Oliveira, Dennis; Lima, Fabio Soares de; Airao, Vinicius [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil); Ton, Tijmen [Twister BV, Rijswijk (Netherlands)

    2012-07-01

    For many years, the petroleum industry has been developing a valve that input less shear to the flow for a given required pressure drop and this can be done using the cyclonic concept. This paper presents a comparison between the performances of a cyclonic valve (low shear) and a conventional globe valve. The aim of this work is to show the advantages of using a cyclonic low shear valve instead of the commonly used in the primary separation process by PETROBRAS. Tests were performed at PETROBRAS Experimental Center (NUEX) in Aracaju/SE varying some parameters: water cut; pressure loss (from 4 kgf/cm2 to 10 kgf/cm2); flow rates (30 m3/h and 45 m3/h). Results indicates a better performance of the cyclonic valve, if compared with a conventional one, and also that the difference of the performance, is a function of several parameters (emulsion stability, water content free, and oil properties). The cyclonic valve tested can be applied as a choke valve, as a valve between separation stages (for pressure drop), or for controlling the level of vessels. We must emphasize the importance to avoid the high shear imposed by conventional valves, because once the emulsion is created, it becomes more difficult to break it. New tests are being planned to occur in 2012, but PETROBRAS is also analyzing real cases where the applications could increase the primary process efficiency. In the same way, the future installations are also being designed considering the cyclonic valve usage. (author)

  5. Crushing leads to waste disposal savings for FUSRAP

    Energy Technology Data Exchange (ETDEWEB)

    Darby, J. [Department of Energy, Oak Ridge, TN (United States)

    1997-02-01

    In this article the author discusses the application of a rock crusher as a means of implementing cost savings in the remediation of FUSRAP sites. Transportation and offsite disposal costs are at present the biggest cost items in the remediation of FUSRAP sites. If these debris disposal problems can be handled in different manners, then remediation savings are available. Crushing can result in the ability to handle some wastes as soil disposal problems, which have different disposal regulations, thereby permitting cost savings.

  6. Aortic valve-sparing surgery in Marfan syndrome.

    Science.gov (United States)

    Nachum, Eyal; Shinfeld, Amichay; Kogan, Alexander; Preisman, Sergey; Levin, Shany; Raanani, Ehud

    2013-08-01

    Patients with Marfan syndrome are referred for cardiac surgery due to root aneurysm with or without aortic valve regurgitation. Because these patients are young and frequently present with normal-appearing aortic cusps, valve sparing is often recommended. However, due to the genetic nature of the disease, the durability of such surgery remains uncertain. Between February 2004 and June 2012, 100 patients in our department suffering from aortic aneurysm with aortic valve regurgitation underwent elective aortic valve-sparing surgery. Of them, 30 had Marfan syndrome, were significantly younger (30 +/- 13 vs. 53 +/- 16 years), and had a higher percentage of root aneurysm, compared with ascending aorta aneurysm in their non-Marfan counterparts. We evaluated the safety, durability, clinical and echocardiographic mid-term results of these patients. While no early deaths were reported in either group, there were a few major early complications in both groups. At follow-up (reaching 8 years with a mean of 34 +/- 26 months) there were no late deaths, and few major late complications in the Marfan group. Altogether, 96% and 78% of the patients were in New York Heart Association functional class I-II in the Marfan and non-Marfan groups respectively. None of the Marfan patients needed reoperation on the aortic valve. Freedom from recurrent aortic valve regurgitation > 3+ was 94% in the Marfan patients. Aortic valve-sparing surgery in Marfan symdrome patients is safe and yields good mid-term clinical outcomes.

  7. Prior oral conditions in patients undergoing heart valve surgery.

    Science.gov (United States)

    Silvestre, Francisco-Javier; Gil-Raga, Irene; Martinez-Herrera, Mayte; Lauritano, Dorina; Silvestre-Rangil, Javier

    2017-11-01

    Patients scheduled for heart valve surgery should be free of any oral infectious disorders that might pose a risk in the postoperative period. Few studies have been made on the dental conditions of such patients prior to surgery. The present study describes the most frequent prior oral diseases in this population group. A prospective, observational case-control study was designed involving 60 patients (30 with heart valve disease and 30 controls, with a mean age of 71 years in both groups). A dental exploration was carried out, with calculation of the DMFT (decayed, missing and filled teeth) index and recording of the periodontal parameters (plaque index, gingival bleeding index, periodontal pocket depth, and attachment loss). The oral mucosa was also examined, and panoramic X-rays were used to identify possible intrabony lesions. Significant differences in bacterial plaque index were observed between the two groups ( p <0.05), with higher scores in the patients with valve disease. Probing depth and the presence of moderate pockets were also greater in the patients with valve disease than among the controls ( p <0.01). Sixty percent of the patients with valve disease presented periodontitis. Patients scheduled for heart valve surgery should be examined for possible active periodontitis before the operation. Those individuals found to have periodontal disease should receive adequate periodontal treatment before heart surgery. Key words: Valve disease, aortic, mitral, heart surgery, periodontitis.

  8. 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].

  9. Anterior Urethral Valves

    Directory of Open Access Journals (Sweden)

    Vidyadhar P. Mali

    2006-07-01

    Full Text Available We studied the clinical presentation and management of four patients with anterior urethral valves; a rare cause of urethral obstruction in male children. One patient presented antenatally with oligohydramnios, bilateral hydronephrosis and bladder thickening suggestive of an infravesical obstruction. Two other patients presented postnatally at 1 and 2 years of age, respectively, with poor stream of urine since birth. The fourth patient presented at 9 years with frequency and dysuria. Diagnosis was established on either micturating cystourethrogram (MCU (in 2 or on cystoscopy (in 2. All patients had cystoscopic ablation of the valves. One patient developed a postablation stricture that was resected with an end-to-end urethroplasty. He had an associated bilateral vesicoureteric junction (VUJ obstruction for which a bilateral ureteric reimplantation was done at the same time. On long-term follow-up, all patients demonstrated a good stream of urine. The renal function is normal. Patients are continent and free of urinary infections. Anterior urethral valves are rare obstructive lesions in male children. The degree of obstruction is variable, and so they may present with mild micturition difficulty or severe obstruction with hydroureteronephrosis and renal impairment. Hence, it is important to evaluate the anterior urethra in any male child with suspected infravesical obstruction. The diagnosis is established by MCU or cystoscopy and the treatment is always surgical, either a transurethral ablation or an open resection. The long-term prognosis is good.

  10. MANAGEMENT OF FAILED MITRAL VALVE REPLACEMENT. THE DURBAN EXPERIENCE.

    Science.gov (United States)

    Kistan, D; Booysen, M; Alexander, G; Madiba, T E

    2017-06-01

    Mitral valve replacement is the procedure of choice in patients with severe mitral valve disease. However, these patients are surviving longer and are thus at an increased risk of prosthesis failure or valve-related complications. Study setting: Inkosi Albert Luthuli Central Hospital, a tertiary referral Hospital in Durban. Study population: All patients undergoing redo mechanical mitral valve replacement surgery between January 2005 and December 2014. Study design: Retrospective analysis of patients undergoing redo mitral valve replacement. Patients were identified from theatre record books, their files were electronically accessed and pertinent information extracted onto a data capture sheet. Information documented included demographics, duration to failure, INR, Albumin, HIV status, clinical findings and outcome. The data was stored on an Excel datasheet. Fifty-eight patients were documented (mean age 32 ± 15.81 years; M:F 1:3). Ten patients (17%) were HIV positive (median CD4 count 478). Mean duration between first surgery and redo was 8.8 years. Thirty-five patients (60%) had no co-morbidities. Presenting features at redo surgery were congestive cardiac failure (27), chest pain (11) and palpitations (17). Mean preoperative Ejection Fraction was 51.65 %. Twenty-nine patients (55%) had emergency redo surgery. Twenty-two patients (75%) had acute prosthetic valve thrombosis. Thirty-two patients had tricuspid regurgitation. Original pathology was documented in 23 patients (40%) as Rheumatic valve disease. Prosthetic valve thrombosis was documented in 31 patients (54%). The most commonly used valve was the On-X. Mean presenting INR was 1.96 + 1.2 and mean presenting serum albumin was 36.7 + 7.8 g/l. Forty-one patients (71%) were found to be compliant to Warfarin therapy prior to redo surgery. Mean ICU stay was 6 +9 days. Two patients died postoperatively. Mean followup was 32 + 26.6 months. Twelve patients (20.7%) developed postoperative complications. Patients

  11. Fracturing mechanics before valve-in-valve therapy of small aortic bioprosthetic heart valves.

    Science.gov (United States)

    Johansen, Peter; Engholt, Henrik; Tang, Mariann; Nybo, Rasmus F; Rasmussen, Per D; Nielsen-Kudsk, Jens Erik

    2017-10-13

    Patients with degraded bioprosthetic heart valves (BHV) who are not candidates for valve replacement may benefit from transcatheter valve-in-valve (VIV) therapy. However, in smaller-sized surgical BHV the resultant orifice may become too narrow. To overcome this, the valve frame can be fractured by a high-pressure balloon prior to VIV. However, knowledge on fracture pressures and mechanics are prerequisites. The aim of this study was to identify the fracture pressures needed in BHV, and to describe the fracture mechanics. Commonly used BHV of small sizes were mounted on a high-pressure balloon situated in a biplane fluoroscopic system with a high-speed camera. The instant of fracture was captured along with the balloon pressure. The valves were inspected for material protrusion and later dissected for fracture zone investigation and description. The valves with a polymer frame fractured at a lower pressure (8-10 atm) than those with a metal stent (19-26 atm). None of the fractured valves had elements protruding. VIV procedures in small-sized BHV may be performed after prior fracture of the valve frame by high-pressure balloon dilatation. This study provides tentative guidelines for expected balloon sizes and pressures for valve fracturing.

  12. Practical use of valve seating machine with remote control system for main steam isolation valve at N.P.S

    International Nuclear Information System (INIS)

    Ito, Sadao; Noda, Hiroshi; Sadamura, Morito; Utsunomiya, Yasushi.

    1975-01-01

    The main steam isolation valves in BWR power stations are installed at the boundary of reactor containment vessels, and 2 valves in each main steam system total 8 valves in a plant. They are pneumatically operated Y type globe valves for preventing the release of radioactive substances in the atmosphere in case of the breaking of main steam pipes and also preventing the loss of coolant in case of the breaking of recirculating equipments. Therefore careful leak test, inspection, and seat-fitting are carried out to the valves at each regular maintenance. The manual maintenance work is difficult because of narrow space and the reduction of exposure, and the seat-fitting work requires the skill of high degree, therefore Okano Valve Manufacturing Co. and Tokyo Electric Power Co. jointly started the research and development of an automatic valve seating machine, and successfully put it to practical use in Fukushima No.1 Nuclear Power Station in Nov. 1974. First, the problems in the manual seat-fitting work were investigated, and the means to mechanically solve them were materialized with a prototype machine. After its mock-up test, an actual machine was designed and manufactured. The test result showed remarkable reduction of exposure and labor-saving, and the leak evaluation was sufficiently below the allowable value. (Kako, I.)

  13. Automatic fire hydrant valve development

    International Nuclear Information System (INIS)

    Drumheller, K.

    1976-01-01

    The development of a remotely-controlled valve to operate a fire hydrant is described. Assembled from off-the-shelf components, the prototype illustrates that a valve light enough to be handled by one man is possible. However, it does not have the ruggedness or reliability needed for actual fire-fighting operations. Preliminary testing by City of Tacoma fire department personnel indicates that the valve may indeed contribute significantly to fire-fighting efficiency

  14. [Ahmed valve in glaucoma surgery].

    Science.gov (United States)

    Bikbov, M M; Khusnitdinov, I I

    This is a review on Ahmed valve application in glaucoma surgery. It contains, in particular, data on the Ahmed valve efficiency, results of experimental and histological studies of filtering bleb encapsulation, examines the use of antimetabolites and anti-VEGF agents, and discusses implantation techniques. The current appraisal of antimetabolites delivery systems integrated into the Ahmed valve is presented. Various complications encountered in practice and preventive measures are also covered.

  15. A comparison of conventional surgery, transcatheter aortic valve replacement, and sutureless valves in "real-world" patients with aortic stenosis and intermediate- to high-risk profile.

    Science.gov (United States)

    Muneretto, Claudio; Alfieri, Ottavio; Cesana, Bruno Mario; Bisleri, Gianluigi; De Bonis, Michele; Di Bartolomeo, Roberto; Savini, Carlo; Folesani, Gianluca; Di Bacco, Lorenzo; Rambaldini, Manfredo; Maureira, Juan Pablo; Laborde, Francois; Tespili, Maurizio; Repossini, Alberto; Folliguet, Thierry

    2015-12-01

    We sought to investigate the clinical outcomes of patients with isolated severe aortic stenosis and an intermediate- to high-risk profile treated by means of conventional surgery (surgical aortic valve replacement), sutureless valve implantation, or transcatheter aortic valve replacement in a multicenter evaluation. Among 991 consecutive patients with isolated severe aortic stenosis and an intermediate- to high-risk profile (Society of Thoracic Surgeons score >4 and logistic European System for Cardiac Operative Risk Evaluation I >10), a propensity score analysis was performed on the basis of the therapeutic strategy: surgical aortic valve replacement (n = 204), sutureless valve implantation (n = 204), and transcatheter aortic valve replacement (n = 204). Primary end points were 30-day mortality and overall survival at 24-month follow-up; the secondary end point was survival free from a composite end point of major adverse cardiac events (defined as cardiac-related mortality, myocardial infarction, cerebrovascular accidents, and major hemorrhagic events) and periprosthetic regurgitation greater than 2. Thirty-day mortality was significantly higher in the transcatheter aortic valve replacement group (surgical aortic valve replacement = 3.4% vs sutureless = 5.8% vs transcatheter aortic valve replacement = 9.8%; P = .005). The incidence of postprocedural was 3.9% in asurgical aortic valve replacement vs 9.8% in sutureless vs 14.7% in transcatheter aortic valve replacement (Prisk factor for overall mortality hazard ratio (hazard ratio, 2.5; confidence interval, 1.1-4.2; P = .018). The use of transcatheter aortic valve replacement in patients with an intermediate- to high-risk profile was associated with a significantly higher incidence of perioperative complications and decreased survival at short- and mid-term when compared with conventional surgery and sutureless valve implantation. Copyright © 2015 The American Association for Thoracic Surgery. Published by

  16. Early Outcomes of Sutureless Aortic Valves

    Directory of Open Access Journals (Sweden)

    Muhammet Onur Hanedan

    2016-06-01

    Full Text Available Background: In elderly high-risk surgical patients, sutureless aortic valve replacement (AVR should be an alternative to standard AVR. The potential advantages of sutureless aortic prostheses include reducing cross-clamping and cardiopulmonary bypass (CPB time and facilitating minimally invasive surgery and complex cardiac interventions, while maintaining satisfactory hemodynamic outcomes and low rates of paravalvular leakage. The current study reports our single-center experience regarding the early outcomes of sutureless aortic valve implantation. Methods: Between October 2012 and June 2015, 65 patients scheduled for surgical valve replacement with symptomatic aortic valve disease and New York Heart Association function of class II or higher were included to this study. Perceval S (Sorin Biomedica Cardio Srl, Sallugia, Italy and Edwards Intuity (Edwards Lifesciences, Irvine, CA, USA valves were used. Results: The mean age of the patients was 71.15±8.60 years. Forty-four patients (67.7% were female. The average preoperative left ventricular ejection fraction was 56.9±9.93. The CPB time was 96.51±41.27 minutes and the cross-clamping time was 60.85±27.08 minutes. The intubation time was 8.95±4.19 hours, and the intensive care unit and hospital stays were 2.89±1.42 days and 7.86±1.42 days, respectively. The mean quantity of drainage from chest tubes was 407.69±149.28 mL. The hospital mortality rate was 3.1%. A total of five patients (7.69% died during follow-up. The mean follow-up time was 687.24±24.76 days. The one-year survival rate was over 90%. Conclusion: In the last few years, several models of valvular sutureless bioprostheses have been developed. The present study evaluating the single-center early outcomes of sutureless aortic valve implantation presents the results of an innovative surgical technique, finding that it resulted in appropriate hemodynamic conditions with acceptable ischemic time.

  17. Early Outcomes of Sutureless Aortic Valves.

    Science.gov (United States)

    Hanedan, Muhammet Onur; Mataracı, İlker; Yürük, Mehmet Ali; Özer, Tanıl; Sayar, Ufuk; Arslan, Ali Kemal; Ziyrek, Uğur; Yücel, Murat

    2016-06-01

    In elderly high-risk surgical patients, sutureless aortic valve replacement (AVR) should be an alternative to standard AVR. The potential advantages of sutureless aortic prostheses include reducing cross-clamping and cardiopulmonary bypass (CPB) time and facilitating minimally invasive surgery and complex cardiac interventions, while maintaining satisfactory hemodynamic outcomes and low rates of paravalvular leakage. The current study reports our single-center experience regarding the early outcomes of sutureless aortic valve implantation. Between October 2012 and June 2015, 65 patients scheduled for surgical valve replacement with symptomatic aortic valve disease and New York Heart Association function of class II or higher were included to this study. Perceval S (Sorin Biomedica Cardio Srl, Sallugia, Italy) and Edwards Intuity (Edwards Lifesciences, Irvine, CA, USA) valves were used. The mean age of the patients was 71.15±8.60 years. Forty-four patients (67.7%) were female. The average preoperative left ventricular ejection fraction was 56.9±9.93. The CPB time was 96.51±41.27 minutes and the cross-clamping time was 60.85±27.08 minutes. The intubation time was 8.95±4.19 hours, and the intensive care unit and hospital stays were 2.89±1.42 days and 7.86±1.42 days, respectively. The mean quantity of drainage from chest tubes was 407.69±149.28 mL. The hospital mortality rate was 3.1%. A total of five patients (7.69%) died during follow-up. The mean follow-up time was 687.24±24.76 days. The one-year survival rate was over 90%. In the last few years, several models of valvular sutureless bioprostheses have been developed. The present study evaluating the single-center early outcomes of sutureless aortic valve implantation presents the results of an innovative surgical technique, finding that it resulted in appropriate hemodynamic conditions with acceptable ischemic time.

  18. Thermal fatigue behavior of valves

    International Nuclear Information System (INIS)

    Moinereau, D.; Scliffet, L.; Capion, J.C.; Genette, P.

    1991-01-01

    This paper reports that valves of pressurized water reactors are exposed to thermal shocks during transient operations. The numerous thermal shock tests performed on valves on the EDF test facilities have shown the sensibility of fillets and geometrical discontinuities to thermal fatigue: cracks can appear in those areas and grow through the valve body. Valves systems designated as level 1 must be designed to withstand fatigue up to the second isolation valve: the relevant rule is specified in the paragraph B 3500 of the French RCCM code. It is a simplified method which doesn't require finite element calculations. Many valve systems have been designed according to this rule and have been operated without accident. However, in one case, important cracks were found in the fillet of a check-valve after numerous thermal shocks. Calculation of the valve's behavior according to the RCCM code to estimate the fatigue damage resulting from thermal shocks led to a low damage factor, which doesn't agree with the experimental results. This was confirmed by new testings and showed the inadequacy of B 3500 rule for thermal transients. On this base a new rule is proposed to estimate fatigue damage resulting from thermal shocks. An experimental program has been realized to validate this rule. Axisymetrical analytical mock-ups with different geometries and one check-valve in austenitic stainless steel 316 L have been submitted to hot thermal shocks of 210 degrees C magnitude

  19. 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.

  20. Fluid mechanics of heart valves.

    Science.gov (United States)

    Yoganathan, Ajit P; He, Zhaoming; Casey Jones, S

    2004-01-01

    Valvular heart disease is a life-threatening disease that afflicts millions of people worldwide and leads to approximately 250,000 valve repairs and/or replacements each year. Malfunction of a native valve impairs its efficient fluid mechanic/hemodynamic performance. Artificial heart valves have been used since 1960 to replace diseased native valves and have saved millions of lives. Unfortunately, despite four decades of use, these devices are less than ideal and lead to many complications. Many of these complications/problems are directly related to the fluid mechanics associated with the various mechanical and bioprosthetic valve designs. This review focuses on the state-of-the-art experimental and computational fluid mechanics of native and prosthetic heart valves in current clinical use. The fluid dynamic performance characteristics of caged-ball, tilting-disc, bileaflet mechanical valves and porcine and pericardial stented and nonstented bioprostheic valves are reviewed. Other issues related to heart valve performance, such as biomaterials, solid mechanics, tissue mechanics, and durability, are not addressed in this review.

  1. Surge-damping vacuum valve

    International Nuclear Information System (INIS)

    Bullock, J.C.; Kelley, B.E.

    1977-01-01

    A valve for damping out flow surges in a vacuum system is described. The surge-damping mechanism consists of a slotted, spring-loaded disk adjacent to the valve's vacuum port (the flow passage to the vacuum roughing pump). Under flow surge conditions, the differential pressure forces the disk into a sealing engagement with the vacuum port, thereby restricting the gas flow path to narrow slots in the disk's periphery. The increased flow damps out the flow surge. When pressure is equalized on both sides of the valve, the spring load moves the disk away from the port to restore full flow conductance through the valve

  2. ADAM®/SIPLUG®: An innovative valve monitoring system

    International Nuclear Information System (INIS)

    Muñoz, L.; Krell, M.

    2012-01-01

    Optimized maintenance strategies are a key aspect for safe and undisturbed plant operation. Innovative valve service solutions, e.g. valve diagnostics can support this in an efficient way. The ADAM®/SIPLUG® valve monitoring system allows full online monitoring of valves and actuators with automatic evaluation and assessment. Especially for safety-related and operation-related valves this provides valuable information on components condition to ensure proper function and contribute to optimization of maintenance strategies as well as effective maintenance performance. The new SIPLUG®-4 modules are the evolutionary solution for valve diagnosis at the Motor Control Center (MCC). As the SIPLUG®-4 can be installed directly in the MCC outgoing actuator power cable it allows an easy installation in existing switchgear cabinets. Measurement at MCC means also zero effort for performance of diagnostics reducing the number of on-site activities. This results in decrease of maintenance costs and dose rates for deployed personnel. The ADAM® evaluation software and database was developed in parallel with the hardware. It provides automatic analysis of the monitoring results using the limit values specified for the valves. The measured data can be transmitted via the power plant’s local area network to the ADAM® data server, if the SIPLUG® online hardware is installed. With the mobile solution, the data can be transmitted via serial or USB interface to a PC or notebook. With this solution all measurement information will be available immediately in the offices of plant engineers. Also, with SIPLUG® online all operations of valves can be automatically recorded. More than 25 years of experience in various plants worldwide show that the application of ADAM®/SIPLUG® valve diagnostics solution leads to increased plant safety and availability. Some of the references for ADAM®/SIPLUG® are Germany, Switzerland, Brazil, Spain and Eastern Europe. (author)

  3. Operating Temperatures of a Sodium-Cooled Exhaust Valve as Measured by a Thermocouple

    Science.gov (United States)

    Sanders, J. C.; Wilsted, H. D.; Mulcahy, B. A.

    1943-01-01

    A thermocouple was installed in the crown of a sodium-cooled exhaust valve. The valve was then tested in an air-cooled engine cylinder and valve temperatures under various engine operating conditions were determined. A temperature of 1337 F was observed at a fuel-air ratio of 0.064, a brake mean effective pressure of 179 pounds per square inch, and an engine speed of 2000 rpm. Fuel-air ratio was found to have a large influence on valve temperature, but cooling-air pressure and variation in spark advance had little effect. An increase in engine power by change of speed or mean effective pressure increased the valve temperature. It was found that the temperature of the rear spark-plug bushing was not a satisfactory indication of the temperature of the exhaust valve.

  4. Transfemoral Aortic Valve Implantation with the New Edwards Sapien 3 Valve for Treatment of Severe Aortic Stenosis-Impact of Valve Size in a Single Center Experience.

    Directory of Open Access Journals (Sweden)

    Jochen Wöhrle

    Full Text Available The third generation Edwards Sapien 3 (Edwards Lifesciences Inc., Irvine, California system was optimized to reduce residual aortic regurgitation and vascular complications.235 patients with severe symptomatic aortic stenosis were prospectively enrolled. Transcatheter aortic valve implantations (TAVI were performed without general anesthesia by transfemoral approach. Patients were followed for 30 days. Patients received 23mm (N = 77, 26mm (N = 91 or 29mm (N = 67 valve based on pre-procedural 256 multislice computer tomography. Mean oversizing did not differ between the 3 valves. There was no residual moderate or severe aortic regurgitation. Rate of mild aortic regurgitation and regurgitation index did not differ between groups. There was no switch to general anesthesia or conversion to surgery. Rate of major vascular complication was 3.0% with no difference between valve and delivery sheath sizes. Within 30 days rates of all cause mortality (2.6% and stroke (2.1% were low.In patients with severe aortic stenosis transfemoral TAVI with the Edwards Sapien 3 valve without general anesthesia was associated with a high rate of device success, no moderate or severe residual aortic regurgitation, low rates of major vascular complication, mortality and stroke within 30 days with no difference between the 3 valve sizes.ClinicalTrials.gov NCT02162069.

  5. Heart Valve Surgery Recovery and Follow Up

    Science.gov (United States)

    ... Guide: Understanding Your Heart Valve Problem | Spanish Symptom Tracker | Spanish Pre-surgery Checklist | Spanish What Is Heart ... Heart Valves • Heart Valve Problems and Causes • Risks, Signs and Symptoms • Accurate Diagnosis • Treatment Options • Recovery and ...

  6. Aortic Regurgitation in Patients Undergoing Transcatheter Aortic Valve Replacement With the Self-Expanding CoreValve Versus the Balloon-Expandable SAPIEN XT Valve.

    Science.gov (United States)

    Kiramijyan, Sarkis; Magalhaes, Marco A; Koifman, Edward; Didier, Romain; Escarcega, Ricardo O; Baker, Nevin C; Negi, Smita I; Minha, Sa'ar; Torguson, Rebecca; Jiaxiang, Gai; Asch, Federico M; Wang, Zuyue; Okubagzi, Petros; Gaglia, Michael A; Ben-Dor, Itsik; Satler, Lowell F; Pichard, Augusto D; Waksman, Ron

    2016-05-01

    The incidence of aortic regurgitation (AR) after transcatheter aortic valve replacement (TAVR) in a self-expanding and a balloon-expandable system is controversial. This study aimed to examine the incidence and severity of post-TAVR AR with the CoreValve (CV) versus the Edwards XT Valve (XT). Baseline, procedural, and postprocedural inhospital outcomes were compared. The primary end point was the incidence of post-TAVR AR of any severity, assessed with a transthoracic echocardiogram, in the CV versus XT groups. A multivariate logistic regression analysis was completed to evaluate for correlates of the primary end point. The secondary end points included the change in severity of AR at 30-day and 1-year follow-up. A total of 223 consecutive patients (53% men, mean age 82 years) who had transfemoral TAVR with either a CV (n = 119) or XT (n = 104) were evaluated. The rates of post-TAVR AR in the groups were similar, and there was no evidence of more-than-moderate AR in either group. There were significant differences in the rates of intraprocedural balloon postdilation with the CV (17.1%) versus XT valve (5.8%; p = 0.009) and in the rates of intraprocedural implantation of a second valve-in-valve prosthesis with the CV (9.9%) versus XT valve (2.2%; p = 0.036). There were no significant differences in inhospital safety outcomes between the 2 groups. In conclusion, the incidence of post-TAVR AR is similar between the CV and the XT valve when performed by experienced operators using optimal intraprocedural strategies, as deemed appropriate, to mitigate the severity of AR. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Cobalt reduction of NSSS valve hardfacings for ALARA

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Joo Hak; Lee, Sang Sub [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1994-07-01

    This report informs NSSS designer that replacement of materials is one of the major means of ALARA implementation, and describes that NSSS valves with high-cobalt hardfacing are significant contributors to post-shutdown radiation fields caused by activation of cobalt-59 to cobalt-60. Generic procedures for implementing cobalt reduction programs for valves are presented. Discussions are presented of the general and specific design requirements for valve hardfacing in nuclear service. The nuclear safety issues involved with changing valve hardfacing materials are discussed. The common methods used to deposit hardfacing materials are described together with an explanation of the wear measurements. Wear resistance, corrosion resistance, friction coefficient, and mechanical properties of candidate hardfacing alloys are given. World-wide nuclear utility experience with cobalt-free hardfacing alloys is described. The use of low-cobalt or cobalt-free alloys in other nuclear plant components is described. 17 figs., 38 tabs., 18 refs. (Author).

  8. [Valve-sparing Replacement in Patients with Aortic Root Dilatation].

    Science.gov (United States)

    Yamazaki, Kazuhiro; Minatoya, Kenji; Ueda, Ryoma; Takehara, Masato; Sakamoto, Kazuhisa; Ide, Yujiro; Kanemitsu, Hideo; Ueyama, Koji; Ikeda, Tadashi

    2018-01-01

    Valve-sparing root replacement is increasingly used to overcome drawbacks associated with valvular prostheses. In our institution, 7 patients underwent valve-sparing root replacement from August 2016 to July 2017. The mean age was 45 years (range, 14~69 years). Three patients had Marfan syndrome and 1 had Loeys-Dietz syndrome with acute aortic dissection. All patients underwent surgery with reimplantation technique using a Valsalva graft. Two patients required repair of aortic valve leaflet prolapse. All patients had an excellent clinical course, with mild or no aortic regurgitation and a decrease in end-diastolic volume on echocardiography. These results support the continued use of valve-sparing root replacement in selected patients.

  9. Modal-Based Design Improvement of a Butterfly Valve Disc

    Directory of Open Access Journals (Sweden)

    Marius Draghiciu

    2017-11-01

    Full Text Available The dynamic behaviour control of a butterfly valve is important because, when one of the valve disc natural frequency is close to the frequency of vortex shedding, which appears when the valve is fully open or partially closed, resonance may appear and vibration with significant amplitudes is generated. This paper presents an example by how the design of a butterfly valve disc can be improved by using a modal analysis performed by means of the finite element method. For this purpose, the research reveals the way in which the natural frequencies of the disc can be modified by applying stiffening ribs or changing the dimensions, respective the position of these ribs.

  10. Cobalt reduction of NSSS valve hardfacings for ALARA

    International Nuclear Information System (INIS)

    Kim, Joo Hak; Lee, Sang Sub

    1994-07-01

    This report informs NSSS designer that replacement of materials is one of the major means of ALARA implementation, and describes that NSSS valves with high-cobalt hardfacing are significant contributors to post-shutdown radiation fields caused by activation of cobalt-59 to cobalt-60. Generic procedures for implementing cobalt reduction programs for valves are presented. Discussions are presented of the general and specific design requirements for valve hardfacing in nuclear service. The nuclear safety issues involved with changing valve hardfacing materials are discussed. The common methods used to deposit hardfacing materials are described together with an explanation of the wear measurements. Wear resistance, corrosion resistance, friction coefficient, and mechanical properties of candidate hardfacing alloys are given. World-wide nuclear utility experience with cobalt-free hardfacing alloys is described. The use of low-cobalt or cobalt-free alloys in other nuclear plant components is described. 17 figs., 38 tabs., 18 refs. (Author)

  11. Magnetostatic Analysis of a Pinch Mode Magnetorheological Valve

    Directory of Open Access Journals (Sweden)

    Gołdasz Janusz

    2017-09-01

    Full Text Available The study deals with the pinch mode of magnetorheological (MR fluids’ operation and its application in MR valves. By applying the principle in MR valves a highly non-uniform magnetic field can be generated in flow channels in such a way to solidify the portion of the material that is the nearest to the flow channel’s walls. This is in contrary to well-known MR flow mode valves. The authors investigate a basic pinch mode valve in several fundamental configurations, and then examine their magnetic circuits through magnetostatic finite-element (FE analysis. Flux density contour maps are revealed and basic performance figures calculated and analysed. The FE analysis results yield confidence in that the performance of MR pinch mode devices can be effectively controlled through electromagnetic means.

  12. Preoperative computer tomography evaluation in transcatheter aortic valve replacement (TAVI)

    International Nuclear Information System (INIS)

    Groudeva, V.; Stoynova, V.; Trendafilova, D.; Dzhorgova, Y.; Nachev, G.

    2014-01-01

    Transcatheter aortic valve replacement is rapidly emerging technique alternative to surgery in high risk patients. Imaging and especially computer tomography is important in preoperative assessment of the aortic ring and the prosthetic valve choice. The aim of this study is to share authors initial experience in CT assessment of the aortic ring prior to Transcatheter aortic valve replacement. 49 patients (mean age 76,55) underwent 320 rows MDCT (Acquilon One) prior TAVI. Protocol involved scanning from thoracic inlet to common femoral arteries. Aortic root size, aortic diameter at the level of coronary sinuses and the sinotubular junction and distance to coronary ostia were evaluated on a Vitrea work station. MDCT established maximal aortic ring diameter from 18 to 31 mm mean 25,04 mm while the lesser rate was from 16 to 21 mm. Accordingly positioned prostheses were in 34,75% No. 23, in 49% - No. 26 and in16,3% - No. 29. MDCT is crucial in aortic valve assessment prior to TAVI in experienced hands and multidisciplinary team. (authors) Key words: TRANSCATHETER AORTIC VALVE REPLACEMENT (TAVI). MDCT AORTIC VALVE ASSESSMENT

  13. Outcomes of Reoperative Valve Replacement in Patients with Prosthetic Valve Endocarditis: A 20-Year Experience

    Directory of Open Access Journals (Sweden)

    Young Woong Kim

    2018-02-01

    Full Text Available Background: Prosthetic valve endocarditis (PVE is a serious complication of cardiac valve replacement, and many p atients with P VE r equire r eoperation. The aim of t his study was to r eview our institutional 2 0 -year experience of surgical reoperative valve replacement in patients with PVE. Methods: A retrospective study was performed on 84 patients (mean age, 54.8±12.7 years; 51 males who were diagnosed with PVE and underwent reoperative valve replacement from January 1995 to December 2016. Results: PVE was found in 1 valve in 61 cases (72.6%, and in 2 or more valves in 23 cases (27.4%. The median follow-up duration was 47.3 months (range, 0 to 250 months. Postoperative complications occurred in 39 patients (46.4%. Reinfection occurred in 6 cases, all within 1 year. The freedom from reinfection rate at 5 years was 91.0%±3.5%. The overall survival rates at 5 and 10 years were 64.4%±5.8% and 54.3%±7.3%, respectively. In stepwise multivariable Cox proportional hazard models, older age (hazard ratio [HR], 1.48; 95% confidence interval [CI], 1.05 to 2.10; p=0.027 and cardiopulmonary bypass (CPB time (HR, 1.03; 95% CI, 1.00 to 1.0 1; p =0 . 0 33 e merged a s independent risk f actors f or d eath. Conclusion: Older age and a longer CPB time were associated with an increased risk of overall mortality in PVE patients.

  14. Survival and freedom from aortic valve-related reoperation after valve-sparing aortic root replacement in 1015 patients.

