Science.gov

Sample records for admission valve means

  1. 32. 48' MILL STEAM ENGINE ADMISSION BOX (?), STEAM VALVE, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. 48' MILL STEAM ENGINE ADMISSION BOX (?), STEAM VALVE, AND REVERSING MECHANISM LIFTING CYLINDER. - U.S. Steel Homestead Works, 48" Plate Mill, Along Monongahela River, Homestead, Allegheny County, PA

  2. Means for variable valve timing for engine

    SciTech Connect

    Oyaizu, T.

    1988-02-23

    A variable timing camshaft drive for an internal combustion engine is described having a first cylinder bank, a first camshaft rotating about a first axis for operating at least one valve associated with the first cylinder bank, a second cylinder bank disposed at an angle to the first cylinder bank, a second camshaft rotating about a second axis for operating at least one valve associated with the second cylinder bank, a drive sprocket driven by the engine and rotatable about a third axis, a single flexible transmitter trained about the first and the second camshafts and the drive sprocket for driving the first and the second camshafts in unison with each other, and means for simultaneously rotating the first and the second camshafts in the same direction relative to the drive sprocket for simultaneously changing the events of the valves operated by the camshafts in the same sense.

  3. Overhead camshaft engine valve train with slack take up means

    SciTech Connect

    Hayashi, Y.

    1987-03-03

    A valve train of an overhead camshaft engine is described comprising: a valve stem; a valve operating cam; a rocker arm operatively engaged with the valve stem and the cam for transferring motion from the cam to the valve stem and having at a part where it is operatively engaged with the cam a hole; a tappet reciprocatingly mounted in the hole in a manner to define an oil pressure chamber variable in volume in accordance with actual movement of the tappet and having an end protruding from the rocker arm to contact the cam; a source of pressurized oil; passageway means for providing communication between the source of pressurized oil and the oil pressure chamber; check valve means operatively connected with the passageway means for preventing a return flow out of the oil pressure chamber; a spring disposed in the oil pressure chamber to urge the tappet in the direction causing the oil pressure chamber to increase in volume to thereby take up slack in the valve train; and an oil releasing passageway having one end opening directly into the uppermost part of the oil pressure chamber and another end opening to the outside of the rocker arm.

  4. Usefulness of thrombocytopenia at admission as a prognostic marker in native valve left-sided infective endocarditis.

    PubMed

    Ferrera, Carlos; Vilacosta, Isidre; Fernández, Cristina; López, Javier; Sarriá, Cristina; Olmos, Carmen; Vivas, David; Sáez, Carmen; Sánchez-Enrique, Cristina; Ortiz, Carlos; San Román, José Alberto

    2015-04-01

    In-hospital mortality of patients with infective endocarditis (IE) remains exceedingly high. Quick recognition of parameters accurately identifying high-risk patients is of paramount importance. The objective of this study was to analyze the incidence and severity of thrombocytopenia at presentation and its prognostic impact in patients with native valve left-sided IE. We studied a cohort of 533 consecutive episodes of native valve left-sided IE prospectively recruited. We distinguished 2 groups: group I (n = 175), episodes who had thrombocytopenia at admission, and group II (n = 358) gathered all the episodes who did not. Thrombocytopenia at admission was defined as a platelet count of <150,000/μl. No differences were found in the need for surgery, but in-hospital mortality was significantly higher in patients with thrombocytopenia (p <0.001). Mortality rate was associated with the degree of thrombocytopenia (p <0.001). In the multivariable analysis, thrombocytopenia at admission was an independent predictor of higher mortality (p = 0.002). A synergistic interaction between thrombocytopenia and Staphylococcus aureus on mortality risk was also observed (p = 0.04). In conclusion, thrombocytopenia at admission is an early risk marker of increased mortality in patients with native valve left-sided IE. Mortality rates increased with increasing severity of thrombocytopenia. Thrombocytopenia at admission should be used as an early marker for risk stratification in patients with native valve IE to identify those at risk of complicated in-hospital evolution and increased mortality.

  5. Valve timing control means for engine

    SciTech Connect

    Oyaizu, T.

    1987-08-11

    This patent describes a double overhead camshaft drive arrangement comprising a cylinder head, first and second camshafts journaled by the cylinder head, respective first and second driven pulleys affixed for rotation with respective of the camshafts about first and second, parallel axis, a drive pulley affixed for rotation with a drive shaft about a third axis parallel to the first and second axis to define with the first and second axes the apicies of a triangle, flexible transmitter means trained around the pulleys for driving the camshafts from the drive shaft. The improvement consists of an idler pulley disposed between the driven pulleys and rotatable about a fourth axis lying within the triangle, the flexible transmitter means passing over one of the driven pulleys then across the idler pulley and finally over the other of the driven pulleys and engaging substantially more than 180 degrees of the circumference of each of the driven pulleys and of the idler pulley, means for adjusting the timing relationship between the camshaft and the drive shaft comprising a timing lever supported for pivotal movement about an adjustment axis offset from the first, second and third axes. The idler pulley is carried by the timing lever, and means for pivoting the timing lever about its adjustment axis for rotating the camshafts relative to the drive shaft.

  6. Means for positively seating a piezoceramic element in a piezoelectric valve during inlet gas injection

    DOEpatents

    Wright, Kenneth E.

    1994-01-01

    A piezoelectric valve in a gas delivery system includes a piezoceramic element bonded to a valve seal and disposed over a valve seat, and retained in position by an O-ring and a retainer; an insulating ball normally biased by a preload spring against the piezoceramic element; an inlet gas port positioned such that upon admission of inlet gas into the valve, the piezoceramic element is positively seated. The inlet gas port is located only on the side of the piezoceramic element opposite the seal.

  7. Means for positively seating a piezoceramic element in a piezoelectric valve during inlet gas injection

    DOEpatents

    Wright, K.E.

    1994-08-23

    A piezoelectric valve in a gas delivery system includes a piezoceramic element bonded to a valve seal and disposed over a valve seat, and retained in position by an O-ring and a retainer; an insulating ball normally biased by a preload spring against the piezoceramic element; an inlet gas port positioned such that upon admission of inlet gas into the valve, the piezoceramic element is positively seated. The inlet gas port is located only on the side of the piezoceramic element opposite the seal. 3 figs.

  8. VALVE

    DOEpatents

    Arkelyan, A.M.; Rickard, C.L.

    1962-04-17

    A gate valve for controlling the flow of fluid in separate concentric ducts or channels by means of a single valve is described. In one position, the valve sealing discs engage opposed sets of concentric ducts leading to the concentric pipes defining the flow channels to block flow therethrough. In another position, the discs are withdrawn from engagement with the opposed ducts and at the same time a bridging section is interposed therebetween to define concentric paths coextensive with and connecting the opposed ducts to facilitate flow therebetween. A wedge block arrangement is employed with each sealing disc to enable it to engage the ducts. The wedge block arrangement also facilitates unobstructcd withdrawal of the discs out of the intervening space between the sets of ducts. (AEC)

  9. Risk Assessment of Patients Undergoing Transfemoral Aortic Valve Implantation upon Admission for Post-Interventional Intensive Care and Surveillance: Implications on Short- and Midterm Outcomes

    PubMed Central

    Al-Rashid, Fadi; Kahlert, Philipp; Selge, Friederike; Hildebrandt, Heike; Patsalis, Polycarpos-Christos; Totzeck, Matthias; Mummel, Petra; Rassaf, Tienush; Jánosi, Rolf Alexander

    2016-01-01

    Background Several studies have found that standard risk scores inaccurately reflect risk in TAVI cohorts. The assessment of mortality risk upon post-interventional ICU admission is important to optimizing clinical management. This study sought to determine outcomes and factors affecting mortality in patients admitted to the intensive care unit (ICU) after transcatheter aortic valve implantation (TAVI), and to analyze and compare the predictive values of SAPS II and EuroSCORE. Methods and Findings 214 consecutive patients treated with transfemoral TAVI (2006–2012) admitted to the ICU in an academic tertiary-care university hospital, were included in this retrospective data analysis. The overall 30-day mortality rate was 7%. Non-survivors at 30-days and survivors showed differences in the rates of catecholamine therapy upon ICU admission (93 vs. 29%; p<0.001), stroke (20 vs. 1%;p<0.001), sepsis (27 vs. 2%;p<0.001), kidney injury (83 vs. 56%; log-rank p<0.001), catecholamine therapy (88 vs. 61%;log-rank p<0.001) and vascular complications (60 vs. 17%; p<0.001). Mean SAPS II score and predicted mortality were higher in non-survivors (38.1±7.0 vs. 29.9±6.2;p<0.001 and 23.1±11.7 vs. 10.5±8.2;p<0.001, retrospectively), whereas the logistic EuroSCORE could not discriminate between the groups (p = 0.555). Among the biochemical parameters, the maximum values of creatinine, procalcitonin, and troponin I during the first 48 h after ICU admission were significantly higher in non-survivors. Multivariate analysis of baseline characteristics and complications associated with two-year mortality showed no significant results. Conclusions The SAPS II is a good tool for estimating ICU mortality immediately after performing the TAVI procedure and provides valuable information for other known predictors of mortality. PMID:27880819

  10. Whom We Admit, What We Deny: The Meaning of Selective Admissions

    ERIC Educational Resources Information Center

    Kohn, Alfie

    2012-01-01

    What does it mean when a school, having rejected a child who applied for admission, explains that he or she just "isn't a good fit" with the school? At times, it is not clear how the decision to prevent a child from enrolling is best described as a lack of fit, particularly if the school's goals and priorities (a) correspond to what most parents…

  11. Valve driving means for V-type engine of vehicle

    SciTech Connect

    Uchiyama, K.; Suzuki, T.

    1987-02-17

    This patent describes a camshaft drive for an internal combustion engine comprising at least one cylinder, first and second camshafts supported for rotation about parallel and offset axes, an output shaft, and first timing drive means for driving the first camshaft directly from the output shaft on one side of the one cylinder. It also has a second timing drive means for driving the second camshaft from the first camshaft on the other side of the one cylinder.

  12. 49 CFR 236.508 - Interference with application of brakes by means of brake valve.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS..., AND APPLIANCES Automatic Train Stop, Train Control and Cab Signal Systems Standards § 236.508 Interference with application of brakes by means of brake valve. The automatic train stop, train control,...

  13. 49 CFR 236.508 - Interference with application of brakes by means of brake valve.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS..., AND APPLIANCES Automatic Train Stop, Train Control and Cab Signal Systems Standards § 236.508 Interference with application of brakes by means of brake valve. The automatic train stop, train control,...

  14. 49 CFR 236.508 - Interference with application of brakes by means of brake valve.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS..., AND APPLIANCES Automatic Train Stop, Train Control and Cab Signal Systems Standards § 236.508 Interference with application of brakes by means of brake valve. The automatic train stop, train control,...

  15. 49 CFR 236.508 - Interference with application of brakes by means of brake valve.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS..., AND APPLIANCES Automatic Train Stop, Train Control and Cab Signal Systems Standards § 236.508 Interference with application of brakes by means of brake valve. The automatic train stop, train control,...

  16. 49 CFR 236.508 - Interference with application of brakes by means of brake valve.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Interference with application of brakes by means of brake valve. 236.508 Section 236.508 Transportation Other Regulations Relating to Transportation..., AND APPLIANCES Automatic Train Stop, Train Control and Cab Signal Systems Standards §...

  17. Valve

    DOEpatents

    Cho, Nakwon

    1980-01-01

    A positive acting valve suitable for operation in a corrosive environment is provided. The valve includes a hollow valve body defining an open-ended bore for receiving two, axially aligned, spaced-apart, cylindrical inserts. One insert, designated the seat insert, terminates inside the valve body in an annular face which lies within plane normal to the axis of the two inserts. An elastomeric O-ring seal is disposed in a groove extending about the annular face. The other insert, designated the wedge insert, terminates inside the valve body in at least two surfaces oppositely inclined with respect to each other and with respect to a plane normal to the axis of the two inserts. An elongated reciprocable gate, movable between the two inserts along a path normal to the axis of the two inserts, has a first flat face portion disposed adjacent and parallel to the annular face of the seat insert. The gate has a second face portion opposite to the first face portion provided with at least two oppositely inclined surfaces for mating with respective inclined surfaces of the wedge insert. An opening is provided through the gate which registers with a flow passage through the two inserts when the valve is open. Interaction of the respective inclined surfaces of the gate and wedge insert act to force the first flat face portion of the gate against the O-ring seal in the seat insert at the limits of gate displacement where it reaches its respective fully open and fully closed positions.

  18. Wear resistant valve

    NASA Technical Reports Server (NTRS)

    Perkins, Gerald S. (Inventor)

    1980-01-01

    A valve which is resistant to wear caused by particles trapped between the valve seat and the valve member or poppet when the valve closes, including an outlet for directing washing fluid at the valve seat and/or sealing face of the poppet and means for supplying pressured fluid to the outlet at the time when the valve is closing.

  19. Invariant formulation for dispersed transverse isotropy in aortic heart valves: An efficient means for modeling fiber splay

    SciTech Connect

    Freed, Alan D.; Einstein, Daniel R.; Vesely, Ivan

    2005-11-01

    Most soft tissues possess an oriented architecture of collagen fiber bundles, conferring both anisotropy and nonlinearity to their elastic behavior. Transverse isotropy has often been assumed for a subset of these tissues that have a single macroscopically-identifiable preferred fiber direction. Micro-structural studies, however, suggest that, in some tissues, collagen fibers are approximately normally distributed about a mean preferred fiber direction. Structural constitutive equations that account for this dispersion of fibers have been shown to capture the mechanical complexity of these tissues quite well. Such descriptions, however, are computationally cumbersome for two-dimensional (2D) fiber distributions, let alone for fully three-dimensional (3D) fiber populations. In this paper, we develop a new constitutive law for such tissues, based on a novel invariant theory for dispersed transverse isotropy. The invariant theory is based on a novel closed-form ''splay invariant'' that can easily handle 3D fiber populations, and that only requires a single parameter in the 2D case. The model is polyconvex and fits biaxial data for aortic valve tissue as accurately as the standard structural model. Modification of the fiber stress-strain law requires no re-formulation of the constitutive tangent matrix, making the model flexible for different types of soft tissues. Most importantly, the model is computationally expedient in a finite-element analysis, demonstrated by modeling a bioprosthetic heart valve.

  20. Bellows sealed plug valve

    DOEpatents

    Dukas, Jr., Stephen J.

    1990-01-01

    A bellows sealed plug valve includes a valve body having an inlet passage and an outlet passage, a valve chamber between the inlet and outlet passages. A valve plug has substantially the same shape as the valve chamber and is rotatably disposed therein. A shaft is movable linearly in response to a signal from a valve actuator. A bellows is sealingly disposed between the valve chamber and the valve actuator and means are located between the bellows and the valve plug for converting linear movement of the shaft connected to the valve actuator to rotational movement of the plug. Various means are disclosed including helical thread mechanism, clevis mechanism and rack and pinion mechanism, all for converting linear motion to rotational motion.

  1. 30. Engine controls and valve gear, looking aft on main ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. Engine controls and valve gear, looking aft on main (promenade) deck level. Threaded admission valve lift rods (two at immediate left of chronometer) permit adjustment of valve timing in lower and upper admission valves of cylinder (left rod controls lower valve, right rod upper valve). Valve rods are lifted by jaw-like "wipers" during operation. Exhaust valve lift rods and wipers are located to right of chronometer. Crank at extreme right drives valve wiper shaft when engaged to end of eccentric rod, shown under "Crank Indicator" dial. Pair of handles to immediate left of admission valve rods control condenser water valves; handles to right of exhaust valve rods control feedwater flow to boilers from pumps. Gauges indicate boiler pressure (left) and condenser vacuum (right); "Crank Indicator" on wall aids engineer in keeping engine crank off "dead-center" at stop so that engine may be easily restarted. - Ferry TICONDEROGA, Route 7, Shelburne, Chittenden County, VT

  2. CAM operated fuel valve

    SciTech Connect

    Kelly, S.T.; Katchka, J.R.

    1991-09-03

    This patent describes improvement in a fuel control valve construction comprising a housing means having an inlet means adapted to be interconnected to a fuel source and a main outlet means adapted to be interconnected to a main burner means, the housing means having a main valve seat for interconnecting the inlet means with the main outlet means, the housing means having a movable main valve member for opening and closing the main valve seat, the housing means having a movable lever operatively associated with the main valve member and having a manually operable actuator means for controlling the operating positions of the lever, the lever having an intermediate cam follower portion and opposed ends disposed on each side of the cam follower portion with one end of the opposed ends being pivotally mounted to the housing means and with the other end of the opposed ends for operating the main valve member, the housing means having biasing means operatively interconnected to the lever to tend to pivot the lever in one direction that opens the main valve member away from its the main valve seat. The improvement comprises; the housing means has a thermostatically controlled means that is operatively associated with the lever and is adapted to engage and hold the lever in a position wherein the main valve member is in a closed condition against its the main valve seat when the thermostatically controlled means is in one operating condition thereof and the actuator means is in the on condition thereof.

  3. Double valve Implantation

    PubMed Central

    Stassano, Paolo; Mannacio, Vito; Musumeci, Antonino; Golino, Alessandro; Maida, Piero; Ferrigno, Vincenzo; Buonocore, Gaetano; Spampinato, Nicola

    1991-01-01

    From January 1976 through December 1987, 194 patients with a mean age of 43.3 ± 13.7 years (range, 11 to 74 years) underwent double (mitral and aortic) replacement of native valves with 8 types of bioprostheses: Carpentier-Edwards, 127 valves; Hancock, 76 valves; Liotta-Bioimplant, 57 valves; Ionescu-Shiley, 53 valves; Vascor, 27 valves; Carpentier-Edwards Pericardial, 22 valves; Angell-Shiley, 20 valves; and Implamedic, 6 valves. Concomitant cardiac procedures were performed in 25 patients (12.8%). There were 18 operative deaths (9.27%). Our retrospective analysis was restricted to 352 bioprostheses implanted in the 176 patients who survived surgery and were considered at risk for valve tissue failure. The overall cumulative duration of follow-up was 1,174.1 patient-years (range, 1 to 13 years). The durations of follow-up for specific valves were: Carpentier-Edwards, 920.2 valve-years; Hancock, 383.8 valve-years; Liotta-Bioimplant, 310.2 valve-years; Ionescu-Shiley, 357.7 valve-years; Vascor, 131.2 valve-years; Carpentier-Edwards Pericardial, 52.0 valve-years; Angell-Shiley, 167.0 valve-years; and Implamedic, 31.0 valve-years. Thirty patients had thromboembolic accidents, for a linearized incidence of 2.5% per patient-year. At 13 years, the actuarial freedom from thromboembolic accidents was 85.8% ± 10.7%. Nine patients had endocarditis, for a linearized incidence of 0.7% per patient-year. At 13 years, the actuarial freedom from endocarditis was 92.0% ± 1.5%. Twenty-four patients had valve tissue failure, for a cumulative linearized incidence of 1.87% per valve-year. The cumulative actuarial probability of freedom from valve tissue failure was 78.6% ± 3.7% at 10 years and 51.2% ± 10.7% at 13 years. The 24 patients with valve tissue failure all underwent reoperation: 20 of these had double valve replacement, 3 had aortic valve replacement alone, and 1 had mitral valve replacement alone. The mean interval between initial valve implantation and reoperation was

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

    PubMed

    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.

  5. Pump isolation valve

    DOEpatents

    Kinney, Calvin L.; Wetherill, Todd M.

    1983-08-02

    The pump isolation valve provides a means by which the pump may be selectively isolated from the remainder of the coolant system while being compatible with the internal hydraulic arrangement of the pump during normal operation of the pump. The valve comprises a valve cylinder disposed around the pump and adjacent to the last pump diffuser with a turning vane attached to the lower end of the valve cylinder in a manner so as to hydraulically match with the discharge diffuser. The valve cylinder is connected to a drive means for sliding the valve cylinder relative to the diffuser support cylinder so as to block flow in either direction through the discharge diffuser when the valve is in the closed position and to aid in the flow of the coolant from the discharge diffuser by means of the turning vane when the valve is in the open position.

  6. Shocking Admission

    ERIC Educational Resources Information Center

    Hoover, Eric; Millman, Sierra

    2007-01-01

    Marilee Jones's career had been a remarkable success. She joined Massachusetts Institute of Technology's (MIT's) admissions office in 1979, landing a job in Cambridge at a time when boys ruled the sandbox of the admissions profession. Her job was to help MIT recruit more women, who then made up less than one-fifth of the institute's students. She…

  7. Dump valve assembly

    DOEpatents

    Owen, T.J.

    1984-01-01

    A dump valve assembly comprising a body having a bore defined by a tapered wall and a truncated spherical valve member adapted to seat along a spherical surface portion thereof against said tapered wall. Means are provided for pivoting said valve member between a closed position engagable with said tapered wall and an open position disengaged therefrom.

  8. Safety valve

    DOEpatents

    Bergman, Ulf C.

    1984-01-01

    The safety valve contains a resilient gland to be held between a valve seat and a valve member and is secured to the valve member by a sleeve surrounding the end of the valve member adjacent to the valve seat. The sleeve is movable relative to the valve member through a limited axial distance and a gap exists between said valve member and said sleeve.

  9. Bidirectional piston valve

    DOEpatents

    Fischer, Harry C.

    1977-01-01

    This invention is a reversing valve having an inlet, an outlet, and an inlet-outlet port. The valve is designed to respond to the introduction of relatively high-pressure fluid at its inlet or, alternatively, of lower-pressure fluid at its inlet-outlet port. The valve includes an axially slidable assembly which is spring-biased to a position where it isolates the inlet and connects the inlet-outlet port to the outlet. The admission of high-pressure fluid to the inlet displaces the slidable assembly to a position where the outlet is isolated and the inlet is connected to the inlet-outlet port. The valve is designed to minimize pressure drops and leakage. It is of a reliable and comparatively simple design.

  10. Valve assembly for internal combustion engine

    SciTech Connect

    Wakeman, R.J.; Shea, S.F.

    1989-09-05

    This patent describes an improvement in a valve assembly for an internal combustion engine of the type including a valve having a valve stem, a valve guideway for mounting this valve for reciprocal strokes between opened and seated position, and spring means for biasing the valve into the seated position. The improvement comprising a valve spool of greater cross-sectional diameter as compared to the valve stem, and a valve spool guideway within which the valve spool is movable during the strokes of the valve, an upper surface of the valve spool and a portion of the spool guideway collectively establishing a damper chamber which varies in volume during the valve strokes. a feed passage for introducing oil into the damper chamber, and a bleed passage for discharging oil from the damper chamber. The bleed passages each laterally opening into the valve spool guideway.

  11. ELECTROSTRICTION VALVE

    DOEpatents

    Kippenhan, D.O.

    1962-09-25

    An accurately controlled, pulse gas valve is designed capable of delivering output pulses which vary in length from one-tenth millisecond to one second or more, repeated at intervals of a few milliseconds or- more. The pulsed gas valve comprises a column formed of barium titanate discs mounted in stacked relation and electrically connected in parallel, with means for applying voltage across the discs to cause them to expand and effect a mechanical elongation axially of the column. The column is mounted within an enclosure having an inlet port and an outlet port with an internal seat in communication with the outlet port, such that a plug secured to the end of the column will engage the seat of the outlet port to close the outlet port in response to the application of voltage is regulated by a conventional electronic timing circuit connected to the column. (AEC)

  12. Valve mechanism having variable valve timing

    SciTech Connect

    Oda, H.; Masuda, S.; Morita, Y.

    1986-04-08

    This patent describes a valve mechanism for an internal combustion engine which consists of a camshaft rotatable about a longitudinal axis and having a cam formed thereon, a swingable member mounted for swinging movement about the longitudinal axis of the camshaft and formed with a tappet receiving hole. A valve tapper is received in the tappet receiving hole for a slidable movement along the tappet receiving hole. The tappet has a cam which engages the surface at one end and a stem engages the surface at the other end. A valve stem is mounted for axial movement and engaged at one end with the stem engaging, surface of the tappet to be actuated thereby. A valve timing control swingably moves the swingable member and the tappet about the camshaft axis in accordance with predetermined engine operating conditions to thereby change valve opening and valve closing timing. The control includes means for holding the swingable member at a first position. The tappet and valve stem are in contact at a first position on the stem engaging surface of the tappet and the direction of the slidable movement of the tappet is aligned with the direction of the axial movement of the valve stem at least under heavy load, high speed engine operation, and for moving the swingable member from the first position to a second position. The tappet and valve stem are in contact at a second position on the stem engaging surface of the tappet at low speed engine operation to effect a change in valve opening and valve closing timing.

  13. Compact gate valve

    DOEpatents

    Bobo, Gerald E.

    1977-01-01

    This invention relates to a double-disc gate valve which is compact, comparatively simple to construct, and capable of maintaining high closing pressures on the valve discs with low frictional forces. The valve casing includes axially aligned ports. Mounted in the casing is a sealed chamber which is pivotable transversely of the axis of the ports. The chamber contains the levers for moving the valve discs axially, and an actuator for the levers. When an external drive means pivots the chamber to a position where the discs are between the ports and axially aligned therewith, the actuator for the levers is energized to move the discs into sealing engagement with the ports.

  14. All metal valve structure for gas systems

    DOEpatents

    Baker, Ray W.; Pawlak, Donald A.; Ramey, Alford J.

    1984-11-13

    A valve assembly with a resilient metal seat member is disclosed for providing a gas-tight seal in a gas handling system. The valve assembly also includes a valve element for sealing against the valve seat member; and an actuating means for operating the valve element. The valve seat member is a one-piece stainless steel ring having a central valve port and peripheral mounting flange, and an annular corrugation in between. A groove between the first and second ridges serves as a flexure zone during operation of the valve member and thus provides the seating pressure between the inner ridge or valve seat and the valve element. The outer annular ridge has a diameter less than said valve element to limit the seating motion of the valve element, preventing non-elastic deformation of the seat member.

  15. ULTRA HIGH VACUUM VALVE

    DOEpatents

    Fry, W.A.

    1962-05-29

    A valve for high vacuum applications such as the CStellarator where chamber pressures as low as 2 x 10/sup -10/ mm Hg are necessary is designed with a line-of-sight path through the valve for visual inspection of the contents of reactants in such chambers. The valve comprises a turnable resilient metal ball having an aperture therethrough, means for selectively turning the ball to rotate the axis of its line-of-sight path, and soft, deformable opposing orifices that are movable relatively toward said ball to seal with opposite ball surfaces upon said movement of said axis of said line-of-sight path. The valve also includes a bellows seal connected between said orifices and internal actuating means that eliminates the requirement for gasketed turnable valve closing stems. (AEC)

  16. Heart valve surgery - discharge

    MedlinePlus

    ... surgery - minimally invasive Aortic valve surgery - open Bicuspid aortic valve Endocarditis Heart valve surgery Mitral valve prolapse Mitral valve surgery - minimally invasive Mitral valve surgery - open Pulmonary valve stenosis Smoking - tips on how to quit Patient Instructions ...

  17. Check valve

    DOEpatents

    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.

  18. Check valve

    DOEpatents

    Upton, Hubert Allen; Garcia, Pablo

    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.

  19. 14 CFR 125.137 - Oil valves.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Oil valves. 125.137 Section 125.137....137 Oil valves. (a) Each oil valve must— (1) Comply with § 125.155; (2) Have positive stops or... the valve. (b) The closing of an oil shutoff means must not prevent feathering the propeller,...

  20. 14 CFR 125.137 - Oil valves.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Oil valves. 125.137 Section 125.137....137 Oil valves. (a) Each oil valve must— (1) Comply with § 125.155; (2) Have positive stops or... the valve. (b) The closing of an oil shutoff means must not prevent feathering the propeller,...

  1. 14 CFR 125.137 - Oil valves.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  2. 14 CFR 125.137 - Oil valves.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Oil valves. 125.137 Section 125.137....137 Oil valves. (a) Each oil valve must— (1) Comply with § 125.155; (2) Have positive stops or... the valve. (b) The closing of an oil shutoff means must not prevent feathering the propeller,...

  3. 14 CFR 125.137 - Oil valves.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Oil valves. 125.137 Section 125.137....137 Oil valves. (a) Each oil valve must— (1) Comply with § 125.155; (2) Have positive stops or... the valve. (b) The closing of an oil shutoff means must not prevent feathering the propeller,...

  4. Valve stem and packing assembly

    DOEpatents

    Wordin, John J.

    1991-01-01

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  5. Valve stem and packing assembly

    DOEpatents

    Wordin, J.J.

    1991-09-03

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents over tightening of the retaining nut and the resulting excessive friction between stem and stem packing. 2 figures.

  6. A changing tide: what the new 'foundations of behavior' section of the 2015 medical college admissions test® might mean for undergraduate neuroscience programs.

    PubMed

    Roxanne Prichard, J

    2015-01-01

    Each year over 50,000 college students and alumni take the Medical College Admissions Test® (MCAT) and apply for admissions to medical school. After an extensive review process, the MCAT has undergone a major revision in form and content in order to better reflect the competencies medical students will need to be successful in their training and practice. Starting in April 2015, for the first time since the test's inception, the MCAT will include social and behavioral sciences content. The new section of the MCAT exam titled "The Psychological, Social and Biological Foundations of Behavior" will test pre-health competencies that combine content knowledge with scientific inquiry and reasoning skills. Anticipating growing interest in curriculum related to the new competency based content on the exam, the AAMC (Association of American Medical Colleges) established the Pre-health Collection within MedEdPORTAL's iCollaborative, a free repository of teaching resources. This online space gives faculty members the opportunity to share access to instructional resources in order to prepare or revise courses to include pre-health competencies. As a result of the increased content related to mind-body connections, undergraduate pre-medical students will be more likely to enroll in neuroscience courses to learn these competencies, or declare neuroscience majors, as the typical neuroscience major course requirements now meet most of the suggested pre-requisite competencies for medical school.

  7. Piston and valve assembly

    SciTech Connect

    Rolder, G. K.

    1985-10-01

    A downhole hydraulically actuated pump assembly of either the free or fixed type lifts formation fluid from the bottom of a borehole to the surface of the ground. The downhole pump has a power piston which actuates a production plunger. A valve means is concentrically arranged within the power piston. A stationary, hollow valve control rod extends through the power piston and through the valve means, with a lower marginal end of the control rod terminating within the production plunger. Power fluid flows through the control rod and to the valve means. As the power piston reciprocates within the engine cylinder, means on the control rod actuates the valve means between two alternant positions so that power fluid is applied to the bottom face of the power piston to thereby cause the power piston to reciprocate upward; and thereafter, the control rod causes the valve means to shift to the other position, whereupon spent power fluid is exhausted from the engine cylinder. The spent power fluid is admixed with production fluid and is conducted to the surface of the ground.

  8. Hydrogen gas relief valve

    DOEpatents

    Whittlesey, Curtis C.

    1985-01-01

    An improved battery stack design for an electrochemical system having at least one cell from which a gas is generated and an electrolyte in communication with the cell is described. The improved battery stack design features means for defining a substantially closed compartment for containing the battery cells and at least a portion of the electrolyte for the system, and means in association with the compartment means for selectively venting gas from the interior of the compartment means in response to the level of the electrolyte within the compartment means. The venting means includes a relief valve having a float member which is actuated in response to the level of the electrolyte within the compartment means. This float member is adapted to close the relief valve when the level of the electrolyte is above a predetermined level and open the relief valve when the level of electrolyte is below this predetermined level.

  9. Valve Disease

    MedlinePlus

    ... valves in the heart: tricuspid, pulmonary, mitral, and aortic. Two types of problems can disrupt blood flow though the valves: regurgitation or stenosis. Regurgitation is also called insufficiency or incompetence. Regurgitation ...

  10. Fast valve

    DOEpatents

    Van Dyke, W.J.

    1992-04-07

    A fast valve is disclosed that can close on the order of 7 milliseconds. It is closed by the force of a compressed air spring with the moving parts of the valve designed to be of very light weight and the valve gate being of wedge shaped with O-ring sealed faces to provide sealing contact without metal to metal contact. The combination of the O-ring seal and an air cushion create a soft final movement of the valve closure to prevent the fast air acting valve from having a harsh closing. 4 figs.

  11. Fast valve

    DOEpatents

    Van Dyke, William J.

    1992-01-01

    A fast valve is disclosed that can close on the order of 7 milliseconds. It is closed by the force of a compressed air spring with the moving parts of the valve designed to be of very light weight and the valve gate being of wedge shaped with O-ring sealed faces to provide sealing contact without metal to metal contact. The combination of the O-ring seal and an air cushion create a soft final movement of the valve closure to prevent the fast air acting valve from having a harsh closing.

  12. THERMALLY OPERATED VAPOR VALVE

    DOEpatents

    Dorward, J.G. Jr.

    1959-02-10

    A valve is presented for use in a calutron to supply and control the vapor to be ionized. The invention provides a means readily operable from the exterior of the vacuum tank of the apparatuss without mechanical transmission of forces for the quick and accurate control of the ionizing arc by a corresponding control of gas flow theretos thereby producing an effective way of carefully regulating the operation of the calutron. The invention consists essentially of a tube member extending into the charge bottle of a calutron devices having a poppet type valve closing the lower end of the tube. An electrical heating means is provided in the valve stem to thermally vary the length of the stem to regulate the valve opening to control the flow of material from the charge bottle.

  13. FLUID PRESSURE AND CAM OPERATED VACUUM VALVE

    DOEpatents

    Batzer, T.H.

    1963-11-26

    An ultra-high vacuum valve that is bakable, reusable, and capable of being quickly opened and closed is described. A translationally movable valve gate having an annular ridge is adapted to contact an annular soft metal gasket disposed at the valve seat such that the soft metal gasket extends beyond the annular ridge on all sides. The valve gate is closed, by first laterally aligning the valve gate with the valve seat and then bringing the valve gate and valve seat into seating contact by the translational movement of a ramp-like wedging means that engages similar ramp-like stractures at the base of the valve gate to force the valve gate into essentially pressureless contact with the annular soft metal gasket. This gasket is then pressurized from beneath by a fluid thereby effecting a vacuura tight seal between the gasket and the ridge. (AEC)

  14. Depressurization valve

    DOEpatents

    Skoda, G.I.

    1989-03-28

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

  15. Sliding-gate valve

    DOEpatents

    Usnick, George B.; Ward, Gene T.; Blair, Henry O.; Roberts, James W.; Warner, Terry N.

    1979-01-01

    This invention is a novel valve of the slidable-gate type. The valve is designed especially for long-term use with highly abrasive slurries. The sealing surfaces of the gate are shielded by the valve seats when the valve is fully open or closed, and the gate-to-seat clearance is swept with an inflowing purge gas while the gate is in transit. A preferred form of the valve includes an annular valve body containing an annular seat assembly defining a flow channel. The seat assembly comprises a first seat ring which is slidably and sealably mounted in the body, and a second seat ring which is tightly fitted in the body. These rings cooperatively define an annular gap which, together with passages in the valve body, forms a guideway extending normal to the channel. A plate-type gate is mounted for reciprocation in the guideway between positions where a portion of the plate closes the channel and where a circular aperture in the gate is in register with the channel. The valve casing includes opposed chambers which extend outwardly from the body along the axis of the guideway to accommodate the end portions of the gate. The chambers are sealed from atmosphere; when the gate is in transit, purge gas is admitted to the chambers and flows inwardly through the gate-to-seat-ring, clearance, minimizing buildup of process solids therein. A shaft reciprocated by an external actuator extends into one of the sealed chambers through a shaft seal and is coupled to an end of the gate. Means are provided for adjusting the clearance between the first seat ring and the gate while the valve is in service.

  16. Engine valve train module

    SciTech Connect

    Wirth, R.C.; De Klep, E.L.

