Science.gov

Sample records for one-way valves reveals

  1. One-way water permeable valve via water-based superhydrophobic coatings

    NASA Astrophysics Data System (ADS)

    Mates, Joseph E.; Megaridis, Constantine M.

    2013-11-01

    Spray-cast superhydrophobic coatings have shown promise in commercial applications for fluid management due to their intrinsic low-cost, large-area capabilities and substrate independence (Schutzius et al. 2011). A technique of applying a light (< 2 gsm) water-based superhydrophobic coating on inherently hydrophilic cellulosic substrates to generate a preferred directionality for water absorption and transmission is presented. The mechanism described allows water to pass through a thin treated porous substrate in one direction under negligible pressure, but does not allow water to return from the opposite direction unless much greater pressure is applied. This pressure disparity ``window'' effectively creates a one-way fluid valve, with envisioned applications ranging from personal hygiene products, to oil-water separation and filtration. Combining SEM imaging with theoretical robustness factors (Tuteja et al. 2008), the penetration pressures are found to be tunable for application-specific designs by choosing a substrate based on limiting factors of fiber diameter and spacing. The process can also be modified with the addition of functionalized (e.g. antibacterial, conductive) nanoparticle fillers suited for the desired application.

  2. [A case of ruptured aneurysm in a patient over 90 years of age, successfully treated by clipping with the use of a one-way ball valve for cisternal drainage].

    PubMed

    Kubo, S; Nakata, H; Miyasyo, K; Yoshimine, T

    2000-10-01

    The authors report a case of ruptured aneurysm in a patient in her 90's who was treated by clipping and returned to her independent life after discharge. A 91-year-old woman with a diagnosis of SAH of Hunt & Kosnik Grade III was treated using a conventional clipping operation with cisternal drainage. The cisternal drainage was assembled as a closed system using a newly developed one-way ball valve to regulate the CSF outflow. With this system the patient was able to take any posture and do any movement she wished, not being obligned to stay in bed. Early postoperative rehabilitation was able to be started to prevent pneumonia and muscular atrophy. The drainage was stopped on the 27th postoperative day when the CSF became clear. During the period of drainage, neither valve obstruction nor meningitis was noted. This valve system allows patients under cisternal drainage to move freely. It would be useful, especially when dealing with the elderly, to prevent unwanted complications often caused by postoperative restraint imposed by confinement to bed. PMID:11070911

  3. One-way radiative transfer

    NASA Astrophysics Data System (ADS)

    González-Rodríguez, Pedro; Ilan, Boaz; Kim, Arnold D.

    2016-06-01

    We introduce the one-way radiative transfer equation (RTE) for modeling the transmission of a light beam incident normally on a slab composed of a uniform forward-peaked scattering medium. Unlike the RTE, which is formulated as a boundary value problem, the one-way RTE is formulated as an initial value problem. Consequently, the one-way RTE is much easier to solve. We discuss the relation of the one-way RTE to the Fokker-Planck, small-angle, and Fermi pencil beam approximations. Then, we validate the one-way RTE through systematic comparisons with RTE simulations for both the Henyey-Greenstein and screened Rutherford scattering phase functions over a broad range of albedo, anisotropy factor, optical thickness, and refractive index values. We find that the one-way RTE gives very good approximations for a broad range of optical property values for thin to moderately thick media that have moderately to sharply forward-peaked scattering. Specifically, we show that the error made by the one-way RTE decreases monotonically as the anisotropic factor increases and as the albedo increases. On the other hand, the error increases monotonically as the optical thickness increases and the refractive index mismatch at the boundary increases.

  4. Optimization of one-way wave equations.

    USGS Publications Warehouse

    Lee, M.W.; Suh, S.Y.

    1985-01-01

    The theory of wave extrapolation is based on the square-root equation or one-way equation. The full wave equation represents waves which propagate in both directions. On the contrary, the square-root equation represents waves propagating in one direction only. A new optimization method presented here improves the dispersion relation of the one-way wave equation. -from Authors

  5. One-way unlocalizable quantum discord

    NASA Astrophysics Data System (ADS)

    Xi, Zhengjun; Fan, Heng; Li, Yongming

    2012-05-01

    In this paper, we present the concept of the one-way unlocalizable quantum discord and investigate its properties. We provide a polygamy inequality for it in a tripartite pure quantum system of arbitrary dimension. Several tradeoff relations between the one-way unlocalizable quantum discord and other correlations are given. If the von Neumann measurement is made on a part of the system, we give two expressions of the one-way unlocalizable quantum discord in terms of partial distillable entanglement and quantum disturbance. Finally, we also provide a lower bound for bipartite shareability of quantum correlation beyond entanglement in a tripartite system.

  6. One-way transformation of information

    DOEpatents

    Cooper, James A.

    1989-01-01

    Method and apparatus are provided for one-way transformation of data according to multiplication and/or exponentiation modulo a prime number. An implementation of the invention permits the one way residue transformation, useful in encryption and similar applications, to be implemented by n-bit computers substantially with no increase in difficulty or complexity over a natural transformation thereby, using a modulus which is a power of two.

  7. Logica's one-way VSAT system

    NASA Astrophysics Data System (ADS)

    Barrington-Cook, J. I.

    1991-01-01

    Logica has recently produced the main 'collection and forwarding' element for a comprehensive one-way VSAT system. The system is designed to utilize the extra bandwidth available from direct-to-home broadcasts using the MAC/packet television standard, in order to provide point-to-multipoint data transmission via satellite. The expectation of very large volumes of supply for standard decoders, together with the large amount of bandwidth available, suggest that extremely low cost data transmission may become available. The system is designed to provide the necessary infrastructure to allow this bulk data, low cost approach to be offered for small scale and ad-hoc data transmission.

  8. Microfluidic one-way streets for algae

    NASA Astrophysics Data System (ADS)

    Dunkel, Jorn; Kantsler, Vasily; Polin, Marco; Goldstein, Raymond E.

    2012-02-01

    Controlling locomotion and transport of microorganisms is a key challenge in the development of future biotechnological applications. Here, we demonstrate the use of optimized microfluidic ratchets to rectify the mean swimming direction in suspensions of the unicellular green alga Chlamydomonas reinhardtii, which is a promising candidate for the photosynthetic production of hydrogen. To assess the potential of microfluidic barriers for the manipulation of algal swimming, we studied first the scattering of individual C. reinhardtii from solid boundaries. High-speed imaging reveals the surprising result that these quasi-spherical ``puller''-type microswimmers primarily interact with surfaces via direct flagellar contact, whereas hydrodynamic effects play a subordinate role. A minimal theoretical model, based on run-and-turn motion and the experimentally measured surface-scattering law, predicts the existence of optimal wedge-shaped ratchets that maximize rectification of initially uniform suspensions. We confirm this prediction in experimental measurements with different geometries. Since the mechano-elastic properties of eukaryotic flagella are conserved across many genera, we expect that our results and methods are applicable to a broad class of biflagellate microorganisms.

  9. One-Way Quantum Deficit for 2 ⊗ d Systems

    NASA Astrophysics Data System (ADS)

    Ye, Biao-Liang; Fei, Shao-Ming

    2016-08-01

    We investigate one-way quantum deficit for 2 ⊗ d systems. Analytical expressions of one-way quantum deficit under both von Neumann measurement and weak measurement are presented. As an illustration, qubit-qutrit systems are studied in detail. It is shown that there exists non-zero one-way quantum deficit even quantum entanglement vanishes. Moreover, one-way quantum deficit via weak measurement turns out to be weaker than that via von Neumann measurement. The dynamics of entanglement and one-way quantum deficit under dephasing channels is also investigated.

  10. Comparative Transcriptome Analysis Reveals Substantial Tissue Specificity in Human Aortic Valve

    PubMed Central

    Wang, Jun; Wang, Ying; Gu, Weidong; Ni, Buqing; Sun, Haoliang; Yu, Tong; Gu, Wanjun; Chen, Liang; Shao, Yongfeng

    2016-01-01

    RNA sequencing (RNA-seq) has revolutionary roles in transcriptome identification and quantification of different types of tissues and cells in many organisms. Although numerous RNA-seq data derived from many types of human tissues and cell lines, little is known on the transcriptome repertoire of human aortic valve. In this study, we sequenced the total RNA prepared from two calcified human aortic valves and reported the whole transcriptome of human aortic valve. Integrating RNA-seq data of 13 human tissues from Human Body Map 2 Project, we constructed a transcriptome repertoire of human tissues, including 19,505 protein-coding genes and 4,948 long intergenic noncoding RNAs (lincRNAs). Among them, 263 lincRNAs were identified as novel noncoding transcripts in our data. By comparing transcriptome data among different human tissues, we observed substantial tissue specificity of RNA transcripts, both protein-coding genes and lincRNAs, in human aortic valve. Further analysis revealed that aortic valve-specific lincRNAs were more likely to be recently derived from repetitive elements in the primate lineage, but were less likely to be conserved at the nucleotide level. Expression profiling analysis showed significant lower expression levels of aortic valve-specific protein-coding genes and lincRNA genes, when compared with genes that were universally expressed in various tissues. Isoform-level expression analysis also showed that a majority of mRNA genes had a major isoform expressed in the human aortic valve. To our knowledge, this is the first comparative transcriptome analysis between human aortic valve and other human tissues. Our results are helpful to understand the transcriptome diversity of human tissues and the underlying mechanisms that drive tissue specificity of protein-coding genes and lincRNAs in human aortic valve. PMID:27493474

  11. Comparative Transcriptome Analysis Reveals Substantial Tissue Specificity in Human Aortic Valve.

    PubMed

    Wang, Jun; Wang, Ying; Gu, Weidong; Ni, Buqing; Sun, Haoliang; Yu, Tong; Gu, Wanjun; Chen, Liang; Shao, Yongfeng

    2016-01-01

    RNA sequencing (RNA-seq) has revolutionary roles in transcriptome identification and quantification of different types of tissues and cells in many organisms. Although numerous RNA-seq data derived from many types of human tissues and cell lines, little is known on the transcriptome repertoire of human aortic valve. In this study, we sequenced the total RNA prepared from two calcified human aortic valves and reported the whole transcriptome of human aortic valve. Integrating RNA-seq data of 13 human tissues from Human Body Map 2 Project, we constructed a transcriptome repertoire of human tissues, including 19,505 protein-coding genes and 4,948 long intergenic noncoding RNAs (lincRNAs). Among them, 263 lincRNAs were identified as novel noncoding transcripts in our data. By comparing transcriptome data among different human tissues, we observed substantial tissue specificity of RNA transcripts, both protein-coding genes and lincRNAs, in human aortic valve. Further analysis revealed that aortic valve-specific lincRNAs were more likely to be recently derived from repetitive elements in the primate lineage, but were less likely to be conserved at the nucleotide level. Expression profiling analysis showed significant lower expression levels of aortic valve-specific protein-coding genes and lincRNA genes, when compared with genes that were universally expressed in various tissues. Isoform-level expression analysis also showed that a majority of mRNA genes had a major isoform expressed in the human aortic valve. To our knowledge, this is the first comparative transcriptome analysis between human aortic valve and other human tissues. Our results are helpful to understand the transcriptome diversity of human tissues and the underlying mechanisms that drive tissue specificity of protein-coding genes and lincRNAs in human aortic valve. PMID:27493474

  12. 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.

  13. Mathematical investigation of one-way transform matrix options.

    SciTech Connect

    Cooper, James Arlin

    2006-01-01

    One-way transforms have been used in weapon systems processors since the mid- to late-1970s in order to help recognize insertion of correct pre-arm information while maintaining abnormal-environment safety. Level-One, Level-Two, and Level-Three transforms have been designed. The Level-One and Level-Two transforms have been implemented in weapon systems, and both of these transforms are equivalent to matrix multiplication applied to the inserted information. The Level-Two transform, utilizing a 6 x 6 matrix, provided the basis for the ''System 2'' interface definition for Unique-Signal digital communication between aircraft and attached weapons. The investigation described in this report was carried out to find out if there were other size matrices that would be equivalent to the 6 x 6 Level-Two matrix. One reason for the investigation was to find out whether or not other dimensions were possible, and if so, to derive implementation options. Another important reason was to more fully explore the potential for inadvertent inversion. The results were that additional implementation methods were discovered, but no inversion weaknesses were revealed.

  14. Multipartite distribution property of one way discord beyond measurement

    NASA Astrophysics Data System (ADS)

    Liu, Si-Yuan; Zhang, Yu-Ran; Yang, Wen-Li; Fan, Heng

    2015-03-01

    We investigate the distribution property of one way discord in the multipartite system by introducing the concept of polygamy deficit for one way discord. The difference between one way discord and quantum discord is analogue to the one between entanglement of assistance and entanglement of formation. For tripartite pure states, two kinds of polygamy deficits are presented with the equivalent expressions and physical interpretations regardless of measurement. For four-partite pure states, we provide a condition which makes one way discord polygamy satisfied. In addition, we generalize these results to the case for N-partite pure states. Those results can be applicable to multipartite quantum systems and are complementary to our understanding of the shareability of quantum correlations.

  15. Improved technique for one-way transformation of information

    DOEpatents

    Cooper, J.A.

    1987-05-11

    Method and apparatus are provided for one-way transformation of data according to multiplication and/or exponentiation modulo a prime number. An implementation of the invention permits the one way residue transformation, useful in encryption and similar applications, to be implemented by n-bit computers substantially with no increase in difficulty or complexity over a natural transformation thereby, using a modulus which is a power of two. 9 figs.

  16. Criteria of backscattering in chiral one-way photonic crystals

    NASA Astrophysics Data System (ADS)

    Cheng, Pi-Ju; Chang, Shu-Wei

    2016-03-01

    Optical isolators are important devices in photonic circuits. To reduce the unwanted reflection in a robust manner, several setups have been realized using nonreciprocal schemes. In this study, we show that the propagating modes in a strongly-guided chiral photonic crystal (no breaking of the reciprocity) are not backscattering-immune even though they are indeed insensitive to many types of scatters. Without the protection from the nonreciprocity, the backscattering occurs under certain circumstances. We present a perturbative method to calculate the backscattering of chiral photonic crystals in the presence of chiral/achiral scatters. The model is, essentially, a simplified analogy to the first-order Born approximation. Under reasonable assumptions based on the behaviors of chiral photonic modes, we obtained the expression of reflection coefficients which provides criteria for the prominent backscattering in such chiral structures. Numerical examinations using the finite-element method were also performed and the results agree well with the theoretical prediction. From both our theory and numerical calculations, we find that the amount of backscattering critically depends on the symmetry of scatter cross sections. Strong reflection takes place when the azimuthal Fourier components of scatter cross sections have an order l of 2. Chiral scatters without these Fourier components would not efficiently reflect the chiral photonic modes. In addition, for these chiral propagating modes, disturbances at the most significant parts of field profiles do not necessarily result in the most effective backscattering. The observation also reveals what types of scatters or defects should be avoided in one-way applications of chiral structures in order to minimize the backscattering.

  17. One-way electromagnetic waveguide using multiferroic Fibonacci superlattices

    NASA Astrophysics Data System (ADS)

    Tang, Zhenghua; Lei, Dajun; Huang, Jianquan; Jin, Gui; Qiu, Feng; Yan, Wenyan

    2015-12-01

    The multiferroic Fibonacci superlattices (MFSs) are composed of single-phase multiferroic domains with polarization and magnetization according to the rule of Fibonacci sequence. We propose to construct a one-way electromagnetic waveguide by the MFSs. The forbidden band structures of the MFSs for the forward and backward electromagnetic waves are not completely overlapped, and an obvious translation between them occurs around the fixed point ω bar = 1 with broken time-reversal and space inversion symmetries (TRSIS), which indicates the existence of one-way electromagnetic modes in the MFSs. Transmission spectrum is utilized to present this property and to indicate further one-way electromagnetic modes lying within the polaritonic band gap. The maximum forbidden bandwidth (divided by midgap frequency) of 5.4% for the backward electromagnetic wave (BEW) is found, in which the forward electromagnetic wave (FEW) can pass. The functions of one-way propagation modes and polaritonic band gap integrated into the MFSs can miniaturize the one-way photonic devices. The properties can also be applied to construct compact microwave isolators.

  18. Cooling atoms with a moving one-way barrier

    SciTech Connect

    Schoene, Elizabeth A.; Thorn, Jeremy J.; Steck, Daniel A.

    2010-08-15

    We implement and demonstrate the effectiveness of a cooling scheme using a moving, all-optical, one-way barrier to cool a sample of {sup 87}Rb atoms, achieving nearly a factor of 2 reduction in temperature. The one-way barrier, composed of two focused, Gaussian laser beams, allows atoms incident on one side to transmit, while reflecting atoms incident on the other. The one-way barrier is adiabatically swept through a sample of atoms contained in a far-off-resonant, single-beam, optical dipole trap that forms a nearly harmonic trapping potential. As the barrier moves longitudinally through the potential, atoms become trapped to one side of the barrier with reduced kinetic energy. The adiabatic translation of the barrier leaves the atoms at the bottom of the trapping potential, only minimally increasing their kinetic energy.

  19. Multimode one-way waveguides of large Chern numbers.

    PubMed

    Skirlo, Scott A; Lu, Ling; Soljačić, Marin

    2014-09-12

    Current experimental realizations of the quantum anomalous Hall phase in both electronic and photonic systems have been limited to a Chern number of one. In photonics, this corresponds to a single-mode one-way edge waveguide. Here, we predict quantum anomalous Hall phases in photonic crystals with large Chern numbers of 2, 3, and 4. These new topological phases were found by simultaneously gapping multiple Dirac and quadratic points. We demonstrate a continuously tunable power splitter as a possible application of multimode one-way waveguides. All our findings are readily realizable at microwave frequencies. PMID:25259982

  20. One-way quantum computation with circuit quantum electrodynamics

    SciTech Connect

    Wu Chunwang; Han Yang; Chen Pingxing; Li Chengzu; Zhong Xiaojun

    2010-03-15

    In this Brief Report, we propose a potential scheme to implement one-way quantum computation with circuit quantum electrodynamics (QED). Large cluster states of charge qubits can be generated in just one step with a superconducting transmission line resonator (TLR) playing the role of a dispersive coupler. A single-qubit measurement in the arbitrary basis can be implemented using a single electron transistor with the help of one-qubit gates. By examining the main decoherence sources, we show that circuit QED is a promising architecture for one-way quantum computation.

  1. Noisy one-way quantum computations: The role of correlations

    SciTech Connect

    Chaves, Rafael; Melo, Fernando de

    2011-08-15

    A scheme to evaluate computation fidelities within the one-way model is developed and explored to understand the role of correlations in the quality of noisy quantum computations. The formalism is promptly applied to many computation instances and unveils that a higher amount of entanglement in the noisy resource state does not necessarily imply a better computation.

  2. Detail of one way mirror, mail slot, and electrical box ...

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

    Detail of one way mirror, mail slot, and electrical box at sentry post no. 3, top of east stairs near the end of second floor corridor - March Air Force Base, Strategic Air Command, Combat Operations Center, 5220 Riverside Drive, Moreno Valley, Riverside County, CA

  3. Signal transmission in a Y-shaped one-way chain

    NASA Astrophysics Data System (ADS)

    Liang, Xiaoming; Tang, Ming; Lü, Huaping

    2013-12-01

    It has been found that noise plays a key role to improve signal transmission in a one-way chain of bistable systems [Zhang et al., Phys. Rev. E 58, 2952 (1998)]. We here show that the signal transmission can be sharply improved without the aid of noise, if the one-way chain with a single source node is changed with two source nodes becoming a Y-shaped one-way chain. We further reveal that the enhanced signal transmission in the Y-shaped one-way chain is regulated by coupling strength, and that it is robust to noise perturbation and input signal irregularity. We finally analyze the mechanism of the enhanced signal transmission by the Y-shaped structure.

  4. Topological Phononic Crystals with One-Way Elastic Edge Waves

    NASA Astrophysics Data System (ADS)

    Wang, Pai; Lu, Ling; Bertoldi, Katia

    2015-09-01

    We report a new type of phononic crystals with topologically nontrivial band gaps for both longitudinal and transverse polarizations, resulting in protected one-way elastic edge waves. In our design, gyroscopic inertial effects are used to break the time-reversal symmetry and realize the phononic analogue of the electronic quantum (anomalous) Hall effect. We investigate the response of both hexagonal and square gyroscopic lattices and observe bulk Chern numbers of 1 and 2, indicating that these structures support single and multimode edge elastic waves immune to backscattering. These robust one-way phononic waveguides could potentially lead to the design of a novel class of surface wave devices that are widely used in electronics, telecommunication, and acoustic imaging.

  5. The Mars Observer differential one-way range demonstration

    NASA Technical Reports Server (NTRS)

    Kroger, P. M.; Border, J. S.; Nandi, S.

    1994-01-01

    Current methods of angular spacecraft positioning using station differenced range data require an additional observation of an extragalactic radio source (quasar) to estimate the timing offset between the reference clocks at the two Deep Space Stations. The quasar observation is also used to reduce the effects of instrumental and media delays on the radio metric observable by forming a difference with the spacecraft observation (delta differential one-way range, delta DOR). An experiment has been completed using data from the Global Positioning System satellites to estimate the station clock offset, eliminating the need for the quasar observation. The requirements for direct measurement of the instrumental delays that must be made in the absence of a quasar observation are assessed. Finally, the results of the 'quasar-free' differential one-way range, or DOR, measurements of the Mars Observer spacecraft are compared with those of simultaneous conventional delta DOR measurements.

  6. One-way Ponderomotive Barrier in a Uniform Magnetic Field

    SciTech Connect

    I.Y. Dodin; N.J. Fisch

    2005-02-14

    The possibility of an asymmetric ponderomotive barrier in a nonuniform dc magnetic field by high-frequency radiation near the cyclotron resonance for selected plasma species was contemplated in Physics of Plasmas 11 (November 2004) 5046-5064. Here we show that a similar one-way barrier, which reflects particles incident from one side while transmitting those incident from the opposite side, can be produced also in a uniform magnetic field, entirely due to inhomogeneity of high-frequency drive.

  7. A fault-tolerant one-way quantum computer

    SciTech Connect

    Raussendorf, R. . E-mail: rraussendorf@perimeterinstitute.ca; Harrington, J.; Goyal, K.

    2006-09-15

    We describe a fault-tolerant one-way quantum computer on cluster states in three dimensions. The presented scheme uses methods of topological error correction resulting from a link between cluster states and surface codes. The error threshold is 1.4% for local depolarizing error and 0.11% for each source in an error model with preparation-, gate-, storage-, and measurement errors.

  8. One-way spatial integration of hyperbolic equations

    NASA Astrophysics Data System (ADS)

    Towne, Aaron; Colonius, Tim

    2015-11-01

    In this paper, we develop and demonstrate a method for constructing well-posed one-way approximations of linear hyperbolic systems. We use a semi-discrete approach that allows the method to be applied to a wider class of problems than existing methods based on analytical factorization of idealized dispersion relations. After establishing the existence of an exact one-way equation for systems whose coefficients do not vary along the axis of integration, efficient approximations of the one-way operator are constructed by generalizing techniques previously used to create nonreflecting boundary conditions. When physically justified, the method can be applied to systems with slowly varying coefficients in the direction of integration. To demonstrate the accuracy and computational efficiency of the approach, the method is applied to model problems in acoustics and fluid dynamics via the linearized Euler equations; in particular we consider the scattering of sound waves from a vortex and the evolution of hydrodynamic wavepackets in a spatially evolving jet. The latter problem shows the potential of the method to offer a systematic, convergent alternative to ad hoc regularizations such as the parabolized stability equations.

  9. One-way glass for microwaves using nonreciprocal metamaterials

    NASA Astrophysics Data System (ADS)

    Degiron, A.; Smith, D. R.

    2014-05-01

    We introduce a class of nonreciprocal metamaterials based on composite assemblies of metallic and biased ferrimagnetic elements. We show that such structures act as ultrathin one-way glasses due to the competition between two modes at the surface of the ferrimagnetic elements—a low-loss surface wave that transmits the signal on the other side of the structure and a surface spin-wave resonance that produces strong isolation levels. These findings can be adapted to existing metamaterial geometries, offering a blueprint to achieve unidirectional propagation in a variety of artificial media at radio, microwave, and millimeter wave frequencies.

  10. Universal linear Bogoliubov transformations through one-way quantum computation

    SciTech Connect

    Ukai, Ryuji; Yoshikawa, Jun-ichi; Iwata, Noriaki; Furusawa, Akira; Loock, Peter van

    2010-03-15

    We show explicitly how to realize an arbitrary linear unitary Bogoliubov (LUBO) transformation on a multimode quantum state through homodyne-based one-way quantum computation. Any LUBO transformation can be approximated by means of a fixed, finite-sized, sufficiently squeezed Gaussian cluster state that allows for the implementation of beam splitters (in form of three-mode connection gates) and general one-mode LUBO transformations. In particular, we demonstrate that a linear four-mode cluster state is a sufficient resource for an arbitrary one-mode LUBO transformation. Arbitrary-input quantum states including non-Gaussian states could be efficiently attached to the cluster through quantum teleportation.

  11. Radiochromic leuko dye real time dosimeter, one way optical waveguide

    SciTech Connect

    Kronenberg, S.; McLaughlin, W.L.; Siebentritt, C.R.

    1984-12-18

    A radiochromic leuko dye dosimeter includes a plastic tube containing a solution of a radiochromic dye which is sensitive to ionizing radiation, one end of the tube being closed by a reflective surface, the opposite end of the tube being closed by a transparent plug to form a one-way optical waveguide. Light enters the tube through the transparent end thereof and is reflected back and exits through the transparent end. The intensity of the exiting light is measured to determine radiation induced absorption of the leuko dye.

  12. One-way glass for microwaves using nonreciprocal metamaterials.

    PubMed

    Degiron, A; Smith, D R

    2014-05-01

    We introduce a class of nonreciprocal metamaterials based on composite assemblies of metallic and biased ferrimagnetic elements. We show that such structures act as ultrathin one-way glasses due to the competition between two modes at the surface of the ferrimagnetic elements--a low-loss surface wave that transmits the signal on the other side of the structure and a surface spin-wave resonance that produces strong isolation levels. These findings can be adapted to existing metamaterial geometries, offering a blueprint to achieve unidirectional propagation in a variety of artificial media at radio, microwave, and millimeter wave frequencies. PMID:25353908

  13. One-way helical electromagnetic wave propagation supported by magnetized plasma

    NASA Astrophysics Data System (ADS)

    Yang, Biao; Lawrence, Mark; Gao, Wenlong; Guo, Qinghua; Zhang, Shuang

    2016-02-01

    In this paper we reveal the presence of photonic one-way helical surface states in a simple natural system- magnetized plasma. The application of an external magnetic field to a bulk plasma body not only breaks time-reversal-symmetry but also leads to separation of Equi-Frequency Contour surfaces (EFCs) to form topologically nontrivial gaps in k space. Interestingly, these EFCs support topologically protected surface states. We numerically investigate an interface between magnetized plasma, using a realistic model for parameter dispersion, and vacuum, to confirm the existence of one-way scatter-immune helical surface states. Unlike previous proposals for achieving photonic one-way propagation, our scheme does not require the use of artificial structures and should therefore be simple to implement experimentally.

  14. One-way helical electromagnetic wave propagation supported by magnetized plasma

    PubMed Central

    Yang, Biao; Lawrence, Mark; Gao, Wenlong; Guo, Qinghua; Zhang, Shuang

    2016-01-01

    In this paper we reveal the presence of photonic one-way helical surface states in a simple natural system- magnetized plasma. The application of an external magnetic field to a bulk plasma body not only breaks time-reversal-symmetry but also leads to separation of Equi-Frequency Contour surfaces (EFCs) to form topologically nontrivial gaps in k space. Interestingly, these EFCs support topologically protected surface states. We numerically investigate an interface between magnetized plasma, using a realistic model for parameter dispersion, and vacuum, to confirm the existence of one-way scatter-immune helical surface states. Unlike previous proposals for achieving photonic one-way propagation, our scheme does not require the use of artificial structures and should therefore be simple to implement experimentally. PMID:26883883

  15. Radiochromic leuko dye real time dosimeter, one way optical waveguide

    SciTech Connect

    Kronenberg, S.

    1982-11-15

    This invention relates generally to nuclear radiation dosimetry, and more particularly to a radiochromic leuko dye dosimeter constructed and arranged to measure absorbed radiation doses, such as gamma rays, X-rays and fast neutrons, in real time; viz., as the dose is being delivered. A radiochromic leuko dye dosimeter includes a plastic tube containing a solution of a radiochromic dye which is sensitive to ionizing radiation, one end of the tube being closed by a reflective surface, the opposite end of the tube being closed by a transparent plug to form a one-way optical waveguide. Light enters the tube through the transparent end thereof and is reflected back and exists through the transparent end. The intensity of the existing light is measured to determine radiation induced absorption of the leuko dye.

  16. One way Doppler Extractor. Volume 2: Digital VCO technique

    NASA Technical Reports Server (NTRS)

    Nossen, E. J.; Starner, E. R.

    1974-01-01

    A feasibility analysis and trade-offs for a one-way Doppler extractor using digital VCO techniques is presented. The method of Doppler measurement involves the use of a digital phase lock loop; once this loop is locked to the incoming signal, the precise frequency and hence the Doppler component can be determined directly from the contents of the digital control register. The only serious error source is due to internally generated noise. Techniques are presented for minimizing this error source and achieving an accuracy of 0.01 Hz in a one second averaging period. A number of digitally controlled oscillators were analyzed from a performance and complexity point of view. The most promising technique uses an arithmetic synthesizer as a digital waveform generator.

  17. Finding flows in the one-way measurement model

    SciTech Connect

    Beaudrap, Niel de

    2008-02-15

    The one-way measurement model is a framework for universal quantum computation in which algorithms are partially described by a graph G of entanglement relations on a collection of qubits. A sufficient condition for an algorithm to perform a unitary embedding between two Hilbert spaces is for the graph G, together with input and output I, O vertices I,O is contained in V(G), to have a flow in the sense introduced by Danos and Kashefi [Phys. Rev. A 74, 052310 (2006)]. For the special case of |I|=|O|, using a graph-theoretic characterization, I show that such flows are unique when they exist. This leads to an efficient algorithm for finding flows by a reduction to solved problems in graph theory.

  18. Gate sequence for continuous variable one-way quantum computation

    PubMed Central

    Su, Xiaolong; Hao, Shuhong; Deng, Xiaowei; Ma, Lingyu; Wang, Meihong; Jia, Xiaojun; Xie, Changde; Peng, Kunchi

    2013-01-01

    Measurement-based one-way quantum computation using cluster states as resources provides an efficient model to perform computation and information processing of quantum codes. Arbitrary Gaussian quantum computation can be implemented sufficiently by long single-mode and two-mode gate sequences. However, continuous variable gate sequences have not been realized so far due to an absence of cluster states larger than four submodes. Here we present the first continuous variable gate sequence consisting of a single-mode squeezing gate and a two-mode controlled-phase gate based on a six-mode cluster state. The quantum property of this gate sequence is confirmed by the fidelities and the quantum entanglement of two output modes, which depend on both the squeezing and controlled-phase gates. The experiment demonstrates the feasibility of implementing Gaussian quantum computation by means of accessible gate sequences.

  19. Destination Mars: Colonization via Initial One-way Missions

    NASA Astrophysics Data System (ADS)

    Schulze-Makuch, D.; Davies, P.

    Earth is located in a dangerous part of the universe. Threats to life on Earth are manifold and range from asteroid impacts to supernova explosions and from supervolcano eruptions to human-induced disasters. If the survival of the human species is to be ensured for the long term, then life on Earth has to spread to other planetary bodies. Mars is the most Earth-like planet we currently know and is the second closest planet; further it possesses a moderate surface gravity, an atmosphere, abundant water and carbon dioxide, together with a range of essential minerals. Thus, Mars is ideally suited to be a first colonization target. Here we argue that the most practical way that this can be accomplished is via a series of initial one-way human missions.

  20. One-way ANOVA based on interval information

    NASA Astrophysics Data System (ADS)

    Hesamian, Gholamreza

    2016-08-01

    This paper deals with extending the one-way analysis of variance (ANOVA) to the case where the observed data are represented by closed intervals rather than real numbers. In this approach, first a notion of interval random variable is introduced. Especially, a normal distribution with interval parameters is introduced to investigate hypotheses about the equality of interval means or test the homogeneity of interval variances assumption. Moreover, the least significant difference (LSD method) for investigating multiple comparison of interval means is developed when the null hypothesis about the equality of means is rejected. Then, at a given interval significance level, an index is applied to compare the interval test statistic and the related interval critical value as a criterion to accept or reject the null interval hypothesis of interest. Finally, the method of decision-making leads to some degrees to accept or reject the interval hypotheses. An applied example will be used to show the performance of this method.

  1. One way Doppler extractor. Volume 1: Vernier technique

    NASA Technical Reports Server (NTRS)

    Blasco, R. W.; Klein, S.; Nossen, E. J.; Starner, E. R.; Yanosov, J. A.

    1974-01-01

    A feasibility analysis, trade-offs, and implementation for a One Way Doppler Extraction system are discussed. A Doppler error analysis shows that quantization error is a primary source of Doppler measurement error. Several competing extraction techniques are compared and a Vernier technique is developed which obtains high Doppler resolution with low speed logic. Parameter trade-offs and sensitivities for the Vernier technique are analyzed, leading to a hardware design configuration. A detailed design, operation, and performance evaluation of the resulting breadboard model is presented which verifies the theoretical performance predictions. Performance tests have verified that the breadboard is capable of extracting Doppler, on an S-band signal, to an accuracy of less than 0.02 Hertz for a one second averaging period. This corresponds to a range rate error of no more than 3 millimeters per second.