    Science.gov (United States)

    Kari, Fabian A; Doll, Kai-Nicolas; Hemmer, Wolfgang; Liebrich, Markus; Sievers, Hans-Hinrich; Richardt, Doreen; Reichenspurner, Hermann; Detter, Christian; Siepe, Matthias; Czerny, Martin; Beyersdorf, Friedhelm

    2016-04-01

    The aim of this study was to characterize mortality and aortic valve replacement after valve-sparing aortic root replacement (V-SARR) in a multicentre cohort. Between 1994 and 2014, 1015 patients had V-SARR with (n = 288, 28%) or without cusp/commissure repair (n = 727, 72%) at the centres of Lübeck (n = 343, 34%), Stuttgart (n = 346, 34%), Hamburg (n = 109, 11%) and Freiburg (n = 217, 21%), Germany. Comparative survival of an age- and gender-matched general population was calculated. Log-rank tests and multiple logistic regression were used to identify risk factors. The mean follow-up was 5.2 ± 3.9 years. Cumulative follow-up comprised 2933 patient-years. Early survival was 98%. NYHA status and aneurysm size were predictive of death during mid-term follow-up (P = 0.025). Freedom from aortic valve replacement was 90% at 8 years, with the type of V-SARR (root remodelling, David II) being a risk factor (P = 0.015). Bicuspid aortic valve (P = 0.26) and initial valve function (P = 0.4) did not impact reoperation. The need of additional valve repair (cusps/commissures) was not linked to reoperation: freedom from aortic valve replacement at 8 years was 84% if cusp repair was performed versus 90% if V-SARR alone was performed (P = 0.218). Marfan syndrome had no impact on survival or on aortic valve replacement. Mid-term survival of patients after V-SARR is comparable with that of a matched general population. The regurgitant bicuspid aortic valve is a favourable substrate for V-SARR. Prophylactic surgery should be performed before symptoms or large aneurysms are present to achieve optimal mid-term outcomes. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  15. Low radiation dose non-contrast cardiac CT: is it of value in the evaluation of mechanical aortic valve

    International Nuclear Information System (INIS)

    Bazeed, Mohamed Fayez; Moselhy, Mohamed Saleh; Rezk, Ahmad Ibrahim; Al-Murayeh, Mushabab Ayedh

    2012-01-01

    Background: Prosthetic bileaflet mechanical valve function has been traditionally evaluated using echocardiography and fluoroscopy. Multidetector computed tomography (MDCT) is a novel technique for cardiac evaluation. Purpose: To evaluate bileaflet mechanical aortic valves using a low-milliampere (mA), non-contrast MDCT protocol with a limited scan range. Material and Methods: Forty patients with a bileaflet mechanical aortic valve were evaluated using a non-contrast, low-mA, ECG-gated 64 MDCT protocol with a limited scan range. MDCT findings of opening and closing valve angles were correlated to fluoroscopy and echocardiography. Also, the valve visibility was evaluated on MDCT and fluoroscopy according to a 3-point grading scale. Results: The visualization score with the MDCT was significantly superior to the fluoroscopy (3 vs. 2.7). A strong correlation was noted between the opening (r = 0.82) and closing (r = 0.96) valve angles with MDCT and fluoroscopy without a statistically significant difference (P = 0.31 and 0.16, respectively). The mean effective radiation dose of the suggested protocol was 4 ± 0.5 mSv. Five valves were evaluated using transesophageal echocardiography because the valves were difficult to evaluate with transthoracic echocardiography, and all of these valves were evaluated optimally with MDCT. A high-pressure gradient was noted in nine valves, and the MDCT showed that seven of these valves inadequately opened, and two valves opened well, which resulted in patient valve mismatch. Incomplete valve closure was noted in five valves, and the echocardiography showed significant transvalvular regurgitation in all five valves. Conclusion: MDCT can provide a precise measurement of valve function and can potentially evaluate high-pressure gradients and transvalvular regurgitation

  16. Low radiation dose non-contrast cardiac CT: is it of value in the evaluation of mechanical aortic valve

    Energy Technology Data Exchange (ETDEWEB)

    Bazeed, Mohamed Fayez (Dept. of Diagnostic Radiology, Faculty of Medicine, Mansoura Univ. (Egypt)), email: m_bazeed@yahoo.com; Moselhy, Mohamed Saleh (Cardiology Dept. Faculty of Medicine, Suez Canal Univ. (Egypt)); Rezk, Ahmad Ibrahim (Dept. of Cardiac Surgery, Faculty of Medicine, Aim Shams Univ. (Egypt)); Al-Murayeh, Mushabab Ayedh (Dept. of Cardiac Services, Armed Forces Hospitals Southern Region (Saudi Arabia))

    2012-05-15

    Background: Prosthetic bileaflet mechanical valve function has been traditionally evaluated using echocardiography and fluoroscopy. Multidetector computed tomography (MDCT) is a novel technique for cardiac evaluation. Purpose: To evaluate bileaflet mechanical aortic valves using a low-milliampere (mA), non-contrast MDCT protocol with a limited scan range. Material and Methods: Forty patients with a bileaflet mechanical aortic valve were evaluated using a non-contrast, low-mA, ECG-gated 64 MDCT protocol with a limited scan range. MDCT findings of opening and closing valve angles were correlated to fluoroscopy and echocardiography. Also, the valve visibility was evaluated on MDCT and fluoroscopy according to a 3-point grading scale. Results: The visualization score with the MDCT was significantly superior to the fluoroscopy (3 vs. 2.7). A strong correlation was noted between the opening (r = 0.82) and closing (r = 0.96) valve angles with MDCT and fluoroscopy without a statistically significant difference (P = 0.31 and 0.16, respectively). The mean effective radiation dose of the suggested protocol was 4 +- 0.5 mSv. Five valves were evaluated using transesophageal echocardiography because the valves were difficult to evaluate with transthoracic echocardiography, and all of these valves were evaluated optimally with MDCT. A high-pressure gradient was noted in nine valves, and the MDCT showed that seven of these valves inadequately opened, and two valves opened well, which resulted in patient valve mismatch. Incomplete valve closure was noted in five valves, and the echocardiography showed significant transvalvular regurgitation in all five valves. Conclusion: MDCT can provide a precise measurement of valve function and can potentially evaluate high-pressure gradients and transvalvular regurgitation

  17. 241-AN-A valve pit manifold valves and position indication acceptance test procedure

    Energy Technology Data Exchange (ETDEWEB)

    VANDYKE, D.W.

    1999-08-25

    This document describes the method used to test design criteria for gear actuated ball valves installed in 241-AN-A Valve Pit located at 200E Tank Farms. The purpose of this procedure is to demonstrate the following: Equipment is properly installed, labeled, and documented on As-Built drawings; New Manifold Valves in the 241-AN-A Valve Pit are fully operable using the handwheel of the valve operators; New valve position indicators on the valve operators will show correct valve positions; New valve position switches will function properly; and New valve locking devices function properly.

  18. The Double-Orifice Valve Technique to Treat Tricuspid Valve Incompetence.

    Science.gov (United States)

    Hetzer, Roland; Javier, Mariano; Delmo Walter, Eva Maria

    2016-01-01

    A straightforward tricuspid valve (TV) repair technique was used to treat either moderate or severe functional (normal valve with dilated annulus) or for primary/organic (Ebstein's anomaly, leaflet retraction/tethering and chordal malposition/tethering, with annular dilatation) TV incompetence, and its long-term outcome assessed. A double-orifice valve technique was employed in 91 patients (mean age 52.6 ± 23.2 years; median age 56 years; range: 0.6-82 years) with severe tricuspid regurgitation. Among the patients, three had post-transplant iatrogenic chordal rupture, five had infective endocarditis, 11 had mitral valve insufficiency, 23 had Ebstein's anomaly, and 47 had isolated severe TV incompetence. The basic principle was to reduce the distance between the coapting leaflets, wherein the most mobile leaflet could coapt to the opposite leaflet, by creating two orifices, ensuring valve competence. The TV repair was performed through a median sternotomy or right anterior thoracotomy in the fifth intercostal space under cardiopulmonary bypass. The degree and extent of creating a double-valve orifice was determined by considering the minimal body surface area (BSA)-related acceptable TV diameter. Repair was accomplished by passing pledgeted mattress sutures from the middle of the true anterior annulus to a spot on the opposite septal annulus, located approximately two-thirds of the length of the septal annulus to avoid injury to the bundle of His. The annular apposition divides the TV into a larger anterior and a smaller posterior orifices, enabling valve closure, on both sides. In adults, the diameter of the anterior valve orifice should be 23-25 mm, and the posterior orifice 15-18 mm; thus, the total valve orifice area is 5-6 cm2. In children, the total valve orifice should be a standard deviation of 1.7 mm for a BSA of 1.0m2. During a mean follow up of 8.7 ± 1.34 years (median 10 years; range: 1.5-25.9 years) there have been no reoperations for TV insufficiency

  19. Aortic valve replacement

    DEFF Research Database (Denmark)

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

    2008-01-01

    mortality were collected. Group analysis by patient geographic distribution and by annular diameter of the prosthesis utilized was conducted. Patients with a manufacturer's labeled prosthesis size > or = 21 mm were assigned to the 'large' aortic size subset, while those with a prosthesis size ... differences in the distribution of either gender or BSA. In the multivariable model, south European patients were seven times more likely to receive a smaller-sized aortic valve (OR = 6.5, 95% CI = 4.82-8.83, p

  20. Bireactor Electronuclear Systems with Liquid Cadmium Valve

    CERN Document Server

    Bznuni, S A; Zhamkochyan, V M; ASosnin, A N; Polanski, A; Khudaverdyan, A H

    2002-01-01

    Three main types of bireactor electronuclear systems are discussed. From the point of view of assuring high level of functional characteristics and safety bireactor electronuclear systems with booster using enriched uranium (20 %) and with a liquid cadmium valve appears to be the most effective. It is shown by means of Monte-Carlo modeling that such operation conditions can be achieved which lead to the destruction of the intermediate cadmium layer making the systems supercritical (k_{eff}>1). One can avoid the problem by using a special design of the liquid cadmium valve. In comparison with other nuclear systems (critical reactors, one-reactor electronuclear systems) cascade electronuclear systems have essential advantages allowing the decrease of the proton beam current by one order of magnitude and providing at same time the necessary level of power generation and neutron flux. Availability of both the thermal and fast cones allows one to transmute not only transuranics but also the fission products - cesi...

  1. Curved butterfly bileaflet prosthetic cardiac valve

    Science.gov (United States)

    McQueen, David M.; Peskin, Charles S.

    1991-06-25

    An annular valve body having a central passageway for the flow of blood therethrough with two curved leaflets each of which is pivotally supported on an accentric positioned axis in the central passageway for moving between a closed position and an open position. The leaflets are curved in a plane normal to the eccentric axis and positioned with the convex side of the leaflets facing each other when the leaflets are in the open position. Various parameters such as the curvature of the leaflets, the location of the eccentric axis, and the maximum opening angle of the leaflets are optimized according to the following performance criteria: maximize the minimum peak velocity through the valve, maximize the net stroke volume, and minimize the mean forward pressure difference, thereby reducing thrombosis and improving the hemodynamic performance.

  2. Defense High Level Waste Disposal Container System Description Document

    International Nuclear Information System (INIS)

    Pettit, N. E.

    2001-01-01

    The Defense High Level Waste Disposal Container System supports the confinement and isolation of waste within the Engineered Barrier System of the Monitored Geologic Repository (MGR). Disposal containers are loaded and sealed in the surface waste handling facilities, transferred to the underground through the accesses using a rail mounted transporter, and emplaced in emplacement drifts. The defense high level waste (HLW) disposal container provides long-term confinement of the commercial HLW and defense HLW (including immobilized plutonium waste forms [IPWF]) placed within disposable canisters, and withstands the loading, transfer, emplacement, and retrieval loads and environments. US Department of Energy (DOE)-owned spent nuclear fuel (SNF) in disposable canisters may also be placed in a defense HLW disposal container along with commercial HLW waste forms, which is known as co-disposal. The Defense High Level Waste Disposal Container System provides containment of waste for a designated period of time, and limits radionuclide release. The disposal container/waste package maintains the waste in a designated configuration, withstands maximum handling and rockfall loads, limits the individual canister temperatures after emplacement, resists corrosion in the expected handling and repository environments, and provides containment of waste in the event of an accident. Defense HLW disposal containers for HLW disposal will hold up to five HLW canisters. Defense HLW disposal containers for co-disposal will hold up to five HLW canisters arranged in a ring and one DOE SNF canister inserted in the center and/or one or more DOE SNF canisters displacing a HLW canister in the ring. Defense HLW disposal containers also will hold two Multi-Canister Overpacks (MCOs) and two HLW canisters in one disposal container. The disposal container will include outer and inner cylinders, outer and inner cylinder lids, and may include a canister guide. An exterior label will provide a means by

  3. BNGS B valve packing program

    International Nuclear Information System (INIS)

    Cumming, D.

    1995-01-01

    The Bruce B Valve Packing Program began in 1987. The early history and development were presented at the 1992 International CANDU Maintenance conference. This presentation covers the evolution of the Bruce B Valve Packing Program over the period 1992 to 1995. (author)

  4. Risk Factors for Late Aortic Valve Dysfunction After the David V Valve-Sparing Root Replacement.

    Science.gov (United States)

    Esaki, Jiro; Leshnower, Bradley G; Binongo, Jose N; Lasanajak, Yi; McPherson, LaRonica; Guyton, Robert A; Chen, Edward P

    2017-11-01

    Valve-sparing root replacement (VSRR) is an established therapy for aortic root pathology. However, late aortic valve dysfunction requiring reoperation remains a primary concern of this procedure. This study examines risk factors for late aortic insufficiency (AI) and aortic stenosis (AS) after David V VSRR. A retrospective review from 2005 to 2015 at a US academic center identified 282 patients who underwent VSRR. Cox proportional hazards regression analysis was used to identify risk factors for late AI and AS after VSRR. The mean age was 46.4 years. Sixty-four patients (22.7%) had bicuspid valves, and 41 patients (14.5%) had Marfan syndrome. The incidence of reoperations was 27 (9.6%), and 42 cases (14.9%) presented with acute type A dissection. Operative mortality was 8 (2.8%). Seven-year survival was 90.9%. Seven-year cumulative incidence of reoperation, greater than 2+ AI and greater than moderate AS were 3.1%, 2.2%, and 0.8%, respectively. Multivariable analysis showed aortic root size 55 mm or larger (hazard ratio 3.44, 95% confidence interval: 1.27 to 9.29, p = 0.01) to be a risk factor for late AI whereas bicuspid valve (hazard ratio 16.07, 95% confidence interval: 3.12 to 82.68, p = 0.001) and cusp repair were found to be risk factors (hazard ratio 5.91, 95% confidence interval: 1.17 to 29.86, p = 0.03) for late AS. Valve-sparing root replacement can be performed with low operative risk and good overall long-term survival even in complex clinical settings. Durable valve function can be expected; however, aortic root size 55 cm or more, bicuspid valve anatomy, and cusp repair represent independent risk factors for late aortic valve dysfunction after these procedures. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  5. Aortic valve replacement in octogenarians

    Directory of Open Access Journals (Sweden)

    Dark John H

    2007-07-01

    Full Text Available Abstract Background and Aims As our population ages and life expectancy increases the number of people aged over 80 and more referred for cardiac surgery is growing. This study sought to identify the outcome of aortic valve replacement (AVR in octogenarians. Methods 68 patients aged 80 years or more underwent AVR at the Freeman Hospital, between April 2001 and April 2004. A retrospective review of the notes and outcomes from the patients' GP and the NHS strategic tracking service was performed. 54% (37 underwent isolated AVR whilst 46% (31 underwent combined AVR and CABG. Results Follow up was 100% complete. The mean age was 83.1 ± s.d. 2.9 years, a mean gradient of 83 ± s.d. 31 mmHg and mean AVA of 0.56 cm2. The mean additive EuroSCORE was 8.6 ± s.d. 1.2, the logistic EuroSCORE mean 12.0 ± s.d. 5.9. In hospital 30 day mortality was 13 %. Survival was 80% at 1 year and 78% at 2 years. Median follow up was for 712 days. Stepwise logistic regression identified chronic obstructive airways disease as an independent predictor of mortality (p Conclusion Our study demonstrates that the operative mortality for AVR in the over eighties is good, whilst the mid to long term outcome is excellent There is a very low attrition rate with those undergoing the procedure living as long than their age matched population. This study confirms AVR is a safe, acceptable treatment for octogenarians with excellent mid term outcomes.

  6. A review of digital radiography technology for valve inspection

    International Nuclear Information System (INIS)

    Stoev, K.; Guerout, F.M.; Horn, D.

    2008-01-01

    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)

  7. Disposal of radioactive wastes

    International Nuclear Information System (INIS)

    Blomeke, J.O.

    1979-01-01

    Radioactive waste management and disposal requirements options available are discussed. The possibility of beneficial utilization of radioactive wastes is covered. Methods of interim storage of transuranium wastes are listed. Methods of shipment of low-level and high-level radioactive wastes are presented. Various methods of radioactive waste disposal are discussed

  8. Analysis of Mitral Valve Replacement Outcomes is Enhanced by Meaningful Clinical Use of Electronic Health Records

    Science.gov (United States)

    Chen, John C; Pfeffer, Thomas; Johnstone, Shelley; Chen, Yuexin; Kiley, Mary-Lou; Richter, Richard; Lee, Hon

    2013-01-01

    Objective: Cardiac surgical mortality has improved during the last decade despite the aging of the population. An integrated US health plan developed a heart valve registry to track outcomes and complications of heart valve operations. This database was used for longitudinal evaluation of mitral valve (MV) outcomes from 1999 to 2008 at four affiliated hospitals. Methods: We identified 3130 patients in the Apollo database who underwent 3180 initial MV procedures. Internal administrative and Social Security Administration databases were merged to determine survival rates. Electronic health records were searched to ascertain demographics, comorbidities, and postoperative complications. Cox regression was used to evaluate mean survival and identify risk factors. Results: The procedures included 1160 mechanical valve replacements, 1159 tissue valve replacements, and 861 annuloplasties. The mean age of patients undergoing these procedures was 58 ± 11 years, 69 ± 12 years, and 62 ± 12 years, respectively. Mean survival was 8.9 ± 0.1 years for mechanical valve replacement, 7.0 ± 0.1 years for tissue valve replacement, and 7.7 ± 0.1 years for annuloplasty. Early in the study, there was a preference for implanting mechanical MVs. Beginning in 2003, more patients received tissue valve replacements rather than mechanical valves. Over time, there was an increasing trend of annuloplasty. Cox regression analysis identified the following risk factors for increased ten-year mortality: tissue valve implantation; advanced age; female sex; nonelective, nonisolated procedure; diabetes; postoperative use of banked blood products; previous cardiovascular intervention; dialysis; and longer perfusion time. Hospital location, reoperation, preoperative anticoagulation, and cardiogenic shock were not statistically significant risk factors. Conclusions: When controlling for other risk factors, we observed a lower long-term survival rate for tissue valve replacement compared with

  9. Experience with valves for PHWR reactors

    International Nuclear Information System (INIS)

    Narayan, K.; Mhetre, S.G.

    1977-01-01

    Material specifications and inspection and testing requirements of the valves meant for use in nuclear reactors are mentioned. In the heavy water systems (both primary and moderator) of a PHWR type reactor, the valves used are gate valves, globe valves, diaphragm valves, butterfly valves, check valves and relief valves. Their locations and functions they perform in the Rajasthan Atomic Power Station Unit-1 are described. Experience with them is given. The major problems encountered with them have been : (1) leakage from the stem seals and body bonnet joint, (2) leakage due to failure of diaphragm and/or washout of the packing and (3) malfunctioning. Measures taken to solve these are discussed. Finally a mention has been made of improved versions of valves, namely, metal diaphragm valve and inverted relief valve. (M.G.B.)

  10. Reoperation for non-structural valvular dysfunction caused by pannus ingrowth in aortic valve prosthesis.

    Science.gov (United States)

    Oh, Se Jin; Park, Samina; Kim, Jun Sung; Kim, Kyung-Hwan; Kim, Ki Bong; Ahn, Hyuk

    2013-07-01

    The authors' clinical experience is presented of non-structural valvular dysfunction of the prosthetic aortic valve caused by pannus ingrowth during the late postoperative period after previous heart valve surgery. Between January 1999 and April 2012, at the authors' institution, a total of 33 patients underwent reoperation for increased mean pressure gradient of the prosthetic aortic valve. All patients were shown to have pannus ingrowth. The mean interval from the previous operation was 16.7 +/- 4.3 years, and the most common etiology for the previous aortic valve replacement (AVR) was rheumatic valve disease. The mean effective orifice area index (EOAI) of the previous prosthetic valve was 0.97 +/- 0.11 cm2/m2, and the mean pressure gradient on the aortic prosthesis before reoperation was 39.1 +/- 10.7 mmHg. Two patients (6.1%) died in-hospital, and late death occurred in six patients (18.2%). At the first operation, 30 patients underwent mitral or tricuspid valve surgery as a concomitant procedure. Among these operations, mitral valve replacement (MVR) was combined in 24 of all 26 patients with rheumatic valve disease. Four patients underwent pannus removal only while the prosthetic aortic valve was left in place. The mean EOAI after reoperation was significantly increased to 1.16 +/- 0.16 cm2/m2 (p pannus ingrowth was shown in patients with a small EOAI of the prosthetic aortic valve and combined MVR for rheumatic disease. As reoperation for pannus overgrowth showed good clinical outcomes, an aggressive resection of pannus and repeated AVR should be considered in symptomatic patients to avoid the complications of other cardiac diseases.

  11. Equity and nuclear waste disposal

    International Nuclear Information System (INIS)

    Shrader-Frechette, K.

    1994-01-01

    Following the recommendations of the US National Academy of Sciences and the mandates of the 1987 Nuclear Waste Policy Amendments Act, the US Department of Energy has proposed Yucca Mountain, Nevada as the site of the world's first permanent repository for high-level nuclear waste. The main justification for permanent disposal (as opposed to above-ground storage) is that it guarantees safety by means of waste isolation. This essay argues, however, that considerations of equity (safer for whom?) undercut the safety rationale. The article surveys some prima facie arguments for equity in the distribution of radwaste risks and then evaluates four objections that are based, respectively, on practicality, compensation for risks, scepticism about duties to future generations, and the uranium criterion. The conclusion is that, at least under existing regulations and policies, permanent waste disposal is highly questionable, in part, because it fails to distribute risk equitably or to compensate, in full, for this inequity

  12. Geological Disposal of Radioactive Waste

    International Nuclear Information System (INIS)

    Dody, A.; Klein, Ben; David, O.

    2014-01-01

    Disposal of radioactive waste imposes complicated constrains on the regulator to ensure the isolation of radioactive elements from the biosphere. The IAEA (1995) states that T he objective of radioactive waste management is to deal with radioactive waste in a manner that protects human health and the environment now and the future without imposing undue burdens on future generation . The meaning of this statement is that the operator of the waste disposal facilities must prove to the regulator that in routine time and in different scenarios the dose rate to the public will not exceed 0.3 mSv/y in the present and in the future up to 10,000 years

  13. The influence of Marfans and bicuspid valves on outcomes following aortic valve reimplantation.

    Science.gov (United States)

    Martín, Carlos E; García Montero, Carlos; Serrano, Santiago-Fiz; González, Ana; Mingo, Susana; Moñivas, Vanessa; Centeno, Jorge; Forteza, Alberto

    2017-10-01

    We analyzed our early and midterm results with aortic valve reimplantation surgery to determine the influence of Marfan syndrome and bicuspid valves on outcomes with this technique. Between March 2004 and December 2015, 267 patients underwent aortic valve reimplantation operations. The mean diameter of the sinuses of Valsalva was 50 ± 3 mm and moderate/severe aortic regurgitation was present in 34.4% of these patients. A bicuspid aortic valve was present in 21% and 40% had Marfan syndrome. Overall 30-day mortality was 0.37% (1/267). Mean follow-up was 59.7 ± 38.7 months. Overall survival at 1, 3, and 5 years was 98 ± 8%, 98 ± 1%, and 94 ± 2%, respectively. Freedom from reoperation and aortic regurgitation >II was 99 ± 5%, 98 ± 8%, 96.7 ± 8%, and 99 ± 6%, 98 ± 1%, 98 ± 1%, respectively at 1, 3, and 5 years follow-up, with no differences between Marfan and bicuspid aortic valve groups. (p = 0.94 and p = 0.96, respectively). No endocarditis or thromboembolic complications were documented, and 93.6% of the patients did not receive any anticoagulation therapy. The reimplantation technique for aortic root aneurysms is associated with excellent clinical and functional outcomes at short and mid-term follow-up. © 2017 Wiley Periodicals, Inc.

  14. Proving test on the reliability for nuclear valves

    International Nuclear Information System (INIS)

    Kajiyama, Yasuo; Tashiro, Hisao; Uga, Takeo; Maeda, Shunichi.

    1986-01-01

    Since valves are the most common components, they could be the most frequent causes of troubles in nuclear power plants. This proving test, therefore, has an important meaning to examine and verify the reliability of various valves under simulating conditions of abnormal and transient operations of the nuclear power plant. The test was performed mainly for the various types and pressure ratings of valves which were used in the primary and secondary systems in BWR and PWR nuclear power plants and which had major operating or safety related functions in those nuclear power plants. The results of the proving test, confirmed for more than four years, showed relatively favourable performance of the tested valves. It is concluded that performances of valves including operability, seat sealing and structural integrity were proved under the thermal cycling, vibration and pipe reaction load conditions. Operating functions during and after accident such as loss of coolant accident were satisfactory. From these results, it was considered that the purpose of this proving test was satisfactorily fulfilled. Several data accumulated by the test would be useful to get better reliability if it was evaluated with the actually experienced data of valves in the nuclear power plants. (Nogami, K.)

  15. Trabeculectomy versus Ahmed Glaucoma Valve implantation in neovascular glaucoma

    Science.gov (United States)

    Shen, Christopher C; Salim, Sarwat; Du, Haiming; Netland, Peter A

    2011-01-01

    Purpose: To compare surgical outcomes in neovascular glaucoma patients who underwent trabeculectomy with mitomycin C versus Ahmed Glaucoma Valve implantation. Patients and methods: This was a retrospective comparative case series. We reviewed 40 eyes of 39 patients with underlying diagnosis of neovascular glaucoma, divided into two groups: Ahmed Glaucoma Valve (N = 20) and trabeculectomy with mitomycin C (N = 20). Surgical success was defined as 6 mm Hg ≤ intraocular pressure ≤21 mm Hg, with or without the use of glaucoma medications, with no further glaucoma surgery, and light perception or better vision. Early postoperative hypotony was defined as intraocular pressure Ahmed Glaucoma Valve group and 25 months (6–77 months) for the trabeculectomy group. Although the mean number of postoperative intraocular pressure-lowering medications was significantly higher in the trabeculectomy group compared with the Ahmed Glaucoma Valve group at 3 and 6 month time points, there was no statistically significant difference at any other time point. There was no statistically significant difference between both groups in postoperative visual acuity and intraocular pressure. Success was 70% and 65% at 1 year and 60% and 55% at 2 years after Ahmed Glaucoma Valve and trabeculectomy, respectively. Kaplan–Meier survival curve analysis showed no significant difference in success between the two groups (P = 0.815). Hyphema was the most common complication in both groups. Conclusion: We found similar results after trabeculectomy with mitomycin C and Ahmed Glaucoma Valve implantation in eyes with neovascular glaucoma. PMID:21468334

  16. Postoperative Outcomes of Mitral Valve Repair for Mitral Restenosis after Percutaneous Balloon Mitral Valvotomy

    Directory of Open Access Journals (Sweden)

    Seong Lee

    2015-10-01

    Full Text Available Background: There have been a number of studies on mitral valve replacement and repeated percutaneous mitral balloon valvotomy for mitral valve restenosis after percutaneous mitral balloon valvotomy. However, studies on mitral valve repair for these patients are rare. In this study, we analyzed postoperative outcomes of mitral valve repair for mitral valve restenosis after percutaneous mitral balloon valvotomy. Methods: In this study, we assessed 15 patients (mean age, 47.7±9.7 years; 11 female and 4 male who underwent mitral valve repair between August 2008 and March 2013 for symptomatic mitral valve restenosis after percutaneous mitral balloon valvotomy. The mean interval between the initial percutaneous mitral balloon valvotomy and the mitral valve repair was 13.5±7 years. The mean preoperative Wilkins score was 9.4±2.6. Results: The mean mitral valve area obtained using planimetry increased from 1.16±0.16 cm2 to 1.62±0.34 cm2 (p=0.0001. The mean pressure half time obtained using Doppler ultrasound decreased from 202.4±58.6 ms to 152±50.2 ms (p=0.0001. The mean pressure gradient obtained using Doppler ultrasound decreased from 9.4±4.0 mmHg to 5.8±1.5 mmHg (p=0.0021. There were no early or late deaths. Thromboembolic events or infective endocarditis did not occur. Reoperations such as mitral valve repair or mitral valve replacement were not performed during the follow-up period (39±16 months. The 5-year event-free survival was 56.16% (95% confidence interval, 47.467–64.866. Conclusion: On the basis of these results, we could not conclude that mitral valve repair could be an alternative for patients with mitral valve restenosis after percutaneous balloon mitral valvotomy. However, some patients presented with results similar to those of mitral valve replacement. Further studies including more patients with long-term follow-up are necessary to determine the possibility of this application of mitral valve repair.

  17. Analysis of fatigue reliability for high temperature and high pressure multi-stage decompression control valve

    Science.gov (United States)

    Yu, Long; Xu, Juanjuan; Zhang, Lifang; Xu, Xiaogang

    2018-03-01

    Based on stress-strength interference theory to establish the reliability mathematical model for high temperature and high pressure multi-stage decompression control valve (HMDCV), and introduced to the temperature correction coefficient for revising material fatigue limit at high temperature. Reliability of key dangerous components and fatigue sensitivity curve of each component are calculated and analyzed by the means, which are analyzed the fatigue life of control valve and combined with reliability theory of control valve model. The impact proportion of each component on the control valve system fatigue failure was obtained. The results is shown that temperature correction factor makes the theoretical calculations of reliability more accurate, prediction life expectancy of main pressure parts accords with the technical requirements, and valve body and the sleeve have obvious influence on control system reliability, the stress concentration in key part of control valve can be reduced in the design process by improving structure.

  18. Prosthetic valve endocarditis after transcatheter aortic valve implantation

    DEFF Research Database (Denmark)

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

    2015-01-01

    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......%) 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...

  19. Aortic root surgery in Marfan syndrome: Comparison of aortic valve-sparing reimplantation versus composite grafting.

    Science.gov (United States)

    Karck, Matthias; Kallenbach, Klaus; Hagl, Christian; Rhein, Christine; Leyh, Rainer; Haverich, Axel

    2004-02-01

    The objective of this study was to compare the results of aortic valve-sparing reimplantation and aortic root replacement with mechanical valve conduits in patients with Marfan syndrome undergoing operation for aortic root aneurysms. Patients and methods Between March 1979 and April 2002, 119 patients with clinical evidence of Marfan syndrome underwent composite graft replacement with mechanical valve conduits (n = 74) or aortic valve-sparing reimplantation according to David (n = 45). The underlying causes were aortic dissection type A (43 patients) and aneurysms (76 patients). Patients undergoing aortic valve reimplantation were younger compared with patients undergoing composite grafting (28 vs 35 years, P =.002) and had longer intraoperative aortic crossclamp times (125 vs 78 minutes, P valve reimplantation (P =.15). Mean follow-up was 30 months for patients undergoing aortic valve reimplantation and 114 months for patients undergoing composite grafting. Freedom from reoperation and death after 5 years postoperatively was 92% and 89% in patients undergoing composite grafting and 84% and 96% in patients undergoing aortic valve reimplantation (P =.31; P =.54), respectively. Thromboembolic complications or late postoperative bleeding occurred in 17 patients undergoing composite grafting, and an early postoperative event occurred in 1 patient undergoing aortic valve reimplantation. The results of aortic valve reimplantation and composite grafting of the aortic valve and ascending aorta with mechanical valve conduits are similar with regard to early and mid-term postoperative mortality and to the incidence of late reoperations in patients with Marfan syndrome. The low risk of thromboembolic or bleeding complications favors aortic valve reimplantation in these patients.

  20. Anesthetic Management and Complications of Percutaneous Aortic Valve Implantation

    Directory of Open Access Journals (Sweden)

    Tailur Alberto Grando

    2013-05-01

    Full Text Available Background and objective: Aortic stenosis is a highly prevalent and life-threatening disease. In elderly patients with comorbidities, percutaneous valve implantation is an option. The aim of the study was to describe the anesthetic management and complications of general anesthesia Method: Case series with 30-day and 24-month follow-ups after implantation of the CoreValve device performed at the Institute of Cardiology/University Foundation of Cardiology between December 2008 and January 2012. The patients underwent general anesthesia monitored with mean arterial pressure (PAM, electrocardiogram (ECG, pulse oximetry, capnography, transesophageal echocardiography, thermometry, and transvenous pacemaker. Results: Twenty-eight patients, mean age 82.46 years, 20.98% mean EuroSCORE, functional class III/IV, successfully underwent valve implantation. Nine patients required permanent pacemaker implantation. During follow-up, two patients died: one during surgery due to LV perforation and the other on the third day of unknown causes. At 24 months, one patient diagnosed with multiple myeloma died. This anesthetic technique proved to be safe. Conclusion: The initial experience with percutaneous aortic valve implantation under general anesthesia has proven to be safe and effective, with no significant anesthetic complications during this procedure. Keywords: Aesthesia, General, Cardiac Surgical Procedures, Aortic Valve Stenosis, Aged.

  1. Aerodynamic instabilities in governing valves of steam turbines

    International Nuclear Information System (INIS)

    Richard, J.M.; Pluviose, M.

    1991-01-01

    The capacity of a.c. turbogenerators in a Pressurized Water Reactor (PWR) is regulated by means of governing valves located at the inlet of the high-pressure turbine. The conditions created in these valves (due to the throttling of the steam) involve the generation of a jet structure, possibly supersonic. Aerodynamic instabilities could potentially excite the mechanical structure. These aerodynamic phenomena are studied in this paper by means of a two-dimensional numerical model. Viscous effects are taken into account with heuristic criteria on separation and reattachment. Detailed experimental analysis of the flow behaviour is compared with the numerical prediction of stability limits. (Author)

  2. Disposal of radioactive waste

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1960-01-15

    The problem of disposal can be tackled in two ways: the waste can be diluted and dispersed so that the radiation to which any single individual would be subjected would be negligible, or it can be concentrated and permanently isolated from man and his immediate environment. A variety of methods for the discharge of radioactive waste into the ground were described at the Monaco conference. They range from letting liquid effluent run into pits or wells at appropriately chosen sites to the permanent storage of high activity material at great depth in geologically suitable strata. Another method discussed consists in the incorporation of high level fission products in glass which is either buried or stored in vaults. Waste disposal into rivers, harbours, outer continental shelves and the open sea as well as air disposal are also discussed. Many of the experts at the Monaco conference were of the view that most of the proposed, or actually applied, methods of waste disposal were compatible with safety requirements. Some experts, felt that certain of these methods might not be harmless. This applied to the possible hazards of disposal in the sea. There seemed to be general agreement, however, that much additional research was needed to devise more effective and economical methods of disposal and to gain a better knowledge of the effects of various types of disposal operations, particularly in view of the increasing amounts of waste material that will be produced as the nuclear energy industry expands

  3. Transcatheter aortic valve implantation for failing surgical aortic bioprosthetic valve: from concept to clinical application and evaluation (part 2).

    Science.gov (United States)

    Piazza, Nicolo; Bleiziffer, Sabine; Brockmann, Gernot; Hendrick, Ruge; Deutsch, Marcus-André; Opitz, Anke; Mazzitelli, Domenico; Tassani-Prell, Peter; Schreiber, Christian; Lange, Rüdiger

    2011-07-01

    This study sought to review the acute procedural outcomes of patients who underwent transcatheter aortic valve (TAV)-in-surgical aortic valve (SAV) implantation at the German Heart Center, Munich, and to summarize the existing literature on TAV-in-SAV implantation (n = 47). There are several case reports and small case series describing transcatheter aortic valve implantation for a failing surgical aortic valve bioprosthesis (TAV-in-SAV implantation). From January 2007 to March 2011, 20 out of 556 patients underwent a TAV-in-SAV implantation at the German Heart Center Munich. Baseline characteristics and clinical outcome data were prospectively entered into a dedicated database. The mean patient age was 75 ± 13 years, and the mean logistic European System for Cardiac Operative Risk Evaluation and Society of Thoracic Surgeons' Risk Model scores were 27 ± 13% and 7 ± 4%, respectively. Of the 20 patients, 14 had stented and 6 had stentless surgical bioprostheses. Most cases (12 of 20) were performed via the transapical route using a 23-mm Edwards Sapien prosthesis (Edwards Lifesciences, Irvine, California). Successful implantation of a TAV in a SAV with the patient leaving the catheterization laboratory alive was achieved in 18 of 20 patients. The mean transaortic valve gradient was 20.0 ± 7.5 mm Hg. None-to-trivial, mild, and mild-to-moderate paravalvular aortic regurgitation was observed in 10, 6, and 2 patients, respectively. We experienced 1 intraprocedural death following pre-implant balloon aortic valvuloplasty ("stone heart") and 2 further in-hospital deaths due to myocardial infarction. TAV-in-SAV implantation is a safe and feasible treatment for high-risk patients with failing aortic bioprosthetic valves and should be considered as part of the armamentarium in the treatment of aortic bioprosthetic valve failure. Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  4. Energy dynamics of the intraventricular vortex after mitral valve surgery.

    Science.gov (United States)

    Nakashima, Kouki; Itatani, Keiichi; Kitamura, Tadashi; Oka, Norihiko; Horai, Tetsuya; Miyazaki, Shohei; Nie, Masaki; Miyaji, Kagami

    2017-09-01

    Mitral valve morphology after mitral valve surgery affects postoperative intraventricular flow patterns and long-term cardiac performance. We visualized ventricular flow by echocardiography vector flow mapping (VFM) to reveal the impact of different mitral valve procedures. Eleven cases of mechanical mitral valve replacement (nine in the anti-anatomical and two in the anatomical position), three bioprosthetic mitral valve replacements, and four mitral valve repairs were evaluated. The mean age at the procedure was 57.4 ± 17.8 year, and the echocardiography VFM in the apical long-axis view was performed 119.9 ± 126.7 months later. Flow energy loss (EL), kinetic pressure (KP), and the flow energy efficiency ratio (EL/KP) were measured. The cases with MVR in the anatomical position and with valve repair had normal vortex directionality ("Clockwise"; N = 6), whereas those with MVR in the anti-anatomical position and with a bioprosthetic mitral valve had the vortex in the opposite direction ("Counterclockwise"; N = 12). During diastole, vortex direction had no effect on EL ("Clockwise": 0.080 ± 0.025 W/m; "Counterclockwise": 0.083 ± 0.048 W/m; P = 0.31) or KP ("Clockwise": 0.117 ± 0.021 N; "Counterclockwise": 0.099 ± 0.057 N; P = 0.023). However, during systole, the EL/KP ratio was significantly higher in the "Counterclockwise" vortex than that in the "Clockwise" vortex (1.056 ± 0.463 vs. 0.617 ± 0.158; P = 0.009). MVP and MVR with a mechanical valve in the anatomical position preserve the physiological vortex, whereas MVR with a mechanical valve in the anti-anatomical position and a bioprosthetic mitral valve generate inefficient vortex flow patterns, resulting in a potential increase in excessive cardiac workload.