    1988-01-26

    In a reciprocating internal combustion engine of the type having an engine block means defining at least one cylinder with a first port and a second port in flow communication therewith, a first valve and a second valve reciprocably located to control flow through the first and second ports, respectively, and normally biased to a port closed position, the improvement is described comprising a valve train module that includes a housing adapted to be secured by machine screws to the engine block means above the first and second valves; an engine driven camshaft having axial spaced apart first and second cam lobes operatively supported for rotation in the housing; a lifter guide bore in the housing located substantially coaxial with the reciprocating axis of the first valve; a direct acting hydraulic lash adjuster operatively supported in the lifter guide bore with one end thereof engaging the first cam lobe and at its opposite end being operatively connected to the first valve. A follower guide bore is in the housing operatively aligned relative to the second cam lobe; a hollow rocker shaft is operatively fixed in the housing in parallel spaced apart relationship to the engine driven camshaft; a rocker arm pivotably supported intermediate its ends by the rocker shaft.

  17. Meaning

    NASA Astrophysics Data System (ADS)

    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.

  18. Problem: Heart Valve Stenosis

    MedlinePlus

    ... valve . Learn about the different types of stenosis: Aortic stenosis Tricuspid stenosis Pulmonary stenosis Mitral stenosis Outlook for ... Disease "Innocent" Heart Murmur Problem: Valve Stenosis - Problem: Aortic Valve Stenosis - Problem: Mitral Valve Stenosis - Problem: Tricuspid Valve Stenosis - ...

  19. Seeking the Admission Hybrid

    ERIC Educational Resources Information Center

    Lucido, Jerome A.

    2012-01-01

    When one thinks of seminal publications in college admission, the first piece that comes to mind is B. Alden Thresher's "College Admissions in the Public Interest" (1966). Thresher's work, relevant to this day, is credited with being the foundational document of the admission profession. McDonough and Robertson's 1995 study, commissioned by NACAC,…

  20. Valve system incorporating single failure protection logic

    DOEpatents

    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.

  1. Actuating mechanism for multiple valve internal combustion engine

    SciTech Connect

    Aoi, K.; Tsuchida, N.

    1986-10-21

    A valve train is described for an internal combustion engine. The valve train has cylinder bore having a bore axis, a first poppet valve supported for reciprocation along a valve axis defined by its stem, and a second poppet valve supported for reciprocation about a valve axis defined by its stem. The valve train also has a camshaft supported for rotation about a rotational axis intersected by the first poppet valve stem axis and extending parallel to a plane containing the bore axis. A cam means of the camshaft is for opening directly the first valve and a rocker arm is supported for pivotal movement. The cam means of the camshaft is for pivoting the rocker arm, and means on the rocker arm is operative to actuate the second valve upon pivotal movement of the rocker arm. The valve axes lies on the same side of the plane as the rotational axis.

  2. Valve-"Health"-Monitoring System

    NASA Technical Reports Server (NTRS)

    Jensen, Scott L.; Drouant, George J.

    2009-01-01

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

  3. Depressurization valve

    DOEpatents

    Skoda, George I.

    1989-01-01

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

  4. 14 CFR 25.995 - Fuel valves.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel valves. 25.995 Section 25.995... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System Components § 25.995 Fuel valves. In addition to the requirements of § 25.1189 for shutoff means, each fuel valve must— (a) (b) Be supported...

  5. 14 CFR 25.995 - Fuel valves.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fuel valves. 25.995 Section 25.995... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System Components § 25.995 Fuel valves. In addition to the requirements of § 25.1189 for shutoff means, each fuel valve must— (a) (b) Be supported...

  6. 14 CFR 25.995 - Fuel valves.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel valves. 25.995 Section 25.995... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System Components § 25.995 Fuel valves. In addition to the requirements of § 25.1189 for shutoff means, each fuel valve must— (a) (b) Be supported...

  7. 14 CFR 25.995 - Fuel valves.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel valves. 25.995 Section 25.995... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System Components § 25.995 Fuel valves. In addition to the requirements of § 25.1189 for shutoff means, each fuel valve must— (a) (b) Be supported...

  8. 14 CFR 25.995 - Fuel valves.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  9. Nuclear radiation actuated valve

    DOEpatents

    Christiansen, David W.; Schively, Dixon P.

    1985-01-01

    A nuclear radiation actuated valve for a nuclear reactor. The valve has a valve first part (such as a valve rod with piston) and a valve 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. The valve's first part is positioned to receive nuclear radiation from the nuclear reactor's fuel region. The valve's second part is positioned so that its nuclear radiation induced swelling is different from that of the valve's first part. The valve's second part also is 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.

  10. All-metal valve structure for gas systems

    DOEpatents

    Baker, R.W.; Pawlak, D.A.; Ramey, A.J.

    1982-06-10

    A valve assembly with a resilient metal seat member is disclosed for providing a gas-tight seal in a gas handling system. The valve assembly also includes a valve element for sealing against the valve seat member; and an actuating means for operating the valve element. The valve seat member is a one-piece stainless steel ring having a central valve port and peripheral mounting flange, and an annular corrugation in between. A groove between the first and second ridges serves as a flexure zone during operation of the valve member and thus provides the seating pressure between the inner ridge or valve seat and the valve element. The outer annular ridge has a diameter less than said valve element to limit the seating motion of the valve element, preventing non-elastic deformation of the seat member.

  11. A comparison of Q fever endocarditis with native valve endocarditis.

    PubMed

    Marrie, T J

    1990-01-01

    We compared 10 episodes (8 patients) of Q fever endocarditis with 27 episodes (27 patients) of native valve endocarditis. Patients with Q fever endocarditis were more likely to have weight loss (p less than 0.003), experience fatigue (p less than 0.07), have clubbing of the fingers (p less than 0.005), have a diastolic murmur at the time of admission (p less than 0.03), be anemic (p less than 0.05), have a normal white blood cell count (p less than 0.005), and have a higher serum globulin concentration (p less than 0.007). While valve replacement was required for 50% of the episodes in both groups of patients, it was required later--mean 107 days following the onset of treatment--for the Q fever patients than for the native valve patients--mean 27 days. The mortality rates for these two diseases were not significantly different (30% for native endocarditis vs. 12.5% for Q fever endocarditis), but the Q fever patients experienced significantly fewer complications.

  12. Double-disc gate valve

    DOEpatents

    Wheatley, Seth J.

    1979-01-01

    This invention relates to an improvement in a conventional double-disc gate valve having a vertically movable gate assembly including a wedge, spreaders slidably engaged therewtih, 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 separtion 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.

  13. Solenoid-valve-controlled fuel injection device

    SciTech Connect

    Oshizawa, H.

    1988-12-06

    This patent describes a solenoid-valve-controlled fuel injection device comprising: a fuel injection pump having a pump cylinder, a plunger rotatably and reciprocably disposed in the pump cylinder in a fluid-tight manner and defining a fuel pressurization chamber between a distal end of the plunger and the pump cylinder, a drive shaft rotatable in synchronism with an output shaft of an internal combustion engine, means responsive to rotation of the drive shaft for reciprocably displacing the plunger to pressurize fuel in the pressurization chamber, and a fuel chamber for being supplied with fuel from a fuel tank in response to rotation of the drive shaft, whereby the pressurized fuel can be fed into cylinders of the internal combustion engine; a solenoid valve for selectively opening and closing a communication passage by which the pressurization chamber and the fuel chamber communicate with each other; valve opening delay time detecting means for detecting a valve opening delay time of the solenoid valve; valve closing delay time detecting means for detecting a valve closing delay time of the solenoid valve; valve closing period calculating means for calculating a valve closing time of the solenoid valve according to operating conditions of the internal combustion engine; target fuel injection time calculating means for calculating a target fuel injection time according to the operating conditions of the internal combustion engine.

  14. Valve operating system for an automotive engine

    SciTech Connect

    Maeda, S.

    1988-03-15

    In a valve operating system for an automotive engine having two or more intake valves for one cylinder, a camshaft having cams for operating the intake valves, the system is described comprising: one of the cams being rotatably and axially slidably mounted on the camshaft; clutch means for engaging the slidable cam with the camshaft at a predetermined angular position; shifting means for axially shifting the slidable cam to engage the cam with the camshaft by the clutch means.

  15. Elastodynamic analysis of the desmodromic valve train of a racing motorbike engine by means of a combined lumped/finite element model

    NASA Astrophysics Data System (ADS)

    Rivola, A.; Troncossi, M.; Dalpiaz, G.; Carlini, A.

    2007-02-01

    A combined lumped/finite element model of a portion of the desmodromic valve train of a racing motorbike engine was developed and validated in order to simulate the elastodynamic behaviour of such a particular timing system. The model includes the lumped parameter model of the belt transmission that drives the camshafts, the finite element model of the camshafts, and the lumped parameter model of two cam-valve mechanisms (one for each camshaft). The procedure to validate the model, based on experimental tests carried out on a test bench described here, is presented and discussed. The comparison between the numerical results and the experimental data shows that the effectiveness of the model is satisfactorily achieved. It will be possible, in a further study, to add the other cam-valve mechanisms and the missing external forces, in order to obtain a complete system model. Some possible applications of the presented model are provided in order to show how the overall model could be employed to perform both design optimisation and diagnostics.

  16. Josephson magnetic rotary valve

    SciTech Connect

    Soloviev, I. I.; Klenov, N. V.; Bakurskiy, S. V.; Bol'ginov, V. V.; Ryazanov, V. V.; Kupriyanov, M. Yu.; Golubov, A. A.

    2014-12-15

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

  17. Aortic Valve Regurgitation

    MedlinePlus

    ... valve. Also, a narrowing of the aortic valve (aortic stenosis) can be associated with leaking. High blood pressure (hypertension). High blood pressure may stretch the root of the aorta where the aortic valve sits. The valve flaps ( ...

  18. Mitral Valve Disease

    MedlinePlus

    ... Heart Disease Diseases of the arteries, valves, and aorta, as well as cardiac rhythm disturbances Aortic Valve ... are two main types of mitral valve disease: Stenosis – the valve does not open enough to allow ...

  19. What Admissions Officials Think

    ERIC Educational Resources Information Center

    Hoover, Eric

    2008-01-01

    Over the past two decades, college admissions has become a prime-time preoccupation. Most people know at least something about the process, especially if they have a teenager in high school and a college guide on their coffee table. Nonetheless, widespread public misconceptions persist about admissions requirements, the selection process, and the…

  20. The Administration of Admissions

    ERIC Educational Resources Information Center

    Campbell, Clifford C.

    1978-01-01

    Among all the tasks of the admissions officer in developing a successful marketing program, the hardest may be that of convincing other college administrators of the importance of admissions to the institution's survival. Discussed are long-range planning, budgeting, staff selection and training, and implementing a plan. (Author/LBH)

  1. Technology in International Admissions

    ERIC Educational Resources Information Center

    White, Elizabeth

    2012-01-01

    In a relatively short time, technology applications have become an essential feature of the admissions business. They make the jobs of international admissions professionals easier in many ways, allowing for more robust communication with applicants and counselors, a streamlined application process, and quicker access to information about…

  2. A calcified polymeric valve for valve-in-valve applications.

    PubMed

    Falahatpisheh, Ahmad; Morisawa, Daisuke; Toosky, Taraz T; Kheradvar, Arash

    2017-01-04

    The prevalence of aortic valve stenosis (AS) is increasing in the aging society. More recently, novel treatments and devices for AS, especially transcatheter aortic valve replacement (TAVR) have significantly changed the therapeutic approach to this disease. Research and development related to TAVR require testing these devices in the calcified heart valves that closely mimic a native calcific valve. However, no animal model of AS has yet been available. Alternatively, animals with normal aortic valve that are currently used for TAVR experiments do not closely replicate the aortic valve pathology required for proper testing of these devices. To solve this limitation, for the first time, we developed a novel polymeric valve whose leaflets possess calcium hydroxyapatite inclusions immersed in them. This study reports the characteristics and feasibility of these valves. Two types of the polymeric valve, i.e., moderate and severe calcified AS models were developed and tested by deploying a transcatheter valve in those and measuring the related hemodynamics. The valves were tested in a heart flow simulator, and were studied using echocardiography. Our results showed high echogenicity of the polymeric valve, that was correlated to the severity of the calcification. Aortic valve area of the polymeric valves was measured, and the severity of stenosis was defined according to the clinical guidelines. Accordingly, we showed that these novel polymeric valves closely mimic AS, and can be a desired cost-saving solution for testing the performance of the transcatheter aortic valve systems in vitro.

  3. 49 CFR 236.383 - Valve locks, valves, and valve magnets.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Valve locks, valves, and valve magnets. 236.383... Inspection and Tests § 236.383 Valve locks, valves, and valve magnets. Valve locks on valves of the non-cut-off type shall be tested at least once every three months, and valves and valve magnets shall...

  4. 49 CFR 236.383 - Valve locks, valves, and valve magnets.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  5. 49 CFR 236.383 - Valve locks, valves, and valve magnets.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Valve locks, valves, and valve magnets. 236.383... Inspection and Tests § 236.383 Valve locks, valves, and valve magnets. Valve locks on valves of the non-cut-off type shall be tested at least once every three months, and valves and valve magnets shall...

  6. 49 CFR 236.383 - Valve locks, valves, and valve magnets.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Valve locks, valves, and valve magnets. 236.383... Inspection and Tests § 236.383 Valve locks, valves, and valve magnets. Valve locks on valves of the non-cut-off type shall be tested at least once every three months, and valves and valve magnets shall...

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

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Valve locks, valves, and valve magnets. 236.383... Inspection and Tests § 236.383 Valve locks, valves, and valve magnets. Valve locks on valves of the non-cut-off type shall be tested at least once every three months, and valves and valve magnets shall...

  8. Valve operating mechanism for internal combustion engine

    SciTech Connect

    Nagahiro, K.; Ajiki, Y.; Katoh, M.; Inoue, K.

    1988-03-01

    A valve operating mechanism for operating a pair of valves of an internal combustion engine is described, comprising: a camshaft rotatable in synchronism with rotation of the internal combustion engine an having cams of different cam profiles; rocker arms held in sliding contact with the cams, respectively, for operating the valves according to the cam profiles of the cams; and means for independently selectively interconnecting and disconnecting selected of the rocker arms to operate the valves at different valve timings in low, medium and high speed ranges of the internal combustion engine.

  9. Valve operating mechanism for internal combustion engine

    SciTech Connect

    Inoue, K.; Nagahiro, K.; Ajiki, Y.; Katoh, M.

    1988-12-27

    A valve operating mechanism for operating a single valve of a particular cylinder of an internal combustion engine is described comprising: a camshaft rotatable in synchronism with rotation of the internal combustion engine; a plurality of cams on the camshaft with each of the cams bearing a different cam profile; a plurality of cam followers, each of which slidably engages one of the cams for selectively operating the valve according to the profile of the selected cam and one of which engages the valve; and means for selectively interconnecting and disconnecting the respective cam followers to operate the valve differently in different speed ranges of the internal combustion engine.

  10. Valve operating mechanism for internal combustion engine

    SciTech Connect

    Inoue, K.; Nagahiro, K.; Ajiki, Y.; Katoh, M.

    1988-12-13

    This patent describes a valve operating mechanism for operating valves of a particular cylinder of an internal combustion engine, comprising: a camshaft rotatable in synchronism with rotation of the internal combustion engine and having at least one cam; cam followers, one of which slidably engages with the cam for selectively operating the valves according to a cam profile of the cam; and means for selectively interconnecting and disconnecting the cam followers to operate the valves differently in different speed ranges of the internal combustion engine, the speed ranges including a range in which all of the valves remain inoperative.

  11. Piezoelectric valve

    SciTech Connect

    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.

  12. Excess flow shutoff valve

    DOEpatents

    Kiffer, Micah S.; Tentarelli, Stephen Clyde

    2016-02-09

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

  13. Advanced technology for space shuttle auxiliary propellant valves

    NASA Technical Reports Server (NTRS)

    Wichmann, H.

    1973-01-01

    Valves for the gaseous hydrogen/gaseous oxygen shuttle auxiliary propulsion system are required to feature low leakage over a wide temperature range coupled with high cycle life, long term compatibility and minimum maintenance. In addition, those valves used as thruster shutoff valves must feature fast response characteristics to achieve small, repeatable minimum impulse bits. These valve technology problems are solved by developing unique valve components such as sealing closures, guidance devices, and actuation means and by demonstrating two prototype valve concepts. One of the prototype valves is cycled over one million cycles without exceeding a leakage rate of 27 scc's per hour at 450 psia helium inlet pressure throughout the cycling program.

  14. Percutaneous implantation of CoreValve aortic prostheses in patients with a mechanical mitral valve.

    PubMed

    Bruschi, Giuseppe; De Marco, Federico; Oreglia, Jacopo; Colombo, Paola; Fratto, Pasquale; Lullo, Francesca; Paino, Roberto; Frigerio, Maria; Martinelli, Luigi; Klugmann, Silvio

    2009-11-01

    Concerns exist in the field of transcatheter aortic valve implantation regarding the treatment of patients with mechanical mitral valve for possible interference between the percutaneous aortic valve and the mechanical mitral prosthesis. We report our experience with percutaneous aortic valve implantation in 4 patients with severe aortic stenosis, previously operated on for mitral valve replacement with a mechanical prosthesis. All patients underwent uneventful percutaneous retrograde CoreValve implantation (CoreValve Inc, Irvine, CA). No deformation of the nitinol tubing of the prostheses (ie, neither distortion nor malfunction of the mechanical valve in the mitral position) occurred in any of the patients. All patients are alive and asymptomatic at a mean follow-up of 171 days.

  15. Student Admission and Attendance.

    ERIC Educational Resources Information Center

    Majestic, Ann L.

    1988-01-01

    Considers the North Carolina statutes that define the process for admitting students to public schools and ensuring their attendance. Examines cases relating to issues of school admission and compulsory attendance. (MLF)

  16. Hospice Admission Assessment.

    PubMed

    Moon, Paul J

    2017-04-01

    Hospice admission assessment is a pivotal encounter for patient/family and hospice representative. For patient/family, the admission is the threshold by which a particular level of care can commence and, symbolically, a certain marker in health status trajectory is reached. For hospice representative, the admission episode is an occasion to inaugurate an ambience that can serve to frame future hospice care experiences for the patient/family. Through a narrative lens, hospice admission assessment can be seen as experiential time and space, where patient's and family's stories are mindfully and deliberately witnessed and explored. Through the practice of narrative mining, the hospice representative can better understand others' offered stories of reality, which will better inform the plan of palliation and hospice care.

  17. Dump valve

    SciTech Connect

    Webber, J.C.

    1981-06-23

    A swab assembly is provided having a dump valve responsive to fluid pressure and drag which will dump the fluid load should either fluid load or drag or the effect of both fluid load and drag become abnormal. Also if the fluid pressure and/or drag become abnormal, the fluid load on the cup will be released and wash away foreign material causing abnormal drag. When the cup is dumped the pulling capabilities of the wireline truck can concentrate on overcoming the drag. The dump valve opens to wide open position and remains open to dump the fluid to assist in washing away solid materials above the cup. A swab assembly also is provided which with normal drag and an overload, may be pulled relatively slowly, but if pulled too rapidly will result in the load on the swab being dumped to protect the swab assembly and the pulling apparatus from damage. 15 claims.

  18. Hydraulic valve control system for internal combustion engines

    SciTech Connect

    Bowman, T.J.; LoRusso, J.A.; Kaufman, W.F.

    1992-07-07

    This patent describes a hydraulic engine valve actuating assembly for use in an internal combustion engine cylinder head having a poppet valve which is axially shiftable therein by a rotary camshaft, the hydraulic engine valve actuating assembly. It comprises a housing having a mounted surface to attach to the cylinder head immediately above the poppet valve, a master piston cooperating with the camshaft and sealingly engaging the first cavity; a slave piston cooperating with the poppet valve and sealingly engaging the housing second cavity; a hydraulic energy and fluid storage accumulator assembly affixed and sealingly engaged relative to the housing and being provided with a fluid port coupled with the housing fluid passageway; valve means; the housing including a third cavity coaxially aligned with the poppet valve; and the valve means including a reciprocal valve piston sealingly engaged within the third cavity.

  19. Mitral Valve Prolapse

    MedlinePlus

    ... Personal Stories Support Network: You're Not Alone Heart Valve Disease Symptoms Dr. Robert Bonow describes the symptoms that may alert you to heart valve disease. Valve Disease Resources Patient Guide: Understanding Your Heart ...

  20. Automatic shutoff valve

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

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

  1. Mitral Valve Prolapse

    MedlinePlus

    Mitral valve prolapse (MVP) occurs when one of your heart's valves doesn't work properly. The flaps of ... Migraine headaches Chest discomfort Most people who have mitral valve prolapse (MVP) don't need treatment because they ...

  2. Magnetically operated check valve

    NASA Technical Reports Server (NTRS)

    Morris, Brian G. (Inventor); Bozeman, Richard J., Jr. (Inventor)

    1994-01-01

    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.

  3. Magnetically operated check valve

    NASA Astrophysics Data System (ADS)

    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.

  4. Fast-Acting Valve

    NASA Technical Reports Server (NTRS)

    Wojciechowski, Bogdan V. (Inventor); Pegg, Robert J. (Inventor)

    2003-01-01

    A fast-acting valve includes an annular valve seat that defines an annular valve orifice between the edges of the annular valve seat, an annular valve plug sized to cover the valve orifice when the valve is closed, and a valve-plug holder for moving the annular valve plug on and off the annular valve seat. The use of an annular orifice reduces the characteristic distance between the edges of the valve seat. Rather than this distance being equal to the diameter of the orifice, as it is for a conventional circular orifice, the characteristic distance equals the distance between the inner and outer radii (for a circular annulus). The reduced characteristic distance greatly reduces the gap required between the annular valve plug and the annular valve seat for the valve to be fully open, thereby greatly reducing the required stroke and corresponding speed and acceleration of the annular valve plug. The use of a valve-plug holder that is under independent control to move the annular valve plug between its open and closed positions is important for achieving controllable fast operation of the valve.

  5. Additively Manufactured Main Fuel Valve Housing

    NASA Technical Reports Server (NTRS)

    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.

  6. Valve operating mechanism for internal combustion engine

    SciTech Connect

    Inoue, K.; Nagahiro, K.; Ajiki, Y.; Katoh, M.

    1988-12-06

    This patent describes a valve operating mechanism of operating valves of an internal combustion engine, comprising: a camshaft rotatable in synchronism with rotation of the internal combustion engine and having an array of three cams each having a different cam profile and including a high-speed cam position at one end of the array; three cam followers held in sliding contact with the cams, respectively, for operating the valves according to the cam profiles of the cams; and means for selectively interconnecting and disconnecting the cam followers to operate the valves at different valve timings in different speed ranges of the internal combustion engine, the speed ranges including a high-speed range in which all of the valves are controlled by the cam profile of the high-speed cam.

  7. 14 CFR 25.1025 - Oil valves.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Oil valves. 25.1025 Section 25.1025... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Oil System § 25.1025 Oil valves. (a) Each oil shutoff must meet the requirements of § 25.1189. (b) The closing of oil shutoff means may not prevent...

  8. 14 CFR 25.1025 - Oil valves.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Oil valves. 25.1025 Section 25.1025... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Oil System § 25.1025 Oil valves. (a) Each oil shutoff must meet the requirements of § 25.1189. (b) The closing of oil shutoff means may not prevent...

  9. 14 CFR 121.239 - Oil valves.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Oil valves. 121.239 Section 121.239..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.239 Oil valves. (a) Each oil... oil shutoff means must not prevent feathering the propeller, unless equivalent safety provisions...

  10. 14 CFR 25.1025 - Oil valves.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Oil valves. 25.1025 Section 25.1025... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Oil System § 25.1025 Oil valves. (a) Each oil shutoff must meet the requirements of § 25.1189. (b) The closing of oil shutoff means may not prevent...

  11. 14 CFR 25.1025 - Oil valves.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Oil valves. 25.1025 Section 25.1025... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Oil System § 25.1025 Oil valves. (a) Each oil shutoff must meet the requirements of § 25.1189. (b) The closing of oil shutoff means may not prevent...

  12. 14 CFR 121.239 - Oil valves.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Oil valves. 121.239 Section 121.239..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.239 Oil valves. (a) Each oil... oil shutoff means must not prevent feathering the propeller, unless equivalent safety provisions...

  13. 14 CFR 121.239 - Oil valves.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Oil valves. 121.239 Section 121.239..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.239 Oil valves. (a) Each oil... oil shutoff means must not prevent feathering the propeller, unless equivalent safety provisions...

  14. 14 CFR 25.1025 - Oil valves.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Oil valves. 25.1025 Section 25.1025... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Oil System § 25.1025 Oil valves. (a) Each oil shutoff must meet the requirements of § 25.1189. (b) The closing of oil shutoff means may not prevent...

  15. 14 CFR 121.239 - Oil valves.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Oil valves. 121.239 Section 121.239..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.239 Oil valves. (a) Each oil... oil shutoff means must not prevent feathering the propeller, unless equivalent safety provisions...

  16. 14 CFR 121.239 - Oil valves.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Oil valves. 121.239 Section 121.239..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.239 Oil valves. (a) Each oil... oil shutoff means must not prevent feathering the propeller, unless equivalent safety provisions...

  17. Prosthetic valve endocarditis. A survey.

    PubMed Central

    Ben Ismail, M; Hannachi, N; Abid, F; Kaabar, Z; Rougé, J F

    1987-01-01

    Fifty eight patients (aged 8-59 years, mean 27) treated for prosthetic valve endocarditis from January 1966 to January 1985 were studied retrospectively by review of case notes. There were 12 cases of early and 46 cases of late prosthetic valve endocarditis. These developed in 28 patients with an isolated aortic valve, in 26 with an isolated mitral valve, and in four with both aortic and mitral prosthetic valves. Streptococci were the most commonly isolated microorganisms, followed by staphylococci, Gram negative bacteria, and fungi. A surgical (34 cases) or a necropsy specimen (10 cases) from 44 cases was examined. Eighty two per cent of the patients had congestive heart failure. Twenty four of the 58 patients were medically treated and 17 died (70% mortality). Combined medical and surgical treatment was used in 34 patients; the main indication for surgery was congestive heart failure. Fourteen patients on combined treatment died (40% mortality). Persistent sepsis and prosthetic valve dehiscence were the most common early and late operative complications. The most important influences on outcome were congestive heart failure, the type of micro-organism, the severity and extent of anatomical lesions, the time of onset of prosthetic valve endocarditis, and the type of treatment. This survey indicates that only patients without congestive heart failure or embolic complications and with sensitive micro-organism should be treated medically. In view of the poor prognosis patients with prosthetic valve endocarditis associated with congestive heart failure, persistent sepsis, and repeat arterial emboli should be treated by early surgical intervention. PMID:3620246

  18. The Admissions Equity Struggle

    ERIC Educational Resources Information Center

    Freedman, Eric

    2012-01-01

    It has been a long, litigious road from Heman Sweatt, an African-American mail carrier who wanted to attend the prestigious, all-White law school at the University of Texas at Austin in 1946, to Abigail Fisher, a White high school student who failed to win undergraduate admission to the same university a half-century later. Depending on what the…

  19. 46 CFR 105.10-20 - Pressure vacuum relief valve.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in...

  20. 46 CFR 105.10-20 - Pressure vacuum relief valve.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in...

  1. 46 CFR 105.10-20 - Pressure vacuum relief valve.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in...

  2. 46 CFR 105.10-20 - Pressure vacuum relief valve.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in...

  3. 46 CFR 105.10-20 - Pressure vacuum relief valve.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in...

  4. Rotary pneumatic valve

    DOEpatents

    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.

  5. Liquid rocket valve components

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A monograph on valves for use with liquid rocket propellant engines is presented. The configurations of the various types of valves are described and illustrated. Design criteria and recommended practices for the various valves are explained. Tables of data are included to show the chief features of valve components in use on operational vehicles.

  6. Remote actuated valve implant

    DOEpatents

    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.

  7. Microfluidic sieve valves

    DOEpatents

    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.

  8. Dual stage check valve

    NASA Technical Reports Server (NTRS)

    Whitten, D. E. (Inventor)

    1973-01-01

    A dual stage seat valve head arrangement is described which consists of a primary sealing point located between a fixed orifice seat and a valve poppet, and a secondary sealing point between an orifice poppet and a valve poppet. Upstream of the valve orifice is a flexible, convoluted metal diaphragm attached to the orifice poppet. Downstream of the valve orifice, a finger spring exerts a force against the valve poppet, tending to keep the valve in a closed position. The series arrangement of a double seat and poppet is able to tolerate small particle contamination while minimizing chatter by controlling throttling or metering across the secondary seat, thus preserving the primary sealing surface.

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

    PubMed Central

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

    2016-01-01

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

  10. Admissions Criteria in Teacher Education.

    ERIC Educational Resources Information Center

    Schwanke, Dean

    1981-01-01

    A review of the literature on the topic of admissions criteria in teacher education is presented. Bibliographic annotations review surveys, studies, models, and guidelines on various aspects of admissions criteria, as well as attracting and retaining quality students. (JN)

  11. Vacuum breaker valve assembly

    DOEpatents

    Thompson, Jeffrey L.; Upton, Hubert Allen

    1999-04-27

    Breaker valve assemblies for a simplified boiling water nuclear reactor are described. The breaker valve assembly, in one form, includes a valve body and a breaker valve. The valve body includes an interior chamber, and an inlet passage extends from the chamber and through an inlet opening to facilitate transporting particles from outside of the valve body to the interior chamber. The breaker valve is positioned in the chamber and is configured to substantially seal the inlet opening. Particularly, the breaker valve includes a disk which is sized to cover the inlet opening. The disk is movably coupled to the valve body and is configured to move substantially concentrically with respect to the valve opening between a first position, where the disk completely covers the inlet opening, and a second position, where the disk does not completely cover the inlet opening.

  12. Scissor thrust valve actuator

    DOEpatents

    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.

  13. Heart valve surgery - series (image)

    MedlinePlus

    There are four valves in the heart: aortic valve, mitral valve, tricuspid valve, and pulmonary valve. The valves are designed to control the direction of blood flow through the heart. The opening and closing of the heart valves produce the heart-beat sounds.

  14. Magnetically operated check valve

    NASA Astrophysics Data System (ADS)

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

    1993-03-01

    A magnetically operated check valve is disclosed having, in one aspect, 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.

  15. Valve actuating mechanism for internal combustion engine

    SciTech Connect

    Kuroda, Y.

    1987-01-20

    This patent describes an internal combustion engine comprising a cylinder having a bore, a cylinder head fixed relative to the cylinder, and three poppet type valves supported by the cylinder head for reciprocation about respective axes all positioned on the same side of a plane containing the axis of the cylinder bore. It also comprises a single camshaft having three respective cam lobes each associated with a respective of the valves, the camshaft being rotatable about an axis extending parallel to the plane and lying on the same side thereof as the valve axes. A rocker arms means is associated with one of the cam lobes for operating its associated valve, and means is included for directly operating the remainder of the valves from the remaining cam lobes.

  16. When a Heart Murmur Signals Valve Disease

    MedlinePlus

    ... Problem: Valve Stenosis - Problem: Aortic Valve Stenosis - Problem: Mitral Valve Stenosis - Problem: Tricuspid Valve Stenosis - Problem: Pulmonary Valve Stenosis Problem: Mitral Valve Prolapse Problem: Heart Valve Regurgitation - Problem: Aortic ...

  17. Valve actuating mechanism for internal combustion engine

    SciTech Connect

    Tsuchida, N.

    1986-06-03

    A valve train for an internal combustion engine is described having a cylinder head assembly, a first poppet valve supported by the cylinder head assembly for reciprocation along an axis defined by its stem, a second poppet valve supported by the cylinder head assembly for reciprocation along an axis defined by its stem, a camshaft supported by the cylinder head assembly for rotation about a rotational axis intersected by the first poppet valve stem axis, cam means on the camshaft, a tappet slidably supported by the cylinder head assembly and associated with the cam means and the first valve for opening directly the first valve, a rocker arm supported for pivotal movement and associated with the cam means for pivoting the rocker arm, and means on the rocker arm operative to actuate the second valve upon pivotal movement of the rocker arm. The improvement described here consists of the rocker arm being pivotally supported by a rocker arm shaft carried by the cylinder head assembly and lubricant passage means extending through the cylinder head assembly and through the rocker arm shaft for lubricating the pivotal support for the rocker arm and the sliding support for the tappet.

  18. Recirculating valve lash adjuster

    SciTech Connect

    Stoody, R.R.

    1987-02-24

    This patent describes an internal combustion engine with a valve assembly of the type including overhead valves supported by a cylinder head for opening and closing movements in a substantially vertical direction and a rotatable overhead camshaft thereabove lubricated by engine oil pumped by an engine oil pump. A hydraulic lash adjuster with an internal reservoir therein is solely supplied with run-off lubricating oil from the camshaft which oil is pumped into the internal reservoir of the lash adjuster by self-pumping operation of the lash adjuster produced by lateral forces thereon by the rotative operation of the camshaft comprising: a housing of the lash adjuster including an axially extending bore therethrough with a lower wall means of the housing closing the lower end thereof; a first plunger member being closely slidably received in the bore of the housing and having wall means defining a fluid filled power chamber with the lower wall means of the housing; and a second plunger member of the lash adjuster having a portion being loosely slidably received and extending into the bore of the housing for reciprocation therein. Another portion extends upwardly from the housing to operatively receive alternating side-to-side force inputs from operation of the camshaft.

  19. Valve-in-Valve Transcatheter Valve Implantation in the Non-Aortic Position

    PubMed Central

    Ranney, David N.; Williams, Judson B.; Wang, Andrew; Gaca, Jeffrey G.

    2016-01-01

    Background Transcatheter valve-in-valve (VIV) procedures are an alternative to standard surgical valve replacement in high risk patients. Methods Cases in which a commercially approved transcatheter aortic valve replacement (TAVR) device was used for a non-aortic VIV procedure between November 2013 and September 2015 are reviewed. Clinical, echocardiographic, and procedural details, patient survival, and symptom severity by NYHA class at follow-up were assessed. Results All patients were heart-team determined high-risk for conventional redo surgery (mean STS PROM = 6.8 ± 2.2%). Five patients underwent VIV replacement in the non-aortic position, 4 for bioprosthetic mitral valve dysfunction and one for bioprosthetic tricuspid valve dysfunction. Bioprosthetic failure was due to stenosis in 3 patients and regurgitation in 2 others. A balloon-expandable device was used for all patients (Edwards Lifesciences, Irvine, CA). Transcatheter VIV replacement was accomplished by the transapical (mitral) and transfemoral venous (tricuspid) approaches. Median post-operative length of stay was 5 days (range 3-12). No deaths occurred at a mean follow-up of 21 months. NYHA class at follow-up decreased from class IV at baseline to class I or II for all patients. No paravalvular leaks greater than trivial were encountered. Median mean gradient following mitral replacement was 6.5 mmHg (range 6-13 mmHg), and following tricuspid replacement was 4 mmHg. Post-operative complications included hematuria, epistaxis, acute kidney injury, and atrial fibrillation. Conclusions Transcatheter VIV implantation in the non-aortic position for dysfunctional bioprostheses can be performed safely with favorable clinical outcomes using a balloon expandable TAVR device. PMID:27059552

  20. Non-collinear valve actuator

    NASA Technical Reports Server (NTRS)

    Richard, James A. (Inventor)

    2012-01-01

    A non-collinear valve actuator includes a primary actuating system and a return spring system with each applying forces to a linkage system in order to regulate the flow of a quarter-turn valve. The primary actuating system and return spring system are positioned non-collinearly, which simply means the primary actuating system and return spring system are not in line with each other. By positioning the primary actuating system and return spring system in this manner, the primary actuating system can undergo a larger stroke while the return spring system experiences significantly less displacement. This allows the length of the return spring to be reduced due to the minimization of displacement thereby reducing the weight of the return spring system. By allowing the primary actuating system to undergo longer strokes, the weight of the primary actuating system may also be reduced. Accordingly, the weight of the non-collinear valve actuator is reduced.

  1. Fast acting check valve

    NASA Technical Reports Server (NTRS)

    Perkins, Gerald S. (Inventor)

    1979-01-01

    A check valve which closes more rapidly to prevent wearing of the valve seat and of the valve member that seals thereagainst, including a solenoid or other actuator that aids the normal spring to quickly close the valve at approximately the time when downpath fluid flow would stop, the actuator then being deenergized. The control circuit that operates the actuator can include a pair of pressure sensors sensing pressure both upstream and downstream from the valve seat. Where the valve is utilized to control flow to or from a piston pump, energization of the actuator can be controlled by sensing when the pump piston reaches its extreme of travel.