  2. The Transcriptional Programme of Human Heart Valves Reveals the Natural History of Infective Endocarditis

    PubMed Central

    Benoit, Marie; Thuny, Franck; Le Priol, Yannick; Lepidi, Hubert; Bastonero, Sonia; Casalta, Jean-Paul; Collart, Frédéric; Capo, Christian; Raoult, Didier; Mege, Jean-Louis

    2010-01-01

    Infective endocarditis (IE) is an infectious disease that is mainly caused by Staphylococcus aureus and Streptococcus sp. It usually leads to valvular destruction and vegetation formation. Its pathophysiology is badly understood and likely involves immune and coagulation systems with close interactions with the microorganism. Our objective was to evaluate host response by comparing transcriptional profiles of cardiac valves from IE patients with controls. Hierarchical clustering revealed a signature of IE consisting of 146 genes. Among the 89 up-regulated genes, we identified two genes strongly associated with IE: metalloproteinase 12 (MMP-12) and aquaporin-9, a member of the aquaglyceroporin membrane channel family. The up-regulation of MMP-12 gene is strengthened by the down-modulation of the gene encoding its inhibitor TIMP3. In addition, MMP-12 was expressed in macrophages infiltrating EI valves. We also found that aquaporin-9 was expressed in endothelial cells lining neo-vessel lumen, suggesting that aquaporin-9 might be associated with neovascularization of infected valves leading to tissue oedema secondary to the inflammatory process. The Gene Ontology annotation and the resulting functional classification showed that most up-regulated genes account for recruitment of inflammatory cells in vegetations, angiogenesis and remodelling of endocardium tissue. A network analysis confirmed the involvement of molecules related to the remodelling of endocardium tissue and angiogenesis in IE. It also evidenced the role of caspases, especially that of caspase-9 and intrinsic apoptotic pathway in IE. Based on this study we propose a scenario for the natural history of IE in humans. Some parameters identified in this work could become tools for measuring the disease activity and should be tested as biomarkers for diagnosis or prognosis assessment in future studies. PMID:20126625

  3. Epidemic spreading on one-way-coupled networks

    NASA Astrophysics Data System (ADS)

    Wang, Lingna; Sun, Mengfeng; Chen, Shanshan; Fu, Xinchu

    2016-09-01

    Numerous real-world networks (e.g., social, communicational, and biological networks) have been observed to depend on each other, and this results in interconnected networks with different topology structures and dynamics functions. In this paper, we focus on the scenario of epidemic spreading on one-way-coupled networks comprised of two subnetworks, which can manifest the transmission of some zoonotic diseases. By proposing a mathematical model through mean-field approximation approach, we prove the global stability of the disease-free and endemic equilibria of this model. Through the theoretical and numerical analysis, we obtain interesting results: the basic reproduction number R0 of the whole network is the maximum of the basic reproduction numbers of the two subnetworks; R0 is independent of the cross-infection rate and cross contact pattern; R0 increases rapidly with the growth of inner infection rate if the inner contact pattern is scale-free; in order to eradicate zoonotic diseases from human beings, we must simultaneously eradicate them from animals; bird-to-bird infection rate has bigger impact on the human's average infected density than bird-to-human infection rate.

  4. One-way-ness in the input-saving (Turing) machine

    NASA Astrophysics Data System (ADS)

    de Castro, Alexandre

    2014-12-01

    Currently, a complexity-class problem is proving the existence of one-way permutations: one-to-one and onto maps that are computationally ‘easy’, while their inverses are computationally ‘hard’. In what follows, we make use of Bennett’s algorithm of the reversible Turing machine (quantum information heat engine) to perform a cascade of two controlled-NOT gates to physically create a permutation operation. We show that by running this input-saving (Turing) machine backwards the critical inequality of Landauer’s thermodynamic limit is reversed, which provokes the symmetry-breaking of the quantum circuit based on two successive controlled-NOT quantum gates. This finding reveals that a permutation of controlled-NOT gates becomes one-way, provided that adiabatically immersed in a heat bath, which determines the condition of existence of a thermodynamically non-invertible bijection in polynomial-time, that would otherwise be mathematically invertible. This one-way bijection can also be particularly important because it shows nonlinearities in quantum mechanics, which are detectable by watching that the mathematical reversibility of controlled-NOT gates does not work physically.

  5. Three-dimensional study of a one-way, flexible magnetorheological elastomer-based micro fluid transport system

    NASA Astrophysics Data System (ADS)

    Behrooz, Majid; Gordaninejad, Faramarz

    2016-09-01

    This paper presents a three-dimensional study of a controllable flexible magnetically-activated micropump. The tubular micropump employs magnetically induced deformation of magnetorheological elastomer and one-way flexible conical valves for fluid transport. Three-dimensional magneto–fluid–solid interaction analysis is employed to investigate the performance of the system. The effects of key material, geometric, and magnetic parameters on the effectiveness of the system are examined. It is demonstrated that the proposed system can propel the fluid unidirectionally, and the volume of the transported fluid is significantly affected by some of the design parameters.

  6. 21 CFR 868.5870 - Nonrebreathing valve.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nonrebreathing valve. 868.5870 Section 868.5870...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5870 Nonrebreathing valve. (a) Identification. A nonrebreathing valve is a one-way valve that directs breathing gas flow to the patient...

  7. 21 CFR 868.5870 - Nonrebreathing valve.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nonrebreathing valve. 868.5870 Section 868.5870...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5870 Nonrebreathing valve. (a) Identification. A nonrebreathing valve is a one-way valve that directs breathing gas flow to the patient...

  8. 21 CFR 868.5870 - Nonrebreathing valve.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nonrebreathing valve. 868.5870 Section 868.5870...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5870 Nonrebreathing valve. (a) Identification. A nonrebreathing valve is a one-way valve that directs breathing gas flow to the patient...

  9. 21 CFR 868.5870 - Nonrebreathing valve.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nonrebreathing valve. 868.5870 Section 868.5870...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5870 Nonrebreathing valve. (a) Identification. A nonrebreathing valve is a one-way valve that directs breathing gas flow to the patient...

  10. 21 CFR 868.5870 - Nonrebreathing valve.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nonrebreathing valve. 868.5870 Section 868.5870...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5870 Nonrebreathing valve. (a) Identification. A nonrebreathing valve is a one-way valve that directs breathing gas flow to the patient...

  11. One-way Quantum Deficit and Decoherence for Two-qubit X States

    NASA Astrophysics Data System (ADS)

    Ye, Biao-Liang; Wang, Yao-Kun; Fei, Shao-Ming

    2016-04-01

    We study one-way quantum deficit of two-qubit X states systematically from analytical derivations. An effective approach to compute one-way quantum deficit of two-qubit X states has been provided. Analytical results are presented as for detailed examples. Moreover, we demonstrate the decoherence of one-way quantum deficit under phase damping channel.

  12. 47 CFR 22.589 - One-way or two-way application requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false One-way or two-way application requirements. 22... SERVICES PUBLIC MOBILE SERVICES Paging and Radiotelephone Service One-Way Or Two-Way Mobile Operation § 22.589 One-way or two-way application requirements. In addition to information required by subparts B...

  13. 47 CFR 22.561 - Channels for one-way or two-way mobile operation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Channels for one-way or two-way mobile... CARRIER SERVICES PUBLIC MOBILE SERVICES Paging and Radiotelephone Service One-Way Or Two-Way Mobile Operation § 22.561 Channels for one-way or two-way mobile operation. The following channels are...

  14. 49 CFR 232.403 - Design standards for one-way end-of-train devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Design standards for one-way end-of-train devices. 232.403 Section 232.403 Transportation Other Regulations Relating to Transportation (Continued... Design standards for one-way end-of-train devices. (a) General. A one-way end-of-train device shall...

  15. 47 CFR 22.561 - Channels for one-way or two-way mobile operation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Channels for one-way or two-way mobile... CARRIER SERVICES PUBLIC MOBILE SERVICES Paging and Radiotelephone Service One-Way Or Two-Way Mobile Operation § 22.561 Channels for one-way or two-way mobile operation. The following channels are...

  16. On small set of one-way LOCC indistinguishability of maximally entangled states

    NASA Astrophysics Data System (ADS)

    Wang, Yan-Ling; Li, Mao-Sheng; Zheng, Zhu-Jun; Fei, Shao-Ming

    2016-04-01

    In this paper, we study the one-way local operations and classical communication (LOCC) problem. In {C}^d⊗ {C}^d with d≥ 4, we construct a set of 3lceil √{d}rceil -1 one-way LOCC indistinguishable maximally entangled states which are generalized Bell states. Moreover, we show that there are four maximally entangled states which cannot be perfectly distinguished by one-way LOCC measurements for any dimension d≥ 4.

  17. Experimental demonstration of deterministic one-way quantum computation on a NMR quantum computer

    SciTech Connect

    Ju, Chenyong; Zhu Jing; Peng Xinhua; Chong Bo; Zhou Xianyi; Du Jiangfeng

    2010-01-15

    One-way quantum computing is an important and novel approach to quantum computation. By exploiting the existing particle-particle interactions, we report an experimental realization of the complete process of deterministic one-way quantum Deutsch-Josza algorithm in NMR, including graph state preparation, single-qubit measurements, and feed-forward corrections. The findings in our experiment may shed light on the future scalable one-way quantum computation.

  18. One-way invisible cloak using parity-time symmetric transformation optics.

    PubMed

    Zhu, Xuefeng; Feng, Liang; Zhang, Peng; Yin, Xiaobo; Zhang, Xiang

    2013-08-01

    We propose a one-way invisible cloak using transformation optics of parity-time (PT) symmetric optical materials. At the spontaneous PT-symmetry breaking point, light is scattered only for incidence along one direction since the phase-matching condition is unidirectionally satisfied, making the cloak one-way invisible. Moreover, optical scattering from the one-way cloak can be further engineered to realize more interesting effects, for example, creating a unidirectional optical illusion of the concealed object. PMID:23903152

  19. 47 CFR 90.490 - One-way paging operations in the private services.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false One-way paging operations in the private services. 90.490 Section 90.490 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Paging Operations § 90.490 One-way...

  20. 47 CFR 90.490 - One-way paging operations in the private services.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false One-way paging operations in the private services. 90.490 Section 90.490 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Paging Operations § 90.490 One-way...

  1. On the Experimental Determination of the One-Way Speed of Light

    ERIC Educational Resources Information Center

    Perez, Israel

    2011-01-01

    In this paper the question of the isotropy of the one-way speed of light is addressed from an experimental perspective. In particular, we analyse two experimental methods commonly used in its determination. The analysis is aimed at clarifying the view that the one-way speed of light cannot be determined by techniques in which physical entities…

  2. 49 CFR 232.403 - Design standards for one-way end-of-train devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Design standards for one-way end-of-train devices. (a) General. A one-way end-of-train device shall be... brake pipe pressure variations of ±1 psig; (2) Equipped with a “bleeder valve” that permits the release...) The front device shall have a means for entry of the unique identification code of the rear unit...

  3. A note on one-way quantum deficit and quantum discord

    NASA Astrophysics Data System (ADS)

    Ye, Biao-Liang; Fei, Shao-Ming

    2016-01-01

    One-way quantum deficit and quantum discord are two important measures of quantum correlations. We revisit the relationship between them in two-qubit systems. We investigate the conditions that both one-way quantum deficit and quantum discord have the same optimal measurement ensembles, and demonstrate that one-way quantum deficit can be derived from the quantum discord for a class of X states. Moreover, we give an explicit relation between one-way quantum deficit and entanglement of formation. We show that under phase damping channel both one-way quantum deficit and quantum discord evolve exactly in the same way for four parameter X states. Some examples are presented in details.

  4. Aerodynamic Characteristics of Tracheostomy Speaking Valves.

    ERIC Educational Resources Information Center

    Fornataro-Clerici, Lisa; Zajac, David J.

    1993-01-01

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

  5. One-way membrane trafficking of SOS in receptor-triggered Ras activation.

    PubMed

    Christensen, Sune M; Tu, Hsiung-Lin; Jun, Jesse E; Alvarez, Steven; Triplet, Meredith G; Iwig, Jeffrey S; Yadav, Kamlesh K; Bar-Sagi, Dafna; Roose, Jeroen P; Groves, Jay T

    2016-09-01

    SOS is a key activator of the small GTPase Ras. In cells, SOS-Ras signaling is thought to be initiated predominantly by membrane recruitment of SOS via the adaptor Grb2 and balanced by rapidly reversible Grb2-SOS binding kinetics. However, SOS has multiple protein and lipid interactions that provide linkage to the membrane. In reconstituted-membrane experiments, these Grb2-independent interactions were sufficient to retain human SOS on the membrane for many minutes, during which a single SOS molecule could processively activate thousands of Ras molecules. These observations raised questions concerning how receptors maintain control of SOS in cells and how membrane-recruited SOS is ultimately released. We addressed these questions in quantitative assays of reconstituted SOS-deficient chicken B-cell signaling systems combined with single-molecule measurements in supported membranes. These studies revealed an essentially one-way trafficking process in which membrane-recruited SOS remains trapped on the membrane and continuously activates Ras until being actively removed via endocytosis. PMID:27501536

  6. On the relative performance of one-way and two-way grid nesting

    NASA Astrophysics Data System (ADS)

    Harris, Lucas M.

    Most mesoscale models can be run with either one-way ("parasitic") or two-way ("interactive") grid nesting. This paper presents results from a linear 1D shallow-water model and from 3D simulations of a multicell thunderstorm and of trapped lee waves to determine whether the choice of nesting method can have a significant impact on the solution. In the shallow-water model, two-way nesting was found to be generally superior to one-way nesting. The increased reflection for longer-wavelength disturbances in the one-way case is due to a phase difference between the coarse- and nested-grid solutions at the nested-grid boundary that accumulates because of the difference in numerical phase speeds between the grids. Reflections for two-way nesting may be estimated from the difference in numerical group velocities between the coarse and nested grids, which only becomes large for waves that are poorly-resolved on the coarse grid. The only situation in which one-way nesting performs better than two-way is when very poorly-resolved waves strike the nest boundary; in these cases, using a filter on the coarse-grid values within the sponge zone of an otherwise conventional sponge boundary condition can greatly reduce the reflections caused by two-way nesting. The results were more equivocal for the 3D simulations. Two-way nesting clearly produced smaller precipitation errors than did one-way nesting in the multicell simulations, due to the lack of mismatch errors between the coarse- and nested-grid solutions in the two-way simulations. In the trapped lee-wave simulations, two-way nesting produced lower overall errors than did one-way nesting when a simple interpolation BC was used, but larger errors when the sponge BC was used.

  7. Standing valve

    SciTech Connect

    Coleman, S.B.

    1990-08-28

    This patent discusses an apparatus for removing fluids from a wellbore. It comprises a valve housing fixedly secured to a wellbore tubing string, the housing having perforations and a valve seating surface; a valve stem alignment guide secured to the valve housing; a valve stem adapted for movement in the valve stem alignment guide; and a valve seating device attached to the valve stem and capable of contacting the valve seating surface, thereby preventing fluid flow through the valve housing and past the valve seating surface when the seating device and valve seating surface are in contact.

  8. Bending self-collimated one-way light by using gyromagnetic photonic crystals

    SciTech Connect

    Li, Qing-Bo; Li, Zhen; Wu, Rui-xin

    2015-12-14

    We theoretically demonstrate that electromagnetic waves can self-collimate and propagate unidirectionally in photonic crystals fabricated using semicylindrical ferrite rods in magnetized states. The parity and time-reversal symmetries of such photonic crystals are broken, resulting in a self-collimated one-way body wave within the photonic crystals. By applying the bias magnetic field in a complex configuration, the self-collimated one-way wave beam can be bent into arbitrary trajectories within the photonic crystal, providing an avenue for controlling wave beams.

  9. 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. PMID:25861609

  10. Teaching Principles of One-Way Analysis of Variance Using M&M's Candy

    ERIC Educational Resources Information Center

    Schwartz, Todd A.

    2013-01-01

    I present an active learning classroom exercise illustrating essential principles of one-way analysis of variance (ANOVA) methods. The exercise is easily conducted by the instructor and is instructive (as well as enjoyable) for the students. This is conducive for demonstrating many theoretical and practical issues related to ANOVA and lends itself…

  11. Quantitative Comparison of Three Standardization Methods Using a One-Way ANOVA for Multiple Mean Comparisons

    ERIC Educational Resources Information Center

    Barrows, Russell D.

    2007-01-01

    A one-way ANOVA experiment is performed to determine whether or not the three standardization methods are statistically different in determining the concentration of the three paraffin analytes. The laboratory exercise asks students to combine the three methods in a single analytical procedure of their own design to determine the concentration of…

  12. Perceptual shrinkage of a one-way motion path with high-speed motion

    PubMed Central

    Nakajima, Yutaka; Sakaguchi, Yutaka

    2016-01-01

    Back-and-forth motion induces perceptual shrinkage of the motion path, but such shrinkage is hardly perceived for one-way motion. If the shrinkage is caused by temporal averaging of stimulus position around the endpoints, it should also be induced for one-way motion at higher motion speeds. In psychophysical experiments with a high-speed projector, we tested this conjecture for a one-way motion stimulus at various speeds (4–100 deg/s) along a straight path. Results showed that perceptual shrinkage of the motion path was robustly observed in higher-speed motion (faster than 66.7 deg/s). In addition, the amount of the forwards shift at the onset position was larger than that of the backwards shift at the offset position. These results demonstrate that high-speed motion can induce shrinkage, even for a one-way motion path. This can be explained by the view that perceptual position is represented by the integration of the temporal average of instantaneous position and the motion representation. PMID:27464844

  13. Perceptual shrinkage of a one-way motion path with high-speed motion.

    PubMed

    Nakajima, Yutaka; Sakaguchi, Yutaka

    2016-01-01

    Back-and-forth motion induces perceptual shrinkage of the motion path, but such shrinkage is hardly perceived for one-way motion. If the shrinkage is caused by temporal averaging of stimulus position around the endpoints, it should also be induced for one-way motion at higher motion speeds. In psychophysical experiments with a high-speed projector, we tested this conjecture for a one-way motion stimulus at various speeds (4-100 deg/s) along a straight path. Results showed that perceptual shrinkage of the motion path was robustly observed in higher-speed motion (faster than 66.7 deg/s). In addition, the amount of the forwards shift at the onset position was larger than that of the backwards shift at the offset position. These results demonstrate that high-speed motion can induce shrinkage, even for a one-way motion path. This can be explained by the view that perceptual position is represented by the integration of the temporal average of instantaneous position and the motion representation. PMID:27464844

  14. A Note on Noncentrality Parameters for Contrast Tests in a One-Way Analysis of Variance

    ERIC Educational Resources Information Center

    Liu, Xiaofeng Steven

    2010-01-01

    The noncentrality parameter for a contrast test in a one-way analysis of variance is based on the dot product of 2 vectors whose geometric meaning in a Euclidian space offers mnemonic hints about its constituents. Additionally, the noncentrality parameters for a set of orthogonal contrasts sum up to the noncentrality parameter for the omnibus "F"…

  15. Developing English and Spanish Literacy in a One-Way Spanish Immersion Program

    ERIC Educational Resources Information Center

    Hollingsworth, Lindsay Kay

    2013-01-01

    This quantitative, causal-comparative study examined the possible cause and effect relationship between educational programming, specifically one-way Spanish immersion and traditional English-only, and native English-speaking fifth graders' vocabulary and reading comprehension. Archival data was used to examine students' reading achievement as…

  16. Influence of the Packet Size on the One-Way Delay in 3G Networks

    NASA Astrophysics Data System (ADS)

    Arlos, Patrik; Fiedler, Markus

    We currently observe a rising interest in mobile broadband, which users expect to perform in a similar way as its fixed counterpart. On the other hand, the capacity allocation process on mobile access links is far less transparent to the user; still, its properties need to be known in order to minimize the impact of the network on application performance. This paper investigates the impact of the packet size on the minimal one-way delay for the uplink in third-generation mobile networks. For interactive and real-time applications such as VoIP, one-way delays are of major importance for user perception; however, they are challenging to measure due to their sensitivity to clock synchronisation. Therefore, the paper applies a robust and innovative method to assure the quality of these measurements. Results from measurements from several Swedish mobile operators show that applications can gain significantly in terms of one-way delay from choosing optimal packet sizes. We show that, in certain cases, an increased packet size can improve the one-way delay performance at best by several hundred milliseconds.

  17. Non-linear dynamics of a one-way clutch in belt-pulley systems

    NASA Astrophysics Data System (ADS)

    Zhu, Farong; Parker, R. G.

    2005-01-01

    One-way clutches are frequently used in the serpentine belt accessory drives of automobiles and heavy vehicles. The clutch plays a role similar to a vibration absorber in order to reduce belt/pulley vibration and noise and increase belt life. This paper analyzes a two-pulley system where the driven pulley has a one-way clutch between the pulley and accessory shaft that engages only for positive relative displacement between these components. The belt is modelled with linear springs that transmit torque from the driving pulley to the accessory pulley. The one-way clutch is modelled as a piecewise linear spring with discontinuous stiffness that separates the driven pulley into two degrees of freedom. The harmonic balance method combined with arclength continuation is employed to illustrate the non-linear dynamic behavior of the one-way clutch and determine the stable and unstable periodic solutions for given parameters. The results are confirmed by numerical integration and the bifurcation software AUTO. At the first primary resonance, most of the responses are aperiodic, including quasiperiodic and chaotic solutions. At the second primary resonance, the peak bends to the left with classical softening non-linearity because clutch disengagement decouples the pulley and the accessory over portions of the response period. The dependence on clutch stiffness, excitation amplitude, and inertia ratio between the pulley and accessory is studied to characterize the non-linear dynamics across a range of conditions.

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

    NASA Astrophysics Data System (ADS)

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

    2012-05-01

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

  19. 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.

  20. Distinguishing maximally entangled states by one-way local operations and classical communication

    NASA Astrophysics Data System (ADS)

    Zhang, Zhi-Chao; Feng, Ke-Qin; Gao, Fei; Wen, Qiao-Yan

    2015-01-01

    In this paper, we mainly study the local indistinguishability of mutually orthogonal bipartite maximally entangled states. We construct sets of fewer than d orthogonal maximally entangled states which are not distinguished by one-way local operations and classical communication (LOCC) in the Hilbert space of d ⊗d . The proof, based on the Fourier transform of an additive group, is very simple but quite effective. Simultaneously, our results give a general unified upper bound for the minimum number of one-way LOCC indistinguishable maximally entangled states. This improves previous results which only showed sets of N ≥d -2 such states. Finally, our results also show that previous conjectures in Zhang et al. [Z.-C. Zhang, Q.-Y. Wen, F. Gao, G.-J. Tian, and T.-Q. Cao, Quant. Info. Proc. 13, 795 (2014), 10.1007/s11128-013-0691-9] are indeed correct.

  1. On the experimental determination of the one-way speed of light

    NASA Astrophysics Data System (ADS)

    Pérez, Israel

    2011-07-01

    In this paper the question of the isotropy of the one-way speed of light is addressed from an experimental perspective. In particular, we analyse two experimental methods commonly used in its determination. The analysis is aimed at clarifying the view that the one-way speed of light cannot be determined by techniques in which physical entities close paths. The procedure employed here will provide epistemological tools so that physicists understand that a direct measurement of the speed not only of light but of any physical entity is by no means trivial. Our results shed light on the physics behind the experiments which may be of interest for both physicists with an elemental knowledge in special relativity and philosophers of science.

  2. Observation of Genuine One-Way Einstein-Podolsky-Rosen Steering.

    PubMed

    Wollmann, Sabine; Walk, Nathan; Bennet, Adam J; Wiseman, Howard M; Pryde, Geoff J

    2016-04-22

    Within the hierarchy of inseparable quantum correlations, Einstein-Podolsky-Rosen steering is distinguished from both entanglement and Bell nonlocality by its asymmetry-there exist conditions where the steering phenomenon changes from being observable to not observable, simply by exchanging the role of the two measuring parties. While this one-way steering feature has been previously demonstrated for the restricted class of Gaussian measurements, for the general case of positive-operator-valued measures even its theoretical existence has only recently been settled. Here, we prove, and then experimentally observe, the one-way steerability of an experimentally practical class of entangled states in this general setting. As well as its foundational significance, the demonstration of fundamentally asymmetric nonlocality also has practical implications for the distribution of the trust in quantum communication networks. PMID:27152777

  3. Observation of Genuine One-Way Einstein-Podolsky-Rosen Steering

    NASA Astrophysics Data System (ADS)

    Wollmann, Sabine; Walk, Nathan; Bennet, Adam J.; Wiseman, Howard M.; Pryde, Geoff J.

    2016-04-01

    Within the hierarchy of inseparable quantum correlations, Einstein-Podolsky-Rosen steering is distinguished from both entanglement and Bell nonlocality by its asymmetry—there exist conditions where the steering phenomenon changes from being observable to not observable, simply by exchanging the role of the two measuring parties. While this one-way steering feature has been previously demonstrated for the restricted class of Gaussian measurements, for the general case of positive-operator-valued measures even its theoretical existence has only recently been settled. Here, we prove, and then experimentally observe, the one-way steerability of an experimentally practical class of entangled states in this general setting. As well as its foundational significance, the demonstration of fundamentally asymmetric nonlocality also has practical implications for the distribution of the trust in quantum communication networks.

  4. One-Way Diffusion of Ionic Liquids in a Mixing Process with Water

    NASA Astrophysics Data System (ADS)

    Oikawa, Noriko; Tahara, Daiki; Kurita, Rei

    2016-09-01

    In contrast to the usual diffusive mixing process between two miscible liquids, the ionic liquid [Cnmim][PF6] forms a droplet in water while mixing. The droplet retains a sharp interface with surface tension, gradually decreasing in size until completely mixed with water. This peculiar behavior in the mixing process accompanies one-way diffusion, in which ions diffuse in one direction only from the bulk IL droplet into the bulk continuum of water. The activation energy of the one-way diffusion at the [Cnmim][PF6]/water interface increases with increasing length of the hydrophobic alkyl chains attached to the cation molecules of [Cnmim][PF6]. It is considered that the hydrophobic nanoscale structure observed in [C4mim][PF6] plays an important role in the generation of the droplet and the mixing dynamics.

  5. Semi-device-independent security of one-way quantum key distribution

    SciTech Connect

    Pawlowski, Marcin; Brunner, Nicolas

    2011-07-15

    By testing nonlocality, the security of entanglement-based quantum key distribution (QKD) can be enhanced to being ''device-independent.'' Here we ask whether such a strong form of security could also be established for one-way (prepare and measure) QKD. While fully device-independent security is impossible, we show that security can be guaranteed against individual attacks in a semi-device-independent scenario. In the latter, the devices used by the trusted parties are noncharacterized, but the dimensionality of the quantum systems used in the protocol is assumed to be bounded. Our security proof relies on the analogies between one-way QKD, dimension witnesses, and random-access codes.

  6. One-Way Markov Process Approach to Repeat Times of Large Earthquakes in Faults

    NASA Astrophysics Data System (ADS)

    Tejedor, Alejandro; Gomez, Javier B.; Pacheco, Amalio F.

    2012-11-01

    One of the uses of Markov Chains is the simulation of the seismic cycle in a fault, i.e. as a renewal model for the repetition of its characteristic earthquakes. This representation is consistent with Reid's elastic rebound theory. We propose a general one-way Markovian model in which the waiting time distribution, its first moments, coefficient of variation, and functions of error and alarm (related to the predictability of the model) can be obtained analytically. The fact that in any one-way Markov cycle the coefficient of variation of the corresponding distribution of cycle lengths is always lower than one concurs with observations of large earthquakes in seismic faults. The waiting time distribution of one of the limits of this model is the negative binomial distribution; as an application, we use it to fit the Parkfield earthquake series in the San Andreas fault, California.

  7. Periodic responses of a pulley-belt system with one-way clutch under inertia excitation

    NASA Astrophysics Data System (ADS)

    Ding, Hu

    2015-09-01

    The stable steady-state periodic response of a two-pulley belt drive system coupled with an accessory by a one-way clutch is presented. For the first time, the pulley-belt system is studied under double excitations. Specifically, the dual excitations consist of harmonic motion of the driving pulley and inertia excitation. The belt spans are modeled as axially moving viscoelastic beams by considering belt bending stiffness. Therefore, integro-partial-differential equations are derived for governing the transverse vibrations of the belt spans. Moreover, the transverse vibrations of the moving belt are coupled with the rotation vibrations of the pulleys by nonlinear dynamic tension. For describing the unidirectional decoupling function of the one-way device, rotation vibrations of the driven pulley and accessory are modeled as coupled piecewise ordinary differential equations. In order to eliminate the influence of the boundary of the belt spans, the non-trivial equilibriums of the pulley-belt system are numerically determined. Furthermore, A nonlinear piecewise discrete-continuous dynamical system is derived by introducing a coordinate transform. Coupled vibrations of the pulley-belt system are investigated via the Galerkin truncation. The natural frequencies of the coupled vibrations are obtained by using the fast Fourier transform. Moreover, frequency-response curves are abstracted from time histories. Therefore, resonance areas of the belt spans, the driven pulley and the accessory are presented. Furthermore, validity of the Galerkin method is examined by comparing with the differential and integral quadrature methods (DQM & IQM). By comparing the results with and without one-way device, significant damping effect of clutch on the dynamic response is discovered. Furthermore, the effects of the intensity of the driving pulley excitation and the inertia excitation are studied. Moreover, numerical results demonstrate that the two excitations interact on the steady

  8. Matched Bipartite Digraph Representation of Generalized Dynamical System Formed by One-way Barriers

    NASA Astrophysics Data System (ADS)

    Li, John; Mahoney, John; Mitchell, Kevin; Tom Solomon Collaboration

    2014-03-01

    We studied a dynamical system with stable and unstable manifolds that behave as one-way barriers, instead of separatrices in traditional dynamical system that are two-way barriers. This asymmetry gives rise to a richer dynamical behavior such as the overlapping of basins of attraction. The recently developed Burning Invariant Manifold (BIM) theory took a dynamical system approach to understand front propagation in Advection-Reaction-Diffusion systems, which have BIMs as the one-way barriers. Through numerical simulations under BIM theory, we found that although both unstable and stable BIMs are one-way barriers, unstable BIMs are the ones that we can experimentally observe the fronts converging onto, and the stable BIMs act as the basin boundaries. We further hypothesized a duality relation between the stable and unstable BIMs. Under the duality hypothesis, we developed a mechanism of the behavior of the system by reducing it back to a traditional system based on topology, and we found a simplification of the system by to summarize the topological information into a Matched Bipartite directed graph (MB digraph). This work was supported by the US National Science Foundation under grant PHY-0748828 and NSF Fellowship DGE-0937362.

  9. Well-posedness of one-way wave equations and absorbing boundary conditions

    NASA Technical Reports Server (NTRS)

    Trefethen, L. N.; Halpern, L.

    1985-01-01

    A one-way wave equation is a partial differential which, in some approximate sense, behaves like the wave equation in one direction but permits no propagation in the opposite one. The construction of such equations can be reduced to the approximation of the square root of (1-s sup 2) on -1, 1 by a rational function r(s) = p sub m (s)/q sub n(s). Those rational functions r for which the corresponding one-way wave equation is well-posed are characterized both as a partial differential equation and as an absorbing boundary condition for the wave equation. We find that if r(s) interpolates the square root of (1-s sup 2) at sufficiently many points in (-1,1), then well-posedness is assured. It follows that absorbing boundary conditions based on Pade approximation are well-posed if and only if (m, n) lies in one of two distinct diagonals in the Pade table, the two proposed by Engquist and Majda. Analogous results also hold for one-way wave equations derived from Chebyshev or least-squares approximation.

  10. Burning Invariant Manifold Theory and the Bipartite Digraph Representation of Generalized Dynamical System Formed by One-way Barriers

    NASA Astrophysics Data System (ADS)

    Li, John; Mahoney, John; Mitchell, Kevin; Solomon, Tom

    2013-11-01

    The recently developed Burning Invariant Manifold (BIM) theory took a dynamical system approach to understand front propagation in Advection-Reaction-Diffusion systems and successfully predicted both the short-term and asymptotic front behavior by finding the unstable BIMs which act as barriers to front propagation. Unlike separatrices in traditional dynamical system being two-way barriers, the BIMs are one-way barriers. This asymmetry gives rise to a much richer dynamical behavior than traditional dynamical systems. Through numerical simulations, we found that the stable BIMs are the basin boundaries. Based on the properties of BIM theory, we further derived a theory to investigate a dynamical system consists of one-way barriers and the cooperative behavior of these barriers. This theory reveals the global structure of both stable and unstable BIMs by first using a systematic algorithm to convert the flow to a bipartite digraph and then extracting information of the steady states of fronts and corresponding basins of attraction from the digraph. This work was supported by the US National Science Foundation under grant PHY-0748828 and NSF Fellowship DGE-0937362.

  11. One-way acoustic mirror based on anisotropic zero-index media

    SciTech Connect

    Gu, Zhong-ming; Liang, Bin E-mail: jccheng@nju.edu.cn; Yang, Jing; Cheng, Jian-chun E-mail: jccheng@nju.edu.cn; Zou, Xin-ye; Li, Yong; Yang, Jun

    2015-11-23

    We have designed a one-way acoustic mirror comprising anisotropic zero-index media. For acoustic beam incident at a particular angle, the designed structure behaves like a high-efficient mirror that redirects almost all the incident energy into another direction predicted by the Snell's law, while becoming virtually transparent to beams propagating reversely along this output path. Furthermore, the mirror can be tailored to work at arbitrary incident angle by simply adjusting its geometry. Our design, with undirectional reflection functionality and flexible working angle, may offer possibilities in space isolations and have deep implication in various scenarios like ultrasound imaging or noise control.

  12. Investigation of physical implementation of one-way quantum repeaters with multilevel systems

    NASA Astrophysics Data System (ADS)

    Muralidharan, Sreraman; Zou, Chang-Ling; Li, Linshu; Wen, Jianming; Jiang, Liang

    Error correcting codes of multilevel systems have been shown to be resource efficient for the correction of erasure errors. One way quantum repeaters based on multilevel systems offer ultrafast key generation rates, while consuming lower resources than qubit based schemes (arXiv:1504.08054). On the other hand, they are technologically demanding. Here, we identify the key technological requirements needed for the implementation of quantum repeaters with multilevel systems and propose different experimental techniques that can be used to overcome the difficulties. We propose a generalized Duan-Kimble scheme for the generation of error correcting codes of multilevel systems with time-bin qudits.

  13. Seismic Imaging, One-Way Wave Equations, Pseudodifferential Operators, Path Integrals, and all that Jazz

    NASA Astrophysics Data System (ADS)

    Artoun, Ojenie; David-Rus, Diana; Emmett, Matthew; Fishman, Lou; Fital, Sandra; Hogan, Chad; Lim, Jisun; Lushi, Enkeleida; Marinov, Vesselin

    2006-05-01

    In this report we summarize an extension of Fourier analysis for the solution of the wave equation with a non-constant coefficient corresponding to an inhomogeneous medium. The underlying physics of the problem is exploited to link pseudodifferential operators and phase space path integrals to obtain a marching algorithm that incorporates the backward scattering into the evolution of the wave. This allows us to successfully apply single-sweep, one-way marching methods in inherently two-way environments, which was not achieved before through other methods for this problem.