  5. 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.

  6. Cavitation guide for control valves

    International Nuclear Information System (INIS)

    Tullis, J.P.

    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

  7. Characteristic analysis of servo valve

    International Nuclear Information System (INIS)

    Ko, J. H.; Ryu, D. R.; Lee, J. H.; Kim, Y. S.; Na, J. C.; Kim, D. S.

    2008-01-01

    Electro-pneumatic servo valve is an electro-mechanical device which converts electric signals into a proper pneumatic flow rate or pressure. In order to improve the overall performance of pneumatic servo systems, electro-pneumatic servo valves are required, which have fast dynamic characteristics, no air leakage at a null point, and can be fabricated at a low-cost. The first objective of this research is to design and to fabricate a new electro-pneumatic servo valve which satisfies the above-mentioned requirements. In order to design the mechanism of the servo valve optimally, the flow inside the valve depending upon the position of spool was analyzed variously, and on the basis of such analysis results, the valve mechanism, which was formed by combination of the spool and the sleeve, was designed and manufactured. And a tester for conducting an overall performance test was designed and manufactured, and as a result of conducting the flow rate test, the pressure test and the frequency test on the developed pneumatic servo valve

  8. Development and Characterization a Single-Active-Chamber Piezoelectric Membrane Pump with Multiple Passive Check Valves

    Directory of Open Access Journals (Sweden)

    Ronghui Zhang

    2016-12-01

    Full Text Available In order to prevent the backward flow of piezoelectric pumps, this paper presents a single-active-chamber piezoelectric membrane pump with multiple passive check valves. Under the condition of a fixed total number of passive check valves, by means of changing the inlet valves and outlet valves’ configuration, the pumping characteristics in terms of flow rate and backpressure are experimentally investigated. Like the maximum flow rate and backpressure, the testing results show that the optimal frequencies are significantly affected by changes in the number inlet valves and outlet valves. The variation ratios of the maximum flow rate and the maximum backpressure are up to 66% and less than 20%, respectively. Furthermore, the piezoelectric pump generally demonstrates very similar flow rate and backpressure characteristics when the number of inlet valves in one kind of configuration is the same as that of outlet valves in another configuration. The comparison indicates that the backflow from the pumping chamber to inlet is basically the same as the backflow from the outlet to the pumping chamber. No matter whether the number of inlet valves or the number of outlet valves is increased, the backflow can be effectively reduced. In addition, the backpressure fluctuation can be significantly suppressed with an increase of either inlet valves or outlet valves. It also means that the pump can prevent the backflow more effectively at the cost of power consumption. The pump is very suitable for conditions where more accurate flow rates are needed and wear and fatigue of check valves often occur.

  9. Developments in mechanical heart valve prosthesis

    Indian Academy of Sciences (India)

    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 ...

  10. Butterfly valve torque prediction methodology

    International Nuclear Information System (INIS)

    Eldiwany, B.H.; Sharma, V.; Kalsi, M.S.; Wolfe, K.

    1994-01-01

    As part of the Motor-Operated Valve (MOV) Performance Prediction Program, the Electric Power Research Institute has sponsored the development of methodologies for predicting thrust and torque requirements of gate, globe, and butterfly MOVs. This paper presents the methodology that will be used by utilities to calculate the dynamic torque requirements for butterfly valves. The total dynamic torque at any disc position is the sum of the hydrodynamic torque, bearing torque (which is induced by the hydrodynamic force), as well as other small torque components (such as packing torque). The hydrodynamic torque on the valve disc, caused by the fluid flow through the valve, depends on the disc angle, flow velocity, upstream flow disturbances, disc shape, and the disc aspect ratio. The butterfly valve model provides sets of nondimensional flow and torque coefficients that can be used to predict flow rate and hydrodynamic torque throughout the disc stroke and to calculate the required actuation torque and the maximum transmitted torque throughout the opening and closing stroke. The scope of the model includes symmetric and nonsymmetric discs of different shapes and aspects ratios in compressible and incompressible fluid applications under both choked and nonchoked flow conditions. The model features were validated against test data from a comprehensive flowloop and in situ test program. These tests were designed to systematically address the effect of the following parameters on the required torque: valve size, disc shapes and disc aspect ratios, upstream elbow orientation and its proximity, and flow conditions. The applicability of the nondimensional coefficients to valves of different sizes was validated by performing tests on 42-in. valve and a precisely scaled 6-in. model. The butterfly valve model torque predictions were found to bound test data from the flow-loop and in situ testing, as shown in the examples provided in this paper

  11. [Periodontal microbiota and microorganisms isolated from heart valves in patients undergoing valve replacement surgery in a clinic in Cali, Colombia].

    Science.gov (United States)

    Moreno, Sandra; Parra, Beatriz; Botero, Javier E; Moreno, Freddy; Vásquez, Daniel; Fernández, Hugo; Alba, Sandra; Gallego, Sara; Castillo, Gilberto; Contreras, Adolfo

    2017-12-01

    Periodontitis is an infectious disease that affects the support tissue of the teeth and it is associated with different systemic diseases, including cardiovascular disease. Microbiological studies facilitate the detection of microorganisms from subgingival and cardiovascular samples. To describe the cultivable periodontal microbiota and the presence of microorganisms in heart valves from patients undergoing valve replacement surgery in a clinic in Cali. We analyzed 30 subgingival and valvular tissue samples by means of two-phase culture medium, supplemented blood agar and trypticase soy agar with antibiotics. Conventional PCR was performed on samples of valve tissue. The periodontal pathogens isolated from periodontal pockets were: Fusobacterium nucleatum (50%), Prevotella intermedia/ nigrescens (40%), Campylobacter rectus (40%), Eikenella corrodens (36.7%), Gram negative enteric bacilli (36.7%), Porphyromonas gingivalis (33.3%), and Eubacterium spp. (33.3%). The pathogens isolated from the aortic valve were Propionibacterium acnes (12%), Gram negative enteric bacilli (8%), Bacteroides merdae (4%), and Clostridium bifermentans (4%), and from the mitral valve we isolated P. acnes and Clostridium beijerinckii. Conventional PCR did not return positive results for oral pathogens and bacterial DNA was detected only in two samples. Periodontal microbiota of patients undergoing surgery for heart valve replacement consisted of species of Gram-negative bacteria that have been associated with infections in extraoral tissues. However, there is no evidence of the presence of periodontal pathogens in valve tissue, because even though there were valve and subgingival samples positive for Gram-negative enteric bacilli, it is not possible to maintain they corresponded to the same phylogenetic origin.

  12. Disposal of radioactive wastes

    International Nuclear Information System (INIS)

    Dlouhy, Z.

    1982-01-01

    This book provides information on the origin, characteristics and methods of processing of radioactive wastes, as well as the philosophy and practice of their storage and disposal. Chapters are devoted to the following topics: radioactive wastes, characteristics of radioactive wastes, processing liquid and solid radioactive wastes, processing wastes from spent fuel reprocessing, processing gaseous radioactive wastes, fixation of radioactive concentrates, solidification of high-level radioactive wastes, use of radioactive wastes as raw material, radioactive waste disposal, transport of radioactive wastes and economic problems of radioactive wastes disposal. (C.F.)

  13. Subseabed disposal safety analysis

    International Nuclear Information System (INIS)

    Koplick, C.M.; Kabele, T.J.

    1982-01-01

    This report summarizes the status of work performed by Analytic Sciences Corporation (TASC) in FY'81 on subseabed disposal safety analysis. Safety analysis for subseabed disposal is divided into two phases: pre-emplacement which includes all transportation, handling, and emplacement activities; and long-term (post-emplacement), which is concerned with the potential hazard after waste is safely emplaced. Details of TASC work in these two areas are provided in two technical reports. The work to date, while preliminary, supports the technical and environmental feasibility of subseabed disposal of HLW

  14. The Neopuff's PEEP valve is flow sensitive.

    LENUS (Irish Health Repository)

    Hawkes, Colin Patrick

    2012-01-31

    AIM: The current recommendation in setting up the Neopuff is to use a gas flow of 5-15 L\\/min. We investigated if the sensitivity of the positive end expiratory pressure (PEEP) valve varies at different flow rates within this range. METHODS: Five Neopuffs were set up to provide a PEEP of 5 cm H(2) O. The number of clockwise revolutions to complete occlusion of the PEEP valve and the mean and range of pressures at each quarter clockwise revolution were recorded at gas flow rates between 5 and 15 L\\/min. Results: At 5, 10 and 15 L\\/min, 0.5, 1.7 and 3.4 full clockwise rotations were required to completely occlude the PEEP valve, and pressures rose from 5 to 11.4, 18.4 and 21.5 cm H(2) O, respectively. At a flow rate of 5 L\\/min, half a rotation of the PEEP dial resulted in a rise in PEEP from 5 to 11.4cm H(2) O. At 10 L\\/min, half a rotation resulted in a rise from 5 to 7.7cm H(2) O, and at 15 L\\/min PEEP rose from 5 to 6.8cm H(2) O. CONCLUSION: Users of the Neopuff should be aware that the PEEP valve is more sensitive at lower flow rates and that half a rotation of the dial at 5 L\\/min gas flow can more than double the PEEP.

  15. Transcatheter Mitral Valve-in-Ring Implantation

    LENUS (Irish Health Repository)

    Tanner, RE

    2018-05-01

    Failed surgical mitral valve repair using an annuloplasty ring has traditionally been treated with surgical valve replacement or repair1. For patients at high risk for repeat open heart surgery, placement of a trans-catheter aortic valve (i.e., TAVI valve) within the mitral ring (i.e., Mitral-Valve-in-Ring, MViR) has emerged as a novel alternative treatment strategy2-5 . We describe our experience of a failed mitral valve repair that was successfully treated with a TAVI valve delivered via the trans-septal approach, and summarise the data relating to this emerging treatment strategy.

  16. Valve leakage inspection testing and maintenance process

    International Nuclear Information System (INIS)

    Aikin, J.A.; Reinwald, J.W.; Kittmer, C.A.

    1991-01-01

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

  17. The disposal of radioactive waste on land

    Energy Technology Data Exchange (ETDEWEB)

    None

    1957-09-01

    A committee of geologists and geophysicists was established by the National Academy of Sciences-National Research Council at the request of the Atomic Energy Commission to consider the possibilities of disposing of high level radioactive wastes in quantity within the continental limits of the United States. The group was charged with assembling the existing geologic information pertinent to disposal, delineating the unanswered problems associated with the disposal schemes proposed, and point out areas of research and development meriting first attention; the committee is to serve as continuing adviser on the geological and geophysical aspects of disposal and the research and development program. The Committee with the cooperation of the Johns Hopkins University organized a conference at Princeton in September 1955. After the Princeton Conference members of the committee inspected disposal installations and made individual studies. Two years consideration of the disposal problems leads to-certain general conclusions. Wastes may be disposed of safely at many sites in the United States but, conversely, there are many large areas in which it is unlikely that disposal sites can be found, for example, the Atlantic Seaboard. Disposal in cavities mined in salt beds and salt domes is suggested as the possibility promising the most practical immediate solution of the problem. In the future the injection of large volumes of dilute liquid waste into porous rock strata at depths in excess of 5,000 feet may become feasible but means of rendering, the waste solutions compatible with the mineral and fluid components of the rock must first be developed. The main difficulties, to the injection method recognized at present are to prevent clogging of pore space as the solutions are pumped into the rock and the prediction or control of the rate and direction of movement.

  18. Microbial reduction of SO{sub 2} and NO{sub x} as a means of by-product recovery/disposal from regenerable processes for the desulfurization of flue gas. Technical progress report, September 11, 1992--December 11, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Sublette, K.L.

    1992-12-31

    With the continual increase in the utilization of high sulfur and high nitrogen containing fossil fuels, the release of airborne pollutants into the environment has become a critical problem. The fuel sulfur is converted to SO{sub 2} during combustion. Fuel nitrogen and a fraction of the nitrogen from the combustion air are converted to nitric oxide and nitrogen dioxide, NO{sub x}. For the past five years Combustion Engineering (now Asea Brown Boveri or ABB) and, since 1986, the University of Tulsa (TU) have been investigating the oxidation of H{sub 2}S by the facultatively anaerobic and autotrophic bacterium Thiobacillus denitrificans and have developed a process, concept for the microbial removal of H{sub 2}S from a gas stream the simultaneous removal of SO{sub 2} and NO by D. desulfuricans and T. denitrificans co-cultures and cultures-in-series was demonstrated. These systems could not be sustained due to NO inhibition of D. desulfuricans. However, a preliminary economic analysis has shown that microbial reduction of SO{sub 2} to H{sub 2}S with subsequent conversion to elemental sulfur by the Claus process is both technically and economically feasible if a less expensive carbon and/or energy source can be found. It has also been demonstrated that T. denitrificans can be grown anaerobically on NO(g) as a terminal electron acceptor with reduction to elemental nitrogen. Microbial reduction of NO{sub x} is a viable process concept for the disposal of concentrated streams of NO{sub x} as may be produced by certain regenerable processes for the removal of SO{sub 2} and NO{sub x} from flue gas.

  19. 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.

  20. 3D printed mitral valve models: affordable simulation for robotic mitral valve repair.

    Science.gov (United States)

    Premyodhin, Ned; Mandair, Divneet; Ferng, Alice S; Leach, Timothy S; Palsma, Ryan P; Albanna, Mohammad Z; Khalpey, Zain I

    2018-01-01

    3D printed mitral valve (MV) models that capture the suture response of real tissue may be utilized as surgical training tools. Leveraging clinical imaging modalities, 3D computerized modelling and 3D printing technology to produce affordable models complements currently available virtual simulators and paves the way for patient- and pathology-specific preoperative rehearsal. We used polyvinyl alcohol, a dissolvable thermoplastic, to 3D print moulds that were casted with liquid platinum-cure silicone yielding flexible, low-cost MV models capable of simulating valvular tissue. Silicone-moulded MV models were fabricated for 2 morphologies: the normal MV and the P2 flail. The moulded valves were plication and suture tested in a laparoscopic trainer box with a da Vinci Si robotic surgical system. One cardiothoracic surgery fellow and 1 attending surgeon qualitatively evaluated the ability of the valves to recapitulate tissue feel through surveys utilizing the 5-point Likert-type scale to grade impressions of the valves. Valves produced with the moulding and casting method maintained anatomical dimensions within 3% of directly 3D printed acrylonitrile butadiene styrene controls for both morphologies. Likert-type scale mean scores corresponded with a realistic material response to sutures (5.0/5), tensile strength that is similar to real MV tissue (5.0/5) and anatomical appearance resembling real MVs (5.0/5), indicating that evaluators 'agreed' that these aspects of the model were appropriate for training. Evaluators 'somewhat agreed' that the overall model durability was appropriate for training (4.0/5) due to the mounting design. Qualitative differences in repair quality were notable between fellow and attending surgeon. 3D computer-aided design, 3D printing and fabrication techniques can be applied to fabricate affordable, high-quality educational models for technical training that are capable of differentiating proficiency levels among users. © The Author 2017

  1. Nuclear fuel waste disposal

    International Nuclear Information System (INIS)

    Merrett, G.J.; Gillespie, P.A.

    1983-07-01

    This report discusses events and processes that could adversely affect the long-term stability of a nuclear fuel waste disposal vault or the regions of the geosphere and the biosphere to which radionuclides might migrate from such a vault

  2. Disposal leachates treatment

    Energy Technology Data Exchange (ETDEWEB)

    Coulomb, I.; Renaud, P. (SITA, 75 - Paris (France)); Courant, P. (FD Conseil, 78 - Gargenville (France)); Manem, J.; Mandra, V.; Trouve, E. (Lyonnaise des Eaux-Dumez, 78 - Le Pecq (France))

    1993-12-01

    Disposal leachates are complex and variable effluents. The use of a bioreactor with membranes, coupled with a reverse osmosis unit, gives a new solution to the technical burying centers. Two examples are explained here.

  3. Safe Disposal of Pesticides

    Science.gov (United States)

    ... Toxics Environmental Information by Location Greener Living Health Land, Waste, and Cleanup Lead Mold Pesticides Radon Science ... or www.earth911.com . Think before disposing of extra pesticides and containers: Never reuse empty pesticide containers. ...

  4. Disposal of Iodine-129

    International Nuclear Information System (INIS)

    Morgan, M.T.; Moore, J.G.; Devaney, H.E.; Rogers, G.C.; Williams, C.; Newman, E.

    1978-01-01

    One of the problems to be solved in the nuclear waste management field is the disposal of radioactive iodine-129, which is one of the more volatile and long-lived fission products. Studies have shown that fission products can be fixed in concrete for permanent disposal. Current studies have demonstrated that practical cementitious grouts may contain up to 18% iodine as barium iodate. The waste disposal criterion is based on the fact that harmful effects to present or future generations can be avoided by isolation and/or dilution. Long-term isolation is effective in deep, dry repositories; however, since penetration by water is possible, although unlikely, release was calculated based on leach rates into water. Further considerations have indicated that sea disposal on or in the ocean floor may be a more acceptable alternative

  5. Nuclear fuel waste disposal

    International Nuclear Information System (INIS)

    Allan, C.J.

    1993-01-01

    The Canadian concept for nuclear fuel waste disposal is based on disposing of the waste in a vault excavated 500-1000 m deep in intrusive igneous rock of the Canadian Shield. The author believes that, if the concept is accepted following review by a federal environmental assessment panel (probably in 1995), then it is important that implementation should begin without delay. His reasons are listed under the following headings: Environmental leadership and reducing the burden on future generations; Fostering public confidence in nuclear energy; Forestalling inaction by default; Preserving the knowledge base. Although disposal of reprocessing waste is a possible future alternative option, it will still almost certainly include a requirement for geologic disposal

  6. Integrated Disposal Facility

    Data.gov (United States)

    Federal Laboratory Consortium — Located near the center of the 586-square-mile Hanford Site is the Integrated Disposal Facility, also known as the IDF.This facility is a landfill similar in concept...

  7. Sutureless implantation of the perceval s aortic valve prosthesis through right anterior minithoracotomy.

    Science.gov (United States)

    Gilmanov, Daniyar; Miceli, Antonio; Bevilacqua, Stefano; Farneti, Pierandrea; Solinas, Marco; Ferrarini, Matteo; Glauber, Mattia

    2013-12-01

    Many new, less invasive strategies are proposed for aortic valve operation in elderly patients. Rapid deployment sutureless aortic valve prosthesis has been recently introduced. We analyzed our experience with a sutureless valve implanted through a minimally invasive approach. A retrospective observational study with prospectively registered data was conducted on 137 patients undergoing aortic valve replacement through a right anterior minithoracotomy. Between April 2011 and January 2013, 137 consecutive patients underwent aortic valve replacement with a recently introduced, rapid deployment, sutureless pericardial valve in minithoracotomy access (47 men; mean age, 76.6 ± 7.1 years). There were 35 obese patients with a body mass index of more than 30 kg/m(2). Mean logistic EuroSCORE I was 10.0; 74 (54%) patients were in New York Heart Association functional class III and IV. In all, 19 (13.9%), 45 (32.8%), and 73 (53.3%) patients received 21-, 23-, and 25-mm valve prostheses, respectively. The mean aortic cross-clamp and cardiopulmonary bypass times were 59.3 ± 19 min and 92.3 ± 27 min, respectively. No operative mortality occurred. Median stay in the intensive care unit was 1 day, with assisted ventilation necessary for a median of 6 hours. Three cases of postoperative ischemic stroke were observed (1 patient with a previous history of an ischemic cerebral event). Median hospital length of stay was 6 days. A sutureless valve for minimally invasive aortic valve replacement is a feasible, effective, and safe tool. Ultimately amplifying indications for less invasive aortic valve replacement in a high surgical risk subset of patients, it can become a valid alternative for transcatheter aortic valve implantation. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  8. Shallow land disposal technology

    Energy Technology Data Exchange (ETDEWEB)

    Pillette-Cousin, L. [Nuclear Environment Technology Insitute, Taejon (Korea, Republic of Korea )

    1997-12-31

    This paper covers the radioactive waste management policy and regulatory framework, the characteristics of low and intermediate level radioactive waste, the characteristics of waste package, the waste acceptance criteria, the waste acceptance and related activities, the design of the disposal system, the organization of waste transportation, the operation feature, the safety assessment of the Centre de L`Aube, the post closure measures, the closure of the Centre de la Mache disposal facility, the licensing issues. 3 tabs., 7 figs.

  9. Shallow land disposal technology

    International Nuclear Information System (INIS)

    Pillette-Cousin, L.

    1997-01-01

    This paper covers the radioactive waste management policy and regulatory framework, the characteristics of low and intermediate level radioactive waste, the characteristics of waste package, the waste acceptance criteria, the waste acceptance and related activities, the design of the disposal system, the organization of waste transportation, the operation feature, the safety assessment of the Centre de L'Aube, the post closure measures, the closure of the Centre de la Mache disposal facility, the licensing issues. 3 tabs., 7 figs

  10. Options for Heart Valve Replacement

    Science.gov (United States)

    ... Guide: Understanding Your Heart Valve Problem | Spanish Symptom Tracker | Spanish Pre-surgery Checklist | Spanish What Is Heart ... Cardiac Arrest: How Are They Different? 7 Warning Signs of a Heart Attack 8 Low Blood Pressure - ...

  11. Efficiency of aortic valve commissurotomy for congenital aortic valve stenosis in pediatric population

    Directory of Open Access Journals (Sweden)

    А. А. Лукьянов

    2015-10-01

    Full Text Available Background. This study was designed to evaluate short-term and long-term outcomes after open aortic valve commissurotomy in the pediatric patients at our center over a period of 10 years. Methods. A retrospective study of 94 patients who underwent open surgical commissurotomy because of aortic valve stenosis between 2003 and 2013 is presented. Follow-up time was in the range of 1 to 7 years. Results. The open aortic valve commissurotomy combined with debridement of leaflet free edge 36.1 %, LVOT myectomy 11.7%, leaflet suture plastic 7.4%, modified Konno procedure 6.3%, Brom's aortoplasty 4.2% was performed for all patients. Average cardiopulmonary bypass time was 59.2 30.7 min. Median aortic cross-clamping time was 31.52 15.1 min. Hospital complications were observed in 38.2% of cases. ICU time was in the range of 1 to 31 (mean 3.2 5.1 day. Artificial lung ventilation time varied from 2 to 76 (mean 15.3 18.3 hours. Inotropic support was needed in 26.5% of cases. Mean hospital stay time was 17.1 7.3 days. At follow-up between 2 and 7 years, reoperations were required for 3 patients who underwent a Ross procedure. Conclusions. The results evidence that open surgical commissurotomy is an effective way of treatment for aortic valve stenosis, considering the accuracy of plasty and additional techniques of leaflet correction. The best children age group for this type of operation is from first to five years of life.

  12. A nuclear radiation actuated valve for a nuclear reactor

    International Nuclear Information System (INIS)

    Christiansen, D.W.; Schively, D.P.

    1983-01-01

    The valve has a first part (such as a valve rod with piston) and a second part (such as a valve tube surrounding the valve rod, with the valve tube having side slots surrounding the piston). Both valve parts have known nuclear radiation swelling characteristics which are different. The valve parts are positioned so that the valve's first and second parts create a valve orifice which changes in size due to the different nuclear radiation caused swelling of the valve's first part compared to the valve's second part. The valve may be used in a nuclear reactor's core coolant system. (author)

  13. Thrombocytopenia following implantation of the stentless biological sorin freedom SOLO valve.

    Science.gov (United States)

    Gersak, Borut; Gartner, Urska; Antonic, Miha

    2011-07-01

    Stentless biological valves have proven advantages in hemodynamic performance and left ventricular function compared to stented biological valves. Following a marked postoperative fall in the platelet count of patients after implantation of the Freedom SOLO valve, the study aim was to confirm clinical observations that this effect was more severe in patients receiving Freedom SOLO valves than in those receiving St. Jude Medical (SJM) mechanical aortic valves. Preoperative and postoperative platelet counts were compared in two groups of patients who underwent aortic valve replacement (AVR) without any concomitant procedures between January and December 2007. Patients received either a Freedom SOLO valve (n = 28) or a SJM mechanical valve (n = 41). Mean values of platelet counts were compared using three multiple linear regression models. Platelet counts were significantly lower in the Freedom SOLO group than in the SJM group from the first postoperative day (POD 1) up to POD 6 (p SOLO group the platelet count fell below 30x10(9)/l, while the lowest level in the SJM group was 75x10(9)/l. Based on multiple linear regression models, the type of valve implanted had a statistically significant influence on postoperative platelet counts on POD 1, POD 3, and POD 5 (p SOLO group.

  14. A Study of System Pressure Transients Generated by Isolation Valve Open/Closure in Orifice Manifold

    Energy Technology Data Exchange (ETDEWEB)

    Kim, M. [KEPCO, Daejeon (Korea, Republic of); Bae, S. W.; Kim, J. I.; Park, S. J. [KHNP, Abu Dhabi (United Arab Emirates)

    2016-05-15

    In this study, we explore the effects of pressure transients on peak and minimal pressures caused by the actuation of isolation valve and control valve reacting to the combined orifice operation of orifice manifold with motor-operated valve installed in the rear of the orifice. We then use the collected data to direct our effort towards cause analysis and propose improvements to efficiency and safety of operation. This formation is used to by domestic and foreign nuclear power plants as a mean to control flow rate, producing required flow rate jointly together by combination of the orifices. No significant impacts on the internals of manifold orifice due to peak pressure has been observed, although chance of cavitation at the outlet of control valve is significant. Considering the peak pressure, as well as minimum pressure occurs in low flow rate conditions, the pressure transient is more so affected by the characteristics (modified equal percentage) of control valve. Isolation valve of the orifice and control valve operate organically, therefore stroke time for valves need to be applied in order for both valves to cooperatively formulate an optimized operation.

  15. Hemodynamics in the Valsalva sinuses after transcatheter aortic valve implantation (TAVI).

    Science.gov (United States)

    Ducci, Andrea; Tzamtzis, Spyridon; Mullen, Michael J; Burriesci, Gaetano

    2013-09-01

    The study aim was to assess, in vitro, the hemodynamic modifications produced by transcatheter valves in the Valsalva sinuses, by mean of phase-resolved particle image velocimetry (PIV) measurements. Flow measurements were performed on a glass mock aortic root that included three polymeric valve leaflets, before and after the implantation of a Medtronic CoreValve device and of an Edwards SAPIEN valve. All experiments were carried out in a hydro-mechanical cardiovascular pulse duplicator system (Vivitro Superpump System SP3891) that reproduced physiologically equivalent pressures and flow rates conforming to the requirements of the standard ISO 5840:2005. The flow dynamics, before and after implantation of the two prosthetic devices, was characterized on the basis of phase-resolved velocity field and viscous shear rate measurements. Direct comparison indicated that both transcatheter valves determined a significant variation of flow during the early stages of valve opening and during valve closure. In general, the presence of the two valve implants significantly reduced the flow activity in the Valsalva sinuses, promoting regions of stagnation at their base. The reduction in flow in the Valsalva sinuses could be associated with the higher incidence of ischemic events reported after transcatheter heart valve implantation.

  16. First report on a human percutaneous transluminal implantation of a self-expanding valve prosthesis for interventional treatment of aortic valve stenosis.

    Science.gov (United States)

    Grube, Eberhard; Laborde, Jean C; Zickmann, Bernfried; Gerckens, Ulrich; Felderhoff, Thomas; Sauren, Barthel; Bootsveld, Andreas; Buellesfeld, Lutz; Iversen, Stein

    2005-12-01

    Percutaneous aortic valve replacement is a new technology for the treatment of patients with significant aortic valve stenosis. We present the first report on a human implantation of a self-expanding aortic valve prosthesis, which is composed of three bovine pericardial leaflets inserted within a self-expanding nitinol stent. The 73-year-old woman presented with severe symptomatic aortic valve stenosis (mean transvalvular gradient of 45 mmHg; valve area of 0.7 cm2). Surgical valve replacement had been declined for the patient because of comorbidities, including previous bypass surgery. A retrograde approach via the common iliac artery was used for valve deployment. The contralateral femoral vessels were used for a temporary extracorporal circulation, unloading the left ventricle during the actual stent expansion. Clinical, hemodynamic, and echocardiographic outcomes were assessed serially during the procedure. Clinical and echocardiographic follow-up at day 1, 2, and 14 post procedure was performed to evaluate the short-term outcome. The prosthesis was successfully deployed within the native aortic valve, with accurate and stable positioning and with no impairment of the coronary artery or vein graft blood flow. 2D and doppler echo immediately after device deployment showed a significant reduction in transaortic mean pressure gradient (from 45 to 8 mmHg) without evidence of aortic or mitral valve insufficiency. The clinical status has then significantly improved. These results remained unchanged up to the day 14 follow-up. This case report demonstrates a successful percutaneous implantation of a self-expanding aortic valve prosthesis with remarkable functional and clinical improvements in the acute and short-term outcome. Copyright (c) 2005 Wiley-Liss, Inc.

  17. Engineering, environmental and economic planning for tailings disposal

    International Nuclear Information System (INIS)

    Poellot, J.H.

    1982-01-01

    There are two principal points made in this paper. First, mining waste materials, or tailings, are geotechnical materials. Their behavior follows the principles of soil mechanics and is predictable by these principles. Second, proper disposal, meaning safe, environmentally sound and economical disposal, requires planning and recognizing waste disposal as part of the total mining system and process. In the development of these two principles, planning, design, and economic considerations of mine tailings are discussed

  18. Ministernotomy: A preliminary experience in heart valve surgery

    Directory of Open Access Journals (Sweden)

    Kovačević Pavle

    2011-01-01

    Full Text Available Background/Aim. The last decade of the 20th century brought up a significant development in the field of minimally invasive approaches to the valvular heart surgery. Potential benefits of this method are: good esthetic appearance, reduced pain, reduction of postoperative hemorrhage and incidence of surgical site infection, shorter postoperative intensive care units (ICU period and overall in-hospital period. Partial upper median sternotomy currently presents as a state-of-the art method for minimally invasive surgery of cardiac valves. The aim of this study was to report on initial experience in application of this surgical method in the surgery of mitral and aortic valves. Methods. The study was designed and conducted in a prospective manner and included all the patients who underwent minimally invasive cardiac valve surgery through the partial upper median sternotomy during the period November 2008 - August 2009. We analyzed the data on mean age of patients, mean extubation time, mean postoperative drainage, mean duration of hospital stay, as well as on occurance of postoperative complications (postoperative bleeding, surgical site infection and cerebrovascular insult. Results. During the observed period, in the Institute for Cardiovascular Diseases of Vojvodina, Clinic for Cardiovascular Surgery, 17 ministernotomies were performed, with 14 aortic valve replacements (82.35% and 3 mitral valve replacements (17.65%. Mean age of the patients was 60.78 ± 12.99 years (64.71% males, 35.29% females. Mean extubation time was 12.53 ± 8.87 hours with 23.5% of the patients extubated in less than 8 hours. Mean duration of hospital stay was 12.35 ± 10.17 days (in 29.4% of the patients less than 8 days. Mean postoperative drainage was 547.06 ± 335.2 mL. Postoperative complications included: bleeding (5.88% and cerebrovascular insult (5.88%. One patient (5.88% required conversion to full sternotomy. Conclusion. Partial upper median sternotomy represents

  19. [Ministernotomy: a preliminary experience in heart valve surgery].

    Science.gov (United States)

    Kovarević, Pavle; Mihajlović, Bogoljub; Velicki, Lazar; Redzek, Aleksandar; Ivanović, Vladimir; Komazec, Nikola

    2011-05-01

    The last decade of the 20th century brought up a significant development in the field of minimally invasive approaches to the valvular heart surgery. Potential benefits of this method are: good esthetic appearance, reduced pain, reduction of postoperative hemorrhage and incidence of surgical site infection, shorter postoperative intensive care units (ICU) period and overall in-hospital period. Partial upper median stemotomy currently presents as a state-of-the art method for minimally invasive surgery of cardiac valves. The aim of this study was to report on initial experience in application of this surgical method in the surgery of mitral and aortic valves. The study was designed and conducted in a prospective manner and included all the patients who underwent minimally invasive cardiac valve surgery through the partial upper median stemotomy during the period November 2008 - August 2009. We analyzed the data on mean age of patients, mean extubation time, mean postoperative drainage, mean duration of hospital stay, as well as on occurance of postoperative complications (postoperative bleeding, surgical site infection and cerebrovascular insult). During the observed period, in the Institute for Cardiovascular Diseases of Vojvodina, Clinic for Cardiovascular Surgery, 17 ministernotomies were performed, with 14 aortic valve replacements (82.35%) and 3 mitral valve replacements (17.65%). Mean age of the patients was 60.78 +/- 12.99 years (64.71% males, 35.29% females). Mean extubation time was 12.53 +/- 8.87 hours with 23.5% of the patients extubated in less than 8 hours. Mean duration of hospital stay was 12.35 +/- 10.17 days (in 29.4% of the patients less than 8 days). Mean postoperative drainage was 547.06 +/- 335.2 mL. Postoperative complications included: bleeding (5.88%) and cerebrovascular insult (5.88%). One patient (5.88%) required conversion to full stemotomy. Partial upper median sternotomy represents the optimal surgical method for the interventions on the

  20. Outcomes of Solo Smart valve in a single-center experience of 270 patients.

    Science.gov (United States)

    Liu, Hao; Khani-Hanjani, Abbas; Yang, Siyuan; Wang, Wei; Sidhu, Surita; Mullen, John; Modry, Dennis; Wang, Shaohua

    2018-04-03

    The Solo Smart pericardial aortic valve has been widely used in Europe as an option for aortic valve replacement (AVR). We are reporting early and midterm clinical outcomes of AVR with the Solo Smart valve in a single North America center. This is a retrospective study of 270 consecutive patients who had AVR at Mazankowski Alberta Heart Institute from February 2011 to March 2015. Follow-up and echocardiographic data were collected retrospectively from electronic and paper charts. Univariate and multivariate analysis were performed to evaluate the results. The mean age was 71.2±10.0 years, 67.4% were male, and 79.3% had combined procedures. Mean STS Score was 4.18±3.91. Early mortality was 3.7% for the entire group and 0% for isolated aortic valve replacement group. Mean cross-clamp time for isolated AVR and AVR with concomitant procedure was 70.8±12.7min and 117.0±45.0min, respectively. Permanent pacemaker implantation was necessary in 2.2% of patients. Echocardiography demonstrated a reduction in mean gradients from 40.8±17.4mmHg to 7.6±3.7 mmHg and peak gradient from 72.5 ± 48.8 mmHg to 15.5±7.5 mmHg. The 1-, 3-, and 5- year overall survival was 93.0%, 86.5% and 75.9%, respectively. At 5 years, freedom from valve-related death was 92.4%, freedom from structural valve deterioration and freedom from aortic valve reoperation were 96.4% and 98%, respectively. The Solo Smart valve is safe and has excellent hemodynamic performance. Aortic valve reoperation and rates of valve-related adverse events during midterm follow-up were low.

  1. Trabeculectomy With Mitomycin C or Ahmed Valve Implantation in Eyes With Uveitic Glaucoma.

    Science.gov (United States)

    Bettis, Daniel I; Morshedi, Richard G; Chaya, Craig; Goldsmith, Jason; Crandall, Alan; Zabriskie, Norm

    2015-01-01

    To report and compare the results of trabeculectomy with mitomycin C (MMC) and Ahmed valve implantation in the management of uveitic glaucoma. The records of 41 eyes of 29 patients who underwent trabeculectomy with MMC or Ahmed valve implantation for uveitic glaucoma were retrospectively reviewed. Seventeen eyes underwent trabeculectomy with MMC, and 24 eyes underwent Ahmed valve implantation. Outcomes included postoperative intraocular pressure (IOP), percent reduction from preoperative IOP, postoperative number of medications, time to failure, and complications. Mean follow-up was 21.2 months in the trabeculectomy group and 23.8 months in the valve group (P=0.06). Mean IOP was reduced from 29.2 to 18.4 mm Hg in the trabeculectomy group (31.3%), compared with a reduction from 33.4 to 15.5 mm Hg in the Ahmed valve group (42.7%, P=0.53). Postoperatively, 1.76 medications were used in the trabeculectomy group, compared with 1.83 medications in the Ahmed valve group (P=0.89). Cumulative success at 1 year was 66.7% in the trabeculectomy group, compared with 100% in the Ahmed valve group (P=0.02). Mean time to failure was 8.36 months with trabeculectomy, and 21.8 months with Ahmed valve (P=0.02). Complications in both groups were typically rare and self-limited, with recurrent inflammation being most common. Although both trabeculectomy with MMC and Ahmed valve implantation are reasonable surgical options in the management of uncontrolled uveitic glaucoma, Ahmed valve implantation was associated with higher cumulative success rate at 1 year and a longer mean time to failure.