  2. Quickly Removable Valve

    NASA Technical Reports Server (NTRS)

    Robbins, John S.

    1988-01-01

    Unit removed with minimal disturbance. Valve inlet and outlet ports adjacent to each other on same side of valve body. Ports inserted into special manifold on fluid line. Valve body attached to manifold by four bolts or, alternatively, by toggle clamps. Electromechanical actuator moves in direction parallel to fluid line to open and close valve. When necessary to clean valve, removed simply by opening bolts or toggle clamps. No need to move or separate ports of fluid line. Valve useful where disturbance of fluid line detrimental or where fast maintenance essential - in oil and chemical industries, automotive vehicles, aircraft, and powerplants.

  3. Ball valve extractor

    DOEpatents

    Herndon, Charles; Brown, Roger A.

    2002-01-01

    An apparatus and process for removing a ball valve is provided. The ball valve removal tool provides a handle sliding along the length of a shaft. One end of the shaft is secured within an interior cavity of a ball valve while the opposite end of the shaft defines a stop member. By providing a manual sliding force to the handle, the handle impacts the stop member and transmits the force to the ball valve. The direction of the force is along the shaft of the removal tool and disengages the ball valve from the ball valve housing.

  4. Living with Heart Valve Disease

    MedlinePlus

    ... page from the NHLBI on Twitter. Living With Heart Valve Disease Heart valve disease is a lifelong condition. However, ... all of your medicines as prescribed. Pregnancy and Heart Valve Disease Mild or moderate heart valve disease during pregnancy ...

  5. Valve operating mechanism for internal combustion engine

    SciTech Connect

    Fujii, N.; Iwata, T.; Takahara, N.

    1988-12-27

    This patent describes a valve operating mechanism in an internal combustion engine comprising: a single camshaft rotatably disposed above the cylinder head, a single rocker arm shaft rotatably disposed above the cylinder head; an intake-valve rocker arm swingably supported on the rocker arm shaft and operatively engaging the intake valve; an exhaust-valve rocker arm swingably supported on the rocker arm shaft and operatively engaging the exhaust valve, a camshaft holder disposed above the cylinder bore, the camshaft being rotatably supported by the camshaft holder; a rocker arms shaft holder disposed above the cylinder bore, the rocker arm shaft being rotatably supported by the rocker arm shaft holder; and a plug insertion tube having a plug insertion hole for insertion of the spark plug therethrough, the plug insertion tube being integrally formed with the camshaft holder and the rocker arm shaft holder in a holder block means.

  6. Fuel control valve construction, parts therefor and methods

    SciTech Connect

    Kelly, S.T.; Katchka, J.R.

    1990-05-29

    This patent describes a fuel control valve construction. It comprises: a housing means having an inlet means adapted to be interconnected to a main burner means, the housing means having a main valve seat for interconnecting the inlet means with the main outlet means, the housing means having a movable main valve member for opening and closing the main valve seat, the housing means having a movable lever carrying the main valve member and having a manually operable actuator means for controlling the operating positions of the lever, the lever having an intermediate cam follower portion and opposed ends disposed on each side of the cam follower portion with one end of the opposed ends being pivotally mounted to the housing means and with the other end of the opposed ends carrying the main valve member, the housing means having biasing means operatively interconnected to the lever to tend to pivot the lever in one direction that opens the main valve member away from its main valve seat.

  7. [Influence of pivot distance on the performance of a mechanic heart valve].

    PubMed

    Zhang, Yong; Wu, Liangliang; Huang, Nan

    2014-10-01

    Based on the analysis of the influence of the valve pivot distance on the performance of mechanical heart valve (MHV), such as the valve opening and closing features, flow field characteristics and the valve assembly properties, value constraints of the valve pivot distance were established, and the reasonable valve was obtained by means of the finite element method. It can be shown that the central flow characteristics of the valve could be enhanced with the increasing of the ratio of pivot distance to valve inner diameter, but the plastic deformation of the ring could be liable to occur in the MHV assembly process. It is proved that the valve of specifications can be designed in similar ratio of pivot distance to valve inner diameter according to the result of the valve performance experiment.

  8. Late follow-up of the Braunwald-Cutter valve.

    PubMed

    Jonas, R A; Garratt-Boyes, B G; Kerr, A R; Whitlock, R M

    1982-06-01

    A retrospective review has been made of 234 patients who received 239 Braunwald-Cutter valves (109 aortic, 130 mitral). For the aortic valve, the thromboembolic rate was very high (10.3 per 100 patient-years). This was associated with severe strut cloth wear in 94.5% of valves and with long strands of fibrin attached to the worn cloth in 58% of valves studied at reoperation or postmortem examination. The aortic poppet showed a mean decrease in volume of 4%, and poppet escape was recognized in 4 patients. The actuarial incidence of poppet escape was less than that predicted in earlier reports. There was a 4% incidence of stenosis of the valve. The hospital mortality associated with removal of the aortic Braunwald-Cutter valve and replacement with another device was 4%. Performance of the mitral Braunwald-Cutter valve appears satisfactory to date (mean follow-up, 42 months). Its electric removal is not recommended.

  9. Problem: Mitral Valve Regurgitation

    MedlinePlus

    ... Options • Recovery and Healthy Living Goals • Personal Stories Heart Valve Disease Symptoms Dr. Robert Bonow describes the symptoms that may alert you to heart valve disease. Support Network: You're Not Alone Popular Articles ...

  10. Problem: Heart Valve Regurgitation

    MedlinePlus

    ... Options • Recovery and Healthy Living Goals • Personal Stories Heart Valve Disease Symptoms Dr. Robert Bonow describes the symptoms that may alert you to heart valve disease. Support Network: You're Not Alone Popular Articles ...

  11. Aortic Valve Disease

    MedlinePlus

    ... Ventricle Normal Heart Select Disease To Learn More Aortic Stenosis Aortic Insufficiency Aorta The aorta is the main ... the rest of your body. Aortic Valve In aortic stenosis, the aortic valve becomes narrowed and does not ...

  12. Aortic Valve Stenosis

    MedlinePlus

    ... By Mayo Clinic Staff Aortic valve stenosis — or aortic stenosis — occurs when the heart's aortic valve narrows. This ... pressure may prevent or slow the development of aortic stenosis. Ask your doctor if you need to lower ...

  13. Valve actuator for internal combustion engine

    SciTech Connect

    Uchida, T.

    1987-06-16

    A valve actuating mechanism is described for an overhead valve and overhead cam type internal combustion engine in which the camshaft is positioned above and between the valve and a cam follower seat member in a cylinder head of the engine. The cam follower seat member is threadedly mounted in the cylinder head and has a semi-spherical recess facing upwardly. A cam follower has an adjustable bolt threadedly received in one end of the cam follower. The adjustable bolt has a spherical fulcrum engaging the semispherical recess of the seat member. The cam follower also has a downwardly facing means on the other end for engaging the valve and an upwardly facing slipper face for sliding engagement with a cam on the camshaft. The cam is adapted to rotate across the slipper face in the direction of the valve. The slipper face has a surface shape for engaging the cam at the start of valve-lifting movement of the cam follower at a point through which a line tangent to the slipper face is substantially parallel to a line through contact points between the cam follower. The seat member and valve for minimizing the lateral forces are imposed on the cam follower by the cam at the start of the valve-lifting movement.

  14. Corynebacterium CDC Group G Native and Prosthetic Valve Endocarditis.

    PubMed

    Sattar, Adil; Yu, Siegfried; Koirala, Janak

    2015-08-11

    We report the first case of native and recurrent prosthetic valve endocarditis with Corynebacterium CDC group G, a rarely reported cause of infective endocarditis (IE). Previously, there have been only two cases reported for prosthetic valve IE caused by these organisms. A 69-year-old female with a known history of mitral valve regurgitation presented with a 3-day history of high-grade fever, pleuritic chest pain and cough. Echocardiography confirmed findings of mitral valve thickening consistent with endocarditis, which subsequently progressed to become large and mobile vegetations. Both sets of blood cultures taken on admission were positive for Corynebacterium CDC group G. Despite removal of a long-term venous access port, the patient's presumed source of line associated bacteremia, mitral valve replacement, and aggressive antibiotic therapy, the patient had recurrence of vegetations on the prosthetic valve. She underwent replacement of her prosthetic mitral valve in the subsequent 2 weeks, before she progressed to disseminated intravascular coagulation and expired. Although they are typically considered contaminants, corynebacteria, in the appropriate clinical setting, should be recognized, identified, and treated as potentially life-threatening infections, particularly in the case of line-associated bacteremias, and native and prosthetic valve endocarditis.

  15. Case Report: Prothesis-patient mismatch after aortic valve replacement.

    PubMed

    Rodriguez-Ospina, Luis; Garcia-Morell, Juan; Rodriguez-Monserrate, Carla P; Valentin-Nieves, Julio

    2015-01-01

    Valve replacement is the standard surgical treatment of diseased valves that cannot be repaired. The main goal of replacement is to exchange the diseased valve with one that has the engineering and hemodynamics as close as possible to the disease free native valve. However due to mechanical and fluid dynamic constraints all prosthetic heart valves (PHVs) are smaller than normal and thus are inherently stenotic. This represents a challenge when it comes time to replace a valve. The correct valve with the correct and matching profile has to be selected before the procedure to avoid possible complications. It is well recognized that patients are also prone to patient-prosthesis mismatch at long term which could have consequences in the clinical outcomes (1). The evaluation of patient-prosthesis mismatch (PPM) has not been sufficiently emphasized in common practice. Failure to recognize this fact may lead to significant hemodynamic impairment and worsening of the clinical status over the time. Making efforts to identifying patients at risk may decrease the prevalence of PPM, the economic impact to our health system, the morbidity and mortality involved in these cases as well as creates efforts to standardized pre-operative protocols to minimized risk of PPM. We present a case of a 78 years old male patient who underwent aortic valve replacement due severe aortic stenosis, afterwards his clinical course got complicated with several admissions for shortness of breath and decompensated congestive heart failure (CHF).

  16. Stemless Ball Valve

    NASA Technical Reports Server (NTRS)

    Burgess, Robert K.; Yakos, David; Walthall, Bryan

    2012-01-01

    This invention utilizes a new method of opening and closing a ball valve. Instead of rotating the ball with a perpendicular stem (as is the case with standard ball valves), the ball is rotated around a fixed axis by two guide pins. This innovation eliminates the leak point that is present in all standard ball valves due to the penetration of an actuation stem through the valve body. The VOST (Venturi Off-Set-Technology) valve has been developed for commercial applications. The standard version of the valve consists of an off-set venturi flow path through the valve. This path is split at the narrowest portion of the venturi, allowing the section upstream from the venturi to be rotated. As this rotation takes place, the venturi becomes restricted as one face rotates with respect to the other, eventually closing off the flow path. A spring-loaded seal made of resilient material is embedded in the upstream face of the valve, making a leak-proof seal between the faces; thus a valve is formed. The spring-loaded lip seal is the only seal that can provide a class six, or bubble-tight, seal against the opposite face of the valve. Tearing action of the seal by high-velocity gas on this early design required relocation of the seal to the downstream face of the valve. In the stemless embodiment of this valve, inner and outer magnetic cartridges are employed to transfer mechanical torque from the outside of the valve to the inside without the use of a stem. This eliminates the leak path caused by the valve stems in standard valves because the stems penetrate through the bodies of these valves.

  17. Aerodynamic Shutoff Valve

    NASA Technical Reports Server (NTRS)

    Horstman, Raymond H.

    1992-01-01

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

  18. Valve technology: A compilation

    NASA Technical Reports Server (NTRS)

    1971-01-01

    A technical compilation on the types, applications and modifications to certain valves is presented. Data cover the following: (1) valves that feature automatic response to stimuli (thermal, electrical, fluid pressure, etc.), (2) modified valves changed by redesign of components to increase initial design effectiveness or give the item versatility beyond its basic design capability, and (3) special purpose valves with limited application as presented, but lending themselves to other uses with minor changes.

  19. Heart Valve Diseases

    MedlinePlus

    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 ...

  20. Mitral Valve Prolapse

    PubMed Central

    Rosser, Walter W.

    1992-01-01

    The author discusses the pathophysiology of mitral valve prolapse and provides guidelines to identify and treat low-to high-risk mitral valve prolapse. An approach to diagnosing bacterial endocarditis and its prophylaxis are also discussed. The author reviews mitral valve prolapse syndrome and the risk of sudden death.

  1. Double-Poppet Valve

    NASA Technical Reports Server (NTRS)

    Huber, W. C.

    1984-01-01

    New valve design includes two poppet/seat combinations actuated simultaneously. If one fails, other continues to seal against fluid flow. Valve primarily useful for handling dangerous fluids and lighter and more compact than comparable redundant-valve systems used at present.

  2. Liquid rocket valve assemblies

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The design and operating characteristics of valve assemblies used in liquid propellant rocket engines are discussed. The subjects considered are as follows: (1) valve selection parameters, (2) major design aspects, (3) design integration of valve subassemblies, and (4) assembly of components and functional tests. Information is provided on engine, stage, and spacecraft checkout procedures.

  3. Well safety valve

    SciTech Connect

    Vinzant, M.B.; Hilts, R.L.; Meaders, M.; Speegle, S.C.

    1984-07-24

    A retrievable well safety valve in a cased well system including a tubing string, a dual packer downhole around the tubing sealing with the casing and submersible pump in the tubing string below the packer. The safety valve controls flow of pumped fluids through the tubing to surface and directs gas flow into the casing annulus above the packer. When the safety valve is landed in cooperating tubing nipples above the packer, separated central annular flow passages are formed for pumped fluids and gas respectively. A ball valve in the central flow passage controls pumped fluid flow therethrough and an annular valve coupled to the ball valve controls gas flow from below the packer through the annular flow passage around and by the ball valve. When the ball valve is in the down and open position, the valve ball member engages a lower seat, which maintains the central and annular flow passages separate and prevents comingling flow of fluids and gas. The coupled valves are held open by pressured fluid from surface and are closed automatically on loss of pressure in their control fluid circuits. When the valves close, a circuit of flow passages for recirculating pumped fluids and gas are opened below the ball valve and the pump may continue operation without overload.

  4. Microblower assisted barometric valve

    DOEpatents

    Rossabi, Joseph; Hyde, Warren K.; Riha, Brian D.; Jackson, Dennis G.; Sappington, Frank

    2005-12-06

    A gas exchange apparatus is provided which provides for both passive fluid flow and blower associated fluid flow through a barometric valve. A battery powered blower is provided which allows for operation of the barometric valve during times when the barometric valve would otherwise be closed, and provides for enhanced volume of gas exchange.

  5. Lock For Valve Stem

    NASA Technical Reports Server (NTRS)

    Burley, Richard K.; Guirguis, Kamal S.

    1991-01-01

    Simple, cheap device locks valve stem so its setting cannot be changed by unauthorized people. Device covers valve stem; cover locked in place with standard padlock. Valve lock made of PVC pipe and packing band. Shears, drill or punch, and forming rod only tools needed.

  6. How Is Mitral Valve Prolapse Treated?

    MedlinePlus

    ... page from the NHLBI on Twitter. How Is Mitral Valve Prolapse Treated? Most people who have mitral valve ... all hospitals offer this method. Valve Repair and Valve Replacement In mitral valve surgery, the valve is repaired or replaced. ...

  7. Engine valve actuation for combustion enhancement

    DOEpatents

    Reitz, Rolf Deneys; Rutland, Christopher J.; Jhavar, Rahul

    2008-03-04

    A combustion chamber valve, such as an intake valve or an exhaust valve, is briefly opened during the compression and/or power strokes of a 4-strokes combustion cycle in an internal combustion engine (in particular, a diesel or CI engine). The brief opening may (1) enhance mixing withing the combustion chamber, allowing more complete oxidation of particulates to decrease engine emissions; and/or may (2) delay ignition until a more desirable time, potentially allowing a means of timing ignition in otherwise difficult-to-control conditions, e.g., in HCCI (Homogeneous Charge Compression Ignition) conditions.

  8. Engine Valve Actuation For Combustion Enhancement

    DOEpatents

    Reitz, Rolf Deneys; Rutland, Christopher J.; Jhavar, Rahul

    2004-05-18

    A combustion chamber valve, such as an intake valve or an exhaust valve, is briefly opened during the compression and/or power strokes of a 4-stroke combustion cycle in an internal combustion engine (in particular, a diesel or CI engine). The brief opening may (1) enhance mixing withing the combustion chamber, allowing more complete oxidation of particulates to decrease engine emissions; and/or may (2) delay ignition until a more desirable time, potentially allowing a means of timing ignition in otherwise difficult-to-control conditions, e.g., in HCCI (Homogeneous Charge Compression Ignition) conditions.

  9. Valve Cap For An Electric Storage Cell

    DOEpatents

    Verhoog, Roelof; Genton, Alain

    2000-04-18

    The valve cap for an electric storage cell includes a central annular valve seat (23) and a membrane (5) fixed by its peripheral edge and urged against the seat by a piston (10) bearing thereagainst by means of a spring (12), the rear end of said spring (12) bearing on the endwall (8) of a chamber (20) formed in the cap and containing the piston (10) and the spring. A vent (19) puts the chamber (20) into communication with the atmosphere. A central orifice (26, 28) through the piston (10) and the membrane (5), enables gas from within the cell to escape via the top vent (19) when the valve opens.

  10. Main Oxidizer Valve Design

    NASA Technical Reports Server (NTRS)

    Addona, Brad; Eddleman, David

    2015-01-01

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

  11. Valve control system for internal combustion engines

    SciTech Connect

    Kaptur, S.J.

    1989-10-24

    This patent describes a valve control system for an internal combustion engine. The system comprising a primary control and a secondary control for modifying the operation of the primary control. The primary control comprising: a camshaft journaled for rotation in camshaft brackets, intake and exhaust cylindrical cams including cam channels; valve pin means; and timing belt means. The secondary system comprising: control plate means adjustably mounted between the cylindrical cams, rocker arm means; and at least one driver positioned between the driver leg and one of cylindrical cams.

  12. The Changing College Admissions Scene.

    ERIC Educational Resources Information Center

    Sjogren, Cliff

    1983-01-01

    Discusses the status of college admissions and some of the forces that influenced college admissions policies during each of four three-year periods: the Sputnik Era (1957-60), the Postwar Baby Boom Era (1964-67), the "New Groups" Era (1971-74), and the Stable Enrollment Era (1978-81). (PGD)

  13. Optimal Admission to Higher Education

    ERIC Educational Resources Information Center

    Albaek, Karsten

    2017-01-01

    This paper analyses admission decisions when students from different high school tracks apply for admission to university programmes. I derive a criterion that is optimal in the sense that it maximizes the graduation rates of the university programmes. The paper contains an empirical analysis that documents the relevance of theory and illustrates…

  14. Thermostatic Radiator Valve Evaluation

    SciTech Connect

    Dentz, J.; Ansanelli, E.

    2015-01-01

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

  15. 46 CFR 45.155 - Inlets and discharge piping: Valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... means for closing at the shell if the controls are readily accessible and have indicators showing when... have— (1) An automatic nonreturn valve with a positive means for closing; or (2) Two automatic... show when the valve is not closed. (c) If the pipe discharges from a space that is not manned or...

  16. 46 CFR 45.155 - Inlets and discharge piping: Valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... means for closing at the shell if the controls are readily accessible and have indicators showing when... have— (1) An automatic nonreturn valve with a positive means for closing; or (2) Two automatic... show when the valve is not closed. (c) If the pipe discharges from a space that is not manned or...

  17. 46 CFR 45.155 - Inlets and discharge piping: Valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... means for closing at the shell if the controls are readily accessible and have indicators showing when... have— (1) An automatic nonreturn valve with a positive means for closing; or (2) Two automatic... show when the valve is not closed. (c) If the pipe discharges from a space that is not manned or...

  18. Valve selection in aortic valve endocarditis

    PubMed Central

    Zubrytska, Yana

    2016-01-01

    Aortic prosthetic valve endocarditis (PVE) is a potentially life-threatening disease. Mortality and incidence of infective endocarditis have been reduced in the past 30 years. Medical treatment of aortic PVE may be successful in patients who have a prompt response after antibiotic treatment and who do not have prosthetic dysfunction. In advanced stages, antibiotic therapy alone is insufficient to control the disease, and surgical intervention is necessary. Surgical treatment may be lifesaving, but it is still associated with considerable morbidity and mortality. The aim of surgery is to perform a radical excision of all infected and necrotic tissue, reconstruction of the left ventricle outflow tract, and replacement of the aortic valve. There is no unanimous consensus on which is the optimal prosthesis to implant in this context, and several surgical techniques have been suggested. We aim to analyze the efficacy of the surgical treatment and discuss the issue of valve selection in patients with aortic valve endocarditis. PMID:27785132

  19. Guide to prosthetic cardiac valves

    SciTech Connect

    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.

  20. What Is Heart Valve Disease?

    MedlinePlus

    ... flow properly. Acquired heart valve disease usually involves aortic or mitral valves. Although the valves are normal at first, problems develop over time. Both congenital and acquired heart valve disease can cause stenosis or backflow. Outlook Many people have heart valve ...

  1. Valve train for internal combustion engine

    SciTech Connect

    Honda, S.; Ishida, Y.; Kanbe, T.

    1988-04-26

    A valve train for an internal combustion engine, the internal combustion engine including a cylinder head having a pair of intake and exhaust ports, the valve train is described comprising: (a) a camshaft housing adapted to be mounted on the cylinder head to define a camshaft chamber; (b) a pair of intake and exhaust valves mounted on the cylinder head so as to be moveable for closing and opening the intake and exhaust ports respectively; (c) mounting means on the cylinder head disposed within the camshaft; (d) a camshaft mounted within the camshaft chamber for rotation about an axis thereof and disposed between the cylinder head and the mounting means; (e) a pair of elongated rocker arms interposed between the camshaft and the mounting means; and (f) a pair of hydraulic tappets mounted on the mounting means.

  2. Cryogenic Cam Butterfly Valve

    NASA Technical Reports Server (NTRS)

    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.

  3. Minimally invasive valve surgery.

    PubMed

    Woo, Y Joseph; Seeburger, Joerg; Mohr, Friedrich W

    2007-01-01

    As alternatives to standard sternotomy, surgeons have developed innovative, minimally invasive approaches to conducting valve surgery. Through very small skin incisions and partial upper sternal division for aortic valve surgery and right minithoracotomy for mitral surgery, surgeons have become adept at performing complex valve procedures. Beyond cosmetic appeal, apparent benefits range from decreased pain and bleeding to improved respiratory function and recovery time. The large retrospective studies and few small prospective randomized studies are herein briefly summarized. The focus is then directed toward describing specific intraoperative technical details in current clinical use, covering anesthetic preparation, incision, mediastinal access, cardiovascular cannulation, valve exposure, and valve reconstruction. Finally, unique situations such as pulmonic valve surgery, reoperations, beating heart surgery, and robotics are discussed.

  4. Intelligent Flow Control Valve

    NASA Technical Reports Server (NTRS)

    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.

  5. JenaValve.

    PubMed

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

    2012-09-01

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

  6. Assisted living nursing practice: admission assessment.

    PubMed

    Mitty, Ethel; Flores, Sandi

    2007-01-01

    Admission assessment, generally conducted by a registered nurse, is autonomous, without opportunity for dialogue with colleagues and other health care professionals and bounded by the nurse's knowledge and skills, state regulations, facility practices, and marketing. The fact that some states permit admission and retention of nursing home level-of-care residents and provision of end-of-life care means that the assessment has to be able to predict the resident's likely trajectory of well-being as well as chronic illness exacerbation. The nurse must have a clear perspective on staff competencies and judge whether additional education or training will be necessary. This article reviews assessment standards of practice as put forth by the American Assisted Living Nurses Association as part of its application for recognition of assisted living nursing as specialty nursing practice by the American Nurses Association. The role of the Licensed Practical Nurse/Licensed Vocational Nurse in resident assessment is also discussed.

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

    ClinicalTrials.gov

    2016-03-09

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

  8. [Modern mitral valve surgery].

    PubMed

    Bothe, W; Beyersdorf, F

    2016-04-01

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

  9. Passively actuated valve

    SciTech Connect

    Modro, S. Michael; Ougouag, Abderrafi M.

    2005-09-20

    A passively actuated valve for isolating a high pressure zone from a low pressure zone and discontinuing the isolation when the pressure in the high pressure zone drops below a preset threshold. If the pressure in the high pressure zone drops below the preset threshold, the valve opens and allows flow from the high pressure zone to the low pressure zone. The valve remains open allowing pressure equalization and back-flow should a pressure inversion between the two pressure zone occur.

  10. 28 CFR 549.42 - Involuntary admission.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SERVICES Administrative Safeguards for Psychiatric Treatment and Medication § 549.42 Involuntary admission... voluntarily consent either to psychiatric admission or to medication, is subject to judicial...

  11. 32 CFR 242.5 - Admission procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... HEALTH SCIENCES § 242.5 Admission procedures. (a) Application—(1) Civilians. Civilians seeking admission to the School of Medicine shall make direct application following instructions published in...

  12. Frostless heat pump having thermal expansion valves

    DOEpatents

    Chen, Fang C [Knoxville, TN; Mei, Viung C [Oak Ridge, TN

    2002-10-22

    A heat pump system having an operable relationship for transferring heat between an exterior atmosphere and an interior atmosphere via a fluid refrigerant and further having a compressor, an interior heat exchanger, an exterior heat exchanger, a heat pump reversing valve, an accumulator, a thermal expansion valve having a remote sensing bulb disposed in heat transferable contact with the refrigerant piping section between said accumulator and said reversing valve, an outdoor temperature sensor, and a first means for heating said remote sensing bulb in response to said outdoor temperature sensor thereby opening said thermal expansion valve to raise suction pressure in order to mitigate defrosting of said exterior heat exchanger wherein said heat pump continues to operate in a heating mode.

  13. Transventricular mitral valve operations.

    PubMed

    Joseph Woo, Y; McCormick, Ryan C

    2011-10-01

    We report transventricular mitral valve operations in 2 patients with severe mitral regurgitation and postinfarction left ventricular rupture and pseudoaneurysm. The first patient had direct papillary muscle involvement necessitating replacement of the mitral valve. The second patient had indirect mitral involvement allowing for placement of an atrial mitral annuloplasty ring via the left ventricle. Both patients showed no mitral valve regurgitation after replacement or repair and had uneventful postoperative recoveries. These cases demonstrate a feasible, alternative, transventricular approach to mitral valve replacement and repair.

  14. Magnetic Check Valve

    NASA Technical Reports Server (NTRS)

    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.

  15. Solid handling valve

    DOEpatents

    Williams, William R.

    1979-01-01

    The present invention is directed to a solids handling valve for use in combination with lock hoppers utilized for conveying pulverized coal to a coal gasifier. The valve comprises a fluid-actuated flow control piston disposed within a housing and provided with a tapered primary seal having a recessed seat on the housing and a radially expandable fluid-actuated secondary seal. The valve seals are highly resistive to corrosion, erosion and abrasion by the solids, liquids, and gases associated with the gasification process so as to minimize valve failure.

  16. Engine valve driving apparatus

    SciTech Connect

    Masuda, S.; Uesugi, T.; Oda, H.

    1989-01-03

    An engine valve driving apparatus for an internal combustion engine having a cam driven engine valve is described. It consists of a camshaft rotatable in synchronism with rotation of a crankshaft of an engine and a movable cam member supported by the camshaft for axial movement and prevented from turning relative to the camshaft. The movable cam member can be axially shifted between an operative position wherein the cam member is cooperative with a member of the engine valve so as to cause an operation of the engine valve and an inoperative position wherein the cam member is out of cooperation with the member.

  17. Modeling the Mitral Valve

    NASA Astrophysics Data System (ADS)

    Kaiser, Alexander

    2016-11-01

    The mitral valve is one of four valves in the human heart. The valve opens to allow oxygenated blood from the lungs to fill the left ventricle, and closes when the ventricle contracts to prevent backflow. The valve is composed of two fibrous leaflets which hang from a ring. These leaflets are supported like a parachute by a system of strings called chordae tendineae. In this talk, I will describe a new computational model of the mitral valve. To generate geometry, general information comes from classical anatomy texts and the author's dissection of porcine hearts. An MRI image of a human heart is used to locate the tips of the papillary muscles, which anchor the chordae tendineae, in relation to the mitral ring. The initial configurations of the valve leaflets and chordae tendineae are found by solving solving an equilibrium elasticity problem. The valve is then simulated in fluid (blood) using the immersed boundary method over multiple heart cycles in a model valve tester. We aim to identify features and mechanisms that influence or control valve function. Support from National Science Foundation, Graduate Research Fellowship Program, Grant DGE 1342536.

  18. What Causes Heart Valve Disease?

    MedlinePlus

    ... page from the NHLBI on Twitter. What Causes Heart Valve Disease? Heart conditions and other disorders, age-related changes, ... valve disease. Other Conditions and Factors Linked to Heart Valve Disease Many other conditions and factors are linked to ...

  19. Options for Heart Valve Replacement

    MedlinePlus

    ... which may include human or animal donor tissue) Ross Procedure — “Borrowing” your healthy valve and moving it ... Considerations for Surgery Medications Valve Repair Valve Replacement - Ross Procedure - Newer Surgery Options - What is TAVR? - Types ...

  20. Native valve endocarditis due to Pichia ohmeri.

    PubMed

    João, Isabel; Duarte, José; Cotrim, Carlos; Rodrigues, Ana; Martins, Cristina; Fazendas, Paula; Oliveira, L Moura; Diogo, José; Carrageta, Manuel

    2002-09-01

    Candida species can cause clinical manifestations in various organs of the cardiovascular system, i.e., the pericardium, myocardium, and endocardium, with endocarditis being the best-known clinical entity. Endocarditis is seen primarily in intravenous drug users and in individuals with damaged native valves, especially in congenital heart disease or rheumatic valvular diseases, and in prosthetic heart valves. The authors present a case of Pichia ohmeri endocarditis in an intravenous drug user, with an unusual presentation form. This is a case of a 42-year-old man, an intravenous heroin user, who was admitted to our Vascular Surgery Department because of fever and acute serious ischemia of the left inferior limb. He presented with fever (39 degrees C), a pale and cold left limb, absence of the left popliteal pulse, and a pansystolic murmur at the cardiac apex. The transthoracic echocardiogram showed a large vegetation on the anterior leaflet of the mitral valve and severe mitral regurgitation with good left ventricular systolic function. Empirical antibiotic therapy was started. Six days after admission, embolectomy was performed with partial clinical recovery. Three blood cultures and the embolus showed a teleomorphic form of Candida guilliermondii - Pichia ohmeri. Therapy with intravenous liposomal amphotericin B, fluocitosin, imipenem, and aztreonam was started. Two weeks later, his clinical condition deteriorated with acute heart failure refractory to medical therapy, mandating mechanical ventilation and high-dose vasopressor and inotropic amine support. He underwent urgent mitral valve replacement with a biologic prosthetic valve. Rapid stabilization of the cardiac status occurred, but ischemic limb lesions required further vascular interventions.

  1. Valve mechanisms for at least two simultaneously actuable valves

    SciTech Connect

    Heimburg, F.

    1989-02-21

    This patent describes a valve gear for at least two valves of an internal combustion engine to be operated simultaneously on longitudinal axes, wherein the valve gear comprises a thrust device which is common to all valves and displaceable on an axis by a cam shaft and against which the valves abut by their valve stems to that displacement of the thrust device causes corresponding displacement of the valves, characterized in that the camshaft includes a single cam that is seated on the thrust device eccentrically relative to its axis causing rotation of the thrust device about its axis. When the thrust device is displaced, the thrust device is axially symmetrical, and the valve stems each abut against the thrust device at positions centered on points offset from the longitudinal axes of the valves causing rotation of the valves about their longitudinal axis when the valves are displaced.

  2. Understanding Heart Valve Problems and Causes

    MedlinePlus

    ... affecting the aortic valve, and can lead to aortic stenosis . Mediastinal radiation therapy (radiation to the chest) – Studies ... Disease "Innocent" Heart Murmur Problem: Valve Stenosis - Problem: Aortic Valve Stenosis - Problem: Mitral Valve Stenosis - Problem: Tricuspid Valve Stenosis - ...

  3. How Is Heart Valve Disease Treated?

    MedlinePlus

    ... 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 ...

  4. Temperature-Operated Valve

    NASA Technical Reports Server (NTRS)

    Morrison, Andrew D.

    1994-01-01

    Bimetallic valve stem positions orifice at end of inner pipe orifice so liquid flows to outlet when temperature lies within small range of preset value. If liquid too cold or too hot, orifices misaligned and liquid returned to source. Such as in shower, valve prevents outflow of dangerously hot or uncomfortably cold water.

  5. Heimlich valve and pneumothorax.

    PubMed

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

    2015-03-01

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

  6. Mitral valve surgery - open

    MedlinePlus

    ... Saunders; 2012:chap 61. Otto CM, Bonow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Mitral Valve Prolapse Browse the Encyclopedia A.D. ...

  7. Minimally invasive valve surgery.

    PubMed

    Woo, Y Joseph

    2009-08-01

    Traditional cardiac valve replacement surgery is being rapidly supplanted by innovative, minimally invasive approaches toward the repair of these valves. Patients are experiencing benefits ranging from less bleeding and pain to faster recovery and greater satisfaction. These operations are proving to be safe, highly effective, and durable, and their use will likely continue to increase and become even more widely applicable.

  8. Linear motion valve

    NASA Technical Reports Server (NTRS)

    Chandler, J. A. (Inventor)

    1985-01-01

    The linear motion valve is described. The valve spool employs magnetically permeable rings, spaced apart axially, which engage a sealing assembly having magnetically permeable pole pieces in magnetic relationship with a magnet. The gap between the ring and the pole pieces is sealed with a ferrofluid. Depletion of the ferrofluid is minimized.

  9. Valve for abrasive material

    DOEpatents

    Gardner, Harold S.

    1982-01-01

    A ball valve assembly for controlling the flow of abrasive particulates including an enlarged section at the bore inlet and an enlarged section at the bore outlet. A refractory ceramic annular deflector is positioned in each of the enlarged sections, substantially extending the useful life of the valve.

  10. Heimlich valve and pneumothorax

    PubMed Central

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

    2015-01-01

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

  11. Space Vehicle Valve System

    NASA Technical Reports Server (NTRS)

    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.

  12. Boston Scientific Lotus valve.

    PubMed

    Meredith, Ian T; Hood, Kristin L; Haratani, Nicole; Allocco, Dominic J; Dawkins, Keith D

    2012-09-01

    As a result of recent randomised controlled trials and registry observations, transcatheter aortic valve replacement (TAVR) enjoys growing appeal for the treatment of patients at high or extreme risk from surgical aortic valve replacement. However, the current technologies and techniques have important limitations, including risk of stroke, vascular complications and paravalvular aortic regurgitation, which may in turn influence survival. While careful patient selection and screening may improve outcomes, new valve designs and iterations are required. The Lotus aortic valve replacement system is a new fully repositionable device designed to facilitate more precise delivery and minimise paravalvular regurgitation. The safety and efficacy of the Lotus valve are being studied systematically in the REPRISE clinical trial programme.

  13. Design and Experimental Performance of a Two Stage Partial Admission Turbine, Task B.1/B.4

    NASA Technical Reports Server (NTRS)

    Sutton, R. F.; Boynton, J. L.; Akian, R. A.; Shea, Dan; Roschak, Edmund; Rojas, Lou; Orr, Linsey; Davis, Linda; King, Brad; Bubel, Bill

    1992-01-01

    A three-inch mean diameter, two-stage turbine with partial admission in each stage was experimentally investigated over a range of admissions and angular orientations of admission arcs. Three configurations were tested in which first stage admission varied from 37.4 percent (10 of 29 passages open, 5 per side) to 6.9 percent (2 open, 1 per side). Corresponding second stage admissions were 45.2 percent (14 of 31 passages open, 7 per side) and 12.9 percent (4 open, 2 per side). Angular positions of the second stage admission arcs with respect to the first stage varied over a range of 70 degrees. Design and off-design efficiency and flow characteristics for the three configurations are presented. The results indicated that peak efficiency and the corresponding isentropic velocity ratio decreased as the arcs of admission were decreased. Both efficiency and flow characteristics were sensitive to the second stage nozzle orientation angles.