  14. Two-sample tests and one-way MANOVA for multivariate biomarker data with nondetects.

    PubMed

    Thulin, M

    2016-09-10

    Testing whether the mean vector of a multivariate set of biomarkers differs between several populations is an increasingly common problem in medical research. Biomarker data is often left censored because some measurements fall below the laboratory's detection limit. We investigate how such censoring affects multivariate two-sample and one-way multivariate analysis of variance tests. Type I error rates, power and robustness to increasing censoring are studied, under both normality and non-normality. Parametric tests are found to perform better than non-parametric alternatives, indicating that the current recommendations for analysis of censored multivariate data may have to be revised. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26999657

  15. Demonstration of active feedforward one-way quantum computing with photon-matter hyperentanglement

    NASA Astrophysics Data System (ADS)

    Xu, Xiao-Fan; Bao, Xiao-Hui; Pan, Jian-Wei

    2012-11-01

    We report an optical one-way quantum computing experiment with stationary quantum memory involved. First we create a hybrid four-qubit cluster state with two qubits propagating as photons and the other two stationary and stored in a laser-cooled atomic-ensemble quantum memory, and characterize it with entanglement witnesses and quantum state tomography. Then, by making use of this cluster state and fast operations of electro-optic modulators, we realize memory-assisted feedforward operations and demonstrate deterministic single-qubit rotation as an example.

  16. One way and two way VHF ranging system performance for tracking and data relay applications

    NASA Technical Reports Server (NTRS)

    Bryan, J. W.; Filippi, C. A.

    1972-01-01

    The trajectory of an orbiting spacecraft is determined from an orbit determination program. Two inputs to this program, among others, are the range and range rate relative to some known location. The arithmetic and measurement errors in the determinations of the range, range rate, and range differences were identified and evaluated. These uncertainties are tabulated for one way and two way systems. A comparison of the measurement error contributions illustrate the predominance of thermal noise effects under low power budget conditions, with the other error sources becoming relevent for the high power budget case. The evaluated uncertainties are summarized as root sum squared noise and bias errors.

  17. Observation of broadband unidirectional transmission by fusing the one-way edge states of gyromagnetic photonic crystals.

    PubMed

    Li, Zhen; Wu, Rui-xin; Li, Qing-Bo; Lin, Zhi-fang; Poo, Yin; Liu, Rong-Juan; Li, Zhi-Yuan

    2015-04-20

    We experimentally demonstrate a broadband one-way transmission by merging the operating bands of two types of one-way edge modes that are associated with Bragg scattering and magnetic surface plasmon (MSP) resonance, respectively. By tuning the configuration of gyromagnetic photonic crystals and applied bias magnetic field, the fused bandwidth of unidirectional propagation is up to 2 GHz in microwave frequency range, much larger than either of the individual one-way bandwidth associated with Bragg scattering or MSP resonance. Our scheme for broadband one-way transmission paves the way for the practical applications of one-way transmission. PMID:25969002

  18. Multifunctional magneto-metasurface for terahertz one-way transmission and magnetic field sensing.

    PubMed

    Chen, Sai; Fan, Fei; He, Xiaotong; Chen, Meng; Chang, Shengjiang

    2015-11-01

    A magneto-metasurface is demonstrated for one-way transmission of terahertz (THz) waves and magnetic field sensing. Due to the magneto-optical effect and the asymmetric structure of the transmission system, magnetoplasmon mode splitting for forward and backward THz waves and one-way transmission has been observed in this magneto-metasurface. Significantly, the resonance of the magneto-metasurface has been found that can remain at 0.750 THz at a temperature of 218 K, performing as a stable isolator with an isolation of larger than 30 dB within a magnetic field disturbance from 0.23 to 0.35 T. Also, since the resonance of the magneto-metasurface can be tuned by the different external magnetic fields at a temperature that is higher or lower than 218 K, the magneto-metasurface can work as a highly sensitive magnetic field sensor. The sensitivity of this device reaches S=513.05  GHz·T(-1) when T=230  K. This multifunctional magneto-metasurface has broad potential in THz application systems. PMID:26560571

  19. Derivation of a one-way radiative transfer equation in random media

    NASA Astrophysics Data System (ADS)

    Borcea, Liliana; Garnier, Josselin

    2016-02-01

    We derive from first principles a one-way radiative transfer equation for the wave intensity resolved over directions (Wigner transform of the wave field) in random media. It is an initial value problem with excitation from a source which emits waves in a preferred, forward direction. The equation is derived in a regime with small random fluctuations of the wave speed but long distances of propagation with respect to the wavelength, so that cumulative scattering is significant. The correlation length of the medium and the scale of the support of the source are slightly larger than the wavelength, and the waves propagate in a wide cone with an opening angle less than 180∘, so that the backward and evanescent waves are negligible. The scattering regime is a bridge between that of radiative transfer, where the waves propagate in all directions, and the paraxial regime, where the waves propagate in a narrow angular cone. We connect the one-way radiative transfer equation with the equations satisfied by the Wigner transform of the wave field in these regimes.

  20. Seasonal Ventilation of the Stratosphere: Robust Diagnostics from One-Way Flux Distributions

    NASA Technical Reports Server (NTRS)

    Orbe, Clara; Holzer, Mark; Polvani, Lorenzo M.; Waugh, Darryn W.; Li, Feng; Oman, Luke D.; Newman, Paul A.

    2014-01-01

    We present an analysis of the seasonally varying ventilation of the stratosphere using one-way flux distributions. Robust transport diagnostics are computed using GEOSCCM subject to fixed present-day climate forcings. From the one-way flux, we determine the mass of the stratosphere that is in transit since entry through the tropical tropopause to its exit back into the troposphere, partitioned according to stratospheric residence time and exit location. The seasonalities of all diagnostics are quantified with respect to the month of year (a) when air enters the stratosphere, (b) when the mass of the stratosphere is partitioned, and (c) when air exits back into the troposphere. We find that the return flux, within 3 months since entry, depends strongly on when entry occurred: (34 +/- 10)% more of the air entering the stratosphere in July leaves poleward of 45 deg N compared to air that enters in January. The month of year when the air mass is partitioned is also found to be important: The stratosphere contains about six times more air of tropical origin during late summer and early fall that will leave poleward of 45 deg within 6 months since entering the stratosphere compared to during late winter to late spring. When the entire mass of the air that entered the stratosphere at the tropics regardless of its residence time is considered, we find that (51 +/- 1)% and (39 +/- 2)% will leave poleward of 10 deg in the Northern Hemisphere (NH) and Southern Hemisphere (SH), respectively.

  1. Demonstration of orbit determination for the Lunar Reconnaissance Orbiter using one-way laser ranging data

    NASA Astrophysics Data System (ADS)

    Bauer, S.; Hussmann, H.; Oberst, J.; Dirkx, D.; Mao, D.; Neumann, G. A.; Mazarico, E.; Torrence, M. H.; McGarry, J. F.; Smith, D. E.; Zuber, M. T.

    2016-09-01

    We used one-way laser ranging data from International Laser Ranging Service (ILRS) ground stations to NASA's Lunar Reconnaissance Orbiter (LRO) for a demonstration of orbit determination. In the one-way setup, the state of LRO and the parameters of the spacecraft and all involved ground station clocks must be estimated simultaneously. This setup introduces many correlated parameters that are resolved by using a priori constraints. Moreover the observation data coverage and errors accumulating from the dynamical and the clock modeling limit the maximum arc length. The objective of this paper is to investigate the effect of the arc length, the dynamical and modeling accuracy and the observation data coverage on the accuracy of the results. We analyzed multiple arcs using lengths of 2 and 7 days during a one-week period in Science Mission phase 02 (SM02, November 2010) and compared the trajectories, the post-fit measurement residuals and the estimated clock parameters. We further incorporated simultaneous passes from multiple stations within the observation data to investigate the expected improvement in positioning. The estimated trajectories were compared to the nominal LRO trajectory and the clock parameters (offset, rate and aging) to the results found in the literature. Arcs estimated with one-way ranging data had differences of 5-30 m compared to the nominal LRO trajectory. While the estimated LRO clock rates agreed closely with the a priori constraints, the aging parameters absorbed clock modeling errors with increasing clock arc length. Because of high correlations between the different ground station clocks and due to limited clock modeling accuracy, their differences only agreed at the order of magnitude with the literature. We found that the incorporation of simultaneous passes requires improved modeling in particular to enable the expected improvement in positioning. We found that gaps in the observation data coverage over 12 h (≈6 successive LRO orbits

  2. Acoustic one-way metasurfaces: Asymmetric Phase Modulation of Sound by Subwavelength Layer

    PubMed Central

    Jiang, Xue; Liang, Bin; Zou, Xin-ye; Yang, Jing; Yin, Lei-lei; Yang, Jun; Cheng, Jian-chun

    2016-01-01

    We theoretically design and numerically demonstrate an acoustic one-way metasurface, which is a planar and acoustically subwavelength layer behaving like a nearly-reflectionless surface with arbitrary wave-steering capability for incident wave impinging on one side, while virtually blocking the reversed wave. The underlying mechanism is based on an asymmetric phase modulation by coupling a phase array and a near-zero-index medium. We exemplify a metastructure-based implementation by combining the hybrid metastuctures and labyrinthine structures. Moreover, the performance of the proposed implementation is demonstrated via three distinct phenomena of anomalous refraction, wave splitting and conversion of propagation wave to surface wave. Our findings may offer more possibilities for sound manipulation and improve the application potential of acoustic artificial devices in situations such as ultrasonic imaging and therapy. PMID:27305973

  3. A one way Doppler tracking system for satellite to satellite tracking

    NASA Technical Reports Server (NTRS)

    Bryan, J. W.; Lynn, J. J.

    1973-01-01

    An S-band tracking system employing one way Doppler applicable to the tracking and data relay system (TDRS) was evaluated. This evaluation is limited to the measurement system parameters. The analysis assumes state-of-the-art components such as spacecraft oscillator long term stability of one part in 10 to the 8th power and ground station oscillator stability of one part in 10 to the 11th power. Signal characteristics comparable with the present ranging systems are utilized in the analysis. Predicated upon measurement system parameters, position uncertainties for the low orbiting spacecraft vary from 5 meters to 2 kilometers along track, 4 meters to 1 kilometer cross track, and 1 meter to 180 meters radially depending upon the tracking geometry and the high satellite position and velocity error assumptions.

  4. Maximum likelihood analysis for heteroscedastic one-way random effects ANOVA in interlaboratory studies.

    PubMed

    Vangel, M G; Rukhin, A L

    1999-03-01

    This article presents results for the maximum likelihood analysis of several groups of measurements made on the same quantity. Following Cochran (1937, Journal of the Royal Statistical Society 4(Supple), 102-118; 1954, Biometrics 10, 101-129; 1980, in Proceedings of the 25th Conference on the Design of Experiments in Army Research, Development and Testing, 21-33) and others, this problem is formulated as a one-way unbalanced random-effects ANOVA with unequal within-group variances. A reparametrization of the likelihood leads to simplified computations, easier identification and interpretation of multimodality of the likelihood, and (through a non-informative-prior Bayesian approach) approximate confidence regions for the mean and between-group variance. PMID:11318146

  5. Acoustic one-way metasurfaces: Asymmetric Phase Modulation of Sound by Subwavelength Layer

    NASA Astrophysics Data System (ADS)

    Jiang, Xue; Liang, Bin; Zou, Xin-Ye; Yang, Jing; Yin, Lei-Lei; Yang, Jun; Cheng, Jian-Chun

    2016-06-01

    We theoretically design and numerically demonstrate an acoustic one-way metasurface, which is a planar and acoustically subwavelength layer behaving like a nearly-reflectionless surface with arbitrary wave-steering capability for incident wave impinging on one side, while virtually blocking the reversed wave. The underlying mechanism is based on an asymmetric phase modulation by coupling a phase array and a near-zero-index medium. We exemplify a metastructure-based implementation by combining the hybrid metastuctures and labyrinthine structures. Moreover, the performance of the proposed implementation is demonstrated via three distinct phenomena of anomalous refraction, wave splitting and conversion of propagation wave to surface wave. Our findings may offer more possibilities for sound manipulation and improve the application potential of acoustic artificial devices in situations such as ultrasonic imaging and therapy.

  6. One-way quantum key distribution: Simple upper bound on the secret key rate

    SciTech Connect

    Moroder, Tobias; Luetkenhaus, Norbert; Curty, Marcos

    2006-11-15

    We present a simple method to obtain an upper bound on the achievable secret key rate in quantum key distribution (QKD) protocols that use only unidirectional classical communication during the public-discussion phase. This method is based on a necessary precondition for one-way secret key distillation; the legitimate users need to prove that there exists no quantum state having a symmetric extension that is compatible with the available measurements results. The main advantage of the obtained upper bound is that it can be formulated as a semidefinite program, which can be efficiently solved. We illustrate our results by analyzing two well-known qubit-based QKD protocols: the four-state protocol and the six-state protocol.

  7. An energy-conserving one-way coupled mode propagation model.

    PubMed

    Abawi, Ahmad T

    2002-01-01

    The equations of motion for pressure and displacement fields in a waveguide have been used to derive an energy-conserving, one-way coupled mode propagation model. This model has three important properties: First, since it is based on the equations of motion, rather than the wave equation, instead of two coupling matrices, it only contains one coupling matrix. Second, the resulting coupling matrix is anti-symmetric, which implies that the energy among modes is conserved. Third, the coupling matrix can be computed using the local modes and their depth derivatives. The model has been applied to two range-dependent cases: Propagation in a wedge, where range dependence is due to variations in water depth and propagation through internal waves, where range dependence is due to variations in water sound speed. In both cases the solutions are compared with those obtained from the parabolic equation (PE) method. PMID:11831790

  8. Strong entanglement causes low gate fidelity in inaccurate one-way quantum computation

    SciTech Connect

    Morimae, Tomoyuki

    2010-06-15

    We study how entanglement among the register qubits affects the gate fidelity in the one-way quantum computation if a measurement is inaccurate. We derive an inequality that shows that the mean gate fidelity is upper bounded by a decreasing function of the magnitude of the error of the measurement and the amount of the entanglement between the measured qubit and other register qubits. The consequence of this inequality is that, for a given amount of entanglement, which is theoretically calculated once the algorithm is fixed, we can estimate from this inequality how small the magnitude of the error should be in order not to make the gate fidelity below a threshold, which is specified by a technical requirement in a particular experimental setup or by the threshold theorem of the fault-tolerant quantum computation.

  9. Transport properties of MOPhC/metal one-way waveguide

    SciTech Connect

    Eyderman, Sergey; Kuzmiak, Vladimir

    2011-10-03

    We have demonstrated numerically that the interface between metal and uniformly magnetized 2D photonic crystal(PC) fabricated from a transparent dielectric magneto-optic(MO) material possesses a one-way frequency range where only a forward propagating surface plasmon polariton mode is allowed to propagate. By using a simple theoretical model we have shown that nonreciprocity is introduced by the MO properties of the PC. Transport properties of the structures within this frequency range have been investigated by FDTD method which enables to calculating propagation of EM waves through media with full tensorial MO permittivity. We found that in the presence of a time-dependent external magnetic field interesting features associated with the redistribution of the EM field appear.

  10. Acoustic one-way metasurfaces: Asymmetric Phase Modulation of Sound by Subwavelength Layer.

    PubMed

    Jiang, Xue; Liang, Bin; Zou, Xin-Ye; Yang, Jing; Yin, Lei-Lei; Yang, Jun; Cheng, Jian-Chun

    2016-01-01

    We theoretically design and numerically demonstrate an acoustic one-way metasurface, which is a planar and acoustically subwavelength layer behaving like a nearly-reflectionless surface with arbitrary wave-steering capability for incident wave impinging on one side, while virtually blocking the reversed wave. The underlying mechanism is based on an asymmetric phase modulation by coupling a phase array and a near-zero-index medium. We exemplify a metastructure-based implementation by combining the hybrid metastuctures and labyrinthine structures. Moreover, the performance of the proposed implementation is demonstrated via three distinct phenomena of anomalous refraction, wave splitting and conversion of propagation wave to surface wave. Our findings may offer more possibilities for sound manipulation and improve the application potential of acoustic artificial devices in situations such as ultrasonic imaging and therapy. PMID:27305973

  11. Surface plasmon polaritons one-way mode converter based on parity-time symmetry broken system

    NASA Astrophysics Data System (ADS)

    Yan, Xiang-An; Liu, Hanchen; Zhu, Changjun

    2016-03-01

    In this paper, we have proposed a novel periodic surface plasmon polariton (SPP) waveguide to realize a one-way mode converter which is based on a parity-time (PT) symmetry broken system, and it converts the fundamental TM mode to the first-order TM mode in only forward direction. Periodic gain potentials are put in place to construct the system mentioned in periodic SPP waveguide. Further, as the mode converter contains gain and loss material, light signals will be amplified when it propagates forward, and they will be attenuated toward when they propagate backward. The unidirectional mode converter has wide applications in nonlinearity induced isolation, mode insensitive element and on-chip mode locked laser.

  12. Demonstration of a controlled-phase gate for continuous-variable one-way quantum computation.

    PubMed

    Ukai, Ryuji; Yokoyama, Shota; Yoshikawa, Jun-ichi; van Loock, Peter; Furusawa, Akira

    2011-12-16

    We experimentally demonstrate a controlled-phase gate for continuous variables using a cluster-state resource of four optical modes. The two independent input states of the gate are coupled with the cluster in a teleportation-based fashion. As a result, one of the entanglement links present in the initial cluster state appears in the two unmeasured output modes as the corresponding entangling gate acting on the input states. The genuine quantum character of this gate becomes manifest and is verified through the presence of entanglement at the output for a product two-mode coherent input state. By combining our gate with the recently reported module for single-mode Gaussian operations [R. Ukai et al., Phys. Rev. Lett. 106, 240504 (2011)], it is possible to implement any multimode Gaussian operation as a fully measurement-based one-way quantum computation. PMID:22243056

  13. An experiment to measure the one-way velocity of propagation of electromagnetic radiation

    NASA Technical Reports Server (NTRS)

    Kolen, P.; Torr, D. G.

    1982-01-01

    An experiment involving commercially available instrumentation to measure the velocity of the earth with respect to absolute space is described. The experiment involves the measurement of the one-way propagation velocity of electromagnetic radiation down a high-quality coaxial cable. It is demonstrated that the experiment is both physically meaningful and exceedingly simple in concept and in implementation. It is shown that with currently available commercial equipment one might expect to detect a threshold value for the component of velocity of the earth's motion with respect to absolute space in the equatorial plane of approximately 10 km/s, which greatly exceeds the velocity resolution required to detect the motion of the solar system with respect to the center of the galaxy.

  14. An attack aimed at active phase compensation in one-way phase-encoded QKD systems

    NASA Astrophysics Data System (ADS)

    Dong, Zhao-Yue; Yu, Ning-Na; Wei, Zheng-Jun; Wang, Jin-Dong; Zhang, Zhi-Ming

    2014-08-01

    Phase drift is an inherent problem in one-way phase-encoded quantum key distribution (QKD) systems. Although combining passive with active phase compensation (APC) processes can effectively compensate for the phase drift, the security problems brought about by these processes are rarely considered. In this paper, we point out a security hole in the APC process and put forward a corresponding attack scheme. Under our proposed attack, the quantum bit error rate (QBER) of the QKD can be close to zero for some conditions. However, under the same conditions the ratio r of the key "0" and the key "1" which Bob (the legal communicators Alice and Bob) gets is no longer 1:1 but 2:1, which may expose Eve (the eavesdropper). In order to solve this problem, we modify the resend strategy of the attack scheme, which can force r to reach 1 and the QBER to be lower than the tolerable QBER.

  15. Plug valve

    DOEpatents

    Wordin, John J.

    1989-01-01

    An improved plug valve wherein a novel shape for the valve plug and valve chamber provide mating surfaces for improved wear characteristics. The novel shape of the valve plug is a frustum of a body of revolution of a curved known as a tractrix, a solid shape otherwise known as a peudosphere.

  16. Integratable quarter-wave plates enable one-way angular momentum conversion.

    PubMed

    Liang, Yao; Zhang, Fengchun; Gu, Jiahua; Huang, Xu Guang; Liu, Songhao

    2016-01-01

    Nanophotonic waveguides are the building blocks of integrated photonics. To date, while quarter-wave plates (QWPs) are widely used as common components for a wide range of applications in free space, there are almost no reports of Integratable QWPs being able to manipulate the angular momentum (AM) of photons inside nanophotonic waveguides. Here, we demonstrate two kinds of Integratable QWPs respectively based on the concept of abrupt phase change and birefringence effect. The orientation of the equivalent optical axis of an Integratable QWP is designable. Remarkably, a combination of two integratable QWPs with different equivalent optical axes leads to an integrated system that performances one-way AM conversion. Moreover, this system can be used as a point source that can excite different patterns on a metal surface via directional excitation of surface plasmon polaritons (SPP). These results allow for the control of AM of light in nanophotonic waveguides, which are crucial for various applications with limited physical space, such as on-chip bio-sensing and integrated quantum information processing. PMID:27102332

  17. Integratable quarter-wave plates enable one-way angular momentum conversion

    NASA Astrophysics Data System (ADS)

    Liang, Yao; Zhang, Fengchun; Gu, Jiahua; Huang, Xu Guang; Liu, Songhao

    2016-04-01

    Nanophotonic waveguides are the building blocks of integrated photonics. To date, while quarter-wave plates (QWPs) are widely used as common components for a wide range of applications in free space, there are almost no reports of Integratable QWPs being able to manipulate the angular momentum (AM) of photons inside nanophotonic waveguides. Here, we demonstrate two kinds of Integratable QWPs respectively based on the concept of abrupt phase change and birefringence effect. The orientation of the equivalent optical axis of an Integratable QWP is designable. Remarkably, a combination of two integratable QWPs with different equivalent optical axes leads to an integrated system that performances one-way AM conversion. Moreover, this system can be used as a point source that can excite different patterns on a metal surface via directional excitation of surface plasmon polaritons (SPP). These results allow for the control of AM of light in nanophotonic waveguides, which are crucial for various applications with limited physical space, such as on-chip bio-sensing and integrated quantum information processing.

  18. Two-factor authentication system based on optical interference and one-way hash function

    NASA Astrophysics Data System (ADS)

    He, Wenqi; Peng, Xiang; Meng, Xiangfeng; Liu, Xiaoli

    2012-10-01

    We present a two-factor authentication method to verify the personal identification who tries to access an optoelectronic system. This method is based on the optical interference principle and the traditional one-way Hash function (e.g. MD5). The authentication process is straightforward, the phase key and the password-controlled phase lock of one user are loading on two Spatial Light Modulators (SLMs) in advance, by which two coherent beams are modulated and then interference with each other at the output plane leading to an output image. By comparing the output image with all the standard certification images in the database, the system can thus verify the user's identity. However, the system designing process involves an iterative Modified Phase Retrieval Algorithm (MPRA). For an uthorized user, a phase lock is first created based on a "Digital Fingerprint (DF)", which is the result of a Hash function on a preselected user password. The corresponding phase key can then be determined by use of the phase lock and a designated standard certification image. Note that the encode/design process can only be realized by digital means while the authentication process could be achieved digitally or optically. Computer simulations were also given to validate the proposed approach.

  19. One-way approximation for the simulation of weak shock wave propagation in atmospheric flows.

    PubMed

    Gallin, Louis-Jonardan; Rénier, Mathieu; Gaudard, Eric; Farges, Thomas; Marchiano, Régis; Coulouvrat, François

    2014-05-01

    A numerical scheme is developed to simulate the propagation of weak acoustic shock waves in the atmosphere with no absorption. It generalizes the method previously developed for a heterogeneous medium [Dagrau, Rénier, Marchiano, and Coulouvrat, J. Acoust. Soc. Am. 130, 20-32 (2011)] to the case of a moving medium. It is based on an approximate scalar wave equation for potential, rewritten in a moving time frame, and separated into three parts: (i) the linear wave equation in a homogeneous and quiescent medium, (ii) the effects of atmospheric winds and of density and speed of sound heterogeneities, and (iii) nonlinearities. Each effect is then solved separately by an adapted method: angular spectrum for the wave equation, finite differences for the flow and heterogeneity corrections, and analytical method in time domain for nonlinearities. To keep a one-way formulation, only forward propagating waves are kept in the angular spectrum part, while a wide-angle parabolic approximation is performed on the correction terms. The numerical process is validated in the case of guided modal propagation with a shear flow. It is then applied to the case of blast wave propagation within a boundary layer flow over a flat and rigid ground. PMID:24815240

  20. Numerical Analysis of Stress on Pump Blade by One-Way Coupled Fluid-Structure Simulation

    NASA Astrophysics Data System (ADS)

    Kobayashi, Katsutoshi; Ono, Shigeyoshi; Harada, Ichiro; Chiba, Yoshimasa

    A mixed-flow pump with an unshrouded impeller was computed by a one-way coupled fluid-structure simulation to evaluate a prediction accuracy of stress and analyze a flow pattern which caused the largest stress. The stress occurring around a blade root was predicted by a numerical simulation and compared with an experimental one. Five flow rates, Q/Qbep=0,40,70,100 and 120% were simulated and the predicted stresses at all flow rates agreed with the experimental ones within -11˜+6% accuracy. The largest stress occurred around a blade root on a pressure side of blade surface at all flow rates. The stress became largest at 70% flow rate. A flow pattern around the blade was analyzed to investigate how the largest stress occurred at 70% flow rate. It was found in this study that a flow separation occurred around a leading edge on a suction side of blade surface at 70% flow rate and the largest load was acting on an outside region of blade.

  1. Integratable quarter-wave plates enable one-way angular momentum conversion

    PubMed Central

    Liang, Yao; Zhang, Fengchun; Gu, Jiahua; Huang, Xu Guang; Liu, Songhao

    2016-01-01

    Nanophotonic waveguides are the building blocks of integrated photonics. To date, while quarter-wave plates (QWPs) are widely used as common components for a wide range of applications in free space, there are almost no reports of Integratable QWPs being able to manipulate the angular momentum (AM) of photons inside nanophotonic waveguides. Here, we demonstrate two kinds of Integratable QWPs respectively based on the concept of abrupt phase change and birefringence effect. The orientation of the equivalent optical axis of an Integratable QWP is designable. Remarkably, a combination of two integratable QWPs with different equivalent optical axes leads to an integrated system that performances one-way AM conversion. Moreover, this system can be used as a point source that can excite different patterns on a metal surface via directional excitation of surface plasmon polaritons (SPP). These results allow for the control of AM of light in nanophotonic waveguides, which are crucial for various applications with limited physical space, such as on-chip bio-sensing and integrated quantum information processing. PMID:27102332

  2. Manipulating one-way space wave and its refraction by time-reversal and parity symmetry breaking

    PubMed Central

    Poo, Yin; He, Cheng; Xiao, Chao; Lu, Ming-Hui; Wu, Rui-Xin; Chen, Yan-Feng

    2016-01-01

    One-way transmission and negative refraction are the exotic wave properties founded in photonic crystals which attract a great attention due to their promising applications in photonic devices. How to integrate such two phenomena in one material or device is interesting and valuable. In this work, we theoretically and experimentally demonstrate that one-way electromagnetic space wave can be realized by means of two-dimensional magnetic photonic crystals. Simultaneously breaking the time-reversal and parity symmetries of the magnetic photonic crystals designed, we observe oblique incident space wave propagating one-way in the magnetic photonic crystals with positive or negative refraction occurring at interfaces, which can be manipulated upon the incident angle and operating frequency. Our work may offer a potential platform to realize some exotic photoelectronic and microwave devices such as one-way imaging and one-way cloaking. PMID:27387438

  3. Manipulating one-way space wave and its refraction by time-reversal and parity symmetry breaking

    NASA Astrophysics Data System (ADS)

    Poo, Yin; He, Cheng; Xiao, Chao; Lu, Ming-Hui; Wu, Rui-Xin; Chen, Yan-Feng

    2016-07-01

    One-way transmission and negative refraction are the exotic wave properties founded in photonic crystals which attract a great attention due to their promising applications in photonic devices. How to integrate such two phenomena in one material or device is interesting and valuable. In this work, we theoretically and experimentally demonstrate that one-way electromagnetic space wave can be realized by means of two-dimensional magnetic photonic crystals. Simultaneously breaking the time-reversal and parity symmetries of the magnetic photonic crystals designed, we observe oblique incident space wave propagating one-way in the magnetic photonic crystals with positive or negative refraction occurring at interfaces, which can be manipulated upon the incident angle and operating frequency. Our work may offer a potential platform to realize some exotic photoelectronic and microwave devices such as one-way imaging and one-way cloaking.

  4. Manipulating one-way space wave and its refraction by time-reversal and parity symmetry breaking.

    PubMed

    Poo, Yin; He, Cheng; Xiao, Chao; Lu, Ming-Hui; Wu, Rui-Xin; Chen, Yan-Feng

    2016-01-01

    One-way transmission and negative refraction are the exotic wave properties founded in photonic crystals which attract a great attention due to their promising applications in photonic devices. How to integrate such two phenomena in one material or device is interesting and valuable. In this work, we theoretically and experimentally demonstrate that one-way electromagnetic space wave can be realized by means of two-dimensional magnetic photonic crystals. Simultaneously breaking the time-reversal and parity symmetries of the magnetic photonic crystals designed, we observe oblique incident space wave propagating one-way in the magnetic photonic crystals with positive or negative refraction occurring at interfaces, which can be manipulated upon the incident angle and operating frequency. Our work may offer a potential platform to realize some exotic photoelectronic and microwave devices such as one-way imaging and one-way cloaking. PMID:27387438

  5. One-way-coupling simulation of cavitation accompanied by high-speed droplet impact

    NASA Astrophysics Data System (ADS)

    Kondo, Tomoki; Ando, Keita

    2016-03-01

    Erosion due to high-speed droplet impact is a crucial issue in industrial applications. The erosion is caused by the water-hammer loading on material surfaces and possibly by the reloading from collapsing cavitation bubbles that appear within the droplet. Here, we simulate the dynamics of cavitation bubbles accompanied by high-speed droplet impact against a deformable wall in order to see whether the bubble collapse is violent enough to give rise to cavitation erosion on the wall. The evolution of pressure waves in a single water (or gelatin) droplet to collide with a deformable wall at speed up to 110 m/s is inferred from simulations of multicomponent Euler flow where phase changes are not permitted. Then, we examine the dynamics of cavitation bubbles nucleated from micron/submicron-sized gas bubble nuclei that are supposed to exist inside the droplet. For simplicity, we perform Rayleigh-Plesset-type calculations in a one-way-coupling manner, namely, the bubble dynamics are determined according to the pressure variation obtained from the Euler flow simulation. In the simulation, the preexisting bubble nuclei whose size is either micron or submicron show large growth to submillimeters because tension inside the droplet is obtained through interaction of the pressure waves and the droplet interface; this supports the possibility of having cavitation due to the droplet impact. It is also found, in particular, for the case of cavitation arising from very small nuclei such as nanobubbles, that radiated pressure from the cavitation bubble collapse can overwhelm the water-hammer pressure directly created by the impact. Hence, cavitation may need to be accounted for when it comes to discussing erosion in the droplet impact problem.

  6. Check valve

    SciTech Connect

    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.

  7. 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.

  8. Valve Disease

    MedlinePlus

    ... the need for heart valve surgery. Percutaneous Interventions Balloon valvuloplasty is a procedure that may be used ... procedure works on valves in the same way balloon angioplasty does on the arteries. Like angioplasty, it ...

  9. Theory of wave propagation in magnetized near-zero-epsilon metamaterials: evidence for one-way photonic states and magnetically switched transparency and opacity.

    PubMed

    Davoyan, Arthur R; Engheta, Nader

    2013-12-20

    We study propagation of transverse-magnetic electromagnetic waves in the bulk and at the surface of a magnetized epsilon-near-zero (ENZ) medium in a Voigt configuration. We reveal that in a certain range of material parameters novel regimes of wave propagation emerge; we show that the transparency of the medium can be altered with the magnetization leading either to magnetically induced Hall opacity or Hall transparency of the ENZ. In our theoretical study, we demonstrate that surface waves at the interface between either a transparent or an opaque Hall medium and a homogeneous medium may, under certain conditions, be predominantly one way. Moreover, we predict that one-way photonic surface states may exist at the interface of an opaque Hall ENZ and a regular metal, giving rise to the possibility for backscattering immune wave propagation and isolation. PMID:24483756

  10. Theory of Wave Propagation in Magnetized Near-Zero-Epsilon Metamaterials: Evidence for One-Way Photonic States and Magnetically Switched Transparency and Opacity

    NASA Astrophysics Data System (ADS)

    Davoyan, Arthur R.; Engheta, Nader

    2013-12-01

    We study propagation of transverse-magnetic electromagnetic waves in the bulk and at the surface of a magnetized epsilon-near-zero (ENZ) medium in a Voigt configuration. We reveal that in a certain range of material parameters novel regimes of wave propagation emerge; we show that the transparency of the medium can be altered with the magnetization leading either to magnetically induced Hall opacity or Hall transparency of the ENZ. In our theoretical study, we demonstrate that surface waves at the interface between either a transparent or an opaque Hall medium and a homogeneous medium may, under certain conditions, be predominantly one way. Moreover, we predict that one-way photonic surface states may exist at the interface of an opaque Hall ENZ and a regular metal, giving rise to the possibility for backscattering immune wave propagation and isolation.

  11. Heart valve surgery

    MedlinePlus

    Valve replacement; Valve repair; Heart valve prosthesis; Mechanical valves, Prosthetic valves ... place. The main types of new valves are: Mechanical -- made of man-made materials, such as metal ( ...

  12. 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.

  13. 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.

  14. Cryptorchidism in boys with posterior urethral valves.

    PubMed

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

    1980-07-01

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

  15. 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.

  16. Oviduct-Embryo Interactions in Cattle: Two-Way Traffic or a One-Way Street?

    PubMed

    Maillo, Veronica; Gaora, Peadar Ó; Forde, Niamh; Besenfelder, Urban; Havlicek, Vitezslav; Burns, Gregory W; Spencer, Thomas E; Gutierrez-Adan, Alfonso; Lonergan, Patrick; Rizos, Dimitrios

    2015-06-01

    This study examined the effect of the presence of single or multiple embryos on the transcriptome of the bovine oviduct. In experiment 1, cyclic (nonbred, n = 6) and pregnant (artificially inseminated, n = 11) heifers were slaughtered on Day 3 after estrus, and the ampulla and isthmic regions of the oviduct ipsilateral to the corpus luteum were separately flushed. Oviductal epithelial cells from the isthmus region, in which all oocytes/embryos were located, were snap-frozen for microarray analysis. In experiment 2, heifers were divided into cyclic (nonbred, n = 6) or pregnant (multiple embryo transfer, n = 10) groups. In vitro-produced presumptive zygotes were transferred endoscopically to the ipsilateral oviduct on Day 1.5 postestrus (n = 50 zygotes/heifer). Heifers were slaughtered on Day 3, and oviductal isthmus epithelial cells were recovered for RNA sequencing. Microarray analysis in experiment 1 failed to detect any difference in the transcriptome of the oviductal isthmus induced by the presence of a single embryo. In experiment 2, following multiple embryo transfer, RNA sequencing revealed 278 differentially expressed genes, of which 123 were up-regulated and 155 were down-regulated in pregnant heifers. Most of the down-regulated genes were related to immune function. In conclusion, the presence of multiple embryos in the oviduct resulted in the detection of differentially expressed genes in the oviductal isthmus; failure to detect changes in the oviduct transcriptome in the presence of a single embryo may be due to the effect being local and undetectable under the conditions of this study. PMID:25926440

  17. Adjusting for Unequal Variances when Comparing Means in One-Way and Two-Way Fixed Effects ANOVA Models.

    ERIC Educational Resources Information Center

    Wilcox, Rand R.