  2. Small sodium valve design and operating experience

    International Nuclear Information System (INIS)

    Abramson, R.; Elie, X.; Vercasson, M.; Nedelec, J.

    1974-01-01

    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.)

  3. Design of the Modular Pneumatic Valve Terminal

    Directory of Open Access Journals (Sweden)

    Jakub E. TAKOSOGLU

    2015-11-01

    Full Text Available The paper presents design of the modular pneumatic valve terminal, which was made on the basis of the patent application No A1 402905 „A valve for controlling fluid power drives, specially for pneumatic actuators, and the control system for fluid power drives valves”. The authors describe a method of operation of the system with double-acting valve and 5/2 (five ways and two position valve. Functions of the valve, and an example of application of the valve terminal in the production process were presented. 3D solid models of all the components of the valve were made. The paper presents a complete 3D model of the valve in various configurations. Using CAD-embedded SOLIDWORKS Flow Simulation computational fluid dynamics CFD analysis was also carried out of compressed air flow in the ways of the valve elements

  4. 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.

  5. Long-Term Results of Mitral Valve Repair

    Directory of Open Access Journals (Sweden)

    Francisco Diniz Affonso da Costa

    Full Text Available Abstract Introduction: Current guidelines state that patients with severe mitral regurgitation should be treated in reference centers with a high reparability rate, low mortality rate, and durable results. Objective: To analyze our global experience with the treatment of organic mitral regurgitation from various etiologies operated in a single center. Methods: We evaluated all surgically treated patients with organic mitral regurgitation from 2004-2017. Patients were evaluated clinically and by echocardiography every year. We determined early and late survival rates, valve related events and freedom from recurrent mitral regurgitation and tricuspid regurgitation. Valve failure was defined as any mitral regurgitation ≥ moderate degree or the need for reoperation for any reason. Results: Out of 133 patients with organic mitral regurgitation, 125 (93.9% were submitted to valve repair. Mean age was 57±15 years and 52 patients were males. The most common etiologies were degenerative disease (73 patients and rheumatic disease (34 patients. Early mortality was 2.4% and late survival was 84.3% at 10 years, which are similar to the age- and gender-matched general population. Only two patients developed severe mitral regurgitation, and both were reoperated (95.6% at 10 years. Freedom from mitral valve failure was 84.5% at 10 years, with no difference between degenerative and rheumatic valves. Overall, late ≥ moderate tricuspid regurgitation was present in 34% of the patients, being more common in the rheumatic ones. The use of tricuspid annuloplasty abolished this complication. Conclusion: We have demonstrated that mitral regurgitation due to organic mitral valve disease from various etiologies can be surgically treated with a high repair rate, low early mortality and long-term survival that are comparable to the matched general population. Concomitant treatment of atrial fibrillation and tricuspid valve may be important adjuncts to optimize long

  6. Outcomes in nonagenarians after heart valve replacement operation.

    Science.gov (United States)

    Edwards, Maria-Benedicta; Taylor, Kenneth M

    2003-03-01

    Changes in the age profile of the United Kingdom population and improvements in preoperative and postoperative care have resulted in increasing numbers of very elderly patients undergoing heart valve replacement (HVR) operations. Although HVR operations in nonagenarians are relatively uncommon, the demand for cardiac operations in this age group may increase over time. Outcomes after HVR operations in nonagenarians have not been well described yet. Therefore, the aim of this study was to determine outcomes in terms of early mortality and long-term survival in 35 nonagenarians after HVR operation. Data from the United Kingdom Heart Valve Registry were analyzed and nonagenarian patients were identified. Additional analyzed data include gender, valve position, valve type, valve size, operative priority, follow-up time, and date and cause of death. Kaplan-Meier actuarial curves were calculated to determine accurate 30-day mortality and long-term survival. On average five HVR operations are performed annually in the United Kingdom in nonagenarians with equal numbers of males and females. Aortic valve replacement with a bioprosthetic valve was the most common operation and 86% were elective admissions. Fourteen patients died within the review period; mean time to death was 402 days. Overall 30-day mortality was 17%, which was higher for males compared with females; females also displayed better long-term survival. HVR operations in nonagenarians carry a significantly higher risk of early mortality and reduced long-term survival. Despite increases in the age profile of the population, elective HVR operation with patients aged 90 years or older is likely to remain an infrequent surgical procedure reserved for very carefully selected patients.

  7. Fire analyses in central and disposal tunnels by APROS

    International Nuclear Information System (INIS)

    Peltokorpi, L.; Kukkola, T.; Nieminen, J.

    2012-12-01

    The central tunnels and the disposal tunnels on the north-east disposal area are the target areas of the fire studies. Target is to maintain under pressure in the fire zone in case of a fire. In the central tunnels a fire of a drilling jumbo with moderate fire propagation is used as heat release rate. In the disposal tunnel the heat release rate of a canister transfer and installation vehicle fire received as a result of the pyrolysis analyze as well as an average heat release rate of a van fire are used. Inlet air is to be conducted to the back end of the fire zone and the exhaust is to be lead out from the beginning of the fire zone. The worst location of the fire is in the beginning of the fire zone just below of the exhaust air clap valve. The size of the fire zone does not have big impact on pressure. In all analyzed cases the fire zone remains too long time over pressurized. Inlet air flow of a 30 m 3 /s is too much. The rotation controlled booster blowers will solve the pressure problems of the fire zone in fire cases. The rotation is controlled by the fire zone pressure. The fire of the canister transfer and installation vehicle in the central tunnel will not cause problems. The disposal tunnel fire door should be kept open, if the canister transfer and installation vehicle or the bentonite blocks transfer and installation vehicle is driven into the disposal tunnel. If a fire is caught in the disposal tunnel then the fire zone in the central tunnel is to be closed and the pressure is controlled by the rotation controlled booster blowers. If a personnel car or a van is driven into the disposal tunnel, then fire door of the disposal is to be kept closed against fires in the central tunnel. (orig.)

  8. Soft valves in plants

    Science.gov (United States)

    Park, Keunhwan; Tixier, Aude; Christensen, Anneline; Arnbjerg-Nielsen, Sif; Zwieniecki, Maciej; Jensen, Kaare

    2017-11-01

    Water and minerals flow from plant roots to leaves in the xylem, an interconnected network of vascular conduits that spans the full length of the organism. When a plant is subjected to drought stress, air pockets can spread inside the xylem, threatening the survival of the plant. Many plants prevent propagation of air by using hydrophobic nano-membranes in the ``pit'' pores that link adjacent xylem cells. This adds considerable resistance to flow. Interestingly, torus-margo pit pores in conifers are open and offer less resistance. To prevent propagation of air, conifers use a soft gating mechanism, which relies on hydrodynamic interactions between the xylem liquid and the elastic pit. However, it is unknown exactly how it is able to combine the seemingly antagonist functions of high permeability and resistance to propagation of air. We conduct experiments on biomimetic pores to elucidate the flow regulation mechanism. The design of plant valves is compared to other natural systems and optimal strategies are discussed. This work was supported by a research Grant (13166) from VILLUM FONDEN.

  9. Design and efficacy of a single-use bioreactor for heart valve tissue engineering.

    Science.gov (United States)

    Converse, Gabriel L; Buse, Eric E; Neill, Kari R; McFall, Christopher R; Lewis, Holley N; VeDepo, Mitchell C; Quinn, Rachael W; Hopkins, Richard A

    2017-02-01

    Heart valve tissue engineering offers the promise of improved treatments for congenital heart disorders; however, widespread clinical availability of a tissue engineered heart valve (TEHV) has been hindered by scientific and regulatory concerns, including the lack of a disposable, bioreactor system for nondestructive valve seeding and mechanical conditioning. Here we report the design for manufacture and the production of full scale, functional prototypes of such a system. To evaluate the efficacy of this bioreactor as a tool for seeding, ovine aortic valves were decellularized and subjected to seeding with human mesenchymal stem cells (hMSC). The effects of pulsatile conditioning using cyclic waveforms tuned to various negative and positive chamber pressures were evaluated, with respect to the seeding of cells on the decellularized leaflet and the infiltration of seeded cells into the interstitium of the leaflet. Infiltration of hMSCs into the aortic valve leaflet was observed following 72 h of conditioning under negative chamber pressure. Additional conditioning under positive pressure improved cellular infiltration, while retaining gene expression within the MSC-valve interstitial cell phenotype lineage. This protocol resulted in a subsurface pilot population of cells, not full tissue recellularization. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 249-259, 2017. © 2015 Wiley Periodicals, Inc.

  10. Aortic valve replacement with the Biocor PSB stentless xenograft.

    Science.gov (United States)

    Bertolini, P; Luciani, G B; Vecchi, B; Pugliese, P; Mazzucco, A

    1998-08-01

    The midterm clinical results after aortic valve replacement with the Biocor PSB stentless xenograft on all patients operated between October 1992 and October 1996 were reviewed. One hundred six patients, aged 70+/-6 years, had aortic valve replacement for aortic stenosis (67%), regurgitation (11%), or both (22%). Associated procedures were done in 49 patients (46%), including coronary artery bypass in 30 patients, mitral valve repair/replacement in 16, and ascending aorta replacement in 5 patients. Aortic cross-clamp and cardiopulmonary bypass times were 96+/-24 and 129+/-31 minutes, respectively. There were 3 (3%) early deaths due to low output (2 patients) and cerebrovascular accident (1 patient). Follow-up of survivors ranged from 6 to 66 months (mean, 39+/-14 months). Survival was 94%+/-2% and 90%+/-3% at 1 and 5 years. There were 5 late deaths due to cardiac cause (2), cancer (2), and pulmonary embolism (1 patient). No patient had structural valve deterioration, whereas 100% and 95%+/-3% were free from valve-related events at 1 and 5 years. There were two reoperations due to narrowing of the left coronary ostium and endocarditis, with an actuarial freedom from reoperation of 99%+/-1% and 98+/-1% at 1 and 5 years, respectively. Functional results demonstrated a mean peak transprosthetic gradient of 16+/-12 mm Hg, with only 1 patient (1%) with a 55 mm Hg gradient. No cases of valve regurgitation greater than mild were recorded at follow-up. Assessment of New York Heart Association functional class demonstrated a significant improvement (2.9+/-0.6 versus 1.4+/-0.7; p=0.01). All patients were free from anticoagulation. Aortic valve replacement using the Biocor PSB stentless xenograft offers excellent midterm survival, negligible valve deterioration, and a very low rate of valve-related events, which are comparable to estimates reported with other models of stentless xenografts and currently available stented xenografts. Hemodynamic performance is favorable and

  11. Surgical outcomes in native valve infectious endocarditis: the experience of the Cardiovascular Surgery Department - Cluj-Napoca Heart Institute.

    Science.gov (United States)

    Molnar, Adrian; Muresan, Ioan; Trifan, Catalin; Pop, Dana; Sacui, Diana

    2015-01-01

    The introduction of Duke's criteria and the improvement of imaging methods has lead to an earlier and a more accurate diagnosis of infectious endocarditis (IE). The options for the best therapeutic approach and the timing of surgery are still a matter of debate and require a close colaboration between the cardiologist, the infectionist and the cardiac surgeon. We undertook a retrospective, descriptive study, spanning over a period of five years (from January 1st, 2007 to December 31st, 2012), on 100 patients who underwent surgery for native valve infectious endocarditis in our unit. The patients' age varied between 13 and 77 years (with a mean of 54 years), of which 85 were males (85%). The main microorganisms responsible for IE were: Streptococcus Spp. (21 cases - 21%), Staphylococcus Spp. (15 cases - 15%), and Enterococcus Spp. (9 cases - 9%). The potential source of infection was identified in 26 patients (26%), with most cases being in the dental area (16 cases - 16%). The lesions caused by IE were situated in the left heart in 96 patients (96%), mostly on the aortic valve (50 cases - 50%). In most cases (82%) we found preexisting endocardial lesions which predisposed to the development of IE, most of them being degenerative valvular lesions (38 cases - 38%). We performed the following surgical procedures: surgery on a single valve - aortic valve replacement (40 cases), mitral valve replacement (19 cases), mitral valve repair (1 case), surgery on more than one valve - mitral and aortic valve replacement (20 cases), aortic and tricuspid valve replacement (1 case), aortic valve replacement with a mechanical valve associated with mitral valve repair (5 cases), aortic valve replacement with a biological valve associated with mitral valve repair (2 cases), and mitral valve replacement with a mechanical valve combined with De Vega procedure on the tricuspid valve (1 case). In 5 patients (5%) the bacteriological examination of valve pieces excised during surgery was

  12. Surgical outcomes in native valve infectious endocarditis: the experience of the Cardiovascular Surgery Department – Cluj-Napoca Heart Institute

    Science.gov (United States)

    MOLNAR, ADRIAN; MURESAN, IOAN; TRIFAN, CATALIN; POP, DANA; SACUI, DIANA

    2015-01-01

    Background and aims The introduction of Duke’s criteria and the improvement of imaging methods has lead to an earlier and a more accurate diagnosis of infectious endocarditis (IE). The options for the best therapeutic approach and the timing of surgery are still a matter of debate and require a close colaboration between the cardiologist, the infectionist and the cardiac surgeon. Methods We undertook a retrospective, descriptive study, spanning over a period of five years (from January 1st, 2007 to December 31st, 2012), on 100 patients who underwent surgery for native valve infectious endocarditis in our unit. Results The patients’ age varied between 13 and 77 years (with a mean of 54 years), of which 85 were males (85%). The main microorganisms responsible for IE were: Streptococcus Spp. (21 cases – 21%), Staphylococcus Spp. (15 cases – 15%), and Enterococcus Spp. (9 cases – 9%). The potential source of infection was identified in 26 patients (26%), with most cases being in the dental area (16 cases – 16%). The lesions caused by IE were situated in the left heart in 96 patients (96%), mostly on the aortic valve (50 cases – 50%). In most cases (82%) we found preexisting endocardial lesions which predisposed to the development of IE, most of them being degenerative valvular lesions (38 cases – 38%). We performed the following surgical procedures: surgery on a single valve - aortic valve replacement (40 cases), mitral valve replacement (19 cases), mitral valve repair (1 case), surgery on more than one valve – mitral and aortic valve replacement (20 cases), aortic and tricuspid valve replacement (1 case), aortic valve replacement with a mechanical valve associated with mitral valve repair (5 cases), aortic valve replacement with a biological valve associated with mitral valve repair (2 cases), and mitral valve replacement with a mechanical valve combined with De Vega procedure on the tricuspid valve (1 case). In 5 patients (5%) the bacteriological

  13. Left ventricular mass regression after porcine versus bovine aortic valve replacement: a randomized comparison.

    Science.gov (United States)

    Suri, Rakesh M; Zehr, Kenton J; Sundt, Thoralf M; Dearani, Joseph A; Daly, Richard C; Oh, Jae K; Schaff, Hartzell V

    2009-10-01

    It is unclear whether small differences in transprosthetic gradient between porcine and bovine biologic aortic valves translate into improved regression of left ventricular (LV) hypertrophy after aortic valve replacement. We investigated transprosthetic gradient, aortic valve orifice area, and LV mass in patients randomized to aortic valve replacement with either the Medtronic Mosaic (MM) porcine or an Edwards Perimount (EP) bovine pericardial bioprosthesis. One hundred fifty-two patients with aortic valve disease were randomly assigned to receive either the MM (n = 76) or an EP prosthesis. There were 89 men (59%), and the mean age was 76 years. Echocardiograms from preoperative, postoperative, predismissal, and 1-year time points were analyzed. Baseline characteristics and preoperative echocardiograms were similar between the two groups. The median implant size was 23 mm for both. There were no early deaths, and 10 patients (7%) died after dismissal. One hundred seven of 137 patients (78%) had a 1-year echocardiogram, and none required aortic valve reoperation. The mean aortic valve gradient at dismissal was 19.4 mm Hg (MM) versus13.5 mm Hg (EP; p regression of LV mass index (MM, -32.4 g/m(2) versus EP, -27.0 g/m(2); p = 0.40). Greater preoperative LV mass index was the sole independent predictor of greater LV mass regression after surgery (p regression of LV mass during the first year after aortic valve replacement.

  14. Late presentation of posterior urethral valve: two case reports

    Directory of Open Access Journals (Sweden)

    Carlos Márcio Nóbrega de Jesus

    Full Text Available CONTEXT: Posterior urethral valve (PUV is a widely known condition affecting males that generally presents prenatally or at birth. PUVs have also been occasionally described in literature in cases diagnosed during adolescence or adulthood. CASE REPORT: This report presents two late PUV cases, one in a teenager and the other in an adult. Both cases had had clinical signs of urinary tract infection and obstructive urinary symptoms. The diagnoses were made by means of voiding cystourethrography and urethrocystoscopy. Endoscopic valve fulguration was the treatment chosen for both. Their follow-up was uneventful.

  15. Transapical aortic valve implantation without angiography: proof of concept.

    Science.gov (United States)

    Ferrari, Enrico; Sulzer, Christopher; Marcucci, Carlo; Rizzo, Elena; Tozzi, Piergiorgio; von Segesser, Ludwig K

    2010-06-01

    Cardiac computed tomographic scans, coronary angiograms, and aortographies are routinely performed in transcatheter heart valve therapies. Consequently, all patients are exposed to multiple contrast injections with a following risk of nephrotoxicity and postoperative renal failure. The transapical aortic valve implantation without angiography can prevent contrast-related complications. Between November 2008 and November 2009, 30 consecutive high-risk patients (16 female, 53.3%) underwent transapical aortic valve implantation without angiography. The landmarks identification, the stent-valve positioning, and the postoperative control were routinely performed under transesophageal echocardiogram and fluoroscopic visualization without contrast injections. Mean age was 80.1 +/- 8.7 years. Mean valve gradient, aortic orifice area, and ejection fraction were 60.3 +/- 20.9 mm Hg, 0.7 +/- 0.16 cm(2), and 0.526 +/- 0.128, respectively. Risk factors were pulmonary hypertension (60%), peripheral vascular disease (70%), chronic pulmonary disease (50%), previous cardiac surgery (13.3%), and chronic renal insufficiency (40%) (mean blood creatinine and urea levels: 96.8 +/- 54 microg/dL and 8.45 +/- 5.15 mmol/L). Average European System for Cardiac Operative Risk Evaluation was 32.2 +/- 13.3%. Valve deployment in the ideal landing zone was 96.7% successful and valve embolization occurred once. Thirty-day mortality was 10% (3 patients). Causes of death were the following: intraoperative ventricular rupture (conversion to sternotomy), right ventricular failure, and bilateral pneumonia. Stroke occurred in one patient at postoperative day 9. Renal failure (postoperative mean blood creatinine and urea levels: 91.1 +/- 66.8 microg/dL and 7.27 +/- 3.45 mmol/L), myocardial infarction, and atrioventricular block were not detected. Transapical aortic valve implantation without angiography requires a short learning curve and can be performed routinely by experienced teams. Our report

  16. LOFT pressurizer safety: relief valve reliability

    International Nuclear Information System (INIS)

    Brown, E.S.

    1978-01-01

    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

  17. 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.

  18. Echocardiographic Evaluation of Hemodynamic Changes in Left-Sided Heart Valves in Pregnant Women With Valvular Heart Disease.

    Science.gov (United States)

    Samiei, Niloufar; Amirsardari, Mandana; Rezaei, Yousef; Parsaee, Mozhgan; Kashfi, Fahimeh; Hantoosh Zadeh, Sedigheh; Beikmohamadi, Somayeh; Fouladi, Masoumeh; Hosseini, Saeid; Peighambari, Mohammad Mehdi; Mohebbi, Ahmad

    2016-10-01

    Physiologic changes during pregnancy can deteriorate or improve patients' hemodynamic status in the setting of valvular heart disease. There are sparse data regarding the effect of pregnancy on valve hemodynamics in normal pregnant women with known valvular heart disease. In a prospective study from July 2014 to January 2016, a total of 52 normal pregnant women who had mitral stenosis, aortic stenosis, or a history of mitral valve or aortic valve replacements were assessed. All patients underwent echocardiographic examinations and hemodynamic parameters were measured for both the mitral valve and aortic valve at first, second, and third trimesters. The parameters included mean gradient, peak gradient, mean gradient/heart rate, peak gradient/heart rate, pressure halftime, dimensionless velocity index, and valve area. Although most hemodynamic parameters (i.e., mean gradient, peak gradient, mean gradient/heart rate, and peak gradient/heart rate) increased approximately 50% from first to second trimester and first to third trimester (p 0.05). The ratio of changes between trimesters for valve area and dimensionless velocity index were comparable. No clinical decompensations were observed except for 3 and 7 cases of deterioration to functional class II at second and third trimesters, respectively. In conclusion, during a full-term and uncomplicated pregnancy, mitral and aortic valve gradients increase without significant changes in valve area that are more marked between the second and first trimester than between the third and second trimester. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Anatomic characteristics of bileaflet mitral valve prolapse--Barlow disease--in patients undergoing mitral valve repair.

    Science.gov (United States)

    Rostagno, Carlo; Droandi, Ginevra; Rossi, Alessandra; Bevilacqua, Sergio; Romagnoli, Stefano; Montesi, Gian Franco; Stefàno, Pier Luigi

    2014-01-01

    Barlow disease is a still challenging pathology for the surgeon. Aim of the present study is to report anatomic abnormalities of mitral valve in patients undergoing mitral valve repair. Between January 1st, 2007, and December 31st, 2010, 85 consecutive patients (54 men and 31 women, mean age 59 +/- 14 years--range: 28-85 years) with the features of a Barlow mitral valve disease underwent mitral repair Forty seven percent of patients were in New York Heart Association functional class III or IV. Preoperative transesophageal echocardiography was compared with anatomical findings at the moment of surgery. Transthoracic echocardiography diagnosis of Barlow disease according to the criteria described by Carpentier was confirmed at anatomical inspection. Annular calcifications were found in 28 patients while 7 patients presented single or multiple clefts. A flail posterior mitral leaflet was detected in 32 subjects, while a flail anterior leaflet in 8. Elongation of chordae tendineae was demonstrated in 45 patients and chordal rupture in 31. All patients showed at trans esophageal echocardiography the typical features of Barlow disease. Seventy-seven (90.6%) patients had severe mitral valve regurgitation, in the remaining 9.4% it was moderate to severe. Transesophageal echocardiography failed to identify clefts in 2/7 and chordal rupture in 4/31. bileaflet prolapse > 2 mm, billowing valve with excess tissue and thickened leaflets > or = 3 mm, and severe annular dilatation, are characteristics of Barlow disease, however the identification of the associated and complex abnormalities of mitral valve is necessary to obtain optimal valve repair.

  20. [Aortic valve preservation in Marfan syndrome. Initial experience].

    Science.gov (United States)

    Forteza, Alberto; Cortina, Jose M; Sánchez, Violeta; Centeno, Jorge; López, M Jesús; Pérez de la Sota, Enrique; Rufilanchas, Juan J

    2007-05-01

    Preservation of the aortic valve using the technique described by David has been shown to be as effective as the Bentall-De Bono procedure. It avoids both the need for long-term anticoagulation and the complications associated with mechanical prostheses. We report our initial experience using this technique in patients with Marfan syndrome. Between April 2004 and April 2006, we used the David reimplantation technique in 40 patients with an aortic root aneurysm. Eighteen patients had Marfan syndrome. Their median age was 29 years (13-55 years). Echocardiography showed that the median diameter of the aortic sinus was 53 mm (46-59 mm). In 17 patients, aortic valve preservation was possible. No patient died during hospitalization and there were no significant complications. On echocardiography at discharge, no patient had greater than grade-II aortic regurgitation. During a median follow-up period of 8 months (1-24 months), one patient died due to rupture of an abdominal aneurysm. The others are all in New York Heart Association class I. Preservation of the aortic valve by means of valve reimplantation produced excellent results. It avoided both the thromboembolic and hemorrhagic complications associated with prostheses and the need for long-term anticoagulation. If reimplanted valves continue to function adequately over the long term, this technique should become the treatment of choice for aneurysms of the ascending aorta in patients with Marfan syndrome.

  1. Pump having pistons and valves made of electroactive actuators

    Science.gov (United States)

    Bar-Cohen, Yoseph (Inventor)

    1997-01-01

    The present invention provides a pump for inducing a displacement of a fluid from a first medium to a second medium, including a conduit coupled to the first and second media, a transducing material piston defining a pump chamber in the conduit and being transversely displaceable for increasing a volume of the chamber to extract the fluid from the first medium to the chamber and for decreasing the chamber volume to force the fluid from the chamber to the second medium, a first transducing material valve mounted in the conduit between the piston and the first medium and being transversely displaceable from a closed position to an open position to admit the fluid to the chamber, and control means for changing a first field applied to the piston to displace the piston for changing the chamber volume and for changing a second field applied to the first valve to change the position of the first valve.

  2. Reasons for conversion and adverse intraoperative events in Endoscopic Port Access™ atrioventricular valve surgery and minimally invasive aortic valve surgery.

    Science.gov (United States)

    van der Merwe, Johan; Van Praet, Frank; Stockman, Bernard; Degrieck, Ivan; Vermeulen, Yvette; Casselman, Filip

    2018-02-14

    This study reports the factors that contribute to sternotomy conversions (SCs) and adverse intraoperative events in minimally invasive aortic valve surgery (MI-AVS) and minimally invasive Endoscopic Port Access™ atrioventricular valve surgery (MI-PAS). In total, 3780 consecutive patients with either aortic valve disease or atrioventricular valve disease underwent minimally invasive valve surgery (MIVS) at our institution between 1 February 1997 and 31 March 2016. MI-AVS was performed in 908 patients (mean age 69.2 ± 11.3 years, 45.2% women, 6.2% redo cardiac surgery) and MI-PAS in 2872 patients (mean age 64.1 ± 13.3 years, 46.7% women, 12.2% redo cardiac surgery). A cumulative total of 4415 MIVS procedures (MI-AVS = 908, MI-PAS = 3507) included 1537 valve replacements (MI-AVS = 896, MI-PAS = 641) and 2878 isolated or combined valve repairs (MI-AVS = 12, MI-PAS = 2866). SC was required in 3.0% (n = 114 of 3780) of MIVS patients, which occurred in 3.1% (n = 28 of 908) of MI-AVS patients and 3.0% (n = 86 of 2872) of MI-PAS patients, respectively. Reasons for SC in MI-AVS included inadequate visualization (n = 4, 0.4%) and arterial cannulation difficulty (n = 7, 0.8%). For MI-PAS, SC was required in 54 (2.5%) isolated mitral valve procedures (n = 2183). Factors that contributed to SC in MI-PAS included lung adhesions (n = 35, 1.2%), inadequate visualization (n = 2, 0.1%), ventricular bleeding (n = 3, 0.1%) and atrioventricular dehiscence (n = 5, 0.2%). Neurological deficit occurred in 1 (0.1%) and 3 (3.5%) MI-AVS and MI-PAS conversions, respectively. No operative or 30-day mortalities were observed in MI-AVS conversions (n = 28). The 30-day mortality associated with SC in MI-PAS (n = 86) was 10.5% (n = 9). MIVS is increasingly being recognized as the 'gold-standard' for surgical valve interventions in the context of rapidly expanding catheter-based technology and increasing

  3. 12 CFR 222.83 - Disposal of consumer information.

    Science.gov (United States)

    2010-01-01

    ... RESERVE SYSTEM FAIR CREDIT REPORTING (REGULATION V) Duties of Users of Consumer Reports Regarding Identity Theft § 222.83 Disposal of consumer information. (a) Definitions as used in this section. (1) You means... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Disposal of consumer information. 222.83...

  4. Landfill disposal risk assessment

    International Nuclear Information System (INIS)

    Mininni, G.; Passino, R.; Spinosa, L.

    1993-01-01

    Landfill disposal is the most used waste disposal system in Italy, due to its low costs and also to the great opposition of populations towards new incineration plants and the adjustment of the existing ones. Nevertheless, landfills may present many environmental problems as far as leachate and biogas are concerned directly influencing water, air and soil. This paper shows the most important aspects to be considered for a correct evaluation of environmental impacts caused by a landfill of urban wastes. Moreover, detection systems for on site control of pollution phenomena are presented and some measures for an optimal operation of a landfill are suggested

  5. Disposal of hazardous wastes

    International Nuclear Information System (INIS)

    Barnhart, B.J.

    1978-01-01

    The Fifth Life Sciences Symposium entitled Hazardous Solid Wastes and Their Disposal on October 12 through 14, 1977 was summarized. The topic was the passage of the National Resources Conservation and Recovery Act of 1976 will force some type of action on all hazardous solid wastes. Some major points covered were: the formulation of a definition of a hazardous solid waste, assessment of long-term risk, list of specific materials or general criteria to specify the wastes of concern, Bioethics, sources of hazardous waste, industrial and agricultural wastes, coal wastes, radioactive wastes, and disposal of wastes

  6. Radioactive waste (disposal)

    International Nuclear Information System (INIS)

    Jenkin, P.

    1985-01-01

    The disposal of low- and intermediate-level radioactive wastes was discussed. The following aspects were covered: public consultation on the principles for assessing disposal facilities; procedures for dealing with the possible sites which the Nuclear Industry Radioactive Waste Executive (NIREX) had originally identified; geological investigations to be carried out by NIREX to search for alternative sites; announcement that proposal for a site at Billingham is not to proceed further; NIREX membership; storage of radioactive wastes; public inquiries; social and environmental aspects; safety aspects; interest groups; public relations; government policies. (U.K.)

  7. Disposal and reclamation of southwestern coal and uranium wastes

    International Nuclear Information System (INIS)

    Wewerka, E.M.

    1979-01-01

    The types of solid wastes and effluents produced by the southwestern coal and uranium mining and milling industries are considered, and the current methods for the disposal and reclamation of these materials discussed. The major means of disposing of the solid wastes from both industries is by land fill or in some instances ponding. Sludges or aqueous wastes are normally discharged into settling and evaporative ponds. Basic reclamation measures for nearly all coal and uranium waste disposal sites include solids stabilization, compacting, grading, soil preparation, and revegetation. Impermeable liners and caps are beginning to be applied to disposal sites for some of the more harmful coal and uranium waste materials

  8. Butterfly valve of all rubber lining type

    International Nuclear Information System (INIS)

    Shimada, Shosaku; Nakatsuma, Sumiya; Sasaki, Iwao; Aoki, Naoshi.

    1982-01-01

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

  9. Sequential transcatheter aortic valve implantation due to valve dislodgement - a Portico valve implanted over a CoreValve bioprosthesis.

    Science.gov (United States)

    Campante Teles, Rui; Costa, Cátia; Almeida, Manuel; Brito, João; Sondergaard, Lars; Neves, José P; Abecasis, João; M Gabriel, Henrique

    2017-03-01

    Transcatheter aortic valve implantation (TAVI) has become an important treatment in high surgical risk patients with severe aortic stenosis (AS), whose complications need to be managed promptly. The authors report the case of an 86-year-old woman presenting with severe symptomatic AS, rejected for surgery due to advanced age and comorbidities. The patient underwent a first TAVI, with implantation of a Medtronic CoreValve ® , which became dislodged and migrated to the ascending aorta. Due to the previous balloon valvuloplasty, the patient's AS became moderate, and her symptoms improved. After several months, she required another intervention, performed with a St. Jude Portico ® repositionable self-expanding transcatheter aortic valve. There was a good clinical response that was maintained at one-year follow-up. The use of a self-expanding transcatheter bioprosthesis with repositioning features is a solution in cases of valve dislocation to avoid suboptimal positioning of a second implant, especially when the two valves have to be positioned overlapping or partially overlapping each other. Copyright © 2017 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

  10. Cavitation noise from butterfly valves

    International Nuclear Information System (INIS)

    Rahmeyer, W.J.

    1982-01-01

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

  11. Anterior urethral valves: not such a benign condition…

    Directory of Open Access Journals (Sweden)

    Omar eCruz-Diaz

    2013-11-01

    Full Text Available Purpose: Anterior urethral valves (AUV is an unusual cause of congenital obstruction of the male urethra, being 15 to 30 times less common than posterior urethral valves (PUV. It has been suggested that patients with congenital anterior urethral obstruction have a better prognosis than those with PUV.The long term prognosis of anterior urethral valves is not clear in the literature. In this report we describe our experience and long-term follow up of patients with AUV.Materials and methods: We retrospectively identified 13 patients who presented with the diagnosis of AUV in our institutions between 1994 and 2012. From the 11 patients included, we evaluated the gestational age, ultrasound and voiding cystourethrogram findings, age upon valve ablation, micturition pattern, creatinine and clinical follow up.Results: Between 1994 and 2012 we evaluated 150 patients with the diagnosis of urethral valves, where 11 patients (7.3% had AUV and an adequate follow up. Mean follow up is 6.3 years. 5 patients (45.4% had pre-natal diagnosis of AUV. The most common prenatal ultrasonographic finding was bilateral hydronephrosis and distended bladder.The mean gestational age was 37.6 weeks. Postnatally, 90% had trabeculated bladder, 80% hydronephrosis and 40% renal dysplasia. The most common clinical presentation was urinary tract infection in 5 patients (45.4%.7 patients (63.6% had primary transurethral valve resection or laser ablation and 3 patients (27.2% had primary vesicostomies. One boy (9.1% had urethrostomy with urethral diverticulum excision. 2 patients (18.2% developed end-stage renal disease (ESRD.Conclusions: Early urinary tract obstruction resulted in ESRD in 18% of our patient population. In our series, the complication rate and the evolution to renal failure are high and similar to patients with PUV. In patients with AUV we recommend long-term follow up and close evaluation of patient’s bladder and renal function.

  12. Surgical treatment of aortic valve endocarditis: a 26-year experience

    Directory of Open Access Journals (Sweden)

    Taylan Adademir

    2014-03-01

    Full Text Available Objective: We have retrospectively analyzed the results of the operations made for aortic valve endocarditis in a single center in 26 years. Methods: From June 1985 to January 2011, 174 patients were operated for aortic valve endocarditis. One hundred and thirty-eight (79.3% patients were male and the mean age was 39.3±14.4 (9-77 years. Twenty-seven (15.5% patients had prosthetic valve endocarditis. The mean duration of follow-up was 7.3±4.2 years (0.1-18.2 adding up to a total of 1030.8 patient/years. Results: Two hundred and eighty-two procedures were performed. The most frequently performed procedure was aortic valve replacement with mechanical prosthesis (81.6%. In-hospital mortality occurred in 27 (15.5% cases. Postoperatively, 25 (14.4% patients had low cardiac output and 17 (9.8% heart block. The actuarial survival rates for 10 and 15 years were 74.6±3.7% and 61.1±10.3%, respectively. In-hospital mortality was found to be associated with female gender, emergency operation, postoperative renal failure and low cardiac output. The long term mortality was significantly associated with mitral valve involvement. Male gender was found to be a significant risk factor for recurrence in the follow-up. Conclusion: Surgery for aortic valve endocarditis has significant mortality. Emergency operation, female gender, postoperative renal failure and low cardiac output are significant risk factors. Risk for recurrence and need for reoperation is low.

  13. Structural valve deterioration in the Mitroflow biological heart valve prosthesis

    DEFF Research Database (Denmark)

    Issa, Issa Farah; Poulsen, Steen Hvitfeldt; Waziri, Farhad

    2018-01-01

    OBJECTIVES: Concern has been raised regarding the long-term durability of the Mitroflow biological heart valve prosthesis. Our aim was to assess the incidence of structural valve degeneration (SVD) for the Mitroflow bioprosthesis in a nationwide study in Denmark including all patients alive......: A total of 173 patients were diagnosed with SVD by echocardiography. Of these, 64 (11%) patients had severe SVD and 109 (19%) patients moderate SVD. Severe SVD was associated with the age of the prosthesis and small prosthesis size [Size 21: hazard ratio (95% confidence interval, CI) 2.72 (0.97-8.56), P...

  14. The JUPITER registry: 1-year results of transapical aortic valve implantation using a second-generation transcatheter heart valve in patients with aortic stenosis.