  14. Intermittent stuck valve after aortic valve replacement with a mechanical valve

    PubMed Central

    Luo, Wenzong; Wang, Xinxin; Li, Jing; Mu, Yun; Ni, Yiming

    2017-01-01

    Abstract Background: Intermittent stuck valve after mechanical valve replacement surgery is a very rare and severe complication. Case summary: We present 1 case of a 53-year-old woman after aortic valve replacement for severe aortic valve stenosis combined with hypertrophy septum. She was diagnosed with intermittent stuck valve only 1 day after surgery by clinical symptoms, intraoperative transoesophageal echocardiogram, and intraoperative findings. Conclusions: Although indications for concomitant myectomy during aortic valve replacement are not clear, we recommend myectomy to prevent stuck valve after St Jude Medical Regent prosthesis replacement for severe aortic valve stenosis combined with hypertrophy septum. PMID:28248877

  15. 22 CFR 229.300 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Admission. 229.300 Section 229.300 Foreign... and Recruitment Prohibited § 229.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission, or be subjected to discrimination in admission, by any recipient to which §§...

  16. 22 CFR 229.300 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Admission. 229.300 Section 229.300 Foreign... and Recruitment Prohibited § 229.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission, or be subjected to discrimination in admission, by any recipient to which §§...

  17. 22 CFR 146.300 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Admission. 146.300 Section 146.300 Foreign... Recruitment Prohibited § 146.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission, or be subjected to discrimination in admission, by any recipient to which §§ 146.300...

  18. 10 CFR 1042.300 - Admission.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Admission. 1042.300 Section 1042.300 Energy DEPARTMENT OF... Prohibited § 1042.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission, or be subjected to discrimination in admission, by any recipient to which §§ 1042.300 through...

  19. 44 CFR 68.9 - Admissible evidence.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Admissible evidence. 68.9 Section 68.9 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... admissible. (b) Documentary and oral evidence shall be admissible. (c) Admissibility of non-expert...

  20. College Admissions Policies for the 1970's.

    ERIC Educational Resources Information Center

    College Entrance Examination Board, New York, NY.

    The papers included in this collection are (1) "Problems and Issues Confronting the Admissions Community" by Clyde Vroman; (2) "Frozen Assumptions in Admissions" by B. Alden Thresher; (3) "The Effect of Federal Programs on Admissions Policies" by John F. Morse; (4) "State Plans for Higher Education and Their Influence on Admissions" by Charles W.…

  1. 45 CFR 618.300 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 618.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission, or be subjected to discrimination in admission, by...

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

    DOEpatents

    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.

  3. Recent improvements in check valve monitoring methods

    SciTech Connect

    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.

  4. Recent improvements in check valve monitoring methods

    SciTech Connect

    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.

  5. Ten-year experience with the porcine bioprosthetic valve: interrelationship of valve survival and patient survival in 1,050 valve replacements.

    PubMed

    Jones, E L; Weintraub, W S; Craver, J M; Guyton, R A; Cohen, C L; Corrigan, V E; Hatcher, C R

    1990-03-01

    The porcine bioprosthetic valve was used in 440 patients having isolated mitral valve replacement (MVR), 522 patients having isolated aortic valve replacement (AVR), and 88 patients having MVR + AVR between 1974 and 1981. Patients with associated surgical procedures were excluded. Mean follow-up was 8.3 years. At 10 years, there was no difference in patient survival between those having AVR and those having MVR. Reoperations were performed on 192 patients. Endocarditis was the reason for reoperation in 3.7% of patients who had MVR and 10.6% of those who had AVR. Structural valve degeneration was the reason for reoperation in 89.7% of MVR patients and 78.8% of AVR patients (p = 0.04). Hospital mortality among patients having valve reoperations was 4.7%. At 10 years, the freedom from valve reoperation for all causes and from structural valve degeneration was significantly better for the AVR group than the MVR group (74% +/- 3% versus 61% +/- 4%, p = 0.004; and 79% +/- 3% versus 63% +/- 4%, p = 0.0006, respectively). For patients in their 60s, the 10-year freedom from reoperation was 92% +/- 2% for AVR and 80% +/- 6% for MVR (p = not significant). At 10 years, freedom from cardiac-related death and valve reoperation was best for both MVR and AVR patients in their 60s. Patients 70 years old or older rarely had reoperation but died before valve failure occurred. The 10-year freedom from all major valve-related events (cardiac-related death, reoperation, thromboembolism, endocarditis, and anticoagulant-related bleeding) was practically the same for both MVR and AVR patients (48% +/- 3% versus 49% +/- 3%, respectively). The porcine bioprosthetic valve is the valve of choice only for patients 60 years old or older. Patients in their 70s have an extremely low rate of reoperation but a high rate of cardiac-related death and do not outlive the prostheses.

  6. 14 CFR 23.995 - Fuel valves and controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel valves and controls. 23.995 Section 23... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant Fuel System Components § 23.995 Fuel valves and controls. (a) There must be a means to allow appropriate flight...

  7. 14 CFR 23.995 - Fuel valves and controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel valves and controls. 23.995 Section 23... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant Fuel System Components § 23.995 Fuel valves and controls. (a) There must be a means to allow appropriate flight...

  8. Correlation of Exhaust-Valve Temperatures with Engine Operating Conditions and Valve Design in an Air-Cooled Cylinder

    NASA Technical Reports Server (NTRS)

    Zipkin, M A; Sanders, J C

    1945-01-01

    A semiempirical equation correlating exhaust-valve temperatures with engine operating conditions and exhaust-valve design has been developed. The correlation is based on the theory correlating engine and cooling variables developed in a previous NACA report. In addition to the parameters ordinarily used in the correlating equation, a term is included in the equation that is a measure of the resistance of the complex heat-flow paths between the crown of the exhaust valve and a point on the outside surface of the cylinder head. A means for comparing exhaust valves of different designs with respect to cooling is consequently provided. The necessary empirical constants included in the equation were determined from engine investigations of a large air-cooled cylinder. Tests of several valve designs showed that the calculated and experimentally determined exhaust-valve temperatures were in good agreement.

  9. Miniature electrically operated diaphragm valve

    DOEpatents

    Adkins, Douglas R.; Spletzer, Barry L.; Wong, Chungnin C.; Frye-Mason, Gregory C.; Fischer, Gary J.; Hesketh, Peter J.

    2001-01-01

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

  10. Subsea production test valve assembly

    SciTech Connect

    Yates, P.D.

    1988-03-22

    In the subsea test assembly securable within a blowout preventer stack above a subterranean well and positionable between upper and lower portions of a tubular conduit in fluid communication with a production zone within the well, the test assembly is described including an upper subassembly carriable with the upper conduit portion, a lower subassembly carriable with the lower conduit portion, and valve means in the lower subassembly manipulatable between opened and closed positions to control fluid flow within the conduit. The improvement comprises: the upper subassembly including an upper housing and first rigid dog means fixedly secured to the upper housing; the lower subassembly including a lower housing and second rigid dog means fixedly secured to the lower housing; the first rigid dog means positionable between a latch position for latching the upper and lower subassemblies and an unlatch position for unlatching the upper and lower subassemblies upon rotational movement of the first dog means with respect to the second dog means; and lock means axially movable relative to the first and second dog means from a lock position for limiting rotational movement of the first dog means with respect to the second dog means to an unlock position for allowing the first dog means to rotate relative to the second dog means and unlatch the upper subassembly from the lower subassembly.

  11. Face-Sealing Butterfly Valve

    NASA Technical Reports Server (NTRS)

    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.

  12. Long life valve design concepts

    NASA Technical Reports Server (NTRS)

    Jones, J. R.; Hall, A. H., Jr.

    1975-01-01

    Valve concept evaluation, final candidate selection, design, manufacture, and demonstration testing of a pneumatically actuated 10-inch hybrid poppet butterfly shutoff valve are presented. Conclusions and recommendations regarding those valve characteristics and features which would serve to guide in the formulation of future valve procurements are discussed. The pertinent design goals were temperature range of plus 200 to minus 423 F, valve inlet pressure 35 psia, actuation pressure 750 psia, main seal leakage 3 x 0.00001 sccs at 35 psia valve inlet pressure, and a storage and operating life of 10 years. The valve was designed to be compatible with RP-1, propane, LH2, LO2, He, and N2.

  13. Quartz ball valve

    NASA Technical Reports Server (NTRS)

    Goetz, C.; Ingle, W. M. (Inventor)

    1980-01-01

    A ball valve particularly suited for use in the handling of highly corrosive fluids is described. It is characterized by a valve housing formed of communicating segments of quartz tubing, a pair of communicating sockets disposed in coaxial alignment with selected segments of tubing for establishing a pair of inlet ports communicating with a common outlet port, a ball formed of quartz material supported for displacement between the sockets and configured to be received alternately thereby, and a valve actuator including a rod attached to the ball for selectively displacing the ball relative to each of the sockets for controlling fluid flow through the inlet ports.

  14. Mesofluidic two stage digital valve

    DOEpatents

    Jansen, John F; Love, Lonnie J; Lind, Randall F; Richardson, Bradley S

    2013-12-31

    A mesofluidic scale digital valve system includes a first mesofluidic scale valve having a valve body including a bore, wherein the valve body is configured to cooperate with a solenoid disposed substantially adjacent to the valve body to translate a poppet carried within the bore. The mesofluidic scale digital valve system also includes a second mesofluidic scale valve disposed substantially perpendicular to the first mesofluidic scale valve. The mesofluidic scale digital valve system further includes a control element in communication with the solenoid, wherein the control element is configured to maintain the solenoid in an energized state for a fixed period of time to provide a desired flow rate through an orifice of the second mesofluidic valve.

  15. Engine valve train with inner and outer cam followers

    SciTech Connect

    Patterson, C.E.

    1988-05-03

    This patent describes a valve train for an internal combustion engine of the type having an engine block means including a cylinder and with a cylinder head defining two inlet ports and two exhaust ports for the cylinder, a valve reciprocably located in each of the inlet ports and the exhaust ports with the two valves associated with the inlet ports alternating with the two valves associated with the exhaust ports, with all the valves being arranged in a splayed configuration. The engine block means further include an upper support member fixed to the cylinder head, an engine driven camshaft operatively mounted in the engine block means and having a pair of axially spaced apart exhaust cams thereof and an inlet cam thereon located between the exhaust cams, rocker arms each operatively associated at one end thereof with an associate one of the valves, a stepped bore in the cylinder head and upper support means formed at right angles to the cams on the camshaft and above the cams, plural means each defining a rocking support intermediate the ends of an associate one of the valves, and a tubular inner inlet lifter and a tubular outer lifter reciprocably journaled in the stepped bore with the inner lifter engaging the inlet cam and being operative to engage the opposite end of each one of the rocker arm associated with the inlet valves. The outer lifter engages the exhaust cams and is operative to engage the opposite end of each one of the rocker arms associated with the exhaust valves, the axis of reciprocation of the inner and outer lifters being located on the intersection of two imaginary planes extending through the axis of reciprocation of opposed sets of the valves.

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

    PubMed

    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.

  17. Redo aortic valve surgery versus transcatheter valve-in-valve implantation for failing surgical bioprosthetic valves: consecutive patients in a single-center setting

    PubMed Central

    Wottke, Michael; Deutsch, Marcus-André; Krane, Markus; Piazza, Nicolo; Lange, Ruediger; Bleiziffer, Sabine

    2015-01-01

    Background Due to a considerable rise in bioprosthetic as opposed to mechanical valve implantations, an increase of patients presenting with failing bioprosthetic surgical valves in need of a reoperation is to be expected. Redo surgery may pose a high-risk procedure. Transcatheter aortic valve-in-valve implantation is an innovative, less-invasive treatment alternative for these patients. However, a comprehensive evaluation of the outcome of consecutive patients after a valve-in-valve TAVI [transcatheter aortic valve-in-surgical aortic valve (TAV-in-SAV)] as compared to a standard reoperation [surgical aortic valve redo-operation (SAV-in-SAV)] has not yet been performed. The goal of this study was to compare postoperative outcomes after TAV-in-SAV and SAV-in-SAV in a single center setting. Methods All SAV-in-SAV and TAV-in-SAV patients from January 2001 to October 2014 were retrospectively reviewed. Patients with previous mechanical or transcatheter valves, active endocarditis and concomitant cardiac procedures were excluded. Patient characteristics, preoperative data, post-procedural complications, and 30-day mortality were collected from a designated database. Mean values ± SD were calculated for all continuous variables. Counts and percentages were calculated for categorical variables. The Chi-square and Fisher exact tests were used to compare categorical variables. Continuous variables were compared using the t-test for independent samples. A 2-sided P value <0.05 was considered statistically significant. Results A total of 102 patients fulfilled the inclusion criteria, 50 patients (49%) underwent a transcatheter valve-in-valve procedure, while 52 patients (51%) underwent redo-surgery. Patients in the TAV-in-SAV group were significantly older, had a higher mean logistic EuroSCORE and exhibited a lower mean left ventricular ejection fraction than patients in the SAV-in-SAV group (78.1±6.7 vs. 66.2±13.1, P<0.001; 27.4±18.7 vs. 14.4±10, P<0.001; and 49.8±13

  18. [A case of infective Aerococcus urinae endocarditis successfully treated by aortic valve replacement].

    PubMed

    Miyazato, Akiko; Ohkusu, Kiyohumi; Ishii, Shunsuke; Sasaoka, Taishi; Ikeda, Masahiro; Niinami, Hiroshi; Ezaki, Takayuki; Mitsutake, Kotaro

    2011-11-01

    Aerococcus urinae is a endocarditis rare causative organism with low virulene. We report an A. urinae endocarditis case treated by aortic valve replacement. An 80-year-old woman hospitalized for urinary tract infection and hydronephrosis due to three-week renal calculi. Blood culture on admission isolated Streptococcus acidominimus. During the course, she was transferred to our care for surgical intervention after developing congestive heart failure due to severe aortic regurgitation. Echocardiographic findings indicated infective endocarditis. She underwent aortic valve replacement, and gram staining of the resected valve tissue showed gram-positive cocci, although valve culture was negative. PCR amplification and DNA sequencing using the valve material matched an A. urinae sequence. The woman recovered and was discharged six weeks after antibiotic treatment.

  19. Transapical aortic valve and mitral valve in ring prosthesis implantation - a new advance in transcatheter procedures.

    PubMed

    Neves, Paulo C; Paulo, Nelson Santos; Gama, Vasco; Vouga, Luís

    2014-08-01

    Transcatheter valve implantation offers a new treatment modality to those patients whose general condition makes conventional surgery very risky. However, the transcatheter option has only been available for the aortic valve. We describe a case of a successful implantation of two Edwards SAPIEN(®) 26 and 29 mm transapical valves, respectively, in aortic and mitral positions, on a 74-year-old patient with severe aortic and mitral stenosis. The procedure progressed uneventfully. Predischarge echocardiogram showed a peak aortic gradient of 20 mmHg, mild periprosthetic regurgitation, peak and mean mitral gradients of 12 and 4, respectively, and moderate (II/IV) periprosthetic regurgitation. Indications for transapical valve implantation will rapidly increase in the near future. It is essential to individualize the treatment be applied for each patient, in order to optimize the success of the procedure.

  20. Mitral Valve Prolapse

    MedlinePlus

    ... Kawasaki Disease Long Q-T Syndrome Marfan Syndrome Metabolic Syndrome Mitral Valve Prolapse Myocardial Bridge Myocarditis Obstructive Sleep Apnea Pericarditis Peripheral Vascular Disease Rheumatic Fever Sick Sinus Syndrome Silent Ischemia Stroke Sudden ...

  1. Pulmonary valve stenosis

    MedlinePlus

    ... valvuloplasty - pulmonary 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 ...

  2. Valve Repair or Replacement

    MedlinePlus

    ... invasive valve surgery can be done using a robot. Robotic surgery does not require a large incision ... the procedure. The Texas Heart Institute has a robot. With robotic surgery, the surgeon has a control ...

  3. Mitral Valve Prolapse.

    ERIC Educational Resources Information Center

    Bergy, Gordon G.

    1980-01-01

    Mitral valve prolapse is the most common heart disease seen in college and university health services. It underlies most arrhythmia and many chest complaints. Activity and exercise restrictions are usually unnecessary. (Author/CJ)

  4. Pulmonary Valve Stenosis

    MedlinePlus

    ... as mild, moderate or severe, depending on a measurement of the blood pressure difference between the right ... balloon, widening the narrowed valve to increase blood flow, and then removes the balloon. The most common ...

  5. Bicuspid aortic valve

    MedlinePlus

    ... stiff and not open up. This is called aortic stenosis , which causes the heart to pump harder than usual to get blood through the valve. The aorta may become enlarged with this condition. BAV is ...

  6. Electromechanically Actuated Valve for Controlling Flow Rate

    NASA Technical Reports Server (NTRS)

    Patterson, Paul

    2007-01-01

    A proposed valve for controlling the rate of flow of a fluid would include an electric-motor-driven ball-screw mechanism for adjusting the seating element of the valve to any position between fully closed and fully open. The motor would be of a type that can be electronically controlled to rotate to a specified angular position and to rotate at a specified rate, and the ball screw would enable accurate linear positioning of the seating element as a function of angular position of the motor. Hence, the proposed valve would enable fine electronic control of the rate of flow and the rate of change of flow. The uniqueness of this valve lies in a high degree of integration of the actuation mechanism with the flow-control components into a single, relatively compact unit. A notable feature of this integration is that in addition to being a major part of the actuation mechanism, the ball screw would also be a flow-control component: the ball screw would be hollow so as to contain part of the main flow passage, and one end of the ball screw would be the main seating valve element. The relationships among the components of the valve are best understood by reference to the figure, which presents meridional cross sections of the valve in the fully closed and fully open positions. The motor would be supported by a bracket bolted to the valve body. By means of gears or pulleys and a timing belt, motor drive would be transmitted to a sleeve that would rotate on bearings in the valve body. A ball nut inside the sleeve would be made to rotate with the sleeve by use of a key. The ball screw would pass through and engage the ball nut. A key would prevent rotation of the ball screw in the valve body while allowing the ball screw to translate axially when driven by the ball nut. The outer surface of the ball screw would be threaded only in a mid-length region: the end regions of the outer surface of the ball screw would be polished so that they could act as dynamic sealing surfaces

  7. Liquid blocking check valve

    DOEpatents

    Merrill, John T.

    1984-01-01

    A liquid blocking check valve useful particularly in a pneumatic system utilizing a pressurized liquid fill chamber. The valve includes a floatable ball disposed within a housing defining a chamber. The housing is provided with an inlet aperture disposed in the top of said chamber, and an outlet aperture disposed in the bottom of said chamber in an offset relation to said inlet aperture and in communication with a cutaway side wall section of said housing.

  8. Valve for gas centrifuges

    DOEpatents

    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.

  9. Bicuspid Aortic Valve

    DTIC Science & Technology

    2006-08-01

    severe aortic stenosis . Figure 1F. Oblique axial cine bright blood imaging through the valve plane of the aorta, demonstrates the aortic valve to...the ascending aorta. This moderate to large jet is consistent with moderate to severe aortic stenosis . No diastolic jet to suggest aortic ...conditions. Functional impairment of the aortic valve—namely aortic stenosis and aortic regurgitation—is the most common complication (in up to 68-85% of

  10. Posterior Urethral Valves in Children: Pattern of Presentation and Outcome of Initial Treatment in Ile-Ife, Nigeria

    PubMed Central

    Talabi, Ademola Olusegun; Sowande, Oludayo Adedapo; Etonyeaku, Amarachukwu Chiduziem; Salako, Abdulkadir A; Adejuyigbe, Olusanya

    2015-01-01

    Background: The management of posterior urethral valves (PUV) and its sequelae is still a challenge to most pediatric surgeons in our environment due to late presentation and inadequate facilities for long-term evaluation and treatment. Despite initial successful treatment about 40% would develop chronic renal failure. The aim is to describe the presentation, management and outcome of the initial treatment in boys with PUV. Materials and Methods: It is a retrospective analysis of PUV in boys 8 years and below over a 17 years period. Demographic characteristics, clinical features, investigations, and treatment outcome were reviewed. Results: Thirty-seven cases were analyzed. The median age was 5 months (range from birth to 8 years). Three (8.1%) patients had prenatal ultrasound diagnosis. The most common presentation was voiding dysfunction 37 (100%). Part of the preoperative investigation included micturating cystourethrogram (n = 31: 83.8%) and abdomino-pelvic ultrasonography (n = 37:(100%). The mean serum creatinine value of those who presented within the first 30 days of life and those who presented afterwards were 325 (±251) µmol/L and 141 (±100) µmol/L respectively, P = 0.003. Surgical interventions included trans-vesical excision of valves (n = 9: 28.1%), valvotomy (n = 10: 31.3%), balloon avulsion (n = 8: 25.0%), vesicostomy (n = 4: 12.5%) and endoscopic valve avulsion (n = 1: 3.1%). Seventeen (56.7%) patients had serum creatinine >70.4 µmol/L after 1-month of valve excision. Five (13.5%) patients had postrelief complications and 5 (13.5%) died on admission. Ninety percentage (27/30) of patients had poor prognostic indices. Conclusions: The initial treatment outcome was good but most had poor prognostic factors. PMID:26425072

  11. Valve operating device for internal combustion engine

    SciTech Connect

    Konno, T.; Sugai, T.

    1989-07-04

    This patent describes a valve operating device for an internal combustion engine. It has a pair of rocker arms pivotally mounted on a rocker shaft and separately operable by different cams on a camshaft for different modes of operation of an intake or exhaust valve operatively connected to one of the rocker arms, comprising each rocker arm having a portion with a surface substantially parallel to and confronting the surface of the other rocker arm, coupling means in the portions for selectively coupling the rocker arms including a coupling pin movable in a direction substantially perpendicular to the axis of the rocker arm shaft.

  12. 32 CFR 242.5 - Admission procedures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... HEALTH SCIENCES § 242.5 Admission procedures. (a) Application—(1) Civilians. Civilians seeking admission... conditionally select candidates to fill available class spaces. Those conditionally selected shall be the...

  13. Is Contextualised Admission the Answer to the Access Challenge?

    ERIC Educational Resources Information Center

    Mountford-Zimdars, Anna; Moore, Joanne; Graham, Janet

    2016-01-01

    This article reviews the idea of contextualising applicants to higher education in order to widen access. First, the meaning of contextualised admissions (CAs) is discussed before laying out the rationale for contextualising applicants and the beneficiaries of the policy. The final sections discuss key critiques of CA and conclude by arguing that…

  14. Mitral disc-valve variance

    PubMed Central

    Berroya, Renato B.; Escano, Fernando B.

    1972-01-01

    This report deals with a rare complication of disc-valve prosthesis in the mitral area. A significant disc poppet and struts destruction of mitral Beall valve prostheses occurred 20 and 17 months after implantation. The resulting valve incompetence in the first case contributed to the death of the patient. The durability of Teflon prosthetic valves appears to be in question and this type of valve probably will be unacceptable if there is an increasing number of disc-valve variance in the future. Images PMID:5017573

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

    PubMed Central

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

    2016-01-01

    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. PMID:27973449

  16. Admission Requirements for Education Doctoral Programs at Top 20 American Universities

    ERIC Educational Resources Information Center

    Walker, Gabriela

    2008-01-01

    A quantitative analysis of the admissions requirements guidelines of the education doctoral programs at the top 20 American universities was conducted. An Internet search was used to obtain information on top-ranked world and U.S. universities. Admission requirements typically include, at minimum, an application fee (mean 55.5 USD), previous…

  17. 9. BUTTERFLY VALVE CONTROL DIABLO POWERHOUSE. BUTTERFLY VALVES WERE MANUFACTURED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. BUTTERFLY VALVE CONTROL DIABLO POWERHOUSE. BUTTERFLY VALVES WERE MANUFACTURED BY THE PELTON WATER WHEEL COMPANY IN 1931, 1989. - Skagit Power Development, Diablo Powerhouse, On Skagit River, 6.1 miles upstream from Newhalem, Newhalem, Whatcom County, WA

  18. Implantation of the CoreValve percutaneous aortic valve.

    PubMed

    Lamarche, Yoan; Cartier, Raymond; Denault, André Y; Basmadjian, Arsène; Berry, Colin; Laborde, Jean-Claude; Bonan, Raoul

    2007-01-01

    Surgical aortic valve replacement is the only recommended treatment for significant aortic valve stenosis. Percutaneous aortic valve replacement appears to be a novel option for high-risk patients. We report the implantation of the ReValving system (CoreValve, Paris, France) in a 64-year-old woman who was refused aortic valve replacement surgery for critical aortic stenosis and left ventricular dysfunction because of severe pulmonary fibrosis. After anesthesia, the patient was put on femorofemoral cardiopulmonary bypass, and underwent a balloon valvuloplasty with subsequent retrograde aortic valve replacement by the ReValving system. Transesophageal echocardiographic monitoring of the patient's hemodynamics showed immediate improvements of the valvular area and left ventricular ejection fraction and only traces of paravalvular leaks. The patient was easily weaned from ventilation and resumed activity soon after the surgery. A multidisciplinary approach is presently necessary to offer a reliable and safe procedure.

  19. Perceval Sutureless Valve – are Sutureless Valves Here?

    PubMed Central

    Chandola, Rahul; Teoh, Kevin; Elhenawy, Abdelsalam; Christakis, George

    2015-01-01

    With the advent of transcatheter aortic valve implantation (TAVI) techniques, a renewed interest has developed in sutureless aortic valve concepts in the last decade. The main feature of sutureless aortic valve implantation is the speed of insertion, thus making implantation easier for the surgeon. As a result, cross clamp times and myocardial ischemia may be reduced. The combined procedures (CABG with AVR in particular) can be done with a short cross clamp time. Perceval valve also provides an increased effective orifice area as compared with a stented bioprosthesis. Sutureless implantation of the Perceval valve is not only associated with shorter cross-clamp and cardiopulmonary bypass times but improved clinical outcomes too. This review covers the sutureless aortic valves and their evolution, with elaborate details on Perceval S valve in particular (which is the most widely used sutureless valve around the globe). PMID:25394851

  20. 18 CFR 1317.300 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Admission. 1317.300 Section 1317.300 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY NONDISCRIMINATION ON... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1317.300 Admission. (a) General....

  1. 18 CFR 1317.300 - Admission.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Admission. 1317.300 Section 1317.300 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY NONDISCRIMINATION ON... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1317.300 Admission. (a) General....

  2. 38 CFR 23.300 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Admission. 23.300 Section 23.300 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS (CONTINUED... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 23.300 Admission. (a) General....

  3. 18 CFR 1317.300 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Admission. 1317.300 Section 1317.300 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY NONDISCRIMINATION ON... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1317.300 Admission. (a) General....

  4. 36 CFR 1211.300 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Admission. 1211.300 Section 1211.300 Parks, Forests, and Public Property NATIONAL ARCHIVES AND RECORDS ADMINISTRATION GENERAL RULES... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1211.300 Admission. (a) General....

  5. An Economic Model for Selective Admissions

    ERIC Educational Resources Information Center

    Haglund, Alma

    1978-01-01

    The author presents an economic model for selective admissions to postsecondary nursing programs. Primary determinants of the admissions model are employment needs, availability of educational resources, and personal resources (ability and learning potential). As there are more applicants than resources, selective admission practices are…

  6. 17 CFR 12.33 - Admissions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... REPARATIONS Discovery § 12.33 Admissions. (a) Request for admissions. Any party may, within the time permitted... truth of any matters set forth in the request that relate to statements or opinions of fact or of the...) Reply. Each matter of which an admission is requested shall be separately set forth. The matter...

  7. Admission to Medical Education in Ten Countries.

    ERIC Educational Resources Information Center

    Burn, Barbara B., Ed.

    As part of a study of access and admission to higher education in Germany and the United States, a group of papers on medical admissions in various countries was commissioned. The papers presented in this book reveal wide differences in admissions policies and procedures. Barbara Burn examines some of the major issues in a foreword: representation…

  8. The Journal of College Admission Ethics Series.

    ERIC Educational Resources Information Center

    Loveland, Elaina C., Ed.; Raynor, Joyce, Ed.

    This book is the first significant body of literature on ethics in college admission published by the National Association for College Admission Counseling. The series is a select compilation of articles on ethics published in the Journal of College Admission in 1998 and 1999. The book is a source of information for the beginning and experienced…

  9. Reducing admissions for people with diabetes.

    PubMed

    Allan, Belinda

    Reversing the rise in emergency hospital admissions is an NHS priority. These admissions impact on elective capacity and waiting times and are unsustainable. The risk of hospitalisation for people with diabetes is almost twice that for others. Commissioners need to address admissions associated with diabetes and new guidance offers best-practice solutions.

  10. The Role of Noncognitive Assessment in Admissions

    ERIC Educational Resources Information Center

    Hoerle, Heather

    2014-01-01

    Confident that understanding and employing new approaches to assessment is a top priority for admissions professionals, the Secondary School Admission Test Board (SSATB) recently launched a Think Tank on the Future of Admission Assessment, with a two-year timeline and a charge to educate its membership and inspire greater innovation in admissions…

  11. Merit and Competition in Selective College Admissions

    ERIC Educational Resources Information Center

    Killgore, Leslie

    2009-01-01

    Using interview data from 34 admissions officers at 17 elite colleges, this paper compares two perspectives shaping admissions policy. Admissions officers apply a "merit" perspective that relies on indicators of student academic and nonacademic achievement. They also employ a "competition" perspective that evaluates student characteristics…

  12. Toward a Sociology of Law School Admissions.

    ERIC Educational Resources Information Center

    Erlanger, Howard S.

    1984-01-01

    The law school admission process plays a major role in determining the social class origins and ethnic composition of the bar, and perhaps also the nonlegal skills lawyers will have. Research is incomplete; consideration of admission criteria, the composition and processes of admissions committees, and applicant self-selection is advisable. (MSE)

  13. 29 CFR 36.300 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Secretary of Labor NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 36.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission, or...

  14. 10 CFR 1042.300 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... ENERGY (GENERAL PROVISIONS) NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1042.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission,...

  15. 10 CFR 1042.300 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... ENERGY (GENERAL PROVISIONS) NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1042.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission,...

  16. 29 CFR 36.300 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Secretary of Labor NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 36.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission, or...

  17. 29 CFR 36.300 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Secretary of Labor NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 36.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission, or...

  18. 7 CFR 501.2 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 6 2011-01-01 2011-01-01 false Admission. 501.2 Section 501.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON U.S. MEAT ANIMAL RESEARCH CENTER, CLAY CENTER, NEBRASKA § 501.2 Admission. Admission to...

  19. 7 CFR 501.2 - Admission.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 6 2013-01-01 2013-01-01 false Admission. 501.2 Section 501.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON U.S. MEAT ANIMAL RESEARCH CENTER, CLAY CENTER, NEBRASKA § 501.2 Admission. Admission to...

  20. 7 CFR 501.2 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 6 2014-01-01 2014-01-01 false Admission. 501.2 Section 501.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON U.S. MEAT ANIMAL RESEARCH CENTER, CLAY CENTER, NEBRASKA § 501.2 Admission. Admission to...

  1. 7 CFR 501.2 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 6 2012-01-01 2012-01-01 false Admission. 501.2 Section 501.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON U.S. MEAT ANIMAL RESEARCH CENTER, CLAY CENTER, NEBRASKA § 501.2 Admission. Admission to...

  2. 7 CFR 501.2 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Admission. 501.2 Section 501.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON U.S. MEAT ANIMAL RESEARCH CENTER, CLAY CENTER, NEBRASKA § 501.2 Admission. Admission to...

  3. The Evolution of College Admission Requirements

    ERIC Educational Resources Information Center

    Beale, Andrew V.

    2012-01-01

    The development of college admissions requirements during the seventeenth and eighteenth centuries was basically the story of the admission policies and practices at Harvard College. Candidates for admission were examined on their ability to read and translate Latin and Greek, and a careful check was made of their character and background. With…

  4. Fast closing valve

    SciTech Connect

    Hanson, C.L.

    1984-01-10

    A valve is provided for protecting the high vacuum of a particle accelerator in the event of air leakage, wherein the valve provides an axially symmetrical passage to avoid disturbance of the partical beam during normal operation, and yet enables very rapid and tight closure of the beam-carrying pipe in the event of air leakage. The valve includes a ball member which can rotate between a first position wherein a bore in the member is aligned with the beam pipe, and a second position out of line with the pipe. A seal member is flexibly sealed to the pipe, and has a seal end which can move tightly against the ball member after the bore has rotated out of line with the pipe, to thereby assure that the seal member does not retard rapid rotation of the ball valve member. The ball valve member can be rapidly rotated by a conductive arm fixed to it and which is rotated by the discharge of a capacitor bank through coils located adjacent to the arm.

  5. Fast closing valve

    DOEpatents

    Hanson, Clark L.

    1984-01-10

    A valve is provided for protecting the high vacuum of a particle accelera in the event of air leakage, wherein the valve provides an axially symmetrical passage to avoid disturbance of the partical beam during normal operation, and yet enables very rapid and tight closure of the beam-carrying pipe in the event of air leakage. The valve includes a ball member (30) which can rotate between a first position wherein a bore (32) in the member is aligned with the beam pipe, and a second position out of line with the pipe. A seal member (38) is flexibly sealed to the pipe, and has a seal end which can move tightly against the ball member after the bore has rotated out of line with the pipe, to thereby assure that the seal member does not retard rapid rotation of the ball valve member. The ball valve member can be rapidly rotated by a conductive arm (40) fixed to it and which is rotated by the discharge of a capacitor bank through coils (44, 45) located adjacent to the arm.

  6. Sutureless aortic valve replacement

    PubMed Central

    Phan, Kevin

    2015-01-01

    The increasing incidence of aortic stenosis and greater co-morbidities and risk profiles of the contemporary patient population has driven the development of minimally invasive aortic valve surgery and percutaneous transcatheter aortic valve implantation (TAVI) techniques to reduce surgical trauma. Recent technological developments have led to an alternative minimally invasive option which avoids the placement and tying of sutures, known as “sutureless” or rapid deployment aortic valves. Potential advantages for sutureless aortic prostheses include reducing cross-clamp and cardiopulmonary bypass (CPB) duration, facilitating minimally invasive surgery and complex cardiac interventions, whilst maintaining satisfactory hemodynamic outcomes and low paravalvular leak rates. However, given its recent developments, the majority of evidence regarding sutureless aortic valve replacement (SU-AVR) is limited to observational studies and there is a paucity of adequately-powered randomized studies. Recently, the International Valvular Surgery Study Group (IVSSG) has formulated to conduct the Sutureless Projects, set to be the largest international collaborative group to investigate this technology. This keynote lecture will overview the use, the potential advantages, the caveats, and current evidence of sutureless and rapid deployment aortic valve replacement (AVR). PMID:25870807

  7. Reduction of calcification by various treatments in cardiac valves.

    PubMed

    Rao, K P; Shanthi, C

    1999-01-01

    The importance of glutaraldehyde pretreated bioprosthetic heart valves fabricated from bovine pericardium or porcine aortic valves is well realized in the management of valvular heart diseases. But, calcification limits the durability and is the most frequent cause of failure of these bioprosthetic heart valves. Various research groups in the world are actively involved in describing, understanding, and preventing calcification of bioprosthetic heart valves. Since there is no satisfactory clinical means for preventing or treating this disorder, attempts are made to improve the anticalcification properties of the replacement valves in the preparation stage itself. Research in this area is very active, and many newer approaches are made to mitigate the problem. An attempt has been made in the present article to review various theories put forward to explain the causative factors involved and mechanistic aspects of biocalcification and to present various strategies attempted for the prevention of calcification with the special feature on the work done in the area in our laboratory.