    1989-01-01

    Two methods of handling unequal variances in the two-way fixed effects analysis of variance (ANOVA) model are described. One is based on an improved Wilcox (1988) method for the one-way model, and the other is an extension of G. S. James' (1951) second order method. (TJH)

  18. FORTRAN IV Program for One-Way Analysis of Variance with A Priori or A Posteriori Mean Comparisons

    ERIC Educational Resources Information Center

    Fordyce, Michael W.

    1977-01-01

    A flexible Fortran program for computing one way analysis of variance is described. Requiring minimal core space, the program provides a variety of useful group statistics, all summary statistics for the analysis, and all mean comparisons for a priori or a posteriori testing. (Author/JKS)

  19. Heteroscedastic Tests Statistics for One-Way Analysis of Variance: The Trimmed Means and Hall's Transformation Conjunction

    ERIC Educational Resources Information Center

    Luh, Wei-Ming; Guo, Jiin-Huarng

    2005-01-01

    To deal with nonnormal and heterogeneous data for the one-way fixed effect analysis of variance model, the authors adopted a trimmed means method in conjunction with Hall's invertible transformation into a heteroscedastic test statistic (Alexander-Govern test or Welch test). The results of simulation experiments showed that the proposed technique…

  20. One Way or Another

    NASA Technical Reports Server (NTRS)

    Zazzali, Christian

    2003-01-01

    Even experienced project managers can t anticipate every potential problem. Part of planning ahead should include allowing oneself the flexibility to rethink the plan and improvise if necessary. Unique solutions to problems sometimes create a set of new problems unique in nature as well. In dealing with sudden changes in planning, try to consider what other elements of the project will be affected, but don t second guess yourself into a state of inaction because you can t anticipate every contingency.

  1. 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

  2. Spacecraft Doppler tracking with possible violations of LLI and LPI: upper bounds from one-way measurements on MEX

    NASA Astrophysics Data System (ADS)

    Xie, Yi; Huang, Yong

    2015-10-01

    We analyze the post-fit residuals of one-way Doppler tracking data from the Mars Express (MEX) spacecraft to test possible violations of local Lorentz invariance (LLI) and local position invariance (LPI). These one-way Doppler observations were carried out on 2011 August 7 for about 20 minutes at Sheshan Station of Shanghai Astronomical Observatory in China. These downlink signals were sent by MEX for telemetry at X-band. Because we are not able to decode the data in the form of telemetry and separate them from the carrier frequency, this makes the post-fit residuals of the Doppler data degrade to the level of 0.1 m s-1. Even so, the residuals can still impose upper bounds on LLI and LPI at 10-1, which is consistent with the prediction based on our analysis of the detectability. Although the upper bounds given by three-way Doppler tracking of MEX are better than those obtained in the present work, one-way Doppler measurements still provide a unique chance to test possible violations of LLI and LPI far from the ground stations.

  3. 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.

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

    PubMed

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

    2010-03-01

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

  5. Experimental demonstration of counteracting imperfect sources in a practical one-way quantum-key-distribution system

    SciTech Connect

    Xu Fangxing; Zhang Yang; Zhou Zheng; Chen Wei; Han Zhengfu; Guo Guangcan

    2009-12-15

    In a practical quantum-key-distribution system, photon source and small operational errors cause intensity fluctuations inevitably, which cannot be ignored for a precise estimation on the single-photon fraction. In this paper, we demonstrated an efficient three-intensity decoy method scheme on top of the one-way Faraday-Michelson Interferometric system, combining an active monitoring with existing commercial apparatus to inspect fluctuations instantly. With this faithful detection for the upper bound of the fluctuation, the secure quantum key distribution is unconditionally realized with whatever type of intensity errors, which declares the utility and potential of decoy theory and active monitoring for quantum key distribution in practical use.

  6. 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.

  7. Resource cost results for one-way entanglement distillation and state merging of compound and arbitrarily varying quantum sources

    SciTech Connect

    Boche, H. Janßen, G.

    2014-08-01

    We consider one-way quantum state merging and entanglement distillation under compound and arbitrarily varying source models. Regarding quantum compound sources, where the source is memoryless, but the source state an unknown member of a certain set of density matrices, we continue investigations begun in the work of Bjelaković et al. [“Universal quantum state merging,” J. Math. Phys. 54, 032204 (2013)] and determine the classical as well as entanglement cost of state merging. We further investigate quantum state merging and entanglement distillation protocols for arbitrarily varying quantum sources (AVQS). In the AVQS model, the source state is assumed to vary in an arbitrary manner for each source output due to environmental fluctuations or adversarial manipulation. We determine the one-way entanglement distillation capacity for AVQS, where we invoke the famous robustification and elimination techniques introduced by Ahlswede. Regarding quantum state merging for AVQS we show by example that the robustification and elimination based approach generally leads to suboptimal entanglement as well as classical communication rates.

  8. Problem: Heart Valve Regurgitation

    MedlinePlus

    ... Pressure High Blood Pressure Tools & Resources Stroke More Problem: Heart Valve Regurgitation Updated:May 26,2016 What ... content was last reviewed May 2016. Heart Valve Problems and Disease • Home • About Heart Valves • Heart Valve ...

  9. Problem: Heart Valve Stenosis

    MedlinePlus

    ... Pressure High Blood Pressure Tools & Resources Stroke More Problem: Heart Valve Stenosis Updated:Aug 10,2016 About ... content was last reviewed May 2016. Heart Valve Problems and Disease • Home • About Heart Valves • Heart Valve ...

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

    PubMed

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

    2016-04-01

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

  11. 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.

  12. Comparing One-way and Two-way Coupled Hydrometeorological Forecasting Systems for Flood Forecasting in the Mediterranean Region

    NASA Astrophysics Data System (ADS)

    Givati, Amir; Gochis, David; Rummler, Thomas; Kunstmann, Harald; Yu, Wei

    2016-04-01

    A pair of hydro-meteorological modeling systems were calibrated and evaluated for the Ayalon basin in central Israel to assess the advantages and limitations of one-way versus two-way coupled modeling systems for flood prediction. The models used included the Hydrological Engineering Center-Hydrological Modeling System (HEC-HMS) model and the Weather Research and Forecasting (WRF) Hydro modeling system. The models were forced by observed, interpolated precipitation from rain-gauges within the basin, and with modeled precipitation from the WRF atmospheric model. Detailed calibration and evaluation was carried out for two major winter storms in January and December 2013. Then both modeling systems were executed and evaluated in an operational mode for the full 2014/2015 rainy season. Outputs from these simulations were compared to observed measurements from hydrometric stations at the Ayalon basin outlet. Various statistical metrics were employed to quantify and analyze the results: correlation, Root Mean Square Error (RMSE) and the Nash-Sutcliffe (NS) efficiency coefficient. Foremost, the results presented in this study highlight the sensitivity of hydrological responses to different sources of precipitation data, and less so, to hydrologic model formulation. With observed precipitation data both calibrated models closely simulated the observed hydrographs. The two-way coupled WRF/WRF-Hydro modeling system produced improved both the precipitation and hydrological simulations as compared to the one-way WRF simulations. Findings from this study suggest that the use of two-way atmospheric-hydrological coupling has the potential to improve precipitation and, therefore, hydrological forecasts for early flood warning applications. However more research needed in order to better understand the land-atmosphere coupling mechanisms driving hydrometeorological processes on a wider variety precipitation and terrestrial hydrologic systems.

  13. 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.

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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.

  20. Development and application of one-way elastic wave propagators in generally-anisotropic, heterogeneous, three-dimensional media

    NASA Astrophysics Data System (ADS)

    Angus, Douglas A.

    A finite-difference narrow-angle one-way wave equation is implemented and is applied to various wave propagation problems to verify the method as well as to study frequency-dependent three-component waveform effects. The narrow-angle wave equation is the most approximate, yet most computationally practical, of the one-way wave equations derived by Thomson (1999). Although the vector narrow-angle wave equation is limited to a certain propagation distance, it is still a viable and powerful modelling approach to wave propagation in three-dimensional elastic media. A FORTRAN finite-difference code is developed that is second-order accurate in the lateral and forward propagation direction and requires only three extrapolation planes to be stored during each propagation step. Numerical analysis of the finite-difference algorithm indicates that the scheme is stable for appropriate initial conditions and, for the propagation path-lengths of interest, angular range of forward propagation and source-pulse spectral content, numerical grid-anisotropy is minimal. The narrow-angle propagator is sufficiently accurate for angles up to +/-15° to the preferred direction of propagation and is stable within singular regions of slowness space. For reasonable velocity gradients, the travel-times and amplitudes of transmitted and converted body-waves are in good agreement with an exact reference solution. The conical-point singularity is the main focus of the homogeneous, anisotropic wave propagation examples, because it represents the most extreme anisotropic singularity and poses the greatest difficulty for ray-based methods. The results of wave propagation along the acoustic axis display characteristic and potentially diagnostic waveform effects, such as wavefront folding and tearing, merging and splitting pulses, growth of anomalous components and bipolar waveforms. The results of wave propagation in isotropic heterogeneous media are consistent with various published results. Some

  1. A one-way coupled, Euler-Lagrangian simulation of bubble coalescence in a turbulent pipe flow

    NASA Astrophysics Data System (ADS)

    Mattson, Michael; Mahesh, Krishnan

    2011-11-01

    A bubble coalescence model is developed using an Euler-Lagrangian approach for unstructured grids. The Eulerian carrier fluid is solved using large-eddy simulation (LES) and the Lagrangian particle motion is solved using one-way coupled equations relating the turbulent motion of the carrier fluid to the forces on each discrete bubble. The collision process is deterministic; bubble-bubble collisions are assumed to be binary and are modeled using a hard-sphere approach. A stochastic approach is used to model coalescence, with the probability of coalescence being a function of the bubble-bubble interaction timescale and the time to drain fluid between the colliding bubbles. Coalescence in a bubbly, turbulent pipe flow without buoyancy is simulated with conditions similar to a microgravity experiment by Colin, Fabre and Dukler [Int. J. Multiphase Flow (1991) 17:533-544] and excellent agreement of bubble size distribution is obtained between simulation and experiment. With increasing downstream distance, the number density of bubbles decreases due to coalescence and the average probability of coalescence decreases slightly due to an increase in overall bubble size. Supported by the U.S. Office of Naval Research under ONR Grant N00014-07-1-0420.

  2. Assessing Fan Flutter Stability in the Presence of Inlet Distortion Using One-way and Two-way Coupled Methods

    NASA Technical Reports Server (NTRS)

    Herrick, Gregory P.

    2014-01-01

    Concerns regarding noise, propulsive efficiency, and fuel burn are inspiring aircraft designs wherein the propulsive turbomachines are partially (or fully) embedded within the airframe; such designs present serious concerns with regard to aerodynamic and aeromechanic performance of the compression system in response to inlet distortion. Previously, a preliminary design of a forward-swept high-speed fan exhibited flutter concerns in cleaninlet flows, and the present author then studied this fan further in the presence of off-design distorted in-flows. Continuing this research, a three-dimensional, unsteady, Navier-Stokes computational fluid dynamics code is again applied to analyze and corroborate fan performance with clean inlet flow and now with a simplified, sinusoidal distortion of total pressure at the aerodynamic interface plane. This code, already validated in its application to assess aerodynamic damping of vibrating blades at various flow conditions using a one-way coupled energy-exchange approach, is modified to include a two-way coupled time-marching aeroelastic simulation capability. The two coupling methods are compared in their evaluation of flutter stability in the presence of distorted in-flows.

  3. Investigation of crystal structures of one-way shape memory Nitinol wire actuators for active steerable needle

    NASA Astrophysics Data System (ADS)

    Honarvar, Mohammad; Konh, Bardia; Hutapea, Parsaoran

    2015-04-01

    Due to its outstanding properties of Nitinol, known as shape memory and superelasticity, Nitinol wires have been used as actuators in many medical devices. For the medical applications, it is critical to have a consistent strain response of Nitinol wires. This work focuses on studying the effect of parameters such as biased stress, maximum temperature, and wire diameters that influence the strain response of Nitinol wires. Specifically, Nitinol phase transformations were studied from microstructural point of view. The crystal structures of one-way shape memory Nitinol wires of various diameters under different thermomechanical loading conditions were studied using X-Ray Diffraction (XRD) method. The location and intensity of characteristic peaks were determined prior and after the thermomechanical loading cycles. It was observed that Nitinol wires of diameters less than 0.19 mm exhibit unrecovered strain while heated to the range of 70ºC to 80ºC in a thermal cycle, whereas no unrecovered strains were found in larger wires. The observation was supported by the XRD patterns where the formation of R-phase crystal structure was showed in wire diameters less than 0.19 mm at room temperature.

  4. A one-way coupled atmospheric-hydrological modeling system with combination of high-resolution and ensemble precipitation forecasting

    NASA Astrophysics Data System (ADS)

    Wu, Zhiyong; Wu, Juan; Lu, Guihua

    2015-11-01

    Coupled hydrological and atmospheric modeling is an effective tool for providing advanced flood forecasting. However, the uncertainties in precipitation forecasts are still considerable. To address uncertainties, a one-way coupled atmospheric-hydrological modeling system, with a combination of high-resolution and ensemble precipitation forecasting, has been developed. It consists of three high-resolution single models and four sets of ensemble forecasts from the THORPEX Interactive Grande Global Ensemble database. The former provides higher forecasting accuracy, while the latter provides the range of forecasts. The combined precipitation forecasting was then implemented to drive the Chinese National Flood Forecasting System in the 2007 and 2008 Huai River flood hindcast analysis. The encouraging results demonstrated that the system can clearly give a set of forecasting hydrographs for a flood event and has a promising relative stability in discharge peaks and timing for warning purposes. It not only gives a deterministic prediction, but also generates probability forecasts. Even though the signal was not persistent until four days before the peak discharge was observed in the 2007 flood event, the visualization based on threshold exceedance provided clear and concise essential warning information at an early stage. Forecasters could better prepare for the possibility of a flood at an early stage, and then issue an actual warning if the signal strengthened. This process may provide decision support for civil protection authorities. In future studies, different weather forecasts will be assigned various weight coefficients to represent the covariance of predictors and the extremes of distributions.

  5. Assessing Fan Flutter Stability in Presence of Inlet Distortion Using One-Way and Two-Way Coupled Methods

    NASA Technical Reports Server (NTRS)

    Herrick, Gregory P.

    2014-01-01

    Concerns regarding noise, propulsive efficiency, and fuel burn are inspiring aircraft designs wherein the propulsive turbomachines are partially (or fully) embedded within the airframe; such designs present serious concerns with regard to aerodynamic and aeromechanic performance of the compression system in response to inlet distortion. Previously, a preliminary design of a forward-swept high-speed fan exhibited flutter concerns in clean-inlet flows, and the present author then studied this fan further in the presence of off-design distorted in-flows. Continuing this research, a three-dimensional, unsteady, Navier-Stokes computational fluid dynamics code is again applied to analyze and corroborate fan performance with clean inlet flow and now with a simplified, sinusoidal distortion of total pressure at the aerodynamic interface plane. This code, already validated in its application to assess aerodynamic damping of vibrating blades at various flow conditions using a one-way coupled energy-exchange approach, is modified to include a two-way coupled timemarching aeroelastic simulation capability. The two coupling methods are compared in their evaluation of flutter stability in the presence of distorted in-flows.

  6. Multiband one-way polarization conversion in complementary split-ring resonator based structures by combining chirality and tunneling.

    PubMed

    Serebryannikov, Andriy E; Beruete, Miguel; Mutlu, Mehmet; Ozbay, Ekmel

    2015-05-18

    Multiband one-way polarization conversion and strong asymmetry in transmission inspired by it are demonstrated in ultrathin sandwiched structures that comprise two twisted aperture-type arrays of complementary split-ring resonators (CSRRs), metallic mesh, and dielectric layers. The basic features of the resulting mechanism originate from the common effect of chirality and tunneling. The emphasis is put on the (nearly) perfect polarization conversion of linear incident polarization into the orthogonal one and related diodelike asymmetric transmission within multiple narrow bands. Desired polarization conversion can be obtained at several resonances for one of the two opposite incidence directions, whereas transmission is fully blocked for the other one. The resonances, at which the (nearly) perfect conversion takes place, are expected to be inherited from similar structures with parallel, i.e., not rotated CSRR arrays that do not enable chirality and, thus, polarization conversion. It is found that the basic transmission and polarization conversion features and, thus, the dominant physics are rather general, enabling efficient engineering of such structures. The lowest-frequency resonance can be obtained in structures made of conventional materials with total thickness less than λ/50 and up to ten such resonances can correspond to thickness less than λ/20. PMID:26074599

  7. A one-way coupled atmospheric-hydrological modeling system with combination of high-resolution and ensemble precipitation forecasting

    NASA Astrophysics Data System (ADS)

    Wu, Zhiyong; Wu, Juan; Lu, Guihua

    2016-09-01

    Coupled hydrological and atmospheric modeling is an effective tool for providing advanced flood forecasting. However, the uncertainties in precipitation forecasts are still considerable. To address uncertainties, a one-way coupled atmospheric-hydrological modeling system, with a combination of high-resolution and ensemble precipitation forecasting, has been developed. It consists of three high-resolution single models and four sets of ensemble forecasts from the THORPEX Interactive Grande Global Ensemble database. The former provides higher forecasting accuracy, while the latter provides the range of forecasts. The combined precipitation forecasting was then implemented to drive the Chinese National Flood Forecasting System in the 2007 and 2008 Huai River flood hindcast analysis. The encouraging results demonstrated that the system can clearly give a set of forecasting hydrographs for a flood event and has a promising relative stability in discharge peaks and timing for warning purposes. It not only gives a deterministic prediction, but also generates probability forecasts. Even though the signal was not persistent until four days before the peak discharge was observed in the 2007 flood event, the visualization based on threshold exceedance provided clear and concise essential warning information at an early stage. Forecasters could better prepare for the possibility of a flood at an early stage, and then issue an actual warning if the signal strengthened. This process may provide decision support for civil protection authorities. In future studies, different weather forecasts will be assigned various weight coefficients to represent the covariance of predictors and the extremes of distributions.

  8. Thermal hydraulic studies of spallation target for one-way coupled Indian accelerator driven systems with low energy proton beam

    NASA Astrophysics Data System (ADS)

    Mantha, V.; Mohanty, A. K.; Satyamurthy, P.

    2007-02-01

    BARC has recently proposed a one-way coupled ADS reactor. This reactor requires typically 1 GeV proton beam with 2 mA of current. Approximately 8 kW of heat is deposited in the window of the target. Circulating liquid metal target (lead/lead-bismuth{eutectic) has to extract this heat and this is a critical R&D problem to be solved. At present there are very few accelerators, which can give few mA and high-energy proton beam. However, accelerators with low energy and hundreds of micro-ampere current are commercially available. In view of this, it is proposed in this paper to simulate beam window heating of 8 kW in the target with low-energy proton beam. Detailed thermal analysis in the spallation and window region has been carried out to study the capability of heat extraction by circulating LBE for a typical target loop with a proton beam of 30 MeV energy and current of 0.267 mA. The heat deposition study is carried out using FLUKA code and flow analysis by CFD code. The detailed analysis of this work is presented in this paper.

  9. Challenging the One-Way Paradigm for More Effective Science Communication: A Critical Review of Two Public Campaigns Addressing Contentious Environmental Issues

    ERIC Educational Resources Information Center

    McEntee, Marie; Mortimer, Claire

    2013-01-01

    This article examines two large-scale public communication campaigns to explore the appropriateness and effectiveness of using one-way communication in contentious environmental issues. The findings show while one-way communication can be successfully employed in contentious issues, it is not appropriate for all contexts and may contribute to…

  10. 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)

  11. Two-way against one-way nesting for climate downscaling in Europe and the Mediterranean region using LMDZ4

    NASA Astrophysics Data System (ADS)

    Li, Shan; Li, Laurent; Le Treut, Hervé

    2016-04-01

    In the 21st century, the estimated surface temperature warming projected by General Circulation Models (GCMs) is between 0.3 and 4.8 °C, depending on the scenario considered. GCMs exhibit a good representation of climate on a global scale, but they are not able to reproduce regional climate processes with the same level of accuracy. Society and policymakers need model projections to define climate change adaptation and mitigation policies on a global, regional and local scale. Climate downscaling is mostly conducted with a regional model nested into the outputs of a global model. This one-way nesting approach is generally used in the climate community without feedbacks from Regional Climate Models (RCMs) to GCMs. This lack of interaction between the two models may affect regional modes of variability, in particular those with a boundary conflict. The objective of this study is to evaluate a two-way nesting configuration that makes an interactive coupling between the RCM and the GCM, an approach against the traditional configuration of one-way nesting system. An additional aim of this work is to examine if the two-way nesting system can improve the RCM performance. The atmospheric component of the IPSL integrated climate model (LMDZ) is configured at both regional (LMDZ-regional) and global (LMDZ-global) scales. The two models have the same configuration for the dynamical framework and the physical forcings. The climatology values of sea surface temperature (SST) are prescribed for the two models. The stretched-grid of LMDZ-global is applied to a region defined by Europe, the Mediterranean, North Africa and Western North Atlantic. To ensure a good statistical significance of results, all simulations last at least 80 years. The nesting process of models is performed by a relaxation procedure of a time scale of 90 minutes. In the case of two-way nesting, the exchange between the two models is every two hours. The relaxation procedure induces a boundary conflict

  12. Mitral Valve Prolapse

    MedlinePlus

    ... Long Q-T Syndrome Marfan Syndrome Metabolic Syndrome Mitral Valve Prolapse Myocardial Bridge Myocarditis Obstructive Sleep Apnea Pericarditis ... Stroke Sudden Cardiac Arrest Valve Disease Vulnerable Plaque Mitral Valve Prolapse | Share Related terms: MVP, disease of the ...

  13. 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 ...

  14. 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.

  15. Aortic Valve Disease

    MedlinePlus

    ... Disease Tricuspid Valve Disease Cardiac Rhythm Disturbances Thoracic Aortic Aneurysm Pediatric and Congenital Heart Disease Heart abnormalities that ... Disease Tricuspid Valve Disease Cardiac Rhythm Disturbances Thoracic Aortic Aneurysm Aortic Valve Disease Overview The human heart has ...

  16. Mitral Valve Prolapse

    MedlinePlus

    ... Problem: Pulmonary Valve Regurgitation Heart Valves and Infective Endocarditis • Risks, Signs and Symptoms • Accurate Diagnosis • Treatment Options • ... Surgery? Recovery Milestones Checklist | Spanish What Is Infective Endocarditis? | Spanish Interactive Treatment Guide Quiz yourself: Heart Valves ...

  17. Is there more than one way to skin a newt? Convergent toxin resistance in snakes is not due to a common genetic mechanism.

    PubMed

    Feldman, C R; Durso, A M; Hanifin, C T; Pfrender, M E; Ducey, P K; Stokes, A N; Barnett, K E; Brodie, E D; Brodie, E D

    2016-01-01

    Convergent evolution of tetrodotoxin (TTX) resistance, at both the phenotypic and genetic levels, characterizes coevolutionary arms races between amphibians and their snake predators around the world, and reveals remarkable predictability in the process of adaptation. Here we examine the repeatability of the evolution of TTX resistance in an undescribed predator-prey relationship between TTX-bearing Eastern Newts (Notophthalmus viridescens) and Eastern Hog-nosed Snakes (Heterodon platirhinos). We found that that local newts contain levels of TTX dangerous enough to dissuade most predators, and that Eastern Hog-nosed Snakes within newt range are highly resistant to TTX. In fact, these populations of Eastern Hog-nosed Snakes are so resistant to TTX that the potential for current reciprocal selection might be limited. Unlike all other cases of TTX resistance in vertebrates, H. platirhinos lacks the adaptive amino acid substitutions in the skeletal muscle sodium channel that reduce TTX binding, suggesting that physiological resistance in Eastern Hog-nosed Snakes is conferred by an alternate genetic mechanism. Thus, phenotypic convergence in this case is not due to parallel molecular evolution, indicating that there may be more than one way for this adaptation to arise, even among closely related species. PMID:26374236

  18. 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.

  19. Pulmonary valve stenosis

    MedlinePlus

    ... valve pulmonary stenosis; Pulmonary stenosis; Stenosis - pulmonary valve; Balloon valvuloplasty - pulmonary ... water pills) Treat abnormal heartbeats and rhythms Percutaneous balloon pulmonary dilation (valvuloplasty) may be performed when no ...

  20. 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.

  1. [Mitral valve replacement for congenital parachute mitral valve].

    PubMed

    Sasahashi, N; Ando, F; Okamoto, F; Yamanaka, K; Hanada, T; Makino, S

    1995-07-01

    A one-year-old boy was admitted with refractory congestive biventricular heart failure for medical treatment. On echocardiogram and cardiac catheterization revealed severe mitral stenosis from parachute deformity with pulmonary hypertension. During the operation, a single round orifice of 7 mm in diameter was detected in the mitral valve and adhered chordae were attached to a large single papillary muscle which was located at the posteromedial portion of the left ventricle. An isolated muscle band which was not attached to the mitral valve was observed at the anterolateral wall of the left ventricle. The mitral valve was replaced with 16 mm Carbo-Medicus prosthesis. Postoperative catheterization revealed residual pulmonary hypertension which was responsive to Imidarine infusion. He was discharged from the hospital without any sequelae, and has been on regimen including anticoaglant and vasodilator. PMID:7561327

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

    PubMed

    Woerdeman, Peter A; Cochrane, David D

    2014-05-01

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

  3. Pressure relief valve/safety relief valve testing

    SciTech Connect

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

    1994-02-01

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

  4. 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.

  5. Microfluidic sieve valves

    SciTech Connect

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

    2015-01-13

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

  6. Remote actuated valve implant

    DOEpatents

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

    2016-05-10

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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Vacuum breaker valve assembly

    DOEpatents

    Thompson, J.L.; Upton, H.A.

    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. 1 fig.

  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. 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.

  14. Valve for fluid control

    DOEpatents

    Oborny, Michael C.; Paul, Phillip H.; Hencken, Kenneth R.; Frye-Mason, Gregory C.; Manginell, Ronald P.

    2001-01-01

    A valve for controlling fluid flows. This valve, which includes both an actuation device and a valve body provides: the ability to incorporate both the actuation device and valve into a unitary structure that can be placed onto a microchip, the ability to generate higher actuation pressures and thus control higher fluid pressures than conventional microvalves, and a device that draws only microwatts of power. An electrokinetic pump that converts electric potential to hydraulic force is used to operate, or actuate, the valve.

  15. Arachnoid cyst slit valves: the mechanism for arachnoid cyst enlargement.

    PubMed

    Halani, Sameer H; Safain, Mina G; Heilman, Carl B

    2013-07-01

    Arachnoid cysts are common, accounting for approximately 1% of intracranial mass lesions. Most are congenital, clinically silent, and remain static in size. Occasionally, they increase in size and produce symptoms due to mass effect or obstruction. The mechanism of enlargement of arachnoid cysts is controversial. One-way slit valves are often hypothesized as the mechanism for enlargement. The authors present 4 cases of suprasellar prepontine arachnoid cysts in which a slit valve was identified. The patients presented with hydrocephalus due to enlargement of the cyst. The valve was located in the arachnoid wall of the cyst directly over the basilar artery. The authors believe this slit valve was responsible for the net influx of CSF into the cyst and for its enlargement. They also present 1 case of an arachnoid cyst in the middle cranial fossa that had a small circular opening but lacked a slit valve. This cyst did not enlarge but surgery was required because of rupture and the development of a subdural hygroma. One-way slit valves exist and are a possible mechanism of enlargement of suprasellar prepontine arachnoid cysts. The valve was located directly over the basilar artery in each of these cases. Caudad-to-cephalad CSF flow during the cardiac cycle increased the opening of the valve, whereas cephalad-to-caudad CSF flow during the remainder of the cardiac cycle pushed the slit opening against the basilar artery and decreased the size of the opening. Arachnoid cysts that communicate CSF via circular, nonslit valves are probably more likely to remain stable. PMID:23662935

  16. [Early bioprosthetic mitral valve thrombosis].

    PubMed

    Tkaczyszyn, Michał; Olbrycht, Tomasz; Kustrzycka Kratochwil, Dorota; Sokolski, Mateusz; Sukiennik Kujawa, Małgorzata; Skiba, Jacek; Gemel, Marek; Banasiak, Waldemar; Jankowska, Ewa A; Ponikowski, Piotr

    2012-01-01

    We present a case of a 70 year-old woman operated due to severe mitral regurgitation. Early after surgery transthoracic echocardiography revealed the decreased effective orifice area of the implanted bioprosthetic valve and the stenotic features of transvalvular flow. Transesophageal echocardiography (TEE) disclosed a thrombotic cause of heterograft dysfunction. Due to the clinical deterioration and the unclear cause of prosthesis stenosis, the patient was reoperated. Intra-operatively bioprosthetic mitral valve thrombosis was confirmed. Precipitating factors of this rare complication including cardiac device related infective endocarditis (CDRIE) and the diagnostic applicability of TEE in this clinical scenario are discussed. PMID:22427084

  17. One-way return-link Doppler navigation with the Tracking and Data Satellite System (TDRSS) - The ultrastable oscillator (USO) experiment on the Cosmic Background Explorer (COBE)

    NASA Technical Reports Server (NTRS)

    Dunham, J. B.; Nemesure, M.; Teles, J.; Brown-Conwell, E. R.; Jackson, J. A.; Reamy, V. L.; Maher, M. J.; Elrod, B. D.

    1990-01-01

    The principal objectives of the USO experiment on the COBE spacecraft are defined, and results of space qualification studies for the COBE USO experiment are summarized. The principal objectives of the experiment are: (1) to determine flight performance of the USO coupled to the second-generation TDRSS transponder; (2) space qualify TDRSS noncoherent one-way return-link Doppler tracking; and (3) analyze algorithms for one-way navigation with real data. The three objectives of the experiment have been met in the first stage of the experiment analysis.

  18. Spring and valve skirt

    SciTech Connect

    Moore, L.

    1986-07-29

    This patent describes an engine having a valve guide operatively mounting a valve stem and its associated valve spring and spring retainer for actuation of the valve stem by a valve actuator. An improvement is described comprising: a hollow, generally cylindrical shaped skirt means having a side portion forming an interior with one open end and having at its other end an end portion extending inwardly and formed with an axial opening therein communicating to the interior. The skirt means is mounted on and about the valve stem and spring retainer and about its spring so as to move with the valve stem and to cover the spring retainer and most of the portion of the valve spring and the valve stem extending outwardly from the valve guide except for an outermost end of the stem which extends through the opening in the end portion for actuation by the actuator , such that the inwardly extending end portion lies between the outermost end of the stem and an outermost end of the spring retainer to allow for retrofitting insertion of the skirt means over existing valve stems without removal of the spring and spring retainer. Excessive oil is presented from seeping between and valve guide and the valve stem thus preventing excessive carbon build-up in the combustion area, sticking valves, fouled plugs and high exhaust emissions.

  19. Delayed migration of Sapien valve following a transcatheter mitral valve-in-valve implantation.

    PubMed

    Bapat, Vinayak Vinnie Nilkanth; Khaliel, Feras; Ihleberg, Leo

    2014-01-01

    We report two cases of delayed migration of the Sapien XT device after a successful mitral valve-in-valve (VIV) implantation. The procedure was performed through a transapical approach. Echocardiography was used to choose the size of the Sapien XT device. Although the immediate results were satisfactory both the cases presented with severe regurgitation (1 week and 3 months). Investigations revealed atrial migration of the Sapien device in both the cases, which was confirmed at the time of reoperation. We discuss possible mechanisms, which could have resulted in the delayed migration and highlight the difference between VIV procedures in mitral position versus other positions. PMID:23784983

  20. 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.

  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. 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.

  3. Transcatheter aortic valve implantation

    PubMed Central

    Oliemy, Ahmed

    2014-01-01

    Transcatheter aortic valve implantation was developed to offer a therapeutic solution to patients with severe symptomatic aortic stenosis who are not candidates for conventional aortic valve replacement. The improvement in transcatheter aortic valve implantation outcomes is still of concern in the areas of stroke, vascular injury, heart block, paravalvular regurgitation and valve durability. Concomitantly, the progress, both technical and in terms of material advances of transcatheter valve systems, as well as in patient selection, renders transcatheter aortic valve implantation an increasingly viable treatment for more and more patients with structural heart disease. PMID:25374670

  4. Distance Education: One Way Television with Simultaneous Telephone Group Conferencing Using Satellite Maps as a Monitoring Device. A Report to the Innovative Projects Fund.

    ERIC Educational Resources Information Center

    Kirman, Joseph M.; Goldberg, Jack

    This study compared teachers instructed in use of Landsat satellite maps through one-way television and simultaneous telephone group conferencing to another teacher group instructed directly. Thirty teachers of intermediate children in Edmonton and Sherwood Park, Alberta, received 5 hours of instruction about Landsat maps over a 2-week period;…

  5. Rare Case of Unileaflet Mitral Valve

    PubMed Central

    Jain, Tarun; Shah, Sunay; Mawri, Sagger; Ananthasubramaniam, Karthikeyan

    2016-01-01

    Unileaflet mitral valve is the rarest of the congenital mitral valve anomalies and is usually life threatening in infancy due to severe mitral regurgitation (MR). In most asymptomatic individuals, it is mostly due to hypoplastic posterior mitral leaflet. We present a 22-year-old male with palpitations, who was found to have an echocardiogram revealing an elongated anterior mitral valve leaflet with severely hypoplastic posterior mitral valve leaflet appearing as a unileaflet mitral valve without MR. Our case is one of the 11 reported cases in the literature so far. We hereby review those cases and conclude that these patients are likely to be at risk of developing worsening MR later in their lives. PMID:27358711

  6. Aortic valve repair for papillary fibroelastoma.

    PubMed

    Di Marco, Luca; Al-Basheer, Amin; Glineur, David; Oppido, Guido; Di Bartolomeo, Roberto; El-Khoury, Gebrine

    2006-05-01

    We report the case of aortic valve-papillary fibroelastoma in a 66-year-old Belgian woman with a previous single episode of cerebral transient ischemic attack. Transthoracic two-dimensional echocardiography revealed a small mass adherent to the noncoronary cusp of the valve, which was confirmed by transesophageal echocardiography. Indication for surgery was performed because of a previous cerebral transient ischemic attack and for its potential risk of cerebral and coronary embolization. Surgical excision of the mass was performed with the need for glutaraldehyde-treated autologous pericardial patch repair of the aortic cusp. Intraoperative and postoperative transesophageal echocardiography both showed the valve to be competent. Postoperative recovery was uneventful. After a review of the literature, we conclude that, even if asymptomatic, and independent of their size, aortic valve papillary fibroelastomas justify surgical excision for their potential to systemic embolization. Moreover, we believe that a valve-sparing approach might be feasible with no recurrence after complete excision. PMID:16645416

  7. Heart valve surgery - series (image)

    MedlinePlus

    ... heart valves are either natural (biologic) or artificial (mechanical). Natural valves are from human donors (cadavers), modified ... artificial valves will require anticoagulation. The advantage of mechanical valves is that they last longer-thus, the ...