    Science.gov (United States)

    Silaschi, Miriam; Treede, Hendrik; Rastan, Ardawan J; Baumbach, Hardy; Beyersdorf, Friedhelm; Kappert, Utz; Eichinger, Walter; Rüter, Florian; de Kroon, Thomas L; Lange, Rüdiger; Ensminger, Stephan; Wendler, Olaf

    2016-11-01

    Transcatheter aortic valve replacement (TAVR) is an established therapy for patients with aortic stenosis (AS) at high surgical risk. The JenaValve™ is a second-generation, self-expanding transcatheter heart valve (THV), implanted through transapical access (TA). During stent deployment, a specific 'clipping-mechanism' engages native aortic valve cusps for fixation. We present 1-year outcomes of the JUPITER registry, a post-market registry of the JenaValve for TA-TAVR. The JUPITER registry is a prospective, multicentre, uncontrolled and observational European study to evaluate the long-term safety and effectiveness of the Conformité Européenne-marked JenaValve THV. A total of 180 patients with AS were enrolled between 2012 and 2014. End-points were adjudicated in accordance with the valve academic research consortium document no. 1 definitions. The mean age was 80.4 ± 5.9 years and the mean logistic European system for cardiac operative risk evaluation I 21.2 ± 14.7%. The procedure was successful in 95.0% (171/180), implantation of a second THV (valve-in-valve) was performed in 2.2% (4/180) and conversion to surgical aortic valve replacement (SAVR) was necessary in 2.8% (5/180). No annular rupture or coronary ostia obstruction occurred. Two patients required SAVR after the day of index procedure (1.1%). All-cause mortality at 30 days was 11.1% (20/180), being cardiovascular in 7.2% (13/180). A major stroke occurred in 1.1% (2/180) at 30 days, no additional major strokes were observed during 1 year. All-cause mortality after 30 days was 13.1% (21/160) and combined efficacy at 1 year was 80.8% (122/151). At 1-year follow-up, no patient presented with more than moderate paravalvular leakage, while 2 patients (3.2%) showed moderate, 12 (19.0%) mild and 49 (82.4%) trace/none paravalvular regurgitation. In a high-risk cohort of patients undergoing TA-TAVR for AS, the use of the JenaValve THV is safe and effective. In patients at higher risk for coronary ostia

  15. Complications and 2-year valve survival following Ahmed valve implantation during the first 2 years of life.

    Science.gov (United States)

    Almobarak, F; Al-Mobarak, F; Khan, A O

    2009-06-01

    To report complications and 2-year valve survival following Ahmed valve implantation during the first 2 years of life. Retrospective institutional case series. Forty-two eyes of 36 patients with Ahmed valve implantation (without prior drainage device surgery) during the first 2 years of life and 2 years' postsurgical follow-up were identified. Most eyes had primary congenital glaucoma (28/42, 66.7%), aphakic glaucoma (5/42, 11.9%) or Peters anomaly (5/42, 11.9%). All but three eyes had prior ocular surgery. Surgery was at a mean age of 11.83 months (m) (SD 5.63). The most common significant postoperative complications were tube malpositioning requiring intervention (11/42, 26.2%), endophthalmitis (3/42, 7.1%; one with tube exposure) and retinal detachment (3/42, 7.1%). Thirty-six eyes (85.8%) required resumption of antiglaucoma medications to maintain intraocular pressure (IOP) valve survival (IOPendophthalmitis and retinal detachment are known potential complications following any incisional surgery for advanced buphthalmos; however, tube exposure is a unique potential problem following aqueous shunt implantation that can lead to intraocular infection. Cumulative valve survival 2 years following implantation was 63.3%.

  16. Disposal of Radioactive Waste. Specific Safety Requirements (Spanish Edition)

    International Nuclear Information System (INIS)

    2012-01-01

    This Safety Requirements publication applies to the disposal of radioactive waste of all types by means of emplacement in designed disposal facilities, subject to the necessary limitations and controls being placed on the disposal of the waste and on the development, operation and closure of facilities. The classification of radioactive waste is discussed. This Safety Requirements publication establishes requirements to provide assurance of the radiation safety of the disposal of radioactive waste, in the operation of a disposal facility and especially after its closure. The fundamental safety objective is to protect people and the environment from harmful effects of ionizing radiation. This is achieved by setting requirements on the site selection and evaluation and design of a disposal facility, and on its construction, operation and closure, including organizational and regulatory requirements.

  17. Percutaneous implantation of the first repositionable aortic valve prosthesis in a patient with severe aortic stenosis.

    Science.gov (United States)

    Buellesfeld, Lutz; Gerckens, Ulrich; Grube, Eberhard

    2008-04-01

    Percutaneous aortic valve replacement is a new less-invasive alternative for high-risk surgical candidates with aortic stenosis. However, the clinical experience is still limited, and the currently available 'first-generation devices' revealed technical shortcomings, such as lack of repositionability and presence of paravalvular leakages. We report the first-in-man experience with the new self-expanding Lotus Valve prosthesis composed of a nitinol frame with implemented bovine pericardial leaflets which is designed to address these issues, being repositionable and covered by a flexible membrane to seal paravalvular gaps. We implanted this prosthesis in a 93-year old patient presenting with severe symptomatic aortic stenosis (valve area: 0.6 cm(2)). Surgical valve replacement had been declined due to comorbidities. We used a retrograde approach for insertion of the 21-French Lotus catheter loaded with the valve prosthesis via surgical cut-down to the external iliac artery. Positioning of the valve was guided by transesophageal echo and supra-aortic angiograms. The prosthesis was successfully inserted and deployed within the calcified native valve. Echocardiography immediately after device deployment showed a significant reduction of the transaortic mean pressure gradient (32 to 9 mmHg; final valve area 1.7 cm(2)) without evidence of residual aortic regurgitation. The postprocedural clinical status improved from NYHA-IV to NYHA-II. These results remained unchanged up to the 3 month follow-up. Successful percutaneous aortic valve replacement can be performed using the new self-expanding and repositionable Lotus valve for treatment of high-risk patients with aortic valve stenosis. Further studies are mandatory to assess device safety and efficacy in larger patient populations. Copyright 2008 Wiley-Liss, Inc.

  18. Performance and morphology of decellularized pulmonary valves implanted in juvenile sheep.

    Science.gov (United States)

    Quinn, Rachael W; Hilbert, Stephen L; Bert, Arthur A; Drake, Bill W; Bustamante, Julie A; Fenton, Jason E; Moriarty, Sara J; Neighbors, Stacy L; Lofland, Gary K; Hopkins, Richard A

    2011-07-01

    Because of cryopreserved heart valve-mediated immune responses, decellularized allograft valves are an attractive option in children and young adults. The objective of this study was to investigate the performance and morphologic features of decellularized pulmonary valves implanted in the right ventricular outflow tract of juvenile sheep. Right ventricular outflow tract reconstructions in juvenile sheep (160±9 days) using cryopreserved pulmonary allografts (n=6), porcine aortic root bioprostheses (n=4), or detergent/enzyme-decellularized pulmonary allografts (n=8) were performed. Valve performance (echocardiography) and morphologic features (gross, radiographic, and histologic examination) were evaluated 20 weeks after implantation. Decellularization reduced DNA in valve cusps by 99.3%. Bioprosthetic valves had the largest peak and mean gradients versus decellularized valves (p=0.03; p<0.001) and cryopreserved valves (p=0.01; p=0.001), which were similar (p=0.45; p=0.40). Regurgitation was minimal and similar for all groups (p=0.16). No cusp calcification was observed in any valve type. Arterial wall calcification was present in cryopreserved and bioprosthetic grafts but not in decellularized valves. No autologous recellularization or inflammation occurred in bioprostheses, whereas cellularity progressively decreased in cryopreserved grafts. Autologous recellularization was present in decellularized arterial walls and variably extending into the cusps. Cryopreserved and decellularized graft hemodynamic performance was comparable. Autologous recellularization of the decellularized pulmonary arterial wall was consistently observed, with variable cusp recellularization. As demonstrated in this study, decellularized allograft valves have the potential for autologous recellularization. Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  19. Novel self-expandable, stent-based transcatheter pulmonic valve: a preclinical animal study.

    Science.gov (United States)

    Kim, Gi Beom; Lim, Hong-Gook; Kim, Yong Jin; Choi, Eun Young; Kwon, Bo Sang; Jeong, Saeromi

    2014-04-15

    Because transcatheter implantation of pulmonary valve is indicated for limited-size dysfunctional right ventricular outflow tract only as a balloon-expandable stent, we investigated the feasibility of a large-diameter self-expandable valved stent and the durability of the valve after >6 months. We made a nitinol-wire-based, self-expandable valved stent with leaflets made from porcine pericardium. The porcine pericardium was treated with α-galactosidase, glutaraldehyde, and glycine after decellularization. After cutting the inguinal or cervical area, we implanted a valved stent in 12 sheep through the femoral or jugular vein by using an 18-Fr delivery catheter, controlling the catheter handles and hook block under fluoroscopic and echocardiographic guidance. The mean body weight of sheep was 43.9 kg. We successfully implanted valved stents (diameter: 24 mm in 7 sheep, 26 mm in 5 sheep) in good position in 8 sheep, in the main pulmonary artery (PA) in 2 sheep, and in the right ventricular outlet tract (RVOT) in 2 sheep. We sacrificed 8 sheep (6 sheep in good position, 1 sheep in the main PA, and 1 sheep in the RVOT) after >6 months. Five of the 6 sheep implanted in good position showed well-preserved valve morphology at the time of sacrifice. Histologic findings after routine sacrifice showed well-maintained collagen wave structure and no visible calcification in all explanted valve leaflets. Transcatheter implantation of a nitinol-wire-based, self-expandable valved stent in the pulmonic valve was feasible, and stents implanted in good position showed well-preserved valve leaflets with functional competence in the mid-term results. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  20. Remote maintenance of a combined regeneration-isolation valve for the ITER Torus vacuum pumping system

    International Nuclear Information System (INIS)

    Stringer, J.; Blevins, J.

    1992-01-01

    A large diameter valve suitable for high vacuum operation is under study for ITER Torus evacuation. The valves must comply with specifications for leak-tightness, radiation resistance, dust tolerance, overpressure, and thermal gradients. Remote maintenance of the seal and valve moving parts without disturbance to the rest of the valve system is a requirement. This paper describes tow methods of seal exchange by remote means. In the first method, a flask is proposed for the valve moving parts exchange in inert gas, when the machine is shut down. In the second method a novel concept is described for seal exchange while under vacuum, without having to bring the machine up to atmosphere. The advantages of this method are that scheduled remote handling (RH) operations and outages for seal replacement are not required. Also, the need for a flask is avoided

  1. Bicuspid Aortic Valve Disease: A Comprehensive Review

    OpenAIRE

    Mordi, Ify; Tzemos, Nikolaos

    2012-01-01

    Bicuspid aortic valve is the commonest congenital cardiac abnormality in the general population. This paper article will discuss our current knowledge of the anatomy, pathophysiology, genetics, and clinical aspects of bicuspid aortic valve disease.

  2. Echocardiographic evaluation of heart valve prosthetic dysfunction

    Directory of Open Access Journals (Sweden)

    Yuriy Ivaniv

    2018-02-01

    Full Text Available Patients with replaced heart valve submitted to echocardiographic examination may have symptoms related either to valvular malfunction or ventricular dysfunction from different causes. Clinical examination is not reliable in a prosthetic valve evaluation and the main information regarding its function could be obtained using different cardiac ultrasound modalities. This review provides a description of echocardiographic and Doppler techniques useful in evaluation of prosthetic heart valves. For the interpretation of echocardiography there is a need in special knowledge of prosthesis types and possible reasons of prosthetic function deterioration. Echocardiography allows to reveal valve thrombosis, pannus formation, vegetation and such complications of infective endocarditis as valve ring abscess or dehiscence. Transthoracic echocardiography requires different section plane angles and unconventional views. Transesophageal echocardiography is more often used than in native valve examination due to better visualization of prosthetic valve structure and function. Three-dimensional echocardiography could provide more detailed visual information especially in the assessment of paravalvular regurgitation or valve obstruction.

  3. Bistable fluidic valve is electrically switched

    Science.gov (United States)

    Fiet, O.; Salvinski, R. J.

    1970-01-01

    Bistable control valve is selectively switched by direct application of an electrical field to divert fluid from one output channel to another. Valve is inexpensive, has no moving parts, and operates on fluids which are relatively poor electrical conductors.

  4. Comparative study between CardiaMed valves (freely floating valve leaflets versus St. Jude Medical (fixed valve leaflets in mitral valve replacement surgery

    Directory of Open Access Journals (Sweden)

    Mostafa Ahmed

    2017-09-01

    Conclusions: CardiaMed freely floating leaflet prostheses showed good hemodynamic characteristics. The prosthesis adequately corrects hemodynamics and is safe and no worse than the St. Jude Medical valve in the mitral valve position.

  5. Prosthetic Mitral Valve Leaflet Escape

    Science.gov (United States)

    Kim, Darae; Hun, Sin Sang; Cho, In-Jeong; Shim, Chi-Young; Ha, Jong-Won; Chung, Namsik; Ju, Hyun Chul; Sohn, Jang Won

    2013-01-01

    Leaflet escape of prosthetic valve is rare but potentially life threatening. It is essential to make timely diagnosis in order to avoid mortality. Transesophageal echocardiography and cinefluoroscopy is usually diagnostic and the location of the missing leaflet can be identified by computed tomography (CT). Emergent surgical correction is mandatory. We report a case of fractured escape of Edward-Duromedics mitral valve 27 years after the surgery. The patient presented with symptoms of acute decompensated heart failure and cardiogenic shock. She was instantly intubated and mechanically ventilated. After prompt evaluation including transthoracic echocardiography and CT, the escape of the leaflet was confirmed. The patient underwent emergent surgery for replacement of the damaged prosthetic valves immediately. Eleven days after the surgery, the dislodged leaflet in iliac artery was removed safely and the patient recovered well. PMID:23837121

  6. Active combustion flow modulation valve

    Science.gov (United States)

    Hensel, John Peter; Black, Nathaniel; Thorton, Jimmy Dean; Vipperman, Jeffrey Stuart; Lambeth, David N; Clark, William W

    2013-09-24

    A flow modulation valve has a slidably translating hollow armature with at least one energizable coil wound around and fixably attached to the hollow armature. The energizable coil or coils are influenced by at least one permanent magnet surrounding the hollow armature and supported by an outer casing. Lorentz forces on the energizable coils which are translated to the hollow armature, increase or decrease the flow area to provide flow throttling action. The extent of hollow armature translation depends on the value of current supplied and the direction of translation depends on the direction of current flow. The compact nature of the flow modulation valve combined with the high forces afforded by the actuator design provide a flow modulation valve which is highly responsive to high-rate input control signals.

  7. Evaluation of mispositioned ECCS valves

    International Nuclear Information System (INIS)

    Hill, R.A.; O'Brien, J.F.; McIntire, D.C.; Barlow, R.T.

    1977-09-01

    In October of 1975, Westinghouse submitted NS-CE-787, dated October 17, 1975, to the Nuclear Regulatory Commission (NRC) and entered into discussions with them concerning the spurious movement of certain motor-operated valves (MOV's) in the Emergency Core Cooling System (ECCS) to a position defeating the ECCS function at a time when this function is required. On November 25, 1975, the discussion turned to the possible movement of a manually controlled, motor-operated valve due to a fault in its electrical circuitry and the NRC staff expressed concerns about other possible failure modes that might lead to such a valve movement. The NRC meeting minutes document these concerns. This report is an item-by-item response to the concerns expressed by the NRC staff at that meeting and incorporates the original electrical fault analysis

  8. 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.

  9. 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

    2016-06-20

    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.

  10. 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...

  11. Early clinical outcome of aortic transcatheter valve-in-valve implantation in the Nordic countries

    DEFF Research Database (Denmark)

    Ihlberg, Leo; Nissen, Henrik Hoffmann; Nielsen, Niels Erik

    2013-01-01

    Transcatheter valve-in-valve implantation has emerged as an option, in addition to reoperative surgical aortic valve replacement, to treat failed biologic heart valve substitutes. However, the clinical experience with this approach is still limited. We report the comprehensive experience...

  12. Intro to Valve Guide Reconditioning. Automotive Mechanics. Valves. Instructor's Guide [and] Student Guide.

    Science.gov (United States)

    Horner, W.

    This instructional package, one in a series of individualized instructional units on tools and techniques for repairing worn valve guides in motor vehicles, provides practical experience for students in working on cylinder heads. Covered in the module are reaming valve guides that are oversized to match a new oversized valve, reaming valve guides…

  13. Infective Endocarditis of the Aortic Valve with Anterior Mitral Valve Leaflet Aneurysm

    NARCIS (Netherlands)

    Tomsic, Anton; Li, Wilson W. L.; van Paridon, Marieke; Bindraban, Navin R.; de Mol, Bas A. J. M.

    2016-01-01

    Mitral valve leaflet aneurysm is a rare and potentially devastating complication of aortic valve endocarditis. We report the case of a 48-year-old man who had endocarditis of the native aortic valve and a concomitant aneurysm of the anterior mitral valve leaflet. Severe mitral regurgitation occurred

  14. Disposal of bead ion exchange resin wastes

    International Nuclear Information System (INIS)

    Gay, R.L.; Granthan, L.F.

    1985-01-01

    Bead ion exchange resin wastes are disposed of by a process which involves spray-drying a bead ion exchange resin waste in order to remove substantially all of the water present in such waste, including the water on the surface of the ion exchange resin beads and the water inside the ion exchange resin beads. The resulting dried ion exchange resin beads can then be solidified in a suitable solid matrix-forming material, such as a polymer, which solidifies to contain the dried ion exchange resin beads in a solid monolith suitable for disposal by burial or other conventional means

  15. Radioactive waste disposal package

    Science.gov (United States)

    Lampe, Robert F.

    1986-11-04

    A radioactive waste disposal package comprising a canister for containing vitrified radioactive waste material and a sealed outer shell encapsulating the canister. A solid block of filler material is supported in said shell and convertible into a liquid state for flow into the space between the canister and outer shell and subsequently hardened to form a solid, impervious layer occupying such space.

  16. Manufacture of disposal canisters

    International Nuclear Information System (INIS)

    Nolvi, L.

    2009-12-01

    The report summarizes the development work carried out in the manufacturing of disposal canister components, and present status, in readiness for manufacturing, of the components for use in assembly of spent nuclear fuel disposal canister. The disposal canister consist of two major components: the nodular graphite cast iron insert and overpack of oxygen-free copper. The manufacturing process for copper components begins with a cylindrical cast copper billet. Three different manufacturing processes i.e. pierce and draw, extrusion and forging are being developed, which produce a seamless copper tube or a tube with an integrated bottom. The pierce and draw process, Posiva's reference method, makes an integrated bottom possible and only the lid requires welding. Inserts for BWR-element are cast with 12 square channels and inserts for VVER 440-element with 12 round channels. Inserts for EPR-elements have four square channels. Casting of BWR insert type has been studied so far. Experience of casting inserts for PWR, which is similar to the EPR-type, has been got in co-operation with SKB. The report describes the processes being developed for manufacture of disposal canister components and some results of the manufacturing experiments are presented. Quality assurance and quality control in manufacture of canister component is described. (orig.)

  17. Oil ''rig'' disposal

    International Nuclear Information System (INIS)

    Anon.

    1996-01-01

    A comparison of the environmental impacts of disposing of the Brent Spar oil platform on land and at sea is presented, with a view to establishing the best decommissioning option in the light of recent controversy. The document is presented as an aid to comprehension of the scientific and engineering issues involved for Members of Parliament. (UK)

  18. Chemical Stockpile Disposal Program

    Energy Technology Data Exchange (ETDEWEB)

    Krummel, J.R.; Policastro, A.J.; Olshansky, S.J.; McGinnis, L.D.

    1990-10-01

    As part of the Chemical Stockpile Disposal Program mandated by Public Law 99--145 (Department of Defense Authorization Act), an independent review is presented of the US Army Phase I environmental report for the disposal program at the Umatilla Depot Activity (UMDA) in Hermiston, Oregon. The Phase I report addressed new and additional concerns not incorporated in the final programmatic environmental impact statement (FPEIS). Those concerns were addressed by examining site-specific data for the Umatilla Depot Activity and by recommending the scope and content of a more detailed site-specific study. This independent review evaluates whether the new site-specific data presented in the Phase I report would alter the decision in favor of on-site disposal that was reached in the FPEIS, and whether the recommendations for the scope and content of the site-specific study are adequate. Based on the methods and assumptions presented in the FPEIS, the inclusion of more detailed site-specific data in the Phase I report does not change the decision reached in the FPEIS (which favored on-site disposal at UMDA). It is recommended that alternative assumptions about meteorological conditions be considered and that site-specific data on water, ecological, socioeconomic, and cultural resources; seismicity; and emergency planning and preparedness be considered explicitly in the site-specific EIS decision-making process. 7 refs., 1 fig.

  19. Nanomaterial disposal by incineration

    Science.gov (United States)

    As nanotechnology-based products enter into widespread use, nanomaterials will end up in disposal waste streams that are ultimately discharged to the environment. One possible end-of-life scenario is incineration. This review attempts to ascertain the potential pathways by which ...

  20. Geological disposal concept hearings

    International Nuclear Information System (INIS)

    1996-01-01

    The article outlines the progress to date on AECL spent-nuclear fuel geological disposal concept. Hearings for discussion, organised by the federal Environmental Assessment Review Panel, of issues related to this type of disposal method occur in three phases, phase I focuses on broad societal issues related to long term management of nuclear fuel waste; phase II will focus on the technical aspects of this method of disposal; and phase III will consist of community visits in New Brunswick, Quebec, Ontario, Manitoba and Saskatchewan. This article provides the events surrounding the first two weeks of phase I hearings (extracted from UNECAN NEWS). In the first week of hearings, where submissions on general societal issues was the focus, there were 50 presentations including those by Natural Resources Canada, Energy Probe, Ontario Hydro, AECL, Canadian Nuclear Society, Aboriginal groups, environmental activist organizations (Northwatch, Saskatchewan Environmental Society, the Inter-Church Uranium Committee, and the Canadian Coalition for Nuclear responsibility). In the second week of hearings there was 33 presentations in which issues related to siting and implementation of a disposal facility was the focus. Phase II hearings dates are June 10-14, 17-21 and 27-28 in Toronto

  1. Plumbing and Sewage Disposal.

    Science.gov (United States)

    Sutliff, Ronald D.; And Others

    This self-study course is designed to familiarize Marine enlisted personnel with the principles of plumbing and sewage disposal used by Marine Hygiene Equipment Operators to perform their mission. The course contains three study units. Each study unit begins with a general objective, which is a statement of what the student should learn from the…

  2. Radwaste treatment and disposal

    International Nuclear Information System (INIS)

    Ehn, L.; Breza, M.; Pekar, A.

    2000-01-01

    In this lecture is given the basic information, that is concerning on the RAW treatment and long term disposal of the treated RAW in repository at Mochovce. Then here is given the basic technical and technological information, that is concerning bituminization, plant, the vitrification unit, center for the RAW-treatment (BSC) and repository at Mochovce. (authors)

  3. Waste disposal package

    Science.gov (United States)

    Smith, M.J.

    1985-06-19

    This is a claim for a waste disposal package including an inner or primary canister for containing hazardous and/or radioactive wastes. The primary canister is encapsulated by an outer or secondary barrier formed of a porous ceramic material to control ingress of water to the canister and the release rate of wastes upon breach on the canister. 4 figs.

  4. Microbial reduction of SO{sub 2} and NO{sub x} as a means of by- product recovery/disposal from regenerable processes for the desulfurization of flue gas. Technical progress report, June 11, 1992--September 11, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Sublette, K.L.

    1992-12-31

    Based on the work described simultaneous SO{sub 2}/No{sub x} removal from flue gas based on direct contact of the gas with SRB and T. denitrificans co-cultures or cultures-in-series has been eliminated as a viable process concept at this time. The technical reasons are as follows: (1) NO inhibition of SO{sub 2} reduction by D. desulfuricans - Although the NO concentrations used in the experiments described above are somewhat higher than that found in a typical flue gas, it is quite possible that at lower NO concentrations (or partial pressures) the inhibiting effects will simply take longer to become apparent. (2) Nitrate suppression of NO removal - As noted previously, the cultivation of T. denitrificans in a microbial flue gas treatment system (either one or two stages) would require sulfide-limiting conditions. Therefore, the electron acceptor must be in excess, requiring nitrate in the T. denitrificans process culture. As shown in experiments described above, nitrate significantly suppresses the removal of NO from a feed gas making simultaneous SO{sub 2}/NO{sub x} removal impractical by microbial means. (3) O{sub 2} inhibition of SO{sub 2} and NO reduction - It has been demonstrated that D. desulfuricans working cultures are tolerant of up to 1.7% O{sub 2} in the feed gas. However, further increases in the O{sub 2} partial pressure in the feed gas resulted in O{sub 2} inhibition of SO{sub 2} reduction. These inhibiting levels of O{sub 2} are comparable to those concentrations found in flue gases (3). Therefore, in any process in which raw flue gas contacts a D. desulfuricans culture marginal stability at best can be expected.

  5. Microbial reduction of SO[sub 2] and NO[sub x] as a means of by- product recovery/disposal from regenerable processes for the desulfurization of flue gas

    Energy Technology Data Exchange (ETDEWEB)

    Sublette, K.L.

    1992-01-01

    Based on the work described simultaneous SO[sub 2]/No[sub x] removal from flue gas based on direct contact of the gas with SRB and T. denitrificans co-cultures or cultures-in-series has been eliminated as a viable process concept at this time. The technical reasons are as follows: (1) NO inhibition of SO[sub 2] reduction by D. desulfuricans - Although the NO concentrations used in the experiments described above are somewhat higher than that found in a typical flue gas, it is quite possible that at lower NO concentrations (or partial pressures) the inhibiting effects will simply take longer to become apparent. (2) Nitrate suppression of NO removal - As noted previously, the cultivation of T. denitrificans in a microbial flue gas treatment system (either one or two stages) would require sulfide-limiting conditions. Therefore, the electron acceptor must be in excess, requiring nitrate in the T. denitrificans process culture. As shown in experiments described above, nitrate significantly suppresses the removal of NO from a feed gas making simultaneous SO[sub 2]/NO[sub x] removal impractical by microbial means. (3) O[sub 2] inhibition of SO[sub 2] and NO reduction - It has been demonstrated that D. desulfuricans working cultures are tolerant of up to 1.7% O[sub 2] in the feed gas. However, further increases in the O[sub 2] partial pressure in the feed gas resulted in O[sub 2] inhibition of SO[sub 2] reduction. These inhibiting levels of O[sub 2] are comparable to those concentrations found in flue gases (3). Therefore, in any process in which raw flue gas contacts a D. desulfuricans culture marginal stability at best can be expected.

  6. Transcatheter aortic valve implantation of the direct flow medical aortic valve with minimal or no contrast

    Energy Technology Data Exchange (ETDEWEB)

    Latib, Azeem, E-mail: alatib@gmail.com [Interventional Cardiology Unit, San Raffaele Scientific Institute and EMO-GVM Centro Cuore Columbus, Milan (Italy); Maisano, Francesco; Colombo, Antonio [Interventional Cardiology Unit, San Raffaele Scientific Institute and EMO-GVM Centro Cuore Columbus, Milan (Italy); Klugmann, Silvio [Azienda Ospedaliera Niguarda Ca Granda, Piazza Ospedale Maggiore 3, Milan (Italy); Low, Reginald; Smith, Thomas [University of California Davis, Davis, CA 95616 (United States); Davidson, Charles [Northwestern Memorial Hospital, Chicago, IL 60611 (United States); Harreld, John H. [Clinical Imaging Analytics, Guerneville, CA (United States); Bruschi, Giuseppe; DeMarco, Federico [Azienda Ospedaliera Niguarda Ca Granda, Piazza Ospedale Maggiore 3, Milan (Italy)

    2014-06-15

    The 18F Direct Flow Medical (DFM) THV has conformable sealing rings, which minimizes aortic regurgitation and permits full hemodynamic assessment of valve performance prior to permanent implantation. During the DISCOVER trial, three patients who were at risk for receiving contrast media, two due to severe CKD and one due to a recent hyperthyroid reaction to contrast, underwent DFM implantation under fluoroscopic and transesophageal guidance without aortography during either positioning or to confirm the final position. Valve positioning was based on the optimal angiographic projection as calculated by the pre-procedural multislice CT scan. Precise optimization of valve position was performed to minimize transvalve gradient and aortic regurgitation. Prior to final implantation, transvalve hemodynamics were assessed invasively and by TEE. The post-procedure mean gradients were 7, 10, 11 mm Hg. The final AVA by echo was 1.70, 1.40 and 1.68 cm{sup 2}. Total aortic regurgitation post-procedure was none or trace in all three patients. Total positioning and assessment of valve performance time was 4, 6, and 12 minutes. Contrast was only used to confirm successful percutaneous closure of the femoral access site. The total contrast dose was 5, 8, 12 cc. Baseline eGFR and creatinine was 28, 22, 74 mL/min/1.73 m{sup 2} and 2.35, 2.98, and 1.03 mg/dL, respectively. Renal function was unchanged post-procedure: eGFR = 25, 35, and 96 mL/min/1.73 m{sup 2} and creatinine = 2.58, 1.99, and 1.03 mg/dL, respectively. In conclusion, the DFM THV provides the ability to perform TAVI with minimal or no contrast. The precise and predictable implantation technique can be performed with fluoro and echo guidance.

  7. Small sodium valve design and operating experience

    International Nuclear Information System (INIS)

    McGough, C.B.

    1974-01-01

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

  8. 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....

  9. 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....

  10. Geological disposal of radioactive wastes

    International Nuclear Information System (INIS)

    Sato, Tsutomu

    2000-01-01

    For disposing method of radioactive wastes, various feasibilities are investigated at every nations and international organizations using atomic energy, various methods such as disposal to cosmic space, disposal to ice sheet at the South Pole and so forth, disposal into ocean bed or its sediments, and disposal into ground have been examined. It is, however, impossible institutionally at present, to have large risk on accident in the disposal to cosmic space, to be prohibited by the South Pole Treaty on the disposal to ice sheet at the South Pole, and to be prohibited by the treaty on prevention of oceanic pollution due to the disposal of wastes and so forth on the disposal into oceanic bed or its sediments (London Treaty). Against them, the ground disposal is thought to be the most powerful method internationally from some reasons shown as follows: no burden to the next generation because of no need in long-term management by human beings; safety based on scientific forecasting; disposal in own nation; application of accumulated technologies on present mining industries, civil engineering, and so forth to construction of a disposal facility; and, possibility to take out wastes again, if required. For the ground disposal, wastes must be buried into the ground and evaluated their safety for long terms. It is a big subject to be taken initiative by engineers on geoscience who have quantified some phenomena in the ground and at ultra long term. (G.K.)

  11. Fast-acting valve actuator

    Science.gov (United States)

    Cho, Nakwon

    1980-01-01

    A fast-acting valve actuator utilizes a spring driven pneumatically loaded piston to drive a valve gate. Rapid exhaust of pressurized gas from the pneumatically loaded side of the piston facilitates an extremely rapid piston stroke. A flexible selector diaphragm opens and closes an exhaust port in response to pressure differentials created by energizing and de-energizing a solenoid which controls the pneumatic input to the actuator as well as selectively providing a venting action to one side of the selector diaphragm.

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

    International Nuclear Information System (INIS)

    Rho, Hyung Joon; Lee, Jee Keun; Choi, Hee Joo

    2008-01-01

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

  13. Manufacturing routes for disposable polymer blood diagnostic microfluidic systems

    DEFF Research Database (Denmark)

    Tosello, Guido; Griffiths, Christian; Azcarate, Sabino

    2008-01-01

    (Multi-Material Micro Manufacture) that are relevant to the technology for disposable polymer parts for Micro-Tele-BioChip (µTBC) medical platforms. Combining two separation mechanisms a novel micro channel design was developed. The separation unit is based on a micro channel bend structure where typical...... channel dimensions are 20 µm for the plasma channel width, and 50-75 µm for the cell channel. The height of all channels is 100 µm. The micro channel bend works simply on physical and hydrodynamic separation mechanisms without integrated actuators like pumps or valves. For the mass-fabrication of low...

  14. Initial Surgical Experience with Aortic Valve Repair: Clinical and Echocardiographic Results

    Directory of Open Access Journals (Sweden)

    Francisco Diniz Affonso da Costa

    Full Text Available Abstract Introduction: Due to late complications associated with the use of conventional prosthetic heart valves, several centers have advocated aortic valve repair and/or valve sparing aortic root replacement for patients with aortic valve insufficiency, in order to enhance late survival and minimize adverse postoperative events. Methods: From March/2012 thru March 2015, 37 patients consecutively underwent conservative operations of the aortic valve and/or aortic root. Mean age was 48±16 years and 81% were males. The aortic valve was bicuspid in 54% and tricuspid in the remaining. All were operated with the aid of intraoperative transesophageal echocardiography. Surgical techniques consisted of replacing the aortic root with a Dacron graft whenever it was dilated or aneurysmatic, using either the remodeling or the reimplantation technique, besides correcting leaflet prolapse when present. Patients were sequentially evaluated with clinical and echocardiographic studies and mean follow-up time was 16±5 months. Results: Thirty-day mortality was 2.7%. In addition there were two late deaths, with late survival being 85% (CI 95% - 68%-95% at two years. Two patients were reoperated due to primary structural valve failure. Freedom from reoperation or from primary structural valve failure was 90% (CI 95% - 66%-97% and 91% (CI 95% - 69%-97% at 2 years, respectively. During clinical follow-up up to 3 years, there were no cases of thromboembolism, hemorrhage or endocarditis. Conclusions: Although this represents an initial series, these data demonstrates that aortic valve repair and/or valve sparing aortic root surgery can be performed with satisfactory immediate and short-term results.

  15. Impact of patient-prosthesis mismatch after transcatheter aortic valve-in-valve implantation in degenerated bioprostheses.

    Science.gov (United States)

    Seiffert, Moritz; Conradi, Lenard; Baldus, Stephan; Knap, Malgorzata; Schirmer, Johannes; Franzen, Olaf; Koschyk, Dietmar; Meinertz, Thomas; Reichenspurner, Hermann; Treede, Hendrik

    2012-03-01

    Transcatheter valve-in-valve implantation is evolving as an alternative to reoperative valve replacement in high-risk patients with degenerated bioprostheses. Nevertheless, hemodynamic performance is limited by the previously implanted xenograft. We report our experience with patient-prosthesis mismatch (PPM) after valve-in-valve implantation in the aortic position. Eleven patients (aged 79.3 ± 6.1 years) received transapical implantation of a balloon-expandable pericardial heart valve into a degenerated bioprosthesis (size, 23.9 ± 1.6 mm; range, 21-27 mm) in the aortic position. All patients were considered high risk for surgical valve replacement (logistic European System for Cardiac Operative Risk Evaluation, 31.8% ± 24.1%). Severe PPM was defined as an indexed effective orifice area less than 0.65 cm(2)/m(2), determined by discharge echocardiography. Severe PPM was evident in 5 patients (group 1) and absent in 6 patients (group 2). Mean transvalvular gradients decreased from 29.2 ± 15.4 mm Hg before implantation to 21.2 ± 9.7 mm Hg at discharge (group 1) and from 28.2 ± 9.0 mm Hg before implantation to 15.2 ± 6.5 mm Hg at discharge (group 2). Indexed effective orifice area increased from 0.5 ± 0.1 cm(2)/m(2) to 0.6 ± 0.1 cm(2)/m(2) and from 0.6 ± 0.3 cm(2)/m(2) to 0.8 ± 0.3 cm(2)/m(2). Aortic regurgitation decreased from grade 2.0 ± 1.1 to 0.4 ± 0.5 overall. No differences in New York Heart Association class improvement or survival during follow-up were observed. One patient required reoperation for symptomatic PPM 426 days after implantation. Valve-in-valve implantation can be performed in high-risk surgical patients to avoid reoperation. However, PPM frequently occurs, making adequate patient selection crucial. Small bioprostheses (body surface area less than 1.8 m(2). Larger prostheses seem to carry a lower risk for PPM. Although no delay in clinical improvement was seen at short-term, 1 PPM-related surgical intervention raises concern regarding

  16. Design and development of innovative passive valves for Nuclear Power Plant applications

    Energy Technology Data Exchange (ETDEWEB)

    Sapra, M.K., E-mail: sapramk@barc.gov.in; Kundu, S.; Pal, A.K.; Vijayan, P.K.; Vaze, K.K.; Sinha, R.K.

    2015-05-15

    by India. For example, the Hot Shutdown Passive Valves (HSPV), developed for the decay heat removal system keep the main heat transport system under hot conditions by passively sensing and controlling the system pressure. Another crucial and important valve which has been successfully developed is the Poison Injection Passive Valve (PIPV) for the Passive Poison Injection System. It not only provides higher reliability, but also ensures safe shutdown of the reactor in case of insider threats or malevolent acts in disabling active shutdown system of the reactor. Recently, an innovative valve called the Accumulator Isolation Passive Valve (AIPV) has been developed for the Emergency Core Cooling System (ECCS), which is engineered to mitigate the consequences of Loss of Coolant Accident (LOCA). During normal operation of the reactor, the pressurized accumulators (55 bar) are kept isolated from the reactor core (70 bar) by means of AIPVs. In case of a LOCA, these passive valves open when the main heat transport system pressure falls to a desired value. For prolonged cooling of the core, these passive valves regulate the discharge in a desired manner. These are non-standard, high pressure and high temperature valves, which are unavailable commercially and hence have to be indigenously designed and developed. This paper primarily deals with the design, development and testing of Accumulator Isolation Passive Valves (AIPV) proposed to be used in the ECCS. A 25 NB size AIPV has been designed and successfully tested at Integral Test Loop (ITL) under simulated reactor conditions. It is a self-acting, ANSI 600 rating valve, which requires no external energy (i.e., neither air nor electrical power). It not only provides passive isolation but also passively controls high pressure liquid discharge through it. The design concept of the valve, functional performance, in situ valve testing methodology and the test results at simulated conditions are discussed.