  8. Computerized intraoperative calculation of instantaneous prosthetic aortic valve area.

    PubMed

    DiSesa, V J; Lachman, P; Collins, J J; Cohn, L H

    1988-01-01

    Improved assessment of valve area is essential to understanding the performance of prosthetic valves. The authors studied six patients undergoing aortic valve replacement using mechanical (ME) or porcine (PO) prostheses. Instantaneous cardiac output (CO) (L/min) was measured in the aorta using an ultrasonic flow probe. Left ventricular and aortic pressures (mmHg) were measured using Millar catheters. Data were analyzed using an IBM PC-AT. Valve area (cm2) was determined using Gorlin's formula (AG) and a new formula for instantaneous area derived mathematically and using a theoretic constant. AG, mean (AI) and peak (Apk) instantaneous areas were compared to geometric measures of area (Aactual) in vitro. Peak instantaneous area correlates best with measured area. Intraoperative assessment using the ultrasonic flow probe and computer analysis is helpful in understanding the dynamic properties of prosthetic valves in vivo.

  9. Aortic valve replacement with the De Bakey valve.

    PubMed

    Paton, B C; Pine, M B

    1976-10-01

    De Bakey prostheses were inserted in 29 patients with aortic valve disease between October, 1970, and May, 1972. Ten patients have died, but all but one of the remaining 19 have beel followed for a minimum of 19 months. Evaluation of the results in these subjects indicates that the function of the De Bakey valve compares favorably with that of other aortic valve prostheses.

  10. 81. View of 41 valve house (right) and 42 valve ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    81. View of 4-1 valve house (right) and 4-2 valve house (left); in the foreground is penstock which extends from Penstock No. 1 to the 4-1 valve house; looking south. Photo by Jet Lowe, HAER, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  11. 83. Interior of 42 valve house; the motor and valve ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    83. Interior of 4-2 valve house; the motor and valve mechanism is identical to that in the 4-1 valve house. Photo by Jet Lowe, HAER, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  12. What Is Mitral Valve Prolapse?

    MedlinePlus

    ... may not close tightly. These flaps normally help seal or open the valve. Much of the time, ... and tricuspid valves close. They form a tight seal that prevents blood from flowing back into the ...

  13. Medications for Heart Valve Symptoms

    MedlinePlus

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Medications for Heart Valve Symptoms Updated:Sep 21,2016 How do medications help people with valve problems? People who are ...

  14. Locking apparatus for gate valves

    DOEpatents

    Fabyan, Joseph; Williams, Carl W.

    1988-01-01

    A locking apparatus for fluid operated valves having a piston connected to the valve actuator which moves in response to applied pressure within a cylinder housing having a cylinder head, a catch block is secured to the piston, and the cylinder head incorporates a catch pin. Pressure applied to the cylinder to open the valve moves the piston adjacent to the cylinder head where the catch pin automatically engages the catch block preventing futher movement of the piston or premature closure of the valve. Application of pressure to the cylinder to close the valve, retracts the catch pin, allowing the valve to close. Included are one or more selector valves, for selecting pressure application to other apparatus depending on the gate valve position, open or closed, protecting such apparatus from damage due to premature closing caused by pressure loss or operational error.

  15. Locking apparatus for gate valves

    DOEpatents

    Fabyan, J.; Williams, C.W.

    A locking apparatus for fluid operated valves having a piston connected to the valve actuator which moves in response to applied pressure within a cylinder housing having a cylinder head, a catch block is secured to the piston, and the cylinder head incorporates a catch pin. Pressure applied to the cylinder to open the valve moves the piston adjacent to the cylinder head where the catch pin automatically engages the catch block preventing further movement of the piston or premature closure of the valve. Application of pressure to the cylinder to close the valve, retracts the catch pin, allowing the valve to close. Included are one or more selector valves, for selecting pressure application to other apparatus depending on the gate valve position, open or closed, protecting such apparatus from damage due to premature closing caused by pressure loss or operational error.

  16. Aortic valve surgery - minimally invasive

    MedlinePlus

    ... of the heart is reduced. This is called aortic stenosis. The aortic valve can be replaced using: Minimally ... RN, Wang A. Percutaneous heart valve replacement for aortic stenosis: state of the evidence. Ann Intern Med . 2010; ...

  17. Valve-spring Surge

    NASA Technical Reports Server (NTRS)

    Marti, Willy

    1937-01-01

    Test equipment is described that includes a system of three quartz indicators whereby three different pressures could be synchronized and simultaneously recorded on a single oscillogram. This equipment was used to test the reliction of waves at ends of valve spring, the dynamical stress of the valve spring for a single lift of the valve, and measurement of the curve of the cam tested. Other tests included simultaneous recording of the stress at both ends of the spring, spring oscillation during a single lift as a function of speed, computation of amplitude of oscillation for a single lift by harmonic analysis, effect of cam profile, the setting up of resonance, and forced spring oscillation with damping.

  18. Sliding valve pump

    SciTech Connect

    Rupert, C.L.

    1980-09-09

    A sliding valve pump for oil wells which includes a working barrel having a plurality of apertures located in spaced relationship in the wall thereof and a pair of travelling valves fitted within the working barrel and carried by a plunger rod, the valves also having a plurality of apertures or ports for periodic registration with the ports in the working barrel wall to facilitate pumping of fluid from an oil reservoir or pool to the surface. The pump is designed to pull the oil-gas mixture from the reservoir pool into the lower section of the working barrel on the downward stroke, and to subsequently pump the collected oil through the barrel and tubing upwardly toward the surface on the upward stroke.

  19. Variable Valve Actuation

    SciTech Connect

    Jeffrey Gutterman; A. J. Lasley

    2008-08-31

    Many approaches exist to enable advanced mode, low temperature combustion systems for diesel engines - such as premixed charge compression ignition (PCCI), Homogeneous Charge Compression Ignition (HCCI) or other HCCI-like combustion modes. The fuel properties and the quantity, distribution and temperature profile of air, fuel and residual fraction in the cylinder can have a marked effect on the heat release rate and combustion phasing. Figure 1 shows that a systems approach is required for HCCI-like combustion. While the exact requirements remain unclear (and will vary depending on fuel, engine size and application), some form of substantially variable valve actuation is a likely element in such a system. Variable valve actuation, for both intake and exhaust valve events, is a potent tool for controlling the parameters that are critical to HCCI-like combustion and expanding its operational range. Additionally, VVA can be used to optimize the combustion process as well as exhaust temperatures and impact the after treatment system requirements and its associated cost. Delphi Corporation has major manufacturing and product development and applied R&D expertise in the valve train area. Historical R&D experience includes the development of fully variable electro-hydraulic valve train on research engines as well as several generations of mechanical VVA for gasoline systems. This experience has enabled us to evaluate various implementations and determine the strengths and weaknesses of each. While a fully variable electro-hydraulic valve train system might be the 'ideal' solution technically for maximum flexibility in the timing and control of the valve events, its complexity, associated costs, and high power consumption make its implementation on low cost high volume applications unlikely. Conversely, a simple mechanical system might be a low cost solution but not deliver the flexibility required for HCCI operation. After modeling more than 200 variations of the

  20. Magnetostrictive valve assembly

    NASA Technical Reports Server (NTRS)

    Richard, James A. (Inventor)

    2008-01-01

    A magnetostrictive valve assembly includes a housing that defines a passage with a seat being formed therein. A magnetically-biased and axially-compressed magnetostrictive assembly slidingly fitted in the passage is configured as a hollow and open-ended conduit adapted to support a flow of a fluid therethrough. Current-carrying coil(s) disposed about the passage in the region of the magnetostrictive assembly generate a magnetic field in the passage when current flows through the coil(s). A hollow valve body with side ports is coupled on one end thereof to an axial end of the magnetostrictive assembly. The other end of the valve body is designed to seal with the seat formed in the housing's passage when brought into contact therewith.

  1. Management of moderate functional tricuspid valve regurgitation at the time of pulmonary valve replacement: is concomitant tricuspid valve repair necessary?

    PubMed

    Kogon, Brian; Patel, Manisha; Leong, Traci; McConnell, Michael; Book, Wendy

    2010-08-01

    Congenital heart defects with a component of pulmonary stenosis are often palliated in childhood by disrupting the pulmonary valve. Patients often undergo subsequent pulmonary valve replacement (PVR) to protect the heart from the consequences of pulmonary regurgitation. In the presence of associated moderate functional tricuspid valve (TV) regurgitation, it is unclear what factors contribute to persistent TV regurgitation following PVR. In particular, it is unknown whether PVR alone will reduce the right ventricular (RV) size and restore TV function or whether concomitant TV annuloplasty is required as well. Thirty-five patients were analyzed. Each patient underwent initial palliation of congenital pulmonary stenosis or tetralogy of Fallot, underwent subsequent PVR between 2002 and 2008, and had at least moderate TV regurgitation at the time of valve replacement. Serial echocardiograms were analyzed. Pulmonary and TV regurgitation, along with RV dilation and dysfunction, were scored (0, none; 1, mild; 2, moderate; 3, severe). RV volume and area were also calculated. Potential risk factors for persistent postoperative TV regurgitation were evaluated. One month following PVR, there was a significant reduction in pulmonary valve regurgitation (mean, 3 vs. 0.39; P < 0.0001) and TV regurgitation (mean, 2.33 vs. 1.3; P < 0.0001). There were also significant reductions in RV dilation, volume, and area. There were no significant further improvements in any of the parameters at 1 and 3 years. There was no difference in the degree of TV regurgitation postoperatively between those patients who underwent PVR alone and those who underwent concomitant tricuspid annuloplasty (mean, 1.29 vs. 1.31; P = 0.81). We conclude that following PVR, improvement in TV regurgitation and RV size occurs primarily in the first postoperative month. TV function improved to a similar degree with or without annuloplasty.

  2. Equivalences between nonuniform exponential dichotomy and admissibility

    NASA Astrophysics Data System (ADS)

    Zhou, Linfeng; Lu, Kening; Zhang, Weinian

    2017-01-01

    Relationship between exponential dichotomies and admissibility of function classes is a significant problem for hyperbolic dynamical systems. It was proved that a nonuniform exponential dichotomy implies several admissible pairs of function classes and conversely some admissible pairs were found to imply a nonuniform exponential dichotomy. In this paper we find an appropriate admissible pair of classes of Lyapunov bounded functions which is equivalent to the existence of nonuniform exponential dichotomy on half-lines R± separately, on both half-lines R± simultaneously, and on the whole line R. Additionally, the maximal admissibility is proved in the case on both half-lines R± simultaneously.

  3. Self-regulating valve

    DOEpatents

    Humphreys, D.A.

    1982-07-20

    A variable, self-regulating valve having a hydraulic loss coefficient proportional to a positive exponential power of the flow rate. The device includes two objects in a flow channel and structure which assures that the distance between the two objects is an increasing function of the flow rate. The range of spacing between the objects is such that the hydraulic resistance of the valve is an increasing function of the distance between the two objects so that the desired hydraulic loss coefficient as a function of flow rate is obtained without variation in the flow area.

  4. Ball valve safety screen

    SciTech Connect

    Bolding, B.H.

    1981-09-01

    A device for preventing unwanted objects from entering the ball assembly of a float collar or float shoe and otherwise damaging or plugging the valve mechanism therein is disclosed. The device comprises a screen constructed of expanded metal and rigidly affixed to the interior of the float collar or float shoe above the ball valve assembly. The screen portion is either mounted to the interior surface of the float collar sleeve by an annular structural member or mounted to a structural band which is partially embedded in the concrete portion of the float collar or casing guide shoe.

  5. Lightweight Valve Closes Duct Quickly

    NASA Technical Reports Server (NTRS)

    Fournier, Walter L.; Burgy, N. Frank

    1991-01-01

    Expanding balloon serves as lightweight emergency valve to close wide duct. Uninflated balloon stored in housing of duct. Pad resting on burst diaphragm protects balloon from hot gases in duct. Once control system triggers valve, balloon inflates rapidly to block duct. Weighs much less than does conventional butterfly, hot-gas, or poppet valve capable of closing duct of equal diameter.

  6. Lipomatous hamartoma of mitral valve.

    PubMed

    Bhat, Seetharama P S; Gowda, Girish S L; Chikkatur, Raghavendra; Nanjappa, Manjunath C

    2016-01-01

    Primary cardiac tumors are very rare, and tumors arising from cardiac valves are extremely rare. We present a case of lipomatous hamartoma of the mitral valve in a young female. This is the 6th case of lipomatous hamartoma of the mitral valve to be reported. We discuss the operative and histopathological findings.

  7. Transcatheter Valve-in-Valve: A Cautionary Tale.

    PubMed

    Luc, Jessica G Y; Shanks, Miriam; Tyrrell, Benjamin D; Welsh, Robert C; Butler, Craig R; Meyer, Steven R

    2016-09-01

    Transcatheter aortic valve replacement (TAVR) by valve-in-valve (VIV) implantation is an alternative treatment for high-risk patients with a degenerating aortic bioprosthesis. We present a case of transapical TAVR VIV with a 29-mm Edwards SAPIEN XT (ESV) (Edwards Lifesciences, Irvine, CA) into a 29-mm Medtronic Freestyle stentless bioprosthesis (Medtronic Inc, Minneapolis, MN) in which unanticipated dilatation of the Freestyle bioprosthesis resulted in intraprocedural embolization of the TAVR valve, necessitating urgent conversion to a conventional surgical aortic valve replacement (AVR). Our experience suggests that TAVR VIV with the 29-mm ESV in the setting of a degenerated 29-mm Freestyle stentless bioprosthesis must be undertaken with caution.

  8. Improved Merge Valve

    NASA Technical Reports Server (NTRS)

    George-Falvy, Dez

    1992-01-01

    Circumferential design combines compactness and efficiency. In remotely controlled valve, flow in tributary duct along circumference of primary duct merged with flow in primary duct. Flow in tributary duct regulated by variable throat nuzzle driven by worm gear. Design leak-proof, and most components easily fabricated on lathe.

  9. Aortic valve surgery - open

    MedlinePlus

    ... Saunders; 2012:chap 61. Otton CM, Bowow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Browse the Encyclopedia A.D.A.M., Inc. ...

  10. Valve for cryogenic service

    DOEpatents

    Worwetz, H.A.

    1975-09-02

    This patent relates to a valve for use with a liquefied gas at cryogenic temperatures in which a pair of joined knife edges are bellows controlled to contact an indium alloy seat in an annular slot when flow is to be stopped. The sealing alloy may be renewed by heating in situ. (auth)

  11. Poppet valve tester

    NASA Technical Reports Server (NTRS)

    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.

  12. Thermostatic Radiator Valve Evaluation

    SciTech Connect

    Dentz, Jordan; Ansanelli, Eric

    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.

  13. Valve for gas centrifuges

    DOEpatents

    Hahs, C.A.; Rurbage, C.H.

    1982-03-17

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

  14. Transcatheter aortic valve replacement

    MedlinePlus

    ... fully will restrict blood flow. This is called aortic stenosis. If there is also a leak, it is ... TAVR is used for people with severe aortic stenosis who aren't ... valve . In adults, aortic stenosis usually occurs due to calcium ...

  15. TUBE SHEARING VALVE

    DOEpatents

    Wilner, L.B.

    1960-05-24

    Explosive operated valves can be used to join two or more containers in fluid flow relationship, one such container being a sealed reservoir. The valve is most simply disposed by mounting it on the reservoir so thst a tube extends from the interior of the reservoir through the valve body, terminating at the bottom of the bore in a closed end; other containers may be similarly connected or may be open connected, as desired. The piston of the valve has a cutting edge at its lower end which shears off the closed tube ends and a recess above the cutting edge to provide a flow channel. Intermixing of the fluid being transferred with the explosion gases is prevented by a copper ring at the top of the piston which is force fitted into the bore at the beginning of the stroke. Although designed to avoid backing up of the piston at pressures up to 10,000 psi in the transferred fluid, proper operation is independent of piston position, once the tube ends were sheared.

  16. Valve operating and interrupting mechanism for internal combustion engine

    SciTech Connect

    Ajiki, Y.; Kajiwara, S.

    1986-09-23

    A valve operating mechanism is described for an internal combustion engine having a pair of intake or exhaust valves for each engine cylinder, comprising, a camshaft having high speed and low speed cams thereon, a rocker arm shaft having first second and third rocker arms pivotally mounted thereon in mutually adjacent relationship. The first and third rocker arms engage pair of valves, the first and second rocker arms engaging the low speed and high speed cams, respectively. The piston means in the rocker arms is electively shiftable between positions connecting the rocker arms for pivotal movement in unison and disconnecting the rocker arms for independent movement.

  17. Miniature Latching Valve

    NASA Technical Reports Server (NTRS)

    Johnson, A. David; Benson, Glendon M.

    2008-01-01

    A miniature latching valve has been invented to satisfy a need for an electrically controllable on/off pneumatic valve that is lightweight and compact and remains in the most recently commanded open or closed state when power is not supplied. The valve includes a poppet that is moved into or out of contact with a seat to effect closure or opening, respectively, of the flow path. Motion of the poppet is initiated by electrical heating of one of two opposing pairs of nickel/titanium shape-memory alloy (SMA) wires above their transition temperature: heated wires contract to their remembered length, applying tension to pull the poppet toward or away from the seat. A latch consisting mainly of a bistable Belleville washer (a conical spring) made of a hardened stainless steel operates between two stable positions corresponding to the fully closed or fully open state, holding the poppet in one of these positions when power is not applied to either pair of SMA wires. To obtain maximum actuation force and displacement, the SMA wires must be kept in tension. The mounting fixtures at the ends of the wires must support large tensile stresses without creating stress concentrations that would limit the fatigue lives of the wires. An earlier design provided for each wire to be crimped in a conical opening with a conical steel ferrule that was swaged into the opening to produce a large, uniformly distributed holding force. In a subsequent design, the conical ferrule was replaced with a larger crimped cylindrical ferrule depicted in the figure. A major problem in designing the valve was to protect the SMA wires from a bake-out temperature of 300 C. The problem was solved by incorporating the SMA wires into an actuator module that is inserted into a barrel of the valve body and is held in place by miniature clip rings.

  18. Multi-port valve assembly

    DOEpatents

    Guggenheim, S. Frederic

    1986-01-01

    A multi-port fluid valve apparatus is used to control the flow of fluids through a plurality of valves and includes a web, which preferably is a stainless steel endless belt. The belt has an aperture therethrough and is progressed, under motor drive and control, so that its aperture is moved from one valve mechanism to another. Each of the valve mechanisms comprises a pair of valve blocks which are held in fluid-tight relationship against the belt. Each valve block consists of a block having a bore through which the fluid flows, a first seal surrounding the bore and a second seal surrounding the first seal, with the distance between the first and second seals being greater than the size of the belt aperture. In order to open a valve, the motor progresses the belt aperture to where it is aligned with the two bores of a pair of valve blocks, such alignment permitting a flow of the fluid through the valve. The valve is closed by movement of the belt aperture and its replacement, within the pair of valve blocks, by a solid portion of the belt.

  19. Crossing the GEM Frontier: Graduate Admissions Professionals' Participation in Enrollment Management

    ERIC Educational Resources Information Center

    Campbell, C. Dean; Smith, Jahmaine

    2014-01-01

    Using qualitative inquiry and professional socialization as a framework to draw meaning from the work experiences of graduate admissions professionals, this project examines individual beliefs and organizational behaviors as they relate to enrollment management.

  20. Seasonality of hospital admissions for mental disorders in Hanoi, Vietnam

    PubMed Central

    Trang, Phan Minh; Rocklöv, Joacim; Giang, Kim Bao; Nilsson, Maria

    2016-01-01

    Background Some studies have shown a relationship between seasonality in weather patterns and depressive and behavioural disorders, especially in temperate climate regions. However, there is a lack of studies describing the seasonal patterns of hospital admissions for a variety of mental disorders in tropical and subtropical nations. The aim of this study has been to examine the relationship between seasons and daily hospital admissions for mental disorders in Hanoi, Vietnam. Designs A 5-year database (2008–2012) compiled by Hanoi Mental Hospital covering mental disorder admissions diagnosed by the International Classification of Diseases 10 was analysed. A negative binominal regression model was applied to estimate the associations between seasonality and daily hospital admissions for mental disorders, for all causes and for specific diagnoses. Results The summer season indicated the highest relative risk (RR=1.24, confidence interval (CI)=1.1–1.39) of hospital admission for mental disorders, with a peak in these cases in June (RR=1.46, CI=1.19–1.7). Compared to other demographic groups, males and the elderly (aged over 60 years) were more sensitive to seasonal risk changes. In the summer season, the RR of hospital visits among men increased by 26% (RR=1.26, CI=1.12–1.41) and among the elderly by 23% (RR=1.23, CI=1.03–1.48). Furthermore, when temperatures including minimum, mean, and maximum increased 1°C, the number of cases for mental disorders increased by 1.7%, 2%, and 2.1%, respectively. Conclusion The study results showed a correlation between hospital admission for mental disorders and season. PMID:27566716

  1. Heatwaves and Hospital Admissions for Mental Disorders in Northern Vietnam

    PubMed Central

    Trang, Phan Minh; Rocklöv, Joacim; Giang, Kim Bao; Kullgren, Gunnar; Nilsson, Maria

    2016-01-01

    Studies in high-income countries have shown an association between heatwaves and hospital admissions for mental disorders. It is unknown whether such associations exist in subtropical nations like Vietnam. The study aim was to investigate whether hospital admissions for mental disorders may be triggered, or exacerbated, by heat exposure and heatwaves, in a low- and middle-income country, Vietnam. For this, we used data from the Hanoi Mental Hospital over five years (2008–2012) to estimate the effect of heatwaves on admissions for mental disorders. A zero-inflated negative binomial regression model accounting for seasonality, time trend, days of week, and mean humidity was used to analyse the relationship. Heatwave events were mainly studied as periods of three or seven consecutive days above the threshold of 35°C daily maximum temperature (90th percentile). The study result showed heatwaves increased the risk for admission in the whole group of mental disorders (F00-79) for more persistent heatwaves of at least 3 days when compared with non-heatwave periods. The relative risks were estimated at 1.04 (0.95–1.13), 1.15 (1.005–1.31), and 1.36 (1–1.90) for a one-, three- and seven-day heatwave, respectively. Admissions for mental disorders increased among men, residents in rural communities, and the elderly population during heatwaves. The groups of organic mental disorders, including symptomatic illnesses (F0-9) and mental retardation (F70-79), had increased admissions during heatwaves. The findings are novel in their focus on heatwave impact on mental diseases in a population habituating in a subtropical low- and middle-income country characterized by rapid epidemiological transitions and environmental changes. PMID:27195473

  2. Transformation of admission interview to documentation for nursing practice.

    PubMed

    Højskov, Ida E; Glasdam, Stinne

    2014-09-01

    The admission interview is usually the first structured meeting between patient and nurse. The interview serves as the basis for personalised nursing and care planning and is the starting point for the clinic's documentation of the patient and his course of treatment. In this way, admission interviews constitute a basis for reporting by each nurse on the patient to nursing colleagues. This study examined how, by means of the admission interview, nurses constructed written documentation of the patient and his course of treatment for use by fellow nurses. A qualitative case study inspired by Ricoeur was conducted and consisted of five taped admission interviews, along with the written patient documentation subsequently worked out by the nurse. The findings were presented in four constructed themes: Admission interviews are the nurse's room rather than the patient's; Information on a surgical object; The insignificant but necessary contact; and Abnormalities must be medicated. It is shown how the nurse's documentation was based on the admission interview, the medical record details on the patient (facts that are essential to know in relation to disease and treatment), as well as the nurse's preconception of how to live a good life, with or without disease. Often, the patient tended to become an object in the nurse's report. It is concluded that in practice, the applied documentation system, VIPS, comes to act as the framework for what is important to the nurse to document rather than a tool that enables her to document what is important to the individual patient and his special circumstances and encounter with the health system.

  3. Bicuspid aortic valve disease: systematic review and meta-analysis of surgical aortic valve repair

    PubMed Central

    Naci, Huseyin; Pender, Sarah; Kuehne, Titus; Kelm, Marcus

    2016-01-01

    Aortic valve repair is still emerging, and its role in the treatment of bicuspid aortic valve disease (BAVD) is not yet fully understood. Our objective is to synthesise available evidence on outcomes after surgical aortic valve repair in patients with BAVD. We conducted a systematic review of clinical studies using prespecified methods for searching, identifying and selecting eligible studies in 4 databases, and synthesising results (PROSPERO 2014:CRD42014014415). 2 researchers independently reviewed full-text articles and extracted data. The results of included studies were quantitatively synthesised in frequentist meta-analyses. We included 11 aortic valve repair studies or study arms with a total of 2010 participants. Pooled estimates for the proportion of patients surviving at 30 days, 1 year, 5 years and 10 years were 0.995 (95% CI 0.991 to 0.995), 0.994 (0.989 to 0.999), 0.945 (0.898 to 0.993) and 0.912 (0.845 to 0.979), respectively. The pooled proportion of late deaths from valve-related causes was 0.008 (0.000 to 0.019) at a mean follow-up of 3.5 years. Proportion of patients with valve-related reinterventions was 0.075 (0.037 to 0.113) at a mean follow-up of 3.9 years, and the linearised reintervention rate was 1.3 (0.7 to 1.9) per 100 patient-years. Outcome reporting was insufficient to pool the results for a number of predefined outcomes. In conclusion, existing evidence on aortic valve repair in BAVD is limited to mostly small case series, case–control and small retrospective cohort studies. Despite the low quality, available evidence suggests favourable survival outcomes after aortic valve repair in selected patients with BAVD. Valve-related reinterventions at follow-up are common in all patients undergoing repair surgery. PMID:28008357

  4. Micro-valve pump light valve display

    DOEpatents

    Lee, Yee-Chun

    1993-01-01

    A flat panel display incorporates a plurality of micro-pump light valves (MLV's) to form pixels for recreating an image. Each MLV consists of a dielectric drop sandwiched between substrates, at least one of which is transparent, a holding electrode for maintaining the drop outside a viewing area, and a switching electrode from accelerating the drop from a location within the holding electrode to a location within the viewing area. The sustrates may further define non-wetting surface areas to create potential energy barriers to assist in controlling movement of the drop. The forces acting on the drop are quadratic in nature to provide a nonlinear response for increased image contrast. A crossed electrode structure can be used to activate the pixels whereby a large flat panel display is formed without active driver components at each pixel.

  5. Micro-valve pump light valve display

    DOEpatents

    Yeechun Lee.

    1993-01-19

    A flat panel display incorporates a plurality of micro-pump light valves (MLV's) to form pixels for recreating an image. Each MLV consists of a dielectric drop sandwiched between substrates, at least one of which is transparent, a holding electrode for maintaining the drop outside a viewing area, and a switching electrode from accelerating the drop from a location within the holding electrode to a location within the viewing area. The sustrates may further define non-wetting surface areas to create potential energy barriers to assist in controlling movement of the drop. The forces acting on the drop are quadratic in nature to provide a nonlinear response for increased image contrast. A crossed electrode structure can be used to activate the pixels whereby a large flat panel display is formed without active driver components at each pixel.

  6. Performance of Bovine Pericardial Valves in the Pulmonary Position

    PubMed Central

    Shinkawa, Takeshi; Anagnostopoulos, Petros V.; Johnson, Natalie C.; Watanabe, Naruhito; Sapru, Anil; Azakie, Anthony

    2017-01-01

    Background The purpose of this study is to determine the outcome and performance of bovine pericardial valves in the pulmonary position. Methods This is a retrospective review of all patients with congenital heart disease who had pulmonary valve replacement using a bovine pericardial valve from 2002 to 2009 at a single institution. Results There were 73 consecutive patients, with a median age of 17.3 years (range, 2.1 to 64.4). Their diagnosis was tetralogy of Fallot (n = 47), pulmonary stenosis (n = 11), or other (n = 15). Sixty-nine patients had 91 previous surgical procedures. The mean time from last surgery was 19.9 ± 11.6 years. Forty-three patients had concomitant surgical procedures. There were no perioperative deaths. Clinical follow-up was available in 68 patients (93%). There were no late deaths, and all patients were in New York Heart Association functional class I during a median follow-up period of 2.6 years (range, 0.2 to 8.0). One patient had endocarditis necessitating valve removal 2 years after surgery. Freedom from pulmonary valve reoperation was 100%, 97.7%, and 97.7% at 1, 3, and 5 years, respectively (95% confidence interval: 93.2% to 100%). Mean pulmonary valve gradient at follow-up was 19 ± 14 mm Hg. Degree of pulmonary insufficiency was less than moderate in 62 patients, moderate in 4, and more than moderate in 2. Freedom from moderate-severe or severe pulmonary insufficiency was 97.7%, 89.1%, and 89.1% at 1, 3, and 5 years, respectively (5-year 95% confidence interval: 77.0% to 100%). Conclusions Pulmonary valve replacement using a bovine pericardial valve can be accomplished with low perioperative morbidity and favorable midterm outcomes. Further follow-up is necessary to evaluate the long-term performance of bovine pericardial valves in the pulmonary position. PMID:20868832

  7. Management of Prolonged Pulmonary Air Leaks With Endobronchial Valve Placement

    PubMed Central

    Doelken, Peter; Pupovac, Stevan; Ata, Ashar; Fabian, Tom

    2016-01-01

    Background: Prolonged pulmonary air leaks (PALs) are associated with increased morbidity and extended hospital stay. We sought to investigate the role of bronchoscopic placement of 1-way valves in treating this condition. Methods: We queried a prospectively maintained database of patients with PAL lasting more than 7 days at a tertiary medical center. Main outcome measures included duration of chest tube placement and hospital stay before and after valve deployment. Results: Sixteen patients were eligible to be enrolled from September 2012 through December 2014. One patient refused to give consent, and in 4 patients, the source of air leak could not be identified with bronchoscopic balloon occlusion. Eleven patients (9 men; mean age, 65 ± 15 years) underwent bronchoscopic valve deployment. Eight patients had postoperative PAL and 3 had a secondary spontaneous pneumothorax. The mean duration of air leak before valve deployment was 16 ± 12 days, and the mean number of implanted valves was 1.9 (median, 2). Mean duration of hospital stay before and after valve deployment was 18 and 9 days, respectively (P = .03). Patients who had more than a 50% decrease in air leak on digital monitoring had the thoracostomy tube removed within 3–6 days. There were no procedural complications related to deployment or removal of the valves. Conclusions: Bronchoscopic placement of 1-way valves is a safe procedure that could help manage patients with prolonged PAL. A prospective randomized trial with cost-efficiency analysis is necessary to better define the role of this bronchoscopic intervention and demonstrate its effect on air leak duration. PMID:27647978

  8. Valve for controlling solids flow

    DOEpatents

    Staiger, M.D.

    1982-09-29

    A valve for controlling the flow of solids comprises a vessel having an overflow point, an inlet line for discharging solids into the vessel positioned within the vessel such that the inlet line's discharge point is lower than the vessel's overflow point, and means for introducing a fluidizing fluid into the vessel. The fluidizing fluid fluidizes the solids within the vessel so that they overflow at the vessel's overflow point. For the removal of nuclear waste product the vessel may be placed within a sealed container having a bottom connected transport line for transporting the solids to storage or other sites. The rate of solids flow is controlled by the flow rate of the fluidizing fluid and by V-notch weirs of different sizes spaced about the top of the vessel.

  9. Ventriculopleural shunting with new technology valves.

    PubMed

    Martínez-Lage, J F; Torres, J; Campillo, H; Sanchez-del-Rincón, I; Bueno, F; Zambudio, G; Poza, M

    2000-12-01

    Ventriculoperitoneal shunting constitutes the standard procedure for draining cerebrospinal fluid (CSF) in children with hydrocephalus. Ventriculoatrial and ventriculopleural shunting are alternative methods of CSF drainage, which have gained less acceptance. Ventriculopleural shunts are seldom used owing to justified fears of pneumothorax and symptomatic effusions of CSF. The addition of an antisiphon device to standard shunt systems seems to have prevented CSF pleural effusion. From 1988 to 1998, we treated each of six hydrocephalic children with a ventriculopleural shunt. In five cases we used new-technology valves designed to prevent the effects of siphoning with current differential pressure valves. Peritoneal adhesions, recent peritonitis, ascites, and obstruction of a previous ventriculoatrial shunt were the indications for pleural shunting. After a mean follow-up period of 2.5 years all shunts were functioning adequately. Only one patient showed transient symptoms of CSF overdrainage, which were corrected by up-grading the valve setting with the magnet. A late death was unrelated to the pleural shunting procedure. The use of valves of a new design designed to prevent overdrainage seems to account for the satisfactory outcomes observed in this series. We suggest that ventriculopleural shunting should be considered as the preferred alternative to peritoneal drainage in children with intra-abdominal adhesions or with a history of recent peritoneal infection.

  10. 45 CFR 2555.300 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 4 2014-10-01 2014-10-01 false Admission. 2555.300 Section 2555.300 Public... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 2555.300 Admission. (a) General. No..., by any recipient to which §§ 2555.300 through 2555.310 apply, except as provided in §§ 2555.225...

  11. 6 CFR 17.300 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 6 Domestic Security 1 2012-01-01 2012-01-01 false Admission. 17.300 Section 17.300 Domestic... in Admission and Recruitment Prohibited § 17.300 Admission. (a) General. No person shall, on the... which §§ 17.300 through 17.310 apply, except as provided in §§ 17.225 and 17.230. (b)...

  12. 40 CFR 5.300 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 1 2011-07-01 2011-07-01 false Admission. 5.300 Section 5.300... in Admission and Recruitment Prohibited § 5.300 Admission. (a) General. No person shall, on the basis... which §§ 5.300 through §§ 5.310 apply, except as provided in §§ 5.225 and 5.230. (b)...

  13. 15 CFR 8a.300 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Admission. 8a.300 Section 8a.300... in Admission and Recruitment Prohibited § 8a.300 Admission. (a) General. No person shall, on the... which §§ 8a.300 through §§ 8a.310 apply, except as provided in §§ 8a.225 and §§ 8a.230. (b)...

  14. 45 CFR 2555.300 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 4 2011-10-01 2011-10-01 false Admission. 2555.300 Section 2555.300 Public... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 2555.300 Admission. (a) General. No..., by any recipient to which §§ 2555.300 through 2555.310 apply, except as provided in §§ 2555.225...

  15. 14 CFR 1253.300 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Admission. 1253.300 Section 1253.300... in Admission and Recruitment Prohibited § 1253.300 Admission. (a) General. No person shall, on the... which §§ 1253.300 through §§ 1253.310 apply, except as provided in §§ 1253.225 and §§ 1253.230....

  16. Prominent Eustachian Valve in Newborns: A Report of Four Cases

    PubMed Central

    Gad, Ashraf; Mannan, Javed; Chhabra, Manoj; Zhang, Xi Xiao Yang; Narula, Pramod; Hoang, Danthanh

    2015-01-01

    The Eustachian valve (EV) is an embryological remnant of the inferior vena cava that during fetal life helps divert oxygenated blood from the IVC toward the foramen ovale to escape the pulmonary circulation. This remnant usually regresses after birth and is considered a benign finding in the majority of cases. However, EV can lead to complications in the neonatal period or later in life. In this short case series, we present four newborn infants with prominent EV who were symptomatic after birth and required admission to the neonatal intensive care unit. PMID:26929867

  17. Injection pump with radially mounted spill control valve

    SciTech Connect

    Djordjevic, I.

    1987-05-26

    This patent describes a rotary fuel injection pump for an internal combustion engine,. The method comprises: a housing, a rotor rotatable in the housing, a charge pump having radially extending plunger bores in the rotor and a plunger pump for each plunger bore having a pumping plunger reciprocable in the bore. The pumping plunger has outward fuel tank strokes and inward fuel delivery strokes for supplying high pressure charges of fuel for fuel injection. A cam ring surrounds the rotor and is engageable with the plunger pumps to reciprocate the plungers as the rotor rotates. A spill control mechanism has spill valve means connected to the charge pump for spill control of the high pressure charge of fuel. The improvement consists of the spill valve means which comprises at least one rotary spill valve having a valve bore in the rotor oriented transversely to the axis of the rotor and connected to the charge pump through pump passage means and a rotary spill valve member rotatably mounted within the valve bore; and the spill control mechanism.