  8. Modeling ocean response to an extreme Bora event in Northern Adriatic using one-way and two-way atmosphere-ocean coupling

    NASA Astrophysics Data System (ADS)

    Ličer, M.; Smerkol, P.; Fettich, A.; Ravdas, M.; Papapostolou, A.; Mantziafou, A.; Strajnar, B.; Cedilnik, J.; Jeromel, M.; Jerman, J.; Petan, S.; Malačič, V.; Sofianos, S.

    2015-07-01

    We study the performances of (a) fully two-way coupled atmosphere-ocean modeling system and (b) one-way coupled ocean model (forced by the atmospheric model hourly output), as compared to the available in situ (mooring and CTD) measurements during and after an strong Bora wind event in February 2012, which led to extreme air-sea interactions and record breaking seawater cooling and dense water formation in Northern Adriatic. The simulations span the period between January and March 2012. The models used were ALADIN (4.4 km resolution) on the atmospheric side and Adriatic setup of POM (1°/30 × 1°/30 angular resolution) on the ocean side. The atmosphere-ocean coupling was implemented using the OASIS3-MCT model coupling toolkit. We show, using in situ seawater temperature measurements, that the two-way atmosphere-ocean coupling improves the ocean response to Bora because it captures transient Bora-induced cooling better than the one-way coupled version of the ocean model. We show that this difference stems mainly from an underestimation of air-sea temperature difference in one-way coupled system during the Bora episode, leading to an underestimation of sensible heat losses from the ocean in the one-way coupled system. We show these losses exhibit significant impact on baroclinic circulation on synoptic timescales. We use CTD observations in the Gulf of Trieste to show that when compared to the one-way setup, the two-way coupled system produces a similar estimation of salinities and density anomalies before the Bora episode, but a significantly better estimation of these quantities afterwards.

  9. Mitral valve disease—morphology and mechanisms

    PubMed Central

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

    2016-01-01

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

  10. Mitral valve disease--morphology and mechanisms.

    PubMed

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

    2015-12-01

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

  11. Aortic valve surgery - open

    MedlinePlus

    ... There are two main types of new valves: Mechanical, made of man-made materials, such as titanium ... Mechanical heart valves do not fail often. However, blood clots can develop on them. If a blood ...

  12. Mitral valve surgery - open

    MedlinePlus

    ... place. There are two types of mitral valves: Mechanical, made of man-made (synthetic) materials, such as ... Mechanical heart valves do not fail often. They last from 12 to 20 years. However, blood clots ...

  13. Mitral Valve Disease

    MedlinePlus

    ... disease occurs when the mitral valve doesn’t work properly. Types of Mitral Valve Disease Types of ... until you are able to go back to work, depending on your job. Everyday activities such as ...

  14. Mitral valve surgery - open

    MedlinePlus

    ... the rest of your life. Biological, made of human or animal tissue. These valves last 10 to 12 years. ... occur, but this is rare. Valves made from human or animal tissue fail over time, but have a lower ...

  15. Absent pulmonary valve

    MedlinePlus

    ... can occur with absent pulmonary valve include: Abnormal tricuspid valve Atrial septal defect Double outlet right ventricle Ductus arteriosis Endocardial cushion defect Marfan syndrome Tricuspid atresia Heart problems that occur with absent pulmonary ...

  16. Valve Health Monitor (VHM)

    NASA Technical Reports Server (NTRS)

    Perotti, Jose M.; Delgado, H. (Technical Monitor)

    2002-01-01

    This presentation reports on progress being made on developing a Valve Health Monitor (VHM) Smart Current Signature Sensor. Topics cover include: design needs, target valves, current signatures, VHM design approach and VHM status/conclusions.

  17. 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.

  18. Absent pulmonary valve

    MedlinePlus

    ... absent pulmonary valve syndrome associated with bronchial obstruction. Ann Thoracic Surg. 2006;82:2221-2226. PMID: 17126138 ... of airway compression in absent pulmonary valve syndrome. Ann Thorac Surg . 2006;81:1802-1807. PMID: 16631676 ...

  19. 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.

  20. 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.

  1. 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.

  2. Overflow control valve

    DOEpatents

    Hundal, Rolv; Kessinger, Boyd A.; Parlak, Edward A.

    1984-07-24

    An overflow control valve for use in a liquid sodium coolant pump tank which valve can be extended to create a seal with the pump tank wall or retracted to break the seal thereby accommodating valve removal. An actuating shaft which controls valve disc position also has cams which bear on roller surfaces to force retraction of a sliding cylinder against spring tension to retract the cylinder from sealing contact with the pump tank.

  3. Burst diaphragm sequence valve

    NASA Astrophysics Data System (ADS)

    Wisneskie, Bradley D.; Hyman, Sheldon; Hallum, Charles E.

    1991-11-01

    A burst diaphragm sequence valve which effectively combines the structure of a burst diaphragm with that of an ordinary swing check valve, the pivot of the ordinary swing check valve being replaced by an integral flexural hinge. The sequence valve provides a way to sequentially burn solid propellant hot gas generators which exit into a common gas manifold, thereby enabling gas-powered devices to operate for a longer time than the duration of one gas generator burn.

  4. 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.

  5. 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 ...

  6. Fuel distribution valve

    SciTech Connect

    Halvorsen, R.M.; Hurst, J.B.

    1986-09-30

    This patent describes a fuel flow distribution valve for dividing and metering fuel flow from a fuel source to nozzles for supplying fuel to an engine comprising valve body means having an inlet and outlets, intermediate liner means forming a longitudinal valve bore in the valve body means. The intermediate liner means has a reference surface thereon, a valve slidably supported in the valve bore slidable longitudinally therein and having a close tolerance diametral fit therewith. The valve has a positioning surface engageable with the reference surface and movable to a spaced apart position therefrom, spring means for biasing the valve in a first direction with respect to the liner means to engage the positioning surface and reference surface. The valve also has a means for directing inlet pressure against the valve in opposition to the spring means, pairs of in line-machined flow metering ports in the liner means and value with the ports in each pair being congruent by virtue of being machined simultaneously with a common tool in the liner means and the valve when the valve is in a fixed position in the bore with the positioning surface spaced a preselected longitudinal distance from the reference surface to define spaced pairs of congruent flow metering ports.

  7. 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.

  8. 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.

  9. 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.

  10. Thermally actuated valve

    NASA Technical Reports Server (NTRS)

    Silver, R. H.

    1973-01-01

    Effective seal in one-shot valve is made by shrink-fitting ball within cylinder; thermal expansion of cylinder, caused by contiguous source of heat, will release ball and open valve. Valve can also be adapted for repeated operation and made capable of being opened without pressurized fluid.

  11. Compact valve actuation mechanism

    NASA Technical Reports Server (NTRS)

    Brogdon, James William (Inventor); Gill, David Keith (Inventor)

    2000-01-01

    A valve actuation device. The device may include a free floating valve bridge movably supported within a cavity in the engine housing. The bridge may be provided with a cavity and an orifice arrangement for pumping gases entrained with lubricating fluid toward the piston stems as the bridge reciprocates back and forth. The device may also include a rocker arm that has a U-shaped cross-sectional shape for receiving at least a portion of the valve bridge, valve stem valve spring and spring retainer therein. The rocker arm may be provided with lubrication passages for directing lubrication to the point wherein it is pivotally affixed to the engine housing.

  12. Minimally Invasive Valve Surgery

    PubMed Central

    Pope, Nicolas H.; Ailawadi, Gorav

    2014-01-01

    Cardiac valve surgery is life saving for many patients. The advent of minimally invasive surgical techniques has historically allowed for improvement in both post-operative convalescence and important clinical outcomes. The development of minimally invasive cardiac valve repair and replacement surgery over the past decade is poised to revolutionize the care of cardiac valve patients. Here, we present a review of the history and current trends in minimally invasive aortic and mitral valve repair and replacement, including the development of sutureless bioprosthetic valves. PMID:24797148

  13. Challenges in valve-in-valve therapy.

    PubMed

    Noorani, Alia; Radia, Rahee; Bapat, Vinayak

    2015-09-01

    At present, the majority of surgical heart valves (SHVs) implanted are bioprosthetic valves. Over time however, these are prone to structural deterioration, which may manifest as valvular stenosis, regurgitation or a combination of the two. Re-operation is the current standard of care for these patients but this itself carries a significant risk of mortality and morbidity. As a natural extension of transcatheter aortic valve implantation (TAVI), now an evidence based solution for severe aortic stenosis in high-risk patients, valve-in-valve (VIV) therapy is evolving into an alternative option in selected patients with structural biological valvular deterioration in all four-valve positions. The first of these VIV procedures was performed in Germany in 2007, for failing aortic valve prosthesis and later, reported in other positions. As with any novel emerging therapy, there is a learning curve to the procedure and the operator must be aware of the potential challenges. In this review we describe some of these challenges with the aim of providing awareness as well as guidance on attaining a successful outcome. PMID:26543595

  14. Challenges in valve-in-valve therapy

    PubMed Central

    Noorani, Alia; Radia, Rahee

    2015-01-01

    At present, the majority of surgical heart valves (SHVs) implanted are bioprosthetic valves. Over time however, these are prone to structural deterioration, which may manifest as valvular stenosis, regurgitation or a combination of the two. Re-operation is the current standard of care for these patients but this itself carries a significant risk of mortality and morbidity. As a natural extension of transcatheter aortic valve implantation (TAVI), now an evidence based solution for severe aortic stenosis in high-risk patients, valve-in-valve (VIV) therapy is evolving into an alternative option in selected patients with structural biological valvular deterioration in all four-valve positions. The first of these VIV procedures was performed in Germany in 2007, for failing aortic valve prosthesis and later, reported in other positions. As with any novel emerging therapy, there is a learning curve to the procedure and the operator must be aware of the potential challenges. In this review we describe some of these challenges with the aim of providing awareness as well as guidance on attaining a successful outcome. PMID:26543595

  15. 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.

  16. Fungal Prosthetic Valve Endocarditis by Candida parapsilosis: A Case Report

    PubMed Central

    Shokohi, Tahereh; Nouraei, Seyed Mahmood; Afsarian, Mohammad Hosein; Najafi, Narges; Mehdipour, Shirin

    2014-01-01

    Introduction: Fungal prosthetic valve endocarditis (PVE) is rare but serious complication of valve replacement surgery. Candida species, particularly Candida albicans is the most common isolated pathogen in fungal PVE (1–6%of cases). Case Presentation: We describe a 35-year-old woman who underwent mechanical mitral valve replacement about 3 years ago. She was admitted with neurological symptoms and later with dyspnea and hypotension. Transesophageal echocardiography showed large and mobile prosthetic valve vegetation. She underwent mitral valve surgery. The explanted valve and vegetation revealed lots of budding yeasts and the isolated yeast was identified as C. parapsilosis. Amphotericin B and broad spectrum antibiotic were started immediately. Unfortunately, the patient died two days after surgery, due to sepsis probably related to the candidemia. Conclusions: Fungal endocarditis is uncommon infection, but it is a serious problem in patients with prosthetic valve. Fungal PVE can occur years after the surgery, thus long-term follow-up is essential. PMID:25147692

  17. A molecular-sized tunnel-porous crystal with a ratchet gear structure and its one-way guest-molecule transportation property

    NASA Astrophysics Data System (ADS)

    Kataoka, Keisuke; Yasumoto, Tetsuaki; Manabe, Yousuke; Sato, Hiroyasu; Yamano, Akihito; Katagiri, Toshimasa

    2013-01-01

    An anisotropic tunnel microporous crystal was prepared. Active transportation of anthracene as a guest molecule in the anisotropic tunnels was observed. The direction of anthracene movement implies that the anisotropic tunnel did not work as a flap-check valve. The direction of the movement was consistent with that caused by a Brownian ratchet.An anisotropic tunnel microporous crystal was prepared. Active transportation of anthracene as a guest molecule in the anisotropic tunnels was observed. The direction of anthracene movement implies that the anisotropic tunnel did not work as a flap-check valve. The direction of the movement was consistent with that caused by a Brownian ratchet. Electronic supplementary information (ESI) available. CCDC reference numbers 837539 and 837540. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c2nr30880k

  18. 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.

  19. Transluminal aortic valve placement. A feasibility study with a newly designed collapsible aortic valve.

    PubMed

    Moazami, N; Bessler, M; Argenziano, M; Choudhri, A F; Cabreriza, S E; Allendorf, J D; Rose, E A; Oz, M C

    1996-01-01

    Percutaneous stents are used in vascular applications in conjunction with angioplasty and in combination with graft material for repair of abdominal aneurysms. The authors have designed a collapsible bioprosthetic aortic valve for placement by a transluminal catheter technique. This trileaflet stent valve is composed of stainless steel and bovine pericardium. Stent valves, 23 and 29 mm, were tested in a pulse duplicator system with rigid rings from 21 to 31 mm in 2 mm increments. At a mean flow of 3.1 L/min (+/-0.7), normal systemic aortic pressure was generated with a transvalvular gradient of 14.9 +/- 7 mmHg (mean +/- SD). Regurgitation fraction ranged from 10 to 18% (mean 13.8 +/- 3%) in the best ring size. Valves with the best hemodynamic profile were used for implantation in three 70 kg pigs in an open chest model. The valve was collapsed in a 24 Fr catheter designed to allow slow, controlled release. After resection of the native leaflets, the new valve was placed in the subcoronary position. No additional sutures were used for securing the valve. Two animals were successfully weaned from cardiopulmonary bypass and maintained systemic pressures of 100/45 (+/-10) and 116/70 (+/-15) mmHg, respectively. Intraoperative color echocardiography revealed minimal regurgitation, central flow, full apposition of all leaflets, and no interference with coronary blood flow. Both animals were sacrificed after being off bypass for 2 hr. Postmortem examination revealed the valves to be securely anchored. The third animal was weaned from cardiopulmonary bypass but developed refractory ventricular fibrillation because of valve dislodgment due to structural failure. Although long term survival data are needed, development of a hemodynamically acceptable prosthetic aortic valve for transluminal placement is feasible. PMID:8944912

  20. 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.

  1. Force Augmentation for Relief Valve

    NASA Technical Reports Server (NTRS)

    Luger, J.

    1982-01-01

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

  2. 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.

  3. 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. PMID:22995119

  4. Dual valve plate two-way pressure relief valve

    NASA Astrophysics Data System (ADS)

    Angeli, Robert J.

    1994-02-01

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

  5. Nanobacteria-associated calcific aortic valve stenosis.

    PubMed

    Jelic, Tomislav M; Chang, Ho-Huang; Roque, Rod; Malas, Amer M; Warren, Stafford G; Sommer, Andrei P

    2007-01-01

    Calcific aortic valve stenosis is the most common valvular disease in developed countries, and the major reason for operative valve replacement. In the US, the current annual cost of this surgery is approximately 1 billion dollars. Despite increasing morbidity and mortality, little is known of the cellular basis of the calcifications, which occur in high-perfusion zones of the heart. The case is presented of a patient with calcific aortic valve stenosis and colonies of progressively mineralized nanobacteria in the fibrocalcific nodules of the aortic cusps, as revealed by transmission electron microscopy. Consistent with their outstanding bioadhesivity, nanobacteria might serve as causative agents in the development of calcific aortic valve stenosis. PMID:17315391

  6. 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.

  7. [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. PMID:26907868

  8. Development of myoelectric control type speaking valve with low flow resistance

    NASA Astrophysics Data System (ADS)

    Ooe, Katsutoshi; Sakurai, Kohei; Mimaki, Shinya

    2015-12-01

    We aimed to develop welfare devices for patients with phonation disorder. One of these devices is the electrical controltype speaking valve system. The conventional speaking valves have one-way valve architecture, they open when the user breathes in, and they close when user breathes out and produce voices. This type is very simple and tough, but some users feel closeness in case of exhalation without phonation. This problem is caused by its mechanism what can not be controlled by user's will. Therefore, we proposed an electrical control-type speaking valve system to resolve this problem. This valve is controlled by neck myoelectric signal of sternohyoid muscle. From our previous report, it was clarified that this valve had better performance about easy-to-breath. Furthermore, we proposed the compact myoelectric control-type speaking valve system. The new-type speaking valve was enough small to attach the human body, and its opening area is larger than that of conventional one. Additionally, we described the improvement of flow channel shape by using of FEM analysis. According to the result of the analysis, it was clarified that the shape-improved speaking valve gets the low flow resistance channel in case of inspiration. In this report, we tried to make the flow resistance lower by the shape of current plates, in case of both inspiration and exhalation. From the result of FEM analysis, our speaking valve could get better flow channel than older one.

  9. Improved One-Way Hash Chain and Revocation Polynomial-Based Self-Healing Group Key Distribution Schemes in Resource-Constrained Wireless Networks

    PubMed Central

    Chen, Huifang; Xie, Lei

    2014-01-01

    Self-healing group key distribution (SGKD) aims to deal with the key distribution problem over an unreliable wireless network. In this paper, we investigate the SGKD issue in resource-constrained wireless networks. We propose two improved SGKD schemes using the one-way hash chain (OHC) and the revocation polynomial (RP), the OHC&RP-SGKD schemes. In the proposed OHC&RP-SGKD schemes, by introducing the unique session identifier and binding the joining time with the capability of recovering previous session keys, the problem of the collusion attack between revoked users and new joined users in existing hash chain-based SGKD schemes is resolved. Moreover, novel methods for utilizing the one-way hash chain and constructing the personal secret, the revocation polynomial and the key updating broadcast packet are presented. Hence, the proposed OHC&RP-SGKD schemes eliminate the limitation of the maximum allowed number of revoked users on the maximum allowed number of sessions, increase the maximum allowed number of revoked/colluding users, and reduce the redundancy in the key updating broadcast packet. Performance analysis and simulation results show that the proposed OHC&RP-SGKD schemes are practical for resource-constrained wireless networks in bad environments, where a strong collusion attack resistance is required and many users could be revoked. PMID:25529204

  10. 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.

  11. 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.

  12. 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

  13. DISCONTINUED OR LITTLE USED LARGE GATE VALVE AND VALVE ASSEMBLY ...

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

    DISCONTINUED OR LITTLE USED LARGE GATE VALVE AND VALVE ASSEMBLY PATTERNS, PATTERN STORAGE BUILDING. - Stockham Pipe & Fittings Company, Pattern Storage, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  14. Medications for Heart Valve Symptoms

    MedlinePlus

    ... Pressure Tools & Resources Stroke More Medications for Heart Valve Symptoms Updated:Aug 26,2015 How do medications ... was last reviewed on 03/26/14. Heart Valves Problems and Disease • Home • About Heart Valves • Heart ...

  15. Modeling the ocean and atmosphere during an extreme bora event in northern Adriatic using one-way and two-way atmosphere-ocean coupling

    NASA Astrophysics Data System (ADS)

    Ličer, M.; Smerkol, P.; Fettich, A.; Ravdas, M.; Papapostolou, A.; Mantziafou, A.; Strajnar, B.; Cedilnik, J.; Jeromel, M.; Jerman, J.; Petan, S.; Malačič, V.; Sofianos, S.

    2016-01-01

    We have studied the performances of (a) a two-way coupled atmosphere-ocean modeling system and (b) one-way coupled ocean model (forced by the atmosphere model), as compared to the available in situ measurements during and after a strong Adriatic bora wind event in February 2012, which led to extreme air-sea interactions. The simulations span the period between January and March 2012. The models used were ALADIN (Aire Limitée Adaptation dynamique Développement InterNational) (4.4 km resolution) on the atmosphere side and an Adriatic setup of Princeton ocean model (POM) (1°/30 × 1°/30 angular resolution) on the ocean side. The atmosphere-ocean coupling was implemented using the OASIS3-MCT model coupling toolkit. Two-way coupling ocean feedback to the atmosphere is limited to sea surface temperature. We have compared modeled atmosphere-ocean fluxes and sea temperatures from both setups to platform and CTD (conductivity, temperature, and depth) measurements from three locations in the northern Adriatic. We present objective verification of 2 m atmosphere temperature forecasts using mean bias and standard deviation of errors scores from 23 meteorological stations in the eastern part of Italy. We show that turbulent fluxes from both setups differ up to 20 % during the bora but not significantly before and after the event. When compared to observations, two-way coupling ocean temperatures exhibit a 4 times lower root mean square error (RMSE) than those from one-way coupled system. Two-way coupling improves sensible heat fluxes at all stations but does not improve latent heat loss. The spatial average of the two-way coupled atmosphere component is up to 0.3 °C colder than the one-way coupled setup, which is an improvement for prognostic lead times up to 20 h. Daily spatial average of the standard deviation of air temperature errors shows 0.15 °C improvement in the case of coupled system compared to the uncoupled. Coupled and uncoupled circulations in the northern

  16. Non-plugging injection valve

    DOEpatents

    Carey, Jr., Henry S.

    1985-01-01

    A valve for injecting fluid into a conduit carrying a slurry subject to separation to form deposits capable of plugging openings into the conduit. The valve comprises a valve body that is sealed to the conduit about an aperture formed through the wall of the conduit to receive the fluid to be injected and the valve member of the valve includes a punch portion that extends through the injection aperture to the flow passage, when the valve is closed, to provide a clear channel into the conduit, when the valve is opened, through deposits which might have formed on portions of the valve adjacent the conduit.

  17. 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 ...

  18. Static Flow Characteristics of a Mass Flow Injecting Valve

    NASA Technical Reports Server (NTRS)

    Mattern, Duane; Paxson, Dan

    1995-01-01

    A sleeve valve is under development for ground-based forced response testing of air compression systems. This valve will be used to inject air and to impart momentum to the flow inside the first stage of a multi-stage compressor. The valve was designed to deliver a maximum mass flow of 0.22 lbm/s (0.1 kg/s) with a maximum valve throat area of 0.12 sq. in (80 sq. mm), a 100 psid (689 KPA) pressure difference across the valve and a 68 F, (20 C) air supply. It was assumed that the valve mass flow rate would be proportional to the valve orifice area. A static flow calibration revealed a nonlinear valve orifice area to mass flow relationship which limits the maximum flow rate that the valve can deliver. This nonlinearity was found to be caused by multiple choking points in the flow path. A simple model was used to explain this nonlinearity and the model was compared to the static flow calibration data. Only steady flow data is presented here. In this report, the static flow characteristics of a proportionally controlled sleeve valve are modelled and validated against experimental data.

  19. A Rare Case of Mitral Valve Prolapse in Endomyocardial Fibrosis.

    PubMed

    Xavier, Joseph; Haranal, Maruti Yamanappa; Reddy, Shashidhar Ranga; Suryaprakash, Sharadaprasad

    2016-09-01

    Mitral valve prolapse in endomyocardial fibrosis (EMF) is an unusual entity. Literature search reveals only 1 report of mitral valve prolapse assosiated with EMF. A 32-year-old woman, of African origin, who presented with features of right heart failure, was diagnosed to have mitral valve prolapse of rheumatic origin with severe mitral regurgitation and severe pulmonary hypertension (PAH). Intraoperative findings lead to the diagnosis of EMF. We report this rare case of mitral valve prolapse in EMF, in a geographical area where rheumatic heart disease is endemic, to showcase how a rare manifestation of EMF can be misdiagnosed as that of rheumatic heart disease. PMID:27549547

  20. 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.

  1. 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.

  2. 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.

  3. Haemodynamics of giant cerebral aneurysm: A comparison between the rigid-wall, one-way and two-way FSI models

    NASA Astrophysics Data System (ADS)

    Khe, A. K.; Cherevko, A. A.; Chupakhin, A. P.; Bobkova, M. S.; Krivoshapkin, A. L.; Orlov, K. Yu

    2016-06-01

    In this paper a computer simulation of a blood flow in cerebral vessels with a giant saccular aneurysm at the bifurcation of the basilar artery is performed. The modelling is based on patient-specific clinical data (both flow domain geometry and boundary conditions for the inlets and outlets). The hydrodynamic and mechanical parameters are calculated in the frameworks of three models: rigid-wall assumption, one-way FSI approach, and full (two-way) hydroelastic model. A comparison of the numerical solutions shows that mutual fluid- solid interaction can result in qualitative changes in the structure of the fluid flow. Other characteristics of the flow (pressure, stress, strain and displacement) qualitatively agree with each other in different approaches. However, the quantitative comparison shows that accounting for the flow-vessel interaction, in general, decreases the absolute values of these parameters. Solving of the hydroelasticity problem gives a more detailed solution at a cost of highly increased computational time.

  4. The effects of three-dimensional defects on one-way surface plasmon propagation for photonic topological insulators comprised of continuum media

    PubMed Central

    Hassani Gangaraj, S. Ali; Nemilentsau, Andrei; Hanson, George W.

    2016-01-01

    We have investigated one-way surface plasmon-polaritons (SPPs) at the interface of a continuum magnetoplasma material and metal, in the presence of three-dimensional surface defects. Bulk electromagnetic modes of continuum materials have Chern numbers, analogous to those of photonic crystals. This can lead to the appearance of topologically-protected surface modes at material interfaces, propagating at frequencies inside the bandgap of the bulk materials. Previous studies considered two-dimensional structures; here we consider the effect of three-dimensional defects, and show that, although backward propagation/reflection cannot occur, side scattering does take place and has significant effect on the propagation of the surface mode. Several different waveguiding geometries are considered for reducing the effects of side-scattering, and we also consider the effects of metal loss. PMID:27444542

  5. The effects of three-dimensional defects on one-way surface plasmon propagation for photonic topological insulators comprised of continuum media

    NASA Astrophysics Data System (ADS)

    Hassani Gangaraj, S. Ali; Nemilentsau, Andrei; Hanson, George W.

    2016-07-01

    We have investigated one-way surface plasmon-polaritons (SPPs) at the interface of a continuum magnetoplasma material and metal, in the presence of three-dimensional surface defects. Bulk electromagnetic modes of continuum materials have Chern numbers, analogous to those of photonic crystals. This can lead to the appearance of topologically-protected surface modes at material interfaces, propagating at frequencies inside the bandgap of the bulk materials. Previous studies considered two-dimensional structures; here we consider the effect of three-dimensional defects, and show that, although backward propagation/reflection cannot occur, side scattering does take place and has significant effect on the propagation of the surface mode. Several different waveguiding geometries are considered for reducing the effects of side-scattering, and we also consider the effects of metal loss.

  6. The effects of three-dimensional defects on one-way surface plasmon propagation for photonic topological insulators comprised of continuum media.

    PubMed

    Hassani Gangaraj, S Ali; Nemilentsau, Andrei; Hanson, George W

    2016-01-01

    We have investigated one-way surface plasmon-polaritons (SPPs) at the interface of a continuum magnetoplasma material and metal, in the presence of three-dimensional surface defects. Bulk electromagnetic modes of continuum materials have Chern numbers, analogous to those of photonic crystals. This can lead to the appearance of topologically-protected surface modes at material interfaces, propagating at frequencies inside the bandgap of the bulk materials. Previous studies considered two-dimensional structures; here we consider the effect of three-dimensional defects, and show that, although backward propagation/reflection cannot occur, side scattering does take place and has significant effect on the propagation of the surface mode. Several different waveguiding geometries are considered for reducing the effects of side-scattering, and we also consider the effects of metal loss. PMID:27444542

  7. Adaptation of methodology to select structural alternatives of one-way slab in residential building to the guidelines of the European Committee for Standardization (CEN/TC 350)

    SciTech Connect

    Fraile-Garcia, Esteban; Ferreiro-Cabello, Javier; Martinez-Camara, Eduardo; Jimenez-Macias, Emilio

    2015-11-15

    The European Committee for Standardization (CEN) through its Technical Committee CEN/TC-350 is developing a series of standards for assessing the building sustainability, at both product and building levels. The practical application of the selection (decision making) of structural alternatives made by one-way slabs leads to an intermediate level between the product and the building. Thus the present study addresses this problem of decision making, following the CEN guidelines and incorporating relevant aspects of architectural design into residential construction. A life cycle assessment (LCA) is developed in order to obtain valid information for the decision making process (the LCA was developed applying CML methodology although Ecoindicator99 was used in order to facilitate the comparison of the values); this information (the carbon footprint values) is contrasted with other databases and with the information from the Environmental Product Declaration (EPD) of one of the lightening materials (expanded polystyrene), in order to validate the results. Solutions of different column disposition and geometries are evaluated in the three pillars of sustainable construction on residential construction: social, economic and environmental. The quantitative analysis of the variables used in this study enables and facilitates an objective comparison in the design stage by a responsible technician; the application of the proposed methodology reduces the possible solutions to be evaluated by the expert to 12.22% of the options in the case of low values of the column index and to 26.67% for the highest values. - Highlights: • Methodology for selection of structural alternatives in buildings with one-way slabs • Adapted to CEN guidelines (CEN/TC-350) for assessing the building sustainability • LCA is developed in order to obtain valid information for the decision making process. • Results validated comparing carbon footprint, databases and Env. Product Declarations

  8. Subject-Specific Fully-Coupled and One-Way Fluid-Structure Interaction Models for Modeling of Carotid Atherosclerotic Plaques in Humans

    PubMed Central

    Tao, Xiaojuan; Gao, Peiyi; Jing, Lina; Lin, Yan; Sui, Binbin

    2015-01-01

    Background Hemodynamics play an important role in the development and progression of carotid atherosclerosis, and may be important in the assessment of plaque vulnerability. The aim of this study was to develop a system to assess the hemodynamics of carotid atherosclerotic plaques using subject-specific fluid-structure interaction (FSI) models based on magnetic resonance imaging (MRI). Material/Methods Models of carotid bifurcations (n=86 with plaques from 52 patients, n=14 normal carotids from 12 participants) were obtained at the Department of Radiology, Beijing Tian Tan Hospital between 2010 and 2013. The maximum von Mises stress, minimum pressure, and flow velocity values were assessed at the most stenotic site in patients, or at the carotid bifurcations in healthy volunteers. Results of one-way FSI were compared with fully-coupled FSI for the plaques of 19 randomly selected models. Results The maximum von Mises stress and the minimum pressure and velocity were significantly increased in the stenosis group compared with controls based on one-way FSI (all P<0.05). The maximum von Mises stress and the minimum pressure were significantly higher and the velocity was significantly lower based on fully coupled FSI compared with on-way FSI (all P<0.05). Although there were differences in numerical values, both methods were equivalent. The maximum von Mises stress of vulnerable plaques was significantly higher than stable plaques (P<0.001). The maximum von Mises stress of the group with fibrous cap defect was significantly higher than the group without fibrous cap defect (P=0.001). Conclusions The hemodynamics of atherosclerotic plaques can be assessed noninvasively using subject-specific models of FSI based on MRI. PMID:26510514

  9. Space Weather at Mars: 3-D studies using one-way coupling between the Multi-fluid MHD, M-GITM and M-AMPS models

    NASA Astrophysics Data System (ADS)

    Dong, Chuanfei

    This dissertation presents numerical simulation results of the solar wind interaction with the Martian upper atmosphere by using three comprehensive 3-D models: the Mars Global Ionosphere Thermosphere Model (M-GITM), the Mars exosphere Monte Carlo model Adaptive Mesh Particle Simulator (M-AMPS), and the BATS-R-US Mars multi-fluid MHD (MF-MHD) model. The coupled framework has the potential to provide improved predictions for ion escape rates for comparison with future data to be returned by the MAVEN mission (2014-2016) and thereby improve our understanding of present day escape processes. Estimates of ion escape rates over Mars history must start from properly validated models that can be extrapolated into the past. This thesis aims to build a model library for the NASA Mars Atmosphere and Volatile EvolutioN (MAVEN) mission, which will thus enhance the science return from the MAVEN mission. In this thesis, we aim to address the following four main scientific questions by adopting the one-way coupled framework developed here: (1) What are the Martian ion escape rates at the current epoch and ancient times? (2) What controls the ion escape processes at the current epoch? How are the ion escape variations connected to the solar cycle, crustal field orientation and seasonal variations? (3) How do the variable 3-D cold neutral thermosphere and hot oxygen corona affect the solar wind-Mars interaction? (4) How does the Martian atmosphere respond to extreme variations (e.g., ICMEs) in the solar wind and its interplanetary environment? These questions are closely related to the primary scientific goals of NASA's MAVEN mission and European Space Agency's Mars Express (MEX) mission. We reasonably answer all these four questions at the end of this thesis by employing the one-way coupled framework and comparing the simulation results with both MEX and MAVEN observational data.

  10. Left ventricular post-infraction pseudoaneurysm mimicking mitral valve endocarditis

    PubMed Central

    2013-01-01

    In this report we present a patient who was initially diagnosed as suffering from mitral valve endocarditis. The proper use of diagnostic modalities revealed a pseudo aneurysm of the left ventricle which was mimicking mitral valve vegetations. This allowed better planning of the subsequent operation. The optimal preoperative diagnostic studies are discussed along with the proper surgical treatment. PMID:24228621

  11. Left ventricular post-infraction pseudoaneurysm mimicking mitral valve endocarditis.

    PubMed

    Dedeilias, Panagiotis; Koukis, Ioannis; Roussakis, Antonios; Tsipas, Pantelis; Rouska, Effie

    2013-01-01

    In this report we present a patient who was initially diagnosed as suffering from mitral valve endocarditis. The proper use of diagnostic modalities revealed a pseudo aneurysm of the left ventricle which was mimicking mitral valve vegetations. This allowed better planning of the subsequent operation. The optimal preoperative diagnostic studies are discussed along with the proper surgical treatment. PMID:24228621

  12. [Pannus Formation Two Years after Bioprosthetic Aortic Valve Implantation;Report of a Case].