  17. Low intake valve lift in a port fuel-injected engine

    Energy Technology Data Exchange (ETDEWEB)

    Begg, S.M.; Hindle, M.P.; Cowell, T.; Heikal, M.R. [The Sir Harry Ricardo Laboratories, Centre for Automotive Engineering, Cockcroft Building, University of Brighton, Lewes Road, Brighton, East Sussex, BN2 4GJ (United Kingdom)

    2009-12-15

    A phenomenological study of the airflow and fuel spray interaction in a variable valve gasoline engine is presented. Experiments were performed in a steady-state flow rig fitted with a modified production cylinder head. The intake valve lift was varied manually. The mass flow rates of air and fuel through the test rig were adjusted to match typical engine operating conditions. Particle Image Velocimetry (PIV) and Laser Doppler Anemometry (LDA) measurements of the airflow showed the breakdown of a single, forward tumbling vortex-like structure into a pair of high-speed, turbulent jets at low valve lifts. Two transitional phases in the flow at the valve gap were identified for valve lifts less than 1.5 mm and greater than 3 mm. At the lower limit, a jet flapping instability was recorded. A port fuel injector (PFI) spray was characterised in a quiescent, chamber and within the test rig. High Speed Photography (HSP) and Phase Doppler Anemometry (PDA) were used to measure the effects of varying valve lift upon the fuel droplet characteristics. The in-cylinder measurements showed a reduction in mean droplet diameter of up to 50%, close to the valve gap, for peak valve lifts of less than 3 mm. (author)

  18. Coronary artery disease in patients undergoing valve replacement at a tertiary care cardiac centre

    International Nuclear Information System (INIS)

    Shaikh, A.H.; Hanif, B.; Hasan, K.; Hashmani, S.

    2011-01-01

    To determine the prevalence of coronary artery disease in patients undergoing valve surgery at a tertiary care cardiac centre. The medical records of 144 consecutive patients who underwent mitral, aortic or dual (mitral and aortic) valve replacement surgery at the Tabba Heart Institute between January 2006 to December 2008 were retrospectively reviewed. All patients underwent coronary angiogram. Significant coronary artery disease (CAD) is defined as coronary stenosis of > 50%. There were 74 (51.4%) males and 70 (48.6%) females in the study. The mean age was 51.64 +- 11 years. Of all, 73 (50.7%) underwent mitral valve replacement, 47 (32.6%) had aortic and 24 (16.7%) had dual valve replacement. Out of 144 patients, 99 (68.8%) had 50% stenosis. In patients who had undergone mitral valve replacement (MVR), significant coronary disease was found in 32.9%, whereas in patients who had undergone aortic valve replacement (AVR) and dual valve replacement (DVR) the prevalence of coronary disease was 31.9% and 25% respectively. Our results suggest that the overall prevalence of coronary artery disease in patients undergoing valve surgery in our population is comparable with prevalence reported in international data. (author)

  19. 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 locations: (a) On the suction end and the discharge end of a pump station in a manner that permits isolation...

  20. Porcine Tricuspid Valve Anatomy and Human Compatibility

    DEFF Research Database (Denmark)

    Waziri, Farhad; Lyager Nielsen, Sten; Hasenkam, J. Michael

    2016-01-01

    before clinical use. The study aim was to evaluate and compare the tricuspid valve anatomy of porcine and human hearts. METHODS: The anatomy of the tricuspid valve and the surrounding structures that affect the valve during a cardiac cycle were examined in detail in 100 fresh and 19 formalin...

  1. Valve-sparing aortic root replacement†

    NARCIS (Netherlands)

    Koolbergen, David R.; Manshanden, Johan S. J.; Bouma, Berto J.; Blom, Nico A.; Mulder, Barbara J. M.; de Mol, Bas A. J. M.; Hazekamp, Mark G.

    2015-01-01

    To evaluate our results of valve-sparing aortic root replacement and associated (multiple) valve repair. From September 2003 to September 2013, 97 patients had valve-sparing aortic root replacement procedures. Patient records and preoperative, postoperative and recent echocardiograms were reviewed.

  2. Solving the problem of valve stem leakage

    International Nuclear Information System (INIS)

    Dixon, D.F.

    1976-01-01

    Engineering solutions to valve stem leakage, in systems carrying expensive heavy water under pressure, have progressed from changing packing brands (failure) to leak collection (partial success) to elimination of small packed valves and an improved valve packing strategy involving stable packing materials, live Belleville spring-loading of packing, and issuance of a detailed stuffing box specification (success). (E.C.B.)

  3. 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..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Steam Generators § 229.109 Safety valves. Every steam generator shall be equipped with at least two safety valves that have a...

  4. 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.

  5. Valve Corporation: Strategy Tipping Points and Thresholds

    OpenAIRE

    Teppo Felin

    2015-01-01

    Valve Corporation represents an intriguing case study of flat structure and self organization (Puranam & Håkonsson, 2015; Valve, 2012).  The structures and practices of Valve of course are not new. But the company provides an interesting experiment and illustration that powerfully highlights how organizational design can impact individual and collective behavior, strategy and performance.

  6. Valve Corporation: Strategy Tipping Points and Thresholds

    Directory of Open Access Journals (Sweden)

    Teppo Felin

    2015-06-01

    Full Text Available Valve Corporation represents an intriguing case study of flat structure and self organization (Puranam & Håkonsson, 2015; Valve, 2012.  The structures and practices of Valve of course are not new. But the company provides an interesting experiment and illustration that powerfully highlights how organizational design can impact individual and collective behavior, strategy and performance.

  7. Sequential transcatheter aortic valve implantation due to valve dislodgement

    DEFF Research Database (Denmark)

    Campante Teles, Rui; Costa, Cátia; Almeida, Manuel

    2017-01-01

    Transcatheter aortic valve implantation (TAVI) has become an important treatment in high surgical risk patients with severe aortic stenosis (AS), whose complications need to be managed promptly. The authors report the case of an 86-year-old woman presenting with severe symptomatic AS, rejected...

  8. Decommissioning and disposal costs in Switzerland

    International Nuclear Information System (INIS)

    Zurkinden, Auguste

    2003-01-01

    Introduction Goal: Secure sufficient financial resources. Question: How much money is needed? Mean: Concrete plans for decommissioning and waste disposal. - It is the task of the operators to elaborate these plans and to evaluate the corresponding costs - Plans and costs are to be reviewed by the authorities Decommissioning Plans and Costs - Comprise decommissioning, dismantling and management (including disposal) of the waste. - New studies 2001 for each Swiss nuclear power plant (KKB 2 x 380 MWe, KKM 370 MWe, KKG 1020 MWe, KKL 1180 MWe). - Studies performed by NIS (D). - Last developments taken into account (Niederaichbach, Gundremmingen, Kahl). Decommissioning: Results and Review Results: Total cost estimates decreasing (billion CHF) 1994 1998 2001 13.7 13.1 11.8 Lower costs for spent fuel conditioning and BE/HAA/LMA repository (Opalinus Clay) Split in 2025: 5.6 bil. CHF paid by NPP 6.2 billion CHF in Fund Review: Concentrates on disposal, ongoing

  9. Supra-annular valve strategy for an early degenerated transcatheter balloon-expandable heart valve.

    Science.gov (United States)

    Kamioka, Norihiko; Caughron, Hope; Corrigan, Frank; Block, Peter; Babaliaros, Vasilis

    2018-01-23

    Currently, there are no recommendations regarding the selection of valve type for a transcatheter heart valve (THV)-in-THV procedure. A supra-annular valve design may be superior in that it results in a larger effective orifice area and may have a lower chance of valve thrombosis after THV-in-THV. In this report, we describe the use of a supra-annular valve strategy for an early degenerated THV. © 2018 Wiley Periodicals, Inc.

  10. Aortic valve insufficiency in the teenager and young adult: the role of prosthetic valve replacement.

    Science.gov (United States)

    Bradley, Scott M

    2013-10-01

    The contents of this article were presented in the session "Aortic insufficiency in the teenager" at the congenital parallel symposium of the 2013 Society of Thoracic Surgeons (STS) annual meeting. The accompanying articles detail the approaches of aortic valve repair and the Ross procedure.(1,2) The current article focuses on prosthetic valve replacement. For many young patients requiring aortic valve surgery, either aortic valve repair or a Ross procedure provides a good option. The advantages include avoidance of anticoagulation and potential for growth. In other patients, a prosthetic valve is an appropriate alternative. This article discusses the current state of knowledge regarding mechanical and bioprosthetic valve prostheses and their specific advantages relative to valve repair or a Ross procedure. In current practice, young patients requiring aortic valve surgery frequently undergo valve replacement with a prosthetic valve. In STS adult cardiac database, among patients ≤30 years of age undergoing aortic valve surgery, 34% had placement of a mechanical valve, 51% had placement of a bioprosthetic valve, 9% had aortic valve repair, and 2% had a Ross procedure. In the STS congenital database, among patients 12 to 30 years of age undergoing aortic valve surgery, 21% had placement of a mechanical valve, 18% had placement of a bioprosthetic valve, 30% had aortic valve repair, and 24% had a Ross procedure. In the future, the balance among these options may be altered by design improvements in prosthetic valves, alternatives to warfarin, the development of new patch materials for valve repair, and techniques to avoid Ross autograft failure.

  11. Nasal valve evaluation in the Mexican-Hispanic (mestizo) nose.

    Science.gov (United States)

    Jasso-Ramírez, Elizabeth; Sánchez Y Béjar, Fernando; Arcaute Aizpuru, Fernando; Maulen Radován, Irene E; de la Garza Hesles, Héctor

    2018-04-01

    Our aim in this study was to determine the angle of the internal nasal valve in Mexican patients with the "mestizo nose" feature and without nasal obstructive symptoms. The work was prospective, comparative, and observational in nature and included patients >14 years of age who were seen in the Otolaryngology Department at the Los Angeles Lomas Hospital between April and May 2016. The angle of the internal nasal valve was measured in 30 patients without obstructive symptoms. Endoscopic examination was performed with a 0° endoscope framed with tape at a 13-mm distance from the endoscope's tip, and digital photographs of the internal nasal valve were taken. The measurement of the angle of the internal nasal valve was made in sexagesimal degrees using Golden Ratio v3.1 (2012) software. Statistical analysis was performed using Excel v15.13.3. The angles of the internal nasal valve of the patients were (mean ± standard deviation) 24.07 ± 4.8° for the right nasal cavity and 25.07 ± 5.0° for the left nasal cavity, wider than the angle reported in the normal Caucasian nose established in the literature. According to our results, the Mexican-Hispanic mestizo nose has a wider angle in the internal nasal valve than that considered normal in the literature (10°-15°). We believe it is necessary to undertake a second study and add an airflow resistance measurement with a rhinomanometry procedure so we can compare the results with those in the Caucasian population. © 2018 ARS-AAOA, LLC.

  12. Depth of valve implantation, conduction disturbances and pacemaker implantation with CoreValve and CoreValve Accutrak system for Transcatheter Aortic Valve Implantation, a multi-center study.

    Science.gov (United States)

    Lenders, Guy D; Collas, Valérie; Hernandez, José Maria; Legrand, Victor; Danenberg, Haim D; den Heijer, Peter; Rodrigus, Inez E; Paelinck, Bernard P; Vrints, Christiaan J; Bosmans, Johan M

    2014-10-20

    Transcatheter Aortic Valve Implantation (TAVI) is now considered an indispensable treatment strategy in high operative risk patients with severe, symptomatic aortic stenosis. However, conduction disturbances and the need for Permanent Pacemaker (PPM) implantation after TAVI with the CoreValve prosthesis still remain frequent. We aimed to evaluate the implantation depth, the incidence and predictors of new conduction disturbances, and the need for PPM implantation within the first month after TAVI, using the new Accutrak CoreValve delivery system (ACV), compared to the previous generation CoreValve (non-ACV). In 5 experienced TAVI-centers, a total of 120 consecutive non-ACV and 112 consecutive ACV patients were included (n=232). The mean depth of valve implantation (DVI) was 8.4±4.0 mm in the non-ACV group and 7.1±4.0 mm in the ACV group (p=0.034). The combined incidence of new PPM implantation and new LBBB was 71.2% in the non-ACV group compared to 50.5% in the ACV group (p=0.014). DVI (p=0.002), first degree AV block (p=0.018) and RBBB (p<0.001) were independent predictors of PPM implantation. DVI (p<0.001) and pre-existing first degree AV-block (p=0.021) were identified as significant predictors of new LBBB. DVI is an independent predictor of TAVI-related conduction disturbances and can be reduced by using the newer CoreValve Accutrak delivery system, resulting in a significantly lower incidence of new LBBB and new PPM implantation. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  13. Geological disposal of nuclear waste

    International Nuclear Information System (INIS)

    1979-01-01

    Fourteen papers dealing with disposal of high-level radioactive wastes are presented. These cover disposal in salt deposits, geologic deposits and marine disposal. Also included are papers on nuclear waste characterization, transport, waste processing technology, and safety analysis. All of these papers have been abstracted and indexed

  14. Impact of pannus formation on hemodynamic dysfunction of prosthetic aortic valve: pannus extent and its relationship to prosthetic valve motion and degree of stenosis.

    Science.gov (United States)

    Koo, Hyun Jung; Ha, Hojin; Kang, Joon-Won; Kim, Jeong A; Song, Jae-Kwan; Kim, Hwa Jung; Lim, Tae-Hwan; Yang, Dong Hyun

    2018-02-19

    Although pannus is an important cause of prosthetic valve dysfunction, the minimum pannus size that can induce hemodynamic dysfunction has not yet been determined. This study investigated the correlation between the limitation of motion (LOM) of the prosthetic valve and pannus extent and determined the pannus extent that could induce severe aortic stenosis. This study included 49 patients who underwent mechanical aortic valve replacement (AVR) and showed pannus on cardiac computed tomography (CT). Pannus width, ratio of pannus width to valve diameter, pannus area, effective orifice area, encroachment ratio by pannus, pannus involvement angle and percent LOM of mechanical valves were evaluated on CT. Transvalvular peak velocity (TPV) and transvalvular pressure gradient (TPG) were measured by transesophageal echocardiography to determine the degree of aortic stenosis. The relationship between percent LOM of the prosthetic valve and pannus extent and the cut-off of pannus extent required to induce severe aortic stenosis were evaluated. The mean interval between AVR and pannus formation was 11 years and was longer in patients with than without severe aortic stenosis (14.0 vs. 7.3 years). On CT, the percent LOM of the prosthetic valve was significantly associated with the extent of pannus only in patients with pannus involvement angle > 180° (r = 0.55-0.68, P Pannus width, effective orifice area, and encroachment ratio were significantly associated with increased TPV and TPG (r = 0.51-0.62, P Pannus width > 3.5 mm, pannus width/valve inner diameter > 0.15, and encroachment ratio > 0.14 were significantly associated with severe aortic stenosis (TPV > 4 m/s; mean TPG ≥ 35 mmHg), with c-indices of 0.74-079 (P pannus extent parameters are good indicators of significant hemodynamic changes with increased TPV and mean TPG.

  15. Cine MR imaging in mitral valve prolapse

    International Nuclear Information System (INIS)

    Kumai, Toshihiko

    1993-01-01

    This study was undertaken to assess the ability of cine MR imaging to evaluate the direction, timing, and severity of mitral regurgitation in patients with mitral valve prolapse (MVP). The population of this study was 33 patients with MVP diagnosed by two-dimensional echocardiography and 10 patients with rheumatic mitral valve disease (MSR) for comparison. 7 patients with MVP and 5 with MSR had atrial fibrillation and/or history of congestive heart failure as complications. Mitral regurgitation was graded for severity by color Doppler flow imaging in all patients. Direction and size of systolic flow void in the left atrium were analyzed by contiguous multilevel cine MR images and the maximum volumes of flow void and left atrium were measured. Although flow void was found at the center of the left atrium in most of MSR, it was often directed along the postero-caudal atrial wall in anterior leaflet prolapse and along the anterocranial atrial wall in posterior leaflet prolapse. In MVP, the maximum volume of flow void was often seen in late systole. The maximum volume of flow void and that of left atrium were significantly larger in patients with atrial fibrillation and/or history of congestive heart failure. The length and volume of flow void were increased with clinical severity and degree of regurgitation determined by color Doppler flow imaging. Thus cine MR imaging provides a useful means for detection and semiquantitative evaluation of mitral regurgitation in subjects with MVP. (author)

  16. W-12 valve pit decontamination demonstration

    International Nuclear Information System (INIS)

    Benson, C.E.; Parfitt, J.E.; Patton, B.D.

    1995-12-01

    Waste tank W-12 is a tank in the ORNL Low-Level Liquid Waste (LLLW) system that collected waste from Building 3525. Because of a leaking flange in the discharge line from W-12 to the evaporator service tank (W-22) and continual inleakage into the tank from an unknown source, W-12 was removed from service to comply with the Federal Facilities Agreement requirement. The initial response was to decontaminate the valve pit between tank W-12 and the evaporator service tank (W-22) to determine if personnel could enter the pit to attempt repair of the leaking flange. Preventing the spread of radioactive contamination from the pit to the environment and to other waste systems was of concern during the decontamination. The drain in the pit goes to the process waste system; therefore, if high-level liquid waste were generated during decontamination activities, it would have to be removed from the pit by means other than the available liquid waste connection. Remote decontamination of W-12 was conducted using the General Mills manipulator bridge and telescoping trolley and REMOTEC RM-10 manipulator. The initial objective of repairing the leaking flange was not conducted because of the repair uncertainty and the unknown tank inleakage. Rather, new piping was installed to empty the W-12 tank that would bypass the valve pit and eliminate the need to repair the flange. The radiological surveys indicated that a substantial decontamination factor was achieved

  17. Optothermally actuated capillary burst valve

    DEFF Research Database (Denmark)

    Eriksen, Johan; Bilenberg, Brian; Kristensen, Anders

    2017-01-01

    be burst by raising the temperature due to the temperature dependence of the fluid surface tension. We address individual valves by using a local heating platform based on a thin film of near infrared absorber dye embedded in the lid used to seal the microfluidic device [L. H. Thamdrup et al., Nano Lett...

  18. Spring valve for well completion

    Energy Technology Data Exchange (ETDEWEB)

    Gorbatov, P T

    1966-07-22

    A spring-loaded valve for well completion consists of a housing with a spring-loaded closing element. In order to protect the closing element from corrosion which might lower the pressure drop, the closing element is made in the form of a piston. It is tightly connected with sealing elements. The housing has orifices, overlapping the piston in the initial position.

  19. 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.

  20. Evaluation of a novel PTFE material for use as a means for separation and preconcentration of trace levels of metal ions in sequential injection (SI) and sequential injection lab-on-valve (SI-LOV) systems. Determination of cadmium (II) with detection by electrothermal atomic absorption spectrometry

    DEFF Research Database (Denmark)

    Long, Xiangbao; Chomchoei, Roongrat; Hansen, Elo Harald

    2004-01-01

    with an external packed column and in a sequential injection lab-on-valve (SI-LOV) system. Employed for the determination of cadmium(II), complexed with diethyldithiophosphate (DDPA), and detection by electrothermal atomic absorption spectrometry (ETAAS), its performance was compared to that of a previously used...

  1. Preliminary disposal limits, plume interaction factors, and final disposal limits

    Energy Technology Data Exchange (ETDEWEB)

    Flach, G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2018-01-11

    In the 2008 E-Area Performance Assessment (PA), each final disposal limit was constructed as the product of a preliminary disposal limit and a plume interaction factor. The following mathematical development demonstrates that performance objectives are generally expected to be satisfied with high confidence under practical PA scenarios using this method. However, radionuclides that experience significant decay between a disposal unit and the 100-meter boundary, such as H-3 and Sr-90, can challenge performance objectives, depending on the disposed-of waste composition, facility geometry, and the significance of the plume interaction factor. Pros and cons of analyzing single disposal units or multiple disposal units as a group in the preliminary disposal limits analysis are also identified.

  2. Guidelines for valves in tritium service

    International Nuclear Information System (INIS)

    Weaver, W.W.

    1994-01-01

    Some undesirable practices and misapplications that caused valve-related failures are examined, and future courses of action are recommended to avoid repetition of these events. Desirable valve characteristics and practices that should be considered when selecting valves for use in tritium service are also discussed. Supporting logic for the desirability of these features is presented by discussing the mechanisms of valve degradation followed by examples of related events. Desirable valve and system features and operational actions are grouped into two categories: strongly recommended and recommended. 13 refs., 1 fig

  3. Valve assembly having remotely replaceable bearings

    International Nuclear Information System (INIS)

    Johnson, E.R.; Tanner, D.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

  4. Clinical Implication of Transaortic Mitral Pannus Removal During Repeat Cardiac Surgery for Patients With Mechanical Mitral Valve.

    Science.gov (United States)

    Park, Byungjoon; Sung, Kiick; Park, Pyo Won

    2018-01-25

    This study aimed to evaluate the safety and feasibility of transaortic mitral pannus removal (TMPR).Methods and Results:Between 2004 and 2016, 34 patients (median age, 57 years; 30 women) with rheumatic disease underwent pannus removal on the ventricular side of a mechanical mitral valve through the aortic valve during reoperation. The median time interval from the previous surgery was 14 years. TMPR was performed after removal of the mechanical aortic valve (n=21) or diseased native aortic valve (n=11). TMPR was performed in 2 patients through a normal aortic valve. The mitral transprosthetic mean pressure gradient (TMPG) was ≥5 mmHg in 11 patients, including 3 with prosthetic valve malfunction. Prophylactic TMPR was performed in 23 patients. There were no early deaths. Concomitant operations included 22 tricuspid valve surgeries (13 replacements, 15 repairs) and 32 aortic valve replacements (24 repeats, 8 primary). The mean gradient in patients who had mitral TMPG ≥5 mmHg was significantly decreased from 6.46±1.1 to 4.37±1.17 mmHg at discharge (Ppannus overgrowth in such valves.

  5. Disposal of fly ash

    International Nuclear Information System (INIS)

    Singh, B.; Foley, C.

    1991-01-01

    Theoretical arguments and pilot plant results have shown that the transport of fly-furnace ash from the power station to the disposal area as a high concentration slurry is technically viable and economically attractive. Further, lack of free water, when transported as a high concentration slurry, offers significant advantages in environmental management and rehabilitation of the disposal site. This paper gives a basis for the above observations and discusses the plans to exploit the above advantages at the Stanwell Power Station. (4 x 350 MWe). This will be operated by the Queensland Electricity Commission. The first unit is to come into operation in 1992 and other units are to follow progressively on a yearly basis

  6. Nuclear waste disposal

    International Nuclear Information System (INIS)

    Hare, Tony.

    1990-01-01

    The Save Our Earth series has been designed to appeal to the inquiring minds of ''planet-friendly'' young readers. There is now a greater awareness of environmental issues and an increasing concern for a world no longer able to tolerate the onslaught of pollution, the depletion of natural resources and the effects of toxic chemicals. Each book approaches a specific topic in a way that is exciting and thought-provoking, presenting the facts in a style that is concise and appropriate. The series aims to demonstrate how various environmental subjects relate to our lives, and encourages the reader to accept not only responsibility for the planet, but also for its rescue and restoration. This volume, on nuclear waste disposal, explains how nuclear energy is harnessed in a nuclear reactor, what radioactive waste is, what radioactivity is and its effects, and the problems and possible solutions of disposing of nuclear waste. An awareness of the dangers of nuclear waste is sought. (author)

  7. Bentall procedure using cryopreserved valved aortic homografts: mid- to long-term results.

    Science.gov (United States)

    Christenson, Jan T; Sierra, Jorge; Trindade, Pedro T; Dominique, Didier; Kalangos, Afksendiyos

    2004-01-01

    The Bentall procedure is the standard operation for patients who have lesions of the ascending aorta associated with aortic valve disease. In many cases, however, mechanical prosthetic conduits are not suitable. There are few reports in the English-language medical literature concerning the mid- to long-term outcome of Bentall operations with cryopreserved homografts. Therefore, we reviewed our experience with this procedure and valved homografts. From January 1997 through December 2002, 21 patients underwent a Bentall operation with cryopreserved homografts at our institution. There were 14 males and 7 females; the mean age was 36 +/- 21 years (range, 15-74 years). Eleven patients had undergone previous aortic valve surgery. All patients had aortic dilatation or aneurysms involving the ascending aorta. Indications for surgery included aortic valve stenosis or insufficiency, and aortic valve endocarditis (native valve or prosthetic). One patient had Takayasu's arteritis and 3 had Marfan syndrome. There was 1 hospital death (due to sepsis), but no other major postoperative complications. The mean hospital stay was 14 +/- 7 days. Follow-up echocardiographic and computed tomographic scans were performed yearly. The mean follow-up was 34 months (6-72 months). Follow-up imaging revealed no calcifications or degenerative processes related to the homograft. Four patients had minimal valve regurgitation. Two patients died during follow-up. The 3-year actuarial survival rate was 85.7%. Our data suggest that the Bentall procedure with a valved homograft conduit is a safe procedure with excellent mid- to long-term results, comparable to results reported with aortic valve replacement with a homograft.

  8. Whither nuclear waste disposal?

    International Nuclear Information System (INIS)

    Cotton, T.A.

    1990-01-01

    With respect to the argument that geologic disposal has failed, I do not believe that the evidence is yet sufficient to support that conclusion. It is certainly true that the repository program is not progressing as hoped when the Nuclear Waste Policy Act of 1982 established a 1998 deadline for initial operation of the first repository. The Department of Energy (DOE) now expects the repository to be available by 2010, and tat date depends upon a finding that the Yucca Mountain site - the only site that DOE is allowed by law to evaluate - is in fact suitable for use. Furthermore, scientific evaluation of the site to determine its suitability is stopped pending resolution of two lawsuits. However, I believe it is premature to conclude that the legal obstacles are insuperable, since DOE just won the first of the two lawsuits, and chances are good it will win the second. The concept of geologic disposal is still broadly supported. A recent report by the Board on Radioactive Waste Management of the National Research Council noted that 'There is a worldwide scientific consensus that deep geological disposal, the approach being followed in the United States, is the best option for disposing of high-level radioactive waste'. The U.S. Nuclear Regulatory Commission (USNRC) recently implicitly endorsed this view in adopting an updated Waste Confidence position that found confidence that a repository could be available in the first quarter of the next century - sufficient time to allow for rejection of Yucca Mountain and evaluation of a new site

  9. Disposal of radioactive wastes

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1960-11-15

    A discussion on the disposal of radioactive wastes was held in Vienna on 20 September 1960. The three scientists who participated in the discussion were Mr. Harry Brynielsson (Sweden), Head of the Swedish Atomic Energy Company; Mr. H. J. Dunster (United Kingdom), Health Physics Adviser to the United Kingdom Atomic Energy Authority; and Mr. Leslie Silverman (United States), Professor of Harvard University, and Chairman of the US AEC Advisory Committee on Reactor Safeguards, as well as consultant on air cleaning

  10. Whither nuclear waste disposal?

    Energy Technology Data Exchange (ETDEWEB)

    Cotton, T A [JK Research Associates, Silver Spring, MD (United States)

    1990-07-01

    With respect to the argument that geologic disposal has failed, I do not believe that the evidence is yet sufficient to support that conclusion. It is certainly true that the repository program is not progressing as hoped when the Nuclear Waste Policy Act of 1982 established a 1998 deadline for initial operation of the first repository. The Department of Energy (DOE) now expects the repository to be available by 2010, and tat date depends upon a finding that the Yucca Mountain site - the only site that DOE is allowed by law to evaluate - is in fact suitable for use. Furthermore, scientific evaluation of the site to determine its suitability is stopped pending resolution of two lawsuits. However, I believe it is premature to conclude that the legal obstacles are insuperable, since DOE just won the first of the two lawsuits, and chances are good it will win the second. The concept of geologic disposal is still broadly supported. A recent report by the Board on Radioactive Waste Management of the National Research Council noted that 'There is a worldwide scientific consensus that deep geological disposal, the approach being followed in the United States, is the best option for disposing of high-level radioactive waste'. The U.S. Nuclear Regulatory Commission (USNRC) recently implicitly endorsed this view in adopting an updated Waste Confidence position that found confidence that a repository could be available in the first quarter of the next century - sufficient time to allow for rejection of Yucca Mountain and evaluation of a new site.

  11. Disposal of radioactive waste

    International Nuclear Information System (INIS)

    Critchley, R.J.; Swindells, R.J.

    1984-01-01

    A method and apparatus for charging radioactive waste into a disposable steel drum having a plug type lid. The drum is sealed to a waste dispenser and the dispenser closure and lid are withdrawn into the dispenser in back-to-back manner. Before reclosing the dispenser the drum is urged closer to it so that on restoring the dispenser closure to the closed position the lid is pressed into the drum opening

  12. Radium bearing waste disposal

    International Nuclear Information System (INIS)

    Tope, W.G.; Nixon, D.A.; Smith, M.L.; Stone, T.J.; Vogel, R.A.; Schofield, W.D.

    1995-01-01

    Fernald radium bearing ore residue waste, stored within Silos 1 and 2 (K-65) and Silo 3, will be vitrified for disposal at the Nevada Test Site (NTS). A comprehensive, parametric evaluation of waste form, packaging, and transportation alternatives was completed to identify the most cost-effective approach. The impacts of waste loading, waste form, regulatory requirements, NTS waste acceptance criteria, as-low-as-reasonably-achievable principles, and material handling costs were factored into the recommended approach

  13. Disposing of fluid wastes

    International Nuclear Information System (INIS)

    Bradley, J.S.

    1984-01-01

    Toxic liquid waste, eg liquid radioactive waste, is disposed of by locating a sub-surface stratum which, before removal of any fluid, has a fluid pressure in the pores thereof which is less than the hydrostatic pressure which is normal for a stratum at that depth in the chosen area, and then feeding the toxic liquid into the stratum at a rate such that the fluid pressure in the stratum never exceeds the said normal hydrostatic pressure. (author)

  14. Rock disposal problems identified

    Energy Technology Data Exchange (ETDEWEB)

    Knox, R

    1978-06-01

    Mathematical models are the only way of examining the return of radioactivity from nuclear waste to the environment over long periods of time. Work in Britain has helped identify areas where more basic data is required, but initial results look very promising for final disposal of high level waste in hard rock repositories. A report by the National Radiological Protection Board of a recent study, is examined.

  15. Repeat transcatheter aortic valve implantation using a latest generation balloon-expandable device for treatment of failing transcatheter heart valves.

    Science.gov (United States)

    Schaefer, Andreas; Treede, Hendrik; Seiffert, Moritz; Deuschl, Florian; Schofer, Niklas; Schneeberger, Yvonne; Blankenberg, Stefan; Reichenspurner, Hermann; Schaefer, Ulrich; Conradi, Lenard

    2016-01-15

    Paravalvular leakage (PVL) is a known complication of transcatheter aortic valve implantation (TAVI) and is associated with poor outcome. Besides balloon-post-dilatation, valve-in-valve (ViV) procedures can be taken into consideration to control this complication. Herein we present initial experience with use of the latest generation balloon-expandable Edwards Sapien 3® (S3) transcatheter heart valve (THV) for treatment of failing THVs. Between 01/2014 and 12/2014 three patients (two male, age: 71-80 y, log EUROScore I: 11.89 - 32.63) with failing THVs were refered to our institution for further treatment. THV approach with secondary implantation of an S3 was chosen after mutual agreement of the local interdisciplinary heart team at an interval of 533-1119 days from the index procedure. The performed procedures consisted of: S3 in Sapien XT, JenaValve and CoreValve. Successful transfemoral implantation with significant reduction of PVL was achieved in all cases. No intraprocedural complications occurred regarding placement of the S3 with a postprocedural effective orifice area (EOA) of 1.5-2.5 cm(2) and pressure gradients of max/mean 14/6-36/16 mmHg. 30-day mortality was 0%. At the latest follow-up of 90-530 days, all patients are alive and well with satisfactory THV function. Regarding VARC-2 criteria one major bleeding and one TIA was reported. In the instance of moderate or severe aortic regurgitation after TAVI, S3 ViV deployment is an excellent option to reduce residual regurgitation to none or mild. For further assertions concerning functional outcomes long-term results have to be awaited.

  16. Community syringe collection and disposal policies in 16 states.

    Science.gov (United States)

    Turnberg, Wayne L; Jones, T Stephen

    2002-01-01

    To review laws, regulations, and guidelines that affect the collection and disposal of hypodermic needles, syringes, and lancets used outside of professional health care settings (hereafter referred to as "community syringes"). Law and policy analysis. Alabama, California, Florida, Georgia, Hawaii, Massachusetts, Michigan, Minnesota, New Jersey, New York, Ohio, Oregon, Rhode Island, South Carolina, Washington, and Wisconsin. Information on syringe collection and disposal in the community was gathered from federal and state records and state agency personnel. Legally permissible means of syringe collection and disposal available to persons in the community injecting medical treatments and injection drug users. Laws, regulations, or guidelines in 13 states allowed community syringes to be legally discarded in household trash; guidelines for in-trash disposal varied among the states. Only 6 states had laws or regulations that specifically addressed community syringe collection. In 10 states, infectious waste laws and regulations that apply to medical facilities such as clinics would also apply to community syringe collection sites. In the 16 states studied, laws, regulations, and guidelines relating to community syringe collection and disposal were somewhat inconsistent and confusing and presented potential barriers to safe disposal. States should consider amending laws, regulations, and guidelines to promote community syringe collection programs. A national effort is needed to achieve consistent community syringe collection and disposal laws and guidelines for all states. Pharmacists can aid in safe syringe disposal by counseling their patients about safe disposal, providing or selling sharps containers, and accepting used syringes for safe disposal. Pharmacists can join other interested groups in advocating clarification of disposal laws and regulations that favor community programs designed to keep syringes out of the trash so that they can be disposed of as

  17. Disposal of spent fuel

    International Nuclear Information System (INIS)

    Blomeke, J.O.; Ferguson, D.E.; Croff, A.G.

    1978-01-01

    Based on preliminary analyses, spent fuel assemblies are an acceptable form for waste disposal. The following studies appear necessary to bring our knowledge of spent fuel as a final disposal form to a level comparable with that of the solidified wastes from reprocessing: 1. A complete systems analysis is needed of spent fuel disposition from reactor discharge to final isolation in a repository. 2. Since it appears desirable to encase the spent fuel assembly in a metal canister, candidate materials for this container need to be studied. 3. It is highly likely that some ''filler'' material will be needed between the fuel elements and the can. 4. Leachability, stability, and waste-rock interaction studies should be carried out on the fuels. The major disadvantages of spent fuel as a disposal form are the lower maximum heat loading, 60 kW/acre versus 150 kW/acre for high-level waste from a reprocessing plant; the greater long-term potential hazard due to the larger quantities of plutonium and uranium introduced into a repository; and the possibility of criticality in case the repository is breached. The major advantages are the lower cost and increased near-term safety resulting from eliminating reprocessing and the treatment and handling of the wastes therefrom

  18. Greater-confinement disposal

    International Nuclear Information System (INIS)

    Trevorrow, L.E.; Schubert, J.P.

    1989-01-01

    Greater-confinement disposal (GCD) is a general term for low-level waste (LLW) disposal technologies that employ natural and/or engineered barriers and provide a degree of confinement greater than that of shallow-land burial (SLB) but possibly less than that of a geologic repository. Thus GCD is associated with lower risk/hazard ratios than SLB. Although any number of disposal technologies might satisfy the definition of GCD, eight have been selected for consideration in this discussion. These technologies include: (1) earth-covered tumuli, (2) concrete structures, both above and below grade, (3) deep trenches, (4) augered shafts, (5) rock cavities, (6) abandoned mines, (7) high-integrity containers, and (8) hydrofracture. Each of these technologies employ several operations that are mature,however, some are at more advanced stages of development and demonstration than others. Each is defined and further described by information on design, advantages and disadvantages, special equipment requirements, and characteristic operations such as construction, waste emplacement, and closure

  19. Waste and Disposal: Demonstration

    International Nuclear Information System (INIS)

    Neerdael, B.; Buyens, M.; De Bruyn, D.; Volckaert, G.

    2002-01-01

    Within the Belgian R and D programme on geological disposal, demonstration experiments have become increasingly important. In this contribution to the scientific report 2001, an overview is given of SCK-CEN's activities and achievements in the field of large-scale demonstration experiments. In 2001, main emphasis was on the PRACLAY project, which is a large-scale experiment to demonstrate the construction and the operation of a gallery for the disposal of HLW in a clay formation. The PRACLAY experiment will contribute to enhance understanding of water flow and mass transport in dense clay-based materials as well as to improve the design of the reference disposal concept. In the context of PRACLAY, a surface experiment (OPHELIE) has been developed to prepare and to complement PRACLAY-related experimental work in the HADES Underground Research Laboratory. In 2001, efforts were focussed on the operation of the OPHELIE mock-up. SCK-CEN also contributed to the SELFRAC roject which studies the self-healing of fractures in a clay formation

  20. [Tricuspid valve insufficiency: what should be done?].