  18. Temporal variation in major trauma admissions

    PubMed Central

    Kieffer, WKM; Michalik, DV; Gallagher, K; McFadyen, I; Bernard, J; Rogers, BA

    2016-01-01

    Introduction Trauma is a significant cause of morbidity and mortality in the UK. Since the inception of the trauma networks, little is known of the temporal pattern of trauma admissions. Methods Trauma Audit and Research Network data for 1 April 2011 to 31 March 2013 were collated from two large major trauma centres (MTCs) in the South East of England: Brighton and Sussex University Hospitals NHS Trust (BSUH) and St George's University Hospitals NHS Foundation Trust (SGU). The number of admissions and the injury severity score by time of admission, by weekdays versus weekend and by month/season were analysed. Results There were 1,223 admissions at BSUH and 1,241 at SGU. There was significant variation by time of admission; there were more admissions in the afternoons (BSUH p<0.001) and evenings (SGU p<0.001). There were proportionally more admissions at the weekends than on weekdays (BSUH p<0.001, SGU p=0.028). There was significant seasonal variation in admissions at BSUH (p<0.001) with more admissions in summer and autumn. No significant seasonal variation was observed at SGU (p=0.543). Conclusions The temporal patterns observed were different for each MTC with important implications for resource planning of trauma care. This study identified differing needs for different MTCs and resource planning should be individualised to the network. PMID:26741676

  19. Fast acting multiple element valve

    DOEpatents

    Yang, Jefferson Y. S.; Wada, James M.

    1991-01-01

    A plurality of slide valve elements having plural axial-spaced annular parts and an internal slide are inserted into a bulkhead in a fluid conduit from a downstream side of the bulkhead, locked in place by a bayonet coupling and set screw, and project through the bulkhead into the upstream conduit. Pneumatic lines connecting the slide valve element actuator to pilot valves are brought out the throat of the valve element to the downstream side. Pilot valves are radially spaced around the exterior of the valve to permit the pneumatic lines to be made identical, thereby to minimize adverse timing tolerances in operation due to pressure variations. Ring manifolds surround the valve adjacent respective pilot valve arrangements to further reduce adverse timing tolerances due to pressure variations, the manifolds being directly connected to the respective pilot valves. Position sensors are provided the valve element slides to signal the precise time at which a slide reaches or passes through a particular point in its stroke to initiate a calibrated timing function.

  20. Weather, season, and daily stroke admissions in Hong Kong

    NASA Astrophysics Data System (ADS)

    Goggins, William B.; Woo, Jean; Ho, Suzanne; Chan, Emily Y. Y.; Chau, P. H.

    2012-09-01

    Previous studies examining daily temperature and stroke incidence have given conflicting results. We undertook this retrospective study of all stroke admissions in those aged 35 years old and above to Hong Kong public hospitals from 1999 through 2006 in order to better understand the effects of meteorological conditions on stroke risk in a subtropical setting. We used Poisson Generalized Additive Models with daily hemorrhagic (HS) and ischemic stroke (IS) counts separately as outcomes, and daily mean temperature, humidity, solar radiation, rainfall, air pressure, pollutants, flu consultation rates, day of week, holidays, time trend and seasonality as predictors. Lagged effects of temperature, humidity and pollutants were also considered. A total of 23,457 HS and 107,505 IS admissions were analyzed. Mean daily temperature had a strong, consistent, negative linear association with HS admissions over the range (8.2-31.8°C) observed. A 1°C lower average temperature over the same day and previous 4 days (lags 0-4) being associated with a 2.7% (95% CI: 2.0-3.4%, P < .0.0001) higher admission rate after controlling for other variables. This association was stronger among older subjects and females. Higher lag 0-4 average change in air pressure from previous day was modestly associated with higher HS risk. The association between IS and temperature was weaker and apparent only below 22°C, with a 1°C lower average temperature (lags 0-13) below this threshold being associated with a 1.6% (95% CI:1.0-2.2%, P < 0.0001) higher IS admission rate. Pollutant levels were not associated with HS or IS. Future studies should examine HS and IS risk separately.

  1. Fast-acting valve and uses thereof

    DOEpatents

    Meyer, J.A.

    1980-05-16

    A very fast acting valve capable of producing a very well-defined plug of gas suitable for filling a theta pinch vacuum vessel is given. The valve requires no springs, instead being stopped mainly by a nonlinear force. Thus, the valve is not subject to bouncing; and the ratio of the size of the valve housing to the size of the valve stem is smaller than it would be if springs were needed to stop the valve stem. Furthermore, the valve can be used for thousands of valve firings with no apparent valve damage.

  2. Fast-acting valve and uses thereof

    DOEpatents

    Meyer, James A.

    1982-01-01

    A very fast acting valve capable of producing a very well-defined plug of gas suitable for filling a theta pinch vacuum vessel is given. The valve requires no springs, instead being stopped mainly by a nonlinear force. Thus, the valve is not subject to bouncing; and the ratio of the size of the valve housing to the size of the valve stem is smaller than it would be if springs were needed to stop the valve stem. Furthermore, the valve can be used for thousands of valve firings with no apparent valve damage.

  3. Rotary multiposition valve

    DOEpatents

    Barclay, John A.; Dyson, Jack E.

    1985-01-01

    The disclosure is directed to a rotary multiposition valve for selectively directing the flow of a fluid through a plurality of paths. The valve comprises an inner member and a hollow housing with a row of ducts on its outer surface. The ducts are in fluid communication with the housing. An engaging section of the inner member is received in the housing. A seal divides the engaging section into a hollow inlet segment and a hollow outlet segment. A plurality of inlet apertures are disposed in the inlet segment and a plurality of outlet apertures are disposed in the outlet segment. The inlet apertures are disposed in a longitudinally and radially spaced-apart pattern that can be a helix. The outlet apertures are disposed in a corresponding pattern. As the inner member is rotated, whenever an inlet aperture overlaps one of the ducts, the corresponding outlet aperture overlaps a different duct, thus forming a fluid pathway.

  4. Stemless ball valve

    NASA Technical Reports Server (NTRS)

    Burgess, Kevin (Inventor); Yakos, David (Inventor); Walthall, Bryan (Inventor)

    2011-01-01

    A stemless ball valve comprising two flanges and a ball with a channel, two axis pins and two travel pins. One end of each axis and travel pin is fixedly attached to the ball, and the other end of each axis pin is lodged into a notch in the first or second flange such that the axis pin is allowed to rotate in the notch. The guide sleeve comprises two channels, and one end of each travel pin is situated within one of the two channels in the guide sleeve. An outer magnetic cartridge causes the inner magnetic cartridge and guide sleeve to rotate, and when the guide sleeve rotates, the travel pins move up and down within the channels in the guide sleeve. The movement of the travel pins within the channels in the guide sleeve causes the ball to rotate, thereby opening and closing the ball valve.

  5. Rotary multiposition valve

    DOEpatents

    Barclay, J.A.; Dyson, J.E.

    1984-04-06

    The disclosure is directed to a rotary multiposition valve for selectively directing the flow of a fluid through a plurality of paths. The valve comprises an inner member and a hollow housing with a row of ducts on its outer surface. The ducts are in fluid communication with the housing. An engaging section of the inner member is received in the housing. A seal divides the engaging section into a hollow inlet segment and a hollow outlet segment. A plurality of inlet apertures are disposed in the inlet sgegment and a plurality of outlet apertures are disposed in the outlet segment. The inlet apertures are disposed in a longitudinally and radially spaced-apart pattern that can be a helix. The outlet apertures are disposed in a corresponding pattern. As the inner member is rotated, whenever an inlet aperture overlaps one of the ducts, the corresponding outlet aperture overlaps a different duct, thus forming a fluid pathway.

  6. Bioprosthetic mitral valve dysfunction due to native valve preserving procedure.

    PubMed

    Matsuno, Yukihiro; Mori, Yoshio; Umeda, Yukio; Takiya, Hiroshi

    2016-03-01

    Mitral valve replacement with preservation of the mitral leaflets and subvalvular apparatus is considered to maintain left ventricular geometry and function and reduce the risk of myocardial rupture. However, the routine use of this technique may lead to early complications such as left ventricular outflow tract obstruction and even mitral inflow obstruction, requiring reoperation. We describe a rare case of bioprosthetic mitral valve dysfunction caused by a native valve preserving procedure.

  7. Performance Characteristics of an Isothermal Freeze Valve

    SciTech Connect

    Hailey, A.E.

    2001-08-22

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

  8. Slow opening valve. [valve design for shuttle portable oxygen system

    NASA Technical Reports Server (NTRS)

    Drapeau, D. F. (Inventor)

    1984-01-01

    A valve control is described having a valve body with an actuator stem and a rotating handle connected to the actuator stem by a differential drive mechanism which, during uniform movement of the handle in one direction, initially opens the valve at a relatively slow rate and, thereafter, complete the valve movement at a substantially faster rate. A series of stop rings are received about the body in frictional abutting relationship and serially rotated by the handle to uniformly resist handle movement independently of the extent of handle movement.

  9. Atmospheric pollutants and hospital admissions due to pneumonia in children

    PubMed Central

    Negrisoli, Juliana; Nascimento, Luiz Fernando C.

    2013-01-01

    OBJECTIVE: To analyze the relationship between exposure to air pollutants and hospitalizations due to pneumonia in children of Sorocaba, São Paulo, Brazil. METHODS: Time series ecological study, from 2007 to 2008. Daily data were obtained from the State Environmental Agency for Pollution Control for particulate matter, nitric oxide, nitrogen dioxide, ozone, besides air temperature and relative humidity. The data concerning pneumonia admissions were collected in the public health system of Sorocaba. Correlations between the variables of interest using Pearson cofficient were calculated. Models with lags from zero to five days after exposure to pollutants were performed to analyze the association between the exposure to environmental pollutants and hospital admissions. The analysis used the generalized linear model of Poisson regression, being significant p<0.05. RESULTS: There were 1,825 admissions for pneumonia, with a daily mean of 2.5±2.1. There was a strong correlation between pollutants and hospital admissions, except for ozone. Regarding the Poisson regression analysis with the multi-pollutant model, only nitrogen dioxide was statistically significant in the same day (relative risk - RR=1.016), as well as particulate matter with a lag of four days (RR=1.009) after exposure to pollutants. CONCLUSIONS: There was an acute effect of exposure to nitrogen dioxide and a later effect of exposure to particulate matter on children hospitalizations for pneumonia in Sorocaba. PMID:24473956

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

    NASA Technical Reports Server (NTRS)

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

    1943-01-01

    Report presents the results of a thermocouple installed in the crown of a sodium-cooled exhaust valve. The valve was tested in an air-cooled engine cylinder and valve temperatures under various engine operating conditions were determined. A temperature of 1337 degrees 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 r.p.m. 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.

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

    NASA Technical Reports Server (NTRS)

    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.

  12. Coronary Ostial Stenosis after Aortic Valve Replacement

    PubMed Central

    Ziakas, Antonios G.; Economou, Fotios I.; Charokopos, Nicholas A.; Pitsis, Antonios A.; Parharidou, Despina G.; Papadopoulos, Thomas I.; Parharidis, Georgios E.

    2010-01-01

    Coronary ostial stenosis is a rare but potentially serious sequela after aortic valve replacement. It occurs in the left main or right coronary artery after 1% to 5% of aortic valve replacement procedures. The clinical symptoms are usually severe and may appear from 1 to 6 months postoperatively. Although the typical treatment is coronary artery bypass grafting, patients have been successfully treated by means of percutaneous coronary intervention. Herein, we present the cases of 2 patients in whom coronary ostial stenosis developed after aortic valve replacement. In the 1st case, a 72-year-old man underwent aortic valve replacement and bypass grafting of the saphenous vein to the left anterior descending coronary artery. Six months later, he experienced a non-ST-segment-elevation myocardial infarction. Coronary angiography revealed a critical stenosis of the right coronary artery ostium. In the 2nd case, a 78-year-old woman underwent aortic valve replacement and grafting of the saphenous vein to an occluded right coronary artery. Four months later, she experienced unstable angina. Coronary angiography showed a critical left main coronary artery ostial stenosis and occlusion of the right coronary artery venous graft. In each patient, we performed percutaneous coronary intervention and deployed a drug-eluting stent. Both patients were asymptomatic on 6-to 12-month follow-up. We attribute the coronary ostial stenosis to the selective ostial administration of cardioplegic solution during surgery. We conclude that retrograde administration of cardioplegic solution through the coronary sinus may reduce the incidence of postoperative coronary ostial stenosis, and that stenting may be an efficient treatment option. PMID:20844624

  13. Investigation into the reasons for preventable drug related admissions to a medical admissions unit: observational study

    PubMed Central

    Howard, R; Avery, A; Howard, P; Partridge, M

    2003-01-01

    Objective: To describe the drugs and types of medicine management problems most frequently associated with preventable drug related admissions to an acute medical admissions unit. Design: Observation study. Setting: Medical admissions unit in a teaching hospital in Nottingham, UK. Participants: 4093 patients seen by pharmacists on the medical admissions unit between 1 January and 30 June 2001. Main outcome measures: Proportion of admissions that were drug related and preventable, classification of the underlying causes of preventable drug related admissions, and identification of drugs most commonly associated with preventable drug related admissions. Results: Of the admissions seen by pharmacists, 265 (6.5%) were judged to be drug related and 178 (67%) of these were judged to be preventable. Preventable admissions were mainly due to problems with prescribing (63 cases (35%)), monitoring (46 cases (26%)), and adherence to medication (53 cases (30%)). The drugs most commonly implicated were NSAIDs, antiplatelets, antiepileptics, hypoglycaemics, diuretics, inhaled corticosteroids, cardiac glycosides, and beta-blockers. Conclusions: Potentially preventable drug related morbidity was associated with 4.3% of admissions to a medical admissions unit. In 91% of cases these admissions were related to problems with either prescribing, monitoring, or adherence. PMID:12897361

  14. Sequenced drive for rotary valves

    DOEpatents

    Mittell, Larry C.

    1981-01-01

    A sequenced drive for rotary valves which provides the benefits of applying rotary and linear motions to the movable sealing element of the valve. The sequenced drive provides a close approximation of linear motion while engaging or disengaging the movable element with the seat minimizing wear and damage due to scrubbing action. The rotary motion of the drive swings the movable element out of the flowpath thus eliminating obstruction to flow through the valve.

  15. Semi-active compressor valve

    DOEpatents

    Brun, Klaus; Gernentz, Ryan S.

    2010-07-27

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

  16. Streamline coal slurry letdown valve

    DOEpatents

    Platt, Robert J.; Shadbolt, Edward A.

    1983-01-01

    A streamlined coal slurry letdown valve is featured which has a two-piece throat comprised of a seat and seat retainer. The two-piece design allows for easy assembly and disassembly of the valve. A novel cage holds the two-piece throat together during the high pressure letdown. The coal slurry letdown valve has long operating life as a result of its streamlined and erosion-resistance surfaces.

  17. Streamline coal slurry letdown valve

    DOEpatents

    Platt, R.J.; Shadbolt, E.A.

    1983-11-08

    A streamlined coal slurry letdown valve is featured which has a two-piece throat comprised of a seat and seat retainer. The two-piece design allows for easy assembly and disassembly of the valve. A novel cage holds the two-piece throat together during the high pressure letdown. The coal slurry letdown valve has long operating life as a result of its streamlined and erosion-resistance surfaces. 5 figs.

  18. 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

    PubMed Central

    Wöhrle, Jochen; Gonska, Birgid; Rodewald, Christoph; Seeger, Julia; Scharnbeck, Dominik; Rottbauer, Wolfgang

    2016-01-01

    Aims The third generation Edwards Sapien 3 (Edwards Lifesciences Inc., Irvine, California) system was optimized to reduce residual aortic regurgitation and vascular complications. Methods and Results 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. Conclusions 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. Trial Registration ClinicalTrials.gov NCT02162069 PMID:27003573

  19. Durability of pyrolytic carbon-containing heart valve prostheses.

    PubMed

    Schoen, F J; Titus, J L; Lawrie, G M

    1982-09-01

    To assess abrasive wear of mechanical valve prostheses containing pyrolytic carbon components, we recovered at necropsy or surgery and analyzed by scanning electron microscopy and surface profilometry eight prostheses. Seven were implanted for 30-85 (mean 50 months. Valves included DeBakey aortic (2), DeBakey mitral (1), Beall mitral (2), Bjork-Shiley aortic (1), Cooley-Cutter mitral (1), and Lillehei-Kaster (L-K) tricuspid (1). All carbon occluders had undetectable wear. Carbon cage struts had a superficial burnish. Metallic struts had insignificant wear marks. In contrast, a Teflon Beall Model 104 valve implanted for 34 days and similarly analyzed had considerable material loss from the cage struts. This study suggests that clinically important abrasive wear will not be a late complication of cardiac valve replacement with pyrolytic carbon prostheses.

  20. 28 CFR 54.300 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Administration DEPARTMENT OF JUSTICE (CONTINUED) NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 54.300 Admission. (a) General. No person shall, on the basis of sex, be...

  1. 14 CFR 1253.300 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex... basis of sex, be denied admission, or be subjected to discrimination in admission, by any recipient...

  2. Lexical Profiles of Thailand University Admission Tests

    ERIC Educational Resources Information Center

    Cherngchawano, Wirun; Jaturapitakkul, Natjiree

    2014-01-01

    University Admission Tests in Thailand are important documents which reflect Thailand's education system. To study at a higher education level, all students generally need to take the University Admission Tests designed by the National Institute of Educational Testing Service (NIETS). For the English test, vocabulary and reading comprehension is…

  3. 7 CFR 15a.21 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 1 2014-01-01 2014-01-01 false Admission. 15a.21 Section 15a.21 Agriculture Office of the Secretary of Agriculture EDUCATION PROGRAMS OR ACTIVITIES RECEIVING OR BENEFITTING FROM FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited §...

  4. 7 CFR 15a.21 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 1 2011-01-01 2011-01-01 false Admission. 15a.21 Section 15a.21 Agriculture Office of the Secretary of Agriculture EDUCATION PROGRAMS OR ACTIVITIES RECEIVING OR BENEFITTING FROM FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited §...

  5. 45 CFR 618.300 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on... shall, on the basis of sex, be denied admission, or be subjected to discrimination in admission, by...

  6. 45 CFR 618.300 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on... shall, on the basis of sex, be denied admission, or be subjected to discrimination in admission, by...

  7. 45 CFR 618.300 - Admission.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on... shall, on the basis of sex, be denied admission, or be subjected to discrimination in admission, by...

  8. 7 CFR 503.2 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 6 2011-01-01 2011-01-01 false Admission. 503.2 Section 503.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON PLUM ISLAND ANIMAL DISEASE CENTER § 503.2 Admission. No person will be admitted to PIADC,...

  9. 7 CFR 503.2 - Admission.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 6 2013-01-01 2013-01-01 false Admission. 503.2 Section 503.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON PLUM ISLAND ANIMAL DISEASE CENTER § 503.2 Admission. No person will be admitted to PIADC,...

  10. 7 CFR 503.2 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Admission. 503.2 Section 503.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON PLUM ISLAND ANIMAL DISEASE CENTER § 503.2 Admission. No person will be admitted to PIADC,...

  11. 7 CFR 503.2 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 6 2014-01-01 2014-01-01 false Admission. 503.2 Section 503.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON PLUM ISLAND ANIMAL DISEASE CENTER § 503.2 Admission. No person will be admitted to PIADC,...

  12. Unethical Admissions: Academic Integrity in Question.

    PubMed

    Ansah, Richard Hannis; Aikhuele, Daniel O; Yao, Liu

    2016-11-28

    The increasing unethical practices of graduates' admissions have heightened concerns about the integrity of the academy. This article informs this important subject that affects the students, admission systems, and the entire scientific community, thus, representing an approach against scholarly black market activities including falsified documents and unethical practices by consultants and students' recruitment agencies.

  13. 7 CFR 503.2 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 6 2012-01-01 2012-01-01 false Admission. 503.2 Section 503.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON PLUM ISLAND ANIMAL DISEASE CENTER § 503.2 Admission. No person will be admitted to PIADC,...

  14. Profile in Action: Linking Admission and Retention

    ERIC Educational Resources Information Center

    Cortes, Carla M.

    2013-01-01

    A profile-oriented retention strategy embraces the admission process as a powerful lever in improving retention and completion rates and recognizes that the student profile can be shaped by changes in admission policies or priorities--even within the current market position of the institution. In addition, the student body can be oriented toward…

  15. Grade Inflation and Law School Admissions

    ERIC Educational Resources Information Center

    Wongsurawat, Winai

    2008-01-01

    Purpose: The purpose of this paper is to evaluate the evidence on whether grade inflation has led to an increasing emphasis on standardized test scores as a criterion for law school admissions. Design/methodology/approach: Fit probabilistic models to admissions data for American law schools during the mid to late 1990s, a period during which…

  16. Strategies and Trends in Admissions Research

    ERIC Educational Resources Information Center

    Fincher, Cameron

    1975-01-01

    Noting that the technical service rendered by the national testing agencies may be an undesirable tradeoff for the active involvement of admissions workers in admissions research, the author suggests that the use of decision theory, quasi-actuarial assessment, quasi-experimental design, and program evaluation strategies would place admissions…

  17. Alphabetical Order Effects in School Admissions

    ERIC Educational Resources Information Center

    Jurajda, Štepán; Münich, Daniel

    2016-01-01

    If school admission committees use alphabetically sorted lists of applicants in their evaluations, one's position in the alphabet according to last name initial may be important in determining access to selective schools. Jurajda and Münich (2010) "Admission to Selective Schools, Alphabetically". "Economics of Education…

  18. Why Do We Stay in Admissions?

    ERIC Educational Resources Information Center

    Piersol, Marion Kandel; And Others

    1993-01-01

    Admission counselors (n=200) completed surveys about employment, title, on-the-job training, travel, and availability and satisfaction with certain responsibilities. Most satisfying admission responsibilities were program organization and implementation, applicant review and decision, and formal presentations. Least satisfying were telemarketing,…

  19. An Admissions Race that's Already Won

    ERIC Educational Resources Information Center

    Stevens, Mitchell L.

    2008-01-01

    The author recently spent a year and a half in the admissions office of a highly selective Eastern college as an ethnographer, seeking to understand just how admissions officers make their decisions. He accompanied them on recruitment trips to high schools and college fairs, helped manage their offices' relentless current of visitors and mail, and…

  20. College Admission Professionals: Who Are We Now?

    ERIC Educational Resources Information Center

    Rapelye, Janet Lavin

    1999-01-01

    Reflects on roles that admission professionals hold within the academic community. Explains that admission professionals are educators and business managers; bring in revenue; and serve as advisors to the president, as spokespeople to alumni/ae, and if fortunate, as counselors to students. Suggests that counselors focus on students because they…

  1. 49 CFR 25.300 - Admission.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Office of the Secretary of Transportation NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 25.300 Admission. (a) General. No person shall, on the basis of sex, be...

  2. 40 CFR 5.300 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex... of sex, be denied admission, or be subjected to discrimination in admission, by any recipient...

  3. 45 CFR 86.21 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex... of sex, be denied admission, or be subjected to discrimination in admission, by any recipient...

  4. 22 CFR 146.300 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Relations DEPARTMENT OF STATE CIVIL RIGHTS NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 146.300 Admission. (a) General. No person shall, on the basis of sex, be...

  5. 28 CFR 54.300 - Admission.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Administration DEPARTMENT OF JUSTICE (CONTINUED) NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 54.300 Admission. (a) General. No person shall, on the basis of sex, be...

  6. 43 CFR 41.300 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Lands: Interior Office of the Secretary of the Interior NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex... basis of sex, be denied admission, or be subjected to discrimination in admission, by any recipient...

  7. 45 CFR 86.21 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex... of sex, be denied admission, or be subjected to discrimination in admission, by any recipient...

  8. Admission to Law School: New Measures

    ERIC Educational Resources Information Center

    Shultz, Marjorie M.; Zedeck, Sheldon

    2012-01-01

    Standardized tests have been increasingly controversial over recent years in high-stakes admission decisions. Their role in operationalizing definitions of merit and qualification is especially contested, but in law schools this challenge has become particularly intense. Law schools have relied on the Law School Admission Test (LSAT) and an INDEX…

  9. Innovative Stemless Valve Eliminates Emissions

    NASA Technical Reports Server (NTRS)

    2008-01-01

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

  10. Potential flow in engine valves

    NASA Technical Reports Server (NTRS)

    Eck, Bruno

    1925-01-01

    The extensive applicability of the hydrodynamic theory to the problems of engine construction is clearly shown in the following attempt to determine by exact methods the nature of the flow in valves under variously restricted conditions. Observation shows that two principal kinds of flow occur in simple flat-seated valves. For small valve lifts, the flow is along the horizontal wall and is therefore deflected 90 degrees, but for greater valve lifts the flow separates and forms a free stream, whose angle of deflection naturally increases with increasing lift. Both these kinds of flow can, in fact, be theoretically explained

  11. Prosthetic valve endocarditis: an overview.

    PubMed

    Gnann, J W; Dismukes, W E

    1983-12-01

    Infection of an intracardiac prosthesis, the incidence of which is about 2.5% among patients having undergone valve replacement, is a serious complication with considerable morbidity and mortality. Early prosthetic valve endocarditis (PVE), with an onset within 60 days of valve replacement, accounts for approximately one-third of all cases, while the remaining two-thirds, occur more than two months postoperatively (late prosthetic valve endocarditis). Prosthetic valve endocarditis is most commonly caused by Staphylococcus epidermidis, less frequently by viridans streptococci, Staphylococcus aureus, and gram-negative bacilli. The most likely pathogenetic mechanisms in prosthetic valve endocarditis are intraoperative contamination and postoperative infections at extracardiac sites. Prominent clinical features include fever, new or changing heart murmurs, leukocytosis, anemia and hematuria. The etiologic microorganism can be isolated in more than 90% of all cases. Patients with proven prosthetic valve endocarditis should be examined daily to detect signs of congestive heart failure and changes in murmurs; electrocardiographic monitoring is essential for documentation of arrhythmias. With limitations, echocardiography, especially two-dimensional, may help to demonstrate vegetations or valvular dehiscence. Cinefluoroscopy may reveal loosening or dehiscence of the sewing ring or impaired motion of a radio-opaque poppet due to thrombus or vegetation. Cardiac catheterization, not always necessary even when surgical intervention is anticipated, may provide valuable information on the degree of dysfunction, multiple valve involvement, left ventricular function and extent of concomitant coronary artery disease. In patients with mechanical valves, prosthetic valve endocarditis may be associated with a high incidence of valve ring and myocardial abscesses; the reported frequency of valve ring abscesses is lower with porcine heterografts. Infections on mechanical valves

  12. Latest design of gate valves

    SciTech Connect

    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.

  13. Fluid mechanics of heart valves.

    PubMed

    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.

  14. Star GK Bileaflet Mechanical Valve Prosthesis-Patient Mismatch After Mitral Valve Replacement: A Chinese Multicenter Clinical Study

    PubMed Central

    Cao, Hua; Qiu, Zhihuang; Chen, Liangwan; Chen, Daozhong; Chen, Qiang

    2015-01-01

    Background The aim of this study was to investigate the incidence and immediate and mid-term effects of heart valve prosthesis-patient mismatch (PPM) after mitral valve replacement using the GK bileaflet mechanical valve. Material/Methods A total of 493 cases of mechanical mitral valve replacement were performed in the departments of cardiac surgery in 7 hospitals from January 2000 to January 2008. The patients included 142 men and 351 women ages 21 to 67 (average age, 48.75). The patients were followed for 3 years after surgery. The effective orifice area index (EOAI), ≤1.2 cm2/m2, was detected during the follow-up period and was defined as PPM. The patients were assigned to either the PPM group or the non-PPM group. Finally, the preoperative, perioperative and postoperative indexes of the 2 groups of patients were compared. Results A total of 157 patients had PPM 3 years after surgery. The incidence of PPM was 31.84%. Sixty-three patients in the PPM group received a 25-mm GK bileaflet valve (40.13%), 82 received a 27-mm valve (52.23%), and 12 (7.64%) received a 29-mm valve. There were significant differences in length of intensive care unit stay, duration of ventilator use, length of hospitalization, body surface area, EOAI, mean transmitral pressure gradient, and pulmonary artery pressure between the PPM and non-PPM group (P<0.05). There was a significant difference between preoperative and postoperative pulmonary artery pressures among non-PPM patients (P<0.05); however, there was no statistical difference in preoperative and postoperative pulmonary artery pressures among patients with PPM (P>0.05). Conclusions PPM after mitral valve replacement influences postoperative hemodynamics. Thus, larger-sized GK bileaflet mechanical valves are often used to reduce the risk of PPM. PMID:26313311

  15. Heart Valve Surgery Recovery and Follow Up

    MedlinePlus

    ... Venous Thromboembolism Aortic Aneurysm More Heart Valve Surgery Recovery and Follow Up Updated:Sep 14,2016 What to expect after heart valve surgery The normal recovery time after a heart valve surgery is usually ...

  16. 49 CFR 195.116 - Valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) Each valve must be both hydrostatically shell tested and hydrostatically seat tested without leakage to... the position of the valve (open, closed, etc.). (f) Each valve must be marked on the body or...

  17. The association between weather conditions and stroke admissions in Turkey

    NASA Astrophysics Data System (ADS)

    Çevik, Yunsur; Doğan, Nurettin Özgür; Daş, Murat; Ahmedali, Asliddin; Kul, Seval; Bayram, Hasan

    2015-07-01

    Although several factors such as cigarette smoking, blood pressure, diabetes, obesity, hypercholesterolemia, physical inactivity and dietary factors have been well documented to increase the risk for stroke, there are conflicting data about the role of meteorological variables in the etiology of stroke. We conducted a retrospective study to investigate the association between weather patterns, including daily temperature, humidity, wind speed, and air pressure, and stroke admissions to the Emergency Department of Atatürk Training and Research Hospital in Ankara, Turkey, between January 2009 and April 2010. Generalized additive models with logistic link function were used to investigate the relationship between predictors and days with and without stroke admission at lags 0-4. A total of 373 stroke patients were admitted to the emergency department (ED) between January 2009 and April 2010. Of patients, 297 had ischemic stroke (IS), 34 hemorrhagic stroke (HS), and 42 subarachnoidal hemorrhage (SAH). Although we did not find any association between overall admissions due to stroke and meteorological parameters, univariable analysis indicated that there were significantly more SAH cases on days with lower daily mean temperatures of 8.79 ± 8.75 °C as compared to relatively mild days with higher temperatures (mean temperature = 11.89 ± 7.94 °C, p = 0.021). The multivariable analysis demonstrated that admissions due to SAH increased on days with lower daily mean temperatures for the same day (lag 0; odds ratio (OR) [95 % confidence interval (95 % CI)] = 0.93 [0.89-0.98], p = 0.004) and lag 1 (OR [95 % CI] =0.76 [0.67-0.86], p = 0.001). Furthermore, the wind speed at both lag 1 (OR [95 % CI] = 1.63 [1.27-2.09], p = 0.001) and lag 3 (OR [95 % CI] = 1.43 [1.12-1.81], p = 0.004) increased admissions due to HS, respectively. In conclusion, our study demonstrated that there was an association between ED admissions due to SAH and HS and weather conditions suggesting that

  18. The association between weather conditions and stroke admissions in Turkey.

    PubMed

    Çevik, Yunsur; Doğan, Nurettin Özgür; Daş, Murat; Ahmedali, Asliddin; Kul, Seval; Bayram, Hasan

    2015-07-01

    Although several factors such as cigarette smoking, blood pressure, diabetes, obesity, hypercholesterolemia, physical inactivity and dietary factors have been well documented to increase the risk for stroke, there are conflicting data about the role of meteorological variables in the etiology of stroke. We conducted a retrospective study to investigate the association between weather patterns, including daily temperature, humidity, wind speed, and air pressure, and stroke admissions to the Emergency Department of Atatürk Training and Research Hospital in Ankara, Turkey, between January 2009 and April 2010. Generalized additive models with logistic link function were used to investigate the relationship between predictors and days with and without stroke admission at lags 0-4. A total of 373 stroke patients were admitted to the emergency department (ED) between January 2009 and April 2010. Of patients, 297 had ischemic stroke (IS), 34 hemorrhagic stroke (HS), and 42 subarachnoidal hemorrhage (SAH). Although we did not find any association between overall admissions due to stroke and meteorological parameters, univariable analysis indicated that there were significantly more SAH cases on days with lower daily mean temperatures of 8.79 ± 8.75 °C as compared to relatively mild days with higher temperatures (mean temperature = 11.89 ± 7.94 °C, p = 0.021). The multivariable analysis demonstrated that admissions due to SAH increased on days with lower daily mean temperatures for the same day (lag 0; odds ratio (OR) [95% confidence interval (95% CI)] = 0.93 [0.89-0.98], p = 0.004) and lag 1 (OR [95% CI] =0.76 [0.67-0.86], p = 0.001). Furthermore, the wind speed at both lag 1 (OR [95% CI] = 1.63 [1.27-2.09], p = 0.001) and lag 3 (OR [95% CI] = 1.43 [1.12-1.81], p = 0.004) increased admissions due to HS, respectively. In conclusion, our study demonstrated that there was an association between ED admissions due to SAH and HS

  19. Cost of vitamin K antagonist anticoagulant treatment in patients with metallic prosthetic valve in mitral position

    PubMed Central

    Ene, Gabriela; Garcia Raso, Aránzazu; Gonzalez-Dominguez Weber, Almudena; Hidalgo-Vega, Álvaro; Llamas, Pilar

    2016-01-01

    Background: The initiation of oral anticoagulation therapy after valve replacement surgery requires strict monitoring because these patients are at high risk for the development of thrombotic complications and present an increased risk of bleeding. Objectives: The aim of this study was to examine the total healthcare costs of oral anticoagulant treatment with vitamin K antagonists in patients with metallic prosthetic valves in the mitral position. Methods: Data from clinical records were used in the study including international normalized ratio results, number of medical visits, type of anticoagulant, use of rescue medication and hospital admissions from related complications. The drug cost was calculated based on the official Spanish Ministry of Health price list. Monitoring expenses were included in the cost of the medical supplies used in the procedures. Hospitalization costs were calculated using the diagnosis-related group price for each case. Results: We collected data from 151 patients receiving oral anticoagulation therapy with vitamin K antagonist who were diagnosed with mitral prosthesis (n = 90), mitro-aortic prosthesis (n = 57), and mitral and tricuspid prosthesis (n = 4). The total direct healthcare cost was €15302.59, with a mean total cost per patient per year of €1558.15 (±2774.58) consisting of 44.38 (±42.30) for drug cost, €71.41 (±21.43) for international normalized ratio monitoring, €429.52 (±126.87) for medical visits, €26.31 (±28.38) for rescue medication and €986.53 (±2735.68) for related complications. Conclusion: Most direct healthcare costs associated with the sampled patients arose from the specialist-care monitoring required for treatment. Good monitoring is inversely related to direct healthcare costs. PMID:27579168

  20. 241-AN-B valve pit manifold valves and position indication acceptance test procedure

    SciTech Connect

    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-B 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-B 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.

  1. 241-AN-A valve pit manifold valves and position indication acceptance test procedure

    SciTech Connect

    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.

  2. Curved butterfly bileaflet prosthetic cardiac valve

    DOEpatents

    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.

  3. Valve operating device for internal combustion engine

    SciTech Connect

    Yoshida, K.; Hirose, K.; Komatsu, T.; Shimoyama, K.; Tsuji, Y.

    1989-05-16

    A valve operating device is described for an internal combustion engine having cam followers disposed adjacent to each other for valve operation in mutually different modes by cams on a camshaft dependent on engine speed, and a selective coupling mechanism disposed between the cam followers and having at least one switching pin movable in a guide hole in a cam follower between a connecting position in which the cam followers, are interconnected and a disconnecting position in which the cam followers are disconnected. The improvement consists of an oil passage defined in at least one cam follower and passing through the guide hole, and the switching pin having means for controlling the rate of flow of oil through the oil passage and past the guide hole in response to movement of the switching pin between the connecting and disconnecting positions.