    PubMed

    Ono, Kimiyo; Kuroda, Hiroaki

    2015-08-01

    We report a case of early deterioration of the bioprosthetic aortic valve 23 months postoperatively. A 77-year-old man who had undergone aortic valve replacement with a 23-mm Epic valve( St. Jude Medical [SJM])presented to us after a syncopal episode. Echocardiography revealed severe aortic stenosis, and redo aortic valve replacement with a 21-mm SJM mechanical valve was performed. All 3 cusps of the tissue valve were thickened by fibrous pannus overgrowth. Neither calcification nor invasion of inflammatory cells was observed. The cause of pannus formation at such an early stage after implantation remains unknown. PMID:26329714

  13. Valve disease in pregnancy.

    PubMed

    Pessel, Cara; Bonanno, Clarissa

    2014-08-01

    Maternal cardiac disease is a major cause of non-obstetric morbidity and accounts for 10-25% of maternal mortality. Valvular heart disease may result from congenital abnormalities or acquired lesions, some of which may involve more than one valve. Maternal and fetal risks in pregnant patients with valve disease vary according to the type and severity of the valve lesion along with resulting abnormalities of functional capacity, left ventricular function, and pulmonary artery pressure. Certain high-risk conditions are considered contraindications to pregnancy, while others may be successfully managed with observation, medications, and, in refractory cases, surgical intervention. Communication between the patient׳s obstetrician, maternal-fetal medicine specialist, obstetrical anesthesiologist, and cardiologist is critical in managing a pregnancy with underlying maternal cardiac disease. The management of the various types of valve diseases in pregnancy will be reviewed here, along with a discussion of related complications including mechanical prosthetic valves and infective endocarditis. PMID:25037517

  14. 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.

  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. Fuel injection valve connection

    SciTech Connect

    Eshleman, E.S.; Field, M.J.; Penwright, J.L.

    1987-09-15

    A fuel injection valve connection is described which consists of a fuel injection valve having a cylindrical inlet fitting. The fitting has a threaded internal surface and a cylindrical external surface. A fuel connector has a projection with a threaded external surface that mates with the threaded internal surface of the fitting. The connector also has a sleeve with a cylindrical internal surface surrounding the fitting and an O-ring sealingly engaging the internal surface of the sleeve and the external surface of the fitting, whereby the valve may be rotated relative to the connector without breaking the sealing engagement between the valve and the connector, and wherein the connector also has a tab engageable with the injector to prevent unthreading of the valve from the connector.

  17. Multiple-port valve

    DOEpatents

    Doody, Thomas J.

    1978-08-22

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

  18. Bioprinting a cardiac valve.

    PubMed

    Jana, Soumen; Lerman, Amir

    2015-12-01

    Heart valve tissue engineering could be a possible solution for the limitations of mechanical and biological prostheses, which are commonly used for heart valve replacement. In tissue engineering, cells are seeded into a 3-dimensional platform, termed the scaffold, to make the engineered tissue construct. However, mimicking the mechanical and spatial heterogeneity of a heart valve structure in a fabricated scaffold with uniform cell distribution is daunting when approached conventionally. Bioprinting is an emerging technique that can produce biological products containing matrix and cells, together or separately with morphological, structural and mechanical diversity. This advance increases the possibility of fabricating the structure of a heart valve in vitro and using it as a functional tissue construct for implantation. This review describes the use of bioprinting technology in heart valve tissue engineering. PMID:26254880

  19. Challenging transfemoral valve-in-valve implantation in a degenerated stentless bioprosthetic aortic valve.

    PubMed

    Halapas, A; Chrissoheris, M; Spargias, Konstantinos

    2014-08-01

    Bioprosthetic heart valves are often preferred over mechanical valves as they may preclude the need for anticoagulation. Reoperation is the standard treatment for structural failure of bioprosthetic valves; however, it carries significant risk especially in inoperable elderly patients. Valve-in-valve (ViV) transcatheter aortic valve replacement (TAVR) seems to be an effective and promising procedure in patients with degenerated bioprosthetic aortic valves avoiding the risks associated with the use of cardioplegia and redo cardiac surgery. We report an interesting case of a high-risk 74-year-old patient with a degenerated Sorin Freedom Solo stentless valve treated successfully with ViV TAVR. PMID:25091103

  20. Intracardiac echocardiography to diagnose pannus formation after aortic valve replacement.

    PubMed

    Yamamoto, Yoshiya; Ohara, Takahiro; Funada, Akira; Takahama, Hiroyuki; Amaki, Makoto; Hasegawa, Takuya; Sugano, Yasuo; Kanzaki, Hideaki; Anzai, Toshihisa

    2016-03-01

    A 66-year-old female, under regular follow-up for 20 years after aortic valve replacement (19-mm Carbomedics), presented dyspnea on effort and hypotension during hemodialysis. A transthoracic echocardiogram showed elevation of transvalvular velocity up to 4 m/s, but the structure around the aortic prosthesis was difficult to observe due to artifacts. Fluoroscopy revealed normal motion of the leaflets of the mechanical valve. Intracardiac echocardiography (ICE) revealed a pannus-like structure in the left ventricular outflow tract. Transesophageal echocardiogram also revealed this structure. ICE can visualize structural abnormalities around a prosthetic valve after cardiac surgery even in patients in whom conventional imaging modalities failed. PMID:26732266

  1. Dual valve plate two-way pressure relief valve

    NASA Astrophysics Data System (ADS)

    Angeli, Robert J.

    1993-02-01

    This patent application discloses a two-way valve which includes dual valve plates to be positioned between first and second chambers having varying pressure therein, to relieve excess pressure in either chamber by permitting fluid flow from one chamber to the other. The valve includes a body portion having disposed therein dual valve plates. In the equilibrium state, the first valve plate is spring biased against the valve body in the direction of the first chamber to seal off any flow through the valve. The second valve plate is separately spring biased against the first valve plate in the direction of the second chamber, sealing off flow between the valve plates. When the pressure of the first chamber is greater than the pressure of the second chamber by a predetermined amount, the first and second valve plates move away from the valve body permitting fluid flow from the first chamber to the second chamber. When the pressure of the second chamber exerted on the second valve plate through apertures in the first valve plate is greater than the pressure of the first chamber by a predetermined amount, the second valve plate moves away from the face of the first valve plate permitting fluid flow from the second chamber to the first chamber.

  2. Transcatheter Aortic Valve-in-Valve Replacement Instead of a 4th Sternotomy in a 21-Year-Old Woman with Aortic Homograft Failure

    PubMed Central

    Díez, José G.; Schechter, Michael; Dougherty, Kathryn G.; Preventza, Ourania

    2016-01-01

    Transcatheter aortic valve replacement (TAVR) is a well-established method for replacing native aortic valves; however, it was conceived for elderly patients with aortic valve stenosis, and the lack of data on long-term durability has led practitioners to restrict the use of TAVR to patients who have short life expectancies. Here, we describe the case of a 21-year-old woman who had undergone 3 previous open aortic valve replacements and who presented with symptoms of recurrent valvular failure. Transthoracic echocardiograms and computed tomographic angiograms revealed a degenerating aortic root homograft with substantial calcification, moderate-to-severe aortic valve stenosis, and severe aortic valve regurgitation. Open surgical valve replacement posed substantial risk to our patient, so we decided to perform valve-in-valve TAVR with use of the Edwards Sapien XT Transcatheter Heart Valve. The patient's pulmonary artery pressure, valvular regurgitation, and symptoms improved substantially thereafter. We found that valve-in-valve TAVR into a failing aortic root homograft was less invasive than repeat surgical valve replacement in this young patient who had congenital vascular anomalies and a complex surgical history. PMID:27547146

  3. 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.

  4. Diseases of the Tricuspid Valve

    MedlinePlus

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

  5. What Is Heart Valve Surgery?

    MedlinePlus

    ANSWERS by heart Treatments + Tests What Is Heart Valve Surgery? The four valves in your heart make sure that blood flows through your heart in the right direction. Heart valve surgery is done to replace or repair heart valves that Aortic ...

  6. Valve assemblies. [for oxygen systems

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Seals and sealing, especially relative to valve designs for O2 systems are investigated. Also considered are high pressure requirements, pressure and flow regulators, and check and relief valves. Valve failure as induced by overstress or abrasion, galling, and ignition of valve parts was detailed.

  7. 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.

  8. Time-transfer experiments between satellite laser ranging ground stations via one-way laser ranging to the Lunar Reconnaissance Orbiter

    NASA Astrophysics Data System (ADS)

    Mao, D.; Sun, X.; Skillman, D. R.; Mcgarry, J.; Hoffman, E.; Neumann, G. A.; Torrence, M. H.; Smith, D. E.; Zuber, M. T.

    2014-12-01

    Satellite laser ranging (SLR) has long been used to measure the distance from a ground station to an Earth-orbiting satellite in order to determine the spacecraft position in orbit, and to conduct other geodetic measurements such as plate motions. This technique can also be used to transfer time between the station and satellite, and between remote SLR sites, as recently demonstrated by the Time Transfer by Laser Link (T2L2) project by the Centre National d'Etudes Spatiaes (CNES) and Observatorire de la Cote d'Azur (OCA) as well as the Laser Time Transfer (LTT) project by the Shanghai Astronomical Observatory, where two-way and one-way measurements were obtained at the same time. Here we report a new technique to transfer time between distant SLR stations via simultaneous one-way laser ranging (LR) to the Lunar Reconnaissance Orbiter (LRO) spacecraft at lunar distance. The major objectives are to establish accurate ground station times and to improve LRO orbit determination via these measurements. The results of these simultaneous LR measurements are used to compare the SLR station times or transfer time from one to the other using times-of-flight estimated from conventional radio frequency tracking of LRO. The accuracy of the time transfer depends only on the difference of the times-of-flight from each ground station to the spacecraft, and is expected to be at sub-nano second level. The technique has been validated by both a ground-based experiment and an experiment that utilized LRO. Here we present the results to show that sub-nanosecond precision and accuracy are achievable. Both experiments were carried out between the primary LRO-LR station, The Next Generation Satellite Laser Ranging (NGSLR) station, and its nearby station, Mobile Laser System (MOBLAS-7), both at Greenbelt, Maryland. The laser transmit time from both stations were recorded by the same event timer referenced to a Hydrogen maser. The results have been compared to data from a common All

  9. Percutaneous Pulmonary Valve Placement

    PubMed Central

    Prieto, Lourdes R.

    2015-01-01

    Patients with congenital heart disease and pulmonary valve disease need multiple procedures over their lifetimes to replace their pulmonary valves. Chronic pulmonary stenosis, regurgitation, or both have untoward effects on ventricular function and on the clinical status of these patients. To date, all right ventricle–pulmonary artery conduits have had relatively short lifespans. Percutaneous pulmonary valve implantation, although relatively new, will probably reduce the number of operative procedures that these patients will have to undergo over a lifetime. Refinement and further development of this procedure holds promise for the extension of this technology to other patient populations. PMID:26175629

  10. 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.

  11. Posterior Urethral Valve: An Unusual Cause of Primary Male Infertility

    PubMed Central

    Agbugui, Jude Orumuah; Omokhudu, Oisamoren

    2015-01-01

    Background Posterior urethral valve presenting in adulthood is uncommon. This can be an unusual cause of primary male infertility as a result of abnormalities in sexual function. Case Presentation This report describes a 40 year old man who presented to us on account of inability to impregnate his wife after 2 years of marriage. History revealed poor stream of urine since childhood and passage of scanty ejaculate during intercourse. A micturating cystourethrogram revealed dilated posterior urethra in keeping with posterior urethral valves. Endoscopic valve ablation was done with subsequent improvement in ejaculate volume and urine stream. His spouse achieved pregnancy thereafter. Conclusion In this report, it was found that adult posterior urethral valve though uncommon may be a cause of male infertility. Restoration of fertility potential can be achieved following valve ablation. PMID:25927029

  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. 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.

  14. Pulmonic Valve Repair in a Patient with Isolated Pulmonic Valve Endocarditis and Sickle Cell Disease

    PubMed Central

    Glew, Timothy; Feliciano, Migdalia; Finkielstein, Dennis; Hecht, Susan; Hoffman, Daryl

    2015-01-01

    A 49-year-old woman with sickle cell disease presented with one month of exertional dyspnea, weakness, and fever and was diagnosed with isolated pulmonic valve endocarditis secondary to methicillin-resistant Staphylococcus bacteremia in the setting of a peripherally inserted central venous catheter. Chest computerized tomography showed multiple bilateral pulmonary nodular opacities consistent with septic emboli. Transthoracic and transesophageal echocardiograms revealed a large echodensity on the pulmonic valve requiring vegetation excision and pulmonic valve repair. In conclusion, isolated pulmonic valve endocarditis is a rare cause of infective endocarditis that warrants a high index of clinical suspicion. Furthermore the management of patients with sickle cell disease and endocarditis requires special consideration. PMID:26199760

  15. Extended consecutive modal pushover procedure for estimating seismic responses of one-way asymmetric plan tall buildings considering soil-structure interaction

    NASA Astrophysics Data System (ADS)

    Tehrani, Mohammad Hadikhan; Khoshnoudian, Faramarz

    2014-09-01

    Performance based design becomes an effective method for estimating seismic demands of buildings. In asymmetric plan tall building the effects of higher modes and torsion are crucial. The consecutive modal pushover (CMP) procedure is one of the procedures that consider these effects. Also in previous studies the influence of soil-structure interaction (SSI) in pushover analysis is ignored. In this paper the CMP procedure is modified for one-way asymmetric plan mid and high-rise buildings considering SSI. The extended CMP (ECMP) procedure is proposed in order to overcome some limitations of the CMP procedure. In this regard, 10, 15 and 20 story buildings with asymmetric plan are studied considering SSI assuming three different soil conditions. Using nonlinear response history analysis under a set of bidirectional ground motion; the exact responses of these buildings are calculated. Then the ECMP procedure is evaluated by comparing the results of this procedure with nonlinear time history results as an exact solution as well as the modal pushover analysis procedure and FEMA 356 load patterns. The results demonstrate the accuracy of the ECMP procedure.

  16. Solar wind interaction with Mars upper atmosphere: Results from the one-way coupling between the multifluid MHD model and the MTGCM model

    NASA Astrophysics Data System (ADS)

    Dong, Chuanfei; Bougher, Stephen W.; Ma, Yingjuan; Toth, Gabor; Nagy, Andrew F.; Najib, Dalal

    2014-04-01

    The 3-D multifluid Block Adaptive Tree Solar-wind Roe Upwind Scheme (BATS-R-US) MHD code (MF-MHD) is coupled with the 3-D Mars Thermospheric general circulation model (MTGCM). The ion escape rate from the Martian upper atmosphere is investigated by using a one-way coupling approach, i.e., the MF-MHD model incorporates the effects of 3-D neutral atmosphere profiles from the MTGCM model. The calculations are carried out for two cases with different solar cycle conditions. The calculated total ion escape flux (the sum of three major ionospheric species, O+, O2+, and CO2+) for solar cycle maximum conditions (6.6×1024 s-1) is about 2.6 times larger than that of solar cycle minimum conditions (2.5×1024 s-1). Our simulation results show good agreement with recent observations of 2-3×1024 s-1 (O+, O2+, and CO2+) measured near solar cycle minimum conditions by Mars Express. An extremely high solar wind condition is also simulated which may mimic the condition of coronal mass ejections or corotating interaction regions passing Mars. Simulation results show that it can lead to a significant value of the escape flux as large as 4.3×1025s-1.

  17. One-Way Multishape-Memory Effect and Tunable Two-Way Shape Memory Effect of Ionomer Poly(ethylene-co-methacrylic acid).

    PubMed

    Lu, Lu; Li, Guoqiang

    2016-06-15

    Reversible elongation by cooling and contraction by heating, without the need for repeated programming, is well-known as the two-way shape-memory effect (2W-SME). This behavior is contrary to the common physics-contraction when cooling and expansion when heating. Materials with such behavior may find many applications in real life, such as self-sufficient grippers, fastening devices, optical gratings, soft actuators, and sealant. Here, it is shown that ionomer Surlyn 8940, a 50-year old polymer, exhibits both one-way multishape-memory effects and tunable two-way reversible actuation. The required external tensile stress to trigger the tunable 2W-SME is very low when randomly jumping the temperatures within the melting transition window. With a proper one-time programming, "true" 2W-SME (i.e., 2W-SME without the need for an external tensile load) is also achieved. A long training process is not needed to trigger the tunable 2W-SME. Instead, a proper one-time tensile programming is sufficient to trigger repeated and tunable 2W-SME. Because the 2W-SME of the ionomer Surlyn is driven by the thermally reversible network, here crystallization and melting transitions of the semicrystalline poly(ethylene-co-methacrylic acid), it is believed that a class of thermally reversible polymers should also exhibit tunable 2W-SMEs. PMID:27191832

  18. Plans to improve the experimental limit in the comparison of the east-west and west-east one-way light propagation times on the rotating earth

    NASA Technical Reports Server (NTRS)

    Alley, C. O.; Kiess, T. E.; Nelson, R. A.; Sergienko, A. V.; Shih, Y. H.; Wang, B. C.; Yang, F. M.

    1993-01-01

    The preceding paper describes the results so far (interrupted in the Spring of 1989 because of lack of funds) of an experiment comparing the one-way light propagation times on the surface of the rotating Earth. For the 20 Km path length component in the East-West direction the predicted difference between the opposite sense propagation times would be 160 ps, if the approximately 360 Km/s surface speed of the Earth gives effective light speeds of 3 x 10(exp 8) m/s +/- 360 m/s. This could lead to a prediction of the difference between the clock transport and the light pulse synchronization methods described in the preceding paper: delta(T) = 0.5 (160) = 80 ps. The current upper bound of approximately 100 ps for delta(T) is limited by poorly understood systematic errors. The most important seems to be intensity-dependent time delays in the remote light pulse avalanche photo-diode detector. This will be replaced by a continuously operating circular scan streak camera having single photon sensitivity and a time resolution of approximately 5 ps. (This camera has recently been developed by the Xian Institute of Optics and Precision Mechanics in the P.R.C.). Better isolation from shocks and vibration for the Sigma-Tau hydrogen maser during transport will be provided. It is hoped that delta(T) is less than 20 ps can be achieved.

  19. Fast valve based on double-layer eddy-current repulsion for disruption mitigation in Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Zhuang, H. D.; Zhang, X. D.

    2015-05-01

    A fast valve based on the double-layer eddy-current repulsion mechanism has been developed on Experimental Advanced Superconducting Tokamak (EAST). In addition to a double-layer eddy-current coil, a preload system was added to improve the security of the valve, whereby the valve opens more quickly and the open-valve time becomes shorter, making it much safer than before. In this contribution, testing platforms, open-valve characteristics, and throughput of the fast valve are discussed. Tests revealed that by choosing appropriate parameters the valve opened within 0.15 ms, and open-valve times were no longer than 2 ms. By adjusting working parameter values, the maximum number of particles injected during this open-valve time was estimated at 7 × 1022. The fast valve will become a useful tool to further explore disruption mitigation experiments on EAST in 2015.

  20. Fast valve based on double-layer eddy-current repulsion for disruption mitigation in Experimental Advanced Superconducting Tokamak.

    PubMed

    Zhuang, H D; Zhang, X D

    2015-05-01

    A fast valve based on the double-layer eddy-current repulsion mechanism has been developed on Experimental Advanced Superconducting Tokamak (EAST). In addition to a double-layer eddy-current coil, a preload system was added to improve the security of the valve, whereby the valve opens more quickly and the open-valve time becomes shorter, making it much safer than before. In this contribution, testing platforms, open-valve characteristics, and throughput of the fast valve are discussed. Tests revealed that by choosing appropriate parameters the valve opened within 0.15 ms, and open-valve times were no longer than 2 ms. By adjusting working parameter values, the maximum number of particles injected during this open-valve time was estimated at 7 × 10(22). The fast valve will become a useful tool to further explore disruption mitigation experiments on EAST in 2015. PMID:26026520

  1. Mitral valve prolapse

    MedlinePlus

    ... Systolic click-murmur syndrome; Prolapsing mitral leaflet syndrome; Chest pain - mitral valve prolapse ... often affects thin women who may have minor chest wall deformities, scoliosis, or other disorders. Some forms ...

  2. Aortic valve surgery - open

    MedlinePlus

    ... choose to have your aortic valve surgery at a center that does many of these procedures. ... DA, Harken AH. Acquired heart disease: valvular. In: Townsend CM, ... Textbook of Cardiovascular Medicine . 10th ed. Philadelphia, PA: ...

  3. Heart valve surgery

    MedlinePlus

    ... occur, but this is rare. There is always a risk of infection. Talk to your doctor before having any type of medical procedure. The clicking of mechanical heart valves may be heard in the chest. This is normal.

  4. Valve Repair or Replacement

    MedlinePlus

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

  5. 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.

  6. Transcatheter Aortic Valve Implantation.

    PubMed

    Malaisrie, S Chris; Iddriss, Adam; Flaherty, James D; Churyla, Andrei

    2016-05-01

    Severe aortic stenosis (AS) is a life-threatening condition when left untreated. Aortic valve replacement (AVR) is the gold standard treatment for the majority of patients; however, transcatheter aortic valve implantation/replacement (TAVI/TAVR) has emerged as the preferred treatment for high-risk or inoperable patients. The concept of transcatheter heart valves originated in the 1960s and has evolved into the current Edwards Sapien and Medtronic CoreValve platforms available for clinical use. Complications following TAVI, including cerebrovascular events, perivalvular regurgitation, vascular injury, and heart block have decreased with experience and evolving technology, such that ongoing trials studying TAVI in lower risk patients have become tenable. The multidisciplinary team involving the cardiac surgeon and cardiologist plays an essential role in patient selection, procedural conduct, and perioperative care. PMID:27021619

  7. Flow metering valve

    DOEpatents

    Blaedel, Kenneth L.

    1985-01-01

    An apparatus for metering fluids at high pressures of about 20,000 to 60,000 psi is disclosed. The apparatus includes first and second plates which are positioned adjacent each other to form a valve chamber. The plates are made of materials which have substantially equal elastic properties. One plate has a planar surface area, and the other a recessed surface area defined by periphery and central lips. When the two plates are positioned in adjacent contacting relationship, a valve chamber is formed between the planar surface area and the recessed surface area. Fluid is introduced into the chamber and exits therefrom when a deformation occurs at positions where they no longer form a valve seat. This permits the metering of fluids at high pressures and at slow variable rates. Fluid then exits from the chamber until an applied external force becomes large enough to bring the valve seats back into contact.

  8. Flow metering valve

    DOEpatents

    Blaedel, K.L.

    1983-11-03

    An apparatus for metering fluids at high pressures of about 20,000 to 60,000 psi is disclosed. The apparatus includes first and second plates which are positioned adjacent each other to form a valve chamber. The plates are made of materials which have substantially equal elastic properties. One plate has a planar surface area, and the other a recessed surface area defined by periphery and central lips. When the two plates are positioned in adjacent contacting relationship, a valve chamber is formed between the planar surface area and the recessed surface area. Fluid is introduced into the chamber and exits therefrom when a deformation occurs at positions where they no longer form a valve seat. This permits the metering of fluids at high pressures and at slow variable rates. Fluid then exits from the chamber until an applied external force becomes large enough to bring the valve seats back into contact.

  9. 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.

  10. Mitral valve regurgitation

    MedlinePlus

    ... valves are at risk for an infection called endocarditis. Anything that causes bacteria to get into your ... Saunders; 2015:chap 63. Read More Arrhythmias Chronic Endocarditis Hardening of the arteries Heart failure - overview High ...

  11. Mitral Valve Prolapse

    MedlinePlus

    ... valve. MVP puts you at risk for infective endocarditis, a kind of heart infection. To prevent it, ... surgeries. Now, only people at high risk of endocarditis need the antibiotics. NIH: National Heart, Lung, and ...

  12. 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)

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

    PubMed

    François, J; Cathenis, K; Hamerlijnck, R

    2015-01-01

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

  14. 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.

  15. The patient inflating valve in anaesthesia and resuscitation breathing systems.

    PubMed

    Fenton, P M; Bell, G

    2013-03-01

    Patient inflating valves combined with self-inflating bags are known to all anaesthetists as resuscitation devices and are familiar as components of draw-over anaesthesia systems. Their variants are also commonplace in transfer and home ventilators. However, the many variations in structure and function have led to difficulties in their optimal use, definition and classification. After reviewing the relevant literature, we defined a patient inflating valve as a one-way valve that closes an exit port to enable lung inflation, also permitting exhalation and spontaneous breathing, the actions being automatic. We present a new classification based on the mechanism of valve opening/closure; namely elastic recoil of a flexible flap/diaphragm, sliding spindle opened by a spring/magnet or a hollow balloon collapsed by external pressure. The evolution of these valves has been driven by the difficulties documented in critical incidents, which we have used along with information from modern International Organization for Standardization standards to identify 13 ideal properties, the top six of which are non-jamming, automatic, no bypass effect, no rebreathing or air entry at patient end, low resistance, robust and easy to service. The Ambu and the Laerdal valves have remained popular due to their simplicity and reliability. Two new alternatives, the Fenton and Diamedica valves, offer the benefits of location away from the patient while retaining a small functional dead space. They also offer the potential for greater use of hybrid continuous flow/draw-over systems that can operate close to atmospheric pressure. The reliable application of positive end-expiratory pressure/continuous positive airway pressure remains a challenge. PMID:23530783

  16. Actuator-valve interface optimization

    SciTech Connect

    Burchett, O.L.; Jones, R.L.

    1986-01-01

    A computer code, Actuator Valve Response (AVR), has been developed to optimize the explosive actuator-valve interface parameters so that the valve plunger velocity is at a maximum when the plunger reaches the valve tubes. The code considers three forces to act on the valve plunger before the plunger reaches the valve tubes. These are the pressure force produced by the actuator, the shear force necessary to shear the seal disks on the actuator and the valve plunger, and the friction force caused by friction between the plunger and the plunger bore. The three forces are modeled by expressions that are explicitly functions of the plunger displacement. A particular actuator-valve combination was analyzed with the computer code AVR with four different combinations of valve plunger seal disk shear strength and initial friction force. (LEW)

  17. Transcatheter aortic valve implantation.

    PubMed

    Nielsen, Hans Henrik Møller

    2012-12-01

    Transcatheter aortic valve implantation (TAVI) was introduced experimentally in 1989, based on a newly developed heart valve prosthesis - the stentvalve. The valve was invented by a Danish cardiologist named Henning Rud Andersen. The new valve was revolutionary. It was foldable and could be inserted via a catheter through an artery in the groin, without the need for heart lung machine. This allowed for a new valve implantation technique, much less invasive than conventional surgical aortic valve replacement (SAVR). Surgical aortic valve replacement is safe and improves symptoms along with survival. However, up to 1/3 of patients with aortic valve stenosis cannot complete the procedure due to frailty. The catheter technique was hoped to provide a new treatment option for these patients. The first human case was in 2002, but more widespread clinical use did not begin until 2006-2010. Today, in 2011, more than 40,000 valves have been implanted worldwide. Initially, because of the experimental character of the procedure, TAVI was reserved for patients who could not undergo SAVR due to high risk. The results in this group of patients were promising. The procedural safety was acceptable, and the patients experienced significant improvements in their symptoms. Three of the papers in this PhD-thesis are based on the outcome of TAVI at Skejby Hospital, in this high-risk population [I, II and IV]. Along with other international publications, they support TAVI as being superior to standard medical treatment, despite a high risk of prosthetic regurgitation. These results only apply to high-risk patients, who cannot undergo SAVR. The main purpose of this PhD study has been to investigate the quality of TAVI compared to SAVR, in order to define the indications for this new procedure. The article attached [V] describes a prospective clinical randomised controlled trial, between TAVI to SAVR in surgically amenable patients over 75 years of age with isolated aortic valve stenosis

  18. Ceramic valve guide and seat

    SciTech Connect

    Mott, D.H.; Schmidt, H.

    1987-08-25

    For molded inclusion in a cast metal cylinder head of a internal combustion engine, an integral ceramic valve seat and valve stem guide assembly are described for operative engagement with and support of a conventional poppet-type valve with its enlarged head portion with a sealing surface thereon and an elongated cylindrical stem portion. The guide and seat consist of: valve seat forming means cast in ceramic material having an annular configuration operatively conforming to the configuration of the sealing surface of the valve and defining an annular seating surface for sealing engagement with the enlarged valve head when the valve is in a closed position; valve stem support means cast in ceramic having a generally tubular configuration with an internal bore and defining a support for reciprocation of the cylindrical stem portion of the valve as the valve moves between open and closed operative position; connecting means cast in ceramic and integral with both the valve set forming means and the valve stem supporting guide means for aligning the means so that a plane through the annular seating surface is normal to the axis of the tubular guide means and coaxially supporting the annular valve set forming means and the tubular guide portion whereas the integral valve seat forming means.

  19. Exploration of Mars using Delta Differential One-Way Ranging based on Triangle Libration Points in the Earth-Moon system

    NASA Astrophysics Data System (ADS)

    Liu, Peng; Tang, Jingshi; Hou, Xiyun; Liu, Lin

    Very Long Baseline Interferometry (VLBI) is a technique that allows determination of angular position for distant radio sources by measuring the geometric time delay between received radio signals at two geographically separated stations. An application of VLBI is spacecraft navigation in space missions where delay measurements of a spacecraft radio signal are compared against similar delay measurements of angularly nearby quasar radio signals. In the case where the spacecraft measurements are obtained from the phases of tones emitted from the spacecraft, first detected separately at each station, and then differenced, this application of VLBI is known as Delta Differential One-Way Ranging (Delta-DOR). Even though data acquisition and processing are not identical for the spacecraft and quasar, they have similar information content and similar sensitivity to sources of error. Consequently, the Delta-DOR can be used in conjunction with Doppler and ranging data to improve spacecraft navigation by more efficiently determining spacecraft angular position in the plane-of-sky. Over the decades, human exploration of Mars have never been stopped. As we know, Delta-DOR began to serve its purpose for Mars Odyssey spacecraft in 2001. In the following years, Delta-DOR was used from Mars Exploration Rover (MER) in 2003-2004 to Mars Science Laboratory (MSL) in 2011, all with excellent results. At present, human exploration of Mars using Delta-DOR technique mainly depends on the Earth-based ground stations. As we know, the differential time delay between the spacecraft and quasar is given approximately by begin{math}Deltatau=-frac{1}{c}BsinTheta_{1}(DeltaTheta_{B}) , the accuracy of the determination of angular separation begin{math}DeltaTheta_{B} improves as the measurement error in the observable begin{math}Deltatau decreases. Further, begin{math}DeltaTheta_{B} accuracy improves as the baseline length B increases. Therefore, the introduction of special libration points, i

  20. One-way coupling of an integrated assessment model and a water resources model: evaluation and implications of future changes over the US Midwest

    NASA Astrophysics Data System (ADS)

    Voisin, N.; Liu, L.; Hejazi, M.; Tesfa, T.; Li, H.; Huang, M.; Liu, Y.; Leung, L. R.

    2013-11-01

    An integrated model is being developed to advance our understanding of the interactions between human activities, terrestrial system and water cycle, and to evaluate how system interactions will be affected by a changing climate at the regional scale. As a first step towards that goal, a global integrated assessment model, which includes a water-demand model driven by socioeconomics at regional and global scales, is coupled in a one-way fashion with a land surface hydrology-routing-water resources management model. To reconcile the scale differences between the models, a spatial and temporal disaggregation approach is developed to downscale the annual regional water demand simulations into a daily time step and subbasin representation. The model demonstrates reasonable ability to represent the historical flow regulation and water supply over the US Midwest (Missouri, Upper Mississippi, and Ohio river basins). Implications for future flow regulation, water supply, and supply deficit are investigated using climate change projections with the B1 and A2 emission scenarios, which affect both natural flow and water demand. Although natural flow is projected to increase under climate change in both the B1 and A2 scenarios, there is larger uncertainty in the changes of the regulated flow. Over the Ohio and Upper Mississippi river basins, changes in flow regulation are driven by the change in natural flow due to the limited storage capacity. However, both changes in flow and demand have effects on the Missouri River Basin summer regulated flow. Changes in demand are driven by socioeconomic factors, energy and food demands, global markets and prices with rainfed crop demand handled directly by the land surface modeling component. Even though most of the changes in supply deficit (unmet demand) and the actual supply (met demand) are driven primarily by the change in natural flow over the entire region, the integrated framework shows that supply deficit over the Missouri River

  1. Volumetric velocity measurements on flows through heart valves

    NASA Astrophysics Data System (ADS)

    Troolin, Daniel; Amatya, Devesh; Longmire, Ellen

    2009-11-01

    Volumetric velocity fields inside two types of artificial heart valves were obtained experimentally through the use of volumetric 3-component velocimetry (V3V). Index matching was used to mitigate the effects of optical distortions due to interfaces between the fluid and curved walls. The steady flow downstream of a mechanical valve was measured and the results matched well with previously obtained 2D PIV results, such as those of Shipkowitz et al. (2002). Measurements upstream and downstream of a deformable silicone valve in a pulsatile flow were obtained and reveal significant three-dimensional features of the flow. Plots and movies will be shown, and a detailed discussion of the flow and various experimental considerations will be included. Reference: Shipkowitz, T, Ambrus J, Kurk J, Wickramasinghe K (2002) Evaluation technique for bileaflet mechanical valves. J. Heart Valve Disease. 11(2) pp. 275-282.

  2. 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

  3. 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

  4. 39. TAINTER GATE VALVES, OPERATING MACHINERY, AND VALVE ASSEMBLED AUXILIARY ...

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

    39. TAINTER GATE VALVES, OPERATING MACHINERY, AND VALVE ASSEMBLED AUXILIARY LOCK. January 1932 - Mississippi River 9-Foot Channel Project, Lock & Dam No. 15, Upper Mississipi River (Arsenal Island), Rock Island, Rock Island County, IL

  5. Pressure valve for needle gate valve control. June 13, 1913. ...

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

    Pressure valve for needle gate valve control. June 13, 1913. Photocopy of original drawing. Drawing on file at the Salt River Project Archives. Phoenix, Arizona - Cross Cut Hydro Plant, North Side of Salt River, Tempe, Maricopa County, AZ

  6. Obstruction of a Codman-Hakim programmable valve by a migrating pressure control cam.

    PubMed

    Shimizu, Satoru; Utsuki, Satoshi; Suzuki, Sachio; Oka, Hidehiro; Fujii, Kiyotaka

    2005-09-01

    Although the Codman-Hakim programmable valve is popular, several problems arising from its design have been described. The authors report an additional cause of shunt obstruction in the system. A 6-year-old girl who had received a ventriculoperitoneal shunt with the Codman-Hakim programmable valve system presented with worsening consciousness. The valve proved hard to flush, and emergency revision of the valve was performed. Examination of the extracted valve revealed that the pressure control cam had migrated into the outlet of the valve, thus causing the obstruction. A crack in the plastic housing surrounding the cam suggesting a past impact to the system was also revealed. These factors should thus be kept in mind as potential sources of obstruction of the valve system, especially in patients susceptible to episodes of head impact. PMID:16238082

  7. [Mineralization of heart valves].