    Science.gov (United States)

    von Segesser, L K; Stauffer, J C; Delabays, A; Chassot, P G

    1998-12-01

    Tricuspid regurgitation is relatively common. Due to the progress made in echocardiography, its diagnosis is in general made readily and in reliable fashion. Basically one has to distinguish between functional tricuspid valve regurgitation due to volume and/or pressure overload of the right ventricle with intact valve structures versus tricuspid valve regurgitation due to pathologic valve structures. The clear identification of the regurgitation mechanism is of prime importance for the treatment. Functional tricuspid valve regurgitation can often be improved by medical treatment of heart failure, and eventually a tricuspid valve plasty can solve the problem. However, the presence of pathologic tricuspid valve structures makes in general more specific plastic surgical procedures and even prosthetic valve replacements necessary. A typical example for a structural tricuspid valve regurgitation is the case of a traumatic papillary muscle rupture. Due to the sudden onset, this pathology is not well tolerated and requires in general surgical reinsertion of the papillary muscle. In contrast, tricuspid valve regurgitation resulting from chronic pulmonary embolism with pulmonary artery hypertension, can be improved by pulmonary artery thrombendarteriectomy and even completely cured with an additional tricuspid annuloplasty. However, tricuspid regurgitations due to terminal heart failure are not be addressed with surgery directed to tricuspid valve repair or replacement. Heart transplantation, dynamic cardiomyoplasty or mechanical circulatory support should be evaluated instead.

  1. Valve for closing a steam line

    International Nuclear Information System (INIS)

    Meyer, W.; Potrykus, G.

    1976-01-01

    Instead of several control elements, the quick-closing valve, especially in the main-steam line between steam generator and turbine of a power station has the valve cone itself as the only movable part, acting with its inner surface as a piston within a second cylinder space. The valve shaft is at the same time a piston rod with a stepped piston at the upper end. This piston is loaded in a cylinder at the upspace below the valve cover on one hand by a spring, on the other hand by its own medium. Two non-return valves, one of it in a bore of the valve cone, connect the first-mentioned cylinder space with the steam-loaded inlet resp. outlet side of the valve. For controlling the valve, a magnet valve is sufficient. By automatic control of the valve cone coupled with several pistons several control lines can be omitted. There are also no pressurized control lines outside the valve which could be damaged by exterior influences. (ERA) [de

  2. Mechanical versus bioprosthetic aortic valve replacement.

    Science.gov (United States)

    Head, Stuart J; Çelik, Mevlüt; Kappetein, A Pieter

    2017-07-21

    Mechanical valves used for aortic valve replacement (AVR) continue to be associated with bleeding risks because of anticoagulation therapy, while bioprosthetic valves are at risk of structural valve deterioration requiring reoperation. This risk/benefit ratio of mechanical and bioprosthetic valves has led American and European guidelines on valvular heart disease to be consistent in recommending the use of mechanical prostheses in patients younger than 60 years of age. Despite these recommendations, the use of bioprosthetic valves has significantly increased over the last decades in all age groups. A systematic review of manuscripts applying propensity-matching or multivariable analysis to compare the usage of mechanical vs. bioprosthetic valves found either similar outcomes between the two types of valves or favourable outcomes with mechanical prostheses, particularly in younger patients. The risk/benefit ratio and choice of valves will be impacted by developments in valve designs, anticoagulation therapy, reducing the required international normalized ratio, and transcatheter and minimally invasive procedures. However, there is currently no evidence to support lowering the age threshold for implanting a bioprosthesis. Physicians in the Heart Team and patients should be cautious in pursuing more bioprosthetic valve use until its benefit is clearly proven in middle-aged patients. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

  3. Acoustic valve leak detection in nuclear plants

    International Nuclear Information System (INIS)

    Dimmick, J.G.; Dickey, J.W.

    1983-01-01

    Internal valve leakage is a hidden energy loss and can cause or prolong a forced outage. Recent advances in acoustic detection of internal valve leakage have reduced piping system maintenance costs, unnecessary downtime, and energy waste. Extremely short payback periods have been reported by plants applying this technology to preventive maintenance, troubleshooting, energy conservation and outage planning. Sensors temporarily attached to the outside of valves and connected to the instruments detect ultrasonic acoustic emissions which are characteristic of internal valve leakage. Since the sensors are attached to the outside of the valves, the time and expense of dismantling the valves or removing them from the systems are eliminated. This paper describes the instrumentation and specific applications to nuclear plant valves, including independent verification of initial findings. Guidelines for potential users, including instrumentation selection, training requirements, application planning, and the choice of in-house versus contract services are discussed

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

    Energy Technology Data Exchange (ETDEWEB)

    Goretz, H G; Betting, K

    1979-01-01

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

  5. CFD simulation on flow induced vibrations in high pressure control and emergency stop turbine valve

    International Nuclear Information System (INIS)

    Lindqvist, H.

    2011-01-01

    During the refuelling outage at Unit 2 of Forsmark NPP in 2009, the high pressure turbine valves were replaced. Three month after recommissioning, an oil pipe connected to one of the actuators was broken. Measurements showed high-frequency vibration levels. The pipe break was suspected to be an effect of highly increased vibrations caused by the new valve. In order to establish the origin of the vibrations, investigations by means of CFD-simulations were made. The simulations showed that the increased vibrations most likely stems from the open cavity that the valves centre consists of. (author)

  6. Study on the Fluid Leak Diagnosis for Steam Valve in Power Plant

    International Nuclear Information System (INIS)

    Lee, Sang-Guk; Park, Jong-Hyuck; Yoo, Keun-Bae; Lee, Sun-Ki; Hong, Sung-Yull

    2006-01-01

    This study aims to estimate the applicability of acoustic emission(AE) method for the internal fluid leak from the valves. In this study, 4 inch gate steam valve leak tests were performed in order to analyze AE properties when leaks arise in valve seat. As a result of leak test for valve seat in a secondary system of power plant, we conformed that leak sound level increased in proportion to the increase of leak rate, and leak rates were compared to simulated tests. The resulting plots of leak rate versus peak frequency and AE signal level were the primary basis for determining the feasibility of quantifying leak acoustically. Previously, the large amount of data attained also allowed a favorable investigation of the effects of different leak paths, leak rates, pressure differentials through simulated test. All results of application tests are compared with results of simulated test. From the application tests, it was suggested that the AE method for diagnosis of steam leak was applicable. This paper presents quantitative measurements of fluid valve leak conditions by the analysis of AE parameter, FFT(fast fourier transform) and RMS(root mean square) level. Test apparatus were fabricated to accept a variety of leaking steam valves in order to determine what characteristics of AE signal change with leak conditions. The data for each valve were generated by varying the leak rate and recording the averaged RMS level versus time and frequency versus amplitude(FFT). Leak rates were varied by the valve differential pressure and valve size and leaking valves were observed in service. Most of the data analysis involved plotting the leak rate versus RMS level at a specific frequency to determine how well the two variables correlate in terms of accuracy, resolution, and repeatability

  7. Valve testing for UK PWR safety applications

    International Nuclear Information System (INIS)

    George, P.T.; Bryant, S.

    1989-01-01

    Extensive testing and development has been done by the Central Electricity Generating Board (CEGB) to support the design, construction and operation of Sizewell B, the UK's first PWR. A Blowdown Rig for the Assessment of Valve Operability - (BRAVO) has been constructed at the CEGB Marchwood Engineering Laboratory to reproduce PWR Pressurizer fluid conditions for the full scale testing of Pressurizer Relief System (PRS) valves. A full size tandem pair of Pilot Operated Safety Relief Valves (POSRVs) is being tested under the full range of pressurizer fluid conditions. Tests to date have produced important data on the performance of the valve in its Cold Overpressure protection mode of operation and on methods for the in-service testing of the valve. Also, a full size pressurizer safety valve has been tested under full PRS fluid conditions to develop a methodology for the pre-service testing of the Sizewell valves. Further work will be carried out to develop procedures for the in-service testing of the valve. In the Main Steam Safety Valve test program carried out at the Siemens-KWU Test Facilities, a single MSSV from three potential suppliers was tested under full secondary system conditions. The test results have been analyzed and are reflected in the CEGB's arrangements for the pre-service and in-service testing of the Sizewell MSSVs. Valves required to interrupt pipebreak flow must be qualified for this duty by testing or a combination of testing and analysis. To obtain guidance on the performance of such tests gate and globe valves have been subjected to simulated pipebreaks under PWR primary circuit conditions. In the light of problems encountered with gate valve closure under these conditions, further tests are currently being carried out on the BRAVO facility on a gate valve, in preparation for the full scale flow interruption qualification testing of the Sizewell main steam isolation valve

  8. Cosmic disposal of radioactive waste

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Y; Morisawa, S [Kyoto Univ. (Japan). Faculty of Engineering

    1975-03-01

    The technical and economical possibility and safety of the disposal of highly radioactive waste into cosmos are reviewed. The disposal of highly radioactive waste is serious problem to be solved in the near future, because it is produced in large amounts by the reprocessing of spent fuel. The promising methods proposed are (i) underground disposal, (ii) ocean disposal, (iii) cosmic disposal and (iv) extinguishing disposal. The final disposal method is not yet decided internationally. The radioactive waste contains very long life nuclides, for example transuranic elements and actinide elements. The author thinks the most perfect and safe disposal method for these very long life nuclides is the disposal into cosmos. The space vehicle carrying radioactive waste will be launched safely into outer space with recent space technology. The selection of orbit for vehicles (earth satellite or orbit around planets) or escape from solar system, selection of launching rocket type pretreatment of waste, launching weight, and the cost of cosmic disposal were investigated roughly and quantitatively. Safety problem of cosmic disposal should be examined from the reliable safety study data in the future.

  9. 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....

  10. Defense High Level Waste Disposal Container System Description Document

    International Nuclear Information System (INIS)

    2000-01-01

    The Defense High Level Waste Disposal Container System supports the confinement and isolation of waste within the Engineered Barrier System of the Monitored Geologic Repository (MGR). Disposal containers are loaded and sealed in the surface waste handling facilities, transferred to the underground through the accesses using a rail mounted transporter, and emplaced in emplacement drifts. The defense high level waste (HLW) disposal container provides long-term confinement of the commercial HLW and defense HLW (including immobilized plutonium waste forms (IPWF)) placed within disposable canisters, and withstands the loading, transfer, emplacement, and retrieval loads and environments. U.S. Department of Energy (DOE)-owned spent nuclear fuel (SNF) in disposable canisters may also be placed in a defense HLW disposal container along with commercial HLW waste forms, which is known as 'co-disposal'. The Defense High Level Waste Disposal Container System provides containment of waste for a designated period of time, and limits radionuclide release. The disposal container/waste package maintains the waste in a designated configuration, withstands maximum handling and rockfall loads, limits the individual canister temperatures after emplacement, resists corrosion in the expected handling and repository environments, and provides containment of waste in the event of an accident. Defense HLW disposal containers for HLW disposal will hold up to five HLW canisters. Defense HLW disposal containers for co-disposal will hold up to five HLW canisters arranged in a ring and one DOE SNF canister in the ring. Defense HLW disposal containers also will hold two Multi-Canister Overpacks (MCOs) and two HLW canisters in one disposal container. The disposal container will include outer and inner cylinders, outer and inner cylinder lids, and may include a canister guide. An exterior label will provide a means by which to identify the disposal container and its contents. Different materials

  11. Inspection and verification of waste packages for near surface disposal

    International Nuclear Information System (INIS)

    2000-01-01

    depending upon the individual Member State's QA/QC system for waste management. In this context, this publication is a collection of current information about various Member States' QA/QC programmes. It reviews them in terms of common approaches and technical procedures as well as applicable technologies. This TECDOC will benefit Member States, especially developing countries, that are planning, establishing or upgrading existing near surface repository systems. This publication is intended to provide technical guidance and current technical information about assuring compliance of waste packages with near surface disposal facility acceptance requirements by means of inspection and verification. It, therefore, discusses concepts of waste package inspection and verification, waste acceptance requirements, establishment of a waste package QA/QC programme, technical activities, inspection and verification procedures, and waste generator/disposal facility operator interface issues

  12. Application of ceramics to the sliding seat of valve bridge; Valve bridge yodobu eno ceramics tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, T; Ono, T [Mitsubishi Motors Corp., Tokyo (Japan)

    1997-10-01

    For use in the valve train, using an OHV (over head valve) configuration. of a 4 valve diesel engine for trucks and buses; we developed a valve bridge, a component of a valve train, with a ceramic head that is made of silicon nitride(Si3N4) in contact with a rocker arm in order to reduce cost and improve wear resistance for further diesel engine emissions regulations. In order to evaluate the effect of this valve bridge, RIG tests and durability tests on actual engines were carried out. 7 figs., 2 tabs.

  13. Experience in procurement and processing of heart valves at the Northwest Tissue Center

    International Nuclear Information System (INIS)

    Strong, M.; O'Neal, P.D.; Gage, H.N.; Moogk, M.

    1999-01-01

    The Northwest Tissue Center established a human heart valve program in 199 1. It is one of four non-profit tissue banks and one for-profit program that recover and process heart valves in the United States. During the eight years in which the Northwest Tissue Center has been involved in heart valve banking, there have been a total of 673 hearts procured for processing. The age of the donors ranged from <1 to 44 years with a mean of 26.2 years, 66% werw male,and 6.5% of the hearts procered were discarded due to a variety of medical and criteria reason. The primary reasons for differal were questions of possible cancer and questions of high risk behavior/social history. Of the 1,264 cardiovascular tissues processed, 6% were lost because of donor history, 17% were lost because of microbiology results, and 5% were lost because of donor serology . There were total a total of 190 aortic valves and 48 pulmonic conduits transplanted over this time period. The mean age of the recipients was 23.4 with a median or 23 years; 102 of the recipients were less than one year of age. Males comprised 62% of the recipients. Since 1993, there has been a clear shift towards more use of pulmonic valves over aortic valves as a results of the acceptance of the Ross procedure. Early in the program, reports were received from surgeons that some heart valves appeared to have cracks in the conduits. Experimentations in the laboratory led to the discovery that thawing too rapidly would result in cracking of these materials. Packaging was designed to reduce the rate of thawing and this has resolved the problem with cracking. The heart valve program at the Northwest Tissue Center has been very successful in providing the necessary valves for patients in the Northwest Region of the United States

  14. Late thrombosis of a mitral bioprosthetic valve with associated massive left atrial thrombus

    Directory of Open Access Journals (Sweden)

    Preetham R Muskula

    2017-04-01

    Full Text Available An 84-year-old man presented 5 years after bioprosthetic mitral valve replacement with three months of worsening dyspnea on exertion. A new mitral stenosis murmur was noted on physical examination, and an electrocardiogram revealed newly recognized atrial fibrillation. Severe mitral stenosis (mean gradient = 13 mmHg was confirmed by transthoracic echocardiography. Transesophageal echocardiography revealed markedly thickened mitral bioprosthetic leaflets with limited mobility, and a massive left atrial thrombus (>4 cm in diameter (Fig. 1A, B, C, D and Videos 1, 2, 3 and 4. Intravenous heparin was initiated, and 5 days later, he was taken to the operating room for planned redo mitral valve replacement and left atrial thrombus extraction. Intraoperative transesophageal echocardiography revealed near-complete resolution of the bioprosthetic leaflet thickening, and a mean mitral gradient of only 3 mmHg (Fig. 2A, B, C and Videos 5, 6 and 7. The patient underwent resection of the massive left atrial thrombus (Fig. 2D but did not require redo mitral valve replacement. He was initiated on heparin (and transitioned to warfarin early in the post-operative period, with complete resolution of dyspnea on exertion at 3-month follow-up. Bioprosthetic valve thrombosis is increasingly recognized as a cause of early prosthetic valve dysfunction (1, 2. This case illustrates that bioprosthetic valve thrombosis may occur years after valve replacement; therefore, any deterioration in a patient’s clinical status (new-onset dyspnea, heart failure or atrial fibrillation warrants a thorough evaluation of the bioprosthetic valve with transesophageal echocardiography. In this case, initiation of anticoagulation obviated the need for redo mitral valve replacement.

  15. Controllable picoliter pipetting using hydrophobic microfluidic valves

    Science.gov (United States)

    Zhang, M.; Huang, J.; Qian, X.; Mi, S.; Wang, X.

    2017-06-01

    A picoliter pipetting technique using the microfluidic method is presented. Utilizing the hydrophobic self-assembled monolayer films patterned in microchannels as pressure-controlled valves, a small volume of liquid can be separated by a designed channel trap and then ejected from the channel end at a higher pressure. The liquid trap section is composed of a T-shaped channel junction and a hydrophobic patch. The liquid volume can be precisely controlled by varying the distance of the hydrophobic patch from the T-junction. By this means, liquid less than 100 pl can be separated and pipetted. The developed device is potentially useful for sample dispensing in biological, medical, and chemical applications.

  16. Tests for the dynamic behavior of insulation valve screws

    International Nuclear Information System (INIS)

    Tulke, K.D.; Stoppler, W.; Stern, G.

    1994-01-01

    Thermal tensile tests were performed at a temperature of 270 C, with two new original insulation valve conical screws M30-Tx92,5 mm (material: 21 CrMo V 5 7)and two prestrained ones during the event on 27.12.92. In order to assure the results obtained with regard to the dynamic load on the insulation valve during ''quick opening'', in addition tensile impact tests were performed at 270 C with six original insulation valve conical screws. Impact velocity reached 13,5 m/s at four screws and 6 m/s at two screws. Test conditions regarding collision damping and mass distribution were adapted, by means of parameter studies, to the situation of the insulation valve. During thermal tensile tests, strength and deformation values, such as stress at flow start, tensile strength, fracture prolongation and strain, necking at fracture as well as energy absorption up to maximum force and up to rupture, were determined. During tensile impact tests, deformation values, such as elongation, strain and necking, and energy absorption by the screw, were determined. (orig.) [de

  17. Performance of balanced bellows safety relief valves

    International Nuclear Information System (INIS)

    Lai, Y.S.

    1992-01-01

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

  18. 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.

  19. Simple Check Valves for Microfluidic Devices

    Science.gov (United States)

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

    2010-01-01

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

  20. Nuclear waste disposal site

    International Nuclear Information System (INIS)

    Mallory, C.W.; Watts, R.E.; Sanner, W.S. Jr.; Paladino, J.B.; Lilley, A.W.; Winston, S.J.; Stricklin, B.C.; Razor, J.E.

    1988-01-01

    This patent describes a disposal site for the disposal of toxic or radioactive waste, comprising: (a) a trench in the earth having a substantially flat bottom lined with a layer of solid, fluent, coarse, granular material having a high hydraulic conductivity for obstructing any capillary-type flow of ground water to the interior of the trench; (b) a non-rigid, radiation-blocking cap formed from a first layer of alluvium, a second layer of solid, fluent, coarse, granular material having a high hydraulic conductivity for blocking any capillary-type flow of water between the layer of alluvium and the rest of the cap, a layer of water-shedding silt for directing surface water away from the trench, and a layer of rip-rap over the silt layer for protecting the silt layer from erosion and for providing a radiation barrier; (c) a solidly-packed array of abutting modules of uniform size and shape disposed in the trench and under the cap for both encapsulating the wastes from water and for structurally supporting the cap, wherein each module in the array is slidable movable in the vertical direction in order to allow the array of modules to flexibly conform to variations in the shape of the flat trench bottom caused by seismic disturbances and to facilitate the recoverability of the modules; (d) a layer of solid, fluent, coarse, granular materials having a high hydraulic conductivity in the space between the side of the modules and the walls of the trench for obstructing any capillary-type flow of ground water to the interior of the trench; and (e) a drain and wherein the layer of silt is sloped to direct surface water flowing over the cap into the drain

  1. Radioactive waste disposal

    International Nuclear Information System (INIS)

    Petit, J.C.

    1998-04-01

    A deep gap, reflecting a persisting fear, separates the viewpoints of the experts and that of the public on the issue of the disposal of nuclear WASTES. The history of this field is that of the proliferation with time of spokesmen who pretend to speak in the name of the both humans and non humans involved. Three periods can be distinguished: 1940-1970, an era of contestation and confusion when the experts alone represents the interest of all; 1970-1990, an era of contestation and confusion when spokespersons multiply themselves, generating the controversy and the slowing down of most technological projects; 1990-, an era of negotiation, when viewpoints, both technical and non technical, tend to get closer and, let us be optimistic, leading to the overcome of the crisis. We show that, despite major differences, the options and concepts developed by the different actors are base on two categories of resources, namely Nature and Society, and that the consensus is built up through their 'hydridation'. we show in this part that the perception of nuclear power and, in particular of the underground disposal of nuclear wastes, involves a very deep psychological substrate. Trying to change mentalities in the domain by purely scientific and technical arguments is thus in vain. The practically instinctive fear of radioactivity, far from being due only to lack of information (and education), as often postulated by scientists and engineers, is rooted in archetypical structures. These were, without doubt, reactivated in the 40 s by the traumatizing experience of the atomic bomb. In addition, anthropological-linked considerations allow us to conclude that he underground disposal of wastes is seen as a 'rape' and soiling of Mother Earth. This contributes to explaining, beyond any rationality, the refusal of this technical option by some persons. However, it would naturally be simplistic and counter-productive to limit all controversy in this domain to these psychological aspects

  2. Municipal sludge disposal economics

    Energy Technology Data Exchange (ETDEWEB)

    Jones, J L [SRI International, Menlo Park, CA; Bomberger, Jr, D C; Lewis, F M

    1977-10-01

    Costs for disposal of sludges from a municipal wastewater treatment plant normally represents greater than or equal to 25% of the total plant operating cost. The following 5 sludge handling options are considered: chemical conditioning followed by vacuum filtration, and incineration; high-pressure wet-air oxidation and vacuum filtration or filter press prior to incineration; thermal conditioning, vacuum filtraton, and incineration; high-pressure wet-air oxidation and vacuum filtration, with ash to landfill; aerobic or anaerobic digestion, followed by chemical conditioning, vacuum filtration, and disposal on land; and chemical conditioning, followed by a filter press, flash dryer, and sale as fertilizer. The 1st 2 options result in the ultimate disposal of small amounts of ash in a landfill; the digestion options require a significant landfill; the fertilizer option requires a successful marketing and sales effort. To compare the economies of scale for the options, analyses were performed for 3 plant capacities - 10, 100, and 500 mgd; as plant size increases, the economies of scale for incineration system are quite favorable. The anaerobic digestion system has a poorer capital cost-scaling factor. The incinerator options which start with chemical conditioning consume much less electrical power at all treatment plant sizes; incinerator after thermal conditioning uses more electricity but less fuel. Digestion requires no direct external fossil fuel input. The relative use of fuel is constant at all plant sizes for other options. The incinerator options can produce a significant amount of steam which may be used. The anaerobic digestion process can be a significant net producer of fuel gas.

  3. Underground disposal of radioactive wastes

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1979-08-15

    Disposal of low- and intermediate-level radioactive wastes by shallow land burial, emplacement in suitable abandoned mines, or by deep well injection and hydraulic fracturing has been practised in various countries for many years. In recent years considerable efforts have been devoted in most countries that have nuclear power programmes to developing and evaluating appropriate disposal systems for high-level and transuranium-bearing waste, and to studying the potential for establishing repositories in geological formations underlaying their territories. The symposium, organized jointly by the IAEA and OECD's Nuclear Energy Agency in cooperation with the Geological Survey of Finland, provided an authoritative account of the status of underground disposal programmes throughout the world in 1979. It was evidence of the experience that has been gained and the comprehensive investigations that have been performed to study various options for the underground disposal of radioactive waste since the last IAEA/NEA symposium on this topic (Disposal of Radioactive Waste into the Ground) was held in 1967 in Vienna. The 10 sessions covered the following topics: National programme and general studies, Disposal of solid waste at shallow depth and in rock caverns, underground disposal of liquid waste by deep well injection and hydraulic fracturing, Disposal in salt formations, Disposal in crystalline rocks and argillaceous sediments, Thermal aspects of disposal in deep geological formations, Radionuclide migration studies, Safety assessment and regulatory aspects.

  4. Radioactive waste material disposal

    Science.gov (United States)

    Forsberg, Charles W.; Beahm, Edward C.; Parker, George W.

    1995-01-01

    The invention is a process for direct conversion of solid radioactive waste, particularly spent nuclear fuel and its cladding, if any, into a solidified waste glass. A sacrificial metal oxide, dissolved in a glass bath, is used to oxidize elemental metal and any carbon values present in the waste as they are fed to the bath. Two different modes of operation are possible, depending on the sacrificial metal oxide employed. In the first mode, a regenerable sacrificial oxide, e.g., PbO, is employed, while the second mode features use of disposable oxides such as ferric oxide.

  5. Disposal - practical problems

    International Nuclear Information System (INIS)

    Hycnar, J.; Pinko, L.

    1995-01-01

    Most Polish power plants have stockyards for storage of fly ash and slag. This paper describes the: methods of fly ash and slag storage used, methods of conveying the waste to the stockpiles (by railway cars, trucks, belt conveyors or hydraulically); construction of wet stockyards and dry stockyards and comparison of the ash dumped, development of methods of ash disposal in mine workings; composition and properties of fly ash and slag from hard coal; and the effects of ash storage yards on the environment (by leaching of trace elements, dust, effect on soils, and noise of machinery). 16 refs., 3 figs., 6 tabs

  6. Nuclear fuel waste disposal

    International Nuclear Information System (INIS)

    1982-01-01

    This film for a general audience deals with nuclear fuel waste management in Canada, where research is concentrating on land based geologic disposal of wastes rather than on reprocessing of fuel. The waste management programme is based on cooperation of the AECL, various universities and Ontario Hydro. Findings of research institutes in other countries are taken into account as well. The long-term effects of buried radioactive wastes on humans (ground water, food chain etc.) are carefully studied with the help of computer models. Animated sequences illustrate the behaviour of radionuclides and explain the idea of a multiple barrier system to minimize the danger of radiation hazards

  7. Waste disposal experts meet

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1959-01-15

    Problems connected with the disposal into the sea of radioactive wastes from peaceful uses of atomic energy are being examined by a panel of experts, convened by the International Atomic Energy Agency. These experts from eight different countries held a first meeting at IAEA headquarters in Vienna from 4-9 December 1958, under the chairmanship of Dr. Harry Brynielsson, Director General of the Swedish Atomic Energy Company. The countries represented are: Canada, Czechoslovakia, France, Japan, Netherlands, United Kingdom and United States. The group will meet again in 1959. (author)

  8. HLW Disposal System Development

    Energy Technology Data Exchange (ETDEWEB)

    Choi, J. W.; Choi, H. J.; Lee, J. Y. (and others)

    2007-06-15

    A KRS is suggested through design requirement analysis of the buffer and the canister which are the constituent of disposal system engineered barrier and HLW management plans are proposed. In the aspect of radionuclide retention capacity, the thickness of the buffer is determined 0.5m, the shape to be disc and ring and the dry density to be 1.6 g/cm{sup 3}. The maximum temperature of the buffer is below 100 .deg. which meets the design requirement. And bentonite blocks with 5 wt% of graphite showed more than 1.0 W/mK of thermal conductivity without the addition of sand. The result of the thermal analysis for proposed double-layered buffer shows that decrease of 7 .deg. C in maximum temperature of the buffer. For the disposal canister, the copper for the outer shell material and cast iron for the inner structure material is recommended considering the results analyzed in terms of performance of the canisters and manufacturability and the geochemical properties of deep groundwater sampled from the research area with granite, salt water intrusion, and the heavy weight of the canister. The results of safety analysis for the canister shows that the criticality for the normal case including uncertainty is the value of 0.816 which meets subcritical condition. Considering nation's 'Basic Plan for Electric Power Demand and Supply' and based on the scenario of disposing CANDU spent fuels in the first phase, the disposal system that the repository will be excavated in eight phases with the construction of the Underground Research Laboratory (URL) beginning in 2020 and commissioning in 2040 until the closure of the repository is proposed. Since there is close correlation between domestic HLW management plans and front-end/back-end fuel cycle plans causing such a great sensitivity of international environment factor, items related to assuring the non-proliferation and observing the international standard are showed to be the influential factor and acceptability

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

    International Nuclear Information System (INIS)

    Mirkhani, S.H.; Golestani, M.G.; Hosini, M.; Kazemian, A.

    1999-01-01

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

  10. Low Transvalvular Flow Rate Predicts Mortality in Patients With Low-Gradient Aortic Stenosis Following Aortic Valve Intervention.

    Science.gov (United States)

    Vamvakidou, Anastasia; Jin, Wenying; Danylenko, Oleksandr; Chahal, Navtej; Khattar, Rajdeep; Senior, Roxy

    2018-03-09

    This study aimed to assess the value of low transvalvular flow rate (FR) for the prediction of mortality compared with low stroke volume index (SVi) in patients with low-gradient (mean gradient: gradient AS who had undergone valve intervention. We retrospectively followed prospectively assessed consecutive patients with low-gradient, low aortic valve area AS who underwent aortic valve intervention between 2010 and 2014 for all-cause mortality. Of the 218 patients with mean age 75 ± 12 years, 102 (46.8%) had low stroke volume index (SVi) (gradient, low valve area aortic stenosis undergoing aortic valve intervention, low FR, not low SVi, was an independent predictor of medium-term mortality. Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  11. Organic evaporator steam valve failure

    International Nuclear Information System (INIS)

    Jacobs, R.A.

    1992-01-01

    Defense Waste Processing Facility (DWPF) Technical has requested an analysis of the capacity of the Organic Evaporator (OE) condenser (OEC) be performed to determine its capability in the case where the OE steam flow control valve fails open. Calculations of the OE boilup and the OEC heat transfer coefficient indicate the OEC will have more than enough capacity to remove the heat at maximum OE boilup. In fact, the Salt Cell Vent Condenser (SCVC) should also have sufficient capacity to handle the maximum OE boilup. Therefore, it would require simultaneous loss of OEC and/or SCVC condensing capacity for the steam valve failure to cause high benzene in the Process Vessel Vent System (PVVS)

  12. Aerococcus viridans Native Valve Endocarditis

    Directory of Open Access Journals (Sweden)

    Wenwan Zhou

    2013-01-01

    Full Text Available Aerococcus viridans is an infrequent human pathogen and few cases of infective endocarditis have been reported. A case involving a 69-year-old man with colon cancer and hemicolectomy 14 years previously, without recurrence, is reported. A diagnosis of native mitral valve endocarditis was established on the basis of clinical presentation, characteristic echocardiographic findings and pathological specimen examination after urgent valve replacement. A viridans endocarditis appears to be particularly virulent, requiring a surgical approach in four of 10 cases reported and death in one of nine. Given the aggressive nature of A viridans endocarditis and the variable time to diagnosis (a few days to seven months, prompt recognition of symptoms and echocardiography, in addition to blood cultures, should be performed when symptoms persist.

  13. Numerical simulation on flow field of nuclear safety grade 2 single-seat pneumatic diaphragm control valve

    International Nuclear Information System (INIS)

    Zhong Yun; Zhang Jige; Wang Dezhong; Shi Jianzhong

    2010-01-01

    The Computational Fluid Dynamics (CFD) method is employed to simulate numerically the steady flow and transient flow under variable openings of the nuclear safety grade 2 single-seat pneumatic diaphragm control valve, which is a sleeve valve. The steady simulations under rated condition tells that there is a large amount of vortex in the valve seat necking and around the valve cone, which leads to a much greater flow impact on the head of the valve cone and uneven pressure distribution on spool face. More consideration should be taken on the characteristics of the valve cone accordingly, when designing a valve of this kind. Then the transient flow under 100% and 40% openings is simulated numerically on the basis of steady simulations. The pulsation of the pressure magnitude at the points with large vorticity, in the valve seat necking and around the valve cone, is monitored. The main pulsation frequencies differ from the low natural frequencies of the model, which means that it is safe from leading to structural resonance. (authors)

  14. In vitro 2D PIV measurements and related aperture areas of tricuspid bioprosthetic mitral valves at the beginning of diastole.

    Science.gov (United States)

    Bazan, Ovandir; Ortiz, Jayme Pinto; Fukumasu, Newton Kiyoshi; Pacifico, Antonio Luiz; Yanagihara, Jurandir Itizo

    2016-07-04

    Besides ventricular parameters, the design and angular orientation of a prosthetic heart valve induce a specific flow field. The aim of this study was to know the inflow characteristics of a left ventricular model (LVM), investigating the behavior of tricuspid bioprosthetic mitral valves in terms of velocity profiles and related valve aperture areas at the beginning of diastole, under different conditions. 3 heart rates (HRs) were established in the LVM and each mitral bioprosthesis (27 and 31 mm diameter) was installed in 2 orientations, rotated by 180° . For each experimental setup, 2-dimensional particle image velocimetry (2D PIV) measurements and simultaneous mitral valve (MV) area detection were obtained from 50 samples. The results from the velocity profiles immediately downstream of mitral bioprostheses showed the influence of valve orientation for moderate HRs, although for a similar magnitude of mean velocity vectors. The geometries of MV open areas for each HR were similar regardless of valve orientation, except for the 27-mm valve at 90 beats per minute (bpm), and for the 31-mm valve at 60 bpm. Moreover, for each HR, similar percentages of valve open area were obtained regardless of MV nominal diameters. In conclusion, the experimental setup for the 2D PIV measurements synchronized with the MV area detection was a useful tool for knowing the inflow characteristics of the LVM.

  15. Aortic annulus eccentricity before and after transcatheter aortic valve implantation: Comparison of balloon-expandable and self-expanding prostheses

    International Nuclear Information System (INIS)

    Schuhbaeck, Annika; Weingartner, Christina; Arnold, Martin; Schmid, Jasmin; Pflederer, Tobias; Marwan, Mohamed; Rixe, Johannes; Nef, Holger; Schneider, Christian; Lell, Michael; Uder, Michael; Ensminger, Stephan; Feyrer, Richard; Weyand, Michael; Achenbach, Stephan

    2015-01-01

    Highlights: • Post-implant geometry of catheter-based aortic valve prostheses is influenced by aortic valve calcification. • Balloon-expandable prostheses are more circular as compared to self-expanding prostheses. • The impact of post-implant geometry on valve function needs to be investigated. - Abstract: Introduction: The geometry of the aortic annulus and implanted transcatheter aortic valve prosthesis might influence valve function. We investigated the influence of valve type and aortic valve calcification on post-implant geometry of catheter-based aortic valve prostheses. Methods: Eighty consecutive patients with severe aortic valve stenosis (mean age 82 ± 6 years) underwent computed tomography before and after TAVI. Aortic annulus diameters were determined. Influence of prosthesis type and degree of aortic valve calcification on post-implant eccentricity were analysed. Results: Aortic annulus eccentricity was reduced in patients after TAVI (0.21 ± 0.06 vs. 0.08 ± 0.06, p < 0.0001). Post-TAVI eccentricity was significantly lower in 65 patients following implantation of a balloon-expandable prosthesis as compared to 15 patients who received a self-expanding prosthesis (0.06 ± 0.05 vs. 0.15 ± 0.07, p < 0.0001), even though the extent of aortic valve calcification was not different. After TAVI, patients with a higher calcium amount retained a significantly higher eccentricity compared to patients with lower amounts of calcium. Conclusions: Patients undergoing TAVI with a balloon-expandable prosthesis show a more circular shape of the implanted prosthesis as compared to patients with a self-expanding prosthesis. Eccentricity of the deployed prosthesis is affected by the extent of aortic valve calcification

  16. Bistable diverter valve in microfluidics

    Czech Academy of Sciences Publication Activity Database

    Tesař, Václav; Bandulasena, H.C.H.

    2011-01-01

    Roč. 50, č. 5 (2011), s. 1225-1233 ISSN 0723-4864 R&D Projects: GA ČR GA101/07/1499; GA AV ČR IAA200760705 Institutional research plan: CEZ:AV0Z20760514 Keywords : fluidics * bistable diverter valves * pressure-driven microfluidics Subject RIV: BK - Fluid Dynamics Impact factor: 1.735, year: 2011 http://www.springerlink.com/content/x4907p1908151522/

  17. Control valve friction operational experience at Darlington NGD

    International Nuclear Information System (INIS)

    Speer, B.

    1995-01-01

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

  18. 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...

  19. Tricuspid valve repair for severe tricuspid regurgitation due to pacemaker leads.

    Science.gov (United States)

    Uehara, Kyokun; Minakata, Kenji; Watanabe, Kentaro; Sakaguchi, Hisashi; Yamazaki, Kazuhiro; Ikeda, Tadashi; Sakata, Ryuzo

    2016-07-01

    Tricuspid valve regurgitation due to pacemaker leads is a well-known complication. Although some reports have suggested that pacemaker leads should be surgically explanted, strongly adhered leads cannot always be removed. The aim of this study was to describe our tricuspid valve repair techniques with pacemaker leads left in situ. Our retrospective study investigated 6 consecutive patients who required tricuspid valve surgery for severe regurgitation induced by pacemaker leads. From the operative findings, we identified 3 patterns of tricuspid valve and pacemaker lead involvement. In 3 patients, the leads were caught in the chordae, in 2 patients, tricuspid regurgitation was caused by lead impingement on the septal leaflet, and in 3 patients, tricuspid valve leaflets had been perforated by the pacemaker leads. During surgery, all leads were left in situ after being separated from the leaflet or valvular apparatus. In addition, suture annuloplasty was performed for annular dilatation in all cases. In one patient, the lead was reaffixed to the annulus after the posterior leaflet was cut back towards the annulus, and the leaflet was then closed. There was one hospital death due to sepsis. The degree of tricuspid regurgitation was trivial in all surviving patients at discharge. During a mean follow-up of 21 months, one patient died from pneumonia 20 months after tricuspid valve repair. In patients undergoing tricuspid valve surgery due to severe tricuspid regurgitation caused by pacemaker leads, the leads can be left in situ after proper repair with annuloplasty. © The Author(s) 2016.