  4. Rotary selector valve

    SciTech Connect

    Jones, J.A.; Herndon, J.W.

    1991-02-05

    This paper discusses a multi-port valve which internally supports a rotatable trunnion having an elbow passage between a nozzle portion of the trunnion and a lower end outlet that communicates with a test port of the valve body. The outer end of the nozzle has an axially reciprocable hollow seal piston with a seal support ring whose outer face is formed with an endless groove to receive an O-ring. An actuating shaft is coaxially mounted in an upper end of the trunnion and has a lower end with an eccentric pin engaged in a slot of the seal piston to reciprocate the seal piston into and out of sealing registration around a port selected by rotation of the trunnion. External ends of the actuating shaft and trunnion are respectively drivably coupled to a coaxial sprocket wheel and geneva wheel. A housing on top of the valve contains an input rotor fitted with a cam and a drive roller for engaging radial slots of the geneva wheel alternately with cam engagement of the dwell notches of the geneva wheel. Concurrently and in advance of forward rotation of the geneva wheel, a rotor driven seal actuating yoke a free end engages one of a series of radial slots of the sprocket to rotate the sprocket in a retrograde direction to disengage the seal. When the yoke is disengaged, a detent mechanism temporarily locks the geneva and sprocket wheels together for co-rotation in a forward direction as the geneva drive roller again comes into engagement with the geneva wheel. After the nozzle has been advanced one step, further rotation of the input rotor advances an arm independently pivotally mounted on the yoke to compress a spring mechanism to bias the yoke and sprocket to compress the seal on a seat around the next port.

  5. Overhead-valve engine

    SciTech Connect

    Tamba, S.; Miyake, H.; Fukui, N.

    1987-05-05

    An overhead valve engine is described comprising: push rod receiving bores, at least one of the push rod receiving bores being maintained in communication at one end with a crank chamber and at an opposite end with a rocker arm chamber and at least one other push rod receiving bore being maintained in communication with the rocker arm chamber; push rods contained within push rod receiving bores; and a breather chamber in communication with at least one other push rod receiving bore in the vicinity of a camshaft.

  6. Valve morphology effect in aortic coarctation flow using realistic silicon models and magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Marrufo, Oscar; Solis-Najera, Sergio; Pibarot, Philippe; Kadem, Lyes; Kesharvarz-Motamed, Zahra; Rodriguez, Alfredo O.; Garcia, Julio

    2014-11-01

    Aortic valve morphology and phenotype may alter the aortic wall structure and its normal flow hemodynamics. However, the relationship between altered flow patterns and progression of wall pathology is often not fully understood in patients with aortic coartation and needs larger experimental work. In this study, we introduced a compatible experimental setup with magnetic resonance imaging (MRI) using a realistic aortic coarctation (AoCo) silicon model which can replicate physiological flow conditions (pressure, flow-wave, and systemic load). We evaluated the aortic valve hemodynamics of a normal tricuspid valve and a stenotic bicuspid valve using valve effective orifice area (EOA), peak and mean transvalvular pressure gradient (TPG). AoCo severity was assessed by the AoCo pressure gradient. For the tricuspid valve we obtained an EOA = 1.89 cm2, a peak TPG = 10 mmHg, and a mean TPG = 5 mmHg. For the bicuspid valve we obtained an EOA = 1.03 cm2, a peak TPG = 37 mmHg and a mean TPG = 13 mmHg. Furthermore, AoCo with tricuspid valve led to a peak AoCo pressure gradient (PG) = 11 mmHg and a mean PG = 5 mmHg. AoCo with bicuspid valve led to a peak PG = 6 mmHg and a mean PG = 3 mmHg. Aortic flow reattachment was more evident in presence of bicuspid valve and helical flow was present in all cases. This study showed that silicon prototyping in combination with MRI velocity measurements could successfully be used to assess hemodynamic effects of aortic valve morphology in aortic coarctation flow.

  7. Harken Caged-Disc Mitral Valve Replacement, 1969-1975: Analysis of Late Mortality, Thromboembolism, and Valve Failure

    PubMed Central

    Gray, Richard J.; Czer, Lawrence S.C.; Chaux, Aurelio; Sethna, Dhun; Derobertis, Michele; Raymond, Marjorie; Matloff, Jack M.

    1987-01-01

    We evaluated the long-term outcome of mitral valve replacement with a Harken caged-disc prosthesis for up to 11 years (range, 50 to 130 months; mean, 81 months) in 170 patients whose mean age was 55 years. The early (30-day) mortality was 11.2% (19 out of 170 patients). Late follow-up information was obtained for 144 (95%) of the 151 survivors. The actuarial survival was 57% at 5 years and 40% at 10 years. Overall mortality was associated with advanced age, male sex, an ischemic origin for the mitral valve disease, and nonuse of warfarin anticoagulation. Late deaths (n=59) were valve-related in 46%, cardiac but non-valve-related in 44%, and noncardiac in 10% of the cases. One thromboembolic event or more occurred in 41 patients (incidence, 5.7% per patient year), 14 of whom died (24% of the late deaths). All four patients who were not on warfarin, aspirin, or other antithrombotic therapy experienced thromboemboli. This complication was correlated with the nonuse of warfarin-type anticoagulation, with mitral regurgitation, and with late cardiac death. Mechanical prosthetic failure resulted in reoperation or death in 7.6% of the late survivors (1.5% per patient year). In 75 patients with normally functioning prostheses, the disc-to-sewing ring ratio was established by means of cinefluoroscopy (0.93 ± 0.04, mean ± 25D). Because of the high proportion of cardiac valve-related deaths (46%), the high incidence of late mortality due to thromboembolic events (24%), and the 7.6% incidence of reoperation or death resulting from mechanical valve failure, close follow-up with cinefluoroscopy and continued warfarin anticoagulation (alone or in combination with dipyridamole) are essential after mitral valve replacement with the Harken caged-disc prosthesis. (Texas Heart Institute Journal 1987; 14:411-417) Images PMID:15227298

  8. [The assessment of mechanical heart valves stenosis in adults after aortic valve replacement: the advantage of full-flow design of mechanical valve].

    PubMed

    Bokeria, L A; Bokeria, O L; Fadeev, A A; Makhachev, O A; Kosareva, T I; Averina, I I

    2013-01-01

    The analysis of transprosthetic hemodynamics in adults after aortic valve replacement in the Bakoulev Center for Cardiovascular Surgery in 2007-2010 demonstrated the hemodynamic advantage of the concept of new full-flow mechanical aortic valve prosthesis "CorBeat". Having the same size of internal orifice and tissue annulus diameters, the values of transprosthetic parameters (peak and mean gradients, blood flow velocities) through "CorBeat" were close to physiological values of transvalvular native aortic parameters and had a tendency to be not dependent on the size of prosthesis (p = 0.63). In the article for the first time a morphometric database of geometric values of internal orifice area of normal native aortic valves in adults was used taking into account both the gender and the body surface area's of a patient. There was also used the standardized prosthesis size Z-score which represents the number of SDs by which the internal prosthesis area differs from the mean normal native aortic valve area for the patient's body surface area. The article emphasizes the need of the personal selection of the size and the type of prosthesis for any patient as well as the need for new design development of prosthetic heart valves.

  9. Mitral valve surgery - minimally invasive

    MedlinePlus

    ... Saunders; 2012:chap 61. Otto CM, Bonow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Mitral Valve Prolapse Browse the Encyclopedia A.D. ...

  10. Valve designed with elastic seat

    NASA Technical Reports Server (NTRS)

    Mac Glashan, W. F., Jr.

    1965-01-01

    Absolute valve closure is accomplished by a machined valve with an axially annular channel which changes the outlet passage into a thin tubular elastic seat member with a retainer backup ring. The elasticity of the seat provides tight conformity to ball irregularity.

  11. Variable gas leak rate valve

    DOEpatents

    Eernisse, Errol P.; Peterson, Gary D.

    1976-01-01

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

  12. Air flow through poppet valves

    NASA Technical Reports Server (NTRS)

    Lewis, G W; Nutting, E M

    1920-01-01

    Report discusses the comparative continuous flow characteristics of single and double poppet valves. The experimental data presented affords a direct comparison of valves, single and in pairs of different sizes, tested in a cylinder designed in accordance with current practice in aviation engines.

  13. Surge-damping vacuum valve

    DOEpatents

    Bullock, Jack C.; Kelly, Benjamin E.

    1980-01-01

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

  14. FLUID PURIFIER AND SEALING VALVE

    DOEpatents

    Swanton, W.F.

    1962-04-24

    An improved cold trap designed to condense vapors and collect foreign particles in a flowing fluid is described. In the arrangement, a valve is provided to prevent flow reversal in case of pump failure and to act as a sealing valve. Provision is made for reducing the temperature of the fluid being processed, including a pre-cooling stage. (AEC)

  15. Late outcome of patients with Braunwald-Cutter mitral valve replacement.

    PubMed

    Abdulali, S A; Silverton, N P; Schoen, F J; Saunders, N R; Ionescu, M I

    1984-12-01

    Eighty patients who underwent mitral valve replacement (MVR) with Braunwald-Cutter prostheses (54, single valve replacement; 26, multiple valve replacement) between December, 1972, and September, 1975, are discussed. The period of follow-up ranged from 72 to 120 months with a mean of 84.6 months. For the hospital survivors, actuarial survival at ten years was 73 +/- 6.7% for patients with MVR alone and 30 +/- 17.5% for those with multiple valve replacement. The linearized rate of embolic complications in patients with MVR was 3.2% per year and in patients with multiple valve replacement, 1.5% per year. These low rates of embolism allow a favorable comparison of the Braunwald-Cutter valve with other mechanical prostheses. There was no evidence of serious poppet wear or poppet escape after ten years of the valve in the mitral and tricuspid positions. Thus, elective replacement of the Braunwald-Cutter valve from the atrioventricular position because of this potential problem is not considered necessary. In the aortic position, escape of the poppet from the valve has occurred as late as 101 months. The overall morbidity for the group was high. Only 34% of the patients having MVR and 12% of those with multiple valve replacement are expected to be alive and to remain free from any major complication ten years after operation.

  16. Heimlich valve for chest drainage.

    PubMed

    Heimlich, H J

    1983-01-01

    The Heimlich chest drainage valve was developed so that the process of draining the pleural cavity could be accomplished in a safe, relatively simple, and efficient manner. Replacing the cumbersome underwater drainage bottle system, the Heimlich valve connects to chest tubing and allows fluid and air to pass in one direction only. The valve, which functions in any position, need never be clamped, and regulated suction can be attached to it if necessary. The valve drains into a plastic bag that can be held at any level, allowing the patient undergoing chest drainage to be ambulatory simply by carrying the bag. The construction and function of the valve is easily understood by medical and nursing staffs. It is presterilized, stored in a sterile package, and readily utilized on emergency vehicles and in the operating room.

  17. Electro-Mechanical Coaxial Valve

    NASA Technical Reports Server (NTRS)

    Patterson, Paul R (Inventor)

    2004-01-01

    Coaxial valves usually contain only one moving part. It has not been easy, then, to provide for electric motor actuation. Many actuators being proposed involve designs which lead to bulky packages. The key facing those improving coaxial valves is the provision of suitable linear actuation. The valve herein indudes a valve housing with a flow channel there-through. Arranged in the flow channel is a closing body. In alignment with the closing body is a ball screw actuator which includes a ball nut and a cylindrical screw. The ball nut sounds a threaded portion of the cylindrical screw. The cylindrical screw is provided with a passageway there-through through which fluid flows. The cylindrical screw is disposed in the flow channel to become a control tube adapted to move toward and away from the valve seat. To rotate the ball nut an actuating drive is employed driven by a stepper motor.

  18. Titanium aluminide automotive engine valves

    SciTech Connect

    Hartfield-Wuensch, S.E.; Sperling, A.A.; Morrison, R.S.; Dowling, W.E. Jr.; Allison, J.E.

    1995-12-31

    The low density and high elevated temperature strength make titanium aluminide alloys an excellent candidate for automotive exhaust valve applications. Lighter weight valve train components allow either improved performance or reduction of valve spring loads which reduce noise and friction, thereby improving fuel economy. The key to successful application of TiAl alloys for automotive engine valves is not optimization of strength and ductility, but rather the development of a low-cost, high-volume manufacturing method. Different manufacturing approaches will be discussed in this paper, along with their advantages and disadvantages. Currently, casting appears to be the lowest-cost alternative that produces adequate material properties and emphasis is being placed on this manufacturing approach. The results of several successful engine tests will also be discussed, including results on a binary TiAl alloy. However, these engine tests have indicated that TiAl alloy valves will require tip protection and stem coating.

  19. A Parylene MEMS Electrothermal Valve

    PubMed Central

    Li, Po-Ying; Givrad, Tina K.; Holschneider, Daniel P.; Maarek, Jean-Michel I.; Meng, Ellis

    2011-01-01

    The first microelectromechanical-system normally closed electrothermal valve constructed using Parylene C is described, which enables both low power (in milliwatts) and rapid operation (in milliseconds). This low-power valve is well suited for applications in wirelessly controlled implantable drug-delivery systems. The simple design was analyzed using both theory and modeling and then characterized in benchtop experiments. Operation in air (constant current) and water (current ramping) was demonstrated. Valve-opening powers of 22 mW in air and 33 mW in water were obtained. Following integration of the valve with catheters, our valve was applied in a wirelessly operated microbolus infusion pump, and the in vivo functionality for the appropriateness of use of this pump for future brain mapping applications in small animals was demonstrated. PMID:21350679

  20. Atmospheric dump valve engineering analysis

    SciTech Connect

    Mendoza, B.; McNemar, P.

    1990-01-01

    This report documents the activities undertaken after the atmospheric dump valves (ADVs) failed to operate following a Unit 3 reactor trip. The activities consisted of testing valves in all three units, examining Palo Verde Nuclear Generating Station (PVNGS) history with the valves, determining causes for failures, and making recommendations. The PVNGS engineering departments performed an in-depth review of the history, operation, maintenance, and design of ADVs. A preliminary mathematical model of the valves' dynamic behavior was developed by Arizona State University. The corrective actions are designed to eliminate the anomalies noted with the Unit 1 and 3 ADVs. Subsequent monitoring and testing activities following the planned modifications will ensure the ADVs remain operable during modes required by the PVNGS technical specifications. Through this increased monitoring and testing program, the valve modifications will be evaluated to confirm that the required level of reliability has been reached for the ADVs. The specific failures have been evaluated and the causes determined.

  1. Electromagnetic unit fuel injector with piston assist solenoid actuated control valve

    SciTech Connect

    Teerman, R. F.; Bosch, R. H.; Wirth, R. C.

    1985-11-05

    An electromagnetic unit fuel injector includes a pump assembly having an external actuated plunger reciprocable in a bushing with flow therefrom during a pump stroke being directed to a fuel injection nozzle of the assembly. Fuel flow from the pump can also flow through a passage means, containing a normally open, substantially pressure-balanced control valve actuated by a solenoid assembly in the valve closing direction to block drain flow during a pump stroke, as desired. A piston, actuated by discharge fuel pressure is operatively connected to the control valve to assist the solenoid in holding the control valve in a closed position.

  2. Lunar phases and psychiatric hospital admissions.

    PubMed

    Gorvin, J J; Roberts, M S

    1994-12-01

    To assess the lunar hypothesis as predictive of mental health emergencies and antisocial behavior, the relation of the lunar hypothesis and the occurrence of psychiatric hospital admissions of developmentally disabled adults was examined. The full moon phase of the lunar cycle did not explain a higher rate of hospital admission and accounted for only .007% of the variance. A critique of the methodology in prior research led to the suggestion that more immediate stressors and environmental factors are more plausible contributing factors to hospital admission.

  3. Dynamic Spin Valve

    NASA Astrophysics Data System (ADS)

    Demirtas, Sezen; Koymen, Ali; Salamon, Myron

    2010-03-01

    In this study we investigate a dynamic extension of well known classic spin valves. Ultra thin films were dc sputtered in a UHV chamber and their dynamic responses were measured by ferromagnetic resonance (FMR). Two Co layers, separated by a nonmagnetic Ag layer--thick enough to suppress exchange coupling--were deposited, with one of them coupled to a Gd underlayer, forming a Co(1)/Ag/Co(2)/Gd multilayer. At room temperature both Co(1) and Co(2) FMR's are observed for the external magnetic field in the plane of the film. The field for resonance of Co(2) is reduced significantly relative to Co(1), with the paramagnetic moment of the Gd apparently added to the Co magnetization, and the linewidth is broader. Spin pumping effects are minimal since Co(1) and Co(2) do not resonate at the same field.. The Co(2) FMR disappears at the TC of Gd leaving the linewidth of the Co(1) FMR weakly temperature dependent down to the compensation temperature of the Co(2)/Gd bilayer. Below that point, the two Co layers in this dynamic spin valve device are in antiparallel alignment, leading to strong broadening of the Co(1) FMR with decreasing temperature.

  4. Mitral Valve Annuloplasty

    PubMed Central

    Rausch, Manuel K.; Bothe, Wolfgang; Kvitting, John-Peder Escobar; Swanson, Julia C.; Miller, D. Craig; Kuhl, Ellen

    2012-01-01

    Mitral valve annuloplasty is a common surgical technique used in the repair of a leaking valve by implanting an annuloplasty device. To enhance repair durability, these devices are designed to increase leaflet coaptation, while preserving the native annular shape and motion; however, the precise impact of device implantation on annular deformation, strain, and curvature is unknown. Here we quantify how three frequently used devices significantly impair native annular dynamics. In controlled in vivo experiments, we surgically implanted eleven flexible-incomplete, eleven semi-rigid-complete, and twelve rigid-complete devices around the mitral annuli of 34 sheep, each tagged with 16 equally-spaced tantalum markers. We recorded four-dimensional marker coordinates using biplane videofluoroscopy, first with device and then without, which were used to create mathematical models using piecewise cubic splines. Clinical metrics (characteristic anatomical distances) revealed significant global reduction in annular dynamics upon device implantation. Mechanical metrics (strain and curvature fields) explained this reduction via a local loss of anterior dilation and posterior contraction. Overall, all three devices unfavorably reduced annular dynamics. The flexible-incomplete device, however, preserved native annular dynamics to a larger extent than the complete devices. Heterogeneous strain and curvature profiles suggest the need for heterogeneous support, which may spawn more rational design of annuloplasty devices using design concepts of functionally graded materials. PMID:22037916

  5. The effect of the aortic valve orientation on cavitation.

    PubMed

    Johansen, Peter; Travis, Brandon R; Smerup, Morten; Decker Christensen, Thomas; Funder, Jonas; Nyboe, Camilla; Nygaard, Hans; Hasenkam, J Michael

    2016-08-01

    When implanting a mechanical aortic valve the annulus orientation is important with respect to turbulence. However, the effect on cavitation has not yet been investigated. The aim of this study was to investigate how cavitation is influenced hereof in vivo. Three pigs were included in the study. An Omnicarbon 21mm valve equipped with a rotating mechanism enabling controlled rotation of the valve was implanted in aortic position. Under stable hemodynamic conditions, measurements were performed using a hydrophone positioned at the aortic root. The valve was rotated from 0-360° in increments of 30°. From the pressure fluctuations recorded by the hydrophone the root mean square of the 50 kHz high pass filtered signal as well as the non-deterministic signal energy was calculated as indirect measures of cavitation. Various degrees of cavitation were measured but no relationship was found between either of the two cavitation measures and the valve orientation. Hemodynamics varied during the experiments for all pigs (3.9-5.7 l/min; 5.0-7.2 l/min; 3.1-7.5 l/min). Changes in cavitation quantities seemed to be caused by changes in hemodynamics rather than valve angular position. In conclusion, these results do not favor any position over another in terms of cavitation potential.

  6. Mechanism utilizing a single rocker arm for controlling an internal combustion engine valve

    SciTech Connect

    Burandt, C.O.

    1988-02-09

    This patent describes in combination with an internal combustion engine having a rotatable camshaft, a cam on the camshaft, a combustion chamber and a reciprocable valve member for opening and closing a valve port in communication with the combustion chamber, a mechanism for operating the valve member comprising a rocker arm having first and second angularly disposed and integrally connected legs. The first leg having a cam follower suface thereon having a first section thereof extending in the same general direction that the valve member reciprocates and having a second section thereof curving toward the valve member and toward the direction in which the valve member reciprocates, means mounting the rocker arm for rocking movement about a first axis, and means for shifting the first axis relative to the camshaft in also the same general direction the valve member reciprocates so that various portions of the first and second sections of the cam follower surface on the first leg are relatively engageable with the cam, sufficient shifting of the first axis in the same general direction producing a desmodromic action, and the second leg including a single portion thereof engaging the valve member so that only the single portion acts on the valve member.

  7. 46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any... pressure or vacuum in enclosed places....

  8. 46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any... pressure or vacuum in enclosed places....

  9. 46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any... pressure or vacuum in enclosed places....

  10. 46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any... pressure or vacuum in enclosed places....

  11. 46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any... pressure or vacuum in enclosed places....

  12. Jet-controlled freeze valve for use in a glass melter

    DOEpatents

    Routt, Kenneth R.

    1986-09-02

    A drain valve for use in a furnace for the melting of thermoplastic material. The furnace includes a drain cavity formed in its bottom for withdrawing a flow of thermoplastic material. The drain valve includes a flow member which include a flow tube having an inlet and outlet for the material, and coaxially disposed concentric tubular members defining annuli surrounding the flow tube. The tubular members include heating and cooling means for the flow tube. The flow member is adapted to fit in mating relationship in the drain cavity. A freeze valve member is disposed adjacent the outlet of the flow member. The freeze valve member includes heating means and has a plurality of air jets adapted to direct streams of pressurized air at the outlet to control the flow of thermoplastic material through the flow members. The drain valve can also be used in a furnace of glass melting that includes a drain cavity for withdrawing molten glass from the furnace. The drain valve includes a flow tube member having an inlet and outlet, and having heating and cooling means. The tube member is adapted to fit in mating relationship with the drain cavity. A freeze valve member is disposed at the outlet of the flow tube member. The freeze valve member includes heating means and has a plurality of air jets adapted to direct a stream of pressurized air at the outlet to control the flow of glass through the flow tube member.

  13. Jet-controlled freeze valve for use in a glass melter

    DOEpatents

    Routt, Kenneth R.

    1986-01-01

    A drain valve for use in a furnace for the melting of thermoplastic material. The furnace includes a drain cavity formed in its bottom for withdrawing a flow of thermoplastic material. The drain valve includes a flow member which include a flow tube having an inlet and outlet for the material, and coaxially disposed concentric tubular members defining annuli surrounding the flow tube. The tubular members include heating and cooling means for the flow tube. The flow member is adapted to fit in mating relationship in the drain cavity. A freeze valve member is disposed adjacent the outlet of the flow member. The freeze valve member includes heating means and has a plurality of air jets adapted to direct streams of pressurized air at the outlet to control the flow of thermoplastic material through the flow members. The drain valve can also be used in a furnace of glass melting that includes a drain cavity for withdrawing molten glass from the furnace. The drain valve includes a flow tube member having an inlet and outlet, and having heating and cooling means. The tube member is adapted to fit in mating relationship with the drain cavity. A freeze valve member is disposed at the outlet of the flow tube member. The freeze valve member includes heating means and has a plurality of air jets adapted to direct a stream of pressurized air at the outlet to control the flow of glass through the flow tube member.

  14. Internal Acoustics of a Pintle Valve with Supercritical Helium Flow

    NASA Technical Reports Server (NTRS)

    Fishbach, Sean R.; Davis, R. Benjamin

    2010-01-01

    Large amplitude flow unsteadiness is a common phenomenon within the high flow rate ducts and valves associated with propulsion systems. Boundary layer noise, shear layers and vortex shedding are a few of the many sources of flow oscillations. The presence of lightly damped acoustic modes can organize and amplify these sources of flow perturbation, causing undesirable loading of internal parts. The present study investigates the self-induced acoustic environment within a pintle valve subject to high Reynolds Number flow of helium gas. Experiments were conducted to measure the internal pressure oscillations of the Ares I Launch Abort System (LAS) Attitude Control Motor (ACM) valve. The AGM consists of a solid propellant gas generator with eight pintle valves attached to the aft end. The pintle valve is designed to deliver variable upstream conditions to an attache( converging diverging nozzle. In order to investigate the full range of operating conditions 28 separate tests were conducted with varying pintle position and upstream pressure. Helium gas was utilized in order to closely mimic the speed of sound of the gas generator exhaust, minimizing required scaling during data analysis. The recordec pressure measurements were interrogated to multiple ends. The development of root mean square (RMS) value! versus Reynolds Number and Pintle position are important to creating bounding unsteady load curves for valve internal parts. Spectral analysis was also performed, helping to identify power spectral densities (PSD) of acoustic natural frequencies and boundary layer noise. An interesting and unexpected result was the identification of an acoustic mode within the valve which does not respond until the valve was over 60% open. Further, the response amplitude around this mode can be as large or larger than those associated with lower frequency modes.

  15. Diagnosis and treatment of early bioprosthetic malfunction in the mitral valve position due to thrombus formation.

    PubMed

    Butnaru, Adi; Shaheen, Joseph; Tzivoni, Dan; Tauber, Rachel; Bitran, Daniel; Silberman, Shuli

    2013-11-01

    Bioprosthetic valve thrombosis is uncommon and the diagnosis is often elusive and may be confused with valve degeneration. We report our experience with mitral bioprosthetic valve thrombosis and suggest a therapeutic approach. From 2002 to 2011, 149 consecutive patients who underwent mitral valve replacement with a bioprosthesis at a single center were retrospectively screened for clinical or echocardiographic evidence of valve malfunction. Nine were found to have valve thrombus. All 9 patients had their native valve preserved, representing 24% of those with preserved native valves. Five patients (group 1) presented with symptoms of congestive heart failure at 16.4 ± 12.4 months after surgery. Echocardiogram revealed homogenous echo-dense film on the ventricular surface of the bioprosthesis with elevated transvalvular gradient, resembling early degeneration. The first 2 patients underwent reoperation: valve thrombus was found and confirmed by histologic examination. Based on these, the subsequent 3 patients received anticoagulation treatment with complete thrombus resolution: mean mitral gradient decreased from 23 ± 4 to 6 ± 1 mm Hg and tricuspid regurgitation gradient decreased from 83 ± 20 to 49 ± 5 mm Hg. Four patients (group 2) were asymptomatic, but routine echocardiogram showed a discrete mass on the ventricular aspect of the valve: 1 underwent reoperation to replace the valve and 3 received anticoagulation with complete resolution of the echocardiographic findings. In conclusion, bioprosthetic mitral thrombosis occurs in about 6% of cases. In our experience, onset is early, before anticipated valve degeneration. Clinical awareness followed by an initial trial with anticoagulation is warranted. Surgery should be reserved for those who are not responsive or patients in whom the hemodynamic status does not allow delay. Nonresection of the native valve at the initial operation may play a role in the origin of this entity.

  16. A multidisciplinary team case management approach reduces the burden of frequent asthma admissions.

    PubMed

    Burke, Hannah; Davis, Jenny; Evans, Sian; Flower, Laura; Tan, Andrew; Kurukulaaratchy, Ramesh J

    2016-07-01

    Up to 10% of asthmatics have "difficult asthma"; however, they account for 80% of asthma-related expenditure and run the highest risk of acute severe exacerbations. An estimated 75% of admissions for asthma are avoidable. Guidelines advise that these patients be managed by an experienced specialist multidisciplinary team (MDT). We aimed to assess the impact of a case management strategy delivered via specialist MDTs on acute healthcare utilisation of patients with frequent asthma admissions. An MDT (consultant, specialist nurse, physiotherapist and psychologist) case management strategy was introduced in 2010 at University Hospital Southampton Foundation Trust (Southampton, UK) to support patients with frequent asthma admissions during admission and then in clinic. To assess efficacy, we systematically searched the hospital database for patients acutely admitted for asthma on two or more occasions in 2010, 2011 and 2012. Data were collected retrospectively covering patient demographics, admission details, asthma severity and comorbidity. From 2010 to 2012, 84 patients were admitted on two or more occasions per year (80% female, mean body mass index 31 kg·m(-2) and 55% psychological comorbidity). After introducing an MDT approach repeat asthma admissions fell by 33% from 127 in 2010 to 84 in 2012 (p=0.0004). In addition, bed days fell by 52% from 895 in 2010 to 430 in 2010 (p=0.015). An MDT case management approach significantly reduces hospitalisation in difficult asthma patients with prior frequent admission.

  17. A multidisciplinary team case management approach reduces the burden of frequent asthma admissions

    PubMed Central

    Burke, Hannah; Davis, Jenny; Evans, Sian; Flower, Laura; Tan, Andrew

    2016-01-01

    Up to 10% of asthmatics have “difficult asthma”; however, they account for 80% of asthma-related expenditure and run the highest risk of acute severe exacerbations. An estimated 75% of admissions for asthma are avoidable. Guidelines advise that these patients be managed by an experienced specialist multidisciplinary team (MDT). We aimed to assess the impact of a case management strategy delivered via specialist MDTs on acute healthcare utilisation of patients with frequent asthma admissions. An MDT (consultant, specialist nurse, physiotherapist and psychologist) case management strategy was introduced in 2010 at University Hospital Southampton Foundation Trust (Southampton, UK) to support patients with frequent asthma admissions during admission and then in clinic. To assess efficacy, we systematically searched the hospital database for patients acutely admitted for asthma on two or more occasions in 2010, 2011 and 2012. Data were collected retrospectively covering patient demographics, admission details, asthma severity and comorbidity. From 2010 to 2012, 84 patients were admitted on two or more occasions per year (80% female, mean body mass index 31 kg·m−2 and 55% psychological comorbidity). After introducing an MDT approach repeat asthma admissions fell by 33% from 127 in 2010 to 84 in 2012 (p=0.0004). In addition, bed days fell by 52% from 895 in 2010 to 430 in 2010 (p=0.015). An MDT case management approach significantly reduces hospitalisation in difficult asthma patients with prior frequent admission. PMID:27730207

  18. Self-Rupturing Hermetic Valve

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  19. Repeat mitral valve replacement: 30-years' experience.

    PubMed

    Expósito, Víctor; García-Camarero, Tamara; Bernal, José M; Arnáiz, Elena; Sarralde, Aurelio; García, Iván; Berrazueta, José R; Revuelta, José M

    2009-08-01

    Prosthetic heart valve dysfunction is an acquired condition that carries a significant risk of emergency surgery. However, the long-term natural history of the condition is not well understood. Between 1974 and 2006, 1535 isolated mitral valve replacements were performed at our hospital (in-hospital mortality 5%). In total, 369 patients needed a second operation (in-hospital mortality 8.1%), while 80 (age 59.8+/-11.4 years) needed a third. The reasons for the third intervention were structural deterioration (67.5%), paravalvular leak (20%) and endocarditis (6.3%). Some 15 patients died in hospital (18.8%). After a mean follow-up period of 17.8 years, 21 patients needed another intervention (i.e., a fourth intervention). The actuarial reoperation-free rate at 20 years was 40.1+/-13.8%. The late mortality rate was 58.5% (18-year survival rate 15.4+/-5.4%). Indications for repeat mitral valve replacement must be judged on an individual basis given the high risk associated with surgery.

  20. 43 CFR 4.1141 - Admissions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... directed serves on the requesting party— (1) A sworn statement denying specifically the relevant matters of which an admission is requested; (2) A sworn statement setting forth in detail the reasons why he...

  1. 43 CFR 4.1141 - Admissions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... directed serves on the requesting party— (1) A sworn statement denying specifically the relevant matters of which an admission is requested; (2) A sworn statement setting forth in detail the reasons why he...

  2. 43 CFR 4.1141 - Admissions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... directed serves on the requesting party— (1) A sworn statement denying specifically the relevant matters of which an admission is requested; (2) A sworn statement setting forth in detail the reasons why he...

  3. Marketing in Admissions: The Information System Approach.

    ERIC Educational Resources Information Center

    Wofford, O. Douglas; Timmerman, Ed

    1982-01-01

    A marketing information system approach for college admissions is outlined that includes objectives, information needs and sources, a data collection format, and information evaluation. Coordination with other institutional information systems is recommended. (MSE)

  4. The Parent Role in College Admission.

    ERIC Educational Resources Information Center

    Krugman, Mary K.

    1990-01-01

    Discusses techniques secondary school counselors can use to help parents understand and negotiate the college admissions process, including encouraging parental self-assessment; assisting parents to assess student; giving parents special tips; and maintaining open and ethical communication. (ABL)

  5. 28 CFR 549.42 - Involuntary admission.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... SERVICES Administrative Safeguards for Psychiatric Treatment and Medication § 549.42 Involuntary admission. A court determination is necessary for involuntary hospitalization for psychiatric treatment. A sentenced inmate, not currently committed for psychiatric treatment, who is not able or willing...

  6. [A rare case of two mechanisms of prosthetic valve dysfunction in the same patient].

    PubMed

    Cardoso, Gonçalo; Trabulo, Marisa; Andrade, Maria João; Ribeiras, Regina; Rodrigues, Rui; Neves, José Pedro; Queiróz e Melo, João; Mendes, Miguel

    2013-12-01

    Prosthetic valve dysfunction is a significant clinical event. Determining its etiological mechanism and severity can be difficult. The authors present the case of a 50-year-old man, with two mechanical valve prostheses in aortic and mitral positions, hospitalized for decompensated heart failure. He had a long history of rheumatic multivalvular disease and had undergone three heart surgeries. On admission, investigation led to a diagnosis of severe dysfunction of both mechanical prostheses with different etiologies and mechanisms: pannus formation in the prosthetic aortic valve and intermittent dysfunction of the mitral prosthesis due to interference of a ruptured chorda tendinea in closure of the disks. The patient was reoperated, leading to significant improvement in functional class.

  7. Transcatheter valve-in-valve implantation for failed mitral prosthesis: the first experience in Japan.

    PubMed

    Tada, Norio; Enta, Yusuke; Sakurai, Mie; Ootomo, Tatsushi; Hata, Masaki

    2017-01-01

    An 82-year-old woman had a history of mitral valve replacement with a 25-mm MOSAIC (Medtronic, USA) for severe mitral regurgitation (MR) 8 years previously. Recently, she developed heart failure due to MR secondary to prosthetic valve failure. She underwent transcatheter valve-in-valve implantation with a 23-mm SAPIEN XT (Edwards Lifesciences, USA) to the prosthetic mitral valve by transapical approach. To our knowledge, this is the first reported case of transcatheter valve implantation for failed mitral prosthetic valve using valve-in-valve technique in Japan.

  8. Device for varying engine valve timing

    SciTech Connect

    Hampton, K.

    1988-07-05

    A device is described for angularly displacing a camshaft relative to the crankshaft of an IC engine to vary the engine valve timing, comprising; a hub member; means to attach the hub member to the engine crankshaft; a drive member rotatably mounted on the hub member, and means connecting the drive member in driving relationship with the engine crankshaft; an advancing member; a first means interconnecting the advancing member with the hub member affecting limited axial movement of the advancing member relative to the hub member; a second means interconnecting the advancing member with the drive member which upon axial movement of the advancing member causes limited rotation of the drive member relative to the hub member; an annular means mounted on the hub member, the advancing member mounted on the annular means; coacting meshing means formed in part on the annular means for moving the advancing member axially relative to the hub upon limited rotation of the annular means relative to the hub; and a non-rotational retarder means which when actuated applies a retarding torque to the annular means causing limited rotation of the annular means relative to the hub and thus cause the advancing member to move axially of the hub whereby the drive member is moved a limited angular distance relative to the hub member.