    PubMed

    Pawlikowski, M; Pfitzner, R

    1992-01-01

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

  8. Check valves aging assessment

    SciTech Connect

    Haynes, H.D.

    1991-01-01

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

  9. 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

  10. 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.

  11. Safety check valve

    SciTech Connect

    Spears, H.L.

    1992-02-11

    This patent describes a safety check valve, for use with a pumping unit for petroleum fluids, the pumping unit including a polished rod and a stuffing box. It comprises: a valve housing having upper and lower ends and a central bore extending between the upper and lower ends and adapted to have the polished rod pass through the central bore; a ball seating surface associated with the central bore; a non-spring bias ball; a ball housing for the ball and associated with the valve housing; and means for moving the ball from the ball housing into the central bore upon the polished rod not being disposed in the central bore, including a ball receiving cavity associated with the ball housing, the ball hoising having first and second ends, the first end of the ball housing being in communication with the central bore of the valve housing, the second end being closed; the ball receiving cavity having a ball support surface upon which the ball may rest, when the ball is disposed in the ball receiving cavity, the ball support surface sloping downwardly toward the first end of the ball housing, whereby if the polished rod is not disposed within the central bore of the valve housing, the ball moves down the ball support surface, under the force of gravity, from the ball receiving cavity into the central bore and seats on the ball seating surface.

  12. 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

  13. 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

  14. Myxomatous Mitral Valve with Prolapse and Flail Scallop

    PubMed Central

    Fan, Jerry; Timbrook, Alexa; Said, Sarmad; Babar, Kamran; Teleb, Mohamed; Mukherjee, Debabrata; Abbas, Aamer

    2016-01-01

    Summary Background Myxomatous mitral valve with prolapse are classically seen with abnormal leaflet apposition during contraction of the heart. Hemodynamic disorders can result from eccentric mitral regurgitation usually caused by chordae tendinae rupture or papillary muscle dysfunction. Echocardiography is the gold standard for evaluation of leaflet flail and prolapse due to high sensitivity and specificity. Though most mitral valve prolapse are asymptomatic those that cause severe regurgitation need emergent surgical intervention to prevent disease progression. Case Report We report a 54 year old Hispanic male who presented with progressively worsening dyspnea and palpitations. Initial evaluation was significant for atrial fibrillation on electrocardiogram with subsequent echocardiography revealing myxomatous mitral valve with prolapse. Following surgical repair of the mitral valve, the dyspnea and palpitations resolved. Conclusions Mitral valve prolapse is a common valvular abnormality but the pathogenic cause of myxomatous valves has not been elucidated. Several theories describe multiple superfamilies of proteins to be involved in the process. Proper identification of these severe mitral regurgitation due to these disease valves will help relieve symptomatic mitral valve prolapse patients. PMID:27279924

  15. 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.

  16. Spin-valve phototransistor

    NASA Astrophysics Data System (ADS)

    Huang, Biqin; Altfeder, Igor; Appelbaum, Ian

    2007-01-01

    The spin-valve phototransistor is a semiconductor-ferromagnetic metal multilayer-semiconductor transistor operated by photoexciting hot electrons in the emitter semiconductor into a Schottky collector. This device uses an ultra-high vacuum-bonded float zone Si/multilayer/n-InP structure. To distinguish the emitter interband-excited component of collector current from base/collector internal photoemission, a lock-in spectroscopy sensitive only to the magnetocurrent is used. The experimental results indicate a pathway to improve the magnetocurrent of a related device, the spin-valve photodiode, by increasing the fraction of hot electron current that travels through both layers of the ferromagnetic spin valve and demonstrate that hot electrons photogenerated in one semiconductor can be collected by another through a thin ferromagnetic multilayer.

  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. Huge tricuspid valve abscess.

    PubMed

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

    2009-03-01

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

  19. 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.

  20. 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

  1. Aortic valve surgery - minimally invasive

    MedlinePlus

    ... There are two main types of new valves: Mechanical, made of man-made materials, such as titanium ... Mechanical heart valves do not fail often. However, blood clots can develop on them. If a blood ...

  2. Mitral valve surgery - minimally invasive

    MedlinePlus

    ... There are two main types of new valves: Mechanical, made of man-made materials, such as titanium ... Mechanical heart valves do not fail often. However, blood clots can develop on them. If a blood ...

  3. Heart valve surgery - series (image)

    MedlinePlus

    ... animal donors (porcine: pigs) which are placed in synthetic rings, and artificial valves are made of metal or plastic. Natural valves rarely require life-long medication to prevent blood clot formation (anticoagulation), ...

  4. Inexpensive Pressure-Relief Valve

    NASA Technical Reports Server (NTRS)

    Theordore, E. A.

    1985-01-01

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

  5. 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 ...

  6. 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.

  7. 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.

  8. What Is Heart Valve Disease?

    MedlinePlus

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

  9. Mitral valve surgery - minimally invasive

    MedlinePlus

    ... that does many of these procedures. Minimally invasive heart valve surgery has improved greatly in recent years. These ... WT, Mack MJ. Transcatheter cardiac valve interventions. Surg Clin North Am . 2009;89:951-66. ...

  10. Sticky or Slippery Wetting: Network Formation Conditions Can Provide a One-Way Street for Water Flow on Platinum-cured Silicone.

    PubMed

    Wang, Chenyu; Nair, Sithara S; Veeravalli, Sharon; Moseh, Patricia; Wynne, Kenneth J

    2016-06-01

    -temperature end (slippery surface) but became pinned at the low-temperature end (sticky surface) and did not move when the slide was rotated 180°. The surface was therefore a "one-way street" for water droplet flow. Theory provides fundamental understanding for slippery/sticky behavior for gradient S-PDMS and Pt-PDMS coatings. A model for network formation is based on hydrosilylation at high temperature and condensation curing of Si-OH from autoxidation of Si-H at low temperatures. In summary, network formation conditions strongly affect receding contact angles and water adhesion for Sylgard 184 and the filler-free mimic Pt-PDMS. These findings suggest careful control of curing conditions is important to silicones used in microfluidic devices or as biomedical materials. Network-forming conditions also impact bulk mechanical properties for Sylgard 184, but the range that can be obtained has not been critically examined for specific applications. PMID:27175918

  11. St Jude Medical Portico valve.

    PubMed

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

    2012-09-01

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

  12. 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.

  13. Tide gate valve

    SciTech Connect

    Raftis, S. G.

    1985-01-08

    A tide gate check valve in which at least three converging sides are provided at a tapered region of a flexible sleeve, so that on reverse back pressure build-up of fluid, reverse fluid flow is prevented, while the valve sleeve does not invert or collapse. The present configuration features embedded reinforcing elements for resisting inversion or collapsing when the back pressure builds up. This feature is especially important for large-sized conduits of 36'' or 72'' diameter, or even larger, such as are common in storm sewer applications.

  14. Pressure Relief Valve

    NASA Technical Reports Server (NTRS)

    1985-01-01

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

  15. Examination of a 15. 24-cm ball valve from the Morgantown Energy Technology Center Lock Hopper Valve Testing and Development Project: failure analysis report

    SciTech Connect

    Danyluk, S.; Diercks, D.; Dragel, G.M.

    1980-01-01

    A 15.24-cm ball valve failed while undergoing tests in simulated lock hopper service. The valve stem developed severe torsional deformation after 3134 cycles while handling limestone fines, and a replacement stem also exhibited deformation after an additional 124 cycles. The test was terminated at that point due to excessive valve leakage. Inspection of the valve at METC revealed large quantities of limestone fines packed between the valve ball and the body, and also revealed chipping of the chromium oxide coating around the valve stem slot. The valve seats, ball, and stem were sent to the Materials Science Division of Argonne National Laboratory for further examination. A visual examination at Argonne confirmed the general features seen at METC, and also revealed chipping of the coating on the overspray region of one of the valve seats. It was determined that the torque required to cause gross plastic deformation of the valve stem was well below that which the actuator was capable of applying in the valve test at METC. A microstructural examination of sections from each of the two valve seats indicated no significant debonding of the coating, and an independent analysis by the Linde Division of Union Carbide Corp. found the coating to meet the manufacturer's specifications. Variations in coating thickness on the valve ball of the order of 50% were observed using eddy-current techniques, but absolute values for the coating thicknesses were not obtained.Hardness readings on the valve-seat coating material were found to be slightly below the specified values, but the difference did not appear to be significant.

  16. 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.

  17. Precise-Conductance Valve Insert

    NASA Technical Reports Server (NTRS)

    Outlaw, R. A.; Hoyt, R. F.

    1986-01-01

    Valve modification provides two operating modes fully open and small, precise leak. Copper insert with radially oriented holes allows small, controllable, precise effusion rate when valve closed or nearly unobstructed flow when valve open. Numerous applications in surface physics, vacuum physics, materials science, gas kinetics, thin films, and other areas of research requiring measured flows of gas into or out of system.

  18. 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.

  19. 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.

  20. Lineage and morphogenetic analysis of the cardiac valves.

    PubMed

    de Lange, Frederik J; Moorman, Antoon F M; Anderson, Robert H; Männer, Jörg; Soufan, Alexandre T; de Gier-de Vries, Corrie; Schneider, Michael D; Webb, Sandra; van den Hoff, Maurice J B; Christoffels, Vincent M

    2004-09-17

    We used a genetic lineage-labeling system to establish the material contributions of the progeny of 3 specific cell types to the cardiac valves. Thus, we labeled irreversibly the myocardial (alphaMHC-Cre+), endocardial (Tie2-Cre+), and neural crest (Wnt1-Cre+) cells during development and assessed their eventual contribution to the definitive valvar complexes. The leaflets and tendinous cords of the mitral and tricuspid valves, the atrioventricular fibrous continuity, and the leaflets of the outflow tract valves were all found to be generated from mesenchyme derived from the endocardium, with no substantial contribution from cells of the myocardial and neural crest lineages. Analysis of chicken-quail chimeras revealed absence of any substantial contribution from proepicardially derived cells. Molecular and morphogenetic analysis revealed several new aspects of atrioventricular valvar formation. Marked similarities are seen during the formation of the mural leaflets of the mitral and tricuspid valves. These leaflets form by protrusion and growth of a sheet of atrioventricular myocardium into the ventricular lumen, with subsequent formation of valvar mesenchyme on its surface rather than by delamination of lateral cushions from the ventricular myocardial wall. The myocardial layer is subsequently removed by the process of apoptosis. In contrast, the aortic leaflet of the mitral valve, the septal leaflet of the tricuspid valve, and the atrioventricular fibrous continuity between these valves develop from the mesenchyme of the inferior and superior atrioventricular cushions. The tricuspid septal leaflet then delaminates from the muscular ventricular septum late in development. PMID:15297379

  1. Acute LVOT Obstruction with a Carbomedics Mechanical Valve Prosthesis.

    PubMed

    Alsidawi, Said; Joyce, David L; Malouf, Joseph F; Nkomo, Vuyisile T

    2016-06-01

    A 62-year-old female with severe symptomatic rheumatic mitral stenosis was referred for mitral valve replacement. A 27-mm Carbomedics mechanical mitral valve was placed using everting sutures. As the patient was weaned off cardiopulmonary bypass, she became hemodynamically unstable. Intraoperative transesophageal echocardiogram revealed a significant drop in left ventricular function along with severe LVOT obstruction. The Carbomedics prosthesis was replaced by a 27-mm St. Jude mechanical valve using noneverting sutures which relieved the LVOT obstruction. doi: 10.1111/jocs.12749 (J Card Surg 2016;31:376-379). PMID:27087635

  2. 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.

  3. 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.

  4. Bicuspid aortic valve

    MedlinePlus

    ... is unclear, but it is the most common congenital heart disease . It often runs in families. The bicuspid aortic ... A.M. Editorial team. Related MedlinePlus Health Topics Congenital Heart Defects Heart Valve Diseases Browse the Encyclopedia A.D.A.M., Inc. ...

  5. 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)

  6. 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.

  7. Stennis tests shuttle valves

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Flames burst from the E-1 Test Stand as Stennis Space Center engineers perform one of dozens of shuttle flow valve tests in early February. Stennis engineers teamed with Innovative Partnership Program partners to perform the tests after NASA officials delayed the launch of the STS-119 mission because of concerns with the shuttle part.

  8. Battery vent valve

    SciTech Connect

    McCartney, C.P. Jr.; Montgomery, C.C.; Meadows, C.A.; Cole, B.A.

    1988-10-25

    This patent describes an electric storage battery comprising (1) a container defining a compartment containing gas-generating electro-chemical means for producing an electric current, and (2) check/relief valve means operatively associated with the container upon closing to isolate the electrochemical means from the ambient atmosphere and upon opening to vent the compartment when the internal pressure of the gas generated in the compartment exceeds a predetermined superatmospheric pressure the improvement wherein the valve comprises: a housing defining a vent chamber and including a valve seat projecting into the chamber, the seat having a sloping exterior sealing surface; an inlet in one end of the housing for admitting gas into the chamber from the compartment; means for exhausting the gas from the chamber to the environment; and a sealing member in the chamber circumscribing the inlet for controlling the internal pressures at which the opening and closing occurs and as necessary, for dumping relatively large volumes of the gas without excessive build-up of the internal pressure in the container. The sealing member comprising an annular elastomeric skirt secured at one end and having a tubular portion extending from the one end above the inlet so as to provide an internal annular surface exposed to the internal gas pressure and a sealing edge on the interior of the other end of the tubular portion circumferentially sealing engaging the sloping exterior sealing surface when the valve is closed

  9. Vent Relief Valve Test

    NASA Technical Reports Server (NTRS)

    2008-01-01

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

  10. 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.

  11. Valve selection handbook. Third edition

    SciTech Connect

    Zappe, R.W. )

    1991-01-01

    This book covers the fundamentals of value construction and application, and analyzes the different hazards and requirements of all types of industrial fluid flow situations. This book expands the coverage of pressure relief valves and rupture discs. It includes a new section on damping valve chatter, which is a serious problem in installations such as atomic power plants where valve chatter could have catastrophic consequences to the safety of the plant. There is also new information on performance of spring-loaded pressure relief valves and a closer examination of valve selection with respect to rupture discs and explosion venting.

  12. 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.

  13. "Killer coronary artery" and aortic valve stenosis: A tricky case.

    PubMed

    Nader, Joseph; Labont, Béatris Alina; Houpe, David; Caus, Thierry

    2015-11-01

    Anomalous origin of the left main coronary artery from the right coronary sinus is rarely diagnosed in elderly patients. We report such an anomaly in a 75-year-old lady presenting with chest pain and syncope. Preoperative screening revealed that her aortic valve was moderately stenotic. The patient underwent a successful unroofing procedure combined with aortic valve replacement. The outcome was uncomplicated and the patient remained asymptomatic at one year postoperatively. PMID:24787552

  14. Lactococcus garvieae Endocarditis on a Prosthetic Biological Aortic Valve.

    PubMed

    Tsur, A; Slutzki, T; Flusser, D

    2015-09-01

    Lactococcus garvieae (LG) endocarditis is a rare disease in humans. There are only about 16 reported cases in the world. We report a 76-year-old male patient with LG endocarditis. In depth interview with the patient revealed that 2 weeks prior to admission, he had eaten sushi containing raw fish. Unlike many of the other infections reported, which were on a native mitral valve, our patient's vegetation was on a prosthetic aortic valve. PMID:25295408

  15. 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.

  16. In the era of the valve-in-valve: is transcatheter aortic valve implantation (TAVI) in sutureless valves feasible?

    PubMed Central

    Saia, Francesco; Pellicciari, Giovanni; Phan, Kevin; Ferlito, Marinella; Dall’Ara, Gianni; Di Bartolomeo, Roberto; Marzocchi, Antonio

    2015-01-01

    Sutureless aortic valve implantation has emerged as an innovative alternative for treatment of aortic stenosis. By avoiding the placement of sutures, this approach aims to improve surgical outcomes by facilitating less traumatic minimally invasive approaches and reducing cross-clamp and cardiopulmonary bypass duration. However, the absence of sutures may have detrimental effects after sutureless interventions, including paravalvular leakages, valve dislocation, and stent-infolding. Transcatheter aortic valve-in-valve implantation (A-ViV) is emerging as a valuable procedure in patients with dysfunctioning biological aortic valves who are deemed inoperable with conventional surgery. Here we present the first-in-man case of trans-femoral implant of a balloon expandable aortic valve in a leaking sutureless self-expandable valve. PMID:25870827

  17. In the era of the valve-in-valve: is transcatheter aortic valve implantation (TAVI) in sutureless valves feasible?

    PubMed

    Di Eusanio, Marco; Saia, Francesco; Pellicciari, Giovanni; Phan, Kevin; Ferlito, Marinella; Dall'Ara, Gianni; Di Bartolomeo, Roberto; Marzocchi, Antonio

    2015-03-01

    Sutureless aortic valve implantation has emerged as an innovative alternative for treatment of aortic stenosis. By avoiding the placement of sutures, this approach aims to improve surgical outcomes by facilitating less traumatic minimally invasive approaches and reducing cross-clamp and cardiopulmonary bypass duration. However, the absence of sutures may have detrimental effects after sutureless interventions, including paravalvular leakages, valve dislocation, and stent-infolding. Transcatheter aortic valve-in-valve implantation (A-ViV) is emerging as a valuable procedure in patients with dysfunctioning biological aortic valves who are deemed inoperable with conventional surgery. Here we present the first-in-man case of trans-femoral implant of a balloon expandable aortic valve in a leaking sutureless self-expandable valve. PMID:25870827

  18. Measurement of reed valve kinematics

    NASA Astrophysics Data System (ADS)

    Fenkl, Michael; Dvořák, Václav; Vít, Tomáš

    2016-03-01

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

  19. 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.

  20. 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.

  1. Postpartum valve thrombosis: a happy ending thriller.

    PubMed

    Bollati, Mario; Moretti, Claudio; Sciuto, Filippo; Omedè, PierLuigi; Marra, Walter Grosso; Morello, Mara; Grimaldi, Roberto; Rabbia, Claudio; Zoccai, Giuseppe Biondi; Sheiban, Imad

    2015-01-01

    A 29-year-old woman with two mechanical valve prostheses was referred to our institution for sudden and self-resolved diplopia 2 weeks after childbirth. From the beginning of pregnancy, nadroparin was started instead of warfarin. The echocardiogram performed at hospital admission revealed a severe aortic prosthesis regurgitation due to incomplete leaflet apposition with a prosthetic aortic transvalvular gradient increase. Three-dimensional transoesophageal echocardiography revealed a thrombus located between the two prostheses, causing intermittent aortic valve malfunction. Intravenous heparin was started. Three days later, a second transoesophageal echocardiogram revealed a decreased aortic transvalvular gradient, but an oval thrombus adhered to the mitral prosthesis and fluctuating through the prosthetic valve was detected. Tissue plasminogen activator infusion was started. To reduce cerebral embolization, carotid filters used during artery angioplasty were placed in common carotid arteries, left and right. No complication occurred during and after the procedure. With thrombus absence at 30-min transoesophageal echocardiography, filters were removed. The patient continued intravenous heparin until achievement of a therapeutic international normalized ratio range and she was asymptomatic on discharge. PMID:21157367

  2. 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.

  3. Percutaneous Pulmonary Valve Implantation

    PubMed Central

    Lee, Hyoung-Doo

    2012-01-01

    Pulmonary regurgitation (PR) is a frequent sequelae after repair of tetralogy of Fallot, pulmonary atresia, truncus arteriosus, Rastelli and Ross operation. Due to patient growth and conduit degeneration, these conduits have to be changed frequently due to regurgitation or stenosis. However, morbidity is significant in these repeated operations. To prolong conduit longevity, bare-metal stenting in the right ventricular outflow tract (RVOT) obstruction has been performed. Stenting the RVOT can reduce the right ventricular pressure and symptomatic improvement, but it causes PR with detrimental effects on the right ventricle function and risks of arrhythmia. Percutaneous pulmonary valve implantation has been shown to be a safe and effective treatment for patients with pulmonary valve insufficiency, or stenotic RVOTs. PMID:23170091

  4. Cells need safety valves.

    PubMed

    Danchin, Antoine

    2009-07-01

    In Escherichia coli, the role of lacA, the third gene of the lactose operon, has remained an enigma. I suggest that its role is the consequence of the need for cells to have safety valves that protect them from the osmotic effect created by their permeases. Safety valves allow them to cope with the buildup of osmotic pressure under accidental transient conditions. Multidrug resistance (MDR) efflux, thus named because of our anthropocentrism, is ubiquitous. Yet, the formation of simple leaks would result in futile influx/efflux cycles. Versatile modification enzymes with low sensitivity solve the problem if the modified metabolite is the one exported by MDR permeases. This may account for the pervasive presence of acetyltransferases, such as LacA, associated to acetyl-metabolite exporters. This scenario of constraints imposed by efficient influx of metabolites provides us with a model that should be followed when constructing synthetic cells. PMID:19472369

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Aortic valve decalcification revisited.

    PubMed

    Marty, A T; Mufti, S; Murabit, I

    1989-11-01

    A 75-year-old woman with a small calcified aortic root, severe aortic stenosis and triple vessel coronary artery disease developed angina at rest. Aortic valve decalcification and quadruple aorto-coronary bypass were done as her aortic root was too small and calcified to do anything else. Postoperative clinical and hemodynamic results have been excellent. Literature review supports application of this therapy in selected patients with trileaflet senescent aortic stenosis. PMID:2614067

  11. Gas flow control valve

    SciTech Connect

    Phlipot, J.R.; Pinkston, S.R.; Nurre, H.

    1988-02-09

    A compact gas flow control valve is described comprising a valve body having a first, rotor cavity-defining portion and a second cover portion covering the rotor cavity, at least one of the body portions including inlet means communicating with the rotor chamber for receiving gas under pressure for providing the gas to the rotor chamber, at least one of the body portions including outlet means for delivery of the gas by the flow control valve, a rotor within the rotor cavity, the rotor including a flat surface, a flow control plate carried by the rotor, the flow control plate covering and lying against the flat surface of the rotor, the rotor having ports opening through the rotor surface, the ports being of sufficiently large size as not to limit the flow of the gas therethrough. The flow control plate comprises a thin, flat metal disc provided with gas flow control orifices extending therethrough and spaced circumferentially around the disc and in registry with respective ones of the ports, the rotor being of substantially greater thickness than the disc, the gas flow control being of different sizes and passage means for providing communication between the outlet means and at least a selected one of the flow control plate origices, selector means for orienting the rotor to permit flow only through selected flow control plate orifices and a corresponding rotor port for delivery by the outlet means.

  12. Controlled PCV valve

    SciTech Connect

    Zeigler, T.W. Jr.; Romanczuk, C.S.; Betterton, J.T.; Glover, A.H.

    1987-08-18

    A positive crankcase ventilation control device is described for use with an internal combustion engine and, specifically, for controlling the flow of emission laden vaporous fluids from the crankcase thereof, the control device including selective power means for substantially increasing the flow of emission laden air through the device, comprising: a generally hollow housing with an inlet forming portion adapted to be fluidly connected to the interior spaces of an internal combustion engine to receive emission laden air therefrom; the housing having an outlet forming device adapted to be fluidly connected to the air and fuel inletting portion of the internal combustion engine for disposing of the emission laden air from the engine, the inlet and outlet portions being connected within the interior of the housing by a flow control passage of specific flow area; an elongated valve plug member within the housing and having an end portion with a conically tapered configuration adapted to move progressively into the aforesaid flow control passage thereby decreasing the flow area thereof and, consequently, the total flow through the device; yieldable means urging the elongated valve member toward a position ensuring maximum flow through the flow control passage, but being yieldable to allow the valve member to move so that the conically tapered portion progressively extends further into the flow control passage to thereby decrease the flow area.

  13. 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.

  14. 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.

  15. Actuator-valve interface optimization. [Explosive actuators

    SciTech Connect

    Burchett, O.L.; Jones, R.L.

    1987-02-01

    The interface of explosive actuator driven valves can be optimized to maximize the velocity of the valve plunger by using the computer code Actuator-Valve Response. Details of the AVR model of the actuator driven valve plunger and the results of optimizing an actuator-valve interface with AVR are presented. 5 refs., 5 figs., 3 tabs.

  16. Solenoid Valve With Self-Compensation

    NASA Technical Reports Server (NTRS)

    Woeller, Fritz H.; Matsumoto, Yutaka

    1987-01-01

    New solenoid-operated miniature shutoff valve provides self-compensation of differential pressure forces that cause jamming or insufficient valve closure as in single-seal valves. Dual-seal valve is bidirectional. Valve simultaneously seals both inlet and outlet tubes by pressing single disk of silicone rubber against ends of both.

  17. 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

  18. Self-compensating solenoid valve

    NASA Technical Reports Server (NTRS)

    Woeller, Fritz H. (Inventor); Matsumoto, Yutaka (Inventor)

    1987-01-01

    A solenoid valve is described in which both an inlet and an outlet of the valve are sealed when the valve is closed. This double seal compensates for leakage at either the inlet or the outlet by making the other seal more effective in response to the leakage and allows the reversal of the flow direction by simply switching the inlet and outlet connections. The solenoid valve has a valve chamber within the valve body. Inlet and outlet tubes extend through a plate into the chamber. A movable core in the chamber extends into the solenoid coil. The distal end of the core has a silicone rubber plug. Other than when the solenoid is energized, the compressed spring biases the core downward so that the surface of the plug is in sealing engagement with the ends of the tubes. A leak at either end increases the pressure in the chamber, resulting in increased sealing force of the plug.

  19. Update of transcatheter valve treatment

    PubMed Central

    Liu, Xian-bao; Wang, Jian-an

    2013-01-01

    Transcatheter valve implantation or repair has been a very promising approach for the treatment of valvular heart diseases since transcatheter aortic valve implantation (TAVI) was successfully performed in 2002. Great achievements have been made in this field (especially TAVI and transcatheter mitral valve repair—MitraClip system) in recent years. Evidence from clinical trials or registry studies has proved that transcatheter valve treatment for valvular heart diseases is safe and effective in surgical high-risk or inoperable patients. As the evidence accumulates, transcatheter valve treatment might be an alterative surgery for younger patients with surgically low or intermediate risk valvular heart diseases in the near future. In this paper, the updates on transcatheter valve treatment are reviewed. PMID:23897785

  20. WUnicuspid Aortic Valve- An Uncommon Anomaly With a Common Presentation.

    PubMed

    Sitwala, Puja; Abusara, Ashraf; Ladia, Vatsal; Ladia, Vatsal; Panchal, Hemang B; Raudat, Charles; Paul, Timir K

    2016-01-01

    Unicuspid aortic valve (UAV), which is a rare congenital anomaly, usually presents as aortic stenosis and/or aortic regurgitation. Here we present a case of UAV co-existent with an ascending aortic aneurysm. A 26-year-old male with no significant past medical history presented to the hospital after two episodes of syncope. Transthoracic echocardiogram showed an ejection fraction of 62%, severely stenotic aortic valve, and moderate aortic regurgitation. Computed tomography revealed calcification of the aortic valve, compatible with aortic stenosis and aneurysm of the ascending aorta measuring 4.3 cm in diameter. He underwent successful aortic valve replacement and repair of ascending aortic aneurysm. He recovered well without any complications. This case suggests that any young patient who presents with syncope, aortic stenosis would be a differential and further workup by any available non-invasive modality needs to be performed. PMID:27383857

  1. 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.

  2. 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.

  3. Mitral valve repair versus replacement

    PubMed Central

    Keshavamurthy, Suresh; Gillinov, A. Marc

    2015-01-01

    Degenerative, ischemic, rheumatic and infectious (endocarditis) processes are responsible for mitral valve disease in adults. Mitral valve repair has been widely regarded as the optimal surgical procedure to treat mitral valve dysfunction of all etiologies. The supporting evidence for repair over replacement is strongest in degenerative mitral regurgitation. The aim of the present review is to summarize the data in each category of mitral insufficiency and to provide recommendations based upon this data. PMID:26309824

  4. 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.

  5. 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.

  6. There's more than one way to build a caldera magma chamber: Evidence from volcanic-plutonic relationships at three faulted Rio-Grande-rift calderas

    NASA Astrophysics Data System (ADS)

    Zimmerer, M. J.; McIntosh, W. C.

    2011-12-01

    The temporal and chemical relationships of volcanic and plutonic rocks of the Questa (NM), Mt. Aetna (CO), and Organ caldera (NM) complexes were investigated to establish the origin of these silicic magmas. Rio Grande Rift faulting at these systems has exposed both intracaldera sequences and subvolcanic plutons. Ar/Ar and U/Pb ages reveal the timing of volcanic activity and pluton emplacement and cooling. We observe a link between ignimbrite zoning patterns and the temporal-chemical relationship of volcanic and plutonic rocks. The Questa caldera erupted the high-SiO2 peralkaline Amalia Tuff (AT) at 25.4 Ma. Volumetrically minor phases of two resurgent plutons and a ring dike are compositionally similar to the AT. The age of the ring dike (25.4 Ma) is indistinguishable to AT, suggesting that the peralkaline intrusions are nonerupted AT. The remaining pluton ages are 100 ka to 6.1 Ma younger than AT and are too young to be the AT residual crystal mush. The Mt. Princeton batholith and nested Mt. Aetna caldera are interpreted to be the sources for the 37.3 Ma, low-SiO2 rhyolitic Wall Mountain Tuff (WMT) and the 34.3 Ma, dacitic Badger Creek Tuff (BCT). U/Pb and Ar/Ar ages of Mt. Princeton batholith (36.5 to 35.1 Ma) indicate that it was emplaced and rapidly cooled during the interval between the WMT and BCT eruptions, and that any WMT age intrusions are now eroded. During the eruption of the BCT, the fully crystallized Mt. Princeton batholith collapsed into the Mt. Aetna caldera. Intrusions along the margins of the Mt. Aetna caldera are compositionally identical the BCT and contain zircons 100 to 500 ka older than the tuff, suggesting that the BCT magma chamber was incrementally emplaced prior to caldera eruption. The Organ caldera complex erupted three ignimbrites: a basal high-silica 36.5 Ma rhyolite, a middle intermediate-silica 36.2 Ma rhyolite, and an upper 36.0 Ma low-silica rhyolite. The intracaldera sequence is intruded by the Organ Needle pluton. U/Pb zircon

  7. 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.

  8. 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.

  9. 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.

  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. Valve-in-Valve-in-Valve Transcatheter Aortic Valve Implantation to Treat a Degenerated Surgical Bioprosthesis in a Subaortic Position

    PubMed Central

    Nuis, Rutger-Jan; Benitez, Luis M.; Nader, Carlos A.; Perez, Sergio; de Marchena, Eduardo J.; Dager, Antonio E.

    2013-01-01

    Transcatheter aortic valve implantation for aortic stenosis has evolved as an alternative treatment for patients who are at high or excessive surgical risk. We report the case of an 84-year-old man with a degenerated surgically implanted valve in a subaortic position (9 mm below the native annulus) who underwent “valve-in-valve” transcatheter aortic valve implantation with use of a Medtronic CoreValve system. We planned to deploy the CoreValve at a conventional depth in the left ventricular outflow tract; we realized that this might result in paravalvular regurgitation, but it would also afford a “deep” landing site for a second valve, if necessary. Ultimately, we implanted a second CoreValve deep in the left ventricular outflow tract to seal a paravalvular leak. The frame of the first valve—positioned at the conventional depth—enabled secure anchoring of the second valve in a deeper position, which in turn effected successful treatment of the failing subaortic surgical prosthesis without paravalvular regurgitation. PMID:23914032

  12. Tomographic PIV behind a prosthetic heart valve

    NASA Astrophysics Data System (ADS)

    Hasler, D.; Landolt, A.; Obrist, D.

    2016-05-01

    The instantaneous three-dimensional velocity field past a bioprosthetic heart valve was measured using tomographic particle image velocimetry. Two digital cameras were used together with a mirror setup to record PIV images from four different angles. Measurements were conducted in a transparent silicone phantom with a simplified geometry of the aortic root. The refraction indices of the silicone phantom and the working fluid were matched to minimize optical distortion from the flow field to the cameras. The silicone phantom of the aorta was integrated in a flow loop driven by a piston pump. Measurements were conducted for steady and pulsatile flow conditions. Results of the instantaneous, ensemble and phase-averaged flow field are presented. The three-dimensional velocity field reveals a flow topology, which can be related to features of the aortic valve prosthesis.

  13. How Is Mitral Valve Prolapse Diagnosed?

    MedlinePlus

    ... page from the NHLBI on Twitter. How Is Mitral Valve Prolapse Diagnosed? Mitral valve prolapse (MVP) most often is detected during a ... a clicking sound as they shut. If the mitral valve is leaking blood back into the left atrium, ...

  14. Whitey Gauge and Root Valves (VPS)

    SciTech Connect

    MISKA, C.

    2000-09-03

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

  15. Low energy high pressure miniature screw valve

    DOEpatents

    Fischer, Gary J.; Spletzer, Barry L.

    2006-12-12

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

  16. Chatter-free check valve - A concept

    NASA Technical Reports Server (NTRS)

    Dunbar, J. E.

    1971-01-01

    Valve head moves in spiral motion away from seat. Motion is controlled by travel of pin along spiral groove in valve guide. Clearances between pin and groove permit free motion of valve, but effectively dampen vibration and chattering.

  17. When a Heart Murmur Signals Valve Disease

    MedlinePlus

    ... in adults may be related to: Valve calcification Endocarditis Rheumatic fever In children, abnormal heart murmurs may ... Problem: Pulmonary Valve Regurgitation Heart Valves and Infective Endocarditis • Risks, Signs and Symptoms • Accurate Diagnosis • Treatment Options • ...

  18. 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.