  20. Expression of uPA, tPA, and PAI-1 in Calcified Aortic Valves

    Directory of Open Access Journals (Sweden)

    Najlah Kochtebane

    2014-01-01

    Full Text Available Purpose. Our physiopathological assumption is that u-PA, t-PA, and PAI-1 are released by calcified aortic valves and play a role in the calcification of these valves. Methods. Sixty-five calcified aortic valves were collected from patients suffering from aortic stenosis. Each valve was incubated for 24 hours in culture medium. The supernatants were used to measure u-PA, t-PA, and PAI-1 concentrations; the valve calcification was evaluated using biphotonic absorptiometry. Results. Aortic stenosis valves expressed normal plasminogen activators concentrations and overexpressed PAI-1 (u-PA, t-PA, and PAI-1 mean concentrations were, resp., 1.69 ng/mL ± 0.80, 2.76 ng/mL ± 1.33, and 53.27 ng/mL ± 36.39. There was no correlation between u-PA and PAI-1 (r=0.3 but t-PA and PAI-1 were strongly correlated with each other (r=0.6. Overexpression of PAI-1 was proportional to the calcium content of the AS valves. Conclusions. Our results demonstrate a consistent increase of PAI-1 proportional to the calcification. The overexpression of PAI-1 may be useful as a predictive indicator in patients with aortic stenosis.

  1. A 3D velocimetry study of the flow through prosthetic heart valves

    Science.gov (United States)

    Ledesma, R.; Zenit, R.; Pulos, G.; Sanchez, E.; Juarez, A.

    2006-11-01

    Blood damage commonly appears in medical valve prothesis. It is a mayor concern for the designers and surgeons. It is well known that this damage and other complications result from the modified fluid dynamics through the replacement valve. To evaluate the performance of prosthetic heart valves, it is necessary to study the flow through them. To conduct this study , we have built a flow channel that emulates cardiac conditions and allows optical access such that a 3D-PIV velocimetry system could be used. The experiments are aimed to reconstruct the downstream structure of the flow through a mechanical and a bio-material tricuspid heart valve prothesis. Preliminary results show that the observed coherent structures can be related with haemolysis and trombosis, illnesses commonly found in valve prothesis recipients. The mean flow, the levels of strain rate and the turbulence intensity generated by the valves can also be directly related to blood damage. In general, bio-material made valves tend to reduce these complications.

  2. Conceptual design of a compact absolute valve for the ITER neutral beam injectors

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Chris [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom)], E-mail: chris.m.jones@jet.uk; Waldon, Chris; Martin, David; Watson, Mike [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Sonderegger, Kurt; Lenherr, Bruno [VAT Vakuumventile AG, CH-9469 Haag (Switzerland); Andrews, Ian; Mansbridge, Simon [VAT Vacuum Products Ltd., Edmund House, Rugby Road, Leamington Spa, Warwickshire CV32 6EL (United Kingdom)

    2009-06-15

    The reference design for the ITER neutral beam injectors incorporated a fast shutter to limit tritium migration to the injector vacuum enclosures. In 2005, a need for an 'absolute' isolation valve was identified to facilitate injector maintenance procedures and protect the system from an in-vessel ingress of coolant event (ICE). An outline concept for an all-metal seal valve was developed during 2006, in close cooperation with the Swiss valve manufacturer VAT. During the following year, it became apparent that the length of beamline available for the valve was significantly less than originally envisaged, resulting in a radical revision of the design concept. A casing length of 760 mm has been achieved by means of major changes to the casing structure, plate dimensions, pendulum mechanism and seal actuators. A concept for a seal protection system has been developed to prevent beam line contamination reaching the valve components and to protect the valve plate from surface heating by plasma radiation. The new design concept has been extensively validated by analysis, including a whole-system FE model of the valve.

  3. Comparative study of encapsulated blebs following Ahmed glaucoma valve implantation and trabeculectomy with mitomycin-C.

    Science.gov (United States)

    Bae, Kunho; Suh, Wool; Kee, Changwon

    2012-08-01

    To compare the histopathologic and morphologic findings of encapsulated blebs following Ahmed glaucoma valve implantation and primary standard trabeculectomy with mitomycin-C. We reviewed the records of patients with otherwise uncontrollable glaucoma who had undergone Ahmed glaucoma valve implantation or trabeculectomy with mitomycin-C. Five eyes that underwent Ahmed valve implantation and three eyes that underwent trabeculectomy needed surgical revision of the initial surgery due to encapsulated bleb development with total loss of function. The surgically removed encapsulated blebs were analyzed macroscopically and microscopically. Removal of the encapsulated bleb was performed at a mean follow-up time of 26.6 ± 19.4 weeks in the Ahmed valve implantation group and 12.0 ± 11.4 weeks in the trabeculectomy group. The fibrotic wall of the encapsulated blebs had an overall thickness of 2.48 ± 0.42 mm in the Ahmed valve implantation group and 1.62 ± 0.37 mm in the trabeculectomy group. Macroscopically, the coconut flesh-like smooth surface was split into two layers, and the wall of the capsule was thicker in the Ahmed valve implantation group than in the trabeculectomy group. Histopathologically, the fibrotic capsule was composed of an inner fibrodegenerative layer and an outer fibrovascular layer, and there were no histopathological differences between the two groups. The fibrotic capsule wall was thicker in the Ahmed valve group, but there were no differences in histological findings between the two groups.

  4. Characteristics of transonic moist air flows around butterfly valves with spontaneous condensation

    Directory of Open Access Journals (Sweden)

    A.B.M. Toufique Hasan

    2015-06-01

    Full Text Available Effects of spontaneous condensation of moist air on the shock wave dynamics around butterfly valves in transonic flows are investigated by experimental and numerical simulations. Two symmetric valve disk shapes namely- a flat rectangular plate and a mid-plane cross-section of a prototype butterfly valve have been studied in the present research. Results showed that in case with spontaneous condensation, the root mean square of pressure oscillation (induced by shock dynamics is reduced significantly with those without condensation for both shapes of the valves. Moreover, local aerodynamic moments were reduced in case with condensation which is considered to be beneficial in torque requirement in case of on/off applications of valves as flow control devices. However, total pressure loss was increased with spontaneous condensation in both the valves. Furthermore, the disk shape of a prototype butterfly valve showed better aerodynamic performances compared to flat rectangular plate profile in respect of total pressure loss and vortex shedding frequency in the wake region.

  5. Numerical study on cavitation inception in the rotary valve of the hydraulic power steering system

    International Nuclear Information System (INIS)

    Ryu, Gwang Nyeon; Cho, Myung Hwan; Yoo, Jung Yul; Park, Sun Hong

    2009-01-01

    The rotary valve directs the power steering oil to either side of a power piston and relieves the driver of the effort to turn the wheel, when a driver begins to operate the vehicle. It is well known that the hiss noise occurring at that moment is caused mainly by cavitation of the oil inside the rotary valve. In this paper, two types of rotary valve (round and straight type) have been analyzed numerically using three-dimensional cavitation model embedded in the commercial code, FLUENT v6.2 and the results have been compared with the measured hiss noise level in a semi-anechoic chamber. The volume of the oil vapor generated from cavitation was larger in Round type valve which has a convex shape of the sleeve grooves than in Straight type valve which has a rectangular shape of the sleeve grooves. The hiss noise level of Round type valve was higher than that of Straight type valve as well. These results mean that the hiss noise can be reduced by the change of the shape of the grooves.

  6. Numerical convergence for a sewage disposal problem

    OpenAIRE

    Alvarez-Vázquez, L.J.; Martínez, A.; Rodríguez, C.; Vázquez-Méndez, M.E.

    2001-01-01

    The management of sewage disposal and the design of wastewater treatment systems can be formulated as a constrained pointwise optimal control problem. In this paper we study the convergence of the numerical resolution for the corresponding state system by means of a characteristics Galerkin method. The main difficulty of the problem is due to the existence of Radon measures in the right-hand side of the state system. Finally, we present numerical results for a realistic problem posed in a ria...

  7. 10 CFR 61.52 - Land disposal facility operation and disposal site closure.

    Science.gov (United States)

    2010-01-01

    ... DISPOSAL OF RADIOACTIVE WASTE Technical Requirements for Land Disposal Facilities § 61.52 Land disposal... wastes by placing in disposal units which are sufficiently separated from disposal units for the other... between any buried waste and the disposal site boundary and beneath the disposed waste. The buffer zone...

  8. Borehole disposal design concept

    International Nuclear Information System (INIS)

    RANDRIAMAROLAHY, J.N.

    2007-01-01

    In Madagascar, the sealed radioactive sources are used in several socioeconomic sectors such as medicine, industry, research and agriculture. At the end of their useful lives, these radioactive sources become radioactive waste and can be still dangerous because they can cause harmful effects to the public and the environment. This work entitled 'Borehole disposal design concept' consists in putting in place a site of sure storage of the radioactive waste, in particular, sealed radioactive sources. Several technical aspects must be respected to carry out such a site like the geological, geomorphologic, hydrogeologic, geochemical, meteorological and demographic conditions. This type of storage is favorable for the developing countries because it is technologically simple and economic. The cost of construction depends on the volume of waste to store and the depth of the Borehole. The Borehole disposal concept provides a good level of safety to avoid the human intrusion. The future protection of the generations against the propagation of the radiations ionizing is then assured. [fr

  9. Research on geological disposal

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-08-15

    The aims of this research are to develop criteria for reviewing reliability and suitability of the result from Preliminary Investigations to be submitted by the implementer, and to establish a basic policy for safety review. For development of reliability and suitability criteria for reviewing the result of Preliminary Investigations, we evaluated the uncertainties and their influence from limited amount of investigations, as well as we identified important procedures during investigations and constructions of models, as follows: (1) uncertainties after limited amount of geological exploration and drilling, (2) influence of uncertainties in regional groundwater flow model, (3) uncertainties of DFN (Discrete Fracture Network) models in the fractured rock, (4) analyzed investigation methods described in implementer's report, and (5) identified important aspects in investigation which need to be reviewed and follow QA (Quality Assurance). For development of reliability and suitability criteria for reviewing the result of Detailed Investigations, we analyzed important aspects in investigation which supplies data to design and safety assessment, as well as studied the applicability of pressure interference data during excavation to verify hydrogeological model. Regarding the research for safety review, uncertainties of geologic process in long time-scale was studied. In FY2012, we started to evaluate the structural stabilities of concrete and bentonite in disposal environment. Finally, we continued to accumulate the knowledge on geological disposal into the database system. (author)

  10. Mine tailings disposal

    International Nuclear Information System (INIS)

    Gonzales, P.A.; Adams, B.J.

    1980-06-01

    The hydrologic evaluation of mine tailings disposal sites after they are abandoned is considered in relation to their potential environmental impact on a long term basis. There is a direct relation between the amounts and types of water leaving a disposal site and the severity of the potential damage to the environment. The evaluation of the relative distribution of the precipitation reaching the ground into evaporation, runoff and infiltration is obtained for a selected site and type of tailings material whose characteristics and physical properties were determined in the soils laboratory. A conceptual model of the hydrologic processes involved and the corresponding mathematical model were developed to simulate the physical system. A computer program was written to solve the set of equations forming the mathematical model, considering the physical properties of the tailings and the rainfall data selected. The results indicate that the relative distribution of the precipitation depends on the surface and upper layer of the tailings and that the position of the groundwater table is governed by the flow through the bottom of the profile considered. The slope of the surface of the mass of tailings was found to be one of the principal factors affecting the relative distribution of precipitation and, therefore, the potential pollution of the environment

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

    Science.gov (United States)

    DeWall, Kevin George [Pocatello, ID; Garcia, Humberto Enrique [Idaho Falls, ID; McKellar, Michael George [Idaho Falls, ID

    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.

  12. Design and performance characteristic analysis of servo valve-type water hydraulic poppet valve

    International Nuclear Information System (INIS)

    Park, Sung Hwan

    2009-01-01

    For water hydraulic system control, the flow or pressure control using high-speed solenoid valve controlled by PWM control method could be a good solution for prevention of internal leakage. However, since the PWM control of on-off valves cause extensive flow and pressure fluctuation, it is difficult to control the water hydraulic actuators precisely. In this study, the servo valve-type water hydraulic valve using proportional poppet as the main valve is designed and the performance characteristics of the servo valve-type water hydraulic valve are analyzed. Furthermore, it is demonstrated through experiments that a decline in control chamber pressure that follows the change of pilot flow is caused by the occurrence of cavitation around the proportional poppet, and that fundamental characteristics of the developed valve remain unaffected by the occurrence of cavitation

  13. 3D Printed Multimaterial Microfluidic Valve.

    Directory of Open Access Journals (Sweden)

    Steven J Keating

    Full Text Available 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.

  14. The radiology of prosthetic heart valves

    International Nuclear Information System (INIS)

    Steiner, R.M.; Flicker, S.

    1985-01-01

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

  15. Disposal of radioactive waste material

    International Nuclear Information System (INIS)

    Cairns, W.J.; Burton, W.R.

    1984-01-01

    A method of disposal of radioactive waste consists in disposing the waste in trenches dredged in the sea bed beneath shallow coastal waters. Advantageously selection of the sites for the trenches is governed by the ability of the trenches naturally to fill with silt after disposal. Furthermore, this natural filling can be supplemented by physical filling of the trenches with a blend of absorber for radionuclides and natural boulders. (author)

  16. North American trial results at 1 year with the Sorin Freedom SOLO pericardial aortic valve.

    Science.gov (United States)

    Heimansohn, David; Roselli, Eric E; Thourani, Vinod H; Wang, Shaohua; Voisine, Pierre; Ye, Jian; Dabir, Reza; Moon, Michael

    2016-02-01

    A North American prospective, 15-centre Food and Drug Administration (FDA) valve trial was designed to assess the safety and effectiveness of the Freedom SOLO stentless pericardial aortic valve in the treatment of surgical aortic valve disease. Beginning in 2010, 251 patients (mean: 74.7 ± 7.5 years), were recruited in the Freedom SOLO aortic valve trial. One hundred eighty-nine patients have been followed for at least 1 year and are the basis for this review. Preoperatively, 54% of patients had NYHA functional class III or IV symptoms, and the majority of patients had a normal ejection fraction (EF) (median EF = 61%). Concomitant procedures were performed in 61.9% of patients, with coronary artery bypass grafting (CABG) (48.7%) being the most common followed by a MAZE procedure (13.7%). Reoperations were performed in 8.5% of patients in the study. The entire cohort of 251 patients enrolled had 7 deaths prior to 30 days, 2 of which were valve-related (aspiration pneumonia and sudden death) and 5 were not valve-related. There were 11 deaths after 30 days, 1 valve-related (unknown cardiac death) and 10 not valve-related. Five valves were explanted, 3 early (endocarditis, acute insufficiency and possible root dissection) and 2 late (endocarditis). Thirty-day adverse events include arrhythmias requiring permanent pacemaker (4.2%), thromboembolic events (3.7%) and thrombocytopenia (7.4%). One-year follow-up of all 189 patients demonstrated mean gradients for valve sizes 19, 21, 23, 25 and 27 mm of 11.7, 7.8, 6.3, 4.6 and 5.0 mmHg, respectively. Effective orifice areas for the same valve sizes were 1.2, 1.3, 1.6, 1.8 and 1.9 cm(2), respectively. Ninety-six percent of patients (181/189) were in NYHA class I or II at the 1-year follow-up. The Freedom SOLO stentless pericardial aortic valve demonstrated excellent haemodynamics and a good safety profile out to the 1 year of follow-up. © The Author 2015. Published by Oxford University Press on behalf of the European

  17. Clinical Implication of Aortic Wall Biopsy in Aortic Valve Disease with Bicuspid Valve Pathology

    Directory of Open Access Journals (Sweden)

    Yong Han Kim

    2016-12-01

    Full Text Available Background: Although unique aortic pathology related to bicuspid aortic valve (BAV has been previously reported, clinical implications of BAV to aortopathy risk have yet to be investigated. We looked for potential differences in matrix protein expressions in the aortic wall in BAV patients. Methods: Aorta specimens were obtained from 31 patients: BAV group (n=27, tricuspid aortic valve (TAV group (n=4. The BAV group was categorized into three subgroups: left coronary sinus-right coronary sinus (R+L group; n=13, 42%, right coronary sinus-non-coronary sinus (R+N group; n=8, 26%, and anteroposterior (AP group; n=6, 19%. We analyzed the expression of endothelial nitric oxide synthase (eNOS, matrix metalloproteinase (MMP-9, and tissue inhibitor of matrix metalloproteinase (TIMP-2. Results: Based on the mean value of the control group, BAV group showed decreased expression of eNOS in 72.7% of patients, increased MMP-9 in 82.3%, and decreased TIMP in 79.2%. There was a higher tendency for aortopathy in the BAV group: eNOS (BAV:TAV= 53%±7%:57%±11%, MMP-9 (BAV:TAV=48%±10%:38%±1%. The AP group showed lower expression of eNOS than the fusion (R+L, R+N group did; 48%±5% vs. 55%±7% (p=0.081. Conclusion: Not all patients with BAV had expression of aortopathy; however, for patients who had a suspicious form of bicuspid valve, aortic wall biopsy could be valuable to signify the presence of aortopathy.

  18. Trans-apical aortic valve implantation in a patient with stentless valve degeneration.

    Science.gov (United States)

    Kapetanakis, Emmanouil I; MacCarthy, Philip; Monaghan, Mark; Wendler, Olaf

    2011-06-01

    Trans-apical valve-in-valve trans-catheter aortic valve implantation (TAVI) has successfully been performed in selected, high-risk patients, who suffered prosthetic degeneration after aortic valve replacement using stented xenografts. We report the case of a 79-year-old male patient who underwent one of the first successful TAVIs in a failing stentless bioprosthesis. Copyright © 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

  19. Optimal valve location in long oil pipelines

    OpenAIRE

    Grigoriev, A.; Grigorieva, N.V.

    2007-01-01

    We address the valve location problem, one of the basic problems in design of long oil pipelines. Whenever a pipeline is depressurized, the shutoff valves block the oil flow and seal the damaged part of the pipeline. Thus, the quantity of oil possibly contaminating the area around the pipeline is determined by the volume of the damaged section of the pipeline between two consecutive valves. Then, ecologic damage can be quantified by the amount of leaked oil and the environmental characteristi...

  20. Bistable (latching) solenoid actuated propellant isolation valve

    Science.gov (United States)

    Wichmann, H.; Deboi, H. H.

    1979-01-01

    The design, fabrication, assembly and test of a development configuration bistable (latching) solenoid actuated propellant isolation valve suitable for the control hydrazine and liquid fluorine to an 800 pound thrust rocket engine is described. The valve features a balanced poppet, utilizing metal bellows, a hard poppet/seat interface and a flexure support system for the internal moving components. This support system eliminates sliding surfaces, thereby rendering the valve free of self generated particles.

  1. Improved valve and dash-pot assembly

    Science.gov (United States)

    Chang, S.C.

    1985-04-23

    A dash-pot valve comprises a cylinder submerged in the fluid of a housing and have a piston attached to a plunger projecting into the path of closing movement of a pivotal valve member. A vortex chamber in said cylinder is provided with targentially directed inlets to generate vortex flow upon retraction of said plunger and effect increasing resistance against said piston to progressively retard the closing rate of said valve member toward its seat.

  2. Valve and dash-pot assembly

    Science.gov (United States)

    Chang, Shih-Chih

    1986-01-01

    A dash-pot valve comprising a cylinder submerged in the fluid of a housing and having a piston attached to a plunger projecting into the path of closing movement of a pivotal valve member. A vortex chamber in said cylinder is provided with tangentially directed inlets to generate vortex flow upon retraction of said plunger and effect increasing resistance against said piston to progressively retard the closing rate of said valve member toward its seat.

  3. Report on radioactive waste disposal

    International Nuclear Information System (INIS)

    1993-01-01

    The safe management of radioactive wastes constitutes an essential part of the IAEA programme. A large number of reports and conference proceedings covering various aspects of the subject have been issued. The Technical Review Committee on Underground Disposal (February 1988) recommended that the Secretariat issue a report on the state of the art of underground disposal of radioactive wastes. The Committee recommended the need for a report that provided an overview of the present knowledge in the field. This report covers the basic principles associated with the state of the art of near surface and deep geological radioactive waste disposal, including examples of prudent practice, and basic information on performance assessment methods. It does not include a comprehensive description of the waste management programmes in different countries nor provide a textbook on waste disposal. Such books are available elsewhere. Reviewing all the concepts and practices of safe radioactive waste disposal in a document of reasonable size is not possible; therefore, the scope of this report has been limited to cover essential parts of the subject. Exotic disposal techniques and techniques for disposing of uranium mill tailings are not covered, and only brief coverage is provided for disposal at sea and in the sea-bed. The present report provides a list of references to more specialized reports on disposal published by the IAEA as well as by other bodies, which may be consulted if additional information is sought. 108 refs, 22 figs, 2 tabs

  4. The Meaning of Meaning, Etc.

    Science.gov (United States)

    Nilsen, Don L. F.

    This paper attempts to dispel a number of misconceptions about the nature of meaning, namely that: (1) synonyms are words that have the same meanings, (2) antonyms are words that have opposite meanings, (3) homonyms are words that sound the same but have different spellings and meanings, (4) converses are antonyms rather than synonyms, (5)…

  5. Outcomes of Aortic Valve-Sparing Operations in Marfan Syndrome.

    Science.gov (United States)

    David, Tirone E; David, Carolyn M; Manlhiot, Cedric; Colman, Jack; Crean, Andrew M; Bradley, Timothy

    2015-09-29

    In many cardiac units, aortic valve-sparing operations have become the preferred surgical procedure to treat aortic root aneurysm in patients with Marfan syndrome, based on relatively short-term outcomes. This study examined the long-term outcomes of aortic valve-sparing operations in patients with Marfan syndrome. All patients with Marfan syndrome operated on for aortic root aneurysm from 1988 through 2012 were followed prospectively for a median of 10 years. Follow-up was 100% complete. Time-to-event analyses were calculated using the Kaplan-Meier method with log-rank test for comparisons. A total of 146 patients with Marfan syndrome had aortic valve-sparing operations. Reimplantation of the aortic valve was performed in 121 and remodeling of the aortic root was performed in 25 patients. Mean age was 35.7 ± 11.4 years and two-thirds were men. Nine patients had acute, 2 had chronic type A, and 3 had chronic type B aortic dissections before surgery. There were 1 operative and 6 late deaths, 5 caused by complications of dissections. Mortality rate at 15 years was 6.8 ± 2.9%, higher than the general population matched for age and sex. Five patients required reoperation on the aortic valve: 2 for endocarditis and 3 for aortic insufficiency. Three patients developed severe, 4 moderate, and 3 mild-to-moderate aortic insufficiency. Rate of aortic insufficiency at 15 years was 7.9 ± 3.3%, lower after reimplantation than remodeling. Nine patients developed new distal aortic dissections during follow-up. Rate of dissection at 15 years was 16.5 ± 3.4%. Aortic valve-sparing operations in patients with Marfan syndrome were associated with low rates of valve-related complications in long-term follow-up. Residual and new aortic dissections were the leading cause of death. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  6. Double-reed exhaust valve engine

    Science.gov (United States)

    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.

  7. Fast Flux Test Facility primary sodium valves

    International Nuclear Information System (INIS)

    Rabe, G.B.; Ezra, B.C.

    1977-01-01

    The design and development of the valves used in the primary sodium coolant loop of the Fast Flux Test Facility is described. One tilting-disk check valve is used in the cold leg of the coolant loop. It is designed to limit flow reversal in the loop while maintaining a low pressure drop during forward flow. Two isolation valves are used in each coolant loop--one in the cold leg and one in the hot leg. They are of the motor-operated swinging-gate type. The design, analysis, and testing programs undertaken to develop and qualify these valves are described

  8. Advantages of butterfly valves for power plants

    International Nuclear Information System (INIS)

    Lapadat, J.T.

    1977-01-01

    Butterfly valves are increasingly used in nuclear power plants. They are used in CANDU reactors for class 2 and 3 service, to provide emergency and tight shutoff valves for all inlets and outlets of heat exchangers and all calandria penetrations. Guidelines for meeting nuclear power plant valve specifications are set out in ASME Section 3, Nuclear Power Plant Components. Some details of materials of construction, type of actuator, etc., for various classes of nuclear service are tabulated in the present article. The 'fishtail' butterfly valve is an improved design with reduced drag, as is illustrated and explained. (N.D.H.)

  9. Safety valve opening and closing operation monitor

    International Nuclear Information System (INIS)

    Kodama, Kunio; Takeshima, Ikuo; Takahashi, Kiyokazu.

    1981-01-01

    Purpose: To enable the detection of the closing of a safety valve when the internal pressure in a BWR type reactor is a value which will close the safety valve, by inputting signals from a pressure detecting device mounted directly at a reactor vessel and a safety valve discharge pressure detecting device to an AND logic circuit. Constitution: A safety valve monitor is formed of a pressure switch mounted at a reactor pressure vessel, a pressure switch mounted at the exhaust pipe of the escape safety valve and a logic circuit and the lide. When the input pressure of the safety valve is raised so that the valve and the pressure switch mounted at the exhaust pipe are operated, an alarm is indicated, and the operation of the pressure switch mounted at a pressure vessel is eliminated. If the safety valve is not reclosed when the vessel pressure is decreased lower than the pressure at which it is to be reclosed after the safety valve is operated, an alarm is generated by the logic circuit since both the pressure switches are operated. (Sekiya, K.)

  10. Outcome of pregnancy in women after pulmonary autograft valve replacement for congenital aortic valve disease

    NARCIS (Netherlands)

    Yap, Sing-Chien; Drenthen, Willem; Pieper, Petronella G.; Moons, Philip; Mulder, Barbara J. M.; Klieverik, Loes M.; Vliegen, Hubert W.; van Dijk, Arie P. J.; Meijboom, Folkert J.; Roos-Hesselink, Jolien W.

    Background and aim of the study: The pulmonary autograft has been recommended as the valve of choice for aortic valve replacement (AVR) in young women contemplating pregnancy. However, current information on maternal and perinatal outcome of pregnancy in women with pulmonary autograft valve

  11. Outcome of pregnancy in women after pulmonary autograft valve replacement for congenital aortic valve disease

    NARCIS (Netherlands)

    Yap, Sing-Chien; Drenthen, Willem; Pieper, Petronella G.; Moons, Philip; Mulder, Barbara J. M.; Klieverik, Loes M.; Vliegen, Hubert W.; van Dijk, Arie P. J.; Meijboom, Folkert J.; Roos-Hesselink, Jolien W.

    2007-01-01

    Background and aim of the study: The pulmonary autograft has been recommended as the valve of choice for aortic valve replacement (AVR) in young women contemplating pregnancy. However, current information on maternal and perinatal outcome of pregnancy in women with pulmonary autograft valve

  12. Outcome of pregnancy in women after pulmonary autograft valve replacement for congenital aortic valve disease.

    NARCIS (Netherlands)

    Yap, S.C.; Drenthen, W.; Pieper, P.G.; Moons, P.; Mulder, B.J.M.; Klieverik, L.M.; Vliegen, H.W.; Dijk, A.P.J. van; Meijboom, F.J.; Roos-Hesselink, J.W.

    2007-01-01

    BACKGROUND AND AIM OF THE STUDY: The pulmonary autograft has been recommended as the valve of choice for aortic valve replacement (AVR) in young women contemplating pregnancy. However, current information on maternal and perinatal outcome of pregnancy in women with pulmonary autograft valve

  13. 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.

  14. Small valve area index: its influence on early mortality after mitral valve replacement

    NARCIS (Netherlands)

    Yazdanbakhsh, A. P.; van den Brink, R. B.; Dekker, Egbert; de Mol, B. A.

    2000-01-01

    OBJECTIVE: To test the hypothesis that mitral valve prosthesis-patient mismatch increases postoperative mortality. METHODS AND RESULTS: The effect of mitral valve prosthesis-patient mismatch on survival in a cohort of consecutive patients after mitral valve replacement with a mechanical prosthesis

  15. Impact of bicuspid aortic valve on complications and death in infective endocarditis of native aortic valves.

    Science.gov (United States)

    Kahveci, Gokhan; Bayrak, Fatih; Pala, Selcuk; Mutlu, Bulent

    2009-01-01

    We retrospectively investigated the impact of bicuspid aortic valve on the prognosis of patients who had definite infective endocarditis of the native aortic valve.Of 51 patients, a bicuspid aortic valve was present in 22 (43%); the other 29 had tricuspid aortic valves. On average, the patients who had bicuspid valves were younger than those who had tricuspid valves. Patients with a tricuspid valve had larger left atrial diameters and were more likely to have severe mitral regurgitation.Periannular complications, which we detected in 19 patients (37%), were much more common in the patients who had a bicuspid valve (64% vs 17%, P = 0.001). The presence of a bicuspid valve was the only significant independent predictor of periannular complications. The in-hospital mortality rate in the bicuspid group was lower than that in the tricuspid group; however, this figure did not reach statistical significance (9% vs 24%, P = 0.15). In multivariate analysis, left atrial diameter was the only independent predictor associated with an increased risk of death (hazard ratio, 2.19; 95% confidence interval, 1.1-4.5; P = 0.031).In our study, patients with infective endocarditis in a bicuspid aortic valve were younger and had a higher incidence of periannular complications. Although a worse prognosis has been reported previously, we found that infective endocarditis in a native bicuspid aortic valve is not likely to increase the risk of death in comparison with infective endocarditis in native tricuspid aortic valves.

  16. Means for preventing radioactive fluid leaking

    International Nuclear Information System (INIS)

    Akatsu, Jun-ichi.

    1975-01-01

    Object: To permit prevention of leakage of radioactive fluid from line and valve leak sections while also recovering the liquid by producing a vacuum state in a leak-off line by means of a water ejector. Structure: A portion of the water from a condenser is forced by a condensed water pump through a water ejector tank to a recovery tank while controlling an orifice and valve, whereby a vacuum state is produced in the leak-off line to withdraw the leakage fluid. (Kamimura, M.)

  17. Method of effecting fast turbine valving for improvement of power system stability

    International Nuclear Information System (INIS)

    Park, R.H.

    1981-01-01

    As a improved way of effecting fast valving of turbines of power system steam-electric generating units for the purpose of improving the stability of power transmission over transmission circuits to which their generators make connection, when stability is threatened by line faults and certain other stability endangering events, the heretofore employed and/or advocated practice of automatically closing intercept valves at fastest available closing speed in response to a fast valving signal, and thereafter automatically fully reopening them in a matter of seconds, is modified by providing to reopen the valves only partially to and thereafter retain them at a preset partially open position. For best results the process of what can be termed sustained partial reopening is so effected as to result in its completion within a fraction of a second following the peak of the first forward swing of the generator rotor. Control valves may be either held open, or automatically fully or partly closed and thereafter fully opened in a preprogrammed manner, or automatically moved to and thereafter held in a partly closed position, by means of a preprogrammed process of repositioning in which the valves may optionally be first fully or partly closed and thereafter partly reopened. Avoidance of discharge of steam through high pressure safety valves can be had with use of suitably controlled power operated valves that discharge steam to the condenser or to atmosphere. Where there is an intermediate pressure turbine that is supplied with superheated steam, use of sustained partial control valve closure, if employed, is supplemented by provision for reduction of rate of heat release within the steam generator in order to protect the reheater from overheating. As a way to restrict increase of reheat pressure of fossil fuel installations, and to minimize increase in the msr (Moisture separator-reheater) pressure of nuclear units, provision is optionally made of normally closed by-pass v

  18. The development of fusion sensor techniques for condition monitoring of a check valve

    International Nuclear Information System (INIS)

    Seong, S.H.; Kim, J.S.; Hur, S.; Kim, J.T.; Park, W.M.; Cha, D.B.

    2004-01-01

    The failures of check valves are one of the most important problems in nuclear power plants because the reverse flows through the failed check valve impact on the healthy hydraulic loop. The present test method of finding out the mechanical failure of a check valve is very risky in the radiated environments during normal operation. In addition, the detection of failures in the overhaul period is very costly and tedious because many check valves are used in the plants and manual disassembly work is required. We have suggested the fusion sensor technology for detecting the failures of check valves through measuring and analyzing the backward leakage flow and mechanical vibration without disassembling the check valve. The fusion sensor means that more than two sensors are used in order to identify and analyze the changes of the frequency response between the failed check valve and healthy check valve. We use the accelerometer and acoustic emission sensor as an alternative to the fusion sensor methodology. We have found that the acoustic emission sensor would be capable of directly detecting a high frequency acoustic wave generated from backward leakage flow itself at a low pressure and temperature. The accelerometer for detecting the mechanical vibration induced from leakage flows would, also, be useful at a high pressure and temperature from the previous studies. The effectiveness of this system is that it is possible for predictive maintenance and information of the problem valve will be captured and it reduces the radiation exposure for the maintenance personnel during power operation as well as the maintenance period. (orig.)

  19. Incidence of cerebrovascular accidents in patients undergoing minimally invasive valve surgery.

    Science.gov (United States)

    LaPietra, Angelo; Santana, Orlando; Mihos, Christos G; DeBeer, Steven; Rosen, Gerald P; Lamas, Gervasio A; Lamelas, Joseph

    2014-07-01

    Minimally invasive valve surgery has been associated with increased cerebrovascular complications. Our objective was to evaluate the incidence of cerebrovascular accidents in patients undergoing minimally invasive valve surgery. We retrospectively reviewed all the minimally invasive valve surgery performed at our institution from January 2009 to June 2012. The operative times, lengths of stay, postoperative complications, and mortality were analyzed. A total of 1501 consecutive patients were identified. The mean age was 73 ± 13 years, and 808 patients (54%) were male. Of the 1501 patients, 206 (13.7%) had a history of a cerebrovascular accident, and 225 (15%) had undergone previous heart surgery. The procedures performed were 617 isolated aortic valve replacements (41.1%), 658 isolated mitral valve operations (43.8%), 6 tricuspid valve repairs (0.4%), 216 double valve surgery (14.4%), and 4 triple valve surgery (0.3%). Femoral cannulation was used in 1359 patients (90.5%) and central cannulation in 142 (9.5%). In 1392 patients (92.7%), the aorta was clamped, and in 109 (7.3%), the surgery was performed with the heart fibrillating. The median aortic crossclamp and cardiopulmonary bypass times were 86 minutes (interquartile range [IQR], 70-107) minutes and 116 minutes (IQR, 96-143), respectively. The median intensive care unit length of stay was 47 hours (IQR, 29-74), and the median postoperative hospital length of stay was 7 days (IQR, 5-10). A total of 23 cerebrovascular accidents (1.53%) and 38 deaths (2.53%) had occurred at 30 days postoperatively. Minimally invasive valve surgery was associated with an acceptable stroke rate, regardless of the cannulation technique. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  20. Dysfunction of mechanical heart valve prosthesis: experience with surgical management in 48 patients

    Science.gov (United States)

    Ma, Wei-Guo; Hou, Bin; Abdurusul, Adiljan; Gong, Ding-Xu; Tang, Yue; Chang, Qian; Xu, Jian-Ping

    2015-01-01

    Background Dysfunction of mechanical heart valve prostheses is an unusual but potentially lethal complication after mechanical prosthetic valve replacement. We seek to report our experience with mechanical valve dysfunction regarding etiology, surgical techniques and early outcomes. Methods Clinical data of 48 patients with mechanical valve dysfunction surgically treated between October 1996 and June 2011 were analyzed. Results Mean age was 43.7±10.9 years and 34 were female (70.8%). The median interval from primary valve implantation to dysfunction was 44.5 months (range, 1 hour to 20 years). There were 21 emergent and 27 elective reoperations. The etiology was thrombosis in 19 cases (39.6%), pannus in 12 (25%), thrombosis and pannus in 11 (22.9%), improper disc orientation in 2 (4.1%), missing leaflet in 1 (2.1%), excessively long knot end in 1 (2.1%), endogenous factor in 1 (2.1%) and unidentified in 1 (2.1%). Surgical procedure was mechanical valve replacement in 37 cases (77.1%), bioprosthetic valve replacement in 7 (14.9%), disc rotation in 2 (4.2%) and excision of excessive knot end in 1 (2.1%). Early deaths occurred in 7 patients (14.6%), due to low cardiac output in 3 (6.3%), multi-organ failure in 2 (4.2%) and refractory ventricular fibrillation in 2 (4.2%). Complications occurred in 10 patients (20.8%). Conclusions Surgical management of mechanical valve dysfunction is associated with significant mortality and morbidity. Earlier identification and prompt reoperation are vital to achieving better clinical outcomes. The high incidence of thrombosis in this series highlights the need for adequate anticoagulation and regular follow-up after mechanical valve replacement. PMID:26793354