  9. Minimally invasive aortic valve surgery

    PubMed Central

    Castrovinci, Sebastiano; Emmanuel, Sam; Moscarelli, Marco; Murana, Giacomo; Caccamo, Giuseppa; Bertolino, Emanuela Clara; Nasso, Giuseppe; Speziale, Giuseppe; Fattouch, Khalil

    2016-01-01

    Aortic valve disease is a prevalent disorder that affects approximately 2% of the general adult population. Surgical aortic valve replacement is the gold standard treatment for symptomatic patients. This treatment has demonstrably proven to be both safe and effective. Over the last few decades, in an attempt to reduce surgical trauma, different minimally invasive approaches for aortic valve replacement have been developed and are now being increasingly utilized. A narrative review of the literature was carried out to describe the surgical techniques for minimally invasive aortic valve surgery and report the results from different experienced centers. Minimally invasive aortic valve replacement is associated with low perioperative morbidity, mortality and a low conversion rate to full sternotomy. Long-term survival appears to be at least comparable to that reported for conventional full sternotomy. Minimally invasive aortic valve surgery, either with a partial upper sternotomy or a right anterior minithoracotomy provides early- and long-term benefits. Given these benefits, it may be considered the standard of care for isolated aortic valve disease. PMID:27582764

  10. Cavitation guide for control valves

    SciTech Connect

    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.

  11. Operating mechanism for dual valves in an internal combustion engine

    SciTech Connect

    Nagahiro, K.; Ishida, A.; Kajiwara, S.

    1987-04-14

    A valve operating mechanism is described for an internal combustion engine having a camshaft, a pair of intake or exhaust valves for each engine cylinder and a rocker shaft, comprising: first and second rocker arms pivotally mounted on the rocker shaft in adjacent relationship and engaging the pair of valves. The first rocker arm engages the camshaft; and piston means in the rocker arms selectively shiftable between positions connecting the rocker arms for pivotal movement in unison and disconnecting the rocker arms for independent movement. The piston means includes two pistons slidably mounted in the first rocker arm with one piston slidable into the second rocker arm for connecting the first and second rocker arms.

  12. Lock Culvert Valves; Hydraulic Design Considerations

    DTIC Science & Technology

    2011-06-01

    lock culvert valves with particular emphasis on reverse tainter valves. Hydraulic coefficients, used to quantify energy losses at valves and the jet...due to a sudden culvert expansion did increase the energy losses in the flow as the jet was dissipated. This additional head loss and associated...8 Figure 5. Loss coefficient for vertical-lift valve having a 45 degree lip

  13. Immigration, moving house and psychiatric admissions.

    PubMed

    Johansson, L M; Sundquist, J; Johansson, S E; Bergman, B

    1998-08-01

    This study was designed to elucidate psychiatric admission rates for native Swedes and foreign-born individuals during the period 1991-1994, when Sweden had a great influx of refugees. During the same period, and even earlier, psychiatric in-patient care had been reduced. Tests of differences between Swedes and foreign-born individuals in first psychiatric admission rates were performed using Poisson regressions, and the risk of a readmission was assessed using a proportional hazard model. Foreign-born individuals and native Swedes, both males and females, showed a similar admission pattern with regard to the number of admissions. Foreign-born males under 55 years of age and foreign-born females under 35 years of age had significantly higher admission rates than native Swedes. In total, native Swedes, both males and females, were hospitalized for a significantly longer period than the foreign-born subjects. About 43% of the patients were readmitted. The risk of a readmission was significantly increased among those with a high rate of internal migration. The high admission rates for young foreign-born individuals might be explained by a high incidence of mental illness owing to the trauma of being violently forced to migrate, acculturation difficulties, or unsatisfactory social circumstances such as high unemployment. The shorter hospitalization time could be due to undertreatment or less serious mental illness.

  14. Stemless ball valve

    NASA Technical Reports Server (NTRS)

    Burgess, Kevin (Inventor); Yakos, David (Inventor); Walthall, Bryan (Inventor)

    2012-01-01

    A stemless ball valve comprising: a right flange; left flange; ball with an axis pin and two travel pins; ball seal on either side of the ball; guide sleeve with inner walls comprising two channels; cartridge guide holder; inner magnetic cartridge; and outer magnetic cartridge. The ball is situated inside of the guide sleeve, and a travel pin is located in each of the two channels. The guide sleeve is situated inside of the cartridge guide holder, which is located adjacent to and outside of the inner magnetic cartridge and secured to the inner magnetic cartridge such that when the inner magnetic cartridge rotates, the cartridge guide holder also rotates. The cartridge guide holder is secured to the guide sleeve such that when the cartridge guide holder rotates, the travel pins move within the channels in the inner walls of the guide sleeve, thereby causing the ball to rotate.

  15. Check valve with poppet damping mechanism

    NASA Technical Reports Server (NTRS)

    Morris, Brian G. (Inventor)

    1993-01-01

    An inline check valve for a flow line is presented where the valve element is guided for inline travel forward and rearward of a valve sealing member and is spring biased to a closed sealing condition. One of the guides for the valve element includes a dashpot bore and plunger member to control the rate of travel of the valve element in either direction as well as provided a guiding function. The dashpot is not anchored to the valve body so that the valve can be functional even if the plunger member becomes jammed in the dashpot.

  16. Check valve with poppet damping mechanism

    NASA Astrophysics Data System (ADS)

    Morris, Brian G.

    1993-08-01

    An inline check valve for a flow line is presented where the valve element is guided for inline travel forward and rearward of a valve sealing member and is spring biased to a closed sealing condition. One of the guides for the valve element includes a dashpot bore and plunger member to control the rate of travel of the valve element in either direction as well as provided a guiding function. The dashpot is not anchored to the valve body so that the valve can be functional even if the plunger member becomes jammed in the dashpot.

  17. Check valve with poppet damping mechanism

    NASA Astrophysics Data System (ADS)

    Morris, Brian G.

    1992-06-01

    An inline check valve for a flow line is presented where the valve element is guided for inline travel forward and rearward of a valve sealing member and is spring biased to a closed sealing condition. One of the guides for the valve element includes a dashpot bore and plunger member to control the rate of travel of the valve element in either direction as well as provided a guiding function. The dashpot is not anchored to the valve body so that the valve can be functional even if the plunger member becomes jammed in the dashpot.

  18. Multi-port valve

    DOEpatents

    Lewin, Keith F.

    1997-04-15

    A multi-port valve for regulating, as a function of ambient air having varying wind velocity and wind direction in an open-field control area, the distribution of a fluid, particularly carbon dioxide (CO.sub.2) gas, in a fluid distribution system so that the control area remains generally at an elevated fluid concentration or level of said fluid. The multi-port valve generally includes a multi-port housing having a plurality of outlets therethrough disposed in a first pattern of outlets and at least one second pattern of outlets, and a movable plate having a plurality of apertures extending therethrough disposed in a first pattern of apertures and at least one second pattern of apertures. The first pattern of apertures being alignable with the first pattern of outlets and the at least one second pattern of apertures being alignable with the second pattern of outlets. The first pattern of apertures has a predetermined orientation with the at least one second pattern of apertures. For an open-field control area subject to ambient wind having a low velocity from any direction, the movable plate is positioned to equally distribute the supply of fluid in a fluid distribution system to the open-field control area. For an open-field control area subject to ambient wind having a high velocity from a given direction, the movable plate is positioned to generally distribute a supply of fluid in a fluid distribution system to that portion of the open-field control area located upwind.

  19. Multi-port valve

    DOEpatents

    Lewin, K.F.

    1997-04-15

    A multi-port valve is described for regulating, as a function of ambient air having varying wind velocity and wind direction in an open-field control area, the distribution of a fluid, particularly carbon dioxide (CO{sub 2}) gas, in a fluid distribution system so that the control area remains generally at an elevated fluid concentration or level of said fluid. The multi-port valve generally includes a multi-port housing having a plurality of outlets there through disposed in a first pattern of outlets and at least one second pattern of outlets, and a movable plate having a plurality of apertures extending there through disposed in a first pattern of apertures and at least one second pattern of apertures. The first pattern of apertures being alignable with the first pattern of outlets and the at least one second pattern of apertures being alignable with the second pattern of outlets. The first pattern of apertures has a predetermined orientation with the at least one second pattern of apertures. For an open-field control area subject to ambient wind having a low velocity from any direction, the movable plate is positioned to equally distribute the supply of fluid in a fluid distribution system to the open-field control area. For an open-field control area subject to ambient wind having a high velocity from a given direction, the movable plate is positioned to generally distribute a supply of fluid in a fluid distribution system to that portion of the open-field control area located upwind. 7 figs.

  20. Ferroelectric Fluid Flow Control Valve

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  1. Fluid relief and check valve

    DOEpatents

    Blaedel, K.L.; Lord, S.C.; Murray, I.

    1986-07-17

    A passive fluid pressure relief and check valve allows the relief pressure to be slaved to a reference pressure independently of the exhaust pressure. The pressure relief valve is embodied by a submerged vent line in a sealing fluid, the relief pressure being a function of the submerged depth. A check valve is embodied by a vertical column of fluid (the maximum back pressure being a function of the height of the column of fluid). The pressure is vented into an exhaust system which keeps the exhaust out of the area providing the reference pressure.

  2. Energy conservation with automatic flow control valves

    SciTech Connect

    Phillips, D.

    1984-12-01

    Automatic flow control valves are offered in a wide range of sizes starting at 1/2 in. with flow rates of 0.5 gpm and up. They are also provided with materials and end connections to meet virtually any fan-coil system requirement. Among these are copper sweat type valves; ductile iron threaded valves; male/female threaded brass valves; and combination flow control/ball valves with union ends.

  3. Paediatric admissions to the British military hospital at Camp Bastion, Afghanistan

    PubMed Central

    Arul, GS; Reynolds, J; DiRusso, S; Scott, A; Bree, S; Templeton, P; Midwinter, MJ

    2012-01-01

    INTRODUCTION International humanitarian law requires emergency medical support for both military personnel and civilians, including children. Here we present a detailed review of paediatric admissions with the pattern of injury and the resources they consume. METHODS All paediatric admissions to the hospital at Camp Bastion between 1 January and 29 April 2011 were analysed prospectively. Data collected included time and date of admission, patient age and weight, mechanism of injury, extent of wounding, treatment, length of hospital stay and discharge destination. RESULTS Eighty-five children (65 boys and 17 girls, median age: 8 years, median weight: 20kg) were admitted. In 63% of cases the indication for admission was battle related trauma and in 31% non-battle trauma. Of the blast injuries, 51% were due to improvised explosive devices. Non-battle emergencies were mainly due to domestic burns (46%) and road traffic accidents (29%). The most affected anatomical area was the extremities (44% of injuries). Over 30% of patients had critical injuries. Operative intervention was required in 74% of cases. The median time to theatre for all patients was 52 minutes; 3 patients with critical injuries went straight to theatre in a median of 7 minutes. A blood transfusion was required in 27 patients; 6 patients needed a massive transfusion. Computed tomography was performed on 62% of all trauma admissions and 40% of patients went to the intensive care unit. The mean length of stay was 2 days (range: 1–26 days) and there were 7 deaths. CONCLUSIONS Paediatric admissions make up a small but significant part of admissions to the hospital at Camp Bastion. The proportion of serious injuries is very high in comparison with admissions to a UK paediatric emergency department. The concentration of major injuries means that lessons learnt in terms of teamwork, the speed of transfer to theatre and massive transfusion protocols could be applied to UK paediatric practice. PMID:22524930

  4. The "Admissions" Side of BCCAT: An Update. Special Report

    ERIC Educational Resources Information Center

    British Columbia Council on Admissions and Transfer, 2008

    2008-01-01

    To spearhead increased emphasis on admissions, the British Columbia Council on Admissions and Transfer (BCCAT) formed an Admissions Committee in Fall 2003. The committee recognized the importance of institutional autonomy in determining admissions policies and processes at each institution. Following initiation of the Student Transitions Project…

  5. Diseases of the Tricuspid Valve

    MedlinePlus

    ... Kawasaki Disease Long Q-T Syndrome Marfan Syndrome Metabolic Syndrome Mitral Valve Prolapse Myocardial Bridge Myocarditis Obstructive Sleep Apnea Pericarditis Peripheral Vascular Disease Rheumatic Fever Sick Sinus Syndrome Silent Ischemia Stroke Sudden ...

  6. What Is Heart Valve Surgery?

    MedlinePlus

    ... valve separates the left ventricle (your heart’s main pumping chamber) and the aorta (the major artery that ... surgery, you‘ll go to an intensive care unit (ICU). •Your family can visit you briefly in ...

  7. Simpler valve for reciprocating engines

    NASA Technical Reports Server (NTRS)

    Akkerman, J. W.

    1978-01-01

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

  8. Mitral Valve Prolapse (For Parents)

    MedlinePlus

    ... Atrial Septal Defect Ventricular Septal Defect Heart and Circulatory System Congenital Heart Defects Getting an EKG (Video) Your Heart & Circulatory System Heart Murmurs Marfan Syndrome Mitral Valve Prolapse EKG ( ...

  9. Bipropellant shut-off valve

    NASA Technical Reports Server (NTRS)

    Smith, J. V.

    1971-01-01

    An advanced design of an all metal, fast response, bipropellant, shut-off valve for use on long duration space missions is reported. The valve provides the flow control capability for a 1,000 lb thrust, bipropellant engine using oxygen difluoride and diborane as propellants. The shutoff seal selection is a soft-on-hard metal concept. The soft seal is a spherical shell that seats against a hard conical seat. Beryllium copper and beryllium nickel seals were selected to seal against an electrolyzed Inconel 718 seat. Poppet shaft sealing is achieved by use of hydroformed, Inconel 718 bellows. Two valve assemblies were fabricated and subjected to a series of tests including leak, response time, flow capacity, dry cycles, water cycles, liquid nitrogen cycles, liquid fluorine cycles, and lead-lag operation cycles. These tests demonstrated the ability of the valve to meet design goals.

  10. Technique of percutaneous laser-assisted valve dilatation for valvar atresia in congenital heart disease.

    PubMed Central

    Rosenthal, E; Qureshi, S A; Kakadekar, A P; Anjos, R; Baker, E J; Tynan, M

    1993-01-01

    OBJECTIVE--To investigate the efficacy and safety of transcatheter laser-assisted valve dilatation for atretic valves in children with congenital heart disease. DESIGN--Prospective clinical study. SETTING--Supraregional paediatric cardiology centre. SUBJECTS--Eleven children (aged 1 day-11 years; weight 2.1-35.7 kg) with atresia of pulmonary (10) or tricuspid (one) valve underwent attempted laser-assisted valve dilatation as part of the staged treatment of their cyanotic heart disease. INTERVENTION--After delineating the atretic valve by angiography and/or echocardiography a 0.018 inch "hot tip" laser wire was used to perforate the atretic valve. Subsequently the valve was dilated with conventional balloon dilatation catheters up to the valve annulus diameter. RESULTS--Laser-assisted valve dilatation was successfully accomplished in nine children. In two neonates with pulmonary valve atresia, intact ventricular septum, and coexistent infundibular atresia the procedure resulted in cardiac tamponade: one died immediately and one later at surgery. During a follow up of 1-17 months (mean 11) two infants with pulmonary valve atresia and intact ventricular septum died (one with congestive cardiac failure). The remainder are either well palliated and do not require further procedures (three), or are awaiting further transcatheter or surgical procedures because of associated defects (four). CONCLUSIONS--Laser-assisted valve dilatation is a promising adjunct to surgery in this high risk group of patients. It may avoid surgery in some patients, and may reduce the number of surgical procedures in those requiring staged operations. Images PMID:8343325

  11. Computer aided detection of endobronchial valves

    NASA Astrophysics Data System (ADS)

    Ochs, Robert A.; Goldin, Jonathan G.; Abtin, Fereidoun; Ghurabi, Raffi; Rao, Ajay; Ahmad, Shama; da Costa, Irene; Brown, Matthew

    2008-03-01

    The ability to automatically detect and monitor implanted devices may serve an important role in patient care and the evaluation of device and treatment efficacy. The purpose of this research was to develop a system for the automated detection of one-way endobronchial valves implanted as part of a clinical trial for less invasive lung volume reduction. Volumetric thin section CT data was obtained for 275 subjects; 95 subjects implanted with 246 devices were used for system development and 180 subjects implanted with 354 devices were reserved for testing. The detection process consisted of pre-processing, pattern-recognition based detection, and a final device selection. Following the pre-processing, a set of classifiers were trained using AdaBoost to discriminate true devices from false positives (such as calcium deposits). The classifiers in the cascade used simple features (the mean or max attenuation) computed near control points relative to a template model of the valve. Visual confirmation of the system output served as the gold standard. FROC analysis was performed for the evaluation; the system could be set so the mean sensitivity was 96.5% with a mean of 0.18 false positives per subject. These generic device modeling and detection techniques may be applicable to other devices and useful for monitoring the placement and function of implanted devices.

  12. Liquid-blocking check valve

    DOEpatents

    Merrill, J.T.

    1982-09-27

    A liquid blocking check valve useful particularly in a pneumatic system utilizing a pressurized liquid fill chamber. The valve includes a floatable ball disposed within a housing defining a chamber. The housing is provided with an inlet aperture disposed in the top of said chamber, and an outlet aperture disposed in the bottom of said chamber in an offset relation to said inlet aperture and in communication with a cutaway side wall section of said housing.

  13. Diesel fuel injection pump with electromagnetic fuel spilling valve having pilot valve providing high responsiveness

    SciTech Connect

    Kobayashi, F.; Ito, Y.; Miyagi, H.

    1986-04-01

    A fuel injection system for a diesel engine is described having a plurality of cylinders coupled to a crankshaft, the fuel injection system consisting of: a housing with a cylindrical bore formed therein; an input shaft mounted coaxially with the bore and rotatable in a predetermined phase relation with the crankshaft of the engine; a plunger slidably mounted in the bore, one end of the plunger defining with the bore a high pressure chamber, and another end of the plunger being rotationally engaged with the input shaft but being free to move axially with respect to the input shaft; means for axially reciprocating the plunger in the bore according to the rotational position of the plunger; means for communicating the high pressure chamber selectively with respective cylinders of the engine according to the rotational position of the plunger substantially only when the plunger is moving in a delivery stroke, axially in a direction to reduce the size of the high pressure chamber; a valve body having an internal chamber communicating with the high pressure chamber, with a vent passage leading from the internal chamber for venting the high pressure chamber; a valve element located in the internal chamber and having an orifice, one side of the orifice communicating with the high pressure chamber; and an electromagnetically operated pilot valve which is selectively electromagnetically driven when electrical energy is supplied thereto so as to close a normally open passage which vents a space on the other side of the orifice remote from the high pressure chamber.

  14. [Infective endocarditis with destruction of the mitral valve annulus and the left atrial posterior wall after cancer chemotherapy].

    PubMed

    Higashi, Rihito; Saso, Masaki; Yamamoto, Tsunehisa; Miyake, Takefumi; Koh, Eisei

    2011-03-01

    The case is reported of a 48-year-old man who underwent distal pancreatectomy, splenectomy, and 4 cycles of postoperative chemotherapy for stage I pancreatic cancer, at the age of 47. Four days after completion of chemotherapy, the patient developed high-grade fever (40 degrees C). In addition, on day 10, he developed disturbance of consciousness, followed by symptoms of shock, which led to emergency hospitalization. On day 4 of admission, the patient was diagnosed as having infective endocarditis and severe mitral valve insufficiency, and was started on antibiotic and heart failure therapy. Surgery was performed on day 16 of admission; the mitral valve infection had spread to the valve cusp and ring, and thence to the posterior wall of the left atrium. After excision of the lesions, the patient underwent mitral valve replacement with a collared prosthesis valve and a translocation procedure. The postoperative course was uneventful, and there has been no recurrence of inflammation or paraprosthetic leakage over the year and 6 months since the operation.

  15. Assessing Practical Intelligence in Business School Admissions: A Supplement to the Graduate Management Admissions Test

    ERIC Educational Resources Information Center

    Hedlund, Jennifer; Wilt, Jeanne M.; Nebel, Kristina L.; Ashford, Susan J.; Sternberg, Robert J.

    2006-01-01

    The Graduate Management Admission Test (GMAT) is the most widely used measure of managerial potential in MBA admissions. GMAT scores, although predictive of grades in business school, leave much of the variance in graduate school performance unexplained. The GMAT also produces disparities in test scores between groups, generating the potential for…

  16. Major Research Efforts of the Law School Admission Council. Law School Admission Research.

    ERIC Educational Resources Information Center

    Hart, Frederick M.; Evans, Franklin R.

    Research conducted by the Law School Admission Council since the development of the Law School Admission Test (LSAT) in 1948 is described. An overview of the research topics is provided, and relevant published reports are cited in 61 footnotes. The following topics of study are discussed: (1) use and validity of traditional predictors of law…

  17. Multiple hospital admissions in a calendar year.

    PubMed

    Newton, J; Goldacre, M

    1993-09-01

    Hospital in-patient workload is routinely measured as episodes of care. We report on the extent to which counts of episodes of care differ from counts of patients treated in different specialties and in different age groups. Linked records of hospital care in a population of 1.9 million people, collected over an 11-year period (1976-1986), were analysed. The all-ages multiple admission ratio (the number of admissions per 100 people admitted in the same specialty and year) varied between specialties from 102 to 171. Medical specialties tended to have higher ratios than surgical ones. The influence of age on multiple admission ratios varied between specialties, although in general the ratios increased with increasing age. There were progressive but small increases in multiple admission ratios over the period studied in a number of specialties but, by and large, stability over time was more striking than any change. The information presented could be used to estimate person-based admission rates from available episode-based data where the former are not available. This should be helpful both in managing hospital resources and in purchasing care on behalf of resident populations. Purchasers in particular should be aware of numbers of people being treated as well as the numbers of episodes of care provided.

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

    PubMed

    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) but those remained stable at third compared with second 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.

  19. Noninvasive valve monitor using alternating electromagnetic field

    DOEpatents

    Eissenberg, David M.; Haynes, Howard D.; Casada, Donald A.

    1993-01-01

    One or more electrical coils are carefully located on the outside of a valve body. An alternating current passing through the coil(s) results in an alternating electromagnetic field being transmitted into the valve body and valve internals. The electromagnetic field varies in intensity and polarity in the valve. As the position of a valve internal part is changed, the electromagnetic field throughout the valve body and its internals is altered. A passive receiver coil carefully located on the outside of the valve body detects the intensity of the electromagnetic field at that location as an induced electrical voltage in the coil. With the change in position of the valve internal part, there is a corresponding change in the induced voltage as a result of the alteration in the alternating electromagnetic field at that location. Changes in the voltage provide an indication of the position and motion of valve internals.

  20. Noninvasive valve monitor using alternating electromagnetic field

    DOEpatents

    Eissenberg, D.M.; Haynes, H.D.; Casada, D.A.

    1993-03-16

    One or more electrical coils are carefully located on the outside of a valve body. An alternating current passing through the coil(s) results in an alternating electromagnetic field being transmitted into the valve body and valve internals. The electromagnetic field varies in intensity and polarity in the valve. As the position of a valve internal part is changed, the electromagnetic field throughout the valve body and its internals is altered. A passive receiver coil carefully located on the outside of the valve body detects the intensity of the electromagnetic field at that location as an induced electrical voltage in the coil. With the change in position of the valve internal part, there is a corresponding change in the induced voltage as a result of the alteration in the alternating electromagnetic field at that location. Changes in the voltage provide an indication of the position and motion of valve internals.

  1. Development of an effective valve packing program

    SciTech Connect

    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.

  2. 46 CFR 52.01-120 - Safety valves and safety relief valves (modifies PG-67 through PG-73).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... than 51mm (2 in.) NPS. (3) On river steam vessels whose boilers are connected in batteries without means of isolating one boiler from another, each battery of boilers shall be treated as a single boiler... weighted safety valves now installed may be continued in use and may be repaired, but when renewals...

  3. 46 CFR 52.01-120 - Safety valves and safety relief valves (modifies PG-67 through PG-73).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... than 51mm (2 in.) NPS. (3) On river steam vessels whose boilers are connected in batteries without means of isolating one boiler from another, each battery of boilers shall be treated as a single boiler... weighted safety valves now installed may be continued in use and may be repaired, but when renewals...

  4. Ischemic mitral valve prolapse

    PubMed Central

    Cristiano, Spadaccio; Nenna, Antonio; Chello, Massimo

    2016-01-01

    Ischemic mitral prolapse (IMP) is a pathologic entity encountered in about one-third among the patients undergoing surgery for ischemic mitral regurgitation (IMR). IMP is generally the result of a papillary muscle injury consequent to myocardial, but the recent literature is progressively unveiling a more complex pathogenesis. The mechanisms underlying its development regards the impairment of one or more components of the mitral apparatus, which comprises the annulus, the chordae tendineae, the papillary muscle and the left ventricular wall. IMP is not only a disorder of valvular function, but also entails coexistent aspects of a geometric disturbance of the mitral valve configuration and of the left ventricular function and dimension and a correct understanding of all these aspects is crucial to guide and tailor the correct therapeutic strategy to be adopted. Localization of prolapse, anatomic features of the prolapsed leaflets and the subvalvular apparatus should be carefully evaluated as also constituting the major determinants defining patient’s outcomes. This review will summarize our current understanding of the pathophysiology and clinical evidence on IMP with a particular focus on the surgical treatment. PMID:28149574

  5. Valve-less microdispenser

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  6. Annular flow diverter valve

    DOEpatents

    Rider, Robert L.

    1980-01-01

    A valve 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 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 servomotor thereby being 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.

  7. [Medical examination prior to trade school admission].

    PubMed

    Hursidić-Radulović, Azra; Decković-Vukres, Vlasta

    2005-01-01

    Regulation on medical examination prior to apprenticeship is built in the Act on Trades and Crafts. Medical examinations of the students before admission to secondary craft schools have been done regularly since 1993. Between 11,000 and 14,000 students are admitted to secondary craft schools in the Republic of Croatia annually. According to statistics, about 10% of students have obvious health problems, about 5% of students have healt problems which vitally limit their capacity in particular crafts. This statistic refers to about 3% of the examined students. Medical examinations of students prior to admission to craft schools represent a particular sort of health capacity examinations. The paper includes applications for the most freqent trades and crafts, and findings of the craft school admission examinations.

  8. [Involuntary admission of addict during early pregnancy].

    PubMed

    Hondius, Adger J K; Stikker, Tineke E; Wennink, J M B Hanneke; Honig, Adriaan

    2012-01-01

    A 30-year-old cocaine-dependent woman was 16 weeks pregnant. Because of possible endangerment of the fetus, an involuntary provisional admission was authorized. Of particular interest is the application of the Dutch Act on Formal Admissions to Psychiatric Hospitals for the primary diagnosis 'addiction' and the fact that the fetus was regarded as a legal 'other'. In severe cases of addiction combined with pregnancy an earlier intervention is needed and arrangement of accelerated legal custody of the newborn before birth should be considered. For the protection of the unborn, we advocate a stricter application of the United Nations Convention on the Rights of the Child. Information for addicted women with preconception counselling can help prevent a compulsory admission.

  9. Pump having pistons and valves made of electroactive actuators

    NASA Technical Reports Server (NTRS)

    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.

  10. Prediction and Reduction of Noise in Pneumatic Bleed Valves

    NASA Astrophysics Data System (ADS)

    Taghavi Nezhad, Shervin

    This study investigates numerically the fluid mechanics and acoustics of pneumatic bleed valves used in turbofan engines. The goal is to characterized the fundamental processes of noise generation and devise strategies for noise reduction. Three different methods are employed for both analysis and redesign of the bleed valve to reduce noise. The bleed valve noise problem is carefully divided into multiple smaller problems. For large separations and tonal noises, the unsteady Reynolds-Averaged Navier-Stokes (URANS) method is utilized. This method is also applied in the re-designing of the bleed valve geometry. For the bleed valve muffler, which is comprised of perforated plates and a honeycomb, a Reynolds-Averaged Navier-Stokes (RANS) method combined with a simplified acoustic analogy is used. The original muffler design is modified to improve noise attenuation. Finally, for sound scattering through perforated plates, a fully implicit linearized Euler solver is developed. The problem of sound interaction with perforated plates is studied from two perspectives. In the first study the effect of high--speed mean flow is considered and it is shown that at Strouhal numbers of around 0.2-0.25 there is an increase in transmitted incident sound. In the second part, the interaction of holes in two--dimensional perforated plates is investigated using three different configurations. The study demonstrates that the hole interaction has a significant impact on sound attenuation, especially at high frequencies.

  11. Spring-Loaded Joule-Thomson Valve

    NASA Technical Reports Server (NTRS)

    Jones, J. A.; Britcliffe, M. J.

    1986-01-01

    Improved design reduces clogging and maintains constant pressure drop as flow rate varies. Spring-Loaded Joule-Thomson Valve pressure drop regulated by spring pushing stainless-steel ball against soft brass seat. Pressure drop remains nearly constant, regardless of helium flow rate and of any gas contaminants frozen on valve seat. Because springloaded J-T valve maintains constant pressure drop, upstream roomtemperature throttle valve adjusts flow rate precisely for any given upstream pressure. In addition, new valve relatively invulnerable to frozen gas contaminants, which clog fixed-orifice J-T valves.

  12. Admission From Nursing Home Residence Increases Acute Mortality After Hip Fractures

    PubMed Central

    van Dijk, Pim A. D.; Bot, Arjan G. J.; Neuhaus, Valentin; Menendez, Mariano E.; Vrahas, Mark S.

    2015-01-01

    Background: Little is known about the effect of preinjury residence on inpatient mortality following hip fracture. This study addressed whether (1) admission from a nursing home residence and (2) admission from another hospital were associated with higher inpatient mortality after a hip fracture. Methods: Using the National Hospital Discharge Survey database, we analyzed an estimated 2 124 388 hip fractures discharges, from 2001 to 2007. Multivariable logistic regression analysis was performed to identify whether admission from a nursing home and admission from another hospital were independent risk factors for inpatient mortality. Our primary null hypothesis is that there is no difference in inpatient mortality rates after hip fracture in patients admitted from a nursing home, compared to other forms of admission. The secondary null hypothesis is that there is no difference in inpatient mortality after hip fracture in patients whose source of admission was another hospital, compared to other sources of admission. Results: Almost 4% of the patients were admitted from a nursing home and 6% from another hospital. The mean age was 79 years and 71% were women. The majority of patients were treated with internal fixation. Admission from a nursing home residence (odds ratio [OR] of 2.1, confidence interval [CI] 1.9-2.3) and prior hospital stay (OR 3.4, CI 3.2-3.7) were associated with a higher risk of inpatient mortality after accounting for other comorbidities and type of treatment. Conclusions: Patients transferred to an acute care hospital from a long-term care facility or another acute care hospital are at particularly high risk of inpatient death. This subset of patients should be considered separately from patients admitted from other sources. Level of Evidence: Prognostic level II. PMID:26328224

  13. Explosive actuated valve

    DOEpatents

    Byrne, Kenneth 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.

  14. BORED AND ASSEMBLED GATE VALVES RECEIVING PROTECTIVE COATING IN THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    BORED AND ASSEMBLED GATE VALVES RECEIVING PROTECTIVE COATING IN THE VALVE PAINT BOOTH OF THE VALVE ASSEMBLY BUILDING. - Stockham Pipe & Fittings Company, Valve Assembly Building, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  15. Analysis of Complex Valve and Feed Systems

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  16. FLUID MECHANICS OF ARTIFICIAL HEART VALVES

    PubMed Central

    Dasi, Lakshmi P; Simon, Helene A; Sucosky, Philippe; Yoganathan, Ajit P

    2009-01-01

    SUMMARY 1. Artificial heart valves have been in use for over five decades to replace diseased heart valves. Since the first heart valve replacement performed with a caged-ball valve, more than 50 valve designs have been developed, differing principally in valve geometry, number of leaflets and material. To date, all artificial heart valves are plagued with complications associated with haemolysis, coagulation for mechanical heart valves and leaflet tearing for tissue-based valve prosthesis. For mechanical heart valves, these complications are believed to be associated with non-physiological blood flow patterns. 2. In the present review, we provide a bird’s-eye view of fluid mechanics for the major artificial heart valve types and highlight how the engineering approach has shaped this rapidly diversifying area of research. 3. Mechanical heart valve designs have evolved significantly, with the most recent designs providing relatively superior haemodynamics with very low aerodynamic resistance. However, high shearing of blood cells and platelets still pose significant design challenges and patients must undergo life-long anticoagulation therapy. Bioprosthetic or tissue valves do not require anticoagulants due to their distinct similarity to the native valve geometry and haemodynamics, but many of these valves fail structurally within the first 10–15 years of implantation. 4. These shortcomings have directed present and future research in three main directions in attempts to design superior artificial valves: (i) engineering living tissue heart valves; (ii) development of advanced computational tools; and (iii) blood experiments to establish the link between flow and blood damage. PMID:19220329

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

    PubMed

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

    2014-01-01

    Today, the quality of mechanical heart valves is quite high, and implantation has become a routine clinical procedure with a low operative mortality (< 5%). However, patients still face the risks of blood cell damage, thromboembolic events, and material failure of the prosthetic device. One mechanism found to be a possible contributor to these adverse effects is cavitation. In vitro, cavitation has been directly demonstrated by visualization and indirectly in vivo by registering of high frequency pressure fluctuations (HFPF). Tilting disc valves are thought of having higher cavitation potential than bileaflet valves due to higher closing velocities. However, the thromboembolic potential seems to be the same. Further studies are therefore needed to investigate the cavitation potential of bileaflet valves in vivo. The post processing of HFPF have shown difficulties when applied on bileaflet vavles due to asynchronous closure of the two leaflets. The aim of this study was therefore to isolate the pressure signature from each leaflet closure and perform cavitation analyses on each component. Six patients were included in the study (St. Jude Medical (n=3) and CarboMedics (n=3); all aortic bileaflet mechanical heart valves). HFPFs were recorded intraoperatively through a hydrophone at the aortic root. The pressure signature relating to the first and second leaflet closure was isolated and cavitation parameters were calculated (RMS after 50 kHz highpass filtering and signal energy). Data were averaged over 30 heart cycles. For all patients both the RMS value and signal energy of the second leaflet closure were higher than for the first leaflet closure. This indicates that the second leaflet closure is most prone to cause cavitation. Therefore, quantifying cavitation based on the HFPF related to the second leaflet closure may suggest that the cavitation potential for bileaflet valves in vivo may be higher than previous studies have suggested.

  18. Large Scale Magnetostrictive Valve Actuator

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

  19. Valve packings conquer fugitive emissions

    SciTech Connect

    1995-11-01

    In the early 1990s, when the US Environmental Protection Agency (EPA; Washington, D.C.) declared its intent to regulate fugitive emissions from valve-stem leakage, much of the chemical process industries (CPI) responded with fear and uncertainty. The biggest fear was that valve packing would not meet the required limits on leak rates and that expensive bellows seals may be required on many applications. The uncertainly was about how much it would cost. Today, for the most part, these concerns have been mitigated. It is estimated that about 80--90% of valves satisfy the emission requirements. The rest need some improvement in their packing systems to meet the regulations. Generally, these valves can be brought within compliance if the packing designers follow a few basic principles: Employ less-pliable outer rings and more-pliable inner rings; and don`t use excessive packing. While interest in valve packing remains high, mechanical seals continue to become more user-friendly. Many of those covered below are designed to run dry, and some can even tolerate high shaft-wobble without damage. Also look for improved flange gaskets and a host of seals to protect bearings. Twenty-one summaries are presented on new products and services.

  20. Titanium in Engine Valve Systems

    NASA Astrophysics Data System (ADS)

    Allison, J. E.; Sherman, A. M.; Bapna, M. R.

    1987-03-01

    Titanium alloys offer a unique combination of high strength-to-weight ratio, good corrosion resistance and favorable high temperature mechanical properties. Still, their relatively high cost has discouraged consideration for widespread use in automotive components. Recent demands for increased fuel economy have led to the consideration of these alloys for use as valve train materials where higher costs might be offset by improvements in performance and fuel economy. Lighter weight valve train components permit the use of lower spring loads, thus reducing friction and increasing fuel economy. Camshaft friction measurements made on a typical small displacement engine indicate that a twoto-four percent increase in fuel economy can be achieved. Valve train components are, however, subject to a severe operating environment, including elevated temperatures, sliding wear and high mechanical loads. This paper discusses the details of alloy and heat treatment selection for optimizing valve performance. When properly manufactured, titanium valves have been shown to withstand very stringent durability testing, indicating the technical feasibility of this approach to fuel economy improvement.