  19. Valve-in-valve transcatheter aortic valve implantation: the new playground for prosthesis-patient mismatch.

    PubMed

    Faerber, Gloria; Schleger, Simone; Diab, Mahmoud; Breuer, Martin; Figulla, Hans R; Eichinger, Walter B; Doenst, Torsten

    2014-06-01

    Transcatheter aortic valve implantation (TAVI) has become an established procedure for patients with aortic valve stenosis and significant comorbidities. One option offered by this technique is the implantation of a transcatheter valve inside a surgically implanted bioprosthesis. Many reports address the feasibility but also the pitfalls of these valve-in-valve (VIV) procedures. Review articles provide tables listing which valve sizes are appropriate based on the size of the initially implanted bioprosthesis. However, we previously argued that the hemodynamic performance of a prosthetic tissue valve is in large part a result of the dimensions of the bioprosthesis in relation to the patient's aortic outflow dimensions. Thus, the decision if a VIV TAVI procedure is likely to be associated with a favorable hemodynamic result cannot safely be made by looking at premade sizing tables that do not include patient dimensions and do not inquire about the primary cause for bioprosthetic valve stenosis. Prosthesis-patient mismatch (PPM) may therefore be more frequent than expected after conventional aortic valve replacement. Importantly, it may be masked by a potentially flawed method assessing its relevance. Such PPM may therefore impact significantly on hemodynamic outcome after VIV TAVI. Fifteen percent of currently published VIV procedures show only a minimal reduction of pressure gradients. We will address potential pitfalls in the current determination of PPM, outline the missing links for reliable determination of PPM, and present a simplified algorithm to guide decision making for VIV TAVI. PMID:24612128

  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. 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. PMID:27549545

  3. 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.

  4. Valve dynamic and thermal cycle model in stepless capacity regulation for reciprocating compressor

    NASA Astrophysics Data System (ADS)

    Jin, Jiangming; Hong, Weirong

    2012-11-01

    The existing researches of stepless capacity regulation system by depressing the suction valve for reciprocation compressor always adopt hypothesis that the compressor valves are open or close instantaneously, the valve dynamic has not been taken account into thermal cycle computation, the influence of capacity regulation system on suction valves dynamic performance and cylinder thermal cycle operation has not been considered. This paper focuses on theoretical and experimental analysis of the valve dynamic and thermal cycle for reciprocating compressor in the situation of stepless capacity regulation. The valve dynamics equation, gas forces for normal and back flow, and the cylinder pressure varying with suction valve unloader moment during compression thermal cycle are discussed. A new valve dynamic model based on L-K real gas state equation for reciprocating compressor is first deduced to reduce the calculation errors induced by the ideal gas state equation. The variations of valve dynamic and cylinder pressure during part of compression stroke are calculated numerically. The calculation results reveal the non-normal thermal cycle and operation condition of compressor in stepless capacity regulation situation. The numerical simulation results of the valve dynamic and thermal cycle parameters are also verified by the stepless capacity regulation experiments in the type of 3L-10-8 reciprocating compressor. The experimental results agree with the numerical simulation results, which show that the theoretical models proposed are effective and high-precision. The proposed theoretical models build the theoretical foundation to design the real stepless capacity regulation system.

  5. 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.

  6. Valve replacement at Calvert Cliffs

    SciTech Connect

    Sponsel, J.R.; Boone, K.R.; Simpson, A.L.

    1994-01-01

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

  7. 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)

  8. 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.

  9. 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.

  10. Improved Photosensor for Light Valves

    NASA Technical Reports Server (NTRS)

    Koda, N. J.

    1983-01-01

    Processing changes improve performance of liquid-crystal light valve for displaying projection TV images. New approach monitors performance of finished light valves for given changes in CdS process and experimentally to optimize process for good sensitivity and low negative memory.

  11. 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.

  12. One Way--Frustrating, but Rewarding!

    ERIC Educational Resources Information Center

    Yencer, Dick

    1979-01-01

    Describes the experiences of a vocational agriculture teacher who worked for four years with rice farmers in Indonesia. Suggests reasons why changes in farming practices are hard to bring about in developing nations. (LRA)

  13. Threading One's Way Through the Geographic Region.

    ERIC Educational Resources Information Center

    Thomas, Paul F.

    1982-01-01

    Designed for students in grades 7 through 12, the paper presents illustrative resource materials for teaching concepts related to geographic regions. Emphasis is on giving students an understanding of the interrelationship between regional characteristics and human behavior. The paper introduces students to the following notions: environmental…

  14. Development and application of a diagnostic system for electrically driven valves

    NASA Astrophysics Data System (ADS)

    Finkel', B. M.; Matveev, A. V.; Golovlev, V. V.; Ryazanova, M. G.; Yaryshev, A. B.

    2010-05-01

    We briefly describe the system for diagnosing electrically driven valves that was developed jointly at the All-Russia Institute for Nuclear Power Plant Research and ZAO Diaprom, and which is being put in operation at many Russian nuclear power stations for revealing a wide spectrum of malfunctions that may occur in valves and their drives.

  15. Perioperative management of patient with Bombay blood group undergoing mitral valve replacement.

    PubMed

    Priye, Shio; Sathyanarayan, J; Shivaprakash, S; Reddy, Durgaprasad

    2015-12-01

    Bombay red blood cell phenotype is an extremely rare blood type for which patients can receive only autologous or Bombay phenotype red blood cells. We report a case of stenotic mitral valve with Bombay phenotype who underwent minimal invasive right lateral thoracotomy for the replacement of the mitral valve. A male patient from Bangladesh presented to the hospital with New York Heart Association III symptoms. His medical evaluation revealed severe mitral valve stenosis and mild aortic valve regurgitation. The patient received erythropoietin, intravenous iron succinate and folic acid tablets. Autologous blood transfusion was carried out. The mitral valve was replaced with a prosthetic valve successfully. After weaning off from cardiopulmonary bypass, heparinisation was corrected with protamine. Post-operatively, the patient received autologous red blood cells. The patient recovered after 1-day of inotropic support with adrenaline and milrinone, and diuretics and was discharged on the 5(th) post-operative day. PMID:26903676

  16. Perioperative management of patient with Bombay blood group undergoing mitral valve replacement

    PubMed Central

    Priye, Shio; Sathyanarayan, J; Shivaprakash, S; Reddy, Durgaprasad

    2015-01-01

    Bombay red blood cell phenotype is an extremely rare blood type for which patients can receive only autologous or Bombay phenotype red blood cells. We report a case of stenotic mitral valve with Bombay phenotype who underwent minimal invasive right lateral thoracotomy for the replacement of the mitral valve. A male patient from Bangladesh presented to the hospital with New York Heart Association III symptoms. His medical evaluation revealed severe mitral valve stenosis and mild aortic valve regurgitation. The patient received erythropoietin, intravenous iron succinate and folic acid tablets. Autologous blood transfusion was carried out. The mitral valve was replaced with a prosthetic valve successfully. After weaning off from cardiopulmonary bypass, heparinisation was corrected with protamine. Post-operatively, the patient received autologous red blood cells. The patient recovered after 1-day of inotropic support with adrenaline and milrinone, and diuretics and was discharged on the 5th post-operative day. PMID:26903676

  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. Mitral valve-in-valve and valve-in-ring for failing surgical bioprosthetic valves and rings.

    PubMed

    Ghosh-Dastidar, Michael; Narayana, Ashok; Boix, Ricardo; Bapat, Vinayak

    2016-06-01

    The transcatheter valve-in-valve (VIV) procedure for failed aortic bioprostheses is recognized as an alternative treatment to conventional surgery in high-risk patients. This less invasive option has now been applied to failed mitral bioprostheses (VIV) or failed repairs i.e. valve-in-ring (VIR). In this emerging field, to get an optimal result, a good understanding of the design features of the failed surgical heart valve/ring, the transcatheter heart valve being used and their compatibility, is of paramount importance. Although similar in many ways to the aortic counterpart, a mitral VIV/VIR procedure can pose certain different challenges such as delayed migration and left ventricular outflow tract obstruction. This review describes the features of bioprostheses, rings and THVs relevant to a VIV/VIR procedure, and also provides guidance regarding sizing, positioning and how to avoid some of the major complications therefore improving the chances of a successful outcome. PMID:26923547

  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. High pressure gate valve failure

    SciTech Connect

    Place, M. Jr.; Kochera, J.W.

    1995-10-01

    Shell Oil Company was attempting to develop CRA (Corrosion Resistant Alloy) valves for use in those completions utilizing CRA tubing. The testing and development of new materials for CRA valves of both the solid and clad version were pursued. As part of this CRA valve development program, Shell Oil Company tried to reconcile the apparent discrepancy between unacceptable laboratory test results on 410 SS in sour environments with both the apparent success (when properly heat treated and at an acceptable hardness level) of this alloy in commercial sour use and the fact that it is fully accepted in NACE MR-01-75. A410 stainless steel valve was tested near the material yield strength at low H{sub 2}S partial pressures at the STF (Static Test Facility) in Mississippi. The valve failed by crack growth and body wall leakage while under test.

  1. Elevated transaortic valvular gradients after combined aortic valve and mitral valve replacement: an intraoperative dilemma.

    PubMed

    Essandoh, Michael; Portillo, Juan; Zuleta-Alarcon, Alix; Castellon-Larios, Karina; Otey, Andrew; Sai-Sudhakar, Chittoor B

    2015-03-01

    High transaortic valvular gradients, after combined aortic valve and mitral valve replacement, require prompt intraoperative diagnosis and appropriate management. The presence of high transaortic valvular gradients after cardiopulmonary bypass, in this setting, can be secondary to the following conditions: prosthesis dysfunction, left ventricular outflow tract obstruction, supravalvular obstruction, prosthesis-patient mismatch, hyperkinetic left ventricle from administration of inotropes, left ventricular intracavitary gradients, pressure recovery phenomenon, and increased transvalvular blood flow resulting from hyperdynamic circulation or anemia. Transesophageal echocardiography is an extremely useful tool for timely diagnosis and treatment of this complication. We describe a case of a critically ill patient with endocarditis and acute lung injury, who presented for combined aortic valve and mitral valve replacement. Transesophageal echocardiographic assessment, post-cardiopulmonary bypass, revealed high transaortic valvular gradients due to encroachment of the mitral prosthesis strut on the left ventricular outflow tract, which was compounded by a small, hypertrophied, and hyperkinetic left ventricle. Discontinuation of inotropic support, administration of fluids, phenylephrine, and esmolol led to resolution of the high gradients and prevented further surgery. PMID:25549635

  2. A Novel Technique for Experimental Flow Visualization of Mechanical Valves.

    PubMed

    Huang Zhang, Pablo S; Dalal, Alex R; Kresh, J Yasha; Laub, Glenn W

    2016-01-01

    The geometry of the hinge region in mechanical heart valves has been postulated to play an important role in the development of thromboembolic events (TEs). This study describes a novel technique developed to visualize washout characteristics in mechanical valve hinge areas. A dairy-based colloidal suspension (DBCS) was used as a high-contrast tracer. It was introduced directly into the hinge-containing sections of two commercially available valves mounted in laser-milled fluidic channels and subsequently washed out at several flow rates. Time-lapse images were analyzed to determine the average washout rate and generate intensity topography maps of the DBCS clearance. As flow increased, washout improved and clearance times were shorter in all cases. Significantly different washout rate time constants were observed between valves, average >40% faster clearance (p < 0.01). The topographic maps revealed that each valve had a characteristic pattern of washout. The technique proved reproducible with a maximum recorded standard error of mean (SEM) of ±3.9. Although the experimental washout dynamics have yet to be correlated with in vivo visualization studies, the methodology may help identify key flow features influencing TEs. This visualization methodology can be a useful tool to help evaluate stagnation zones in new and existing heart valve hinge designs. PMID:26554553

  3. Effect of valve design on the stent internal diameter of a bioprosthetic valve: a concept of true internal diameter and its implications for the valve-in-valve procedure.

    PubMed

    Bapat, Vinayak N; Attia, Rizwan; Thomas, Martyn

    2014-02-01

    The goal of this study was to provide a measurement of the true internal diameter (ID) of various surgical heart valves (SHV) to facilitate the valve-in-valve (VIV) procedure. During a VIV procedure, it is important to choose the right of the transcatheter heart valve (THV). Most users use the stent ID of an SHV to select the appropriate THV size. Echocardiography and computed tomography measurements are not yet standardized for measuring the ID of a variety of SHVs. Hence, we measured the true ID of SHV to assess the effect of valve design on the stent ID. Thirteen types of stented and 3 types of stentless valves were evaluated. True ID measurements were obtained using calipers and Hegar dilators. These were compared with the stent ID measurements. Fluoroscopy was used to confirm the impact of SHV designs on the true ID. Caliper measurements were found to be inaccurate and are hence not recommended. Hegar dilator measurements revealed a trend of reduction in stent ID. Porcine valves were most affected by their design, with reduction in the stent ID by at least 2 mm; pericardial valves with leaflets sutured inside the stent had the stent ID reduced by at least 1 mm, and SHV with leaflets sutured outside the stent had no effect on stent ID. In the majority of SHV designs, there is a reduction in the stent ID as a result of leaflet tissue. This is important in borderline sizes to avoid problems associated with oversizing and also to confirm suitability for the VIV procedure in the smaller label sizes of SHV. PMID:24440016

  4. 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

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

    PubMed

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

    2015-01-01

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

  6. Minimally invasive aortic valve surgery.

    PubMed

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

    2016-09-01

    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

  7. Aortic valve allografts in sheep

    PubMed Central

    Borrie, John; Hill, G. L.

    1968-01-01

    Some of the mechnical and biological problems surrounding the use of fresh allograft inverted aortic valves as mitral valve substitutes are described. Certain aspects of the problem have been studied experimentally. In three sheep `fresh' aortic valve allografts were inserted, using cardiopulmonary bypass, into the main pulmonary artery, and were observed from 5 to 7 months after operation. The animals survived normally. Their normal pulmonary valves remained in situ. The technique is described. At subsequent necropsy, macroscopically the valves were found to be free from vegetation, and the cusps were pliable and apparently normal. Microscopically, the supporting allograft myocardium showed necrosis and early calcification. The valve cusp showed hyalinization of collagen, although beneath the endocardium this hyalinized collagen contained moderate numbers of fibroblasts with no evidence of proliferation. The endocardium and arterial intima of the allograft showed evidence of ingrowth from adjacent normal host endocardial tissues. The allograft itself was invested in a loose layer of fibro-fatty tissue, which, in view of the necrotic state of the graft myocardium, could well have been a reparative reaction rather than a homograft reaction. It is concluded that, although the cusps could function normally, the necrosis of the myocardium might in time lead to late failure of the graft. Further studies with the valve inserted at mitral level are indicated. Images PMID:5656757

  8. 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.

  9. Valve for controlling solids flow

    DOEpatents

    Feldman, David K.

    1980-01-01

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

  10. 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

  11. Elastogenesis at the onset of human cardiac valve development

    PubMed Central

    Votteler, Miriam; Berrio, Daniel A. Carvajal; Horke, Alexander; Sabatier, Laetitia; Reinhardt, Dieter P.; Nsair, Ali; Aikawa, Elena; Schenke-Layland, Katja

    2013-01-01

    Semilunar valve leaflets have a well-described trilaminar histoarchitecture, with a sophisticated elastic fiber network. It was previously proposed that elastin-containing fibers play a subordinate role in early human cardiac valve development; however, this assumption was based on data obtained from mouse models and human second and third trimester tissues. Here, we systematically analyzed tissues from human fetal first (4-12 weeks) and second (13-18 weeks) trimester, adolescent (14-19 years) and adult (50-55 years) hearts to monitor the temporal and spatial distribution of elastic fibers, focusing on semilunar valves. Global expression analyses revealed that the transcription of genes essential for elastic fiber formation starts early within the first trimester. These data were confirmed by quantitative PCR and immunohistochemistry employing antibodies that recognize fibronectin, fibrillin 1, 2 and 3, EMILIN1 and fibulin 4 and 5, which were all expressed at the onset of cardiac cushion formation (~week 4 of development). Tropoelastin/elastin protein expression was first detectable in leaflets of 7-week hearts. We revealed that immature elastic fibers are organized in early human cardiovascular development and that mature elastin-containing fibers first evolve in semilunar valves when blood pressure and heartbeat accelerate. Our findings provide a conceptual framework with the potential to offer novel insights into human cardiac valve development and disease. PMID:23637335

  12. 42 CFR 84.137 - Inhalation and exhalation valves; check valves; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Inhalation and exhalation valves; check valves... PROTECTIVE DEVICES Supplied-Air Respirators § 84.137 Inhalation and exhalation valves; check valves; minimum requirements. (a) Inhalation and exhalation valves shall be provided where necessary and protected...

  13. 42 CFR 84.137 - Inhalation and exhalation valves; check valves; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  14. 49 CFR 192.145 - Valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...-temperature ratings contained in those requirements. (b) Each cast iron and plastic valve must comply with the... the maximum service temperature. (2) The valve must be tested as part of the manufacturing, as follows...) Each valve must be able to meet the anticipated operating conditions. (d) No valve having shell...

  15. 49 CFR 192.145 - Valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-temperature ratings contained in those requirements. (b) Each cast iron and plastic valve must comply with the... the maximum service temperature. (2) The valve must be tested as part of the manufacturing, as follows...) Each valve must be able to meet the anticipated operating conditions. (d) No valve having shell...

  16. 49 CFR 192.145 - Valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...-temperature ratings contained in those requirements. (b) Each cast iron and plastic valve must comply with the... the maximum service temperature. (2) The valve must be tested as part of the manufacturing, as follows...) Each valve must be able to meet the anticipated operating conditions. (d) No valve having shell...

  17. 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,...

  18. 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,...

  19. 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,...

  20. 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,...

  1. 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,...

  2. 49 CFR 195.116 - Valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Valves. 195.116 Section 195.116 Transportation... PIPELINE Design Requirements § 195.116 Valves. Each valve installed in a pipeline system must comply with the following: (a) The valve must be of a sound engineering design. (b) Materials subject to...

  3. 49 CFR 195.116 - Valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Valves. 195.116 Section 195.116 Transportation... PIPELINE Design Requirements § 195.116 Valves. Each valve installed in a pipeline system must comply with the following: (a) The valve must be of a sound engineering design. (b) Materials subject to...

  4. 49 CFR 195.116 - Valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Valves. 195.116 Section 195.116 Transportation... PIPELINE Design Requirements § 195.116 Valves. Each valve installed in a pipeline system must comply with the following: (a) The valve must be of a sound engineering design. (b) Materials subject to...

  5. 49 CFR 195.420 - Valve maintenance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Valve maintenance. 195.420 Section 195.420... PIPELINE Operation and Maintenance § 195.420 Valve maintenance. (a) Each operator shall maintain each valve..., inspect each mainline valve to determine that it is functioning properly. (c) Each operator shall...

  6. 49 CFR 195.116 - Valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  7. 49 CFR 195.420 - Valve maintenance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Valve maintenance. 195.420 Section 195.420... PIPELINE Operation and Maintenance § 195.420 Valve maintenance. (a) Each operator shall maintain each valve..., inspect each mainline valve to determine that it is functioning properly. (c) Each operator shall...

  8. 49 CFR 195.420 - Valve maintenance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Valve maintenance. 195.420 Section 195.420... PIPELINE Operation and Maintenance § 195.420 Valve maintenance. (a) Each operator shall maintain each valve..., inspect each mainline valve to determine that it is functioning properly. (c) Each operator shall...

  9. 49 CFR 195.420 - Valve maintenance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Valve maintenance. 195.420 Section 195.420... PIPELINE Operation and Maintenance § 195.420 Valve maintenance. (a) Each operator shall maintain each valve..., inspect each mainline valve to determine that it is functioning properly. (c) Each operator shall...

  10. 49 CFR 195.116 - Valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Valves. 195.116 Section 195.116 Transportation... PIPELINE Design Requirements § 195.116 Valves. Each valve installed in a pipeline system must comply with the following: (a) The valve must be of a sound engineering design. (b) Materials subject to...

  11. Safety valve apparatus and method

    SciTech Connect

    Hynes, J. H.; Morrill, Ch.

    1984-10-16

    A safety valve for controlling flow in a flow line is disclosed which is especially adapted for use in emergency control of a producing well. The apparatus includes means for securing a punch out tube in series with the flow line and ramming means for ramming the punch out tube and displacing at least a portion of it from the flow path of the flow line and sealing the flow line. The punch out tube comprises top, bottom and middle cylindrical members stacked end to end with an elastomeric seal provided in channels resulting from cooperating grooves formed in the end surfaces of the members. When the middle member is rammed, while the bottom and top members are fixed within the valve body, the middle member is displaced to a valve recess and the ram covers and seals the outlet flow path of the valve. The valve is adapted to be attached between production casing of a production wellhead and a production tree. The production tubing is supported within the valve body. Production flow path is achieved by coupling of the punch out tube to the production tubing and the flow path of an annular packoff. The production tree or a tubular extension to the tree is attached to the top of the valve body. A method and means for accomplishing the method are provided for replacing the punch out tube without removing the production tree from the valve body. A method for installing the valve between a production wellhead and a production tree is also provided.

  12. A reversible molecular valve

    PubMed Central

    Nguyen, Thoi D.; Tseng, Hsian-Rong; Celestre, Paul C.; Flood, Amar H.; Liu, Yi; Stoddart, J. Fraser; Zink, Jeffrey I.

    2005-01-01

    In everyday life, a macroscopic valve is a device with a movable control element that regulates the flow of gases or liquids by blocking and opening passageways. Construction of such a device on the nanoscale level requires (i) suitably proportioned movable control elements, (ii) a method for operating them on demand, and (iii) appropriately sized passageways. These three conditions can be fulfilled by attaching organic, mechanically interlocked, linear motor molecules that can be operated under chemical, electrical, or optical stimuli to stable inorganic porous frameworks (i.e., by self-assembling organic machinery on top of an inorganic chassis). In this article, we demonstrate a reversibly operating nanovalve that can be turned on and off by redox chemistry. It traps and releases molecules from a maze of nanoscopic passageways in silica by controlling the operation of redox-activated bistable [2]rotaxane molecules tethered to the openings of nanopores leading out of a nanoscale reservoir. PMID:16006520

  13. 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).

  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. 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.

  16. 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.

  17. Management of the Nasal Valve.

    PubMed

    Barrett, Dane M; Casanueva, Fernando J; Cook, Ted A

    2016-08-01

    The nasal valve is an important consideration in patients presenting with nasal obstruction. Controversy exists regarding the anatomy, terminology, evaluation, and management of the nasal valve. Innumerable techniques with variable effects have been described in the literature. The evidence qualifying these techniques has been plentiful, though often lacking in quality. This article reviews the controversial aspects of nasal valve management applying the best available evidence to help clarify potential areas of confusion. Future research using standardized definitions, consistent methodologies, and validated outcome measures are necessary to improve the quality of evidence and impact surgical decision-making. PMID:27400837

  18. 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.

  19. Dual-Flow-Rate Valve

    NASA Technical Reports Server (NTRS)

    Allbritain, R. H.

    1986-01-01

    Flow-control device precisely adjusted for two rates. Heart of twoposition valve is sliding poppet. At far-right position, poppet allows low flow. At far-left position, allows high flow. Valve supplies high-pressure gas at either of two preselected flow rates. Valve adjustable between 0.12 and 1.2 lb/s (0.054 and 0.54 kg/s) of hydrogen at 3,300 lb/in.2 (23 MN/m2) and 80 degrees F (27 degrees C). Two flow rates preadjusted between these limits in increments of 0.01 lb/s (0.0045 kg/s).

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

    PubMed Central

    Ramakrishna, Harish; DeValeria, Patrick A.; Sweeney, John P.; Mookaram, Farouk

    2015-01-01

    Transcatheter valve implantation continues to grow worldwide and has been used principally for the nonsurgical management of native aortic valvular disease-as a potentially less invasive method of valve replacement in high-risk and inoperable patients with severe aortic valve stenosis. Given the burden of valvular heart disease in the general population and the increasing numbers of patients who have had previous valve operations, we are now seeing a growing number of high-risk patients presenting with prosthetic valve stenosis, who are not potential surgical candidates. For this high-risk subset transcatheter valve delivery may be the only option. Here, we present an inoperable patient with severe, prosthetic valve aortic and mitral stenosis who was successfully treated with a trans catheter based approach, with a valve-in-valve implantation procedure of both aortic and mitral valves. PMID:25849702

  1. 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)

  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. Nontuberculous Mycobacteria: An Underestimated Cause of Bioprosthetic Valve Infective Endocarditis.

    PubMed

    Bouchiat, Coralie; Saison, Julien; Boisset, Sandrine; Flandrois, Jean-Pierre; Issartel, Bertrand; Dauwalder, Olivier; Benito, Yvonne; Jarraud, Sophie; Grando, Jacqueline; Boibieux, Andre; Dumitrescu, Oana; Delahaye, François; Farhat, Fadi; Thivolet-Bejui, Françoise; Frieh, Jean-Philippe; Vandenesch, François

    2015-04-01

    Background.  Atypical mycobacteria, or nontuberculous mycobacteria (NTM), have been barely reported as infective endocarditis (IE) agents. Methods.  From January 2010 to December 2013, cardiac valve samples sent to our laboratory as cases of blood culture-negative suspected IE were analyzed by 16S rDNA polymerase chain reaction (PCR). When positive for NTM, hsp PCR allowed species identification. Demographic, clinical, echocardiographic, histopathological, and Ziehl-Neelsen staining data were then collected. Results.  Over the study period, 6 of 370 cardiac valves (belonging to 5 patients in 3 hospitals) were positive for Mycobacterium chelonae (n = 5) and Mycobacterium lentiflavum (n = 1) exclusively on bioprosthetic material. The 5 patients presented to the hospital for heart failure without fever 7.1-18.9 months (median 13.1 months) after biological prosthetic valve implantation. Echocardiography revealed paravalvular regurgitation due to prosthesis dehiscence in all patients. Histopathological examination of the explanted material revealed inflammatory infiltrates in all specimens, 3 of which were associated with giant cells. Gram staining and conventional cultures remained negative, whereas Ziehl-Neelsen staining showed acid-fast bacilli in all patients. Allergic etiology was ruled out by antiporcine immunoglobulin E dosages. These 5 cases occurred exclusively on porcine bioprosthetic material, revealing a statistically significant association between bioprosthetic valves and NTM IE (P < .001). Conclusions.  The body of evidence confirmed the diagnosis of prosthetic IE. The statistically significant association between bioprosthetic valves and NTM IE encourages systematic Ziehl-Neelsen staining of explanted bioprosthetic valves in case of early bioprosthesis dysfunction, even without an obvious sign of IE. In addition, we strongly question the cardiac bioprosthesis conditioning process after animal sacrifice. PMID:26213691

  4. Nontuberculous Mycobacteria: An Underestimated Cause of Bioprosthetic Valve Infective Endocarditis

    PubMed Central

    Bouchiat, Coralie; Saison, Julien; Boisset, Sandrine; Flandrois, Jean-Pierre; Issartel, Bertrand; Dauwalder, Olivier; Benito, Yvonne; Jarraud, Sophie; Grando, Jacqueline; Boibieux, Andre; Dumitrescu, Oana; Delahaye, François; Farhat, Fadi; Thivolet-Bejui, Françoise; Frieh, Jean-Philippe; Vandenesch, François

    2015-01-01

    Background. Atypical mycobacteria, or nontuberculous mycobacteria (NTM), have been barely reported as infective endocarditis (IE) agents. Methods. From January 2010 to December 2013, cardiac valve samples sent to our laboratory as cases of blood culture-negative suspected IE were analyzed by 16S rDNA polymerase chain reaction (PCR). When positive for NTM, hsp PCR allowed species identification. Demographic, clinical, echocardiographic, histopathological, and Ziehl-Neelsen staining data were then collected. Results. Over the study period, 6 of 370 cardiac valves (belonging to 5 patients in 3 hospitals) were positive for Mycobacterium chelonae (n = 5) and Mycobacterium lentiflavum (n = 1) exclusively on bioprosthetic material. The 5 patients presented to the hospital for heart failure without fever 7.1–18.9 months (median 13.1 months) after biological prosthetic valve implantation. Echocardiography revealed paravalvular regurgitation due to prosthesis dehiscence in all patients. Histopathological examination of the explanted material revealed inflammatory infiltrates in all specimens, 3 of which were associated with giant cells. Gram staining and conventional cultures remained negative, whereas Ziehl-Neelsen staining showed acid-fast bacilli in all patients. Allergic etiology was ruled out by antiporcine immunoglobulin E dosages. These 5 cases occurred exclusively on porcine bioprosthetic material, revealing a statistically significant association between bioprosthetic valves and NTM IE (P < .001). Conclusions. The body of evidence confirmed the diagnosis of prosthetic IE. The statistically significant association between bioprosthetic valves and NTM IE encourages systematic Ziehl-Neelsen staining of explanted bioprosthetic valves in case of early bioprosthesis dysfunction, even without an obvious sign of IE. In addition, we strongly question the cardiac bioprosthesis conditioning process after animal sacrifice. PMID:26213691

  5. 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.

  6. Living with Heart Valve Disease

    MedlinePlus

    ... Clinical Trials Links Related Topics Congenital Heart Defects Endocarditis Heart Murmur How the Heart Works Mitral Valve ... your doctor if you have symptoms of infective endocarditis (IE). Symptoms of this heart infection include fever, ...

  7. Risks for Heart Valve Problems

    MedlinePlus

    ... had rheumatic fever or a case of infective endocarditis are at greater risk for heart valve problems. ... needed before dental procedures to help protect against endocarditis . You should discuss your individual risk and the ...

  8. What Causes Heart Valve Disease?

    MedlinePlus

    ... Clinical Trials Links Related Topics Congenital Heart Defects Endocarditis Heart Murmur How the Heart Works Mitral Valve ... This rare but serious infection is called infective endocarditis . The germs can enter the bloodstream through needles, ...

  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. Options for Heart Valve Replacement

    MedlinePlus

    ... and links along the way. Additional resources from Adam Pick's blog: Surgeon Q&A: Taking Asymmetric Information Out of the Surgical Process with Dr. John Byrne Un dergoing Heart Valve Surgery: 6 Steps ...

  11. Facts and fiction surrounding the discovery of the venous valves.

    PubMed

    Scultetus, A H; Villavicencio, J L; Rich, N M

    2001-02-01

    circulation. Therefore, our investigations revealed that Estienne and Canano discovered the venous valves in the 1530s. Fabricius ab Aquapendente's achievement was their full recognition 64 years later. However, it was not until 1628 that their function was fully understood, with the discovery of the blood circulation by William Harvey. PMID:11174802

  12. Kelly mud saver valve sub

    SciTech Connect

    Reddoch, J.A.

    1986-12-02

    A mud saver valve is described for preventing drilling mud from escaping from a kelly when a drill string is broken below the kelly, the valve comprising: a tubular valve body having first and second ends, the first end being provided with means for attachment in fluid communicating relationship with the kelly, the second end being provided with means for attachment to the drill string; an annular seat fixed in the interior of the valve body adjacent its first end; a tubular closure member within the valve body. The closure member is provided with a selectively closed seating end for seating in valve closing engagement with the annular seat, an open non-seating end in fluid communicating relationship with the drill string, and an annular expansion in the outer diameter of the closure member adjacent the seating end; a top and bottom spacer ring disposed in sliding relationship around the tubular closure member intermediate the annular expansion and the non-seating end of the closure member. The spacer ring and annular expansion cooperatively define an annular chamber around the closure member; and a helical spring disposed around the closure member towards the annular seat.

  13. Application of Tracking and Data Relay Satellite (TDRS) Differenced One-Way Doppler (DOWD) Tracking Data for Orbit Determination and Station Acquisition Support of User Spacecraft Without TDRS Compatible Transponders

    NASA Technical Reports Server (NTRS)

    Olszewski, A. D., Jr.; Wilcox, T. P.; Beckman, Mark

    1996-01-01

    Many spacecraft are launched today with only an omni-directional (omni) antenna and do not have an onboard Tracking and Data Relay Satellite (TDRS) transponder that is capable of coherently returning a carrier signal through TDRS. Therefore, other means of tracking need to be explored and used to adequately acquire the spacecraft. Differenced One-Way Doppler (DOWD) tracking data are very useful in eliminating the problems associated with the instability of the onboard oscillators when using strictly one-way Doppler data. This paper investigates the TDRS DOWD tracking data received by the Goddard Space Flight Center (GSFC) Flight Dynamics Facility (FDF) during the launch and early orbit phases for the the Interplanetary Physics Laboratory (WIND) and the National Oceanographic and Atmospheric Administration (NOAA)-J missions. In particular FDF personnel performed an investigation of the data residuals and made an assessment of the acquisition capabilities of DOWD-based solutions. Comparisons of DOWD solutions with existing data types were performed and analyzed in this study. The evaluation also includes atmospheric editing of the DOWD data and a study of the feasibility of solving for Doppler biases in an attempt to minimize error. Furthermore, by comparing the results from WIND and NOAA-J, an attempt is made to show the limitations involved in using DOWD data for the two different mission profiles. The techniques discussed in this paper benefit the launches of spacecraft that do not have TDRS transponders on board, particularly those launched into a low Earth orbit. The use of DOWD data is a valuable asset to missions which do not have a stable local oscillator to enable high-quality solutions from the one-way/return-link Doppler tracking data.

  14. Dissection of the atrial wall after mitral valve replacement.

    PubMed Central

    Lukács, L; Kassai, I; Lengyel, M

    1996-01-01

    We describe an unusual sequela of mitral valve replacement in a 50-year-old woman who had undergone a closed mitral commissurotomy in 1975. She was admitted to our hospital because of mitral restenosis in November 1993, at which time her mitral valve was replaced with a mechanical prosthesis. On the 8th postoperative day, the patient developed symptoms of heart failure; transesophageal echocardiography revealed dissection and rupture of the left atrial wall. At prompt reoperation, we found an interlayer dissection and rupture of the atrial wall into the left atrium. We repaired the ruptured atrial wall with a prosthetic patch. The postoperative course was uneventful, and postoperative transesophageal echocardiography showed normal prosthetic valve function and no dissection. Images PMID:8680278

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Comparative hemodynamics in an aorta with bicuspid and trileaflet valves

    NASA Astrophysics Data System (ADS)

    Gilmanov, Anvar; Sotiropoulos, Fotis

    2016-04-01

    Bicuspid aortic valve (BAV) is a congenital heart defect that has been associated with serious aortopathies, such as aortic stenosis, aortic regurgitation, infective endocarditis, aortic dissection, calcific aortic valve and dilatation of ascending aorta. There are two main hypotheses to explain the increase prevalence of aortopathies in patients with BAV: the genetic and the hemodynamic. In this study, we seek to investigate the possible role of hemodynamic factors as causes of BAV-associated aortopathy. We employ the curvilinear immersed boundary method coupled with an efficient thin-shell finite-element formulation for tissues to carry out fluid-structure interaction simulations of a healthy trileaflet aortic valve (TAV) and a BAV placed in the same anatomic aorta. The computed results reveal major differences between the TAV and BAV flow patterns. These include: the dynamics of the aortic valve vortex ring formation and break up; the large-scale flow patterns in the ascending aorta; the shear stress magnitude, directions, and dynamics on the heart valve surfaces. The computed results are in qualitative agreement with in vivo magnetic resonance imaging data and suggest that the linkages between BAV aortopathy and hemodynamics deserve further investigation.